A pig feed for improving slaughter performance and a method for preparing and feeding the same

Abstract

This invention relates to the field of animal nutrition and feed, and discloses a pig feed for improving slaughter performance, as well as its preparation and feeding method. The preparation method includes: using safflower seeds as raw material, adding rosemary ethanol extract, and then subjecting it to solid-state fermentation with Bacillus subtilis to prepare fermented safflower seed powder with a high proportion of C-9,T-11 conjugated linoleic acid; adding the fermented safflower seed powder, oat β-glucan, and selenomethionine-type selenium-enriched yeast to the basal diet of fattening pigs to formulate a compound feed; and feeding the feed continuously from the time the fattening pigs reach a weight of 60 kg until slaughter. This invention selectively inhibits the secondary catalytic conversion of C-9,T-11 conjugated linoleic acid through rosmarinic acid, preserving the proportion of active configurations in the fermentation product; and extends the effective utilization time window of conjugated linoleic acid in the fattening pig through oat β-glucan; thus achieving a comprehensive improvement in slaughter performance, including reduced backfat thickness, increased intramuscular fat content, and improved carcass grade.

Description

Technical Field

[0001] This invention relates to the field of animal nutrition and feed technology, and more specifically, to a pig feed that improves slaughter performance, and a method for its preparation and feeding. Background Technology

[0002] Conjugated linoleic acid (CLA) is a core functional feed ingredient for regulating fat distribution in pig carcasses and improving slaughter grades. C-9,T-11 CLA is the primary active form that inhibits subcutaneous fat deposition and promotes intramuscular fat synthesis. Currently, pig production commonly uses chemically synthesized CLA additives, which suffers from high costs and declining consumer acceptance of artificial additives, leading to a continuously increasing market demand for naturally sourced CLA products. Plant seeds rich in linoleic acid, such as safflower seeds, are natural alternative sources of C-9,T-11 CLA. Linoleic acid (C-9,C-12-octadecadienoic acid) is a direct biosynthetic precursor of C-9,T-11 CLA. Microbial fermentation can convert linoleic acid in plant seeds into C-9,T-11 CLA, simultaneously improving CLA's intestinal bioavailability. However, linoleic acid in plant seeds is encapsulated in plant cell oil bodies and blocked by the cell wall, requiring microbial fermentation to break down the cell walls for full release.

[0003] The aforementioned microbial fermentation technology faces the following unresolved technical problems in the conversion of plant-derived linoleic acid into c-9, t-11 CLA, which restrict the actual effectiveness of natural plant-derived CLA in replacing chemically synthesized CLA: The fatty acid isomerases carried by the fermentation strains not only catalyze the forward conversion of linoleic acid to c-9, t-11 CLA, but also further convert c-9, t-11 CLA into low-activity t-10, c-12 CLA when it accumulates to a high concentration, resulting in a fundamental technical contradiction between fermentation conditions and the integrity of CLA conformation; simultaneously, the absorption rate of free CLA in the small intestine is too rapid, and the effective concentration in vivo is not maintained for a sufficient time; the conjugated double bond structure of CLA makes it susceptible to lipid peroxidation damage in tissues, causing CLA to undergo oxidative degradation before reaching the target tissue, affecting the regulatory effects of subcutaneous fat inhibition and intramuscular fat accumulation. Existing technologies lack targeted solutions to these problems. Summary of the Invention

[0004] The invention provides a pig feed that improves slaughter performance, as well as its preparation and feeding method, which solves the technical problems in related technologies, such as insufficient bioavailability of linoleic acid from plant seeds, secondary degradation of the active configuration of CLA from natural plant-derived fermentation, insufficient time window for effective utilization of CLA in vivo, and loss of CLA activity in vivo.

[0005] This invention provides a method for preparing compound feed to improve the slaughter performance of fattening pigs, comprising the following steps: Step 1: Preparation of Protective Fermented Safflower Seed Powder (the term "protective" refers to the function of protecting the active configuration of C-9,T-11 conjugated linoleic acid by utilizing rosmarinic acid in rosemary extract, preventing it from being further catalyzed by fatty acid isomerases and converted into T-10,C-12 conjugated linoleic acid): Safflower seeds with a linoleic acid content of not less than 70% (accounting for a certain percentage of total fatty acids) are crushed to a particle size of 2-4 mm. 1.5-3.0 g of rosemary extract containing rosmarinic acid is added to every 100 g of crushed safflower seeds. After mixing evenly, the mixture is inoculated with Bacillus subtilis, which has linoleic acid isomerase activity and can secrete cellulase. The substrate moisture content is adjusted to 50%-60%, and aerobic solid-state fermentation is carried out at 35-40℃ for 48-72 h, turning the mixture every 12 h. The fermentation product is dried at a temperature not exceeding 60℃ until the moisture content is not higher than 12% and then pulverized to obtain the protected fermented safflower seed powder. Step 2, Formulate compound feed: Add fermented safflower seed powder, oat β-glucan with a molecular weight of not less than 500 kDa, and organic selenium to the basal diet of fattening pigs, mix evenly, wherein the content of c-9,t-11 type conjugated linoleic acid in the dry matter of the compound feed is 0.8% to 1.2%, the amount of oat β-glucan added is 0.5% to 1.0% of the dry matter of the compound feed, and the amount of organic selenium added is 0.3 to 0.5 mg Se / kg of dry matter of the compound feed; Step 3, feeding: From the time the fattening pigs reach a weight of 60 kg until slaughter, feed them the compound feed obtained in Step 2 continuously at a weight of 2.5% to 3.0% of their body weight, and provide them with free access to water.

[0006] Preferably, the linoleic acid content of the safflower seeds is confirmed by batch-by-batch testing using gas chromatography.

[0007] Preferably, the rosemary extract in step one is a rosemary ethanol extract, and the extraction solvent is a food-grade ethanol solution with a volume fraction of 50% to 75%; the quality standard of the rosemary extract is: the content of rosmarinic acid is not less than 15% and the content of carrageenan acid is not less than 5%, both on a dry weight basis.

[0008] Preferably, the Bacillus subtilis strain described in step one is pre-screened and confirmed to meet the following conditions: under the conditions of fermentation temperature of 35-40℃, substrate moisture content of 50%-60%, and fermentation time of 48-72 h, the conversion rate of c-9,t-11 type conjugated linoleic acid to linoleic acid is not less than 10% (based on the total amount of linoleic acid in the substrate), and the cellulase filter paper enzyme activity (FPase) is not less than 0.5 U / mL of culture medium.

[0009] Preferably, the inoculum size of Bacillus subtilis in step one is 1×10⁻⁶. 7 ~1×10 8 CFU / g substrate.

[0010] Preferably, the purity of the oat β-glucan in step two is not less than 70%.

[0011] Preferably, the organic selenium source in step two is selenomethionine-type selenium-enriched yeast, which is obtained by culturing Saccharomyces cerevisiae in a selenium-enriched culture medium. The quality standard is: the total selenium content is not less than 2000 mg Se / kg of yeast dry product, of which the proportion of organic selenium in the form of selenomethionine is not less than 60% of the total selenium content, and the inorganic selenium residue is not more than 10%.

[0012] Preferably, the actual amount of selenium-enriched yeast added is calculated according to the following formula: Selenium-enriched yeast addition (g / kg dry matter of compound feed) = Target Se addition (mg Se / kg, taken as 0.3~0.5) ÷ Measured total selenium content of selenium-enriched yeast product (mg Se / kg) × 1000; The measured total selenium content of the selenium-enriched yeast product must be determined batch by batch by ICP-MS or atomic fluorescence spectrometry.

[0013] Preferably, the actual amount of fermented safflower seed powder added in step two is determined as follows: The actual content (g / 100 g dry weight) of c-9,t-11 type conjugated linoleic acid in fermented safflower seed powder is determined by high performance liquid chromatography (HPLC). The actual amount is calculated using the formula: Fermented safflower seed powder dosage (g / 100 g dry matter of compound feed) = Target c-9,t-11 type conjugated linoleic acid content (g / 100 g, taken as 0.8~1.2) ÷ Actual content (g / 100 g) of c-9,t-11 type conjugated linoleic acid in fermented safflower seed powder × 100.

[0014] This invention also provides a compound feed for improving the slaughter performance of fattening pigs, the compound feed comprising a basal diet for fattening pigs and the following three functional additives: (1) The fermented safflower seed powder is made by crushing safflower seeds with a linoleic acid content of not less than 70% (accounting for a total fatty acid content) to a particle size of 2-4 mm, mixing them evenly with rosemary extract containing rosmarinic acid at a ratio of 1.5-3.0 g of rosemary extract per 100 g of crushed safflower seeds, inoculating them with Bacillus subtilis with linoleic acid isomerase activity and cellulase secretion, and then carrying out aerobic solid-state fermentation at 35-40℃ for 48-72 h. After drying at a temperature not exceeding 60℃ until the moisture content is not higher than 12%, the powder is then pulverized. The amount added is based on the content of C-9,T-11 type conjugated linoleic acid in the dry matter of the compound feed reaching 0.8%-1.2%. (2) Oat β-glucan, with a molecular weight of not less than 500 kDa and a purity of not less than 70%, is added at a rate of 0.5% to 1.0% of the dry matter in the compound feed; (3) Organic selenium, the amount added is 0.3 to 0.5 mg Se / kg dry matter of compound feed.

[0015] A method for feeding compound feed to improve the slaughter performance of fattening pigs involves starting feeding when the pigs reach a weight of 60 kg and continuing until slaughter. The feed should be given daily at 2.5%–3.0% of the pig's body weight, twice a day (morning and evening), with free access to water.

[0016] The beneficial effects of this invention are as follows: This invention selectively inhibits the secondary conversion catalytic activity of fatty acid isomerase on c-9,t-11 CLA by rosmarinic acid compounds in rosemary ethanol extract, preserving the proportion of active configurations in the fermentation product without affecting the forward conversion efficiency of linoleic acid. This fundamentally solves the fundamental contradiction between fermentation conditions and the integrity of CLA configuration in existing fermentation technologies. Oat β-glucan (molecular weight ≥500 kDa) forms a high-viscosity gel network in the small intestine lumen, transforming CLA from a rapid, concentrated absorption mode to a sustained, slow-release absorption mode, extending the duration of effective CLA concentration in the body after each feeding. Organic selenium (selenomethionine) maintains the complete catalytic activity of glutathione peroxidase, terminating the lipid peroxidation chain reaction and protecting the conjugated double bond structure of c-9,t-11 CLA from oxidative damage. The synergistic effect of these three functional components achieves comprehensive improvement in slaughter performance, including reduced backfat thickness, increased intramuscular fat content, and improved carcass grade in fattening pigs. Simultaneously, the use of naturally derived fermentation products to replace chemically synthesized CLA additives reduces raw material costs. Attached Figure Description

[0017] Figure 1 This is a line graph showing the dynamic changes in the content of c-9, t-11 and t-10, c-12 CLA during fermentation in Experiment 1 of the present invention. Figure 2 This is a line graph showing the change in plasma c-9,t-11 CLA concentration over time in two groups of fattening pigs after feeding in Experiment 2 of the present invention. Figure 3 This is a bar chart showing the GSH-Px activity of the longissimus dorsi muscle in each group of fattening pigs in Experiment 3 of this invention. Figure 4 This is a bar chart showing the MDA content of the longissimus dorsi muscle in each group of fattening pigs in Experiment 3 of this invention. Figure 5 This is a bar chart showing the content of c-9 and t-11 type CLA in the longissimus dorsi muscle of each group of fattening pigs in Experiment 3 of the present invention. Figure 6 This is a bar chart comparing the backfat thickness of three groups of fattening pigs in Experiment 4 of the present invention. Figure 7 This is a bar chart comparing the intramuscular fat content of three groups of fattening pigs in Experiment 4 of the present invention. Figure 8 This is a bar chart comparing the ocular muscle area of ​​three groups of fattening pigs in Experiment 4 of the present invention. Figure 9 This is a bar chart comparing the feed conversion rates of the three groups of fattening pigs in Experiment 4 of the present invention. Figure 10 These are tissue sections (200x magnification) of the longissimus dorsi muscle stained with Oil Red O in three groups of fattening pigs in Experiment 4 of the present invention. Detailed Implementation

[0018] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, some features described in the examples may be combined in other examples.

[0019] Example 1

[0020] This embodiment discloses a method for preparing compound feed to improve the slaughter performance of fattening pigs, the method comprising the following steps: Step 1: Prepare fermented safflower seed powder: Safflower seeds were collected, and their linoleic acid content was determined to be 75% (accounting for 75% of total fatty acids) using gas chromatography, confirming that it meets the ≥70% feeding standard. The safflower seeds were then crushed into 3 mm particles using a roller crusher, a rapid process completed in 8 minutes.

[0021] Add 2.0 g of rosemary ethanol extract (using a 60% food-grade ethanol solution as the extraction solvent; the extract was found to contain 18% rosmarinic acid and 6% carrageenan acid, both on a dry weight basis) to every 100 g of crushed safflower seeds. Stir thoroughly for 4 min to ensure that the rosemary ethanol extract is evenly coated on the surface of the crushed safflower seeds, thus obtaining a protective mixed substrate.

[0022] The Bacillus subtilis strain used was pre-screened and confirmed to achieve a 12% conversion rate of c-9,t-11 conjugated linoleic acid (based on total substrate linoleic acid) under fermentation conditions of 37℃, 55% substrate moisture content, and 60 h, with a cellulase filter paper enzyme activity (FPase) of 0.8 U / mL culture medium. An appropriate amount of water was added to the substrate mixture to adjust the moisture content to 55%; the above-mentioned Bacillus subtilis strain was then inoculated at an inoculum size of 5 × 10⁻⁶. 7CFU / g substrate; after mixing evenly, spread the substrate in the fermentation container to a thickness of 12 cm, cover with a sterile filter membrane with a pore size of 0.22 μm, and incubate at 37℃ for aerobic solid-state fermentation for 60 h, turning the substrate once every 12 h (for a total of 4 times).

[0023] After fermentation, the fermentation product was dried at 55℃ with forced air until the moisture content was 10%, pulverized to a particle size ≤1 mm, and stored in a sealed, light-protected container to obtain fermented safflower seed powder. High-performance liquid chromatography (HPLC) analysis showed that the C-9,T-11 type conjugated linoleic acid content in this fermented safflower seed powder was 7.0 g / 100 g dry weight.

[0024] Step 2, prepare compound feed: A basic diet for fattening pigs was formulated based on corn-soybean meal.

[0025] Three functional additives were added to the basic diet: (1) Fermented safflower seed powder: Based on the HPLC measured CLA content of 7.0 g / 100 g, and with a target CLA content of 1.0%, the amount of fermented safflower seed powder used is 1.0 ÷ 7.0 × 100 = 14.3 g / 100 g of dry matter in compound feed, that is, 14.3 g of fermented safflower seed powder is added to every 100 g of dry matter in compound feed; (2) Oat β-glucan (molecular weight 600 kDa, purity 75%), the addition amount is 0.75% of the dry matter of the compound feed; (3) Selenium-enriched yeast of selenomethionine type (using Saccharomyces cerevisiae as the source, the total selenium content of yeast dry product was 2500 mg Se / kg as detected by ICP-MS, with organic selenium in the form of selenomethionine accounting for 65% of the total selenium content and inorganic selenium residue of 8%): Based on the target Se addition amount of 0.4 mg Se / kg, the amount of selenium-enriched yeast added = 0.4 ÷ 2500 ×1000 = 0.16 g / kg dry matter of compound feed.

[0026] The three functional additives mentioned above were added to the basal diet and thoroughly mixed to obtain a compound feed. The dry matter content of this compound feed was 1.0% c-9,t-11 type CLA, 0.75% oat β-glucan, and 0.4 mgSe / kg.

[0027] Step 3, feeding the fattening pigs: When the fattening pigs reach a weight of 60 kg, start feeding them the compound feed obtained in step two. Feed them 2.75% of their body weight daily, twice a day, in the morning and evening, and provide them with free access to water. Continue feeding them until they are ready for market.

[0028] Example 2

[0029] This embodiment discloses a method for preparing compound feed to improve the slaughter performance of fattening pigs, the method comprising the following steps: Step 1: Prepare fermented safflower seed powder: Safflower seeds were collected, and their linoleic acid content was determined to be 72% (accounting for 72% of total fatty acids) using gas chromatography, confirming that it meets the ≥70% feeding standard. The safflower seeds were then crushed to a particle size of 2 mm using a roller crusher for 8 minutes.

[0030] Add 1.5 g of rosemary ethanol extract (using 50% food-grade ethanol solution as the extraction solvent; the extract was found to contain 15% rosmarinic acid and 5% carrageenan acid, both on a dry weight basis) to every 100 g of crushed safflower seeds, and mix thoroughly for 4 min to obtain the protective mixed substrate.

[0031] The Bacillus subtilis strain used was pre-screened and confirmed to achieve a 10% conversion rate of c-9,t-11 conjugated linoleic acid (based on total substrate linoleic acid) under fermentation conditions of 35℃, 50% substrate moisture content, and 48 h, with a cellulase filter paper enzyme activity (FPase) of 0.5 U / mL culture medium. An appropriate amount of water was added to the substrate mixture to adjust the moisture content to 50%; the above-mentioned Bacillus subtilis strain was inoculated at an inoculum size of 1×10⁻⁶. 7 CFU / g substrate; after mixing evenly, spread it in the fermentation container to a thickness of 12 cm, cover with a sterile filter membrane with a pore size of 0.22 μm, and carry out aerobic solid-state fermentation at 35℃ for 48 h, turning the material once every 12 h (for a total of 3 times).

[0032] After fermentation, the fermentation product was dried at 50℃ with forced air until the moisture content was 10%, pulverized to a particle size ≤1 mm, and stored in a sealed, light-protected container to obtain fermented safflower seed powder. HPLC analysis showed that the C-9,T-11 type conjugated linoleic acid content in this fermented safflower seed powder was 5.5 g / 100 g dry weight.

[0033] Step 2, prepare compound feed: A basic diet for fattening pigs was formulated based on corn-soybean meal.

[0034] (1) Hugo fermented safflower seed powder: Based on the HPLC measured CLA content of 5.5 g / 100 g, and with a target CLA content of 0.8%, the amount of Hugo fermented safflower seed powder used is 0.8 ÷ 5.5 × 100 ≈ 14.5 g / 100 g of dry matter in compound feed; (2) Oat β-glucan (molecular weight 500 kDa, purity 70%), the addition amount is 0.5% of the dry matter of the compound feed; (3) Selenium-enriched yeast of selenomethionine type (from brewer's yeast, with a total selenium content of 2000 mg Se / kg of yeast dry product as determined by atomic fluorescence spectrometry, with organic selenium in the form of selenomethionine accounting for 60% of the total selenium content and inorganic selenium residue of 10%): Based on the target Se addition amount of 0.3 mg Se / kg, the amount of selenium-enriched yeast added = 0.3 ÷ 2000 × 1000 = 0.15 g / kg of dry matter in compound feed.

[0035] The three functional additives mentioned above were added to the basal diet and thoroughly mixed to obtain a compound feed. The dry matter content of this compound feed was 0.8% c-9,t-11 type CLA, 0.5% oat β-glucan, and 0.3 mgSe / kg.

[0036] Step 3, feeding the fattening pigs: When the fattening pigs reach a weight of 60 kg, start feeding them compound feed at a rate of 2.5% of their body weight per day, twice a day, morning and evening, with free access to water, and continue feeding until slaughter.

[0037] Example 3

[0038] This embodiment discloses a method for preparing compound feed to improve the slaughter performance of fattening pigs, the method comprising the following steps: Step 1: Prepare fermented safflower seed powder: Safflower seeds were collected, and their linoleic acid content was determined to be 78% (accounting for 78% of total fatty acids) using gas chromatography, confirming that it meets the ≥70% feeding standard. The safflower seeds were then crushed to a particle size of 4 mm using a roller crusher for 9 minutes.

[0039] Add 3.0 g of rosemary ethanol extract (using a 75% food-grade ethanol solution as the extraction solvent; the extract was found to contain 20% rosmarinic acid and 8% carrageenan acid, both on a dry weight basis) to every 100 g of crushed safflower seeds, and mix thoroughly for 5 min to obtain the protective mixed substrate.

[0040] The Bacillus subtilis strain used was pre-screened and confirmed to achieve a 15% conversion rate of c-9,t-11 conjugated linoleic acid (based on total substrate linoleic acid) under fermentation conditions of 40℃, 60% substrate moisture content, and 72 h, with a cellulase filter paper enzyme activity (FPase) of 1.2 U / mL culture medium. An appropriate amount of water was added to the substrate mixture to adjust the moisture content to 60%; the above-mentioned Bacillus subtilis strain was then inoculated at an inoculum size of 1×10⁻⁶. 8CFU / g substrate; after mixing evenly, spread it in the fermentation container to a thickness of 12 cm, cover with a sterile filter membrane with a pore size of 0.22 μm, and carry out aerobic solid-state fermentation at 40℃ for 72 h, turning the material once every 12 h (for a total of 5 times).

[0041] After fermentation, the fermentation product was dried at 60℃ with forced air until the moisture content was 12%, pulverized to a particle size ≤1 mm, and stored in a sealed, light-protected container to obtain fermented safflower seed powder. HPLC analysis showed that the C-9,T-11 type conjugated linoleic acid content in this fermented safflower seed powder was 9.5 g / 100 g dry weight.

[0042] Step 2, prepare compound feed: A basic diet for fattening pigs was formulated based on corn-soybean meal.

[0043] (1) Hugo fermented safflower seed powder: Based on the HPLC measured CLA content of 9.5 g / 100 g, and with a target CLA content of 1.2%, the amount of Hugo fermented safflower seed powder used is 1.2 ÷ 9.5 × 100 ≈ 12.6 g / 100 g of dry matter in compound feed; (2) Oat β-glucan (molecular weight 800 kDa, purity 80%), the amount added is 1.0% of the dry matter of the compound feed; (3) Selenium-enriched yeast of selenomethionine type (source: brewer's yeast, with a total selenium content of 3000 mgSe / kg yeast dry product as determined by ICP-MS, with organic selenium in the form of selenomethionine accounting for 70% of the total selenium content and inorganic selenium residue of 6%): Based on the target Se addition amount of 0.5 mg Se / kg, the amount of selenium-enriched yeast added = 0.5 ÷ 3000 × 1000 ≈ 0.167 g / kg dry matter of compound feed.

[0044] The three functional additives mentioned above were added to the basal diet and thoroughly mixed to obtain a compound feed. The dry matter content of this compound feed was 1.2% of c-9,t-11 type CLA, 1.0% of oat β-glucan, and 0.5 mgSe / kg.

[0045] Step 3, feeding the fattening pigs: When the fattening pigs reach a weight of 60 kg, start feeding them compound feed at 3.0% of their body weight daily, twice a day, morning and evening, with free access to water, and continue feeding until slaughter.

[0046] Example 4

[0047] This embodiment discloses a compound feed for improving the slaughter performance of fattening pigs. The compound feed includes a basal diet for fattening pigs and the following three functional additives: Functional Additive 1: Protective Fermented Safflower Seed Powder The fermented safflower seed powder was prepared as follows: Safflower seeds with a linoleic acid content of 73% (confirmed by gas chromatography) were crushed to a particle size of 3 mm using a roller crusher for 8 minutes; 2.5 g of rosemary ethanol extract (using 65% food-grade ethanol solution as the extraction solvent; rosmarinic acid content 16%, carrageenan acid content 5%, both on a dry weight basis) were added to every 100 g of crushed safflower seed particles and stirred for 4 minutes; Bacillus subtilis strain (pre-screened and confirmed: c-9, t-11 CLA conversion rate 10%, FPase 0.6 U / mL culture medium) was inoculated at a density of 3 × 10⁻⁶. 7 CFU / g substrate; adjust substrate moisture content to 52%; spread in fermentation container (layer thickness 12 cm), cover with 0.22 μm sterile filter membrane, and carry out aerobic solid-state fermentation at 38℃ for 56 h, turning the substrate every 12 h (for a total of 4 times); after fermentation, dry at 55℃ with forced air to a moisture content of 11%, pulverize to a particle size ≤1 mm, and store in a sealed, light-proof container.

[0048] HPLC analysis revealed that the C-9,T-11 conjugated linoleic acid (CLA) content in the fermented safflower seed powder was 6.5 g / 100g dry weight. Based on the target CLA content of 0.9%, the optimal addition amount of fermented safflower seed powder to the dry matter of the compound feed is: 0.9 ÷ 6.5 × 100 ≈ 13.8 g / 100g dry matter of the compound feed.

[0049] Functional Additive 2: Oat β-glucan The oat-derived β-glucan has a molecular weight of 600 kDa and a purity of 72%. The addition amount is 0.8% of the dry matter in the compound feed.

[0050] Functional Additive 3: Selenium-enriched yeast with selenomethionine A selenomethionine-enriched yeast, cultured using *Saccharomyces cerevisiae* as the inoculum in a selenium-enriched medium, had a total selenium content of 2200 mg Se / kg of dry yeast product as determined by ICP-MS. Organic selenium in the form of selenomethionine accounted for 62% of the total selenium, while inorganic selenium residue remained at 9%. Based on a target Se addition of 0.35 mg Se / kg, the required amount of selenium-enriched yeast is: 0.35 ÷ 2200 × 1000 ≈ 0.159 g / kg of dry matter in the formulated feed.

[0051] Composition of compound feed: The three functional additives mentioned above were thoroughly mixed with a corn-soybean meal-based basal diet for fattening pigs to obtain a compound feed. The dry matter content of this compound feed was 0.9% c-9,t-11 type CLA, 0.8% oat β-glucan, and 0.35 mg Se / kg.

[0052] This compound feed is used for fattening pigs from 60 kg to slaughter weight. It is fed at 2.75% of the fattening pig's body weight daily, twice a day, morning and evening, with free access to water, and is continuously fed until slaughter.

[0053] Example 5

[0054] This embodiment discloses a method for preparing pig feed that improves slaughter performance, the method comprising the following steps: Step 1: Preparation of Rosemary-Protective Fermented Safflower Seed Powder (The term "protective" refers to the targeted protection of the target product's configuration by adding natural antioxidants / enzyme inhibitors to the microbial fermentation system. In this invention, it specifically refers to the function of using rosmarinic acid from rosemary extract to protect the active configuration of C-9,T-11 conjugated linoleic acid, preventing it from being further catalyzed by fatty acid isomerases and converted into T-10,C-12 conjugated linoleic acid.) (1) Raw material selection and pretreatment: Safflower seeds (linoleic acid content ≥70%, accounting for a certain percentage of total fatty acids, confirmed by gas chromatography) are selected as fermentation raw materials. The linoleic acid content of each batch of safflower seeds must be tested by gas chromatography to confirm that it is not less than 70% (accounting for a certain percentage of total fatty acids) before they can be used as raw materials.

[0055] Before feeding, qualified safflower seeds undergo a crushing pretreatment: a roller crusher is used to crush the safflower seeds into particles with a diameter of approximately 3 mm, with a single batch crushing time not exceeding 10 minutes. The purpose of the crushing pretreatment is to break down the seed coat barrier, increase the specific surface area of ​​the substrate, and allow the extracellular cellulase and hemicellulase secreted by Bacillus subtilis to fully contact the cell wall structure inside the seed, thereby improving the cell wall degradation efficiency and linoleic acid release efficiency; at the same time, it increases the contact area between linoleic acid and linoleic acid isomerase (LAI), improving the CLA conversion rate.

[0056] (2) Preparation of rosemary protective substrate: Add 2.0 g of rosemary ethanol extract (using 60% ethanol solution as extraction solvent, food grade; quality standard: rosmarinic acid content ≥15% and sarsaparilla acid content ≥5%, both based on dry weight) to every 100 g of safflower seed crushed particles obtained in step (1), stir thoroughly and mix evenly so that the rosemary ethanol extract is evenly coated on the surface of the safflower seed crushed particles to obtain a protective mixed substrate containing rosemary extract.

[0057] Rosmarinic acid compounds in rosemary ethanol extract selectively inhibit the secondary conversion of c-9,t-11 CLA to t-10,c-12 CLA catalyzed by fatty acid isomerases, while having minimal interference with the first step of the forward conversion of linoleic acid to c-9,t-11 CLA and with cellulase / hemicellulase. Rhusric acid (≥5%, dry weight) in rosemary ethanol extract simultaneously provides antioxidant protection for CLA already generated in the fermentation products during the heat-generating stage, preventing CLA oxidative inactivation during the heat accumulation stage of fermentation.

[0058] (3) Solid-state fermentation: Add an appropriate amount of water to the substrate mixture to adjust the substrate moisture content to 55%; inoculate with a Bacillus subtilis strain that has the ability to produce c-9,t-11 type conjugated linoleic acid through linoleic acid isomerization and can secrete cellulase (FPase ≥ 0.5 U / mL culture medium) and hemicellulase, with an inoculation amount of 5 × 10⁻⁶. 7 CFU / g substrate; the strain used must be pre-screened and confirmed to have a C-9, T-11 CLA conversion rate of linoleic acid ≥10% (based on total linoleic acid in the substrate) under fermentation conditions (37℃, substrate moisture content 55%, 60 h).

[0059] After inoculation, the substrate was mixed thoroughly and spread in a fermentation vessel, with a substrate layer thickness not exceeding 15 cm. A sterile filter membrane with a pore size of 0.22 μm was then used to cover the substrate, and aerobic solid-state fermentation was carried out at 37℃ for 60 h. During fermentation, the substrate was turned over every 12 h to replenish oxygen, dissipate fermentation heat, and ensure uniform enzyme activity.

[0060] (4) Drying and pulverizing: After fermentation, the fermentation product is dried at 55°C with forced air until the moisture content is ≤10%; after drying, the fermentation product is pulverized to a particle size of ≤1 mm to obtain rosemary fermented safflower seed powder, which is sealed and stored away from light for later use.

[0061] Step 2: Prepare compound feed A standard basal diet for fattening pigs is formulated based on corn-soybean meal. Three functional additives are then added to the basal diet at the following dosages to prepare the compound feed: (1) Addition of fermented safflower seed powder: The actual content of c-9,t-11 CLA in the fermented safflower seed powder obtained in step one was detected by high performance liquid chromatography (HPLC) (unit: g / 100 g dry weight). Based on the target value—the content of c-9,t-11 CLA in the dry matter of the compound feed is 1.0%—the actual amount of fermented safflower seed powder was calculated and added to the basal diet. The calculation method is as follows: The dosage of fermented seed powder for feed (g / 100 g dry matter) = 1.0 ÷ Actual CLA content in fermented seed powder (g / 100 g) × 100 (2) Addition of oat β-glucan: Add oat-derived β-glucan (molecular weight ≥500 kDa, purity ≥70%) to the basal diet at a rate of 0.75% of the dry matter of the compound feed.

[0062] High molecular weight (≥500 kDa) oat β-glucan swells in the aqueous environment of the small intestine, forming a continuous high-viscosity gel network. This significantly increases the thickness of the unstirred water layer (UWL) on the intestinal epithelial surface, thereby slowing down the diffusion rate of CLA-fat micelles to the intestinal epithelial surface. This transforms CLA from a rapid and concentrated absorption mode to a sustained and slow-release absorption mode, prolonging the maintenance time of the effective concentration of CLA in vivo.

[0063] (3) Addition of selenium-enriched yeast: Selenium-enriched yeast of selenomethionine type (obtained by culturing Saccharomyces cerevisiae in selenium-enriched medium; quality standard: total selenium content ≥2000 mg Se / kg dry yeast product, organic selenium (selenomethionine form) accounting for ≥60% of total selenium, and inorganic selenium residue ≤10%) is added to the basal diet as an organic selenium source, and the addition amount is calculated according to the following formula: Selenium-enriched yeast addition amount (g / kg dry matter in compound feed) = 0.4 ÷ Actual measured total selenium content of selenium-enriched yeast product (mg Se / kg) × 1000 The total selenium content in the dry matter of the compound feed should reach 0.4 mg Se / kg. The total selenium content of selenium-enriched yeast products must be determined batch by batch using ICP-MS or atomic fluorescence spectrometry.

[0064] (4) Thoroughly mix the above functional additives with the basal diet to obtain compound feed. The dosage of each functional additive is summarized below:

[0065] Step 3: Feeding fattening pigs When the fattening pigs reach a weight of 60 kg during the fattening period, start feeding them the compound feed obtained in step two. Feed them 2.75% of their body weight daily, twice a day (once in the morning and once in the evening), and provide them with free access to water until they are ready for market.

[0066] Experimental verification Experiment 1: Verification of the effect of rosemary structure preservation process on the proportion of active CLA configuration in fermentation products 1. Experimental Objective This study aimed to verify whether premixing rosemary ethanol extract with the fermentation substrate during the solid-state fermentation of safflower seeds by Bacillus subtilis could effectively inhibit the secondary catalytic conversion of c-9,t-11 CLA by fatty acid isomerase (LAI) and preserve the active configuration ratio of c-9,t-11 CLA in the product under fully fermented conditions.

[0067] 2. Preparation of experimental samples Based on the process parameters of Example 1, a control group (CK group) and a protective structure group (RA group) were set up, with 3 parallel replicates for each.

[0068] Control group (CK group): Safflower seeds with a linoleic acid content of 75% (detected by gas chromatography) were crushed to a particle size of 3 mm using a roller crusher; no rosemary ethanol extract was added; water was added to each 100 g of crushed particles to adjust the substrate moisture content to 55%; and Bacillus subtilis (5×10⁻⁶) was inoculated. 7 (CFU / g substrate); after mixing evenly, spread it in the fermentation container to a thickness of 12cm, cover with a sterile filter membrane with a pore size of 0.22 μm, and carry out aerobic solid-state fermentation at 37℃, turning the material once every 12 hours.

[0069] The RA group was identical to the CK group except that 2.0 g of rosemary ethanol extract (60% food-grade ethanol solution as the extraction solvent, 18% rosmarinic acid and 6% sarcopenic acid, all on dry weight) was premixed into every 100 g of crushed safflower seeds before inoculation.

[0070] Both groups were sampled at 0 h, 12 h, 24 h, 36 h, 48 h, 60 h, and 72 h for testing.

[0071] 3. Experimental conditions Fermentation temperature: 37℃; substrate moisture content: 55%; layer thickness: 12 cm; aeration method: covering with a sterile filter membrane with a pore size of 0.22 μm; turning over once every 12 h.

[0072] 4. Experimental Procedure (1) Take 5 g of fermentation sample at each time point, weigh accurately, add 20 mL of 75% ethanol solution, shake and extract for 1 h on a shaker, centrifuge at 5000 rpm for 10 min, and take the supernatant for later use.

[0073] (2) The contents of c-9, t-11 and t-10, c-12 CLA in the supernatant were determined by high performance liquid chromatography (HPLC): the chromatographic column was a C18 reversed-phase column (250 mm × 4.6 mm, 5 μm), the mobile phase was acetonitrile / water (volume ratio 85:15), the flow rate was 1.0 mL / min, the detection wavelength was 233 nm (characteristic absorption peak of CLA conjugated double bond), and the column temperature was 30℃; standard curves were plotted using commercial c-9, t-11 CLA and t-10, c-12 CLA standards for quantification.

[0074] (3) Convert the test results to the substrate dry weight standard (g / 100 g substrate dry weight), and calculate the c-9, t-11 type CLA content, t-10, c-12 type CLA content and active configuration ratio (the ratio of c-9, t-11 type to t-10, c-12 type content) of the two groups at each time point.

[0075] 5. Experimental Results Table 1. CLA content and active configuration ratio of c-9, t-11 and t-10, c-12 types at different fermentation time points (g / 100 g substrate dry weight)

[0076] Figure 1 Line graphs showing the dynamic changes in CLA content of c-9, t-11 and t-10, c-12 types during fermentation.

[0077] 6. Analysis and Summary In the control group (CK group), c-9 and t-11 CLA reached a peak of 6.18 g / 100 g at 48 h of fermentation. Subsequently, it continued to decline due to the accelerated secondary catalytic reaction of fatty acid isomerase, and dropped to 5.08 g / 100 g at 72 h. t-10 and c-12 CLA, on the other hand, continued to accumulate to 5.35 g / 100 g, and the active configuration ratio dropped to 0.95, indicating that the content of t-10 and c-12 CLA had exceeded that of c-9 and t-11 CLA, and the regulatory direction of fermentation products on the adipose tissue of fattening pigs tended to reverse.

[0078] In the RA group, the c-9 and t-11 CLA content continuously increased throughout the fermentation process, reaching 7.58 g / 100 g (substrate dry weight) at the 60-h fermentation endpoint specified in Example 1, and further increasing to 8.12 g / 100 g at 72 h. The t-10 and c-12 CLA content was controlled below 1.0 g / 100 g throughout the fermentation process, and the active configuration ratio stabilized above 8.9 after 36 h of fermentation. Compared with the same time point at 60 h, the c-9 and t-11 CLA content in the RA group was 28.0% higher than that in the CK group (5.92 g / 100 g), while the t-10 and c-12 CLA content decreased from 4.13 g / 100 g to 0.83 g / 100 g (a decrease of 79.9%), and the active configuration ratio increased from 1.4 to 9.1, an increase of approximately 6.5 times.

[0079] The results demonstrate that premixing rosemary ethanol extract into the fermentation substrate can effectively preserve the active configuration ratio of c-9,t-11 CLA in the fermentation product, verifying the internal consistency of this technical solution.

[0080] Experiment 2: Effects of oat β-glucan on plasma CLA uptake kinetics in fattening pigs after feed intake 1. Experimental Objective To verify whether adding oat β-glucan with a molecular weight ≥500 kDa to compound feed can slow down the absorption rate of CLA by increasing the thickness of the unstirred water layer (UWL) in the small intestine, thereby changing the absorption mode of CLA from rapid and concentrated absorption to continuous and slow-release absorption, and prolonging the maintenance time of the effective concentration of CLA in the body after feeding.

[0081] 2. Preparation of experimental samples Twelve fattening pigs (Landrace × Large White × Duroc three-way crossbred pigs) weighing approximately 70 kg were selected and randomly divided into two groups of six pigs each. Each group was fed the following formulated feed: Control group (BG0 group): The fermented safflower seed powder was prepared according to Example 1. 14.3 g / 100 g of fermented safflower seed powder was added to the basal diet (HPLC measured c-9,t-11 CLA content was 7.0 g / 100 g, making the c-9,t-11 CLA content in the dry matter of the compound feed 1.0%). No oat β-glucan or selenium-enriched yeast was added.

[0082] β-glucan group (BG1 group): Based on the BG0 group formula, add 0.75% oat β-glucan (molecular weight 600kDa, purity 75%), and the other ingredients are the same.

[0083] Before the experiment, each pig fasted for 12 hours, and an indwelling needle was placed in the jugular vein. The pigs were fed a quantitative amount of compound feed at 2.75% of their body weight. After feeding, free access to feed was restricted for 1 hour to ensure that the feed intake of each pig was basically the same. After that, the pigs were allowed free access to water.

[0084] 3. Experimental conditions Blood collection time points: before feeding (0 h) and 0.5 h, 1 h, 2 h, 4 h, 6 h, 8 h, 12 h and 24 h after feeding, a total of 9 time points. Each time, 5 mL of jugular vein blood was collected, anticoagulated with EDTA, centrifuged at 3000 rpm for 10 min to separate plasma, stored in an ice bath, and the test was completed within 24 h.

[0085] 4. Experimental Procedure (1) Lipids were extracted from plasma samples by the Folch method (chloroform / methanol volume ratio 2:1), dried by nitrogen, redissolved in methanol, filtered through a 0.22 μm filter membrane, and then detected by HPLC.

[0086] (2) The HPLC conditions were the same as those in Experiment 1 (C18 column, acetonitrile / water 85:15, 233 nm). The concentration of c-9, t-11 CLA in plasma was quantified by external standard method (unit: μg / mL plasma).

[0087] (3) Plot the changes in plasma CLA concentration with time after feeding for the two groups, and calculate the peak concentration (Cmax), time to peak (Tmax), and area under the curve from 0 to 24 h (AUC0-24, trapezoidal method).

[0088] 5. Experimental Results Table 2. Plasma c-9 and t-11 CLA concentrations (μg / mL, mean ± standard deviation, n=6) at different time points after feed intake in the two groups of fattening pigs

[0089] Figure 2 Line graphs showing the changes in plasma c-9,t-11 CLA concentration over time in two groups of fattening pigs after feeding.

[0090] 6. Analysis and Summary In the BG0 group (without β-glucan), the plasma CLA concentration reached a peak of 6.85 μg / mL 2 h after feeding, and then rapidly declined, with AUC0-24 at 46.3 μg·h / mL within 24 h. In the BG1 group (with 0.75% β-glucan), the peak concentration decreased to 5.03 μg / mL, but Tmax was delayed to 4 h, and the absorption plateau period was prolonged (plasma concentration remained at 4.1-5.0 μg / mL from 4 h to 8 h). AUC0-24 increased to 71.1 μg·h / mL, which was 53.6% higher than that of the BG0 group (calculated using the trapezoidal method).

[0091] The above results demonstrate that oat β-glucan with a molecular weight of 600 kDa effectively forms a high-viscosity gel network in the small intestine of fattening pigs, reducing the peak absorption of CLA, prolonging the effective concentration maintenance time, and changing the CLA absorption mode from rapid concentrated type to continuous sustained release type. It can maintain a high plasma CLA level in fattening pigs throughout multiple feeding cycles throughout the day, which is beneficial for CLA to exert a continuous retargeting regulatory effect on adipose tissue.

[0092] Experiment 3: Verification of the protection of the structural integrity of CLA activity in vivo by organic selenium in maintaining GSH-Px activity 1. Experimental Objective To verify whether the organic selenium provided by selenomethionine-enriched yeast can inhibit lipid peroxidation in muscle tissue by maintaining the intact catalytic function of the glutathione peroxidase (GSH-Px) active site, protect the conjugated double bond structure of c-9,t-11 CLA, and allow more active CLA to remain in the target tissue in an undegraded form.

[0093] 2. Preparation of experimental samples Twenty-four fattening pigs weighing 60 kg were selected and randomly divided into four groups of six pigs each. They were fed this diet until slaughter (final weight approximately 110 kg). The feed formulation for each group was as follows: Blank control group (CON group): corn-soybean meal basal diet, without any functional additives.

[0094] CLA Group Only: Fermented safflower seed powder (prepared according to Example 1, HPLC measured c-9,t-11 CLA content 7.0 g / 100 g) was added to the basal diet at an amount of 14.3 g / 100 g, so that the c-9,t-11 CLA content in the dry matter of the compound feed was 1.0%; no β-glucan or selenium-enriched yeast was added.

[0095] Selenium-only group (Se group): The basal diet is supplemented with selenomethionine-enriched selenium yeast (total selenium content 2500 mgSe / kg), with an addition amount of 0.16 g / kg (target Se content 0.4 mg Se / kg); no fermented safflower seed powder or β-glucan is added.

[0096] Full group: formulated according to Example 1, the dry matter of the compound feed contains 1.0% c-9,t-11 type CLA, 0.75% β-glucan, and 0.4 mg Se / kg organic selenium.

[0097] 3. Experimental conditions Feeding amount: Feed 2.75% of body weight daily, twice a day, morning and evening, with free access to water; collect samples of the longissimus dorsi muscle (lumbar segment) within 30 minutes after slaughter, quick-freeze with liquid nitrogen, and then transfer to an ultra-low temperature freezer (−80℃) for storage for testing.

[0098] 4. Experimental Procedure (1) GSH-Px activity detection: Take 0.1 g of muscle tissue, grind it into a homogenate in an ice bath, dilute it with PBS (pH 7.4) to a mass-volume concentration of 1%, centrifuge at 5000 rpm for 10 min, take the supernatant and measure the GSH-Px activity at 412 nm according to the DTNB method (5,5' dithiobis(2-nitrobenzoic acid) color development), expressed as U / mg protein (1 U is defined as the amount of enzyme required to catalyze 1 nmol GSH oxidation per minute).

[0099] (2) Malondialdehyde (MDA) content detection: Take 0.1 g of muscle tissue, prepare the supernatant in the same way, and then determine the MDA content at 532 nm according to the TBA method (thiobarbituric acid reaction). The content is expressed as nmol / mg protein. MDA is the final product of the lipid peroxidation chain reaction and reflects the degree of lipid peroxidation in tissue.

[0100] (3) Detection of CLA content in muscle tissue: Take 0.5 g of freeze-dried muscle powder, extract total lipids by acid hydrolysis, saponify and quantify the content of c-9, t-11 type CLA and t-10, c-12 type CLA by HPLC, expressed as mg / g fresh weight.

[0101] 5. Experimental Results Table 3. Results of GSH-Px activity, MDA content and CLA content in the longissimus dorsi muscle of fattening pigs in each group (mean ± standard deviation, n=6)

[0102] Figures 3-5 Bar charts (including error bars) showing the GSH-Px activity, MDA content, and c-9,t-11 CLA content in muscle tissue of each group.

[0103] 6. Analysis and Summary The GSH-Px activities of the CON group and the CLA group were similar (43.2 and 44.8 U / mg prot, respectively), indicating that the addition of CLA alone had no significant effect on GSH-Px activity; the GSH-Px activities of the Se group and the FULL group increased to 76.5 and 88.3 U / mg prot, respectively, proving that organic selenium is an essential supply for maintaining the complete catalytic activity of GSH-Px.

[0104] MDA content decreased with increasing GSH-Px activity. The MDA content in the FULL group (1.24 nmol / mg prot) was 47.9% lower than that in the CON group (2.38 nmol / mg prot), indicating a significant reduction in lipid peroxidation. Regarding the c-9,t-11 CLA content in muscle, the CLA group (0.65 mg / g fresh weight) was significantly higher than that in the CON group (0.11 mg / g fresh weight), but its active conformation ratio (2.3) was lower than that of the CON group (5.5). This indicates that in the absence of selenium protection, feed-derived CLA underwent partial degradation and transformation in tissues due to lipid peroxidation damage. The FULL group achieved a c-9,t-11 CLA content of 0.92 mg / g fresh weight and an active conformation ratio of 7.1, while also obtaining the highest GSH-Px activity and the lowest MDA level.

[0105] The above results demonstrate that organic selenium effectively inhibits lipid peroxidation in muscle tissue by maintaining the complete catalytic activity of GSH-Px, protects the conjugated double bonds of CLA from oxidative degradation, and allows more c-9,t-11 type CLA to remain in the target tissue in an active form and exert its lipid repositioning regulation function.

[0106] Experiment 4: Verification of the effect of the compound feed of this invention on improving the overall slaughter performance of fattening pigs 1. Experimental Objective Using a blank control and chemically synthesized CLA additive as references, the improvement effect of the compound feed of this invention (a three-component compound of rosemary-fermented safflower seed powder, oat β-glucan, and selenomethionine-type selenium-enriched yeast) on comprehensive slaughter performance indicators such as backfat thickness, intramuscular fat content, eye muscle area, and feed conversion ratio of fattening pigs was verified. The distribution morphology of intramuscular fat was observed by staining muscle tissue sections.

[0107] 2. Preparation of experimental samples Sixty 60-kg fattening pigs (Landrace × Large White × Duroc) were selected and randomly divided into 3 groups of 20 pigs each. They were fed the following formulated feeds until slaughter (final weight approximately 110 kg): Blank control group (CON group): corn-soybean meal basal diet, without any functional additives.

[0108] Synthetic CLA group (SCLA group): Commercially available c-9, t-11 type CLA (purity ≥95%) synthesized by alkali isomerization is added to the basal diet at a rate of 1.0% of the dry matter of the compound feed; no other functional additives are added.

[0109] The full group of this invention was formulated according to Example 1. The dry matter of the compound feed contained 1.0% c-9,t-11 type CLA (derived from fermented safflower seed powder, HPLC measured CLA content 7.0 g / 100 g, added amount 14.3 g / 100 g), 0.75% oat β-glucan (molecular weight 600 kDa, purity 75%), and 0.4 mg Se / kg organic selenium (selenomethionine-enriched selenium yeast, total selenium content 2500 mg Se / kg, added amount 0.16 g / kg).

[0110] Each group was fed 2.75% of their body weight, twice a day, morning and evening, with free access to water. They were fed continuously until they reached a body weight of 110 kg before slaughter.

[0111] 3. Experimental conditions Before slaughter, the animals were fasted and abstaining from water for 12 hours. Slaughtering was carried out in accordance with the slaughtering operation procedure of GB / T 17236. After slaughter, the carcass was cooled (2°C) for 24 hours. Backfat and longissimus dorsi muscle samples were taken from the last rib (between the 13th and 14th ribs, 6 cm away from the back midline) for various index tests, consistent with the location of ultrasound measurement of live backfat in step 4(1).

[0112] 4. Experimental Procedure (1) Backfat thickness: The backfat thickness (mm) of the live animal was measured in real time at 6 cm away from the back midline at the last rib using an ultrasonic measuring instrument, and verified by vernier calipers after slaughter.

[0113] (2) Intramuscular fat content: Take about 50 g of the longissimus dorsi muscle, freeze-dry it, and then determine the fat content by Soxhlet extraction (ether as solvent, reflux extraction for 6 h). The fat content is expressed as dry matter percentage (%) and converted to fresh weight.

[0114] (3) Area of ​​the eye muscles: On the cross section of the muscle between the 13th and 14th ribs, cover the cross section of the longissimus dorsi muscle with tracing paper, draw the outline, and then calculate the area (cm²) using an image analyzer.

[0115] (4) Feed conversion ratio (F / G): Calculated by dividing the total feed intake during the entire fattening period (60 kg to slaughter) by the total weight gain.

[0116] (5) Muscle shear force: Take a block of the longissimus dorsi muscle (1 cm × 1 cm × 3 cm), heat it in a 75°C water bath to a core temperature of 70°C, and after cooling, measure the maximum shear force (kgf) using a Warner-Bratzler shear apparatus.

[0117] (6) Oil Red O staining of muscle tissue: Frozen sections of the longissimus dorsi muscle (8 μm thick, Leica cryostat microtome) were taken, and Oil Red O staining solution (prepared with isopropanol, 0.5% by volume) was used to stain at room temperature for 15 min. Cell nuclei were counterstained with hematoxylin, and the sections were mounted with glycerol gelatin. Cross-sectional images of the muscle were taken under an inverted optical microscope in 200x bright field mode to observe the distribution density and size of intramuscular fat droplets.

[0118] 5. Experimental Results Table 4. Results of comprehensive slaughter performance indicators of three groups of fattening pigs (mean ± standard deviation, n=20)

[0119] Figure 6 A bar chart comparing the backfat thickness of three groups of fattening pigs.

[0120] Figure 7 A bar chart comparing the intramuscular fat content of three groups of fattening pigs.

[0121] Figure 8 A bar chart comparing the eye muscle area of ​​three groups of fattening pigs.

[0122] Figure 9 A bar chart comparing the feed conversion rates of three groups of fattening pigs.

[0123] Figure 10 Images of Oil Red O stained tissue sections (200x magnification) of the longissimus dorsi muscle of three groups of fattening pigs.

[0124] 6. Analysis and Summary Compared with the CON group, the FULL group showed a decrease in backfat thickness from 17.3 mm to 13.2 mm (a reduction of 23.7%, reaching the standard range of 12-15 mm for high-quality carcasses), an increase in intramuscular fat content from 1.75% to 2.37% (an increase of 35.4%), an increase in eye muscle area of ​​10.1%, a decrease in feed conversion ratio from 2.85 to 2.73 (an improvement of 4.2%), a decrease in muscle shear force of 13.8%, and improved meat tenderness.

[0125] The SCLA group's indicators were between those of the CON and FULL groups, indicating that, with the same amount of CLA added, the comprehensive approach of this invention, which combines fermented plant-derived CLA with β-glucan slow release and organic selenium protection, is superior to simply using chemically synthesized CLA in terms of backfat control, intramuscular fat enhancement, and meat quality improvement.

[0126] Oil Red O staining images visually show that the distribution density and size of red fat droplets in the cross-section of the muscle in the FULL group are significantly higher than those in the CON group. This is corroborated by the quantitative detection results of intramuscular fat content, proving that the compound feed of this invention has achieved effective redirection of subcutaneous fat to intramuscular fat, and has a significant effect on improving overall slaughter performance.

[0127] The embodiments of the present invention have been described above. However, the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make more equivalent embodiments under the guidance of the present embodiments, and all of them are within the protection scope of the present embodiments.

Claims

1. A method for preparing a compound feed for improving slaughter performance of fattening pigs, characterized in that, Includes the following steps: Step 1, Preparation of Hugo fermented safflower seed powder: Safflower seeds with a linoleic acid content of not less than 72% are crushed to a particle size of 2-4 mm. 1.5-3.0 g of rosemary extract containing rosmarinic acid is added to every 100 g of crushed safflower seeds. After mixing evenly, Bacillus subtilis with linoleic acid isomerase activity and the ability to secrete cellulase is inoculated. The substrate moisture content is adjusted to 50%-60%. Aerobic solid-state fermentation is carried out at 35-40℃ for 48-72 h, with the material turned over every 12 h. The fermentation product is dried at a temperature not exceeding 60℃ until the moisture content is not higher than 12% and then pulverized to obtain Hugo fermented safflower seed powder. Step 2, Formulate compound feed: Add fermented safflower seed powder, oat β-glucan with a molecular weight of not less than 500 kDa, and organic selenium to the basal diet of fattening pigs, mix evenly, wherein the content of c-9,t-11 type conjugated linoleic acid in the dry matter of the compound feed is 0.8% to 1.2%, the amount of oat β-glucan added is 0.5% to 1.0% of the dry matter of the compound feed, and the amount of organic selenium added is 0.3 to 0.5 mg Se / kg of dry matter of the compound feed; Step 3, feeding: From the time the fattening pigs reach a weight of 60 kg until slaughter, feed them the compound feed obtained in Step 2 continuously at a weight of 2.5% to 3.0% of their body weight, and provide them with free access to water.

2. The method of preparing a feed mixture for improving slaughter performance of growing-finisher pigs according to claim 1, characterized by, The linoleic acid content of the safflower seed powder was confirmed by batch-by-batch testing using gas chromatography.

3. The method for preparing compound feed to improve the slaughter performance of fattening pigs according to claim 1 or 2, characterized in that, The rosemary extract mentioned in step one is a rosemary ethanol extract, and the extraction solvent is a food-grade ethanol solution with a volume fraction of 50% to 75%. The quality standard of the rosemary extract is: the content of rosmarinic acid is not less than 15% and the content of carrageenan is not less than 5%, both on a dry weight basis.

4. The method for preparing compound feed to improve the slaughter performance of fattening pigs according to claim 1, characterized in that, The Bacillus subtilis strain described in step one was pre-screened and confirmed to meet the following conditions: under the conditions of fermentation temperature of 35-40℃, substrate moisture content of 50%-60%, and fermentation time of 48-72 h, the conversion rate of c-9,t-11 type conjugated linoleic acid to linoleic acid was not less than 10%, and the cellulase filter paper enzyme activity was not less than 0.5 U / mL of culture medium.

5. The method for preparing compound feed to improve the slaughter performance of fattening pigs according to claim 1 or 4, characterized in that, The inoculation amount of the Bacillus subtilis in step one is 1 x 10 7 ~ 1 x 10 8 CFU / g substrate.

6. The method for preparing compound feed to improve the slaughter performance of fattening pigs according to claim 1, characterized in that, The purity of the oat β-glucan mentioned in step two is not less than 70%.

7. The method for preparing compound feed to improve the slaughter performance of fattening pigs according to claim 1, characterized in that, The organic selenium source mentioned in step two is selenomethionine-type selenium-enriched yeast, which is obtained by culturing Saccharomyces cerevisiae in a selenium-enriched culture medium. The quality standard is: the total selenium content is not less than 2000 mg Se / kg of yeast dry product, of which the proportion of organic selenium in the form of selenomethionine is not less than 60% of the total selenium content, and the inorganic selenium residue is not more than 10%.

8. The method for preparing compound feed to improve the slaughter performance of fattening pigs according to claim 7, characterized in that, The actual amount of selenium-enriched yeast added is calculated using the following formula: Selenium-enriched yeast addition amount = Target Se addition amount ÷ Actual total selenium content of selenium-enriched yeast product × 1000; The target Se addition amount is 0.3–0.5 mg Se / kg; The total selenium content of the selenium-enriched yeast products must be determined batch by batch using ICP-MS or atomic fluorescence spectrometry.

9. A compound feed prepared by the method for improving the slaughter performance of fattening pigs according to any one of claims 1-8, characterized in that, The compound feed includes a basal diet for fattening pigs and the following three functional additives: The fermented safflower seed powder is made by crushing safflower seeds with a linoleic acid content of not less than 70% to a particle size of 2-4 mm, mixing them evenly with rosemary extract containing rosmarinic acid at a ratio of 1.5-3.0 g of rosemary extract per 100 g of crushed safflower seeds, inoculating with Bacillus subtilis with linoleic acid isomerase activity and capable of secreting cellulase, and then carrying out aerobic solid-state fermentation at 35-40℃ for 48-72 h. After drying at a temperature not exceeding 60℃ until the moisture content is not higher than 12%, the powder is then pulverized. The amount added is based on the C-9,T-11 type conjugated linoleic acid content in the dry matter of the compound feed reaching 0.8%-1.2%. Oat β-glucan, with a molecular weight of not less than 500 kDa and a purity of not less than 70%, is added at a rate of 0.5% to 1.0% of the dry matter in the compound feed. Organic selenium, added at a rate of 0.3–0.5 mg Se / kg dry matter in compound feed.

10. A method for feeding the compound feed for improving the slaughter performance of fattening pigs as described in claim 9, characterized in that, Start feeding when the fattening pigs reach a weight of 60 kg and continue feeding until slaughter; feed at 2.5% to 3.0% of the fattening pigs' body weight daily, twice a day, morning and evening, with free access to water.

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