Feed for pork rich in omega-3 polyunsaturated fatty acids and preparation method of feed

Abstract

The invention discloses a feed for pork enriched with omega-3 polyunsaturated fatty acids and a preparation method of the feed. The core of the feed is a strain-prebiotics-plant polyphenol synergistic interaction feed system. The feed comprises the following components in parts by weight: 1-5 parts of an intestinal adaptive functional strain preparation, 2-8 parts of an omega-3 precursor in which alpha-linolenic acid is 45%-60%, 1-4 parts of a prebiotic compound and 0.1-0.3 part of plant polyphenol. Through a closed-loop mechanism that prebiotics promote strain colonization, strains convert alpha-linolenic acid into eicosapentaenoic acid and docosahexaenoic acid, strain metabolites activate polyphenol to resist oxidation and polyphenol promotes omega-3 muscle transport, the conversion rate of alpha-linolenic acid is 38%-45%, the oxidation rate of pork omega-3 is reduced by 40%-50%, and the conversion rate of alpha-linolenic acid is reduced by 40%-50%. The proportion of eicosapentaenoic acid and docosahexaenoic acid in the muscle is 65%-75%; and the enzyme activity of the strain can be optimized through a temperature response promoter, the conversion efficiency is further improved by 15-20%, the scheme realizes multi-effect accurate regulation and control, and the application prospect is wide.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of livestock feed processing, and particularly relates to a feed for enriching pork with omega-3 polyunsaturated fatty acids and a preparation method thereof. BACKGROUND

[0002] Omega-3 polyunsaturated fatty acids are essential for human health, but the human body cannot synthesize them and needs to obtain them from food. Pork, as a livestock product with high consumption, has a low content of omega-3, and the enrichment of omega-3 through feed regulation has become a research hotspot. The existing technology directly adds fish oil and other eicosapentaenoic acid / docosahexaenoic acid (EPA / DHA) raw materials, which has the problems of high cost, easy oxidation, and easy influence on flavor. Or only alpha-linolenic acid (ALA) precursors are added, which relies on the animal's own conversion enzyme system, and the conversion rate is less than 20%. Although some studies have tried to use probiotics to assist in conversion, ordinary strains have weak intestinal colonization ability, low delta-6 fatty acid dehydrogenase activity, and lack of antioxidant synergistic mechanisms, resulting in more than 30% of the omega-3 oxidation loss in muscle. Therefore, developing a low-cost, high-conversion-efficiency, and omega-3 oxidation-inhibiting feed system is a key requirement for efficient enrichment of pork omega-3. SUMMARY

[0003] In view of the above problems, the application provides a feed for enriching pork with omega-3 polyunsaturated fatty acids and a preparation method thereof. The feed has the characteristics of high omega-3 conversion efficiency, low cost, and good antioxidant effect, and performs well in terms of strain intestinal colonization ability, feed stability, pork flavor retention, and the like, and can meet the production and application requirements of high-quality omega-3 enriched pork in large-scale breeding.

[0004] In order to achieve the above-mentioned purposes, the application adopts the following technical solutions: A feed for enriching pork with omega-3 polyunsaturated fatty acids, the feed is prepared from the following raw materials by weight: 1-5 parts of an intestinal adaptive functional strain preparation, 2-8 parts of an omega-3 precursor, 1-4 parts of a prebiotic compound, 0.1-0.3 parts of plant polyphenols, and 70-85 parts of a basic feed; The intestinal adaptive functional strain preparation contains Lactobacillus acidophilus or Bifidobacterium longum with delta-6 fatty acid dehydrogenase activity, and the viable bacterial count is 10 9 -10 10 CFU / g, and the survival rate is 80%-90% under the condition of pH 2.0-3.0 and 75%-85% under the condition of 0.3%-0.5% bile salt; the content of alpha-linolenic acid in the omega-3 precursor is 45%-60%; and the prebiotic compound is a compound of fructooligosaccharides and inulin at a weight ratio of 1:1.

[0005] Preferably, the Lactobacillus acidophilus with the Delta 6 fatty acid dehydrogenase activity is obtained by screening the Lactobacillus delbrueckii alpha-linolenic acid-containing medium, the screening condition is 37 DEG C anaerobic culture for 48-72 h, and the Delta 6 fatty acid dehydrogenase activity of the strain is 50-70 U / mL.

[0006] Preferably, the omega-3 precursor is selected from one or more of linseed powder, linseed oil and perilla seed oil.

[0007] Preferably, the plant polyphenol is selected from one or more of green tea polyphenol, rosemary polyphenol, grape seed polyphenol, tea polyphenol and olive polyphenol, and the redox activity is 8-12 U / mg.

[0008] Preferably, the intestinal adaptive functional strain is a recombinant strain, the Delta 6 fatty acid dehydrogenase gene of the recombinant strain is connected with a 37 DEG C inducible temperature response promoter, and the enzyme activity of the strain is kept at a low level during feed storage, and the enzyme activity is increased to 60-70 U / mL after entering the pig intestine, and the conversion efficiency is increased by 15%-20%.

[0009] Preferably, the preparation method of the feed for enriching omega-3 polyunsaturated fatty acid pig meat comprises the following steps: S1, weighing the base feed, intestinal adaptive functional strain preparation, omega-3 precursor, prebiotic compound and plant polyphenol; S2, uniformly mixing the base feed, omega-3 precursor, prebiotic compound and plant polyphenol, granulating, and the granulating temperature is 70-80 DEG C and is kept for 5-15 min; S3, after the granulating product is cooled to 25-40 DEG C, the intestinal adaptive functional strain preparation is added, and stirred for 15-30 min to be uniform, and the feed is obtained.

[0010] Preferably, the base feed is composed of 60-70 parts of corn, 15-25 parts of soybean meal and 3-8 parts of bran by weight.

[0011] Preferably, the intestinal adaptive functional strain preparation is prepared by freeze-drying method, the freeze-drying protective agent is a compound of 10%-15% skimmed milk powder and 5%-8% trehalose, and the moisture content after freeze-drying is 2-5%.

[0012] The beneficial effects of the present application are: The feed prepared by the application has excellent ω-3 conversion enrichment effect, the conversion efficiency of ALA to EPA / DHA is increased by 15%-20%, and the inhibition rate of the feed to intestinal pathogenic bacteria is greater than 90%, and the feed has good intestinal regulation effect; the feed also improves the nutritional synergistic performance, the symbiotic system formed by the functional strain and the prebiotic can promote the balance of intestinal flora, and enhance the digestion and absorption capacity and growth performance of pigs; the antioxidant synergistic system formed by the plant polyphenol in the feed and the ω-3 precursor is stable, and can effectively inhibit the oxidative degradation of ω-3 in the processing and storage process. The addition of the intestinal adaptive strain further improves the colonization rate of the strain in the intestinal tract, improves the continuous stability of enzyme activity, and shows excellent ω-3 enrichment and breeding application performance of the whole feed. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, illustrate the application together with the embodiments thereof, and explain the application without limiting the application.

[0014] Figure 1 The comparative line graph of the viable cell count and enzyme activity of different sample strain preparations of the application; Figure 2 The comparative line graph of the ω-3 content and ω-3 oxidation loss rate in pork of different samples of the application. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below in combination with the embodiments of the application. Based on the embodiments of the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0016] Embodiment 1: The feed for enriching ω-3 polyunsaturated fatty acid pork in the embodiment 1 is prepared from the following raw materials by weight: Intestinal adaptive functional strain preparation: 3 parts of Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity, ω-3 precursor: 5 parts of flaxseed oil, prebiotic compound: 2 parts of fructooligosaccharide and inulin with a mass ratio of 1:1, plant polyphenol: 0.2 parts of green tea polyphenol, base feed: 79.8 parts; The preparation method of the feed for enriching ω-3 polyunsaturated fatty acid pork in the embodiment is as follows: S1, inoculate Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity into MRS medium containing α-linolenic acid, and cultivate anaerobically at 37℃ for 60 h to obtain a bacterial liquid, the enzyme activity of the bacterial liquid is 60 U / mL, and the viable cell count reaches 8×10 10CFU / mL; S2, 12% skimmed milk powder and 6% trehalose were mixed to prepare a protective agent, and then the protective agent was mixed with the bacterial solution at a volume ratio of 1:1. After uniform mixing, the mixture was pre-frozen at -40℃ for 2 h and vacuum freeze-dried at 0.01 mbar for 12 h to obtain a final product with a viable bacterial count of 5×10 9 CFU / g, and a moisture content of 3% of the intestinal adaptive functional strain preparation; S3, the base feed, ω-3 precursor, prebiotic compound, and plant polyphenol were weighed and put into a mixer, stirred at a speed of 1500 rpm for 15 min until uniform, and then sent to a granulator. The granulation temperature was set to 75℃, the die hole diameter was 3 mm, and the granulation process was kept for 10 min. S4, the granulation product was naturally cooled to 30℃, and the intestinal adaptive functional strain preparation was added and transferred into a low-speed mixer. The mixture was stirred at a speed of 500 rpm for 20 min until uniform, and the final feed was obtained.

[0017] Example 2: The feed for enriching ω-3 polyunsaturated fatty acid pork in this example 2 was prepared from the following raw materials by weight: Intestinal adaptive functional strain preparation: Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity 1 part, ω-3 precursor: flaxseed oil 5 parts, prebiotic compound: fructooligosaccharide and inulin at a mass ratio of 1:1 2 parts, plant polyphenol: green tea polyphenol 0.2 parts, base feed: 81.8 parts; The preparation method of the feed for enriching ω-3 polyunsaturated fatty acid pork in this example was the same as that in example 1.

[0018] Example 3: The feed for enriching ω-3 polyunsaturated fatty acid pork in this example 3 was prepared from the following raw materials by weight: Intestinal adaptive functional strain preparation: Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity 3 parts, ω-3 precursor: flaxseed oil 5 parts, prebiotic compound: fructooligosaccharide and inulin at a mass ratio of 1:1 2 parts, plant polyphenol: rosemary polyphenol 0.2 parts, base feed: 79.8 parts; The preparation method of the feed for enriching ω-3 polyunsaturated fatty acid pork in this example was the same as that in example 1.

[0019] Comparative Example 1: The feed of this comparative example 1 was prepared from the following raw materials by weight: Intestinal adaptive functional strain preparation: Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity 0 parts, ω-3 precursor: flaxseed oil 5 parts, prebiotic compound: oligofructose and inulin at a mass ratio of 1:1 2 parts, plant polyphenol: green tea polyphenol 0.2 parts, basic feed: 82.8 parts; The preparation method of the feed of the present comparative example is the same as that of Example 1.

[0020] Comparative Example 2: The feed of the present comparative example 2 is prepared from the following raw materials by weight: Intestinal adaptive functional strain preparation: Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity 3 parts, ω-3 precursor: flaxseed oil 5 parts, prebiotic compound: oligofructose and inulin at a mass ratio of 1:1 0 parts, plant polyphenol: green tea polyphenol 0.2 parts, basic feed: 81.8 parts; The preparation method of the feed of the present comparative example is the same as that of Example 1.

[0021] Comparative Example 3: The feed of the present comparative example 3 is prepared from the following raw materials by weight: Intestinal adaptive functional strain preparation: Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity 3 parts, ω-3 precursor: flaxseed oil 5 parts, prebiotic compound: oligofructose and inulin at a mass ratio of 1:1 2 parts, plant polyphenol: green tea polyphenol 0 parts, basic feed: 80 parts; The preparation method of the feed of the present comparative example is the same as that of Example 1.

[0022] Comparative Example 4: The feed of the present comparative example 4 is prepared from the following raw materials by weight: Intestinal adaptive functional strain preparation: Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity 3 parts, ω-3 precursor: flaxseed oil 5 parts, prebiotic compound: oligofructose and inulin at a mass ratio of 1:1 2 parts, plant polyphenol: green tea polyphenol 0.2 parts, basic feed: 79.8 parts; The preparation method of the feed of the present comparative example is the same as that of Example 1.

[0023] Performance test 1. Key performance test of strain preparation (1) Viable count test Take 1 g of intestinal adaptive functional strain preparation, and dilute with sterile physiological saline to 10 -9 Concentration, take 0.1 mL of the diluent and spread on MRS agar medium, incubate at 37℃ anaerobically for 48 h, count the number of colonies, and calculate the viable count (CFU / g).

[0024] (2) Δ6 fatty acid dehydrogenase activity determination The high performance liquid chromatography (HPLC) was used to take 1 mL of the bacterial liquid of the strain, centrifuge to collect the bacterial body and break it, add the α-linolenic acid substrate to react for 30 min, then determine the content of the reaction product (γ-linolenic acid), and calculate the enzyme activity (U / mL, 1 U is defined as the amount of enzyme that catalyzes 1 μmol of product per minute).

[0025] Table 1: Data table of viable cell count and activity determination of each sample

[0026] (3) Intestinal tolerance test ① pH tolerance: the strain preparation was diluted with artificial gastric juice at pH 2.0, 2.5 and 3.0, and incubated at 37°C for 2 h, then the survival rate of viable cells was determined; ② bile salt tolerance: the strain preparation was diluted with artificial intestinal juice containing 0.3%, 0.4% and 0.5% bile salt, and incubated at 37°C for 4 h, then the survival rate of viable cells was determined.

[0027] Table 2: Data table of viable cell survival rate of different samples under different conditions

[0028] (4) Preparation stability test ① Moisture content: the moisture content of the strain preparation after freeze-drying was directly determined by Karl Fischer method; ② Storage stability: the preparation was stored at 25°C and relative humidity of 60% for 3 months, and the viable cell count and enzyme activity retention rate were determined every month.

[0029] Table 3: Data table of preparation moisture content test of different samples

[0030] Table 4: Data table of viable cell count test of different samples stored for different time (×10 9 CFU / g)

[0031] Table 5: Data table of enzyme activity retention rate test of different samples stored for different time

[0032] From the above data, it can be concluded that: (1) The viable cell count of the strain preparation of Examples 1-3 and Comparative Examples 2-3 is 4.8×10 9 -5.2×10 9CFU / g, and the Δ6 fatty acid dehydrogenase activity was 58-62 U / mL; the activity of the comparative example 4 (ordinary Lactobacillus acidophilus) was <5 U / mL, verifying that "the Δ6 fatty acid dehydrogenase activity is the core functional basis of ω-3 enrichment"; (2) All samples containing functional strains showed good tolerance under the conditions of pH 2.0-3.0 (survival rate 78%-89%) and 0.3%-0.5% bile salts (survival rate 73%-84%), ensuring that the strains can successfully colonize the intestinal tract after passing through the pig digestive tract; (3) The moisture content of the preparation after freeze-drying was 2.8%-3.3%, and the viable cell count retention rate was more than 80% and the enzyme activity retention rate was 80%-86% after 3 months of storage at 25°C and 60% relative humidity, indicating that the 10%-15% skimmed milk powder and 5%-8% trehalose complex protective agent can effectively maintain the stability of the strain, meeting the storage and transportation requirements of feed; (4) The viable cell count, tolerance and storage stability of ordinary Lactobacillus acidophilus were not significantly different from those of the functional strain group, but due to the lack of target enzyme activity, it cannot achieve efficient conversion of ω-3 precursors, further demonstrating the specific advantage of the functional strain.

[0033] 2. Core effect test of feed and pork (1) Determination of ω-3 polyunsaturated fatty acid content in pork Select the feed of examples 1-3 and comparative examples 1-4, and feed (60±2) kg of healthy fattening pigs (10 pigs per group), respectively, for 60 days. After slaughter, 5 g of longissimus dorsi muscle was taken, the fat was extracted by Soxhlet extraction method, and the ω-3 total content (mg / 100g) was determined by gas chromatography-mass spectrometry (GC-MS) after methyl esterification treatment.

[0034] (2) Intestinal strain colonization rate determination After the feeding period, 3 pigs were randomly selected from each group, and 1 g of cecal content was collected, and specific primers were used for real-time fluorescent quantitative PCR (qPCR) to detect the gene copy number of the functional strain, and calculate the proportion in the total intestinal flora (colonization rate %).

[0035] (3) Determination of ω-3 oxidation loss rate ① Feed storage stage: store the feed of each group at 25°C for 30 days, and determine the initial and stored ω-3 content, and calculate the loss rate; ② Pork processing stage: store the pork sample at 4°C for 7 days, and determine the initial and stored ω-3 content, and calculate the total oxidation loss rate.

[0036] Table 6 Core effect test data table of different sample feed and pork

[0037] The pork omega-3 content of examples 1-3 reached 62.3-85.6 mg / 100g, all of which exceeded the ≥50 mg / 100g standard, and example 1 was the best, with an increase of 171.7% compared with comparative example 1 without functional strains, and an increase of 143.2% compared with comparative example 4 with ordinary strains, which confirmed the high-efficiency conversion of alpha-linolenic acid by the Δ6 fatty acid dehydrogenase active strain.

[0038] Further analysis showed that the amount of functional strains directly affected the intestinal colonization rate (the colonization rate decreased from 78.5% to 61.2% and the omega-3 content decreased synchronously when the amount of example 2 was halved), and the complex prebiotics of oligofructose and inulin could significantly promote colonization (the colonization rate was only 45.3% when there was no prebiotics in comparative example 2), and plant polyphenols were the key to inhibiting oxidation (the oxidation loss rate reached 21.6% when there was no polyphenol in comparative example 3, which was much higher than the 7.9%-9.5% of the example group).

[0039] In summary, the synergistic effect of functional strains, omega-3 precursors, prebiotics, and plant polyphenols achieved the comprehensive effect of "high conversion, high colonization, and low oxidation", and the comprehensive performance of example 1 was the best.

[0040] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A feed for pork enriched with ω-3 polyunsaturated fatty acids, characterized in that, The feed is prepared from the following raw materials in parts by weight: 1-5 parts of intestinal-adapted functional bacterial strain preparation, 2-8 parts of ω-3 precursor, 1-4 parts of prebiotic compound, 0.1-0.3 parts of plant polyphenols, and 70-85 parts of basic feed; The intestinal adaptable functional bacterial strain preparation contains *Lactobacillus acidophilus* or *Bifidobacterium longum* with Δ6 fatty acid dehydrogenase activity, and the viable count is 10-1. 9 -10 10 The CFU / g of the ω-3 precursor has a survival rate of 80%-90% under pH 2.0-3.0 conditions and a survival rate of 75%-85% under 0.3%-0.5% bile salt conditions; the α-linolenic acid content in the ω-3 precursor is 45%-60%; the prebiotic compound is a mixture of fructooligosaccharides and inulin in a 1:1 weight ratio.

2. The feed for pork enriched with ω-3 polyunsaturated fatty acids according to claim 1, characterized in that, The Lactobacillus acidophilus with Δ6 fatty acid dehydrogenase activity was obtained by screening with Lactobacillus delbrueckii screening medium containing α-linolenic acid. The screening conditions were anaerobic culture at 37°C for 48-72 h, and the Δ6 fatty acid dehydrogenase activity of this strain was 50-70 U / mL.

3. The feed for enriching pork with ω-3 polyunsaturated fatty acids according to claim 1, characterized in that, The ω-3 precursor is selected from one or more of flaxseed powder, flaxseed oil and perilla seed oil.

4. The feed for enriching pork with ω-3 polyunsaturated fatty acids according to claim 1, characterized in that, The plant polyphenols are selected from one or more of green tea polyphenols, rosemary polyphenols, grape seed polyphenols, tea polyphenols, and olive polyphenols, and have an oxidation-reduction activity of 8-12 U / mg.

5. A feed for pork enriched with ω-3 polyunsaturated fatty acids according to claim 1, characterized in that, The intestinal-adaptive functional strain is a recombinant strain. The Δ6 fatty acid dehydrogenase gene of this recombinant strain is linked to a 37°C-inducible temperature-responsive promoter. The enzyme activity of this strain remains at a low level during feed storage, but increases to 60-70 U / mL after entering the pig intestine, and the conversion efficiency increases by 15%-20%.

6. A method for preparing feed for pork enriched with ω-3 polyunsaturated fatty acids according to any one of claims 1-5, characterized in that, The specific preparation steps are as follows: S1. Weigh out the basic feed, intestinal-compatible functional bacterial strain preparation, ω-3 precursor, prebiotic compound and plant polyphenols; S2. Mix the basic feed, ω-3 precursor, prebiotic compound and plant polyphenols evenly, and granulate them at a temperature of 70-80℃ for 5-15 minutes. S3. After the granulated product has cooled to 25-40℃, add the intestinal compatible functional strain preparation and stir for 15-30 minutes until uniform to obtain the feed.

7. A method for preparing feed for pork enriched with ω-3 polyunsaturated fatty acids according to claim 6, characterized in that, The basic feed consists of 60-70 parts corn, 15-25 parts soybean meal, and 3-8 parts wheat bran by weight.

8. A method for preparing feed for pork enriched with ω-3 polyunsaturated fatty acids according to claim 6, characterized in that, The intestinal adaptable functional strain preparation is prepared by freeze-drying. The freeze-drying protectant is a compound of 10%-15% skim milk powder and 5%-8% trehalose. The moisture content after freeze-drying is 2-5%.

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