Feeding method for improving growth performance of mutton sheep

Abstract

The invention discloses a feeding method for improving the growth performance of mutton sheep, and belongs to the technical field of animal feed. The core of the method is that silage miscanthus prepared by fermenting a specific compound microbial agent is used for replacing silage corn straw in mutton sheep fattening daily ration according to the weight ratio of 50%. By means of the feeding scheme, the average daily gain (about 26% higher than that of a silage corn straw group) and the dry matter feed intake of the mutton sheep can be remarkably improved, and meanwhile it is ensured that all indexes such as slaughter performance, meat quality and intestinal health are free of adverse effects. The invention provides an efficient and reliable technical scheme for developing miscanthus as an unconventional coarse feed resource and reducing the breeding cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of animal feed, in particular to a method for optimizing the feeding effect of mutton sheep during the fattening period by using silage miscanthus to replace part of silage corn stalks, as well as a feed composition produced therefrom and the application of a strain. BACKGROUND

[0002] In the large-scale mutton sheep breeding system in China, roughage is the basis of the daily diet, and its source, cost and nutritional value directly affect the breeding benefit. Silage corn stalks have become one of the main roughage sources for mutton sheep during the fattening period due to their high digestible carbohydrate content, good palatability and relatively mature silage technology. However, the stable supply of this resource faces significant challenges: first, its production is heavily dependent on the agricultural seasonality of corn planting, and supply shortages and price fluctuations often occur during the non-harvest season; second, the long-term single use of corn stalks for feeding can lead to an imbalance in nutrient supply, which has prompted the breeding industry to seek new non-grain feed resources.

[0003] Miscanthus as a perennial C4 herbaceous plant has the outstanding advantages of high biological yield (annual dry matter yield of 15-30 tons / ha), drought resistance, poor soil tolerance, low pest and disease incidence, and low planting and management costs, and can be planted as an energy crop on marginal land in many parts of China. Developing it as an animal feed is one of the important ways to realize its resource-based high-value utilization. Preliminary studies have explored the feasibility of miscanthus as roughage for ruminants, but most studies have focused on basic nutrient component analysis or palatability observation with low proportion addition, lacking in-depth research on the systematic replacement of mainstream silage feed (such as silage corn stalks) in the key fattening stage of mutton sheep, especially the comprehensive evaluation of the complete chain of "replacement ratio-growth performance-meat quality-intestinal health".

[0004] Currently, in practice, farmers who attempt to use silage miscanthus often face a dilemma: one is to add a low proportion (such as 10%-20%), which cannot substantially alleviate the dependence on silage corn stalks and has limited economic value; the other is to simply replace the full amount, which may result in decreased dry matter intake and reduced nutrient digestibility of mutton sheep due to differences in fiber structure, lignin content, and fermentable carbohydrate composition between miscanthus and corn stalks, ultimately affecting weight gain efficiency and breeding benefit. Therefore, determining an optimal replacement ratio that can maximize the use of miscanthus resources while maintaining or even improving the production performance of mutton sheep is a key technical bottleneck for successfully converting miscanthus into conventional feed for mutton sheep breeding.

[0005] The present application is proposed to solve the above-mentioned practical problems in the industry. Through a rigorous design of feeding experiments, the effects of different gradients of silage guinea grass replacing silage corn stalks on the comprehensive production of mutton sheep are systematically evaluated, aiming to determine a scientific, feasible and efficient replacement scheme, and to provide reliable technical support for reducing feed costs, ensuring mutton quality, and promoting cost reduction and sustainable development of the mutton sheep industry. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a mutton sheep feed preparation method using silage guinea grass to partially replace silage corn stalks, aiming to find the optimal replacement ratio to significantly reduce the dependence on traditional silage feed while not affecting the slaughter performance, meat quality and intestinal health of mutton sheep, and significantly improving the growth rate and feed utilization efficiency during the fattening period.

[0007] To solve the above technical problems, the present application provides the following solutions: 1. A feeding method for improving the growth performance of mutton sheep, characterized in that 30%-60% (dry matter basis) of silage corn stalks are replaced by silage guinea grass in the mutton sheep fattening diet.

[0008] 2. The silage guinea grass is preferably prepared by fermentation of a composite microbial agent of Lactobacillus plantarum LW8 (CGMCC NO. 28108) and Lactobacillus plantarum K3 (CGMCC NO. 34845), and the ratio of viable bacterial counts of the two strains is preferably 2:1, thereby obtaining silage guinea grass with excellent quality (pH≤4.0, lactic acid≥3.0%, AN / TN≤0.70%).

[0009] Through systematic animal experiments, the present application found that when the replacement ratio is 50%, the growth performance of mutton sheep appears a synergistic improvement effect, and the average daily gain is significantly increased by about 26% compared with the whole corn stalk group. Beneficial effects

[0010] By replacing silage corn stalks with high-quality silage guinea grass at a specific ratio of 50%, the present application can significantly improve the average daily gain and dry matter intake of mutton sheep, producing a non-linear synergistic effect; at the same time, this scheme has no negative impact on key slaughter performance, meat quality indicators (meat color, pH value, water holding capacity and tenderness), and intestinal barrier function (intestinal morphology and tight junction protein expression), and realizes the improvement of growth performance on the premise of ensuring mutton quality and animal health. In addition, this technology greatly improves the feeding ratio of non-grain resources guinea grass, which helps to reduce the dependence on traditional stalks for breeding, and has positive economic and ecological benefits for stabilizing feed costs and promoting sustainable agricultural development. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 Figure 3: HE staining of duodenum, jejunum and ileum of different treatment groups (Scale bar: 200 μm).

[0012] Figure 2 Figure 4: Expression level of tight junction proteins in jejunum of different treatment groups.

[0013] (A) Western blotting analysis of tight junction proteins Claudin-1 and Occludin, with β-actin as internal reference.

[0014] (B) Quantitative analysis of tight junction proteins Claudin-1 and Occludin protein expression.

[0015] Figure 3 Figure 5: Immunohistochemical analysis of tight junction proteins ZO-1, Claudin-1 and Occludin in jejunum of different treatment groups.

[0016] (A) Representative images of immunohistochemical staining showing the localization of each protein in the intestinal mucosa (Scale bar: 20 μm).

[0017] (B) Quantitative analysis of the expression intensity of each protein based on the average optical density of image analysis. DETAILED DESCRIPTION

[0018] The application will be further described in conjunction with the examples and drawings, but the scope of protection of the application is not limited thereto.

[0019] Example 1: Preparation of high-quality silage of Miscanthus sinensis 1. Raw material pretreatment: cutting during the vegetative growth period of Miscanthus sinensis (when the crude protein content is relatively high and the fiber is moderate). The Miscanthus sinensis is cut into 1.5-2.0 cm in length to facilitate compaction and fermentation. Subsequently, the water content is precisely adjusted to 65%-75%, preferably 70% by air drying or other methods. This water content range can ensure the water activity required for the activity of lactic acid bacteria, and can also avoid excessive leakage of nutrients.

[0020] 2. Inoculation of microbial agents: Lactobacillus plantarum LW8 (CCTCC NO. 28108) and Lactobacillus plantarum K3 (CCTCC NO. 34845) are compounded at a ratio of 2:1 based on viable bacterial count. The compounded microbial starter (usually mixed with an appropriate amount of sugar source such as brown sugar to provide initial fermentation substrate) is evenly inoculated on the surface of the pretreated Miscanthus sinensis raw material by spraying or spraying. The inoculation amount needs to ensure that the total effective viable bacterial count reaches a level sufficient to dominate the fermentation process. The total inoculation amount is about 1.5 x 10 8 CFU / g of fresh material.

[0021] 3. Anaerobic fermentation control: The inoculated raw material is quickly loaded into a silage container (such as a silage bag, a pit), compacted sufficiently to expel air, and strictly sealed to create a stable anaerobic environment. Subsequently, fermentation is carried out at 20-30°C in the dark, and the fermentation time lasts for 30-45 days, preferably 40 days. This temperature control range is conducive to the dominant growth of lactic acid bacteria, and sufficient fermentation time ensures the full completion of biochemical reactions and the stability of product quality.

[0022] The silage miscanthus prepared by the above method has fermentation quality and nutrient preservation reaching the following hard indicators, meeting the requirements of the present application.

[0023] pH value ≤ 4.0: indicating a strong acidic environment that can effectively inhibit harmful microorganisms. The pH value of the silage miscanthus obtained in this embodiment is 3.59.

[0024] Lactic acid content in dry matter ≥ 3.0%: indicating that homolactic fermentation is dominant and efficient. The lactic acid content in dry matter of the silage miscanthus obtained in this embodiment is 3.80%.

[0025] Ammonia nitrogen / total nitrogen (AN / TN) ratio ≤ 0.70%: indicating that protein degradation is effectively inhibited and nutrients are well preserved. The ammonia nitrogen / total nitrogen of the silage miscanthus obtained in this embodiment is 0.60%.

[0026] Crude protein (CP) content ≥ 15.0% (based on dry matter): reflecting excellent nutritional value. The crude protein content of the silage miscanthus obtained in this embodiment is 15.81%.

[0027] Example 2: Effect of different replacement ratios of silage miscanthus on the fattening effect of mutton sheep 1. Test animals and design To accurately evaluate the effect of the feeding scheme of the present application, a single-factor completely randomized design animal test was used. 36 Lvdong mutton sheep (18 male and 18 female) with good health, similar body weight (initial body weight 33.0 ± 0.7 kg), average age of about 100 days (100 ± 10.0 d), and similar genetic background were selected.

[0028] According to the completely randomized block design, the male and female sheep were evenly distributed to 3 treatment groups, 12 in each group (6 replicates, 1 male and 1 female in each replicate, a total of 2 sheep), to ensure that the "gender" variable would not interfere with the evaluation of the effect of the feed treatment. The grouping is as follows: CON group (control group): the roughage part is 100% silage corn stalks.

[0029] MS50 group (present application group): the roughage part is 50% silage corn stalks + 50% silage miscanthus (equal weight replacement) according to the present application.

[0030] MS100 group (full replacement group): the roughage part is 100% of the silage of the present application.

[0031] 2. Test feed: (1) Silage of corn stalk: as a basic control roughage, collected from the same batch of local corn stalks with consistent maturity, prepared by standardized silage process (chopping, compaction, sealing fermentation for more than 45 days) to ensure stable fermentation quality.

[0032] (2) Silage of Chinese wildrye (product of the present application): as a test roughage, prepared by the method of the present application. Specifically, during the vegetative growth period of Chinese wildrye, the Chinese wildrye is cut to 1.5-2.0 cm, and the moisture content is adjusted to about 70%. A composite inoculant (total inoculum amount is about 1.5×10 8 CFU / g of fresh material) composed of Lactobacillus plantarum LW8 (CGMCC NO. 28108) and Lactobacillus plantarum K3 (CGMCC NO. 34845) at a ratio of 2:1 is inoculated, vacuum packaged, and fermented at 25°C in the dark for 40 days. The product quality at the end of fermentation meets the requirements of the present application: pH ≤ 4.0, lactic acid content ≥ 3.0%, ammonia nitrogen / total nitrogen ≤ 0.70%.

[0033] (3) Concentrate: formulated according to the Chinese agricultural industry standard (NY / T 816-2021) for the nutritional needs of meat sheep during the fattening period, mainly composed of corn, soybean meal, bran, premix (minerals, vitamins), etc., to ensure consistent nutritional levels of daily rations.

[0034] (4) Daily ration formulation and nutritional level: Each group is mixed with the corresponding proportion of roughage (silage of corn stalk and / or silage of Chinese wildrye) and concentrate according to the same weight ratio of concentrate: roughage = 3:7 (dry matter basis) using a total mixed ration (TMR) mixer to fully mix, and three types of total mixed rations are prepared. Accurate weighing is performed during preparation to ensure that the three rations have consistent contents of main nutritional components such as digestible energy, crude protein, neutral detergent fiber, acid detergent fiber, calcium, phosphorus, etc. on a dry matter basis, to exclude the interference of nutritional level differences on the test results.

[0035] 3. Feeding management (1) Test period and site: The total test period is 60 days, including a 10-day adaptation period and a 50-day formal test period. All experimental sheep are raised in the same standardized sheep house, and the environment (temperature, humidity, ventilation) in the house is kept consistent with the conventional management of the breeding farm. Sheep are raised in groups, with 2 sheep per pen, ensuring that each sheep has sufficient space, independent feeding troughs, and waterers.

[0036] (2) Feeding and watering: The feeding method of fixed time and fixed quantity, free feeding was adopted. Freshly prepared total mixed ration (TMR) was fed at fixed time (07:00 and 17:00) every day, and the feeding amount was slightly higher than the expected feeding amount on the basis of ensuring that there was a small amount of remaining (about 5%-10%) in the trough at all times, so as to accurately record the actual feeding amount. The remaining feed of the previous day was collected and weighed every morning before feeding.

[0037] (3) Daily management: During the experiment, the routine hygiene and health management procedures of the farm were strictly implemented, including daily cleaning of manure to keep the barn clean and dry, disinfection of the feeding trough and water trough every week, regular ventilation to maintain air circulation, and daily observation of the spirit, feeding and feces of the sheep and timely treatment when abnormalities were found. In addition, no immunization or drug treatment was implemented during the experiment to avoid interference with the test results.

[0038] (4) Sample collection and data recording preparation: On the morning of the first and 50th day of the formal test period, all experimental sheep were weighed on an empty stomach (fasted for 12 hours, free drinking water), and the initial body weight (IBW) and final body weight (FBW) were recorded. The feeding amount and remaining amount of each pen were accurately recorded every day. Preparation was made for subsequent slaughter performance, meat quality and intestinal health index determination.

[0039] 4. Sample collection, index determination and data analysis (1) Growth performance index determination: Body weight and daily gain: all experimental sheep were weighed on an empty stomach in the morning of the first and 50th day of the formal test period, and the initial body weight (IBW) and final body weight (FBW) were recorded. The average daily gain (ADG, g / d) was calculated according to the following formula: ADG = (FBW - IBW) / 50.

[0040] Feed intake and feed efficiency: the feeding amount (fresh weight, kg) and remaining amount (fresh weight, kg) of each repetition (pen) were accurately recorded every day. Daily dry matter intake (DMI) was calculated by multiplying the fresh sample intake by the corresponding dry matter content of the ration (DM%). The feed to gain ratio (F / G) was calculated according to the ratio of total dry matter intake to total weight gain during the test period. The method for determining the dry matter content of feed is as follows: the sample is initially dehydrated in a 105°C oven for 15 minutes, and then weighed after drying to constant weight at 65°C.

[0041] (2) Slaughter performance and meat quality determination: After the end of the formal test period, 6 sheep close to the average weight were randomly selected from each group for slaughter and determination.

[0042] Slaughter performance: The pre-slaughter live weight, carcass weight, dressing percentage and eye muscle area were measured.

[0043] Meat quality: The longissimus dorsi muscle samples were taken from the 12th-13th rib of the left carcass, and the following indicators were measured: pH value: The pH value was measured at 45 minutes after slaughter (pH~45min~) and 24 hours (pH~24h~, after cold storage at 4℃).

[0044] Meat color: The brightness (L*), redness (a*) and yellowness (b*) values were measured using a colorimeter.

[0045] Drip loss: The meat samples were hung in a 4℃ refrigerator for 24 hours, and the percentage of weight loss was calculated.

[0046] Cooking loss: The meat samples were heated in a water bath at 80℃ until the center temperature reached 75℃, and the percentage of weight loss was calculated.

[0047] Shear force: After cooking, the meat samples were cut along the muscle fiber direction, and the maximum shear force value (N) was measured using a texture analyzer to evaluate tenderness.

[0048] (3) Intestinal health index determination Immediately after slaughter, samples were collected from the duodenum, jejunum and ileum.

[0049] Histomorphological observation (HE staining): Part of the intestinal segment was fixed with 4% paraformaldehyde, paraffin-embedded section was stained with hematoxylin-eosin (HE), and the villus height, crypt depth and mucosal structure integrity were observed under a light microscope.

[0050] Tight junction protein expression analysis: Western Blot: Total protein was extracted from the jejunum mucosa tissue, and the expression levels of Claudin-1 and Occludin proteins were determined.

[0051] Immunohistochemical method (IHC): ZO-1, Claudin-1 and Occludin proteins were immunohistochemically stained on jejunum paraffin sections, and their localization and expression intensity were observed.

[0052] (4) Data processing and analysis All data were expressed as "mean ± standard deviation". Single factor analysis of variance was performed using SPSS statistical software, and if the difference between groups was significant (P<0.05), Duncan's multiple comparison method was used for pairwise comparison. P<0.05 was used as the criterion for significant difference.

[0053] 5. Test results and analysis (1) Growth performance and slaughter performance The results of growth performance and slaughter performance determination are shown in Table 1. The average daily gain (ADG) of the MS50 group (50% replacement group) was as high as 206.00 g / d, which was significantly higher than that of the CON group (163.56 g / d) and the MS100 group (164.00 g / d) (P<0.05). This indicates that replacing corn stalk silage with 50% of the mowing grass silage has a certain synergistic effect, which increases the growth rate of mutton sheep by nearly 26%. The dry matter intake (DMI) of the MS50 group was 1551.93 g / d, which was significantly higher than that of the other two groups (increased by about 6.34% and 5.79% respectively), indicating that the feed combination has better palatability, which is one of the reasons for promoting the growth of mutton sheep. In addition, the full replacement did not show the beneficial effect of the half replacement, indicating that replacing corn stalk silage with 50% of the mowing grass silage is more conducive to mutton sheep fattening. In addition, there was no significant difference in the dressing percentage, eye muscle area and other slaughter performance indicators between the groups (P>0.05).

[0054] Table 1: Effect of mowing grass silage replacing corn stalk silage on growth performance and slaughter performance of mutton sheep

[0055] (2) Meat quality The results of meat quality determination are shown in Table 2. There was no significant difference in all meat quality indicators, including pH value, meat color, drip loss, cooking loss and shear force, between the groups (P>0.05). This indicates that replacing corn stalk silage with 50% of the mowing grass silage does not affect the eating quality of mutton.

[0056] Table 2: Effect of mowing grass silage replacing corn stalk silage on meat quality of mutton sheep (3) Intestinal health Histomorphological observation: The intestinal tissue of each group of mutton sheep was observed by hematoxylin-eosin (HE) staining ( Figure 1 ). The results showed that the mucosa structure of duodenum, jejunum and ileum of all groups was complete, the villi arranged in order, and the crypt form was normal, and no obvious pathological changes were observed, indicating that each feeding scheme did not cause adverse effects on the basic tissue structure of the intestine.

[0057] Tight junction protein expression analysis: In order to further evaluate the intestinal barrier function, the expression levels of Claudin-1 and Occludin proteins in the jejunum mucosa were detected by Western blotting ( Figure 2 ). The results showed that there was no significant difference in the expression levels of Claudin-1 and Occludin proteins between the groups. At the same time, the results of immunohistochemical staining ( Figure 3It is shown that the localization and expression intensity of tight junction proteins ZO-1, Claudin-1 and Occludin on the intestinal mucosa have no significant difference among different treatment groups, and do not change due to feed treatment. In summary, the feeding scheme (50% replacement of silage with meadow grass) does not adversely affect the expression of intestinal tight junction proteins and the physical barrier function of the intestinal tract of mutton sheep, further confirming that the scheme has good feeding safety and reliability.

[0058] In summary, the present embodiment demonstrates that high-quality silage meadow grass prepared by the method of the present application can significantly synergistically improve the average daily weight gain and feed intake of mutton sheep, while maintaining its slaughter performance, meat quality and intestinal health, by replacing 50% of the silage corn stalks in the daily ration. This scheme solves the technical bottleneck of growth performance decline caused by high replacement ratio, achieves a fattening effect of 1+1>2, breaks the bottleneck of the prior art, and provides an economic, efficient, safe and reliable roughage replacement scheme for the mutton sheep industry.

Claims

1. A feeding method for improving the growth performance of meat sheep, characterized in that, During the fattening stage of sheep, silage hay is used to partially replace silage corn stalks in the basal diet, with a replacement ratio of 30% to 60% of the total amount of silage corn stalks in the basal diet (by dry matter weight).

2. The feeding method according to claim 1, characterized in that, The proportion of silage miscanthus replacing silage corn stalks is 50% (by dry matter weight).

3. The feeding method according to claim 1 or 2, characterized in that, The silage is made from Miscanthus sinensis raw material through fermentation with a compound microbial agent, which contains Lactobacillus plantarum LW8 (CGMCC NO.28108) and Lactobacillus plantarum K3 (CGMCC NO.34845).

4. The feeding method according to claim 3, characterized in that, In the compound microbial agent, the effective viable count ratio of Lactobacillus plantarum LW8 to Lactobacillus plantarum K3 is (1.5-2.5):

1.

5. The feeding method according to claim 4, characterized in that, The effective viable count ratio of *Lactobacillus plantarum* LW8 to *Lactobacillus plantarum* K3 is 2:

1.

6. The feeding method according to any one of claims 3 to 5, characterized in that, The fermentation quality of the silage grass meets the following indicators: pH value ≤ 4.0, lactic acid content in dry matter ≥ 3.0%, and ammonia nitrogen / total nitrogen ≤ 0.70%.

7. The feeding method according to any one of claims 1 to 6, characterized in that, The basal diet is a total mixed ration (TMR), wherein the dry matter weight ratio of concentrate to roughage is 3:7, and the silage of miscanthus and silage of corn stalks together constitute all or part of the roughage.

8. A fattening feed composition for meat sheep, characterized in that, Its roughage portion includes silage miscanthus and silage corn stalks, and the silage miscanthus accounts for 30% to 60% of the total dry matter weight of the silage miscanthus and silage corn stalks.

9. The fattening feed composition for meat sheep according to claim 8, characterized in that, The silage grass accounts for 50% of the total dry matter weight of the silage grass and silage corn stalks.

10. The use of *Lactobacillus plantarum* LW8 (CGMCC NO. 28108) and *Lactobacillus plantarum* K3 (CGMCC NO. 34845) in the preparation of feed additives or fermentation agents for improving the average daily weight gain of meat sheep during the fattening period, characterized in that, The fermenting agent is used to prepare silage miscanthus, and the silage miscanthus is used to replace silage corn stalks in the daily diet of meat sheep at a ratio of 30%-60% of the dry matter weight of silage corn stalks.

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