Feed additive for improving growth performance and meat quality of mutton sheep and application thereof

Abstract

The invention belongs to the technical field of feed additives, and particularly relates to a feed additive for improving the growth performance and meat quality of mutton sheep and application of the feed additive. In order to solve the problem that the growth performance and meat quality of mutton sheep cannot be improved by adopting plant extracts as feed additives in the prior art, the invention provides a feed additive for improving the growth performance and meat quality of mutton sheep, and the feed additive comprises the following components in percentage by weight: 70-90% of chicory leavening, 5-15% of sophora flower bud extract and 5-15% of pine bark extract. According to the feed, firstly, the chicory is fermented to prepare a fermented product, the utilization rate of the chicory is increased, the sophora flower bud extract and the pine bark extract are added, an additive composed of the sophora flower bud extract, the pine bark extract and the sophora flower bud extract can be directly used as a concentrate supplement of the mutton sheep, under the synergistic effect of the sophora flower bud extract, the pine bark extract and the sophora flower bud extract, the growth performance of the mutton sheep is jointly improved, and especially the quality of mutton is remarkably improved; a new way is developed for the utilization of the chicory, and a new additive combination is provided for improving the mutton quality.

Description

Technical Field

[0001] This invention belongs to the field of feed additive technology, specifically relating to a feed additive for improving the growth performance and meat quality of sheep and its uses. Background Technology

[0002] In recent years, with the improvement of people's living standards and changes in dietary structure, the number of people consuming beef and mutton has been increasing, and the demand for high-quality beef and mutton has also been rising. However, existing beef and mutton farming mostly adopts a free-range model, resulting in slow growth and a long growth cycle, which simply cannot meet market demand.

[0003] Currently, my country also has methods for large-scale sheep farming, mainly using feed and additives specifically designed for meat sheep to improve their growth performance. These feed additives mostly consist of traditional substances that provide basic nutrients, such as protein, minerals, or vitamins. The use of these additives has greatly improved the growth performance of meat sheep, but the rate of improvement is still insufficient, especially when the growth rate of meat sheep accelerates. Maintaining good meat quality has become a new research focus in this field.

[0004] The evaluation indicators for animal meat quality mainly include meat color, tenderness, marbling, and flavor. Traditional farming methods may involve the addition of additives such as antibiotics or hormones, which can easily lead to a decline in meat quality and pose food safety risks. In recent years, plant extracts have become a research hotspot in the field of feed additives due to their natural, safe, and multifunctional characteristics.

[0005] Chicory, a perennial herbaceous plant belonging to the genus *Cichorium* in the family Asteraceae, is mainly distributed in Northwest, North, and Northeast my country. It primarily contains inulin, polyphenols, and chicoric acid, and is currently mainly used in food. There are reports of adding chicory extract and other mixed plant extracts to largemouth bass feed, showing that these extracts can synergistically activate the insulin signaling pathway in largemouth bass, promote glycolysis, inhibit gluconeogenesis, alleviate high-glucose-induced insulin resistance, and reduce glycogen accumulation in the liver. Currently, chicory is used as a forage crop in pig farming; however, fresh chicory has low nutritional value, is difficult to store, and is severely limited by seasonality. Furthermore, there are currently no mature technologies for using chicory as a feed additive, and its development is urgently needed.

[0006] Sophora japonica buds, a deciduous tree belonging to the genus Sophora in the legume family, are cultivated throughout my country. Extracts from Sophora japonica buds mainly contain flavonoids, as well as rutin and quercetin, exhibiting strong antioxidant properties. They are primarily used in the food and pharmaceutical fields. Reports of adding Sophora japonica buds to animal feed are scarce, and there are no reports of using them in sheep feed to improve meat quality.

[0007] Pine trees are one of the major tree species in my country, widely distributed throughout the country. Pine bark is an important component, rich in various functional active ingredients, such as volatile oils mainly composed of aromatic, aliphatic, and terpenoid compounds, and polyphenolic compounds mainly composed of proanthocyanidins. It also contains amino acids, polysaccharides, vitamins, and trace elements such as calcium, potassium, iron, magnesium, phosphorus, manganese, zinc, and silver, as well as other nutrients essential for life activities, giving it extremely high feed and medicinal value. Currently, studies have shown that adding pine bark extract to fattening pig feed can reduce fat deposition in pig liver and decrease muscle shear force, but has no significant effect on the cooking loss rate of pork or 24-hour pH. There are currently no reports on its impact on mutton quality.

[0008] Currently, research on using plant extracts as feed additives to improve the growth performance of sheep and enhance the quality of mutton is still relatively scarce and urgently needs to be developed. Summary of the Invention

[0009] The technical problem to be solved by this invention is: the lack of existing methods to use plant extracts as feed additives to improve the growth performance of sheep and improve the quality of mutton.

[0010] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a feed additive for improving the growth performance and meat quality of sheep is provided, the composition of which includes: 70-90% chicory fermented product, 5-15% sophora japonica extract and 5-15% pine bark extract by weight percentage.

[0011] Preferably, in the above-mentioned feed additives for improving the growth performance and meat quality of mutton sheep, the additives are composed of: 80% chicory ferment, 10% sophora japonica extract, and 10% pine bark extract by weight percentage.

[0012] Among the feed additives mentioned above that improve the growth performance and meat quality of sheep, the chicory ferment is prepared by fermenting chicory, garlic peel, and corn flour.

[0013] Furthermore, the weight ratio of chicory, garlic peel, and corn flour is 20-30:0.1-1:1-3.

[0014] Preferably, the weight ratio of chicory, garlic peel, and corn flour is 50:1:4.

[0015] Specifically, the preparation method of the chicory ferment is as follows: Weigh chicory, garlic peel and corn flour by weight, chop the chicory to 3-5cm, add garlic peel and corn flour, mix evenly, add 1-10% of the fermenting agent by weight of the substrate, seal, and ferment in the dark at 25-30℃ for 3-10 days to obtain the chicory ferment.

[0016] Furthermore, the chicory has a water content of 70-75%.

[0017] Furthermore, the fermentation agent is a mixture of Lactobacillus plantarum, Bacillus subtilis, and Aspergillus niger.

[0018] Furthermore, the viable count of the *Lactobacillus plantarum* is ≥4 × 10⁻⁶. 8 CFU / g, the viable count of the Bacillus subtilis is ≥3×10⁻⁶. 9 CFU / g, the viable count of the *Aspergillus niger* is ≥5×10⁻⁶. 9 CFU / g.

[0019] Furthermore, the ratio of viable bacteria of *Lactobacillus plantarum*, *Bacillus subtilis*, and *Aspergillus niger* is 6:1 to 3:2 to 6.

[0020] Among the above-mentioned feed additives for improving the growth performance and meat quality of sheep, the preparation method of the Sophora japonica extract is as follows: Sophora japonica flowers are crushed and sieved, added to a 70-75% ethanol solution, extracted at 80-90℃ for 1.5-3 hours, the extract is centrifuged, the supernatant is collected, filtered using a filter membrane, the filtrate is concentrated and freeze-dried to prepare the Sophora japonica extract.

[0021] Furthermore, the ratio of the sophora japonica buds to ethanol is 1:5.

[0022] Among the above-mentioned feed additives for improving the growth performance and meat quality of sheep, the preparation method of the pine bark extract is as follows: after crushing pine bark, add it to a 70-75% ethanol solution, then add 2-3% citric acid by weight of pine bark, and extract at 4-6℃ for 24-48 hours; concentrate under reduced pressure to obtain a primary concentrate, chromatographically analyze the concentrate in water to obtain a chromatographic solution, then concentrate the chromatographic solution under reduced pressure again, condense and centrifuge to obtain the pine extract.

[0023] The method of this invention first extracts proanthocyanidins from pine bark using ethanol, a highly polar extractant. The concentration of proanthocyanidins in the extract is increased by vacuum concentration and chromatography. The reconcentrated solution obtained from the second vacuum concentration is then condensed and centrifuged to remove insoluble impurities. Simultaneously, this invention adds citric acid to stabilize the anthocyanins in the pine bark extract and prevent acylation.

[0024] The present invention also provides a use of the above-mentioned feed additive for improving the growth performance and meat quality of sheep, for improving the meat quality of sheep.

[0025] The beneficial effects of this invention are as follows: This invention provides a feed additive that improves the growth performance and meat quality of mutton sheep. The main ingredients include chicory fermented product, sophora japonica extract, and pine bark extract. The chicory fermented product is obtained through a unique fermentation method of this invention, which greatly improves the palatability and utilization rate of chicory, significantly enhancing its utilization efficiency. Furthermore, this invention also adds sophora japonica extract and pine bark extract, which, through a synergistic effect, significantly improve the growth performance and meat quality of mutton sheep. This feed additive can be directly used as a concentrate supplement, partially replacing the concentrate feed for mutton sheep, providing a new supplementary feed source for mutton sheep. Detailed Implementation

[0026] This invention provides a feed additive to improve the growth performance and meat quality of sheep, comprising: by weight percentage, 70-90% chicory ferment, 5-15% sophora japonica extract, and 5-15% pine bark extract.

[0027] Preferably, in the above-mentioned feed additives for improving the growth performance and meat quality of mutton sheep, the additives are composed of: 80% chicory ferment, 10% sophora japonica extract, and 10% pine bark extract by weight percentage.

[0028] This invention primarily utilizes chicory as a raw material, preparing a chicory ferment through a special fermentation process. This ferment, combined with sophora japonica extract and pine bark extract, collectively improves the growth performance and meat quality of sheep. All raw materials selected for this invention are plant-based, widely available, and safe with no toxic side effects. Chicory is a perennial herbaceous plant belonging to the genus *Cichorium* of the Asteraceae family. It mainly contains inulin, polyphenols, chicoric acid, and other substances. Currently, there are few reports on its use in sheep feed, and even fewer reports on how to use chicory or its effects when used as feed.

[0029] In a first aspect, to fully utilize the nutrients in chicory, improve its utilization rate, and facilitate industrial production, this invention first ferments the chicory to prepare a fermented chicory product. During fermentation, due to the high water content of chicory, the inventors found that direct fermentation could not achieve good results. After repeated experiments and screening, the inventors discovered that adding garlic peels and corn flour to the chicory during fermentation could reduce the water content of the fermented material throughout the fermentation process, thereby improving the fermentation effect. Through screening, the inventors found that the fermentation effect was best when the weight ratio of chicory, garlic peels, and corn flour was 20–30:0.1–1:1–3, especially when the weight ratio was 50:1:4.

[0030] Having determined the composition of the fermentation substrate, the selection of the inoculum is equally crucial. After extensive screening, the inventors discovered the optimal combination of fermentation inoculum. The best fermentation effect was observed in chicory when a compound inoculum of *Lactobacillus plantarum*, *Bacillus subtilis*, and *Aspergillus niger* was prepared at a live cell ratio of 6:1–3:2–6.

[0031] In a second aspect, this invention incorporates Sophora japonica flower extract and pine bark extract prepared using a proprietary design method. These two extracts, to a certain extent, synergistically enhance the effects of chicory fermentation, jointly improving the growth performance of mutton sheep. The combined use of these three ingredients also improves the meat quality of the mutton.

[0032] The specific implementation of the present invention will be further explained and described below through examples, but this does not mean that the scope of protection of the present invention is limited to the scope described in the examples.

[0033] The sheep breed used in this example is the Nanchong Black Goat, which was provided by the Nanchong City Feed Station.

[0034] The *Lactobacillus plantarum*, *Bacillus subtilis*, and *Aspergillus niger* mentioned in the examples were all purchased from the China General Microbiological Culture Collection Center and activated and cultured according to conventional methods in the art until the viable count of *Lactobacillus plantarum* was ≥4 × 10⁻⁶. 8 CFU / g, viable count of Bacillus subtilis ≥3×10 9 CFU / g, viable count of Aspergillus niger ≥ 5 × 10⁻⁶ 9 CFU / g.

[0035] The remaining reagents and raw materials are all commercially available products.

[0036] Example 1: Preparation of chicory ferment using the method of the present invention

[0037] The specific operating steps are as follows:

[0038] Take fresh chicory, chop it to 3-5cm, and control the moisture content to 75%; add garlic peel and corn flour, mix well, add 5% of the fermentation agent by weight of the fermentation substrate, seal, and ferment in the dark at 30℃ for 10 days to obtain chicory ferment.

[0039] The usage of each fermentation raw material and fermentation agent in Example 1 is shown in Table 1 below.

[0040] Table 1. Amounts of fermentation substrate and inoculum used in different treatment groups

[0041] Chicory (kg) Garlic peels (kg) Corn flour (kg) Lactobacillus plantarum (CFU) Bacillus subtilis (CFU) Aspergillus niger (CFU) Experimental group 1 20 1 1 <![CDATA[6×10 9 ]]> <![CDATA[1×10 9 ]]> <![CDATA[2×10 9 ]]> Experimental group 2 20 0.1 3 <![CDATA[6×10 9 ]]> <![CDATA[3×10 9 ]]> <![CDATA[6×10 9 ]]> Experimental group 3 30 1 3 <![CDATA[6×10 9 ]]> <![CDATA[2×10 9 ]]> <![CDATA[2×10 9 ]]> Experimental group 4 30 0.1 1 <![CDATA[6×10 9 ]]> <![CDATA[3×10 9 ]]> <![CDATA[2×10 9 ]]> Experimental group 5 25 0.5 2 <![CDATA[6×10 9 ]]> <![CDATA[2×10 9 ]]> <![CDATA[4×10 9 ]]> Experimental group 6 25 1 1 <![CDATA[6×10 9 ]]> <![CDATA[2×10 9 ]]> 0 Experimental group 7 25 0 2 <![CDATA[6×10 9 ]]> <![CDATA[2×10 9 ]]> <![CDATA[4×10 9 ]]> Experimental group 8 25 2 0 0 <![CDATA[2×10 9 ]]> <![CDATA[4×10 9 ]]>

[0042] The performance of chicory fermented products prepared by different treatment methods in Example 1 was tested. The dry matter content was determined according to GB / T 6435-2014; the pH value was determined according to DB15 / T 1458-2018; the crude protein was determined according to GB / T 6432-2018; and the neutral detergent fiber was determined according to DB37 / T 2968-2017. The results of the performance index tests are shown in Table 2 below.

[0043] Table 2. Relevant performance indicators of chicory fermentation products in different treatment groups

[0044] Dry matter (% FM) Crude protein (% DM) Neutral detergent fiber (% DM) pH value Experimental group 1 21.34 17.22 37.25 4.14 Experimental group 2 22.58 18.53 38.69 4.21 Experimental group 3 21.74 17.51 36.93 4.13 Experimental group 4 24.32 19.36 39.32 4.17 Experimental group 5 25.73 19.54 36.14 4.09 Experimental group 6 20.67 17.39 39.62 4.43 Experimental group 7 18.45 16.71 41.35 4.55 Experimental group 8 19.21 16.92 40.20 4.61

[0045] The experimental results showed that adding a certain amount of garlic peel and corn flour during chicory fermentation (experimental groups 1-6) increased the dry matter and crude protein levels, lowered the fermentation pH, and improved the fermentation effect compared to the groups without addition (experimental groups 7-8). The fermentation effect was optimal when the weight ratio of chicory, garlic peel, and corn flour was 50:1:4 (experimental group 5), resulting in the best quality chicory ferment.

[0046] Example 2: Preparation of Sophora japonica extract using the method of the present invention

[0047] The specific operating steps are as follows:

[0048] Take 1 kg of Sophora japonica buds, add 5 L of 70% ethanol for extraction, extract at 85℃ for 2 h, centrifuge, collect the supernatant, filter with a filter membrane to obtain the filtrate, concentrate and freeze dry to obtain Sophora japonica bud extract for later use.

[0049] The rutin content in the Sophora japonica extract prepared in this example was determined to be ≥95%.

[0050] Example 3: Preparation of pine bark extract using the method of the present invention

[0051] The specific operating steps are as follows:

[0052] Take 10 kg of pine bark and add it to 50 L of anhydrous ethanol solution. Then add 0.3 kg of citric acid and extract at 4 °C for 24 h. Concentrate under reduced pressure to obtain a primary concentrate. Analyze the concentrate in water to obtain a chromatographic solution. Concentrate the chromatographic solution under reduced pressure again, condense and centrifuge to obtain the pine extract for later use.

[0053] The proanthocyanidin content of the prepared pine bark extract was determined using the method specified in SW / T1-2015 Pine Bark Extract. The results showed that the proanthocyanidin content in the pine bark extract obtained in this invention was above 95%.

[0054] Example 4: Formulation of the feed additive of the present invention and its functional study

[0055] Chicory ferment, Sophora japonica extract and pine bark extract prepared in Examples 1-3 were mixed and used to prepare feed additives for feeding meat sheep. The proportions of each substance in the additives are shown in Table 3 below.

[0056] Table 3 Formulation table of different feed additives

[0057] Chicory ferment (wt%) Sophora japonica flower extract (wt%) Pine bark extract (wt%) Experimental group 1 70 15 15 Experimental group 2 80 10 10 Experimental group 3 90 5 5 Experimental group 4 80 20 0 Experimental group 5 80 0 20 Experimental group 6 100 0 0 Control group 7 0 0 0

[0058] Thirty-five healthy, disease-free Nanchong black goats, approximately 4 months old and weighing about 35 kg, were randomly divided into 7 groups of 5 goats each. The control group was fed a basal diet, while the experimental groups were fed a mixed diet consisting of 70% basal diet and 30% feed additives. All groups had free access to feed, and the feeding period was 28 days. The basal diet was formulated according to the meat sheep feeding standard (standard number NY / T816-2021), with a concentrate-to-roughage ratio of 5:5. The ingredient composition is shown in Table 4.

[0059] Table 4. Basic Diet Formula for Meat Sheep

[0060] raw material Content wt% Corn silage 30 straw 20 cornmeal 25 soybean meal 8 wheat bran 10 calcium dihydrogen phosphate 1.0 salt 0.5 Compound premix for mutton sheep 5.5 total 100

[0061] Before the experiment began, the breeding site and equipment were disinfected. The sheep were housed in the same shed, but kept in separate pens. They were fed twice daily, at 7:30 AM and 5:30 PM, with free access to feed and water. Immunization and deworming were carried out according to routine procedures, and the sheepfold was cleaned daily.

[0062] (1) On the first and last day of the experiment, the weight of the sheep was measured on an empty stomach before morning feeding. The feed intake of each group of sheep during the experiment was accurately recorded for statistical analysis of average daily weight gain and feed conversion ratio. Average daily weight gain = (final weight - initial weight) / number of days in the experiment; average feed intake = total feed intake of each group / number of days in the experiment × number of sheep; feed conversion ratio = average daily feed intake / average daily weight gain. The growth performance of each group of sheep is shown in Table 5.

[0063] Table 5. Effects of different additives on the growth performance of meat sheep

[0064] Initial weight (kg) Final weight (kg) Average daily weight gain (kg / d) Average daily feed intake (kg / d) Material weight ratio Experimental group 1 35.04 55.21 0.72 1.81 2.51 Experimental group 2 35.11 58.32 0.83 1.84 2.22 Experimental group 3 35.40 56.21 0.74 1.82 2.46 Experimental group 4 35.28 53.73 0.66 1.82 2.76 Experimental group 5 35.73 52.49 0.60 1.80 3 Experimental group 6 35.34 51.36 0.57 1.79 3.14 Control group 7 35.52 50.15 0.52 1.83 3.52

[0065] As can be seen from the results in Table 5, the average daily weight gain of the experimental groups fed with the additives of this application (experimental groups 1-3) was significantly higher than that of the feed additive groups (experimental groups 4-6) without the formula of this invention and the group without the additives (experimental group 7). The experimental groups fed with the additives of this application significantly reduced the feed conversion ratio. Compared with the group without the additives, the feed conversion ratio was reduced by 58% under the optimal conditions of this application. It can be seen that the additives of this invention significantly improve the growth performance of meat sheep.

[0066] (2) After the sheep were fed for 28 days, they were slaughtered and the meat quality-related indicators of the sheep were measured, including cooking loss, backfat thickness, eye muscle area, shear force and longissimus dorsi muscle nutritional components.

[0067] The method for determining cooking loss is as follows: After slaughter, the meat sample is left to stand for 24 hours to remove acid. A piece of meat weighing about 30g is weighed and recorded as m1. The meat sample is sealed in a plastic bag, placed in a constant temperature water bath at 85℃ and heated for 40 minutes. After cooling, the water is squeezed out and the weight is recorded as m2. Cooking loss (%) = 100 × (m1 - m2) / m1.

[0068] The method for measuring back fat thickness is as follows: use vernier calipers to measure the back fat thickness at three points: the posterior edge of the scapula, the chest and waist, and the buttocks, and take the average value.

[0069] The method for measuring the area of ​​the eye muscles is as follows: a flat cross-section of the longissimus dorsi muscle is cut at the 12th to 13th intercostal space, the longest diameter and the widest diameter of the cross-section are measured, and the area of ​​the eye muscles is calculated according to the method for calculating the area of ​​an ellipse.

[0070] The method for determining muscle shear force is as described in NY / T1180-2006.

[0071] The results of the above meat quality indicators are shown in Table 6 below.

[0072] Table 6. Effects of different feed additives on mutton meat quality

[0073] Cooking loss % Back fat thickness (cm) <![CDATA[Ocular muscle area cm 2 > Shear force N Experimental group 1 32.12 3.05 21.82 31.7 Experimental group 2 31.89 3.04 21.43 30.2 Experimental group 3 32.26 3.10 21.67 32.5 Experimental group 4 33.54 3.28 20.95 35.8 Experimental group 5 33.67 3.21 21.38 37.4 Experimental group 6 34.28 3.34 21.84 38.9 Control group 7 35.13 3.68 21.15 41.3

[0074] As shown in Table 6, the group fed with the additive of the present invention had lower cooking loss, lower backfat thickness, comparable eye muscle area, and significantly reduced shear force of the longissimus dorsi muscle, indicating that the additive of the present invention can significantly improve the muscle quality of mutton sheep.

[0075] (3) The longissimus dorsi muscle was collected, and its moisture, crude protein, crude fat, and crude ash were determined. Moisture was determined by oven drying, crude protein by Kjeldahl nitrogen determination, crude fat by Soxhlet extraction, and crude ash by high-temperature ignition. The nutritional composition of the longissimus dorsi muscle is shown in Table 7 below.

[0076] Table 7. Effects of different feed additives on muscle nutrient composition

[0077] Moisture (wt%) Crude protein wt% Crude fat wt% Coarse ash content (wt%) Experimental group 1 71.25 21.51 4.59 0.99 Experimental group 2 71.33 21.35 4.62 0.96 Experimental group 3 71.69 21.56 4.43 0.94 Experimental group 4 71.27 22.21 4.10 1.01 Experimental group 5 71.93 22.10 4.18 1.02 Experimental group 6 72.01 22.59 3.85 1.04 Control group 7 71.56 22.47 3.59 0.98

[0078] As shown in Table 7, feeding the additive of the present invention reduced the protein content in the longissimus dorsi muscle and increased its fat content, while the contents of moisture, ash and other impurities were comparable. Therefore, it effectively improved the tenderness and flavor of the meat and improved the quality of the mutton.

[0079] In summary, this invention provides an additive suitable for improving the growth performance and meat quality of sheep. When this additive replaces 30% of the basal diet, it can significantly improve the growth performance of sheep and improve the meat quality.

Claims

1. A feed additive for improving the growth performance and meat quality of mutton sheep, characterized in that, Its composition includes, by weight percentage: 70-90% chicory ferment, 5-15% sophora japonica extract, and 5-15% pine bark extract.

2. The feed additive for improving the growth performance and meat quality of sheep according to claim 1, characterized in that, Its composition is as follows: by weight percentage, 80% chicory ferment, 10% sophora japonica extract, and 10% pine bark extract.

3. The feed additive for improving the growth performance and meat quality of sheep according to claim 1 or 2, characterized in that: The chicory ferment is prepared by fermenting chicory, garlic peel, and corn flour.

4. The feed additive for improving the growth performance and meat quality of sheep according to claim 3, characterized in that: The weight ratio of chicory, garlic peel, and corn flour is 20-30:0.1-1:1-3.

5. The feed additive for improving the growth performance and meat quality of sheep according to claim 4, characterized in that: The weight ratio of chicory, garlic peel, and corn flour is 50:1:

4.

6. The feed additive for improving the growth performance and meat quality of sheep according to claim 3, characterized in that, The preparation method of the chicory ferment is as follows: weigh chicory, garlic peel and corn flour by weight, chop the chicory into 3-5cm, add garlic peel and corn flour, mix evenly, add 1-10% of the fermenting agent by weight of the substrate, seal, and ferment in the dark at 25-30℃ for 3-10 days to obtain the chicory ferment.

7. The feed additive for improving the growth performance and meat quality of sheep according to claim 6, characterized in that: The fermentation agent is a mixture of Lactobacillus plantarum, Bacillus subtilis, and Aspergillus niger.

8. The feed additive for improving the growth performance and meat quality of sheep according to claim 7, characterized in that: The ratio of viable counts of *Lactobacillus plantarum*, *Bacillus subtilis*, and *Aspergillus niger* is 6:1–3:2–6.

9. The feed additive for improving the growth performance and meat quality of sheep according to claim 1 or 2, characterized in that, The preparation method of the Sophora japonica extract is as follows: Sophora japonica flowers are crushed and sieved, added to a 70-75% ethanol solution, and extracted at 80-90℃ for 1.5-3 hours. The extract is centrifuged, the supernatant is collected, filtered through a filter membrane, the filtrate is concentrated and then freeze-dried to prepare the Sophora japonica extract.

10. The feed additive for improving the growth performance and meat quality of sheep according to claim 1 or 2, characterized in that, The method for preparing the pine bark extract is as follows: Pine bark is crushed and added to a 70-75% ethanol solution, followed by 2-3% citric acid by weight of the pine bark. The mixture is then extracted at 4-6°C for 24-48 hours. The extract is concentrated under reduced pressure to obtain a primary concentrate. The concentrate is then chromatographically analyzed in water to obtain a chromatographic solution. This chromatographic solution is then concentrated under reduced pressure again, condensed, and centrifuged to obtain the pine bark extract.