A kind of meat sheep feed additive containing spirea japonica and its application

Abstract

The application discloses a kind of containing prunella vulgaris mutton feed additive and its application, belong to the field of animal nutrition and feed science.The feed additive includes prunella vulgaris, and the addition amount in mutton basic daily ration is 0.5 wt %~1.5 wt %, preferably 0.8 wt %~1.2 wt %, most preferably 1.0 wt %, and the feeding period is not less than 60 days.Under the addition amount of 1.0 wt %, the feed conversion ratio can be significantly reduced, the back long muscle shear force is reduced, the serum immunoglobulin and complement concentration are improved, the muscle total amino acid, glutamic acid, linoleic acid, arachidonic acid and other flavor substance content are increased, and the abundance of Rikenellaceae_RC9_gut_group and Christensenellaceae_R‑7_group and other bacteria genera in rumen is significantly regulated.The application realizes the multidimensional synergistic improvement of growth performance, immune function, meat quality and flavor, and is suitable for mutton large-scale breeding.

Description

Technical Field

[0001] This invention relates to the fields of animal nutrition and feed science and natural plant additives, specifically to a meat sheep feed additive containing Prunella vulgaris, and its application in improving the growth performance of meat sheep, enhancing immune function, improving meat quality and flavor, and regulating the rumen microbial community. Background Technology

[0002] 1. Technological requirements of the mutton sheep farming industry With the upgrading of Chinese residents' consumption structure and the popularization of healthy eating concepts, the demand for mutton continues to grow, placing higher demands on mutton quality (tenderness, flavor, and color) and the safety of the breeding process. Meanwhile, the country continues to promote the "antibiotic reduction and antibiotic replacement" strategy, and natural plant additives, due to their advantages such as being green, safe, and residue-free, have become a research hotspot in the field of animal nutrition. However, the application of existing plant additives in sheep meat still faces the following technical bottlenecks: unclear mechanisms of action, unknown dose-effects, missing safety boundaries, and insufficient multi-dimensional synergistic improvement capabilities.

[0003] 2. Known applications and limitations of Prunella vulgaris Prunella vulgaris, a perennial herb of the Lamiaceae family, is a medicinal and edible resource widely used in the pharmaceutical and food industries. Current research indicates that Prunella vulgaris is rich in triterpenoids, flavonoids, polysaccharides, and other active ingredients, possessing antibacterial, anti-inflammatory, and antioxidant activities. In livestock farming, studies have shown its use in feed for monogastric animals such as chickens and pigs to promote growth and disease resistance.

[0004] However, research on the application of Prunella vulgaris in ruminants (especially meat sheep) is extremely limited, and existing technologies have the following obvious shortcomings: (1) Lack of appropriate dosage range and safety boundary Existing literature only reports the extensive addition of Prunella vulgaris to monogastric animals, without conducting dose-effect studies on the systemic physiological characteristics of meat sheep (such as rumen digestion and immune regulation), and without clarifying the optimal addition dose, effective dose window and safety upper limit of Prunella vulgaris in meat sheep. This results in a lack of scientific basis for practical application, and there is a risk of blind addition, unstable effects and even safety risks.

[0005] (2) There is a gap in our understanding of its regulatory role in immune function. Currently, no research has revealed the effects of Prunella vulgaris on the immune function of ruminants. Whether it exhibits dose-dependent effects or nonlinear effects (such as enhancement at low doses and inhibition at high doses) is completely unknown, which directly restricts its safe application as an immunomodulatory additive.

[0006] (3) The rumen microbial regulatory mechanism has not been revealed. The nutritional metabolism and immune function of ruminants are highly dependent on the rumen microbiome. Current technologies lack any mechanistic research on how *Prunella vulgaris* affects host growth, immunity, and meat formation by regulating specific rumen microbiota, thus failing to establish a complete technological chain of "additive-microbiota-host."

[0007] (4) Lack of systematic data for multi-dimensional collaborative improvement Existing research on plant additives mostly focuses on single indicators (such as growth performance or meat quality), lacking a systematic evaluation that simultaneously covers "growth performance, immune function, meat quality, flavor substances, and microbial mechanisms," making it difficult to meet the comprehensive needs of modern aquaculture for "high efficiency, safety, high quality, and flavor."

[0008] 3. Summary of Existing Technologies In summary, there is currently no systematic research on the appropriate dosage, immune regulation mechanism, rumen microbiota mechanism, and multi-dimensional synergistic effects of Prunella vulgaris in meat sheep. There is an urgent need to develop a Prunella vulgaris feed additive with a clear dosage, well-defined mechanism, stable effect, and controllable safety, as well as its application method. Summary of the Invention

[0009] (a) Purpose of the invention This invention aims to overcome the shortcomings of existing technologies and provide a mutton sheep feed additive containing Prunella vulgaris and its application. Specifically, the technical problems to be solved by this invention are: to clarify the appropriate dosage and safety boundaries of Prunella vulgaris in mutton sheep feed, to reveal its bidirectional regulatory mechanism on the immune function of mutton sheep, to elucidate its mechanism of action in improving meat quality and flavor by regulating specific rumen flora, and to achieve multi-dimensional synergistic improvement of growth performance, immune function, meat quality, and flavor substances, thus providing a scientific, safe, and efficient natural plant additive solution for green and healthy mutton sheep farming.

[0010] (II) Technical Solution To achieve the above-mentioned objectives, the present invention provides the following technical solution: 1. A feed additive for mutton sheep containing Prunella vulgaris, wherein the feed additive contains Prunella vulgaris and the amount of Prunella vulgaris added to the basal diet of mutton sheep is 0.5% to 1.5% (by weight).

[0011] Furthermore, the amount of Prunella vulgaris added is 0.8% to 1.2% (by mass), preferably 1.0% (by mass); the Prunella vulgaris is the dried powder of the whole herb.

[0012] Furthermore, the basal diet is a basal diet for meat sheep, and its composition by mass percentage includes: corn 45.0%, soybean meal 12.0%, wheat bran 8.0%, alfalfa hay 20.0%, sheep grass 12.0%, dicalcium phosphate 1.0%, limestone powder 1.0%, salt 0.5%, and premix 0.5%.

[0013] 2. Application of the aforementioned feed additives in simultaneously improving the growth performance of meat sheep, enhancing immune function, improving meat quality, and regulating the rumen microbial community: The feeding period for meat sheep using the aforementioned feed additives shall not be less than 60 days.

[0014] Preferably, the amount of Prunella vulgaris added is 0.8% to 1.2%, more preferably 1.0%.

[0015] Furthermore, the improvement in growth performance is manifested in reducing the feed conversion ratio; the enhancement of immune function is manifested in increasing the concentration of serum immunoglobulin A, immunoglobulin G, immunoglobulin M, complement C3 and / or complement C4.

[0016] Furthermore, the improvement in meat quality includes at least one of the following: reducing the shear force of the longissimus dorsi muscle; reducing the yellowness value of the meat color; and increasing the crude protein content of the muscle.

[0017] Furthermore, the regulation of the rumen microbiome includes increasing the relative abundance of Rikenellaceae_RC9_gut_group and / or Christensenellaceae_R-7_group in the rumen.

[0018] Furthermore, the improvement of meat quality also includes increasing the content of total amino acids, glutamic acid, aspartic acid, threonine, serine, linoleic acid, arachidonic acid and / or arachidonic acid in the muscle.

[0019] Furthermore, the mutton sheep are selected from at least one of the following: Zhongyu mutton sheep, Small-tailed Han sheep, Dorper sheep, Suffolk sheep, and their hybrid offspring.

[0020] (III) Beneficial Effects Compared with the prior art, the present invention has the following outstanding beneficial effects and technological advancements: 1. For the first time, the optimal dosage window and safety margin of Prunella vulgaris in mutton sheep were clearly defined. This invention, through a systematic dose-effect study, reveals for the first time that Prunella vulgaris exhibits a bidirectional regulatory effect on the immune function of sheep, characterized by "enhancement at low doses and inhibition at high doses." Specifically: When the addition amount was 0.5% to 1.0%, the concentrations of serum immunoglobulins (IgA, IgG, IgM) and complement (C3, C4) were significantly increased (P < 0.001), indicating that this dosage range had a significant immune-enhancing effect. When the addition amount reached 1.5%, the above-mentioned immune indicators decreased significantly (P<0.001), showing an immunosuppressive effect.

[0021] This discovery breaks through the traditional technical bias in the field that "the higher the dosage of Chinese herbal medicine additives, the better the effect," and provides a clear dosage window (0.5% to 1.2%) and a safety upper limit (≤1.2%) for the safe application of Prunella vulgaris, avoiding the immune safety risks caused by blindly adding high doses.

[0022] 2. Achieve synergistic improvement across multiple dimensions: growth, immunity, quality, and flavor. At an addition amount of 1.0%, this invention simultaneously achieves the following synergistic and beneficial effects:

[0023] The above results demonstrate that the present invention achieves synergistic optimization of growth performance, immune function, meat quality and flavor of mutton sheep, rather than improvement of a single indicator, reflecting significant technological integration and innovation.

[0024] 3. The mechanism by which Prunella vulgaris regulates specific rumen flora is revealed for the first time. This invention, using 16S rRNA high-throughput sequencing technology, is the first to discover that Prunella vulgaris can significantly regulate the relative abundance of key functional bacterial genera in the rumen of meat sheep: The relative abundance of Rikenellaceae_RC9_gut_group and Christensenellaceae_R-7_group showed a significant change, first decreasing and then increasing with the addition level of Prunella vulgaris (P < 0.05). The changes in the abundance of the aforementioned bacterial genera are synchronous with the changes in the content of key flavor compounds (glutamic acid, linoleic acid, and arachidonic acid) in the muscle.

[0025] This discovery establishes for the first time a complete mechanism chain of action of "Prunella vulgaris additive → rumen-specific microbial regulation → muscle flavor enhancement", providing a new theoretical basis and technical path for plant additives to improve the quality of livestock products by regulating intestinal microorganisms.

[0026] 4. The application has clear security and high industrialization value. This invention clarifies that the safe upper limit for adding Prunella vulgaris to mutton sheep is 1.2%. While exceeding this dose (1.5%) can improve some growth performance, it will produce an immunosuppressive effect. Establishing this safe dose boundary provides a dosage control standard for the large-scale application of Prunella vulgaris in mutton sheep farming, effectively avoiding potential safety risks.

[0027] Meanwhile, as a plant that is both a medicine and food, Prunella vulgaris has a wide range of sources, controllable costs, and simple processing (only drying and pulverizing are required), and has good prospects for industrial application and economic benefits. Attached Figure Description

[0028] Figure 1 Bar chart showing the effect of different amounts of Prunella vulgaris added on serum immunoglobulins (IgG, IgA, IgM) in mutton sheep; Figure 2 Bar chart showing the effect of different amounts of Prunella vulgaris added on the shear force of the longissimus dorsi muscle in mutton sheep; Figure 3 Bar chart showing the effect of different amounts of Prunella vulgaris added on the relative abundance of rumen-differentiated bacterial genera; Figure 4 Bar chart showing the effect of different amounts of Prunella vulgaris added on the content of key flavor compounds in muscle. Figure 5 Principal component analysis diagram of the longest muscle in the back of the electronic nose. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] Example 1: Preparation of Prunella vulgaris additive Take the dried whole herb of Prunella vulgaris, remove impurities, dry it in an oven at 60℃ until constant weight, pulverize it with a pulverizer, and pass it through a 60-mesh sieve to obtain the Prunella vulgaris powder additive. Store in a sealed container for later use.

[0031] Example 2: Formulation and Feeding Experiment Design of Feed Containing Prunella vulgaris 2.1 Basic Diet Formulation The basal diet was designed according to the "Nutritional Requirements for Mutton Sheep" (NY / T 816-2021), and its composition and nutritional levels are shown in Table 1. The basal diet was prepared by mixing the ingredients according to the formula in Table 1.

[0032] Table 1. Composition and nutritional levels of the basal diet (air-dried basal diet)

[0033] ¹ The premix provides the following per kilogram of feed: 50 mg iron (Fe), 10 mg copper (Cu), 40 mg zinc (Zn), 30 mg manganese (Mn), 0.5 mg iodine (I), 0.2 mg selenium (Se), 0.1 mg cobalt (Co), 5000 IU vitamin A, 1000 IU vitamin D, and 50 IU vitamin E.

[0034] ² All nutritional levels are calculated values.

[0035] Different weight percentages of Prunella vulgaris powder (0%, 0.5%, 1.0%, and 1.5%) were added to the basal diet and mixed thoroughly to prepare the control group diet (0%), experimental group I diet (0.5%), experimental group II diet (1.0%), and experimental group III diet (1.5%).

[0036] 2.2 Experimental Animals and Grouping Sixty healthy male lambs aged 3-5 months from the Henan-style mutton sheep population, with similar body weight (31±4.64 kg), were randomly divided into 4 groups of 15 lambs each. There were no significant differences in initial body weight among the groups (P>0.05). Grouping and treatment were as follows: a. Control group: fed a basal diet (with 0% addition of Prunella vulgaris); b. Experimental Group I: fed a basal diet plus 0.5% Prunella vulgaris; c. Experimental Group II: fed a basal diet plus 1.0% Prunella vulgaris; d. Experimental Group III: Feeded with a basal diet plus 1.5% Prunella vulgaris.

[0037] 2.3 Feeding and Management The experiment was conducted at Henan Musheng Agricultural Technology Co., Ltd. from July to October 2025. Prior to the experiment, the sheepfold was disinfected and the feed troughs were cleaned. During the experiment, the sheep were fed twice daily, at 06:00 and 18:00, with free access to feed and water. The pre-experiment period was 10 days, and the formal trial period was 60 days. The experiment complied with animal welfare requirements and was approved by the Animal Ethics Committee of Henan University of Animal Husbandry and Economics (ethics approval number: HUAHE-2021-397).

[0038] 2.4 Sample Collection and Index Measurement Methods 2.4.1 Growth performance determination Weigh the animals on an empty stomach on the morning of the first and last day of the trial period, record their weight, and calculate the average daily gain (ADG). Record the amount of feed fed per repeat and the amount of feed left over during the trial period, and calculate the average daily feed intake (ADFI) and feed conversion ratio (F / G).

[0039] 2.4.2 Slaughter performance and organ index determination After the trial period, five sheep were randomly selected from each group, fasted for 24 hours and deprived of water for 2 hours, then weighed and slaughtered. Pre-slaughter live weight, carcass weight, dressing percentage, GR value, backfat thickness, and eye muscle area were measured. The heart, liver, spleen, and lungs were separated, weighed, and organ indices were calculated.

[0040] 2.4.3 Meat quality determination Samples of the longissimus dorsi muscle were taken and the following were measured: pH value (45 min and 24 h after slaughter), cooked meat percentage, drip loss, shear force (using a texture analyzer), meat color (brightness L*, redness a*, yellowness b*, using a colorimeter), and textural properties (TPA).

[0041] 2.4.4 Determination of muscle nutrient composition The water, crude protein, and crude fat content in muscle were determined according to the methods in GB 5009.3-2016, GB 5009.5-2025, and GB 5009.6-2016.

[0042] 2.4.5 Blood index measurement On day 60 of the trial period, venous blood was collected and serum was separated. Serum biochemical indicators were detected using a fully automated biochemical analyzer; serum immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), complement C3, and complement C4 concentrations were determined using a one-step sandwich enzyme-linked immunosorbent assay (ELISA) with double antibodies.

[0043] 2.4.6 Analysis of rumen microbial diversity On day 60 of the trial period, rumen fluid was collected using a rumen sampler, and the microbial community was determined using next-generation high-throughput sequencing technology (completed by Shanghai Meiji Biopharmaceutical Technology Co., Ltd.).

[0044] 2.4.7 Determination of flavor compounds in muscle The amino acid and fatty acid content in muscle was determined according to the methods in GB 5009.168-2016 and GB 5009.124-2016.

[0045] 2.4.8 Electronic nose analysis Samples were taken from the longissimus dorsi muscle, subcutaneous fat, and tail fat. Odor was measured using an electronic nose, and flavor differences were assessed by principal component analysis (PCA).

[0046] 2.5 Data Statistics and Analysis Data were processed using Excel, and one-way ANOVA was performed using SPSS 26.0. Multiple comparisons were conducted using the LSD method. P < 0.05 was considered statistically significant, and P < 0.01 was considered highly statistically significant. Results are expressed as mean ± standard deviation.

[0047] Example 3: Effects of different doses of Prunella vulgaris on growth performance and conventional meat quality of sheep Feeding trials were conducted according to the method in Example 2, and growth performance, slaughter performance, organ index, meat quality, and muscle nutrient composition of each group were measured.

[0048] 3.1 Growth performance The growth performance results for each group are shown in Table 2.

[0049] Table 2. Effects of different doses of Prunella vulgaris on the growth performance of sheep in the Central and Southern Henan regions.

[0050] Note: Different uppercase letters in the superscript of the same data indicate extremely significant differences (P < 0.01), different lowercase letters indicate significant differences (P < 0.05), and no letter indicates no significant difference (P > 0.05). The same applies to the following table.

[0051] As shown in Table 2, compared with the control group, the feed conversion ratio of experimental group III was significantly lower (P < 0.01), indicating that adding 1.5% Prunella vulgaris can significantly improve feed conversion efficiency. The average daily weight gain of each experimental group increased to varying degrees, but none reached a significant level.

[0052] 3.2 Slaughter performance The slaughter performance results for each group are shown in Table 3. There were no significant differences among the groups in terms of pre-slaughter live weight, carcass weight, dressing percentage, GR value, backfat thickness, and eye muscle area (P>0.05), indicating that the Prunella vulgaris additive had no adverse effect on the slaughter performance of mutton sheep.

[0053] Table 3. Effects of different doses of Prunella vulgaris on the slaughter performance of sheep in the Central and Southern Henan regions.

[0054] 3.3 Organ Index The results of organ indices for each group are shown in Table 4. The spleen index in Experiment II was significantly increased (P<0.05), suggesting that 1.0% Prunella vulgaris may enhance the function of immune organs.

[0055] Table 4. Effects of different doses of Prunella vulgaris on organ index of sheep in Central and Southern Henan Province

[0056] 3.4 Meat quality The meat quality test results for each group are shown in Table 5.

[0057] Table 5. Effects of different doses of Prunella vulgaris on the quality of mutton from Henan Province.

[0058] As shown in Table 5: The shear force of the longissimus dorsi muscle was significantly reduced in both experimental groups II and III (P < 0.01, see details). Figure 2 (Bar chart showing the effect of different amounts of Prunella vulgaris added on the shear force of the longissimus dorsi muscle of mutton sheep) indicates that Prunella vulgaris can significantly improve muscle tenderness; The yellowness value (b*) of the flesh color in Experiment II was significantly reduced (P<0.05), suggesting that 1.0% Prunella vulgaris can improve flesh color stability; The chewing ability of group III was significantly improved (P<0.01), which may be related to the increase in intramuscular fat content.

[0059] 3.5 Muscle Nutritional Components The results of muscle nutritional composition in each group are shown in Table 6. The crude protein content in group II was significantly increased (P<0.05), and the crude fat content in group III was extremely significantly increased (P<0.01), indicating that Prunella vulgaris can improve the nutritional quality of muscle.

[0060] Table 6. Effects of different doses of Prunella vulgaris on the nutritional components of muscle in sheep from the Central and Southern Henan regions.

[0061] Example 4: Effects of different doses of Prunella vulgaris on the immune function of sheep Serum was collected according to the method in Example 2, and the concentrations of immune factors in each group were measured. The results are shown in Table 7.

[0062] Table 7. Effects of different doses of Prunella vulgaris on serum immune factors in sheep from Henan and Hebei provinces.

[0063] As shown in Table 7, compared with the control group: The concentrations of IgG, IgA, IgM, C3, and C4 in experimental groups I and II were all significantly increased (P < 0.001), indicating that 0.5%–1.0% Prunella vulgaris had a significant immunomodulatory effect; the above indicators in experimental group III were significantly decreased (P < 0.001), showing an immunosuppressive effect. For details on the trends of serum immunoglobulin (IgG, IgA, IgM) changes, please refer to [link to relevant documentation]. Figure 1 (Bar chart showing the effect of different amounts of Prunella vulgaris added on serum immunoglobulins in mutton sheep).

[0064] The above results indicate that Prunella vulgaris has a dose-dependent bidirectional regulatory effect on the immune function of sheep: low dose (0.5%–1.0%) enhances immunity, while high dose (1.5%) inhibits immunity.

[0065] Example 5: Analysis of rumen microbial diversity and muscle flavor compounds 5.1 Rumen Microbial Diversity Rumen fluid was collected and 16S rRNA high-throughput sequencing was performed according to the method in Example 2. The results of rumen microbial diversity analysis for each group are as follows: The total number of OTUs detected in rumen fluid samples from each group was as follows: 1133 in the control group, 753 in group I, 1111 in group II, and 1251 in group III. There were no significant differences in the Alpha diversity indices (Ace, Chao, Shannon, Simpson) among the groups (P > 0.05), indicating that *Prunella vulgaris* did not significantly alter the richness and diversity of the gut microbiota.

[0066] At the phylum level, Firmicutes, Bacteroidetes, and Pseudomonas were the dominant phyla, accounting for more than 93.18% of the total relative abundance.

[0067] At the genus level, a total of 12 differentially abundant genera were enriched. Among them, the relative abundance of Rikenellaceae_RC9_gut_group, Christensenellaceae_R-7_group, and norank_f_F082 showed a significant change, first decreasing and then increasing with the addition level of Prunella vulgaris (P < 0.05). See details... Figure 3 (Bar chart showing the effect of different amounts of Prunella vulgaris added on the relative abundance of rumen-differentiated bacterial genera).

[0068] 5.2 Amino acid composition of muscle The results of the amino acid content determination of each group of muscles are shown in Table 8.

[0069] Table 8. Effects of different doses of Prunella vulgaris on amino acid content in the muscle of sheep from Henan Province.

[0070] As shown in Table 8, the contents of total amino acids, aspartic acid, threonine, serine, glutamic acid, isoleucine, leucine, tyrosine, and arginine in Experiment II were all significantly or substantially increased (P < 0.01 or P < 0.05). Among them, the contents of glutamic acid (umami amino acid) and aspartic acid (umami amino acid) were significantly increased, indicating that 1.0% Prunella vulgaris can effectively improve the umami flavor of the muscle.

[0071] 5.3 Composition of muscle fatty acids The results of the determination of fatty acid content in the muscles of each group are shown in Table 9.

[0072] Table 9. Effects of different doses of Prunella vulgaris on fatty acid content in the muscle of mutton sheep from Henan Province.

[0073] Table 9 shows that the contents of linoleic acid (C18:2n6c), arachidonic acid (C20:2), arachidonic acid (C20:4n6), icosanoic acid (C21:0), and lignotaric acid (C24:0) were all significantly increased in group II (P < 0.01); while the content of oleic acid (C18:1n9c) was significantly increased in group III (P < 0.05). Unsaturated fatty acids are important precursors of flavor compounds, and their increased content helps improve the flavor of mutton. For details on the content trends of the above key flavor compounds (amino acids and unsaturated fatty acids), please refer to [link to table]. Figure 4 (Bar chart showing the effect of different amounts of Prunella vulgaris added on the content of key flavor compounds in muscle).

[0074] 5.4 Electronic Nose Analysis Electronic nose analysis was performed on raw and cooked longissimus dorsi muscle, subcutaneous fat, and tail fat. Principal component analysis (PCA) results showed that the flavor differentiation of cooked meat was greater than that of raw meat in each group. Experimental group II (1.0% additive) had the largest distance from the control group in the principal component space of cooked meat flavor, indicating the most significant change in flavor characteristics. (See details...) Figure 5 (Principal component analysis diagram of the longest muscle in the electronic nose).

[0075] Example 6: Comprehensive Effect Evaluation and Optimal Dosage Screening Based on the results of Examples 3-5, the overall effects of different doses of Prunella vulgaris were evaluated, and the results are summarized in Table 10.

[0076] Table 10. Evaluation of the comprehensive effects of different doses of Prunella vulgaris on meat sheep in Henan Province.

[0077] As shown in Table 10, the 1.0% addition amount has the best overall performance in terms of immune function, meat quality and flavor substance improvement, and there is no risk of immunosuppression. It is the optimal dosage of the present invention.

[0078] Furthermore, following the method of Example 2, the dosage of Prunella vulgaris was set to 0.8%, 1.0%, and 1.2%, respectively, and a feeding experiment was conducted on Zhongyu mutton sheep. The results showed: Within the range of 0.8% to 1.2%, all dosage groups significantly increased serum immunoglobulin levels (P < 0.01), improved muscle tenderness (P < 0.05), and increased the content of flavor substances such as glutamic acid and linoleic acid in the muscle (P < 0.05); no immunosuppression was observed in any dosage group.

[0079] Therefore, the preferred dosage range of Prunella vulgaris in this invention is 0.8% to 1.2%, with 1.0% being the most preferred dosage.

[0080] Example 7: Validation of the application of the preferred dosage in other meat sheep breeds Following the method in Example 2, Dorper sheep, Small-tailed Han sheep, and Suffolk sheep were used as experimental subjects. 1.0% Prunella vulgaris was added to their basal diet for 60 days. The results showed that: The feed conversion ratio of all breeds of meat sheep decreased, while the immunoglobulin level increased significantly (P<0.05). The shear force of the longissimus dorsi muscle decreased, and the content of glutamate and linoleic acid in the muscle increased significantly (P<0.05).

[0081] This demonstrates that the technical solution of the present invention is applicable to a variety of meat sheep breeds.

[0082] Summary of Implementation Examples As can be seen from Examples 1-7 above, the present invention provides a feed additive for mutton sheep containing Prunella vulgaris and its application method. Compared with the prior art, the present invention has the following outstanding features: 1. Dosage is clearly defined: The appropriate addition amount of Prunella vulgaris to the basal diet is 0.8% to 1.2%, with the optimal value being 1.0%.

[0083] 2. Bidirectional immune regulation: For the first time, it was revealed that Prunella vulgaris has a bidirectional regulatory effect on the immune function of sheep, which is "enhanced by low dose and inhibited by high dose", and a safe dose window was established.

[0084] 3. Multi-dimensional synergistic improvement: At a dosage of 1.0%, it can simultaneously improve growth performance, enhance immune function, and improve meat quality and flavor compounds, achieving synergistic effects.

[0085] 4. Clear mechanism: It affects the metabolism of muscle flavor substances by regulating the abundance of key bacterial genera such as Rikenellaceae_RC9_gut_group and Christensenellaceae_R-7_group in the rumen.

[0086] 5. Safe and controllable: The upper limit for safe addition (≤1.2%) has been clearly defined, avoiding the risk of immunosuppression caused by high doses.

[0087] The technical solution of this invention is simple to operate, cost-controllable, and has stable effects. It is suitable for large-scale sheep farming and has good prospects for industrial application.

[0088] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope of the present invention.

Claims

1. A feed additive for mutton sheep containing Prunella vulgaris, characterized in that: The feed additive contains Prunella vulgaris, and the amount of Prunella vulgaris added to the basal diet of meat sheep is 0.5 wt% to 1.5 wt%.

2. The feed additive according to claim 1, characterized in that: The amount of Prunella vulgaris added is 0.8 wt% to 1.2 wt%; the Prunella vulgaris is the dried powder of the whole herb.

3. The feed additive according to claim 2, characterized in that: The amount of Prunella vulgaris added was 1.0 wt%.

4. The application of the feed additive according to any one of claims 1 to 3 in simultaneously improving the growth performance of meat sheep, enhancing immune function, improving meat quality, and regulating the rumen microbial community, characterized in that: The feeding cycle for the feed additive shall be no less than 60 days.

5. The application according to claim 4, characterized in that: The improvement in growth performance of mutton sheep is manifested by reducing the feed conversion ratio; the enhancement of immune function is manifested by increasing the concentration of serum immunoglobulin A, immunoglobulin G, immunoglobulin M, complement C3 and / or complement C4.

6. The application according to claim 4, characterized in that: The improvement of meat quality includes at least one of the following: reducing the shear force of the longissimus dorsi muscle; reducing the yellowness value of meat color; and increasing the crude protein content of muscle.

7. The application according to claim 4, characterized in that: The regulation of the rumen microbiome includes increasing the relative abundance of Rikenellaceae_RC9_gut_group and / or Christensenellaceae_R-7_group in the rumen.

8. The application according to claim 4, characterized in that: The improvement of meat quality also includes increasing the content of total amino acids, glutamic acid, aspartic acid, threonine, serine, linoleic acid, arachidonic acid and / or arachidonic acid in the muscle.

9. The application according to claim 4, characterized in that: The mutton sheep are selected from at least one of the following: Central Henan mutton sheep, Small-tailed Han sheep, Dorper sheep, Suffolk sheep, and their hybrid offspring.

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