A method for improving intestinal immunity in sika deer by feeding hydrolyzed tannins

Abstract

This invention provides a method for improving the intestinal immunity of sika deer by feeding them hydrolyzed tannins. The method involves adding 0.8% food-grade hydrolyzed tannins to the sika deer's daily diet, uniformly mixing the hydrolyzed tannins into the concentrate feed, and feeding this mixture continuously for one month, avoiding the sika deer's calving period. Studies have shown that this dosage significantly improves the diversity and richness of the sika deer's intestinal flora, optimizes the intestinal flora structure, and significantly increases the levels of IgA and IgG in feces, thereby enhancing the intestinal mucosal immune function. Compared to a higher dosage of 2%, the 0.8% dosage does not inhibit beneficial intestinal bacteria, is highly safe, simple to operate, and easy to promote and apply in farms.

Description

Technical Field

[0001] This invention belongs to the field of animal nutrition and feed science and technology, specifically relating to a feeding method for adding hydrolyzed tannins to the diet to improve the intestinal immunity of sika deer. Background Technology

[0002] Sika deer (Cervus nippon) are an important special economic animal in my country, and their antlers, venison, and blood products have extremely high medicinal and economic value. With the continuous expansion of sika deer farming, improving the health and profitability of sika deer has become a focus of industry attention. The intestine is the largest immune organ in an animal, and the balance of the intestinal flora directly affects the animal's digestive and absorptive capacity, immune function, and overall health. Recent studies have shown that intestinal flora imbalance is closely related to the occurrence of various diseases, including intestinal inflammation and decreased immune function. Therefore, improving the intestinal microecological environment of sika deer and enhancing their intestinal immunity through nutritional regulation is of great significance for promoting healthy sika deer farming.

[0003] Tannins are a class of polyphenolic compounds widely found in plants, possessing various biological activities such as antioxidant, antibacterial, and anti-inflammatory properties. Based on their chemical structure, tannins can be divided into two main categories: hydrolyzable tannins and condensed tannins. The application of hydrolyzable tannins in animal nutrition has gradually attracted attention, as they can regulate intestinal flora structure, inhibit the growth of pathogenic bacteria, and enhance intestinal barrier function, thereby improving animal gut health.

[0004] However, current research on the application of tannins in sika deer farming is limited, especially regarding the effects of hydrolyzed tannins on the gut microbiota and intestinal immunity of sika deer, which lacks systematic study. In existing technologies, the dosage and feeding method of tannin addition are not clearly defined; excessively high tannin levels may inhibit beneficial gut bacteria, thereby harming intestinal health. Therefore, there is an urgent need to develop a safe and effective tannin feeding method to achieve precise regulation of intestinal immunity in sika deer. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for improving the intestinal immunity of sika deer by feeding hydrolyzed tannins, which effectively improves the intestinal flora structure and increases the level of intestinal immunoglobulins in sika deer by optimizing the dosage and timing of hydrolyzed tannins. This enhances the intestinal immunity and overall health of sika deer.

[0006] To solve the above-mentioned technical problems, the technical solution adopted in this invention is: a method for improving the intestinal immunity of sika deer by feeding hydrolyzed tannins. The method involves adding 0.8% food-grade hydrolyzed tannins to the daily diet of sika deer, uniformly mixing the hydrolyzed tannins into the concentrated feed, and feeding continuously for one month. Feeding should be avoided during the sika deer's parturition period to prevent adverse effects on pregnant and lactating does and fawns.

[0007] Compared with the prior art, the present invention has the following significant technical effects: Tannins can bind with proteins in the digestive tract, causing indigestion in livestock. This invention, through research, has found that adding appropriate amounts of hydrolyzed tannins to the diet can improve the intestinal immunity of sika deer, and sika deer exhibit a natural tolerance to tannins. The method of this invention has the following advantages: (1) Significantly improve the diversity and richness of gut microbiota: Studies have shown that after adding 0.8% hydrolyzed tannin to the diet, the ACE index, Chao1 index, Observed species index and Shannon index of the gut microbiota of sika deer were all improved, indicating that the diversity and richness of gut microbiota were improved, which is conducive to maintaining the balance of gut microecology.

[0008] (2) Optimization of gut microbiota structure: At the genus level, the relative abundance of *UCG-005*, *Lachnospiraceae* NK4A136 group, and *Xylanibacter* increased, while the relative abundance of *Bacteroides*, *Alternaria*, and *Rhizobium* decreased. These changes are conducive to promoting fiber digestion and the production of short-chain fatty acids, and improving the intestinal metabolic environment.

[0009] (3) Significantly increased intestinal immunoglobulin levels: After adding 0.8% hydrolyzed tannin to the diet, the levels of IgA and IgG in the feces of sika deer showed a continuous upward trend, indicating that the intestinal mucosal immune function was significantly enhanced. As the first line of defense for intestinal mucosal immunity, the increase in IgA level helps to enhance the intestine's resistance to pathogenic microorganisms.

[0010] (4) Avoid the negative effects of high doses of hydrolyzed tannins: Compared with the treatment group with 2% added tannins, the 0.8% added dose did not lead to a significant decrease in the relative abundance of beneficial gut bacteria (such as Muribaculum intestinale and Oscillibacter valericigenes), thus avoiding the health risks of impairing gut microbiota homeostasis and resistance to inflammatory responses due to excessive tannin intake.

[0011] (5) High safety and simple operation: The food-grade hydrolyzed tannins used in this invention are widely available and cost-controllable. They can be added to concentrated feed without complicated equipment and processes, making them easy to promote and apply in farms. At the same time, feeding tannins outside the sika deer's calving period can avoid the potential adverse effects of tannins on pregnant and lactating does and fawns, ensuring the safety of breeding.

[0012] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0013] Figure 1 These are the results of ASVs analysis of the gut microbiota of sika deer before and after feeding with hydrolyzed tannins; Figure 2 This is a comparison chart of the α-diversity index of gut microbiota in sika deer before and after feeding with hydrolyzed tannins; Figure 3 This is a comparison of the relative abundance of gut microbiota at the genus level in sika deer before and after feeding with hydrolyzed tannins; Figure 4 This is a comparison of the relative abundance of gut microbiota in sika deer at the species level before and after feeding with hydrolyzed tannins; Figure 5 This is a NMDS analysis diagram of the gut microbiota of sika deer before and after feeding with hydrolyzed tannins; Figure 6 This is a graph showing the LEfSe analysis of the gut microbiota of sika deer before and after feeding with hydrolyzed tannins; Figure 7 This is a graph showing the changes in IgA and IgG concentrations in the feces of sika deer fed with different doses of hydrolyzed tannins. Detailed Implementation

[0014] The hydrolyzed tannins used in this invention were purchased from Hunan Xianwei Sunshine Biotechnology Co., Ltd. (standard GB 2760 / production license number SC2014331220572).

[0015] Example 1

[0016] The effects of hydrolyzed tannins on the gut microbiota of sika deer.

[0017] 1. Experimental animals: Seven healthy one-year-old male sika deer of similar age and size were selected from a sika deer farm as experimental subjects.

[0018] 2. Dietary treatment: Add 20g of food-grade hydrolyzed tannin (approximately 2% of the diet) to the concentrate feed and feed continuously for 1 month.

[0019] 3. Sample Collection: Fresh fecal samples were collected for 7 consecutive days before the start of the feeding experiment as a control. During the feeding process, fresh fecal samples were collected every 2 days. The fecal samples before tannin feeding (A) and the last fecal sample before the end of feeding (B) were subjected to 16S rRNA high-throughput sequencing for differential analysis.

[0020] 4. Sequencing and analysis results: (1) ASVs analysis The gut microbiota of patients fed tannins and those not fed tannins contained a total of 799 ASVs. After tannin feeding, 1117 ASVs were specific to tannins, compared to 847 in the absence of tannins. (See [link to relevant information]). Figure 1 .

[0021] (2) α-diversity analysis Alpha diversity indices, including Observed species, Chao1, ACE, Shannon, Simpson, and Pielou_J, were calculated using R language. Alpha diversity analysis of gut microbiota was performed before and after feeding. Results are shown below. Figure 2 The results showed that, compared with the gut microbiota before tannin feeding, the ACE index, Chao1 index, Observed species index, and Shannon index were all slightly higher after feeding, while the Pielou J index and Simpson index were slightly lower, but the differences were not significant. Overall, compared with the pre-feeding levels, the gut microbiota after tannin feeding was more diverse and richer, but less evenly distributed.

[0022] (3) Analysis of microbial community structure At the phylum level, there was no significant difference before and after feeding. At the genus level ( Figure 3 At the species level, the relative abundance of *UCG-005*, *Lachnospiraceae* NK4A136 group, and *Xylanibacter* increased after feeding, while the relative abundance of *Bacteroides*, *Alistipes*, and *Muribaculum* decreased, with *Muribaculum* showing a significant decrease. Figure 4 On the sika deer diet, the relative abundance of *Muribaculumintestinale* and *Oscillibacter valericigenes* Sjm18-20 was significantly reduced after feeding. This indicates that while adding 2% tannin to the diet improved the diversity of the gut microbiota, it also reduced the relative abundance of certain beneficial gut bacteria, potentially impairing the ability to maintain gut microbiota homeostasis and resist inflammatory responses, thus posing a health risk.

[0023] (4) NMDS analysis and LEfSe analysis NMDS analysis was performed to assess gut microbiota diversity before and after feeding. Figure 5 The study found that after one month of a diet supplemented with 2% tannins, the gut microbiota underwent a certain degree of differentiation. LEfSe analysis was performed on both groups. Figure 6 Analysis of the core bacterial communities showed significant differences, revealing that before feeding, the dominant bacteria were Sphingomonas, while after feeding, the dominant bacteria were Acidaminococcaceae, Fibrobacteraceae, and Akkermansia.

[0024] Example 2

[0025] Effects of different doses of hydrolyzed tannins on intestinal immunity in sika deer.

[0026] 1. Experimental animals and grouping: Ten healthy one-year-old male sika deer of similar age and size were selected from a sika deer farm as experimental subjects and randomly divided into two groups: Group 1 with 5 individuals and Group 2 with 5 individuals.

[0027] 2. Dietary treatment: Add 20g of food-grade hydrolyzed tannin (approximately 2% of the diet) to the concentrate feed of group 1, and add 8g of food-grade hydrolyzed tannin (approximately 0.8% of the diet) to the concentrate feed of group 2. Both groups were fed continuously for 1 month.

[0028] 3. Sample Collection: Fresh feces were collected every two days during the feeding process. Immunoglobulins were extracted from the last fecal sample collected before the end of feeding for Group 1 (diet supplemented with 2% tannin) and Group 2 (diet supplemented with 0.8% tannin).

[0029] 4. Detection method: The concentrations of immunoglobulins IgA and IgG extracted from feces were determined using the ELISA method.

[0030] 5. Results Analysis: (1) IgA Levels: The overall IgA levels of both groups of sika deer increased within one month. The IgA levels of the sika deer with a diet supplemented with 20g tannin (2%) showed an initial slight decrease followed by a slow increase; the IgA levels of the sika deer with a diet supplemented with 8g tannin (0.8%) showed a continuous upward trend and were generally higher than those of the 2% tannin group. Figure 7 ).

[0031] (2) IgG level: The IgG level of sika deer supplemented with 20g tannin (2%) showed a decrease, while the IgG level of the 0.8% tannin group remained on the rise. Figure 7 ).

[0032] This indicates that adding 2% tannin to the diet has a certain degree of interference with the intestinal immunity of sika deer, while adding 0.8% tannin to the diet has a positive effect on the intestinal immunity and overall immunity of sika deer.

[0033] Example 3

[0034] Optimal feeding program.

[0035] Based on the results of the above embodiments, the optimal feeding program of the present invention is determined to be: adding 0.8% food-grade hydrolyzed tannin to the daily diet of sika deer, uniformly mixing the hydrolyzed tannin into the concentrate feed, and feeding continuously for 1 month. Feeding should be avoided during the sika deer's parturition period to prevent adverse effects on pregnant and lactating does and fawns.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for improving intestinal immunity in sika deer by feeding hydrolyzed tannins, characterized in that, Add 0.8% hydrolyzed tannin to the diet, avoiding the gestation period of the sika deer.

2. The method according to claim 1, characterized in that, The hydrolyzed tannins are food-grade hydrolyzed tannins.

3. The method according to claim 1, characterized in that, The sika deer in question is a 1-year-old sika deer.

4. The method according to claim 1, characterized in that, The feeding method involves adding hydrolyzed tannins to the concentrate feed and feeding it continuously.

5. The method according to claim 4, characterized in that, The continuous feeding period is 1 month.

6. The method according to claim 1, characterized in that, After feeding, the ACE index, Chao1 index, Observed species index and Shannon index of the gut microbiota of sika deer were all increased, and the diversity and richness of gut microbiota were improved.

7. The method according to claim 1, characterized in that, After feeding, the levels of IgA and IgG in the feces of sika deer showed a continuous upward trend, and the intestinal mucosal immune function was enhanced.

8. The method according to claim 1, characterized in that, After feeding, the relative abundance of bacteria of the genus UCG-005, genus Lachnospiraceae NK4A136 group, and genus Xylanibacter in the intestines of sika deer increased.

Images