PDF(Pubmed)
Abstract：
The nutritional benefits of mare milk are attracting increasing consumer interest. Limited availability due to low yield poses a challenge for widespread adoption. Although lysine and threonine are often used to enhance protein synthesis and muscle mass in horses, their impact on mare milk yield and nutrient composition remains underexplored. This study investigated the effects of lysine and threonine supplementation on 24 healthy Yili mares, mares at day 30 of lactation, over a 120-day period. The mares were divided into control and three experimental groups (six mares each) under pure grazing conditions. The control group received no amino acid supplementation, while experimental groups received varying daily doses of lysine and threonine: Group I (40 g lysine + 20 g threonine), Group II (60 g lysine + 40 g threonine), and Group III (80 g lysine + 60 g threonine). Supplementation in Group II notably increased milk yield, while Groups I and II showed higher milk fat percentages, and all experimental groups exhibited improved milk protein percentages. Additionally, blood levels of total protein, albumin, triglycerides, and glucose were reduced. Detailed analyses from Group II at peak lactation (day 60) included targeted metabolomics and microbial sequencing of milk, blood, and fecal samples. Amino acid metabolomics assessed amino acid content in mare milk and serum, while 16S rRNA gene sequencing evaluated rectal microbial composition. The results indicated that lysine and threonine supplementation significantly increased levels of threonine and creatine in the blood, and lysine, threonine, glutamine, and alanine in mare milk. Microbial analysis revealed a higher prevalence of certain bacterial families and genera, including Prevotellaceae, p_251_o5, and Rikenellaceae at the family level, and unclassified_p_251_o5, Prevotellaceae_UCG_001, and Rikenellaceae_RC9_gut_group at the genus level. Multi-omics analysis showed positive correlations between specific fecal genera and amino acids in mare milk. For instance, Prevotellaceae_UCG_003, unclassified Bacteroidetes_BS11_gut_group, and Corynebacterium were positively correlated with lysine, while unclassified Prevotellaceae was positively correlated with alanine and threonine, and Unclassified_Bacteroidales_BS11_gut_group was positively correlated with glutamine. In summary, lysine and threonine supplementation in grazing lactating mares enhanced milk production and improved milk protein and fat quality. It is recommended that herders, veterinarians, and technicians consider amino acid content in the diet of lactating mares. The optimal supplementation levels under grazing conditions for Yili horses were determined to be 60 g lysine and 40 g threonine per day. Future research should explore the molecular mechanisms by which these amino acids influence milk protein and lipid synthesis in mare mammary epithelial cells.
摘要：
马奶的营养益处正在吸引越来越多的消费者的兴趣。低产量导致的有限可用性对广泛采用提出了挑战。尽管赖氨酸和苏氨酸通常用于增强马的蛋白质合成和肌肉质量，它们对马奶产量和营养成分的影响仍未得到充分研究。这项研究调查了补充赖氨酸和苏氨酸对24只健康伊犁母马的影响，哺乳期第30天的母马，超过120天。在纯放牧条件下，将母马分为对照组和三个实验组（每组六匹母马）。对照组不补充氨基酸，而实验组每天接受不同剂量的赖氨酸和苏氨酸：I组（40克赖氨酸+20克苏氨酸），II组（60克赖氨酸+40克苏氨酸），和组III(80g赖氨酸+60g苏氨酸)。第二组的补充显著增加了产奶量，而第一组和第二组显示出较高的乳脂百分比，并且所有实验组都表现出改善的乳蛋白百分比。此外,总蛋白质的血液水平，白蛋白,甘油三酯，和葡萄糖减少。第II组泌乳高峰期（第60天）的详细分析包括靶向代谢组学和牛奶的微生物测序，血,和粪便样本。氨基酸代谢组学评估了马奶和血清中的氨基酸含量，而16SrRNA基因测序评估直肠微生物组成。结果表明，补充赖氨酸和苏氨酸会显著增加血液中苏氨酸和肌酸的水平，还有赖氨酸,苏氨酸,谷氨酰胺,和马奶中的丙氨酸.微生物分析显示某些细菌家族和属的患病率较高，包括Prevotellaceae,p_251_o5，和Rikenellaceae在家庭水平，在属水平上未分类的_p_251_o5，Prevotellaceae_UCG_001和Rikenellaceae_RC9_gut_组。多组学分析表明，特定粪便属与马奶中的氨基酸呈正相关。例如,Prevotellaceae_UCG_003，未分类的拟杆菌_BS11_gut_组，棒状杆菌与赖氨酸呈正相关，未分类的Prevotellaceae与丙氨酸和苏氨酸呈正相关，未分类的类杆菌群与谷氨酰胺呈正相关。总之,在放牧泌乳母马中补充赖氨酸和苏氨酸可提高牛奶产量并改善牛奶蛋白质和脂肪质量。建议牧民，兽医,技术人员考虑泌乳母马饮食中的氨基酸含量。确定伊犁马在放牧条件下的最佳补充水平为每天60g赖氨酸和40g苏氨酸。未来的研究应探索这些氨基酸影响母乳上皮细胞中乳蛋白和脂质合成的分子机制。
