Effects of lysine and threonine on milk yield, amino acid metabolism, and fecal microbiota of Yili lactating mares.
Authors: Lin Jianwei, Jing Hongxin, Wang Jianwen, Lucien-Cabaraux Jean-Francois, Yang Kailun, Liu Wujun, Li Xiaobin
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: Lysine and Threonine Supplementation in Lactating Mares Mare milk production remains limited by relatively low yield despite growing commercial and nutritional interest, yet few studies have systematically examined how targeted amino acid supplementation might enhance lactational performance. Over 120 days, researchers allocated 24 Yili mares (30 days into lactation) across control and three treatment groups receiving escalating doses of lysine and threonine (40/20 g, 60/40 g, and 80/60 g daily respectively), with detailed metabolomic and microbial profiling conducted at peak lactation. The moderate supplementation protocol (60 g lysine + 40 g threonine) proved most effective, significantly increasing milk yield whilst improving protein and fat percentages across all treatment groups; concurrently, blood glucose, triglycerides, albumin and total protein decreased, suggesting improved nutrient partitioning towards lactation. Metagenomic analysis revealed enhanced fecal populations of Prevotellaceae and Rikenellaceae alongside elevated serum threonine and creatine, with multi-omics integration demonstrating positive correlations between specific bacterial taxa (particularly Prevotellaceae_UCG_001 and Corynebacterium) and elevated milk amino acids including lysine, alanine, and glutamine. For practitioners managing lactating mares on pasture-based systems, implementing moderate daily supplementation of 60 g lysine and 40 g threonine represents an evidence-supported strategy to enhance both production volume and milk composition quality, though the underlying mechanisms governing mammary amino acid uptake and synthesis warrant further investigation.
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Practical Takeaways
- •For herds focused on mare milk production, consider supplementing 60g lysine + 40g threonine daily to grazing mares to increase yield and improve milk protein/fat quality
- •Monitor amino acid balance in lactating mare diets—targeted supplementation can enhance milk composition without requiring grain supplementation under grazing conditions
- •Gut microbiota changes correlate with improved milk amino acid profiles, suggesting that amino acid supplementation may optimize digestive efficiency in lactating mares
Key Findings
- •Supplementation with 60g lysine + 40g threonine daily (Group II) significantly increased milk yield in grazing Yili mares
- •All experimental groups showed improved milk protein percentages, with Groups I and II exhibiting higher milk fat percentages
- •Lysine and threonine supplementation increased threonine and creatine in blood serum and lysine, threonine, glutamine, and alanine in mare milk
- •Specific fecal bacterial genera (Prevotellaceae_UCG_003, unclassified Bacteroidetes, Corynebacterium) showed positive correlations with elevated amino acids in milk