Effects of Methionine Supplementation in Low-Protein Diets on Growth Performance, Fur Quality, Blood Indices, and Intestinal Microbiota of Blue Foxes (Vulpes lagopus) During the Fur-Growing Period

This study on blue foxes (Vulpes lagopus) during the fur-growing period examined the effects of methionine supplementation in low-protein diets on growth performance, fur quality, blood indices, and intestinal microbiota. Conducted over 70 days with 50 foxes, the study found that methionine supplementation (0.35%, 0.55%, and 0.75%) improved growth parameters, with the highest level (0.75%) restoring growth to control levels. Methionine also enhanced fur quality, nutrient digestibility, and protein utilization efficiency, while reducing nitrogen excretion. The intestinal microbiota showed increased diversity with higher methionine levels, indicating a restructuring of microbial communities. Overall, methionine supplementation in low-protein diets effectively maintained or enhanced fur quality and supported growth performance, suggesting its potential for practical application in animal production.