Effect of Valine to Lysine Ratio in Low-protein Diet on Cytokine and Microorganisms in the Milk of Multiparous Sows

WEI Siyong; GU Fang; YE Xiangyang; Yang Xuefen; WANG Li; XIAO Hao; Dong Chunlin

doi:10.19978/j.cnki.xmsy.2025.05.03

Abstract：To reduce feed costs,improve the breeding efficiency of sows,and promote sustainable development in the pig industry,this study investigated the effects of varying valine to lysine(Val/Lys)ratios in low-protein diets on the immune function of sows and the microbiota in their milk.Sixty sows with similar body conditions and mating times(fourth parity Landrace×Large White)were selected as the experimental subjects.The minimum nutritional requirements for lactating sows per NRC standards were used as the standard for low-protein diets.The sows were randomly divided into six groups:a normal protein group(17%CP,Val/Lys=0.87)and five low-protein diet groups(14.3%CP,Val/Lys ratios of 0.64,0.74,0.84,0.94,and 1.04).Each sow was accompanied by 12 piglets,and the experiment lasted from the first day of lactation to the 21st day of weaning,a total of 21 days.The results showed that low-protein diets without additional valine decreased(P<0.05)the abundance of the B-cell marker CD11b in the mammary glands of sows,while increasing the Val/Lys ratio in low-protein diets increased(P<0.05)the abundance of CD11b in the mammary glands.Low-protein diets without additional valine decreased(P<0.05)the concentration of SIgA in colostrum,while increasing the Val/Lys ratio in low-protein diets increased(P<0.05)the concentration of SIgA in colostrum.Low-protein diets without additional valine significantly decreased(P<0.05)the relative abundance of Bacteroidetes,Fusobacteria,and Acidobacteria at the phylum level and Fusobacterium and Staphylococcus at the genus level in the milk microbiota of lactating sows,while increasing the Val/Lys ratio in low-protein diets increased the relative abundance of these microbiotas.In conclusion,low-protein diets without additional valine impair the cytokine and microbial diversity of sows,and increasing the Val/Lys ratio in low-protein diets can mitigate these negative effects and help maintain the production performance of sows.