Effect of Low Protein Diet Supplemented with Amino Acids on the Reproductive Performance,Change of Backfat Thickness and Milk Composition of Lactating Sows

The objective of the study were to investigate the effects of low protein diets supplemented with amino acids on the reproductive performance,change of backfat thickness and milk composition of the lactating sows.35 crossbred sows with similar parity,body weight and body conditions were selected and randomly divided into 3 treatments and each treatment had 13,11 and 11 sows,respectively.A single-factor experimental design was used.Pigs in control group were fed conventional commercial diet with CP level of 17.7%,and the pigs in experimental groupⅠand Ⅱ were fed the diets supplemented with amino acids,and their CP level were 15.7% and 13.7%.The amino acid concentrations were the same in all three diets.The lactation length was 21 days.The results showed that:①Compared with control group,the total litter weight at 21 days,feed intake of lactating sows,survival rate and feed intake of piglets in the experimental groups had no significant difference（P>0.05).With the decrease of protein level,sows' body weight loss increased,but the differences were not significant among the treatments（P>0.05).②With the decrease of protein level,the ratio of sows' reduced fat thickness declined,but the differences among the treatments were not significant(P>0.05).③The milk composition of sows in experimental group Ⅱ was better than that in the control group,but the difference was not significant（P>0.05).The results indicated that using the diets with reduced CP level（from 17.7% to 15.7% or 13.7%）and supplemented with amino acids did not affect the performance of sows and piglets,and it would be an effective measure saving protein resource.