Effects Of Low Protein Diets With Different Source On Growth Performance And Amino Acid Dynamic Change Pattern In Small Intestinal Of Finishing Pigs

Protein is the most important components in animal diets,adequate protein intake can guarantee the growth performance of animal.However,it also increased the feed cost and environment nitrogen pollution.This experiment was supplement with crystalline amino acids(AA)to keep essential AA balance under low protein diet(11%)and investigate the effects of different protein source on growth performance,nitrogen balance,blood biochemical indicators,the dynamic change pattern of free amino acids(FAA)digestion and absorption in small intestinal and related AA transporter expression in finishing pigs.The aim of this study is search proper protein source and provide science theoretical basis for increased protein utilization in production practice of finishing pigs.Forty-eight Duroc × Landrace × Large White finishing barrows(58.65± 1.71 kg)were randomly assigned to four equal groups and four repeat per group,include a normal crude protein(15% CP)soybean meal(SBM15)and three low crude protein(11% CP)diets which were SBM11,soybean-cottonseed-corn germ meal(SCCM11)and cottonseed-corn germ meal(CCM11)respectively.According to standardized ileum digestibility of AA,adding crystalline AA to essential AA balance in diet.The results showed that:1.SBM11 or SCCM11-based diet had no effect on the growth performance of finishing pigs,but,significant increased the digestibility of apparent nitrogen and nitrogen retention(P<0.05).The CCM11 group showed a poor growth performance(P<0.05).The three treatment groups significant reduced faecal nitrogen and urinary nitrogen excreation(P<0.05).2.The content of UREA for SCCM11 group significant lower than SBM15 or SBM11 group.The content of TP,ALB and ALT for CCM11 group significant lower than the other three groups and CHOL significant higher than the other three groups(P<0.05).The GLU among the four groups had no significant difference(P>0.05).3.At 1.5,3.0,and 4.5 h after feeding,the SCCM11 group showed a stable tendency of AA releasing in small intestinal and maintain a high FAA content in portal vein serum.Though,the CCM11 group showed a stable tendency of AA releasing in small intestinal,the content of FAA always showed a low level in portal vein serum.4.The CAT1 expression in duodenum,anterior-jejunum,and ileum of SBM15 group significant higher than the SBM11,SCCM11 and CCM11 groups(P<0.05).However,the SCCM11 group significant increased the expression of EAAC1?CAT1?B0AT1 in post-jejunum and ileum than the CCM11 group,respectively(P<0.05).