Effect Of Low Protein Diets Supplemented With Balanced Essential Amino Acids On Sows And Barrows In The Growing-finishing Phase

Based on net energy and digestible amino acid systems in this experiment,the effects of low protein diets by reducing 4 percent which were supplemented of 6essential amino acids on the performance,digestibility,slaughter and meat quality,serum and liver biochemical indicators,and intestinal microbes for sows and barrows in the growing-finishing phase were studied.48 “DLY” crossbred pigs about 68 kg were selected and divided into 4 groups according to genders and protein levels: high protein and sow group(SHP),low protein and sow group(SLP),high protein and barrows group(BHP)and low protein and barrows group(BLP).There are 12 replicates per group,and 1 pig per replicate.The period was 51 d.At the end of the feeding experiment,32 pigs were slaughtered and collected relevant tissue samples.The main results are as follows:1.Compared with the high protein diet group,The low protein diet had no significant effects on the ADG and ADFI(P>0.05),significantly improved F/G of pigs(P<0.05).Compared with the SHP group,the ADG and ADFI of the BHP increased by 17.40% and 19.65%,respectively(P<0.05);Compared with the SLP group,the ADG and ADFI of the BLP increased by 16.01%(P<0.05)and 13.54%(P<0.05).Compared with the BHP group,the digestibilities of CP,Ash and P of the BLP were also significantly decreased(P<0.05),and the EE digestibility was significantly increased(P<0.05),too.This indicated the low protein diet significantly affected some nutrient digestibility.Compared with the SHP group,the digestibilities of CP,Ash and P of the SLP were significantly decreased(P<0.05),and the EE digestibility was significantly increased(P<0.05);2.Compared with the high protein diet group,the low protein diet had no significant effects(P>0.05)on the index of slaughter performances and meat qualities.Compared with the SHP group,the backfat thickness of the BHP group was increased by 24.33%(P<0.05),and the final p H value became larger by 1.4%(P<0.05).Compared with the SLP group,the backfat thickness of the BLP group was increased by 11.73%(P<0.05),and the final p H value became larger by 1.6%(P<0.05).3.The Glu contents and SOD activity of serum in the BLP group is higher than the BHP group(P<0.05).Compared with the SHP group,the total protein content of serum in the BHP group was decreased(P<0.05).Compared with the SLP group,the serum contents of total protein and Glu and acetylformic acid content in the BLP group were increased(P<0.05).4.Compared with the SHP group,the NEFA content of liver in the SLP group was increased(P<0.05).Compared with the BHP group,the NEFA content was increased(P<0.05),the contents of acetylformic acid and MDA were decreased(P<0.05).The Glu content of the BHP group was lower than the SHP group(P<0.05).The contents of acetylformic acid and Glu and MDA in the BLP was lower than the SLP group(P<0.05).5.Compared with the high protein group,the indices of Simpson and Shannon in the low protein sow and barrow groups was increased by 1.0%,1.4%,and 10.2%,2.9%,respectively;The dominant bacteria Streptococcus in the low protein groups was increased;In the principal component analysis,there were significant differences in the clustering regions between the high protein groups and the low protein groups.In conclusion,our experiments demonstrated that low protein diet could improve the F/G of growing-finishing pigs,and have no significant effects on the slaughter performances and meat qualities.Futhermore,low protein diet has significant effects on some nutrient digestibility and could improve the metabolism and antioxidation and the structures of intestinal microbiota.