Effects Of Acidic Amino Acids On Growth Performance In Weaned Piglets

Acidic amino acids are one of the important sources of energy for small intestinal including glutamate(Glu)and aspartic acid(Asp).Glu and Asp can be decarboxylation or transamination into other substances and play an important role to maintain the normal function of the intestinal tract,hormone secretion,antioxidant capacity,nerve regulation and immunity.Free amino acids into the small intestine after being oxidized as part of the energy to maintain intestinal function and structure,part of the small intestine selectively absorbed into the mesenteric vein.Mesenteric vein and left gastric vein,splenic vein and other converge to the portal vein.With decreased protein diets by 3% and balancing four essential amino acids had no significant effect on the performance of weaned piglets.Thus this paper was to evaluate effects of dietary decreased the level of crude protein with balancing the four essential amino acids and added different contents of glutamic acid(Glu)and aspartic acid(Asp)on growth performance of weaned piglets.Forty-two weaned piglets were randomly divided into one of six groups(n=7): a control group in which piglets fed 2.9% Glu and 1.5% Asp according to NRC(2012)standard and other groups in which piglets received 2.6%,3.2%,and 3.5% Glu and 1.3% and 1.7% Asp with dietary crude protein levels were 17%.Measurement include the growth performance of weaning piglets,the biochemical indicators of serum and the level of hormones.Serum amino acids of the anterior vena cava、mesenteric serum、hepatic portal vein and dopamine transporter of jejunum mucosa.The results showed that:1.Lower Asp promotes growth and amino acids pool while high Asp and Glu(HA,HG and HHG group)inhibits growth and amino acid pool in piglets(P<0.05).2.Dietary different dosage of Glu and Asp failed to affect serum Lys,Met,Thr,Asp,Phe,Ser,His,Gly,Ala,and Pro concentration in serum of mesenteric vein,portal vein serum and anterior vena cava(P>0.05).In the portal vein,Trp and Tyr abundance in LA group were markedly higher than HA group(P<0.05).Trp and Glu levels was similarly tends in the anterior vena cava(P<0.05).Ile levels in the mesenteric serum,Val,Ile and Leu concentration in the portal vein,Ile,Leu and Arg in the anterior vena cava in HG group were higher than HHG group(P<0.05).3.Low and high dosage Asp levels were significantly down-regulation jejunum mucosa SLC1A1 and SLC71 expression.The expression of SLC7A7 in jejunal mucosa was markedly inhibited with dose-dependent manner and the expression abudance of SLC6A19 was enriched with dose-dependent manner.Low-dose Glu or high-dose Glu significantly inhibite the expression of SLC1A1 in jejunum mucosa.High-dose Glu significantly down-regulated the expression of SLC7A1.Low-dose and high-dose Glu levels were significantly up-regulated in SLC6A19,especially in low-dose glutamate groups.4.TG in LA group and NC group were significantly lower than the HA group(P <0.05).ALB in LG group were significantly lower than the HHG group and the HG group(P < 0.05).GLU in LG group and the HG group were markedly lower than the HHG group.Serum TG in HG group and the HHG group was significantly lower than that in LG group(P <0.05).5.The GIP concentration in HA group was significantly lower than the LA group(P <0.05).Serum levels of INS in LG group and the HG group were significantly higher than the HHG group(P <0.05).While,the blood GC trend was similar,LG group,HG group was significantly lower than the HHG group(P <0.05);The serum growth hormone concentration in LG and HG groups was significantly lower than the HHG group(P <0.05).From the above,when the contents of Asp and Glu in the diets were 1.3%-1.5% and 2.6%-2.9%,the production performance of weaning piglets was better and the absorption and metabolism of amino acids were more abundant.The high levels of Glu and Asp,especially 3.2% Glu might be inhibition the production,amino acid metabolism and blood physiological and biochemical.