Effects Of Glutamine On Protein Synthesis And Degradation In Liver And Muscle Of Immune Stress Broilers

This trial was conducted to investigate the effects of glutamine(Gln)supplementation in dietary on growth performance,blood parameters,protein synthesis and degradation in liver and muscle of broilers induced by lipopolysaccharide(LPS).A total of 120 1-d Avian broilers(half of the male and female)were arranged in a 2×2 factor design and randomly allotted into 4 experimental treatments with 5 replicates per treatment of 6chicks.Group A: control group was fed diet and saline injection;Group B: control group diet and LPS injection;Group C: trial group was fed diet and saline injection;Group D: trial group was fed diet and LPS injection.The trial diet was supplemented with 1.0% Gln in the basal diet to balance the nitrogen level in the diet.In this study,1.22% alanine(Ala)was added to the basal diet as a control diet.500 μg/kg BW of LPS or an equivalent volume of saline was intraperitoneally injected at 8:00 am on the 16 th and 21 st day.The experiment lasted for 21 days.Feeds and leftovers were daily recorded,in order to perform the calculation of the average daily feed intake,average daily weight gain and feed-to-weight ratio by weighing on an empty stomach before morning feeding on 1,15,16 and 21 days of study.And slaughter samples were collected for subsequent analysis at 21 d after 2 h LPS injection.The experimental results are as follows:1、Effect of Gln on growth performance and blood biochemical parameters of immune stress broilersThe results showed that LPS challenge significantly decreased 21-day-old weight,ADFI and ADG,and significantly increased F/G of broilers(P<0.05),while 1.0% Gln supplementation significantly increased 21-day-old weight,ADFI and ADG,and significantly decreased F/G of broilers(P<0.05).LPS challenge significantly improved the contents of TNF-α,IL-1β,IL-6 and UA in plasma of broilers(P<0.05),in contrast,1.0% Gln supplementation significantly decreased the plasma TNF-α,IL-1β,IL-6 and UA contents of broilers(P<0.05).These results suggest that Gln supplementation in dietary had a protective effect on the growth of broilers.2、Effect of Gln on protein synthesis and degradation signals in liver and muscle of immune stress broilersThe results showed that LPS challenge significantly increased AST and GS activity and GLS m RNA expression levels in broiler liver(P<0.05),significantly decreased AST activity in muscle(P<0.05)and significantly increased GLS m RNA expression level(P<0.05).1.0% Gln supplementation in dietary significantly decreased GS activity and GLS m RNA expression levels in broiler liver(P<0.05),and significantly increased AST and GS activity in muscle.LPS challenge significantly increased liver CP,CRP and SAA expression in broilers(P<0.05),while1.0% Gln supplementation in dietary significantly decreased the expression of CP,CRP and SAA(P<0.05).m TOR,4E-BP1 and S6K1 m RNA expression levels were significantly decreased by LPS challenge(P<0.05).1.0% Gln supplementation in dietary significantly increased m TOR,4EBP1 and S6K1 m RNA expression levels(P<0.05).In addition,LPS challenge significantly decreased Akt m RNA expression levels(P<0.05)and significantly increased TLR4,FOXO4,FOXO1,MAFbx and Mu RF1 m RNA expression levels(P<0.05).1.0% Gln supplementation in dietary significantly increased Akt m RNA expression levels(P<0.05)and significantly decreased TLR4,FOXO4,FOXO1,MAFbx and Mu RF1 m RNA expression levels(P<0.05).These results suggest that Gln supplementation in dietary alleviated muscle protein degradation due to LPS challenge via the Akt/FOXO/UPP signaling pathway and the m TOR signaling pathway.