Protective Effects Of Glutamine On Growth Performance,Muscle Quality,Oxidative Damage In Broilers Under Cyclic Heat Stress

The effects of glutamine supplementation on growth performance,muscle quality and antioxidant activity of broilers under cyclic heat stress were studied.The test selected 350 broilers of 1 days of age,for 21 days of age,300 healthy AA broilers were selected.They were randomly divided into 5 groups(6 repetitions in each group,10 for each repeat),and the heat stress test was carried out.Group I was a temperature control group(basal diet;temperature:23±2?,relative humidity:45%-55%);group II,III,IV,and V were added to the heat stress group(0%,0.5%,1%,1.5%glutamine,18:00-8:00,temperature:23±2?,relative humidity:45%-55%;9:00-17:00,342±2?)Temperature and relative humidity:60%-70%).The materials were collected according to the experimental design and the related indexes were tested.The results are as follows:1?Effects of glutamine on the performance of broilers under cyclic heat stressAt the age of 28,35 and 42 days,compared with group ?,the average weight gain and average feed intake of broilers in group ? decreased significantly(P<0.05),and the ratio of material weight at 35 days of age increased significantly(P<0.05).In the cycle heat stress group,the average weight gain and average feed intake(P<0.05)were significantly increased at 28 days of age at 28 days of age,and the ratio of feed weight was decreased.The average weight gain and average feed intake of broilers increased significantly(P<0.05)when the 35 day old diets added 1%and 1.5%Gln(P<0.05),and the ratio of feed weight to 1.5%Gln was significantly lower(P<0.05);42 The average weight gain of broilers increased significantly(P<0.05),and the average feed intake increased significantly at 1.5%Gln(P<0.05)when 1%and 1.5%Gln were added to the diet(P<0.05).2?Effects of glutamine on meat quality of chicken under cyclic heat stressCompared with group I,the chest muscles of 28 day old broilers in group ? were 45 min,12 h,24 h,36 h and 45 min,12 h,24 h,72 h pH at each time point of the leg muscles,and 24 h,36 h,72 h and 120 leg muscles were significantly reduced,45 min,12 h,24 h,36 h,72 h and L*in the chest and leg muscles.The loss and water loss rate of the chest and leg muscles increased significantly(P<0.05),the b*value of chest muscle and a*of leg muscle were significantly decreased at 35 days old(P<0.05),and the L*value of breast muscle,cooking loss and leg muscle water loss rate were significantly increased(P<0.05).for 42 days of age,the pH of the chest and leg muscles,the a*and b*of the pectoral muscles and the a*of the leg muscle and leg muscle significantly decreased(P<0.05),and the L*value of the chest and leg muscles,the loss of cooking and the loss of water significantly increased(P<0.05).Compared with group ?,adding 1.5%Gin to diet could significantly improve muscle color,pH value,cooking loss and water loss rate of broilers at 28,35 and 42 days old.3?Effects of glutamine on the oxidation performance of the chest muscle and leg muscles of the broiler under cyclic heat stressCompared with group ?,group ? were significantly reduced the 28 day age of the chest muscles O2-·?T-SOD?GSH?CAT and leg muscle 02-*?T-SOD?GSH,the 35 day age of the chest muscles 02-·?T-SOD?GSH?GSH-Px and leg muscle O2-·?T-SOD?GSH?GSH-Px?CAT,the 42 day age of the chest muscles 02-·?GSH?GSH-Px?CAT and leg muscle 02-·?T-SOD?GSH?GSH-Px?CAT.The MDA values of the pectoral and leg muscles increased significantly(P<0.05).In the cycle heat stress group,the addition of 1.5%Gin to diet could significantly increase the antioxidant index content of the chest and leg muscles of 28,35 and 42 days of age,and reduce the oxidation index content.4?Effects of glutamine on Nrf2 signaling pathway in skeletal muscle of circulating Heat Stressed BroilersCompared with group I,the content of Nrf2 factor of chest muscle in group ? was significantly decreased at 35 days of age(P<0.05),and the content of Nrf2 factor in the chest and leg muscles at 42 days of age was significantly decreased(P<0.05).In the cycle heat stress group,the dietary supplementation of 1.0%-1.5%Gln could significantly increase the Nrf2 factor content(P<0.05)of the 35 day old breast muscle,and the addition of 0.5%-1.5%Gln could significantly increase the content of Nrf2 factor in the leg muscle of 42 days of age(P<0.05).To sum up,cyclic heat stress has many negative effects on chicken body,including growth performance,muscle quality,oxidation performance and signal pathway,thus reducing the efficiency and economic benefit of broiler breeding.Adding Gln in the diet can effectively improve the negative effect of heat stress.The suitable addition concentration is 1.0%-1.5%.Therefore,it can provide a theoretical basis for the application of Gln as a safe nutritional heat stress feed additive in broiler production.