| This study aims to explore glutamine(Gln)oral administration before transportation alleviate chicks intestinal oxidative damage by transport stress and related mechanism.And evaluated by growth performance,intestinal morphology,the body’s antioxidant ability,mitochondrial function,necrotizing apoptosis signaling pathways critical factor expressed.It is of great significance to development of functional amino acid enhance antioxidant capacity,alleviate the transport stress.Trial 1:The establishment of transport stress modelA total of 120 AA healthy newborn chicks were randomly divided into two groups:A and B.Group B was transported for 5 h and group A was not transported for 5 h.The two groups kept the same environment condition:temperature and density etc.After the transportation,serum corticosterone(CORT),adrenocorticotropic hormone(ACTH)contents,and relative expression levels of HSP70 mRNA and protein in jejunal mucosa were determined.The results showed that:5h transport stress significantly increased serum CORT and ACTH hormone levels(P<0.05),and the relative expression levels of HSP70 mRNA and protein in jejunal mucosa were extremely significantly increased(P<0.01).The results showed that the transport stress model was successfully established.Trial 2:Effects of Gln oral administration before transportation on growth performance of chicks under transportation stressA total of 300 AA healthy newborn chicks were randomly divided into 5 groups(5replicates per group and 12 chicks per repitition):A,B,C,D and E.Before transportation,groups A and B were fed with 1ml normal saline solution,and groups C,D and E were fed with1ml Gln normal saline solution at the standard of 0.5g,0.75g and 1g per kg body weight of chicks,respectively.Then groups B,C,D and E were transported for 5h,and all groups were under the same environmental conditions.After the transportation,the chicks were fed for 14days and determine their performance.The results showed that after 5 hours of transportation treatment,weight loss was significant in group B than group A(P<0.05),while no significant weight loss was observed in groups given Gln than group A.At 7 days of age,the average daily gain,average daily feed intake and feed conversion rate of group B were significantly lower than group A(P<0.05),and the average daily gain of chicks fed Gln was significantly higher than that of group B,but still lower than that of control group(P<0.05).The average daily feed intake of chicks fed Gln was significantly improved compared with group B(P<0.05),but there was no significant difference between group D and control group(P>0.05).There was no significant difference in feed conversion between 0.75g/kg Gln treatment group and control group.At 14 days of age,the average daily feed intake,average daily gain and feed conversion rate of group B were still significantly lower than that of group A,and the same indexes of group C,D and E were significantly improved than group B after Gln oral administration.The average daily gain of group D and group E and the average feed intake of group D had reached the control level.The results showed that 5h transportation could lead to serious weightlessness and decreased performance of chicks.Gln oral administration before transportation could effectively alleviate the weightlessness and improve performance.Trial 3.Gln oral administration before transportation can alleviate intestinal oxidative damage of chicks under transport stressAfter transportation,4 chicks were randomly selected from each replicate for slaughter,and cervical venous blood and jejunal mucosa were collected to determine the contents of malondialdehyde(MDA),glutathione peroxidase(GSH-PX),superoxide dismutase(SOD),catalase(CAT)and reactive oxygen species(ROS)in serum and intestinal mucosa.The contents of lactate dehydrogenase(LDH),plasma diamine oxidase(DAO),D-lactose(DLA)in serum also determined.Tissues of duodenum,jejunum and ileum were collected to observe intestinal morphology and structure.The results showed that transport stress could significantly increase the levels of ROS,MDA and LDH(P<0.05),and significantly decrease the contents of GSH-PX,SOD and CAT in group B(P<0.05).The gaps of the above indexes between group A and group C,D and E were significantly narrowed by fed Gln before transportation(P<0.05).The serum ROS concentration in group D could reached the level of control group.The transport stress resulted in the damage,edema,rupture and shedding of the small intestinal villi of chicks in group B,and the damage of intestinal villi was significantly improved after the oral administration of Gln.It is confirmed that transport stress caused oxidative damage in the intestinal tract of chicks.Gln oral administration before transportation could effectively improve the blood hormone level and antioxidant function of chicks,and protect the intestinal mucosal barrier function.Trial 4.Effect of Gln oral administration before transportation on mitochondrial function of intestinal mucosal epithelial cells of chicks under transport stressAfter the transportation,intestinal tissues of jejunum were collected,mitochondria were extracted with the kit,and the contents of mitochondrial membrane potential,ATP,NAD~+and NADH were determined.The results showed that transport stress significantly decreased the mitochondrial membrane potential,ATP content and NAD+in jejunum of chicks in group B(P<0.05),and increased NADH(P<0.05).Compared with group B,Gln oral administration before transportation significantly increased the mitochondrial membrane potential,ATP content and NAD~+(P<0.05),and decreased NADH(P<0.05).It is confirmed that transport stress leads to oxidative mitochondrial damage in the intestinal tract of chicks,resulting in cell apoptosis.Gln oral administration before transportation can effectively improve the mitochondrial function of chicks,reduce cell apoptosis,and reduce stress damage.Trial 5.Effect of Gln oral administration before transportation on the signal pathway of intestinal mucosa necrotizing apoptosis in chickens under transport stress.After transportation,jejunal mucosa was collected to determine the expression of key factors RIPK1,RIPK3 and MLKL in the necrotizing apoptosis signaling pathway.The results showed that transport stress significantly up-regulated the mRNA and protein relative expression levels of RIPK1,RIPK3 and MLKL in group B,and Gln significantly down-regulated the mRNA and protein expression levels of RIPK1,RIPK3 and MLKL in intestinal mucosa compared with group B(P<0.01).Fed Glu also inhibit necrotizing apoptosis pathway,alleviate intestinal oxidative stress,and improve intestinal function.It is confirmed that transport stress significantly increased the key factors of necrotizing apoptosis signaling pathway in chicks,and Gln oral administration before transportation could down-regulate the expression of RIPK1,RIPK3 and MLKL,improve cell apoptosis and alleviate oxidative damage,and 0.75g/kg Gln treatment had a better result. |
