Effects Of Heat Shock Protein 70 On Intestinal Structure And Function Of Digestion Of Aa Broilers Under Heat Stress Conditions

In order to investigate the effect of heat shock protein 70 inducers(glutamine) and inhibitors(quercetin) on Arbor Acers broilers under heat stress conditions, some biochemistry indexes of Arbor Acers borilers were studied in this research, such as intestinal mucosa HSP70 and HSP70mRNA expression, intestinal structure, intestinal chyme digestive enzymes activities, serum corticosterone level, total white blood cell count, H/L value, intestinal mucosa alkaline phosphatase(AKP) activity. The experiment was conducted to determine the effects of HSP70 on intestinal structure and function of digestion of AA broilers under heat stress conditions.Two hundred and forty 36-days-old similar weight Arbor Acers broilers were randomly allocated in four groups with 6 replications per group and 10 broilers per replication, and were bred in two environmental chambers which temperature and humidity conditions were consistent. Each chamber was placed with three repetitions of each treatment. Twenty-four hours before the heat stress, the different treatment groups were injected HSP70 inducer (glutamine) and inhibitor (quercetin). Doses were: control group was injected with saline water; inducer group was injected with inducer (glutamine) 0.75g/kg body weight; inhibitor group was injected with inhibitor (quercetin) 5mg/kg body weight; inducer + inhibitor group was injected with inducer (glutamine) 0.75g/kg body weight and inhibitor (quercetin) 5mg/kg body weight. Twenty-four hours after injection all the broilers were exposed to 36℃treatment of acute heat stress. Five time points of heat stress were established: 0, 2, 3, 5, 10 h. At the different heat stress time points, one broiler from the each repetition of each treatment was took out for blood collection to measure total white blood cell count, H/L value and serum corticosterone levels. Then the broilers were slaughtered for intestinal mucosa and intestinal chyme collection to measure expression of HSP70 and HSP70mRNA, intestinal mucosa alkaline phosphatase(AKP) activity, intestinal structure, digestive enzyme activity. The results showed that: (1) The HSP70 and HSP70mRNA expression of broiler intestinal mucosa of inducer group were increased significantly (P<0.05) under heat stress conditions. (2)The effects of experiment treatment and heat stress time on serum corticosterone levels and total white blood cell count were not significant, and H/L value was reduced significantly (P<0.05), the alkaline phosphatase activity of intestinal mucosa and V/C value were increased significantly (P<0.05). The function of digestion of intestinal was maintained by increasing the digestive enzyme activities of jejunal chyme. (3) Impact of heat stress time is also an important factor in the role of HSP70. In short, overexpression of HPS70 can play important role on protection of the intestinal structure and physiological function under heat stress conditions.