| Poultry is a warm-blooded animal.When the external temperature exceeds the upper limit of its suitable temperature,it will show symptoms of heat shock.High temperature lasts for a long time in summer in western Guangdong,and large-scale broiler breeding is vulnerable to heat shock,which causes great economic losses.Existing studies have shown that broiler chickens exposed to high temperature for a long period of time will result in reduced food intake,decreased feed conversion,increased abdominal fat deposition and reduced immune performance.At present,the adverse effects of high temperature on the large-scale production of broilers are alleviated mainly by means of nutrition regulation.The study is consistent of two parts.The first part investigates the effects of additional different amount of betaine in diet on the immune organ index,Newcastle disease antibody titer,immune protein concentration and pro-inflammatory factor concentration of Huaixiang rooster in brooding period,clarify the effect of betaine in diet on the immunity of Huaixiang rooster in brooding period.This study choose 2881 day old Huaixiang roosters,randomly divided into control group and 3 betaine group.Control group was feed with basic diet,the betaine groups was feed with basic diet supplemented with 500 mg/kg,1000 mg/kg or 2000 mg/kg betaine respectively.The experiment last 28 days,and the results are as following:Compared to control group,the immune organ index of groups feed with basic diet supplemented with betaine was increased,but not significantly(P>0.05).Adding betaine in basic diet can significantly increase the immune response level of Huaixiang rooster in brooding period.Compared to control group,the newcastle disease antibody titer of group III feed with basic diet supplemented with 2000 mg/kg betaine significantly increased at 21 day and 28 day.Betaine can increase the concentration of immune protein in the serum and duodenal mucosa of Huaixiang rooster in brooding period,and reduce the concentration of pro-inflammatory factor.Compared to control group,at 28 day,the Ig M in plasma of group III feed with basic diet supplemented with 2000 mg/kg was increased 14.11%(P<0.05),the SIg A concentration in intestine mucosa of group II feed with basic diet supplemented with1000 mg/kg betaine increased 13.61%(P<0.05),the IL-6 in plasma of group II was decreased 11.05%(P<0.05).Among the distinct betaine amount,1000 mg/kg is the optimal amount.The second part of this study investigated the effect of supplemented betaine in diet on the immunity of Huaixiang rooster at high temperature environment.This study investigate the effect of sustained high temperature on the immunity of Huaixiang rooster by comparing immune organ index,immune protein concentration,proinflammatory concentration among the groups.This study choose 240 6 week old Huaixiang roosters,randomly divided into 5 groups as following: NC group,HT group,HT1 group,HT2 group,HT3 group.NC group and HT group were feed with basic diet.The HT1 group,HT2 group and HT3 group were feed with basic diet supplemented with 500 mg/kg,1000 mg/kg or 2000 mg/kg betaine respectively.The experiment last 10 weeks,and the results are as following:High temperature causes heat shock,heat shock could induce damage on immune organs,inhibit synthesis of immune proteins,decrease immunity,thus cause inflammation.With the continuation of high temperature,the inhibitory effect of heat shock on immune function increases gradually.Supplementation of betaine in basic diet could relieve the adverse effect of heat shock on immune organ and immune protein of Huaixiang rooster,inhibit the synthesis of proinflammatory cytokines,early effects of heat shock on immune function due to late heat shock.Among the distinct betaine amount,the immunity of Huaixiang rooster was increased by adding increasing amount of betaine in basic diet,and 2000 mg/kg is the optimal amount. |
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