Study On The Mechanism And Influence On Semen Quality In Xiangxi Bulls Under Summer Damp-Heat Stress By Immunization Against Inhibin

The environmental stress become the harmful factors for livestock breeding and production with the improvement of intensive livestock production.The present study was to research the effects of different damp-heat stress on the semen quality,reproductive hormone and plasma biochemical parameters of Xiangxi bull.In addition,studied the mechanism of action of immunization against inhibin to prevent or reduce the semen quality deteriorated in damp-heat stress of Xiangxi bull.This study helped to make application and promotion of the technology of overcoming the adverse impact of heat stress and improving the sperm quality of Xiangxi bull by immunization against IHN.Firstly,the study was to research the effects of different damp-heat stress on the sperm quality,reproductive hormone and plasma biochemical parameters of Xiangxi bull.The results showed that the THI value from June to August belong to moderate damp-heat stress,THI value belong to mild damp-heat stress in September.During damp-heat stress period,the rectal temperature of bulls was significantly higher than no damp-heat stress period(P<0.05);The respiratory rate of bulls in damp-heat stress was significantlyfaster than no damp-heat stress period(P<0.05);During damp-heat stress period,the volume of ejaculation,density,motility and acrosome integrity rate and of bulls were worse than those in no damp-heat stress,and abnormal sperm rate significantly decreased(P<0.05).These results suggest sperm quality of bulls were significantly deteriorated.The serum testosterone(T),FSH and LH concentrations of bulls in damp-heat stress period significantly decreased compared with no damp-heat stress period.the blood routine of bulls were also not affected except for the RBC,HGB,MCH and MCHC were higher and WBC was lower than those in no damp-heat stress period(P<0.05).The concentration of LDH in plasma biochemical index of bulls was increased(P<0.05).The concentration of Glu,TC and T-AOC were lower than those in no damp-heat stress period(P<0.05).While the concentration of ALT and TP is no significant difference(P>0.05).Then the study aimed tomaintain semen quality,which were impaired in bulls adversely affected by summer damp-heat stress,by immunization against inhibin.The results showed that the semen quality were no significant difference in IHN group during experiment period.After immune secondary(56d),the volume of ejaculation,density,motility and acrosome integrity rate of bulls were better than those in control group(P<0.05).After third immune(84d),the volume of ejaculation,density,motility and acrosome integrity rate of bulls were better than those in control group(P<0.05),and abnormal sperm rate significantly decreased than that in control group(P<0.05).After second(56d)and third immune(84d),testosterone concentrations were increased(P<0.05).The testosterone concentrations in IHN group were higher than those in control group after secondary and third immune(P<0.05).After secondary(56d)and third immune(84d),FSH concentrations were increased than 1d and 28d(P<0.05).The FSH concentrations in IHN group were higher than those in control group after secondary and third immune(P<0.05).The LH concentrations in 84 d were increased than those in 1d(P<0.05).The LH concentrations in IHN group were higher than those in control group after secondary and third immune(P<0.05).After immunization against inhibin,the blood routine of bulls were also not affected except for the RBC,HGB and MCH in 84 d were higher than those in 1d(P<0.05).While there were no significant difference with IHN group and control group(P>0.05).The concentration of ALT and TP in plasma biochemical index of bulls were no significant difference in different group and in different IHN immune period(P>0.05).The concentration of LDH was not significant different after immunization against inhibin(P>0.05).But after third immune(84d),the concentration of LDH in IHN group were lower than that in control group(P<0.05).The concentration of Glu was not significant different after immunization against inhibin(P>0.05).But after second(56d)and third immune(84d),the concentration of Glu in IHN group were higher than that in control group.The concentration of Glu was not significant different after immunization against inhibin(P>0.05).But after the third immune(84d),the concentration of Glu in IHN group were higher than those in control group.This study suggest that the semen quality deteriorated in damp-heat stress of Xiangxi bull.Immunization against inhibin can keep sex hormone concentrations and maintain spermatogenesis,which prevent or reduce the semen quality deteriorated in damp-heat stress of Xiangxi bull.