| At present,the main rearing modes of breeders are single cage and colony cage systems,and there are many studies on the reproductive performance of hens and technological parameters of cage with these two modes,but few studies on the reproductive performance of cocks under these two modes have been reported.Previous studies have found that spermatogenic cell apoptosis in male spermatogenesis is closely related to semen quality and fertility.Therefore,it is great significance for breeding poultry production to study the semen quality and spermatogenic cell apoptosis of cocks under different feeding modes.In this experiment,Rohmann parental chickens were adopted as the research animals.To explore the effects of different feeding methods on testicular development,semen quality and spermatogenic cell apoptosis of breeding cocks.The difference of testicular development and the changes of plasma main reproductive hormones between the growing period and the peak period of sexual maturity of cocks in colony cage,single cage and large cage were compared.The differences of routine semen quality indexes,apoptosis of testicular spermatogenic cells and sperm apoptosis of breeding cocks under three feeding modes during the peak period of sexual maturity were compared.The main results are as follows:(1)The result of testicular development determination in growing period to sexual maturity period show that: at the age of 10 weeks,the seminiferous tubules of each group were closed;at the age of 15 weeks,the official cavity appeared in the seminiferous tubules of each group,and at the age of 20 weeks,spermatogenesis began in the seminiferous tubules of each group.The 10-20 weeks are the period of rapid testicular development of cocks.At the age of 30 weeks,the relative testicular weight and spermatogenic tubule area of cocks in the colony cage group were significantly higher than those in the single cage group and the large cage group(P < 0.05).(2)The result of plasma reproductive hormones determination in growing period to sexual maturity period show that: The contents of T,GnRH,FSH and LH in plasma of cocks in each group increased with the increase of age,while the contents of E2 decreased with the increase of age.At the age of 30 weeks,the plasma T,GnRH,FSH and LH levels in the colony cage group were significantly higher than those in the single cage group and the large cage group(P < 0.05),while the plasma E2 levels in the colony cage group were significantly lower than those in the single cage group and the large cage group(P < 0.05).(3)The results of semen quality determination in sexual maturity period showed that: at the age of 25 weeks,there were no significant differences in semen volume,pH,sperm density,motility,and viability among the three groups(P > 0.05);at 30 weeks of age,the semen volume,sperm density and sperm viability of the cross cage group were significantly higher than those of the single cage group and the large cage group(P < 0.05).(4)The results of spermatogenic cell apoptosis determination of testicular tissue in sexual maturity period showed that: at the age of 25 weeks,there was no significant difference in apoptotic degree and relative expression of apoptotic genes among the three groups(P > 0.05).At the age of 30 weeks,the apoptotic degree and relative expression of apoptotic genes Caspase 8,Caspase 3,and P53 in testicular tissue of the colony cage group were significantly lower than those of the single cage group and the large cage group(P < 0.05),and the anti-litter ability of testicular tissue of the colony cage group was also significantly lower than those of the single cage group and the large cage group(P < 0.05).The expression levels of Bcl-2 and Bcl-xl were significantly higher in single cage group than those in large cage group(P < 0.05).(5)The results of apoptotic protein localization and expression of testicular tissue in sexual maturity period showed that: at the age of 25 and 30 weeks,Caspase-3 apoptotic protein was expressed in Sertoli cells,spermatogonia,primary spermatocyte,and secondary spermatocyte of three groups roosters,and was highly expressed in spermatogonia and spermatocyte of three groups roosters,but not in spermatocyte.Bcl-2 anti-apoptotic protein was expressed in spermatogonia,primary spermatocyte,secondary spermatocyte,and spermatocyte of three groups roosters.At the age of 30 weeks,the total optical density of Caspase-3 apoptotic protein in the colony cage group was significantly lower than that in the single cage group and the large cage group(P < 0.05),and the total optical density of Bcl-2 anti-apoptotic protein in the colony cage group was significantly higher than that in the single cage group and the large cage group(P < 0.05),respectively.(6)The results of sperm apoptosis determination in sexual maturity period showed that: at the age of 25 and 30 weeks,the three groups had the lowest sperm death rate and the highest total sperm apoptosis rate.There were no significant differences in sperm mortality,early apoptotic rate,late apoptotic rate and total apoptotic rate among the three groups(P > 0.05),and there were no significant differences in the expression of apoptotic genes Caspase-3,Caspase-8,P53,Bcl-2 and Bcl-xl in mature sperm of the three groups(P > 0.05).In conclusion,compared with the males raised in single cage,the cocks reared in natural mating system have better semen quality,especially in semen volume,density,and viability;females stimulates males to secrete more reproductive hormones,and further reduced males' spermatocyte apoptosis,which are helpful to increase the sperm density of males raised in natural mating system.The activity area did not affect males' semen quality. |
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