| Zinc,manganese,copper,iron and selenium serving as trace minerals,were well known to be nutritionally essential for roosters reproduction.In order to obtain the maximum growth rate,dietary inorganic trace minerals were much higher than those recommended by NRC for poultry.However,there was less research on the effect of organic mineral on poultry semen quality and the development of testis.In the present studies,Xue Shan and San Huang roosters were used to detect the effect of different forms and concentrations of complex organic trace minerals on semen quality,the histological structure,the ultrastructure of testis and sperm,serum testosterone concentration and the related-genes mRNA expression of testosterone synthesis in rooster.It could provide a scientific basis for comprehensive assess of the beneficial effects of complex organic trace minerals to improve fertility.1.Effect of dietary complex organic trace minerals on semen quality and testis in breeder roostersOne hundred and ninety-two 23-week-old Xue Shan roosters were randomly divided into two groups:inorganic trace minerals group(Inorg-TM)and organic trace minerals group(Org-TM).According to the NRC(1994)recommended chicken requirements,Inorg-TM were added with 100%level of NRC recommended inorganic trace minerals included Mn,Zn,Fe,Cu,Se.Org-TM were added with 80%level of NRC recommended from the form of 40%inorganic trace minerals plus 60%the organic.Each group repeated six times and every repeat included 16 roosters.One rooster was randomly selected from each replicate for semen collection.The first time of semen collection was taken after 1-week treatment(1W),and the other 19 times was taken by 2-week internal.After 39-weeks treatment,these 12 roosters were slaughtered for collecting serum and testes.The results showed that the concentration of zinc in organic fodder was significantly decreased than the inorganic(P<0.05).Semen quality was improved significantly in Org-TM compared with Inorg-TM.Semen volume was increased in Org-TM from 8W to 22W,compared with Inorg-TM(P<0.01).There was an higher increase in sperm density(P<0.05)than those in Inorg-TM from 8W to 12W.Abnormal morphology was decreased in Org-TM than Inorg-TM from 14W to 22W(P<0.05).There was no significantly differences in body weight and testes' relative organ weight between two groups.Histological observation showed that complex Org-TM could relieve the shedding of spermatogonium and Leyding cells compared with Inorg-TM.Ultrastructure observation showed that both mitochondria vacuolation in spermatogonium and pyknosis of nucleolus were more in Inorg-TM than those in Org-TM.In Inorg-TM,there were more lost acrosome,condensed mitochondria and damaged plasma membrane than Org-TM.In summary,our results showed that in this supplemented level of 80%level of chicken requirements from the form of 40%inorganic trace minerals plus 60%the organic,it could improve semen quality and promote the testis development.2.Effect of dietary complex organic trace minerals on testosterone synthesis and the related gene expression in breeder roostersIn order to clarify the mechanism underlying the positive effect of organic trace minerals on semen quality in roosters,two hundred and forty 23-weeks-old San Huang roosters were randomly divided into two groups:inorganic trace minerals group(Inorg-TM)and organic trace minerals group(Org-TM).According to the NRC(1994)recommended chicken requirements,Inorg-TM were added with 100%level of NRC recommended inorganic trace minerals included Mn,Zn,Fe,Cu,Se.And then,Org-TM were added with 100%level of NRC recommended organic trace minerals.Every group repeated six times and every repeat includes 20 roosters.The experiment period was 22 weeks.One rooster was randomly selected from each replicate for semen collection.The first time of semen collection was taken after 2-week treatment(2W),and the other 10 times was taken by 2-week internal.Another one rooster was randomly selected from each replicate for slaughter at 3 time points(7W,12W,22 W).The results showed that the concentration of znic and manganese in organic fodder was decreased significantly than the inorganic(P<0.05).Semen volume was increased in Org-TM from 8W to 22W,compared with Inorg-TM(P<0.01).There was an higher increase in sperm density and motility(P<0.05)than those in Inorg-TM from 8W to 12W.Abnormal morphology was decreased in Org-TM than Inorg-TM from 1W to 22W(P<0.05).There was no significantly differences in body weight and testes' relative organ weight between two groups.Histological observation showed that for three times slaughter,complex Org-TM could relieve the shedding of spermatogonium compared with Inorg-TM and Leyding cells were closed packed.Serum testosterone concentration was significantly higher than Inorg-TM in Org-TM when 12W and 22W(P<0.05).The relative mRNA expression of HSD3B2 and CYP17A1 increased significantly at 22W than Inorg-TM(P<0.05).The relative mRNA expression of HSD17B4 increased significantly at 7W and 12W than Inorg-TM,and decreased at 22W(P<0.05).The relative mRNA expression of CYP19A1 was significantly lower than Inorg-TM at 7W,but was higher at 12W and 22W(P<0.01).Hence,our results showed that,in this supplemented level of 100%level of chicken requirements in forms of organic trace minerals,it could improve semen quality and the function might be achieved by promoting the synthesis of testosterone.3.Security evaluation of dietary complex organic trace minerals for promoting semen quality in breeder roostersIn order to determine the security of complex organic trace minerals utilized in rooster diet,the tissue trace concentration and serum antioxidative banlance were messured from rooster in the second experiment.The results showed that there was no significantly difference for five trace minerals' concentrations in serum and testis between two groups and only Fe's was significantly decreased in serum of Org-TM at 7W(P<0.01).At 12W,there were no significant differences.At 22W,the concentration of Zn in testis and Mn in serum were increased significantly than Inorg-TM(P<0.05).Compared with Inorg-TM,at 7W the GSH level was decreased in testis of Org-TM(P<0.05)and the T-SOD activity was higher(P<0.05).At 12W,the GSH level was increased significantly in Org-TM(P<0.05).At 22W,the CAT activity was decreased in Org-TM(P<0.05).In Inorg-TM,the activity of CAT was decreased for three times.These results suggested that,in this supplemented level of 100%level of chicken requirements in forms of organic trace minerals,complex organic trace minerals could withstand oxidative stress by minerals alleviate the oxidative damage.Alternatively,it was safe to supply the complex organic trace minerals in rooster diet to enhance semen quality. |
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