Male fertility in poultry industry is one ofthe most important traits which dictate ultimate profitability. Recycling is though typically laying hens’ phenomenon, however, a few attempts in the past gave the hopeof augmenting the avian male fertility.
Therefore, a project was designed to recycle the culled male broiler breeders through zinc-induced molting. After molt, the birds were supplemented with some feed additives or reduced the protein level in feed as a part of two prong strategy to increase broiler breeder’s male fertility. According to the project design, male broiler breeders (Hubbard) at the age of 65 weeks were subjected to zinc-induced molting after 7 days adaptation period. Upon completion of molting, birds were randomly assigned to 6 groups. One group served as a control while the other groups were fed vitamin E, C, probiotics, less than normal level of protein or combination of these components. After first semen ejaculate, sampling was conducted and continued for the next 5 weeks.
The results obtained revealed that overall body weight did not differ between the groups, however, among the body organs weight, liver and heart weight increased significantly in combination group. Testes weight increased significantly in vitamin E fed groups, while pituitary weight increased significantly in vitamin E and C groups. Among the semen traits, semen volume did not differ between the groups, however, overall mean semen volume increasedsignificantly in vitamin E and C groups.
Similarly, sperm motility increased significantly in vitamin E group only. Sperm concentration did not change significantly,while dead sperm percentage decreased significantly in vitamin C group. Consequently, increased hatchability was noticed in the vitamin E and C fed groups.
Analyses of serum biochemistry revealed that despite transient TAC fluctuation in vitamin C, protein and probiotics groups, more stable increase was noticed in vitamin E group throughout the period, resultantly overall mean TAC also increased significantly in this group. Opposite to the serum TAC concentration, TOS concentration decreased in the treated groups, however, sharp decline was observed in the vitamin E group. Compare to control group, serum homocysteine concentration decreased significantly in vitamin E group.
Among serum enzymes, paraoxonase and arylesterase concentration increased significantly in vitamin E and C groups. Mean serum ceruloplasmin decreased significantly in vitamin C and combination groups. Overall mean serum ALT and AST decreased significantly in vitamin E group. Among the semen biomarkers, TAC concentration remained stable up to the week of the experiment, however, overall mean TAC increased significantly in vitamin E group. Similarly, seminal plasma homocysteine concentration decreased significantly in vitamin E and C groups. Seminal plasma enzymes including paraoxonase, arylesterase and ceruloplasmin showed increasing trend in combination group. However, seminal plasma ALT and AST concentration decreased significantly in vitamin E fed group.
Results of serum hormones including T3, T4and cortisol concentration revealed that vitamin E fed group registered significantly highestconcentration of thyroid hormones. On the other hand, cortisol concentration did not differ atdifferent weeks and on overall basis.
Among parameters of cell mediatedimmunity, macrophage engulfment percentages did not differ among the treatmentsboth at 60 and 90 minutes at any week of the experiment. Overall mean engulfment percentage, opsonized and unopsonized, at 60 and 90 minutes, increased significantly in vitamin E fed groups. Similarly, macrophage nitric oxide production did not differ at 60 and 90 minutes in both conditions of opsonized and unopsonized. Like macrophage engulfment percentages, overall mean nitric oxide production increasedsignificantly in vitamin E supplemented group. In the current study, we tested serum antibody titer against ND and IB and the results indicated that the ND titer was higher in vitamin E and C groups, while titer against IBD was elevated in vitamin E fed group. The immunohistochemical study indicated that FSH, LH gonadotrophs cell size, cell area, nucleus size and nucleus area increased significantly as a result of vitamin E supplementation. No significant difference was found in somatotrophs cell size, cell area, nucleus size and nucleus area. The present study also showed that lactotrophs cell size, cell area, nucleus size and nucleus area increased in vitamin E supplemented group.
We further investigate the effect of molting and subsequent treatments on the status of serum and seminal plasma electrolytes, macr- and microminerals. The results revealed that serum and seminal plasma electrolytes did not differ between the groups in post-molt treated groups. In macrominerals, serum and seminal plasma, overall mean Mg concentration increased significantly in vitamin E fed group. Serum microminerals including Fe, Cu and Mn did not differ between the groups, however, overall serum Zn concentration increased significantly in vitamin E fed group. In seminal plasma, Fe, Zn and Mn did not differ, however, seminal plasma Cu concentration improved significantly in vitamin E fed group.
The fertility of male broiler breeders is going to be reduced particularly after 50 weeks of age. At the age of 65 weeks, their fertilizing ability is reached to diminishing level and such birds are culled due to pooreconomic outcome. Unlike laying hens, male birds are usually not recycled. In this study, we attempted to recycle male broiler birds through zinc-induced molting and supplemented them with different feed additives, the fruitful effects of which are well documented. We did not find any significant effect of protein, probiotics in this study. The cumulative effect of vitamin E, C, probiotics and protein was notas good as individual effect of vitamin E. In this study, we found that vitamin E improved semen quality traits and increased the hatchability. Similarly, we also observed that serum and seminal oxidative stress was reduced and the respective antioxidant enzymes status was improved in both the medium. As a positive effect of vitamin E, the immune level of the birds was improved and certain important minerals like Mg, Zn and Cu concentration were elevated. Additionally, the Immunohistochemistry of FSH and LH gonadotrophs and lactotrophs morphometry improved as a result of vitamin E supplementation which may be responsible for efficient secretion of these hormones. In conclusion, these data suggested that vitamin E is more beneficial in improving the reproductive performance of male broiler breeders after zinc-induced molting.
Source: Rifat Ullah , Khan (2012) Effect Of Protein, Probiotics, Vitamins C And E On Semen Quality, Biochemical And Immunological Profiles Of Aged Broiler Breeders After Molting. PhD thesis, University of Agriculture, Faisalabad .