Nutrition is a strong environmental factor which affects animals productivity in terms both reproductive capacity and production traits. It is therefore imperative to ensure optimal environmental conditions before animals productivity is assessed. The present study was set up to investigate the reproductive capacity of the Nigerian local turkey toms, under different crude protein influences.
A group of Nigerian local turkeys (n = 24), Fifteen toms and nine hens were used in the study. The females were placed on commercial layer mash, 16% crude protein (CP), while the males were grouped into three, five per group, and placed on varying levels of protein, 12% CP, 16% CP and 20% CP for groups 1, 2 and 3 respectively. Semen samples were collected and analysed twice weekly for thirteen weeks. This began after they had been acclimatized for the initial three weeks. Ejaculate volume, semen concentration, semen PH, gross and individual motilities, live and dead sperm and sperm morphology were investigated and recorded. The semen was used to inseminate hens (100 x106 spermatozoa/week/hen) whose eggs were collected to test for the fertilizing ability of the sperm cells in vivo on group basis. The semen was further used to perform an in vitro assay to test the fertilizing ability of spermatozoa on individual basis. Data were summarized as mean ± SEM (Standard Error of the Mean).
The toms in groups 3 had significantly (P < 0.05) higher ejaculate volume 0.29 ± 0.03 mls and semen concentration7.766 ± 0.612 x109 than groups 1 and 2. There was no significant (P > 0.05) difference between groups 2 and 3 in values of gross motility, individual motility, live sperm count and total sperm defects, the two group however, had significantly (P < 0.05) higher values for the parameters than group 1. The fertilizing abiblity, which was assessed through in vivo and in vitro sperm penetration assays revealed significantly higher number of sperm penetration holes (P < 0.05) in Groups 2 and 3, 160.97 ± 8.084 and 172.83 ± 7.647 (in vivo); 187.96 ± 8.121 and 189.16 ± 6.446 (in vitro) respectively, than in group1. Semen production trend was found to be similar between the groups through the thirteen weeks of study.
From these results, the local turkey toms could parallel their exotic counterpart under optimum environment, without the need for genetic hybridization. 20% CP had more positive influence on the semen quality and fertilizing ability of indigenous Nigerian turkey toms followed by 16% CP with 12% CP exerting the least positive influence. Further work was recommended to determine optimal level of other feed components for the breed. Adoption of 16-20% CP is recommended for the Nigerian local turkey toms pending the determination of the optimal level of other components.
Key words: Artificial Insemination, Crude protein, Reproduction, Semen, Turkey toms
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