ABSTRACT
In bridging the knowledge gap on stress physiology of Nigerian indigenous chickens, this study investigated the effect of exogenous corticosterone (eCORT) as stress inducing agent on the testicular function and mating behavior of Nigerian indigenous cocks. Twenty-four (24) cocks and one hundred and forty four (144) hens (mating ratio of 1 cock: 6 hens) were grouped into four and assigned to each of the four eCORT treatments (0, 2, 4 and 6 mgeCORT/KgBW) daily for 14 days. Semen samples were collected on days 0, 7 and 14 and analyzed for semen volume (SV), progressive sperm motility (PSM), membrane integrity (MI) and sperm abnormality (SA). Mating behaviors were monitored on days 3, 5 and 8. Blood samples, for hormonal (Luteinizing Hormone (LH), Follicle Stimulating Hormone (FSH) Testosterone (TEST) and stress analysis (heterophil/lymphocyte ratio, H/L) were collected from brachial vein on days 7 and 14. On day 15, cocks were euthanized and testes harvested for histomorphometry. Data were analyzed using multivariate analysis, one-way ANOVA and Kruskal-Wallis tests all in SPSS 23. Administration of 4 mgeCORT/KgBW declined (P<0.05) PSM while 4 mgeCORT/KgBW and 6 mgeCORT/KgBW cocks had reduced (P<0.05) SV and MI with increased SA. Compared to baseline values, progressive sperm motility of cocks administered 6 mgeCORT for 7 and 14 days decreased (P<0.05) by 57.5% and 52.4%, respectively. Exogenous CORT had no significant (P>0.05) influence on the mating behaviors, H/L ratio, FSH and TEST. However, 2 mgeCORT/KgBW enhanced LH levels. Administration of eCORT did not affect the testicular epithelial height and seminiferous tubular diameter. In conclusion, optimal stress induced by eCORT impaired semen quality but with less impact on reproductive hormones, H/L and mating behaviors of intensively raised Nigerian indigenous cocks.
ABSTRACT
The current upsurge in intensive farming practices of greater cane rat has not only lead to higher growth rate but is accompanied by increased fat deposition especially in the males. This study attempts to characterize one of the most commonly used fat estimation parameter, the body mass index (BMI) as well as evaluates its relationship with testicular and hormonal parameters in seventy-two sexually active male cane rats over a period of one year. Six animals, kidded and raised in a farm, with known ages were used each month. The experimental protocols entail body measurements of weight, height and length; histology; orchidometry; and hormonal immunoassay of testosterone, estradiol, progesterone, LH and FSH using their various kits. The mean values of the body mass (BMI) and Lee (LI) indices of male greater cane rats were 1.18±0.20g/cm2 and 0.30±0.02g/cm respectively with the testicular histology indicating normal spermatogenesis. BMI/LI, both of which followed the same pattern, neither correlate with testicular parameters nor with serum testosterone, progesterone, LH and FSH concentrations but had low correlations with serum estradiol concentration (r2 = 0. 2; p = 0.0023). So, these relationships may provide clue on obesity and its effect on reproductive performance and strengthened the possibility of the characterized BMI/LI as obesity marker for breeding selection in male cane rat.
