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The aim of this study was to test the effect of oestradiol-17β (E 2 ) on the motility, viability and the acrosomal status of bull sperm in vitro. Pooled semen from Holstein bulls were incubated in the presence of 2, 4, and 8 μg E 2 /mL for 24 h. Semen was also incubated in media without E 2 . During the incubation, the number of motile, viable sperm and the number of sperm possessing lost/damaged acrosomes, cytoplasmic droplets and coiled tails were counted at 0, 4, 18 and 24 h of incubation. Addition of 2 μg E 2 /mL at 18 h of incubation increased the total motility over the control. The number of forward progressing sperm was increased by the supplementation of 2 and 8 μg E 2 /mL over the control group at the 4 h incubation. Lower doses of E 2 (2 and 4 μg/mL) did not affect viability of sperm, but a high dose of E 2 (8 μg/mL) caused reductions in viability at 4 and 24 h of incubation. The number of sperm cells with lost acrosomes was significantly high in control group at 24 h of incubation. The number of sperm cells possessing proximal and distal cytoplasmic droplets and the number of sperm cells bearing coiled tails were not altered by any of the treatments. A small dose of E 2 (2 μg/mL) had a beneficial effect on the motility and acrosome integrity of bull sperm in vitro. Higher dose of E 2 (8 μg/mL) had a detrimental effect on viability.

The aim of this study was to measure the effect of chicken Gonadotropin Releasing Hormone-I (cGnRH-I) on male fertility potential. Male and female quails were placed in cages(1 male and 5 females) and devoted into four experimental groups: a) control  group - no injection, b) negative control group - 200 μl standard saline was injected, c) 5μg cGnRH group - 5μg cGnRH-I was injected and d) 20μg cGnRH group - 20μg cGnRH-I was injected. Each group was consisting of scattered six cages. In each cage only males were subcutaneously injected under the wing (3 injections - 1 week apart from each other). A fourth injection was administered at the end of egg collection and one hour later blood was collected and serum concentrations of Luteinizing Hormone (LH), Follicle Stimulating Hormone (FSH), prolactin and testosterone were measured. Egg fertility, hatchability and weekly egg production per hen were also measured. Injection of cGnRH-I did not increase pituitary gonadotropin secretion (LH or FSH); however, serum LH concentration non-significantly reduced in negative control group. A significant decrease in serum testosterone concentration was observed in negative control group compared to 20 μg cGnRH injected group. Fertility and hatchability of total set eggs were lower in negative control group compared to other groups. Egg production in control group was significantly decreased, probably due to the non-significant suppression of prolactin. Embryonic mortality (hatchability of fertile eggs) non-significantly increased in control and negative control groups compared to GnRH injected groups. It seems that cGnRH has a positive effect on fertility and hatchability; however, more studies are needed with older males to confirm our findings.