Reducing Endogenous Estrogen in Aging Broiler Breeder Male Does Not Affect Fertility And Libido

Libido and sperm fertilizing ability are main criteria for fertility and treatments to increase sperm production capacity should be compromised with either libido or sperm quality.Manipulations to increase fertility in domestic animals will only be useful if libido and sperm fertilizing capacity are not adversely affected. The present experiment was designed to evaluate the effects of reducing endogenous estrogen on libido and in vivo fertility in aging male broiler breeder. Twenty roosters divided into two groups (control and treated with an aromatase inhibitor, letrozole (0.03mg/kg/day)) and they were raised under the same management conditions in an environmentally controlled facility (22°C and a 16L: 8D photoschedule) and fed a corn-soybean based diet (NRC, 1994). Roosters were orally treated daily for 14 consecutive weeks, to reduce testicular estrogen production. Least-square means were computed and tested for differences by the Duncan test (considering P < 0.05 as significant). Letrozole treatment significantlydecreased in vivo fertility and libido compared to control group (P> 0.05). In conclusion, reduction of endogenous estrogen had deleterious effects on roosters libido and in vivo sperm fertilizing ability. Although 14 weeks treatment with letrozole showed a deleterious effects on fertility, but its effect for short-term or interval treatment isrequired to be evaluated within the testes. The relationship between reprogrammed aromatase activity and maintenance of increased fertility needs to be examined in future experiments.

Keywords:

Fertility , Aromatase , Rooster , Libido , Aging