Testis development and gonadotropin secretion in broiler breeder males

One-day-old chicks were used to evaluate testis development and concentrations of luteinizing hormone, follicle-stimulating hormone (FSH), and testosterone during ontogenesis. Males on a conventional breeder program (control) were reared on a 15L:9D photoperiod and ad libitum food and water intake for 2 wk. On the third week, males were placed on a restricted diet and the photoperiod was reduced to 8L:16D. Males on a pedigree breeder program (broilerized) were reared on a 23L:1D photoperiod and unrestricted food and water intake for 6 wk. At 7 wk, males were placed on a restricted diet and the photoperiod was reduced to 8L:16D. On wk 18, both treatment groups were photostimulated (16L:8D) until the end of the experiment (50 wk). After photostimulation, there was an exponential increase in testis weight (TW), FSH, and testosterone concentrations. At 28 wk, TW from broilerized males were significantly heavier than those from control birds, and concentrations of luteinizing hormone, FSH, and testosterone were maximal at that time. After 28 wk, there was a significant decrease in FSH and testosterone concentrations that were associated with reduced TW. No correlation was observed between BW and TW. However, TW was highly correlated with FSH concentrations and daily sperm production. Our data suggest that management and photoperiod had a profound effect on testicular function that was associated with FSH concentrations in male broiler breeders.