Effects of dietary curcumin supplementation on seminal quality indices and fertility rate in broiler breeder roosters.

1. Decreased semen quality is an underlying contributor to age-related subfertility in broiler breeder roosters. This study investigated the effects of dietary curcumin (derived from turmeric) supplementation as an antioxidant source on semen quality and fertility in broiler breeder roosters. 2. Twenty-eight Ross 308 roosters were randomly allotted to four groups with seven birds in each and were fed a standard diet supplemented with different levels of curcumin at 0 (C0), 10 (C10), 20 (C20) and 30 (C30) mg/bird per day from 48 through to 61 weeks of age. Body weight and semen quality traits were evaluated on a weekly basis and seminal concentrations of malondialdehyde (MDA) as a measure of antioxidation status were quantified at one-week intervals during the first 11 weeks of the trial (48-59 weeks of age). Semen samples from last 2 weeks (60 and 61 weeks of age) were used to artificially inseminate to assess the sperm-egg penetration (SP) in perivitelline membrane and fertility rates. 3. Except for body weight and ejaculate volume, other characteristics, including semen concentration, total sperm production, progressive motility and plasma membrane integrity were linearly improved by the increasing levels of curcumin supplementation (P < 0.01). However, dietary curcumin levels were linearly and quadratically associated with decreased seminal concentration of MDA (P < 0.01 and P < 0.03), percentage of abnormal sperm (P < 0.01 and P < 0.07) and increased plasma membrane functionality (P < 0.01 and P < 0.04), respectively. The SP holes in perivitelline membrane were increased in a linear and quadratic manner in response to increasing levels of curcumin (P < 0.01). Moreover, fertility rate was linearly improved (P < 0.01) as the dosage of curcumin increased, and resulted in 8, 12 and 14% improvements in the birds fed C10, C20 and C30, compared to C0, respectively. 4. In conclusion, the results showed that increasing levels of dietary supplementation of curcumin was associated with beneficial effects on semen quality indices and fertility rate in aged broiler breeder roosters.