Additional dietary calcium fed to Barred Plymouth Rock roosters reduces blood cholesterol, elevates seminal calcium, and enhances sperm motility, thermo-tolerance and cryosurvivability

Chicken sperm cryosurvivability may be enhanced by manipulating diets fed to roosters because diets modify quality of fresh semen. This study investigated the possibility of added dietary calcium (Ca) improving chicken sperm cryosurvivability due to an elevation in seminal Ca concentration ([Ca2+]) and a reduction in blood cholesterol (Ch), which may increase fresh sperm quality, thus thermo-tolerance and cryosurvivability. Thirty 21-wk-old Barred Plymouth Rock roosters were fed diets containing 0, 2 or 4% added Ca for 26 wk. Blood [Ca2+] and Ch in individual males were assessed weekly. Seminal [Ca2+], Ch and sperm motility at 0, 1, 2 and 3 h after incubation at 41 °C in seminal plasma from males of different groups were evaluated at 28, 29, 30, 31, and 33 wk of age upon pooling the samples per treatment during each collection. Also, sperm motility of fresh pooled semen and of frozen-thawed samples, collected at 34, 35, 36, 37 and 38 wk of age, were analyzed. From 22 wk of age onwards, blood [Ca2+] was significantly higher and Ch lower in treated males than the control. Seminal [Ca2+] in treated males was higher than in the control during the sampling period, with 4% group being highest, followed by 2%, and control groups, but seminal Ch was similar among treatments. Regardless of the seminal plasma source used, motility was superior in males fed 2% added Ca, followed by control, and 4% group. Spermatozoa of males fed 2% added Ca had the highest motility in their own seminal plasma or of control males. Also, spermatozoa of all treatment males displayed higher motility in control seminal plasma compared to that of treated males. Frozen-thawed sperm motility pattern was similar to that of fresh semen; with that of 2% group exhibiting superiority to that of control or 4% added Ca-fed males. Indeed, additional dietary Ca elevated seminal [Ca2+] and lowered blood Ch, which enhanced fresh sperm quality measured as motility, thermo-tolerance and cryosurvivability, especially in 2% group, but not 4% added Ca-fed males.