Age–related rump fat, fat percent, body fat mass, leptin, androgens and semen parameters of Arab stallions

Abstract

Objective: To study the effect of age and body fat on leptin levels and semen parameters of Arab horse. Methods: Fifteen fertile Arab stallions of different ages belonging to Police Academy were divided into three equal groups according to their age. Old horses are those of >18 yeas (18–27), Mid-age horses ≥13 to 18 years (13–18), Young horses are those of <12 years (7–11). Semen was evaluated three times for each stallion. Blood and seminal plasma were assayed for measuring leptin, testosterone and estradiol. Subcutaneous rump fat thickness was measured using ultrasound for estimating body fat percent and fat mass percent. Results: All body fat parameters were significantly high in Young stallions and decreased with increasing age. As age increased, testosterone levels increases but leptin levels decreased. Age was inversely correlated with fat %, fat mass and leptin. All fat parameters had direct correlation with leptin in semen and serum but an inverse one with serum testosterone. Serum leptin directly correlated with sperm cell concentration in Mid-age stallions and inversely correlated with percent of live sperm in Old stallions. Semen leptin correlated directly with both percent of live sperm and percent of abnormal sperm in Old stallions. Conclusion: This study proved that aging in stallions is related to a drop in fertility, a decrease in body fat and in turn leptin. Arab stallions of age 7 to 18 years could be used in the breeding efficiently.

Keywords

• Stallions
• Rump fat
• Semen
• Leptin
• Androgens
• Age