Supplemental dietary zinc sulphate and folic acid combination improves testicular volume and haemodynamics, testosterone levels and semen quality in rams under heat stress conditions.

Abstract

This study was aimed to investigate the combined effect of zinc sulphate and folic acid (ZnF) dietary supplementation on testicular haemodynamics (TH), testicular volume (TV), plasma testosterone levels (T) and semen quality of rams under heat stress conditions. Fifteen Ossimi rams were allocated to three groups: (1) G0 (n=5) received only basic diet; (2) G1 (n=5) received basic diet +ZnF (Zn, 0.4mg/kg bw; F, 0.02mg/kg bw) and (3) G2 (n=5) received basic diet +ZnF (Zn, 0.8mg/kg bw; F, 0.04mg/kg bw) daily for 60days. TH was evaluated using colour (testicular coloration, TC) and spectral modes [resistive index (RI) and pulsatility index (PI)] Doppler of the supra-testicular arteries (proximal and distal parts, STA). Semen traits including progressive motility (PM), alive sperm % (AS), sperm viability (SV), sperm abnormalities (SA) and acrosome integrity (AI) were also assessed. The examinations were carried out one month before (D-30), the beginning of ZnF inclusion in the diet (D 0) and continued for the successive two months (D 30 and D 60). TH was significantly (p<.05) improved at D 30 and D 60, evidenced by lowering both RI and PI and increasing of TC in G1 compared to G0 and G2. In addition, both TV and serum T levels were elevated (p<.05) at D 30 and D 60 in G1 compared to other groups. Semen quality parameters (PM, AS, SV and AI) were significantly (p<.05) augmented in the same trend as TH, TV and T in G1 versus G0 and G2. A marked decrease (p<.05) in SA % was noticed at Days 30 and 60 after ZnF inclusion in G1 compared to G0 and G2. In conclusion, supplementation of the summer diet with ZnF improved the whole reproductive functions such as testicular haemodynamics and semen quality of rams housed in heat stress conditions.