Optimized addition of nitric oxide compounds in semen extender improves post-thaw seminal attributes of Murrah buffaloes.

Semen dilution and cryopreservation alter the homogeneity of seminal plasma, resulting in a non-physiological redox milieu and consequently poor sperm functionality. Considering the concentration-specific bimodal action of nitric oxide (NO) in the regulation of sperm functions, cryopreservation media supplemented with optimized concentrations can improve the semen attributes. The present study aimed to evaluate the effect of adding an optimized concentration of sodium nitroprusside (SNP) and N-nitro-L-arginine methyl ester (L-NAME) in an extender on in vitro semen quality. An aliquot of semen samples (n = 32) from Murrah buffalo bulls (n = 8) was divided into control (C) and treatment (T-I: SNP in extender at 1 µmol/L; T-II: L-NAME in extender at 10 µmol/L). Fresh semen quality parameters showed no significant difference at 0 h except for the structural integrity in the T-II group. Post-thaw semen quality parameters and sperm kinematics using computer-aided sperm analysis (CASA) revealed significantly higher (p < 0.05) cryoresistance in the treatment groups. Viability, acrosome integrity, and membrane integrity were significantly higher (p < 0.05) in both treatment groups; however, the results were pervasive in T-II. Lower abnormal spermatozoa were observed in both T-I and T-II. SNP supplementation led to a significant rise (p < 0.05) in NO, whereas L-NAME reduced the NO concentration in post-thawed samples, which was directly correlated with different sperm functionality and associated biomarkers viz. total antioxidant capacity (TAC) and thiobarbituric acid reactive substance (TBARS). It was concluded that the cryopreservation media supplemented with SNP and L-NAME at 1 µmol/L and 10 µmol/L, respectively, lower the cryo-damage and improve post-thaw seminal attributes.

Effects of monensin feeding on performance, nutrient utilisation and enteric methane production in growing buffalo heifers.

Murrah buffalo heifers (live weight 135 ± 17 kg) were fed a total mixed ration without supplementation (CON), or supplemented with sodium monensin (MON; Rumensin® 200, Elanco Animal Health, Brazil) @ 0.6 mg/kg of body weight for 90 days. Nutrient digestibility and nitrogen retention were estimated during the mid-experiment, and enteric methane production was measured by sulphur hexafluoride tracer technique for consecutive-5 days after the digestion trial. The dry matter (DM) and nutrient intake were not affected but DM intake expressed as percent of body weight was decreased by monensin supplementation (3 vs 2.7% for CON and MON, respectively). The crude protein digestibility was higher for MON whereas, digestibility of other nutrients was not affected. Nitrogen retention (+ 4.59 g/day) and daily body weight gain (+ 56 g/day) were greater for MON-fed heifers without any significant effect on nitrogen intake and nitrogen excretion through faeces and urine. Daily enteric methane production was reduced by 12.61% but the treatments did not differ significantly. Methane emission expressed as gram per unit of DM, organic matter and digestible DM intake was lower for MON than CON and methane conversion rate (Ym) % of GE and ME intake was also decreased by 8-9%. On day 60, blood glucose level was increased and urea nitrogen was decreased in MON-fed heifers. This study indicated that monensin supplementation at 0.6 mg/kg body weight in growing heifers improved daily gain and feed efficiency while it reduced enteric methane production which can reduce feedlot time and consequent life time CH4 production.