Serum kisspeptin: New possible biomarker for sexual behaviour and sperm concentration in buffalo bulls.

The study was designed to decipher the inter-relationship between peripheral hormones (kisspeptin and testosterone), sexual behaviour and seminal variables of Murrah buffalo bulls (n = 134). In this study, we recorded that 13%, 37%, 40%, 6% and 4% Murrah buffalo bulls had reaction time of <30, 31-60, 61-180, 181-300 and >300 s, respectively. Further, it was observed that 4%, 85% and 10% buffalo bulls were sexually aggressive, active and dull, respectively, during semen collection. The courtship behaviour was not found to be desirable for the bulls used for the semen collection. Mean of ejaculate volume, sperm concentration and mass motility (0-5 scale) were 3.57 ml, 977.11 million/ml, 2.7, respectively. Correlation studies revealed that the reaction time was positively correlated with courtship behaviour and body weight, and negatively correlated with sexual aggressiveness and sperm concentration. Serum kisspeptin in buffalo bulls, measured for the first time, was found to 3.8 ± 0.7 ng/ml. Serum kisspeptin and testosterone level are negatively correlated to each other and kisspeptin level influenced the sexual behaviour (reaction time, sexual aggressiveness and penile erection) of study bulls. Serum kisspeptin was higher in the buffalo bulls with higher sperm concentration indicating its role in spermatogenesis. In conclusion, for the first time basic information related to sexual behaviour of Murrah buffalo bulls in large population along with its inter-relationship with peripheral hormones (kisspeptin and testosterone) has been documented.

Sodium alginate potentiates antioxidants, cryoprotection and antibacterial activities of egg yolk extender during semen cryopreservation in buffalo.

The study was conducted to determine effects of sodium alginate on sperm during cryopreservation. Each ejaculate (n = 20) of five buffalo bulls (3-5 years) were divided into six equal fractions and diluted using egg yolk based extender supplemented with different concentrations of sodium alginate and cryopreserved. Frozen-thawed semen samples were evaluated using the CASA, hypo-osmotic swelling test, cervical mucus penetration capacity test, and chlortetracycline fluorescence assay (CTC). Phosphorylation of tyrosine containing proteins and malondialdehyde concentration of sperm membrane were evaluated using immunoblotting and thiobarbituric acid reactive substance assay respectively. The semen extender's anioxidative capacities were estimated by conducting 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays, metal chelating capacity by assessing ferrozine and antibacterial capacity using agar plate methods. Supplementation of sodium alginate in extender improved sperm longevity, plasma membrane integrity as well as capacity to transit through the cervical mucus. Supplementation of extender with sodium alginate minimises the phase transition of sperm membranes and phosphorylation of tyrosine containing proteins during cryopreservation. Malondialdehyde concentration of sperm was less in sodium alginate-treated sperm as compared with control samples. The results indicated that sodium alginate increased antioxidant capacity of semen extender. Supplementation with sodium alginate also improved the metal chelating capacity and antibacterial properties of the extender. In conclusion, supplementation of extender with sodium alginate enhances free radical scavenging, metal reduction and chelating capacities to protect sperm during cryopreservation.