Innovative strategies to improve fertility of buffalo semen

Abstract

The improvement of fertility is an important contribution that applied scientific research can provide to buffalo breeding, especially in productive areas like the Campania region. Many studies have been conducted to improve the management of the female reproductive system, while insufficient are the information about the effect of the male on the reproductive efficiency in this species. Buffalo is a photoperiodic animal that tends to increase the reproductive activity during periods when daylight hours decrease. In particular, in the male, it is manifested by a reduction of libido when daylight hours increase. This causes a reduction in the number of jumps and a worsening of the qualitative characteristics of the semen produced . Also, the cryopreservation process influences the quality of the semen causing premature sperm capacitation hence, reducing its longevity in the female reproductive tract. At present, for cryopreservation of semen, standard protocols are used equally for all species, not considering the significant interspecific differences that exist. The aim of the research was, therefore, to evaluate the effect of season on buffalo frozen-thawed semen and to improve its quality by analyzing the effects of the addition of antioxidants such as resveratrol at various concentrations (0.5, 1, 10 and 50 uM), carnitine (2.5 and 7.5 mM ) and sterols, such as cholesterol (1.5 and 3 mg /ml), to the standard freezing extenders. The addition of antioxidants and / or sterol has stabilized the sperm membrane, reducing the state of capacitation, improving motility and consequently semen quality. The effect of the photoperiod was evident with a better semen quality during autumn. Based on these results was also evaluated fertilizing capacity both in vivo (resveratrol and cholesterol) and in vitro (resveratrol and carnitine)selecting concentrations that showed a more marked effect on the stabilization of the sperm membrane. The results obtained suggest that the premature capacitation after cryopreservation of spermatozoa is reduced during the favorable season and that the addition of antioxidants and / or sterols has a positive effect on buffalo semen quality and consequently, on in vitro and in vivo fertility.