Effect of sperm concentration and condition of in vitro maturation and fertilization of oocytes of under heat stress bovine on polyspermy in derived zygotes

Authors
Azizollah Bakhtari
Hamid Reza Rahmani
Abstract
Infertility due to heat stress is one of the great economic problems in dairy industry. Heat stress at the earliest stages of follicular growth can affect the oocyte quality and developmental competence. The objective of this study was to determine factors which may have role to reduce of polyspermy in heat stress condition. For this propose, some changes in sperm concentration, maturation medium, and fertilization medium were done. In first step, three concentrations of sperm (0.5×106, 0.75×106 and 1×106) were selected. Results showed that with decrease in sperm concentration, polysermic rate did not significantly changed (p>0.05). But in 0.5×106 sperm concentration, fertilization rate significantly decreased (p0.05). In the next step, adding two different levels of heparin (1 or 10 µg/ml) in fertilization medium was evaluated. The fertilization parameters did not affected by both concentrations of heparin (p>0.05). In last experiment, non-essential amino acid was removed from fertilization medium. Polyspermic rate was reduced to less than 15% in non-amino acid group. The cleavage, blastocyst, hatched blastocyst rates significantly promote in group without amino acid (p
Keywords
Heat stress-Fertilization medium-Non-essential amino acids-Blastocyst-Polyspermy-
Iranian Journal of Veterinary Clinical Sciences
Volume 7, Issue 2
October 2013