Sperm selection techniques and antioxidant fortification in low grade semen of bulls: Review

Abstract

The low grade ejaculates are very common in bulls. Low grade ejaculates might be due to age or non specific factors like thermal stress, transport and vaccination stress during the dynamic life of bulls. Lipid peroxidation of membrane induced sperm damage further aggravates the situation. Researches reveal that selection of sperm and antioxidant fortification play crucial role in improving the quality of semen. Different methods used for semen up-gradation like washing, sedimentation, swim up procedure and filtration like percoll gradient, glass wool, sephadex and sephadex ion exchanger with significant improvement in motility, Hypo osmotic swelling test reactivity, viability and acrosomal integrity. Antioxidants are added directly to extender at standard dose rate with positive result. Among different filtration column used sephadex ion exchanger (FS+IE) was superior over other in improving the semen quality especially when fortified with Vitamin E. Moreover a complete protocol is required, which contain both antioxidant fortification and sperm selection simultaneously to handle the low grade semen from sub-fertile bulls.