Effect of supplementation of BSA on in vitro maturation and fertilization of Black Bengal goat oocytes

Abstract

The present study was conducted to find out the effect of bovine serum albumin (BSA) supplementation on in vitro maturation and fertilization of Black Bengal goat oocytes. Goat ovaries were collected from municipal slaughterhouse and cumulus oocyte complexes (COCs) were collected by aspiration technique. Collected COCs were matured in TCM-199 medium supplemented with different levels of BSA as 0% (control), 2.5%, 5.0% and 7.5%. Three levels of cumulus cell expansion after 27 h of in vitro maturation (at 38.5 °C and 5% CO2 in an incubator) observed under microscope and the different stages of nuclear maturation observed based on chromosomal configuration under emersion oil at high magnification. After maturation, fresh buck semen with a concentration of 1×106 sperms mL−1 was used for in vitro fertilization for 5 h at 38.5 °C and 5% CO2 in an incubator. The fertility level was measured based on pronuclei formation. From this study, highest expansion was found in 7.5% BSA supplementation (75.55%), followed by 5% BSA (73.87%), 2.5% BSA (61.68%) and 0% BSA (45.36%). The percentages of COCs matured up to metaphase-II stage were 40.78, 57.74, 67.52 and 68.95 at 0% (control), 2.5%, 5% and 7.5% level of BSA, respectively. It was also observed that significantly (p<0.01) higher percentage (35.52% and 37.74%) of normal fertilization (formation of 2 pronuclei) was observed in 5.0% and 7.5% BSA level compared to control (23.28%) and 2.5% level (29.30%). These results indicated that the cumulus cell expansion, nuclear maturation and fertilization rate could be significantly increased (p<0.01) by supplementing 2.5% level of BSA. The rates could be improved further (p<0.01) by increasing the level up to 5% but no more improvement (p>0.05) occurred when BSA was increased to 7.5%. Thus, it can be concluded that bovine serum albumin at 5% level might be used as a supplement for maturation and fertilization of goat oocytes in TCM-199 medium.