THE EFFECT OF FETAL CALF SERUM CONCENTRATIONS UPON THE In Vitro Bos taurus indicus X Bos taurus taurus CROSSBRED EMBRYO PRODUCTION AND THE CYTOPLASMIC LIPID ACCUMULATION

Abstract

The aim was to test the supplementation of five different concentrations of fetal calf serum (FCS) upon the in vitro production (IVP) and cytoplasmic lipid accumulation in Nelore and Simmental crossbred bovine embryos. The addition of serum started on D3 of embryo culture. Nelore oocytes were submitted to in vitro maturation, in vitro fertilization with Simmental semen, and in vitro cultured. From D1 to D3 it was used the SOFaa media + 0.5% BSA without serum (Base Media). From D4 to D7 the embryos were divided into four experimental groups according to the concentration of serum that was added to the Base media: Group 0-0%:  without serum; Group 0 – 2.5%: 2.5% of serum; Group 0-5%: 5% of serum; and Group 0-10%: 10% of serum. As for the Control group it was used Base Media + 2.5% of serum from D1 to D7. Statistical analysis was done with ANOVA followed by the Tukey test (P0.05) when assessing cleavage (72.74±3.18%, 84.18±0.74%, 68.46±2.35%, 75.72±1.77%, 81.07±3.38%), blastocyst formation (32.62±0.59%, 27.27±0.93%, 27.04±2.25%, 30.31±1.31%, 37.13±1.50%), development stage (5.16±1.12, 5.01±1.10, 5.06±1.02, 4.98±0.99, 5.21±1.04) and embryo quality (2.80±1.39, 2.89±1.36, 2.99±1.33, 2.78±1.42, 2.65±1.39), for the groups Control, 0-0%, 0-2.5%, 0-5% e 0-10%, respectively. However, the increase of serum concentration in the embryo culture media showed an increase of medium and large, lipid droplets. Nevertheless, for the groups with lower concentrations of serum (0-0% e 0-2.5%) the number of small lipid droplets was similar to the ones with higher concentrations (0-5% e 0-10%). We can conclude that it is possible to perform the IVP with no supplementation of serum in culture media, without producing any negative effect upon the production, development, and embryo quality.