Goat in vitro follicular response to insulin concentration is affected by base medium and follicular stage

Different culture media are used for the culture of preantral (PFs) and antral (AFs) follicles, among them the alpha MEM and TCM199. Also, culture media supplementation with insulin may improve the in vitro development of goat PFs and AFs. However, there is no information on the indicated concentration of insulin and which basis culture medium is the most suitable for caprine PFs and AFs. This study aimed to assess if the culture of PFs and AFs can be affected by the basis medium, and if its supplementation with two different insulin concentrations will improve follicular growth and oocyte development. Isolated PFs and AFs were in vitro cultured for 18 days in alpha MEM, or TCM199 supplemented either with 10 ng/mL or 10 mu g/mL insulin. A higher degeneration rate (P < 0.05) of PFs was observed for TCM199 compared to alpha MEM within the same insulin concentrations. Preantral follicles cultured in alpha MEM with insulin 10 mu g/mL presented the greatest (P < 0.05) daily growth, as well as increased (P < 0.05) antrum formation, while the daily growth rate of AFs was highest (P < 0.05) in alpha MEM supplemented with insulin at both tested concentrations. Furthermore, the development of oocytes recovered from PFs and AFs was improved when culture was performed in alpha MEM supplemented with insulin 10 ng/mL.