Feed Restriction and IGF‐1 Affect the Oocyte Maturation in Matrinxã Brycon amazonicus

Abstract

The feeding and nutrition of breeders are crucial aspects in the reproductive process. During the maturation period, metabolic changes occur aiming at mobilizing energy for growth and follicular development. The involvement of IGF‐1 in metabolic and reproductive events is important. The aim of this work was to evaluate if alternate feed restriction and re‐feeding have permissive effects on in vitro actions of IGF‐1 on oocytes development of matrinxã. In vivo experiments were performed during vitellogenesis period. Females (n = 60) were fed with a commercial feed (2% of biomass) and they were divided into two treatments: fish receiving food daily (control ‐ fed), and fish submitted to cycles of three days of feed restriction and two days of re‐feeding (no fed group). The ovaries removed at the end of in vivo experiment were maintained in phosphate‐buffered saline (PBS) and the oocytes were mechanically dissected. The collected oocytes (n = 20) were cultured in 24 well plates (20 oocytes/well/mL) in Leibowitz medium supplemented with 20nM HEPES, antibiotics (1000U/mL penicillin and 100 μg/mL streptomycin) and 0,1% bovine serum albumin (BSA), in a final volume of 1,0mL, pH 7,5. The oocytes were divided into four treatments: a) fed ‐ IGF‐1; b) fed + IGF‐1 (0; 1; 10 and 50nM); c) no fed ‐ IGF‐1; d) no fed + IGF‐1 (0; 1; 10 and 50nM). The assays were performed in triplicate and the plates were incubated at 26° C for 3 hours. Fish under restriction had lower body weight, decreased plasma glucose, increased triglycerides levels, and their final maturation and mature oocyte were reduced and the atresic ones were in higher number. Moreover, the IGF‐1, in vitro, increased the percentage of mature oocytes in fed females and decreased the atresic ones. In no fed females, IGF‐1 increased the final maturation and mature oocytes and reduced the atresic ones. This study demonstrates the importance of the feeding management of female breeders of matrinxã during the vitellogenesis period. The feeding management affects oocyte development, food restriction impairs and IGF‐1 restores the negative effects on oocyte development induced by feeding management.Support or Funding InformationCNPq