IGF Genes in Golden Pompano Trachinotus ovatus Larvae

Insulin-like growth factors (IGFs) include IGF I and IGF II. IGF I is an essential regulator of cell division, differentiation, embryonic development, and growth. IGF II, also known as somatomedin A, is mainly involved in the regulation of embryonic growth. Growth hormone may have different effects on IGF-II gene expression in different fish. This chapter reviews some studies on IGFs in fish larva and juvenile, analyzes the expressions of IGF I and IGF II at different time of ontogenesis and incubation temperature, and evaluates the effects of nutrition on IGF expression in Trachinotus ovatus larvae and juveniles. The expression of IGF I increased with the growth of larvae and juveniles, but the influence of water temperature was not significant. The water temperature influences the expression of IGF II. Its expression at 23 °C was significantly higher than that at 26 and 29 °C. The expression of IGFs in fish larvae on 28 DPH was not accompanied by nutrient manipulation. The time-dependent expression of IGF genes of larval fish is crucial to understand the ontogenetic development and larval fish growth in early life.