Characterization of ghrelin mRNA expression in fasting Larimichthys crocea juveniles

Larimichthys crocea is a marine fish species cultured in China. Short-term starvation is often applied to improve the quality of cultured L. crocea, and the expression of ghrelin in tissues of stomach, muscle, brain, intestines, liver, and kidney, involved in starvation response, under starvation conditions were studied to understand the effect of starvation on the expression of ghrelin in L. crocea juveniles. The ghrelin expression was tissue-specific, and expression was significantly higher in the stomach compared to other tissues (P<0.01). Additionally, ghrelin expression in different tissues changed along with prolongation of fasting. In the stomach, ghrelin expression levels increased gradually at the beginning of the fast, and then declined after eight days of fasting. Gene expression in the brain and intestines increased at the beginning of the fast, and then decreased with longer fasting time. Interestingly, ghrelin expression declined at the beginning of the fast, then increased with longer fasting in the kidneys and muscles. These results suggest that ghrelin is involved in starvation response in L. crocea juveniles. This study provids insights into ghrelin function and an important reference for the development of reasonable feeding strategies for L. crocea juveniles.