Effects of short‐term temperature changes on the physiology, biochemistry and feeding behaviour of the juvenile yellow seahorse— Hippopotamus kuda Bleeker

Abstract

In order to study the impact of acute temperature challenge on juvenile hippocampus's growth, the variations of external behavioural indexes and internal physiological, biochemical and genetic indexes were analysed at the same time under acute temperature change. In this paper, the external indexes we selected were the response parameters of feeding behaviour (including feeding reaction time, feeding rate and food intake, etc.). The internal indicators include biochemical indicators (SOD, CAT, AKP, ACP, Trypsin, LPS and AMS enzyme activity and MDA content) and fold change (differentially expression multiples) of differentially expressed gene (Hsp70, Hsp90, Gst, Pyy, mTOR, Bcl-2, Casp9, Casp3, Gadd45α, Fadsd6, Cpt1, Fas, Cyp51, Pdha1, Mdh1, Idh3b and G6pd). The results showed that the juvenile's external indexes had changed significantly at 12 h after short-term temperature challenge exposed. At the same time, the feeding reaction time (s) was extend, and the feeding rate (individuals/min) and food intake (individual) were reduced, suggesting that the growth of juvenile might be suppressed by temperature challenge. At the same time, MDA and AMS showed a significant correlation with the feeding behaviour parameters, and several function genes Gadd45α, Casp3, Idh3b and G6pd also showed a correlation with the behavioural parameters. Our study provide a valuable information for understanding the mechanism of internal and external reaction in juvenile seahorse, which exposed to short-term temperature challenge. It is useful to explore the mechanism of how temperature affects fish growth. And the external behavioural indexes can correctly reflect the excessive fluctuation of environmental temperature that is harmful to the juvenile.