Expression of alpha-amylase and growth-related genes during early larval developmental stages of Clarias magur

To understand the carbohydrate utilization ability during developmental stages of Clarias magur, the mRNA levels and enzyme activity of amylase were studied. Furthermore, the transcript levels of some important growth genes like growth hormone (GH), insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein (IGFBP) were evaluated. The enzymatic activity and mRNA expression of alpha-amylase along with expression of growth-related genes were examined from hatching until 34 days post-hatching (dph) by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Subsequently, mRNA expression pattern revealed the significantly (P <.05) high transcript level of alpha-amylase during early stages and early peaks were found at 3 to 6 dph, later the expression decreased till the end of experiment. Growth-related genes like GH, IGF-I and IGFBP showed a variable level of mRNA expression pattern from 0 dph to 34 dph. However, there was no significant difference (P >.05) in the mRNA expression of growth-related genes among the different time points of the present study. Moreover, the amylase activity revealed almost same pattern as that of its mRNA expression. In general, the present results suggested that C. magur has the ability to utilize the digestible carbohydrates during the early stages and can be helpful in developing low cost feeds for larvae.