Relative expression levels of growth hormone gene and growth rate in Indian major carp species.

The phenomenon of growth is a leading factor for aquaculture success. The uneven growth of major Indian carps (Labeo rohita, Catla catla, and Cirrhinus mrigala) is a serious issue in fish culture from an economic point of view. The growth hormone (GH) gene is crucial for selection in commercially cultivated fish species for better growth and production. Indian major carp (L. rohita, C. catla, and C. mrigala) are commonly cultured in Pakistan. The GH expression was examined using qPCR to understand growth in fish species better. Muscle tissue samples (n=480) from 160 individuals of the same age were collected from three species (L. rohita, C. catla, and C. mrigala). Individuals were divided into two groups (high-weight and low-weight groups), cultured under normal conditions. The housekeeping gene β-actin validated GH expression in fast and slow-growing fishes from the same species. Results showed that GH expression varies across species and fish specimens that overweight their counterpart feature have higher GH expression. A selection for overweight fish in the aquaculture breeding systems is preferable as those fish could inherit their genomics to the future cohort, enhancing production, and commercial profit for farmers. Comprehensive research about different growth genes and the environmental aspects that influence fish growth is mandatory. No work has been reported regarding the growth gene analysis of fish from Pakistan. This report was Pakistan's first and baseline study regarding growth analysis of main culturable fish species at the molecular level.