Rearing temperature effects on growth, muscle morphology and gene expression of Tilapia, Oreochromis mossambicus

Abstract

Oreochromis mossambicus, tilapia is a fast growing fish able to adapt to a range of environmental conditions. The study was conducted with the aim to understand the effect of rearing temperatures on juvenile tilapia growth, muscle cellularity and expression of myoD and myostatin genes. Tilapia larvae were reared at 25°C, 30°C and 34°C for 60 days. Fish growth was measured in terms of body weight, white muscle fibre frequency and qRT-PCR based expression of myoD and myostatin gene. At 60 day, tilapia juveniles reared at 30°C grew significantly higher than the 25°C and 34°C, the frequency distribution of white muscle fibres in the <25 µm diameter class was similar at 25°C and 30°C but was significantly higher for fishes reared at 34°C and of white muscle fibre of diameter 25-50 µm was significantly higher at 30°C in comparison to 25°C and 34°C. MyoD gene expression was significantly higher in 34°C than 25°C and 30°C. Whereas myostatin expression was similar at all three rearing temperature. The present investigation suggests that rearing temperature affects fish growth, muscle cellularity and gene expression in juvenile tilapia.