Developmental responses of sterlet (Acipenser ruthenus) to temperature modulation with insights into intestinal and morphological traits.

Sturgeon fish are highly valued in aquaculture, relying on optimal water temperatures for health and productivity. In this study, three temperatures were considered including group A: (ambient temperature, 18 ºC), group B: 21 ºC and group C: 27 ºC to investigate the intestine morphology, growth performance, meristic and morphological traits of sterlet. For this purpose, the temperature was gradually increased, and the larvae were exposed at the desired temperature 32 days after fertilization (dpf) and then returned to ambient temperature until 64 dpf. The growth results indicated that temperature manipulation in the first two months of the life can improve growth. Examining the morphologic and meristic characteristics showed that the increase in temperature accelerates fin and skeletal development, in which the calcified structures such as lateral scutes, distal radials and spine of pectoral fin were detected in group C. The development of villi's was higher in group C than the other groups at 32 dpf and 64 dpf. Therefore, the results of this study demonstrated that short-term thermal tolerance of sterlet has a positive effect on growth performance, morphological traits and intestine development. Proper temperature control enhances sturgeon aquaculture in the first two months.