Temperature effect on muscle growth in acipenser baeri yolk-sac larvae

In intensive aquaculture, fish species are constantly exposed to environmental stressful conditions, among which, temperature and stocking density are considered the major ones that may have an impact on the physiology, health, welfare and behaviour of cultures fish (1). The aim of the current study was to investigate the stress impact and muscle growth in precocious stages of Acipenser baerii subjected to three rearing temperatures. After hatching, larvae were subjected to three different rearing temperatures (16°C, 19°C and 22°C) until the yolk-sac was completely absorbed. Larvae were sampled at hatching, schooling and complete yolk-sac absorption. Histological, histometrical, histochemical and immunohistochemical analyses were executed, with the scope of evaluating muscle growth and development (total fibres area, fast fibres area, slow fibres area; anti proliferating cell nuclear antigen; anti-caspasi) and stress biomarkers (heat shock protein 70 and 90) were assessed. SAS software (v. 9.3, Cary Inc., NC) was used to perform statistical analysis. Total Fibres Area (TFA) and Fast Fibres Area (FFA) were higher in the schooling stage at 19°C; no differences were found regarding the Slow Fibres Area (SFA) at the tested temperatures. A significantly higher number of proliferating cells was observed in the schooling phase at 22°C than at 16°C, which is in accordance with another study on Siberian sturgeon (2). The anti-caspase immunohistochemistry was never observed in the larvae at any temperature. HPS70-immunopositivity was not observed in the muscle and HSP90 immunopositivity was evident at 19°C, which appears in full accordance with a part of a study on HSP’s (3). This study indicates that a lower rearing temperature would appear more appropriate for Siberian sturgeon larvae rearing, but further studies are necessary to deepen the effect of temperature on a mid-long term basis. (1) Pankhurst NW, King HR. J Fish Biol 2010,76:69-85. (2) Daczewska M, Saczko J. Folia biol (Kraków). 2005;53:29-38.