Effects of different rearing temperatures on muscle development and stress response in the early larval stages of Acipenser baerii

Innate immune and chronic heat stress responses in sturgeons: Advances and insights from studies on Russian sturgeons

Chronic stress deteriorates the immune function of fish, thereby increasing their vulnerability to infections. However, the molecular and cellular mechanisms underlying stress-mediated immunosuppression and infection susceptibility in fish remain largely unknown. Understanding these mechanisms will contribute to improving fish welfare and their farm production. Herein, we review the challenges of sturgeon aquaculture in subtropical countries, where current climate change has giving rise to significant temperature increments during summer. This leads to the exposure of fish to stressful conditions during these months. Chronic heat stress deserves attention considering the rapid warming rate of the planet. It is already affecting wild fish populations, with disastrous consequences for sturgeons, which are one of the most endangered fish species in the world. In this context, we discuss the most recent advances through the studies on the effects of chronic heat stress on the innate immune components of sturgeons. To this end, we summarise the findings of studies focusing on the aquaculture of Russian sturgeons and observations made on other Acipenser species. Special attention is given to acute-phase proteins, as they might be valuable biomarkers of heat stress and infection, with applicability in monitoring the fish health status in farms.

Rearing Environment during the Endogenous Feeding Stage of Acipenser baerii

The aim of this study was to evaluate behaviour, growth, lipid composition, muscle development, and stress status of Siberian sturgeon larvae reared with two types of substrate: Bioballs1 (BB1) and Bioballs2 (BB2), when compared to no substrate (CTR). Sampling points were: hatching (T0), schooling (T1), and yolk-sac full absorption (T2). BB1 larvae were less active and showed no schooling behaviour. At T1 and at T2, BB1 larvae showed a significantly higher weight and total length than larvae reared in either CTR or BB2 (p < 0.05). The lipid content of larvae decreased over time, with little relevant differences between groups. At T2, total muscle area, slow muscle area and fast muscle area were significantly higher in larvae reared in BB1 (p < 0.05). No significant differences in muscle proliferation were found between groups. Real Time PCR was used for evaluating the relative expression of a pool of genes: myod, myog, mrf4, igf2, hsp70, hsp90a, hsp90b, and glut2. The expression of these genes did not seem to be much affected by the type of rearing substrate, except for myog and hsp70 at T1, which was greater in BB2 larvae. Our data suggest that the presence of a substrate during this developmental period seems to have positive effects but further studies would be necessary during the exogenous feeding stage.

A journal of histochemistry as a forum for non-histochemical scientific societies

Histochemical techniques are widely applied in biomedical research and, during the last twenty years, they were among the methods used in more than 590,000 scientific articles in indexed journals. However, a very small percentage of these papers were published in strictly histochemical journals. A possible strategy to widen the audience of the histochemical journals making them attractive to non-histochemist authors might be to publish and make open-access available the proceedings of the meetings and conferences of valued scientific societies whose fellows use microscopy and histochemistry in their experimental activity. In the last years' experience of the European Journal of Histochemistry, this approach was effective to increase the number of published articles on stem cells and development, connective tissue and nerve cell biology.

Histochemistry as a versatile research toolkit in biological research, not only an applied discipline in pathology

The impressive progress of histochemistry over the last 50 years has led to setting up specific and sensitive techniques to describe dynamic events, through the detection of specific molecules in the very place where they exist in live cells. The scientific field where histochemistry has most largely been applied is histopathology, with the aim to identify disease-specific molecular markers or to elucidate the etiopathological mechanisms. Numerous authors did however apply histochemistry to a variety of other research fields; their interests range from the microanatomy of animal and plant organisms to the cellular mechanisms of life. This is especially apparent browsing the contents of the histochemical journals where the articles on subjects other than pathology are the majority; these journals still keep a pivotal role in the field of cell and tissue biology, while being a forum for a diverse range of biologists whose scientific interests expand the research horizon of histochemistry to ever novel subjects. Thus, histochemistry can always receive inspiring stimuli toward a continuous methodological refinement.