HSP70 expression in blood cells in diploid and triploid rainbow trouts as short-term stress thermal and welfare statement model

En la fisiología de los peces triploides, falta información sobre sus respuestas moleculares bajo estrés y cómo cuantificar los niveles o la intensidad del estrés. Por lo tanto, los objetivos de este ensayo fueron evaluar el patrón de HSP70 en las branquias, el corazón y los músculos de truchas arco iris diploides y triploides no estresadas, y en las células sanguíneas después de la exposición al estrés por calor para evaluar sus niveles de estrés. Se observó una detección inmunohistoquímica de HSP70 similar en las muestras de branquias, corazón y músculos en ambas ploidías. Sin embargo, la expresión de HSP70 en sangre varió entre ploidías durante el tiempo experimental. Las truchas diploides de control y estresadas mostraron niveles análogos de HSP70, pero las truchas triploides estresadas por calor mostraron niveles más bajos de HSP70 durante todo el experimento con diferencias observadas después de 12 h y 24 h. Se esperaba una mayor expresión de HSP70 en ambas ploidías una vez que esta proteína protege a las células contra una amplia gama de agentes perturbadores. Evidencias recientes mostraron que los peces triploides tienen una menor expresión génica y este hecho debe ser explorado en futuras investigaciones en truchas arcoíris. En conclusión, las comparaciones a lo largo del tiempo entre los niveles diploides y triploides de HSP70 en truchas podrían usarse en la evaluación del estrés y de bienestar.  In triploid fish physiology there is a lack of information about its molecular responses under stress and how to quantify the stress levels or intensity. Thus, the goals of this trial were to evaluate the pattern of HSP70 in the gills, heart and muscles of non-stressed diploid and triploid rainbow trouts, and in the blood cells after the exposure to heat stress in order to assess their stress levels. Similar HSP70 immunohistochemical detection in the gills, heart and muscles samples was seen in both ploidies. However, HSP70 expression in blood varied between ploidies over the experimental time. Control and stressed diploid trouts showed analogous HSP70 levels, but heat stressed triploid trouts showed lower HSP70 levels throughout the experiment with differences observable after 12h and 24h. It was expected higher HSP70 expression in both ploidies once this protein protects the cells against a wide range of disturbing agents. Recent evidences showed that triploid fishes have lower gene expression and this fact must be explored in future investigation in rainbow trouts. In conclusion, comparisons over time between diploid and triploid HSP70 levels in trouts could be used in stress evaluation and welfare statement

Effect of dietary supplements in American bullfrogs reared in low and high stocking densities

The aim of this study was to evaluate the effect of the probiotic Bacillus subtillis and beta-glucan from the fungus Agaricus blazei on survival, growth and immunological capacity in bullfrogs (Lithobates catesbeianus) cultured in low and high stocking densities. Animals weighing 24.3 ± 2.38 g were randomly distributed into four treatments with four simultaneous replicates: D100: 100 frogs/m2 (control); D236: 236 frogs/m2; D236 + Prob.: 236 frogs/m2 supplemented with probiotic; and D236 + BG: 236 frogs/m2 supplemented with beta-glucan. The parameters evaluated were weight gain, survival, plasma corticosterone (CORT), phagocytic capacity (PC) and phagocytic index (PI), at 24 h and 15 and 30 days. There is significant interaction between treatments and time for CORT levels. At 30 days, these values were very close for the D100 (control) and D236 + BG groups. Meanwhile, no statistical differences were observed between treatments for PC and PI. These results indicate that beta-glucan reduced the effects of stress caused by high density in bullfrogs, but the probiotic did not reduce these effects. Both compounds are not efficient at increasing survival rates, weight gain and neither immune response of animals. Thus, the use of commercial food additives may not have the favorable impact desired by the farmer. Their use in aquaculture should be further studied in experiments involving a longer trial period and taking into account the cost of their use