Effect of temperature and its implications on the antioxidant system and immunological parameters of peneid shrimp
The exotic species Litopenaeus vannamei is the most cultivated worldwide, while native shrimp species such as Farfantepenaeus brasiliensis have already shown potential for cultivation. Environmental factors, such as temperature, can directly influence shrimp farming. Water temperature is one of the most important factors to be considered in aquaculture. Changes in water temperature can promote changes in oxygen consumption and availability to tissues, alter the solubility of gases in water and generally alter the metabolism of organisms. In the south of Brazil there is a wide thermal variation throughout the year so the temperature is a limiting factor in the region.Therefore, this thesis aimed to evaluate the effect of temperature on physiological and immunological parameters of both the exotic species Litopenaeus vannamei and the native shrimp F. brasiliensis. Short and long term experiments were carried out exposing L. vannamei shrimp to different temperatures and to biofloc and clear water culture systems for analysis of the antioxidant system and immunological parameters. In these experiments with the species L. vannamei, the animals from the treatments with the lowest temperatures 15 and 21ºC showed greater activity of antioxidant enzymes. This increased activity of the enzymes is an attempt to neutralize the reactive oxygen species, but a great deal of energy is required due to the stress condition, therefore less growth and survival were verified,because in many cases the animals did not endure the thermal condition to which they were exposed. A transport simulation experiment was carried out with the pink shrimp Farfatepenaeus brasiliensis at different temperatures to assess the influence of temperature on the antioxidant system during transport. The results showed that the best temperature was 19.3ºC, because with the reduced temperature, it increases the oxygen solubility and reduces the animals' metabolism which can result in a lower production of reactive oxygen species. In this condition the animals showed a better activity of antioxidant enzymes demonstrating a better physiological state to support the transport. Therefore, the recommended temperature for the transport of F. brasiliensis was 19.3ºC while for the L. species.vannamei it is recommended to cultivate in the biofloc system at a temperature of 27ºC in which the animals showed a better physiological state.