Variações sazonais do metabolismo energético e do balanço oxidativo em Parastacus brasiliensis promatensis (Crustacea, Decapoda, Parastacidae)

• Autor(a) principal: Pinheiro, Ludimila Carneiro
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/6017
• topic: ZOOLOGIA; DECÁPODOS; CRUSTÁCEOS; CIENCIAS BIOLOGICAS::ZOOLOGIA

Benthic macroinvertebrates occupy a critical position in the food chain, since they are responsible for the exchange of energy between basal resources and higher trophic levels. In order to analyze the physiological behavior of the species throughout the year, we collected 69 individuals of Parastacus brasiliensis promatensis in the central month of each season. The animals collected were measured for carapace length, taking as a criterion the minimum value for capture 20mm after hemolymph were removed in medium containing 10% potassium oxalate (anticoagulant) and left on ice for 24 hours to use only plasma in the analyzes. After capturing the animals were sacrificed by Cryoanesthesia. A water sample from Garapiá stream (San Francisco de Paula, RS) for analysis of physical and chemical parameters was collected. In laboratory subjects were weighed on the total weight and tissue weight to determine the rates of gastric fullness and hepatossomatic, in both genders, and gonadosomatic only in females; as well as the degree of gastric fullness. In the hemolymph were quantified by spectrophotometry proteins, lactate, lipids, triglycerides, glycerol, glucose, cholesterol, VLDL e HDL and glucose. Also analyzed the behavior of three antioxidant enzymes, which were superoxide dismutase, catalase and glutathione s-transferase; as well as a cellular damage measure (lipid peroxidation), in order to describe the oxidative status of this subspecies in different seasons. These analyzes were performed by spectrophotometric methods, gills, in hepatopancreas and abdominal muscle for both genders and in the gonads in females. Data were analyzed by one-way ANOVA followed by Bonferroni or Kruska-Wallis followed by Dunn (17.0 SPSS- or Bioestat). The statistical analysis indicated that there was difference between IH and IG of females throughout the study period. In the spring (reproductive peak) observed an increase in the IG and reduced IH, suggesting allocation of energy hepatopancreas reserves to the gonads; hypothesis reinforced by the analysis of IH in males, where there was no significant difference. Gastric index showed a reduction (p <0.05) in both sexes, in winter which combined with a decrease in ambient temperature and blood glucose control suggest a decreased metabolic rate and habitat exploitation, with possible use of endogenous reserves; combined with a decrease in glycerol and protein in the autumn transition to winter. Both genders showed differences (p <0.5) for lactate levels, as levels possibly linking up with low dissolved oxygen content (3,31 mg / l) in the summer. There was also a significant increase across the lipid chain in both sexes but more pronounced in females in the period corresponding to the apex of reproduction, and the probable cause reproductive preparation directly or increased energy expenditure in this situation. As for oxidative stress, the results suggest that females have a large energy expenditure in protecting the gonadal tissue, especially in the spring (playback apex) while maintaining a high degree of GST enzyme activity, together with the lesser extent of cellular damage when compared with the other tissues. As for the males lipid peroxidation level was higher in the spring, in all tissues. However, the gill tissue proved unable to increase antioxidant activity, and only the muscle and hepatopancreas were able to increase the enzymatic defense in the spring. We can conclude that seasonal factors clearly influence the biological cycle of P. brasiliensis promatensis and demand adjustments in the oxidative balance, requiring a greater demand of enzymatic antioxidant defenses and of the metabolic system.