AVALIAÇÃO DA ATIVIDADE DE ENZIMAS DIGESTIVAS EM HEPATOPÂNCREAS DE JUVENIS DE CAMARÃO DE ÁGUA DOCE (Macrobrachium rosenbergii)

Abstract

Among aquaculture activities, shrimp farming is considered one of the main activities, especially in the Northeast region of Brazil. This is mainly due to research related to food management. In this sense, it is necessary to give importance to the advances directed to the enzymology, considering that it can help in the adequate adjustment of the alimentary management so that a good system of shrimp production is obtained, with the possibility of reducing the cost by the use of appropriate ingredients in the feed formulation selected based on the digestive physiology of shrimp. Thus, the objective of this work was to quantify the proteolytic and amylolytic enzymatic activities in hepatopancreas of freshwater prawn, Macrobrachium rosenbergii, at different times of the 24 hour period. The experiment was carried out in the Laboratory of Carcinicultura- Campus III, and the analyzes were carried out at the Biotechnology Laboratory of Aquatic Organisms - Campus I, Federal University of Paraíba - UFPB. Six prawns with means weighting 5 g were stored in 5 experimental aquariums with dimensions of 60 cm x 30 cm x 40 cm. Each aquarium contained the bottom covered by biological plates, a layer of fiberglass wool, a layer of 5 cm of sand with small granulometry and a thermostat to maintain its constant temperature. In addition, a biofilter composed of layers of brittle aggregates, followed by coarse sand, fine sand and fiberglass wool, was installed over each aquarium, and, through of recirculation pumps submerged in the aquarium, the water was maintained in constant recirculation through the biofilter. As for toxic ammonia analysis, it was monitored every 3 days. The animals were kept in an environment under the influence of the natural photoperiod and fed 3 times a day, the ingested remains being removed from the aquarium by siphoning. After 14 days of physiological adaptation, randomly 2 animals were sacrificed every 2 hours. The shrimps were slaughtered by thermal shock by immersion in ice water. Afterwards, each animal was weighed, measured and dissected for removal of the hepatopancreas, for later biochemical analysis. In the biochemical procedure, the hepatopancreas of each animal was homogenized individually in 0.1M Tris-HCl pH8 buffer in a ratio of 1 g of tissue to 25 mL of the buffer, with the aid of a pistil to microcentrifuge tube. The supernatant (crude extract) was used for protein quantification, total proteolytic activity, tryptic activity and amylolytic activity of M. rosenbergii. Statistical analysis of the data was performed by the t-student test and the level of significance was ≤ 5%, with the aid of the Statistica 13.0 program. The results point to an increase in the proteolytic and amylolytic enzymatic activities in the diurnal period, probably due to the time of supply of the food to concentrate exclusively during this period, showing the effect that the presence of the food has on the production of digestive enzymes and their activities. We conclude that the major enzymatic activities of digestive proteases and amylase, in hepatopancreas of juveniles of Macrobrachium rosenbergii under laboratory conditions, presented during the diurnal period.