Haematological and Biochemical changes of prawn in different water temperatures

Abstract

This study was conducted to evaluate the effects of different ambient water temperatures on growth, physical appearance, histology (blood, gills) and biochemical compositions of freshwater prawns raised under standardized culture conditions. Prawns averaging 14.5 to 22.0g were stocked into four controlled groups glass aquarium with aeration during the experiment period. Prawns in all control groups were fed twice daily according to a computer generated feeding schedule. Treatment groups prawns weight was less then controlled group after experiment. During the rearing period, the effect of four water temperatures (26°C, 30°C, 34°C and 38°C) on survivality and mortality rate, number of molts, and growth rate (molt increment and intermolt period) of Macrobrachium rosenbergii, prawns was evaluated in laboratory conditions. The experimental species showed some similarities in the both survival and growth pattern at different temperatures. The survival rate was the highest at 26°C and 30°C and decreasing at the highest temperature (38°C) after collecting haemocyte from the body. The number of molts was increased at higher temperatures for M .rosenbergii, corresponding those values to 26°C and 30°C, respectively. The size increment by molting was increased significantly (P<0.05) from 30°C to 38°C, whereas a reduction in the growth of prawns was observed at 38°C. Significant differences (P<O.05) among temperatures were found in some treatments in the haemocyte of Prawns before and after the experiment. Haemocytes were found to be in large number at 26°C to 30°C but decreasing with increased temperature like 38°C. Non granular and small granular, blood cell were large in number at this species of prawn. Histological changes of gills and haemocyte of M rosenbergii were examined. In histological experiments, a partial changes were observed in prawns gills chamber. In addition the biochemical composition of muscle was investigated during the Histological development of the studied species. In addition, the percentage of biochemical composition data indicated that the protein, moisture content was significantly decreased, while lipid and ash contents were increased during the experiment. The lowest protein content was found in the muscle of prawn at 38°C and the highest at 26°C. It was noted that the changes of components in the prawns muscle was related to the gradual increase of the temperatures at high level during the experiment.