Effect of using low molecular weight Chitosan on water quality, quality indices and stress reduction of Nile tilapia

Abstract

The study investigated the efficiency of adding extracted chitosan from shrimp wastes to enhance water quality, reduce stress and enhance tilapia flesh quality. Water quality parameters showed no significant differences among all treatments in (Dissolved oxygen, Temperature, pH, NO2 and Orthophosphate values). Treatment fish water with chitosan affected some nitrogenous parameters such as NH3 and NO3, where the values were (0.7, 0.6, 0.1 and 0.5 mg / l) for NH3, and (0.62, 0.61, 0.36 and 0.59 mg / l) for NO3, respectively. The lowest value of NH3 and NO3 was recorded in T3 (15 mg / l chitosan) followed by T4 (20 mg / l chitosan), T2 (10 mg / l chitosan) and finally T1 (negative control). Chemical composition of the samples revieled that the adding chitosan to the water improved moisture, protein, fat and increased ash content for fish flesh respectively, followed by control. Physiochemical quality parameters such as pH, acid value, Free amino nitrogen (FAN), Free fatty acids (FFA), total volatile bases nitrogen (TVB-N) and trimethylamine (TMA-N) showed that the addition chitosan reduce the increase in this parameters of the three treatments compared to the control The blood chemistry indices revealed that; T3 had the lowest AST; T4 had the lowest ALT values compared to control and T2, respectively. Despite the variation in Alb, Glob and ALP values among treatments they showed no significance differences. T3 showed the lowest values among all treatments for GLU, CHO, HDL, LDL and TG followed by T4, T2 and control, respectively.