Research And Applycation On The Effect Of Salinity On Growth Performance And Whole Body Composition Of Tambaqui(Colossoma Brachypomum) And Egyptian Moustache Catfish(Clarias Garepinus Valenciennes)

In this article, the freshwater fish speices tambaqui (Colossoma brachypomum), Egyptian moustache catfish (Clarias garepinus valenciennes) and tilapia(Oreochromis aureus × O. niloticus), which with a little salinity tolerance, were co-cultured with white shrimp (Litopenaeus vannamei) in the same culture system, and we expected to provide some scientific data for the polyculture of freshwater fish and white shrimp in the low-salinity ponds. This study including:(1) the effects of different salinity on the survival, growth and whole body composition of C. brachypomum and C. garepinus valenciennes, and the optimal salinity for the growth of C. brachypomum and C. garepinus valenciennes; (2) the effects of three freshwater fish species C. brachypomum, C. garepinus valenciennes and O. aureus × O. niloticus on the production performance of white shrimp. Results are showed as follows:1. A feed trial was conducted to evaluate the effect of salinity on growth performance and whole body composition of Colossoma brachypomum. The trial provided 4 levels of salinity as 0,4,8,12 abbreviated as B0, B4, B8 and B12 respectively. Each group has 3 parallels. Juvenile fish initial body weight was (13.80+1.20) g, was raised indoor system for 40d. The results showed that the survival rate, final body weight (FBW), weight gain(WG) and feed intake(FI) was lower (P< 0.05), but the feed conversion ratio (FCR) was higher in diet B12 than that of which in the other 3 diets (B0, B4 and B8). The FBW and WG was lower, but the FCR was higher in fish fed diet B0 than in fish fed diet B4 and B8 (P< 0.05) With the increase of salinity, specific growth rate (SGR) increased then decreased. The hepatosomatic index(HSI), viscersomatic index (VSI) intraperitoneal fat index (IFI) and crude fat were lower in diet B12 than in diets B0, B4 and B8 (P< 0.05). There were no significant differences of the whole body component of Colossoma brachypomum (crude protein, crude fat, ash and moisture) among the test diets(P> 0.05). When the salinity ranged from 4.0 to 8.0, the growth of Colossoma brachypomum could be enhanced while the on whole body composition were not influenced.2. A feeding trial was conducted to evaluate the effect of salinity on moustache catfish (Clarias garepinus valenciennes) growth performance and the composition of the whole fish. Salinity was set as 0、4and 8 (T0, T4 and T8).Moustache catfish was reared indoor system for 40d. In the trial, the survival rate was lower in diet TO than in diet T8 (P< 0.05). No significant differences were found in the weight gain (WG), specific growth rate (SGR) and feed intake of moustache catfish fed the test diets(P> 0.05). The condition factor (CF) was higher in diet TO than in diets T4 and T8 (P< 0.05). There were no significant difference in the:hepatosomatic index(HSI), viscersomatic index (VSI) and:intraperitoneal fat index (IFI) (P> 0.05). This study indicates that there’s no negative effect on moustache catfish growth performance and meat quality at the level of salinity 4-8.3. Two white shrimp Litopenaeus vannamei ponds were used in a 2-year study of the effects of introducing three freshwater fish species tambaqui(Colossoma brachypomum), Egyptian moustache catfish(Clarias garepinus valenciennes) and tilapia(Oreochromis aureus × O. niloticus) on the production performance of L. vannamei. Results showed that the survival, production, feed conversion ratio and income per unit of L. vannamei were not affected by the introduction of the three freshwater fish species(P> 0.05). Increasing the stocking biomass of L. vannamei and freshwater fish species could enhance the survival, income per unit and net profit of white shrimp(P> 0.05). It is indicated that the production performance of L. vannamei could not affected by the introduction of C. brachypomum, C. garepinus valenciennes and O. aureus× O. niloticus when the husbandry managements including shrimp-fish ratio, water level and feed supplementation were suitable.This study showed that there’s no harmful effect on the growth performance and the whole body composition of Colossoma brachypomum and Clarias garepinus valenciennes when the salinity ranged from 4.0 to 8.0, The production performance of L. vannamei could be improved with appropriate proportion of C. brachypomum, C. garepinus valenciennes and O. aureus x O. niloticus in white shrimp ponds.