ABSTRACT
Juvenile T. rendalli were evaluated for 10 weeks to determine the effect of salinity on growth, feed utilization, and survival in tanks. Fish weighing 3.94 ± 0.44 g were stocked into twelve 50-L rectangular tanks at 15 fish /tank. The fish were raised in three salinity levels (5, 10, 15‰, and freshwater as a control). There were three replicate tanks per treatment. After the feeding experiment, a digestibility trial was conducted for two weeks. After 70 days, fish in the 10‰ treatment grew significantly larger (P < 0.05) than those in 5‰, 15‰, and freshwater. T. rendalli cultured in 10‰ had significantly lower feed conversion ratios and higher feed conversion efficiency and protein efficiency ratios. Survival of the fish was significantly (P < 0.05) different and depended on salinity level. The apparent digestibilities of crude protein, fat, ash, and gross energy were significantly higher (P < 0.05) in T. rendalli cultured in the 10‰ salinity treatment. However, apparent digestibility of dry matter did not differ significantly (P < 0.05) between 10‰ and 5‰. The results obtained indicate that 10‰ is optimal for T. rendalli in tank culture.
ACKNOWLEDGMENTS
The authors would like to thank the Canadian International Development Agency (CIDA) for funding the research, which was part of Ph.D. program pursued by the first author. Thanks to Bunda College of Agriculture, a constituent college of the University of Malawi, for making the facilities available for use during the research work. Thanks to Dr. T. Avery and Dr. D. Shneider for assistance rendered in statistical analyses. Thanks also go to the late Mr. A.G. Matambo.