We compared the effects of two sets of growth conditions, high temperature (34°C) plus high salinity (9‰) [treatment 34°C-9‰], and an ambient temperature of 28°C plus freshwater (0‰) [treatment 28°C-0‰] on survival, growth and the utilization of energy, protein and amino acids in snakehead, Channa striata at feeding rates of 0 (fasting), 25%, 50%, 75%, 85% and 100% (apparent satiation) for 26 days. Fingerlings of uniform weight (7-8 g) were acclimated to the water conditions for seven days before being assigned randomly to 250L composite tanks with the designed temperature and salinity, at a density of 30 fingerlings per tank. Fingerlings were fed commercial feed formulated for snakehead. Fingerling weight, and content in the fish body of crude fat, crude protein and amino acids were measured at the start and at the end of the feeding experiment. Snakehead fingerlings cultured at 28°C-0‰ had higher final weight, greater weight gain, better survival, and higher feed intake, and a lower feed conversion ratio than fingerlings cultured at 34°C-9‰. Fingerlings cultured at 28°C-0‰ had significantly higher amino acid digestibility coefficients and maintenance requirements for energy, protein, and amino acids than those at 34°C-9‰, but conversely, utilization rates were lower at 28°C- 0‰ than at 34°C-9‰. For typical ambient conditions of 28°C-0‰, maintenance requirements and utilization rate were, respectively, 44.8 KJ·kg-0.82 day-1 and 0.49 for energy, 0.44 g·kg-0.76 day-1 and 0.58 for protein, and from 0.014 to 0.050 g·kg-0.76 day-1 and 0.41 to 0.64 for essential amino acids. These results imply that snakehead cultured at a combination of high temperature and high salinity requires high levels of dietary energy and protein to satisfy their maintenance requirements.
Tạp chí khoa học Trường Đại học Cần Thơ
Lầu 4, Nhà Điều Hành, Khu II, đường 3/2, P. Xuân Khánh, Q. Ninh Kiều, TP. Cần Thơ
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