2021 Volume 69 Issue 1 Pages 43-53
The following feeding protocols were used to determine its influence on energy partitioning in Pacific bluefin tuna fingerlings weighing 1.8 g in a commercial-scale tank to improve fish husbandry; fasting (F), daily feeding at 2, 3, 4 and 5 times until satiety (2S, 3S, 4S and 5S, respectively), and 4 days feeding at 5 times daily until satiety followed by a fasting day (4/5S) with an artificial diet. When energy partitioning was expressed as percentages of gross energy intake, the sum of fecal, urinary and heat increment was near 40% on all feeding protocols, excepting F. The energy for standard metabolism was higher in 2S, followed by 4/5S, 3S, 4S and 5S groups. The highest retained energy (RE) of 24.4% was found in 5S, followed by 23.8% in 4S, 22.1% in 3S, 18.0% in 4/5S and 12.1% in 2S. Although there was no significant difference in final mean weight between groups 4S and 5S, that of 5S group showed significant difference than juveniles under 2S, 3S and 4/5S groups (P < 0.05). These results revealed that 4 or 5 times daily feeding until satiety will be recommended to ensure better growth, and that even a single day fasting after a 4-day satiety cause a remarkable RE reduction.
