Feed restriction and compensatory growth of the Nile tilapia, Oreochromis niloticus under Biofloc system condition | ||
| Egyptian Journal of Aquatic Biology and Fisheries | ||
| Article 68, Volume 26, Issue 4, July and August 2022, Pages 1171-1191 PDF (841.26 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejabf.2022.256394 | ||
| Author | ||
| Ahmed M. Aboseif et al. | ||
| Abstract | ||
| For compensatory growth of Nile tilapia, a 182-day feeding trial was conducted to evaluate the effects of bioflocs nutritional content. The three cyclical regimes of feed deprivation and re-feeding were R0:F7 (feed restriction 0 days, feeding 7 days), R2:F5 (feed restriction 2 days, feeding 5 days), and R4:F3 (feed restriction 4 days, feeding 3 days). There were significant differences in floc volume, total alkalinity, ammonia, nitrite, and nitrate, between treatments, according to the results of the experiment. Surprisingly, we found that the number of bacteria in the digestive tract of tilapia was significantly higher than that found in water samples. From 60×104 to 220×107 CFU g -1 of aerobic plate count (APC) were found in the gut. The bioflocs in the R0:F7, R2:F5 and R4:F3 groups had average crude protein contents of 33.42± 1.32%, 30.99± 0.98%, and 29.65± 1.06%, respectively. Twenty-six phytoplankton species were found in the fish gut, including genera from Cyanobacteria, Bacillariophyta, Chlorophyta, and Euglenozoa phyla. At the beginning and end of the experiment, 12 and 10 species of zooplankton were found in the biofloc system, respectively. The growth performance in terms of final body weight, weight gain, and specific growth rate) of the Nile tilapia in treatment R2:F5 was significantly higher (P<0.05) than that obtained in the treatment R4:F3 and slightly increased (P>0.05) in treatment R0:F7. Lipid content tended to decrease significantly (P<0.05) in feed deprivation treatment more than in continuous feed treatment. However, total serum protein, cholesterol, triglycerides, and immunoglobulin showed significant differences (P<0.05) between regimens, with the highest value in R0:F7 and the lowest value observed in both R2:F5 and R4:F3 experimental feeding restrictions. Overall, these findings suggest that growth compensation induced by cycles of feed deprivation and re-feeding treatment R2:F5 does confer a huge advantage in enhancing the growth performance and immunoglobulin biofloc system. | ||
| Keywords | ||
| Nile tilapia; feed restriction; compensatory growth; water quality; Aerobic Plate Count; plankton community; blood content | ||
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