Biofloc technology application in Nile tilapia ( Oreochromis niloticus , L.) hatcheries: effect on the reproductive performance, offspring quality, growth performance, and physiological parameters of fry

Abstract

ABSTRACTThis study evaluated the potential of applying biofloc technology (BFT) in Nile tilapia (Oreochromis niloticus) hatcheries. The first experiment was conducted to determine the effect of maintaining tilapia broodstock in BFT system in terms of reproductive performance and offspring quality as compared with the conventional clear-water system. A total of 45-tilapia broodstock were reared for 2 months in each treatment. Females at advanced maturation were transferred to four spawning tanks (800 L) at a density of eight individuals per tank (3:1 female:male sex ratio). Two tanks were assigned to each of the two treatments (BFT and control). Reproduction took place over the course of 2 months, with all females being inspected weekly to verify the presence of eggs. The second trial (43 days) analyzed the effect of BFT system on growth performance, feed utilization, digestive enzymes activity, and antioxidant status in the early fry stages. A total of 540 larvae (8.7 ± 0.7 mg) were assigned to six glass aquariums (60 L capacity). One experimental group was reared using a BFT system with daily sugar addition at a C/N ratio of 15/1, in comparison to a control group reared in clear water. Fish were fed commercial pellets three times a day at various feeding ratios (6–9% of the fish body weight). The fecundity of tilapia, hatching rate, egg and larval size, and larval resistance to stress tests presented no significant differences among treatments (P > .05). After 20 days of larval rearing, the daily weight gain was 29% higher in BFT fish as compared to the control treatment. The BFT system had better feed conversion ratio than control treatment. The larvae reared in BFT system had significantly higher alpha-amylase and catalase activities than control (P < .05). Overall, these results suggest that the BFT system can be used in tilapia hatcheries for broodstock rearing without negative effects on reproductive performance. The better growth performances of larvae reared in BFT treatment justified the application of this system during nursery phase.KEYWORDS: Nile tilapiabioflocreproductionlarval qualityenzyme activity AcknowledgmentsThe authors would like to thank Ms Ferhane Djamila, the director of the marine fish farming experimental station (Bousmail, Algeria) to facilitate the conduct of experiments.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThe author(s) reported that there is no funding associated with the work featured in this article.