No abstract

Aquaculture is increasingly becoming more intensified leading to challenges to maintain optimal water quality conditions but also reducing effluent discharge to the environment. Therefore, the needs for the development of production systems that can ensure sustainable aquaculture production through minimizing the release of waste to the environment. Such technology should be easy to operate and available at a cheaper cost, both in installation and operations in order to suit the needs of both low and high‐income farmers. Biofloc technology is such a technology that can ensure sustainable aquaculture production, with low technical demands and it is available at a cheap cost. It is essentially a water quality management techniques, through manipulation of microbiota to convert the deleterious waste from aquaculture production to consumable body biomass and it has been established to have many other benefits asides from the intending water quality. This review discusses the developments of the biofloc technology, microbial interactions, important operational parameters and implication of the system to the disease and health management of cultured aquatic animals.

No abstract

In this study, African catfish (Clarias gariepinus) (9.68 ± 0.16 g, mean ± SE) were reared with biofloc technology (BFT) with three different carbon sources; raw rice bran (RRB) or when incubated (24 hr) with Bacillus species under aeration (cellular respiration, ResRB), or without aeration (fermentation, FerRB). The proximate composition, water solubility, and total soluble sugars of RRB, ResRB, and FerRB were measured. A control included fish cultured in a recirculating system. Water quality, biofloc production/proximate composition and subsequent effects to growth, feeding efficiencies, body proximate composition, and selected plasma biochemical parameters to triplicate groups of C. gariepinus were measured after 42 days. FerRB had the lowest crude fibre and higher total soluble sugars and water solubility compared to ResRB or RRB. Biofloc produced with FerRB had significantly higher (p < 0.05) crude protein. Ammonia‐N was significantly lower (p < 0.05) in the first 3 weeks in both control and FerRB treatments. Using FerRB significantly improved (p < 0.05) growth, feeding efficiencies, and whole‐body crude protein in African catfish compared to the control and ResRB. Therefore, using FerRB with BFT can be a highly effective strategy to create a zero‐exchange culture system while also significantly improving growth and feeding efficiencies of African catfish juveniles.

Global aquaculture production continue growing in order to meet up with ever increasing fish demand, especially as fish from capture has levelled off and makes an increase in aquaculture production as the only hope to meet the demand for fish. Aquaculture industry involves culture of many fish species of either fresh or brackish water origin and among the important freshwater fish species is North African catfish which is also called African catfish (Clarias gariepinus). Its production is increasing as the total aquaculture production also increases and its culture is spread globally, with Nigeria officially reported as producing the highest annual amount of the fish. There is a substantial culture of the fish in Malaysia, though not a native fish species but its presence in Malaysia is getting closer to over three decades and for almost a decade now, it has been the highest finfish produced in either fresh or brackish water aquaculture in Malaysia. This review discussed African catfish aquaculture in Malaysia and Nigeria, compared the production and prospects of the industry in the two countries.

No abstract

African catfish (Clarias gariepinus) and lemon fin barb hybrid (LFBH) (Hypsibarbus wetmorei ♂ × Barbodes gonionotus ♀) were cultured in either a biofloc technology (BFT) system or an individual recirculating aquaculture system (RAS) and their survival, growth, feeding efficiencies and biochemical composition were then compared after 8 weeks. LFBH and African catfish were chosen based on their different feeding habits. In the BFT treatments, glycerol was added to create a carbon to nitrogen ratio of 15, while the RAS system consisted of a fine mesh mechanical and biological filter. Each of the four treatments was triplicated, with each replicate consisting of 20 African catfish (0.98 ± 0.05 g) or LFBH (1.77 ± 0.02 g). Water quality and biofloc formation were examined weekly while the biofloc proximate composition was measured in weeks 5 and 8. During weeks 6, 7 and 8 the total viable bacterial colony forming units (CFU) were quantified. Regardless of species, biofloc formation was similar but the crude protein, lipid and ash significantly decreased from week 5 to week 8. However, biofloc crude protein and ash were significantly higher in the LFBH treatment. Total viable CFU were significantly higher (P < 0.05) in BFT compared to RAS, with LFBH having significantly more (P < 0.05) than African catfish. The proximate composition of the fish were unaffected by either system. Implementing BFT significantly (P < 0.05) improved both African catfish and LFBH growth, but this improvement was substantially higher for LFBH (41.6%) than for African catfish (7.6%). This may be due to a better ability of LFBH to consume smaller particles. Preliminary results also indicate that the nutritional composition of bioflocs could be influenced by biofloc age, which could have implications to solids management.

The performance of selected leaf meals of high dietary fibre in the feed of a tropical commercial carp, hybrid lemon fin barb (Barbonymus gonionotus ♀ × Hypsibarbus wetmorei ♂) was evaluated in a 56‐day feeding trial. The tropical carp juveniles (9.43 ± 0.05 g) were randomly stocked in 60‐L aquaria at 15 fish per aquarium. Five isonitrogenous and isocaloric diets (30% crude protein, 17 kJ/g gross energy) containing no leaf meal and 10% napier grass (Pennisetum purpureum), alfalfa (Medicago sativa), water spinach (Ipomea aquatica) and Gliricidia sepium leaf meals were formulated and tested. Three aquaria were randomly assigned to each experimental diet. The results showed that fish‐fed diets containing leaf meals showed superior growth performance and body composition which was better than those fed control diet. The leaf meal‐treated groups also had higher values of protein, lipid, energy retention and production of digestive enzymes amylase. Conclusively, the results indicated that leaf meal fibre provided better performance showing the inherent prebiotic effect of the utilization of these leaf meal in hybrid lemon fin barb .