Introduction
Aquaculture has persistently developed globally under best practices. A good health status from the function point of view is preponderant for both cultured and wild fish species in early development (Mota et al., 2019). Poor health precludes the reduced exponent of the fish to perform its physiological functions, conform to stressful conditions, and prevent disease (Caipang et al., 2015). Lofty intake of protein above 25% by both fin and shellfish is remarkably excreted as ammonia-nitrogen and influence the quality of water. When inorganic nitrogen, total suspended solids (TSS) are high in concentration in culture water, it leads to death of culture species, diseases, accumulation of harmful residues in culture systems (Karunaarachchi et al., 2018), and obstruction of the growth of global aquaculture market (Caipang et al., 2015). To promote efficient fish production, recycling aquaculture system though expensive to maintain, is most preferable. Therefore, it is apropos to utilize non-expendable ecological clues to resolve the problems associated with cost, poor fish production, etc. However, inappropriate husbandry conditions such as poor water quality, crowding leading to accentuated social interactions between similar schemes present in the culture strategies are a potential threat to animal health/welfare. Therefore, biofloc technology (BFT) provides an alternate solution as a consequence of practicing zero-water exchange, waste nutrient recycling (Bossier and Ekasari, 2017) regulating water qualities by microbial communities, promoting fish growth (Hamidaghli et al., 2019) with reduced environmental impact (Bossier and Ekasari, 2017) for sustainable aquaculture. It is a more beneficial system when heterotrophic bacteria, a nitrogen conversion agent is stimulated by adjusting the C:N ratio in the culture system by the addition of carbonaceous plant-based material or equivalent inorganic carbons for sustainable fish production to achieve sustainable development goals (Bossier and Ekasari, 2017). It has also offered practical solutions to effective water quality control (Avnimelech, 2007) and improvement of fish growth in the healthy culture system (Lananan et al., 2014).
Materials and Methods
A 28 days preliminary trial was conducted to evaluate the affect of biofloc technology application on Clarias gariepinus juveniles with emphasis on the growth performance and impact on physiological status. A total of two hundred and seventy juvenile Clarias gariepinus were randomly distributed into six plastic bioreactors groups (A F) in triplicates with equal volume of inoculum, maintained in 30 L tank with constant aeration. Addition of organic carbon sources (CN 10:1, 20:1) were evaluated to stimulate rapid growth of microbial dynamics biomass whereas, no carbon sources were added in the control systems. The CN ratios (cassava and wheat) of 10:1 and 20:1 were; cassava (CA 10:1, 20:1) groups C, D, and wheat flour (WH10:1 and 20:1) groups E and F, respectively. Meanwhile, the normal controls, group A (inoculum, no carbon addition) and B (no inoculum, no carbon) had 50% water exchange and received only fish feed at 3% body weight.
Result
The physicochemical parameters maintained the tolerable limit for catfish farming. Significant weight gain, specific growth rate, Length Weigh Relationship (LWRs), survival rate, and floc volumes were observed at the end of experiment. Observed changes in the catalase, superoxide dismutase, glutathione peroxidase, and malondialdehyde activities in the gill were between day 14 and 21. Significant levels (p1 of C. gariepinus juveniles within 28-days. inclusion of C:N ratio of cassava and wheat flour in biofloc tank is beneficial for the growth and health parameters of Clarias gariepinus.
Discussion
The adjustable C:N ratio of cassava and wheat flour in flocculation is essential, efficient, and indicated a positive reduction of inorganic nitrogen and noxious metabolites produced in the culture system of African catfish, Clarias gariepinus. It is pertinent to observe the peculiar attributes of natural carbohydrates sources such as locally available, not harmful to the cultured fin and shellfish, and cheap. Fish culture using BFT is more beneficial for better growth performances with a reduced pathophysiology change. CA 10: 1 and WH 20:1 is better utilized in Clarias gariepinus culture compared to CA 20:1 and WH 10: 1. There is a need to investigate other cheaper sources of carbohydrates such as white yam tuber (Dioscorea rotundata), water yam (Dioscorea alata), cocoyam (Xanthosoma sagittifolia, Coloca sia esculenta) and relevant agricultural by-product as natural carbon sources in culture of finfish in a biofloc media.
References
Avnimelech, Y (2007). Feeding with microbial bioflocs by tilapia in minimal discharge bioflocs technology ponds. Aquaculture., 264: 140–147.
Azim ME, Little DC (2006). Intensifying aquaculture production through new approaches to manipulating natural food. CAB Reviews: Perspectives in Agriculture, Vet. Sci. Nutrit. Nat. Resou. 062, 23 pp
Bossier P, Ekasari J (2017). Biofloc technology application in aquaculture to support sustainable development goals. Microb. Biotechnol. 10(5): 1012-1016.
Caipang C.M.A., Choo H.X., Bai Z., Hunag H, Lay-yag C.M. (2015). Viability of sweet potato flour as carbon source for the production of biofloc in freshwater culture of tilapia, Oreochromis sp. Int. Aquat. Res. 7(4): 329-336
Hamidoghli A., Won S., Aya F.A., Yun H., Bae J., Jang I., Bai S.C (2019). Dietary lipid requirement of white leg shrimp Litopenaeus vannamei juveniles cultured in biofloc system. Aquaculture Nutrition, 2019; 00:1–10. https://doi. org/10.1111/anu.13021
Karunaarchchi K.A.C.M., Kumari M.A.A.P., Adikari A.M.J.B., Nayananjalie W.A.D (2018). Effect of biofloc on growth of genetically improved farmed tilapia juveniles in indoor condition. Int. J. Fisher. Aquat. Sci. 6(4): 295-299.
Lananan F., Abdul Hamid S.H., Din W.N.S., Ali N.A., Khatoon H., Jusoh A., Endut A (2014). Symbiotic bioremediation of aquaculture wastewater in reducing ammonia and phosphorus utilizing Effective Microorganism (EM‐1) and microalgae (Chlorella sp.). Int. Biodeteriorat. Biodegrad. 95: 127–134. https://doi.org/10. 1016/j.ibiod.2014.06.013
Mota G.C.P., Figueiredo C.V., Campos D., Silva de Moraes L.B., Bruzaca D.N.A., Brito L.O., Gálvez A.O. (2019). Effect of the c:n ratio on Daphnia magna (Straus, 1820Bol. Inst. Pesca 2019, 45(3): e463. https://doi.org/10.20950/1678 2305.2019.45.3.463