Biofloc-based nursery production system: Heeding the call towards a sustainable shrimp culture industry in the Philippines

The increasing global population resulted in intense pressure on the food production sectors to meet the rise in food demand. The aquaculture industry, which is one of the major food production sectors, provides opportunities in addressing issues on malnutrition and poverty alleviation. Shrimp farming is an important sub-sector in aquaculture because shrimp are not only good sources of food, but they contribute to the national economy through export revenues. This resulted in the rapid intensification of shrimp aquaculture, which created negative issues on sustainability and environmental impacts. Hence, this necessitates an urgent need to develop aquaculture production systems that yield high productivity and profitability yet possess a low carbon footprint. Biofloc technology (BFT) fit into these criteria as this technology permits intensive culture of aquatic species, less use of resources, and improved water quality as a consequence of the production and activity of beneficial microbial biomass, which, at the same time, can be utilized as a source of feed for the growing shrimp. BFT has been shown to be successful on a commercial scale during shrimp grow-out, and recent studies have shown that this technology can be further refined and optimized for the production of shrimp during the nursery phase. This review, therefore, highlights the basics of BFT and how this technology is being optimized in the production of shrimp during the nursery phase. More specifically, this discusses the benefits of this approach in ensuring a productive yet sustainable way of producing shrimp in the context of Philippine aquaculture.This research study is part of the project, “Bioflocbased Nursery Tank Production of Shrimp for Quality and Sustainable Supply of Aquaculture Products in the New Normal” funded by the Department of Science and Technology (DOST) through the Science for Change Program (S4CP) – Collaborative Research and Development to Leverage Philippine Economy (CRADLE) and monitored by DOST – Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) with Project Number 8444 awarded to CMA Caipang. The authors gratefully acknowledge the support provided by the University of San Agustin and Marmi Agricultural Corporation

Rapid screening of potential probionts from the gut microbiota of climbing perch, Anabas testudineus

The intestinal microbial community has crucial functions for their vertebrate host. Several studies in fish showed that their gastro-intestinal tract harbors a diverse population of bacteria that supplies exogenous nutrients, enzymes, fatty acids and vitamins to their host. Most studies on probiotics involved their practical use for aquaculture, but are limited for the ornamental fish industry. Hence, this study aimed to screen the gut microbiota of a freshwater fish, Anabas testudineus, for potential probiotic candidates for the ornamental fish industry. Gut bacteria were obtained from the gut of climbing perch by plating of serially-diluted samples of the gut contents onto Nutrient Agar (NA). In vitro antagonistic activities of these gut bacteria against a fish bacterial pathogen, Aeromonas hydrophila, were determined by spot-on-lawn method. Isolates that had strong antagonistic activities against A. hydrophila were further characterized using standard staining and biochemical techniques. Rapid screening of the gut microbiota of climbing perch resulted in the identification of a promising probiont, Kurthia gibsonii through sequencing of its 16S rRNA gene. This bacterium is a member of the Planococcaceae family and is a Gram-positive, non-spore forming and rod-like bacterium. The isolate is yellowish in appearance and has a filamentous colony on nutrient agar. It exhibited catalase and amylase activities. Immersion challenge of freshwater ornamental fish with the bacterial isolate showed no mortality at 15 days after exposure. Taken together, the present study demonstrated that the gut microbiota of fish is a rich source of probiotic candidates that can be utilized during the culture of freshwater ornamental fish.This work is partly supported by the University of San Agustin Professorial Chair Research Grant titled, “Gut Microbiome: A Potential Source of Probiotic Candidates for Ornamental Fish” awarded to CMA Caipang. The authors of this paper would like to thank the support provided by their respective institutions; namely, the University of San Agustin and SEAFDEC Aquaculture Department during the preparation of the manuscript

Utilization of sodium bicarbonate as anesthetic during routine husbandry activities in ornamental fish

The tropical ornamental fish industry requires the stock to be reared in captivity before being sold; thus, exposing them to various handling- and transport-related stressors. A number of commercially available anesthetics are used during fish husbandry procedures, but these products are expensive and not readily available to small-scale ornamental fish operators. The use of sodium bicarbonate as an inexpensive anesthetic during routine husbandry activities in molly, Poecilia sp., a freshwater ornamental fish was assessed in terms of its effect on sedation, recovery and survival post-exposure in three independent experimental runs. Juvenile molly were exposed to sodium bicarbonate at a concentration of 100 g L−1 and the time to sedation and recovery were monitored. It took longer for the fish to be fully sedated than their recovery. Survival of the fish a week post-exposure ranged 40-60%. Simulated transport of fish for 6 hrs in water containing 1 g L−1 of sodium bicarbonate showed survival ranging 70-100% a week after transport. These findings demonstrated that sodium bicarbonate could be potentially used as a low-cost anesthetic during handling and short-term transport of ornamental fish. Future studies shall focus on discovering the underlying physiological mechanisms in fish following sedation with this chemical

Biofloc technology (BFT): A promising approach for the intensive production of ornamental fish

Biofloc technology (BFT) is an approach in the rearing of fish and shrimp as a means to support intensive culture, maintain optimum water quality, recycle the nutrients and reduce feed costs. The technology is primarily based on the principle of recycling nitrogenous wastes into microbial biomass that can be assimilated by the cultured animals as feeds or facilitates in maintaining good water quality. The rearing of larvae and juveniles of ornamental fish is confronted with issues on low survival rate, poor water quality and high incidence of diseases. These problems can be mitigated through the use of biofloc technology. From a number of studies reviewed, BFT offers a viable approach in ensuring sustainable production of ornamental fish. The benefits of using this technology include enhancement of water quality by reducing the levels of nitrogenous wastes, efficient feed conversion resulting in better growth and reduction in production costs and better immune response that will enable the fish to have higher resistance against infectious diseases.This work was partly supported by the University of San Agustin Professorial Chair Research Grant titled, “Gut Microbiome: A Potential Source of Probiotic Candidates for Ornamental Fish” awarded to CMA Caipang. The authors of this paper gratefully acknowledge the support provided by their respective institutions: the University of San Agustin and SEAFDEC Aquaculture Department during the preparation of the manuscript

Innofloc: Innovative biofloc technology for the nursery production of shrimp, Litopenaeus vannamei in tanks

Nursery systems are valuable production tools in shrimp aquaculture and are effective biosecurity facilities for the high-density culture of shrimp postlarvae (PL), resulting in healthy and uniform-sized juveniles. The nursery production of shrimp is usually carried out in small ponds; however, the use of small and circular tanks with plastic liners is gaining popularity. From an industry standpoint, there is a need to assess how nursery systems can improve the productivity of the shrimp production cycle. Hence, the use of small circular tanks coupled with the incorporation of biofloc technology was assessed in terms of its viability during the nursery production of the Pacific whiteleg shrimp, Litopenaeus vannamei. A 450m2 plastic-lined circular tank was installed and prepared for the stocking of L. vannamei postlarvae (PLs) at a density of 500 PLs per m2. Biofloc was produced and maintained throughout the nursery phase by adding brown sugar as a carbon source at carbon to nitrogen (C:N) ratio of 10. Daily monitoring of the various water quality parameters was carried out, while presumptive Vibrios were enumerated weekly. The shrimp juveniles were sampled for their body weight on the 14th day post-stocking and weekly until harvest on the 30th day of culture. The different water quality parameters were within optimum levels required for shrimp growth. Presumptive Vibrios were dominated by the yellow colonies. The shrimp attained 100% survival with an average body weight of 1.26 g and a feed conversion ratio (FCR) of 0.43 at the end of the nursery production phase. Our results indicate that the use of small circular tanks with biofloc during the nursery production phase of whiteleg shrimp is feasible and can be incorporated during the grow-out culture for improved and continuous production of this shrimp species.Department of Science and Technology (DOST) through the Science for Change Program (SC4P) – Collaborative Research and Development to Leverage Philippine Economy (CRADLE) for the funding and the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) for assisting and monitoring the project activities

An innovative biofloc technology for the nursery production of Pacific whiteleg shrimp, Penaeus vannamei in tanks

Nursery production of shrimp is usually done in small ponds; however, the use of small and circular tanks with plastic liners is gaining popularity. From an industry standpoint, there is still a need to assess how nursery systems can be of benefit to the shrimp production cycle. Hence, the use of small circular tanks coupled with the incorporation of biofloc technology was assessed in terms of its viability during the nursery production of the Pacific whiteleg shrimp, Penaeus vannamei. A 450m2 plastic lined circular tank was installed and prepared for the stocking of P. vannamei postlarvae (PLs) at a density of 500 PLs per m2. Biofloc was produced and maintained throughout the nursery phase using brown sugar as carbon source at a carbon to nitrogen (C:N) ratio of 10. Water quality was monitored daily, while presumptive Vibrios were enumerated weekly. Sampling for growth was done at the 14th day post-stocking and weekly until harvest on the 30th day. The different water quality parameters were within optimum levels required for shrimp growth. Presumptive Vibrios were dominated by the yellow colonies. At the end of the nursery phase, there was 100% survival and the shrimp attained an average body weight of 1.26 g and a feed conversion ratio (FCR) of 0.43. Our results indicate that the use of small circular tanks with biofloc during the nursery production phase of whiteleg shrimp is feasible and can be incorporated in the grow-out culture of this shrimp species.This research study is part of the project, “Bioflocbased Nursery Tank Production of Shrimp for Quality and Sustainable Supply of Aquaculture Products in the New Normal” funded by the Department of Science and Technology (DOST) through the Science for Change Program (S4CP) – Collaborative Research and Development to Leverage Philippine Economy (CRADLE) and monitored by DOST – Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) with Project Number 8444 awarded to CMA Caipang. The support provided by our respective institutional affiliations and Marmi Agricultural Corporation is gratefully acknowledged