Development of a water recirculating system for bullfrog production: technological innovation for small farmers

Abstract

Despite the technological progress in frog farming, issues related to the environment, biosafety, and the use of technologies that minimise environmental impacts are frequently neglected by farmers. With the goal of developing a low-cost technology for reuse and preservation of water quality, an anaerobic filtering system combined with an aerobic filtering system was implemented in the grow-out sector in the Frog Culture Research Unit at Fundação Instituto de Pesca do Estado do Rio de Janeiro (FIPERJ). The filtering system received the effluent from six pens of frogs that were populated with 362 frogs in different development phases. The efficiency of the filtering system was evaluated by an analysis of the water before and after passing through the filters. In addition to the standards of water quality, the animals' performance was also observed through monitoring rates of survival, weight gain and feed conversion ratio. The results showed the effectiveness of the filtering system by removing organic matter, on average 87%. The values of total ammonia and non-ionisable reached 1.04 and 0.004 mg/L, respectively. Also, frogs subjected to the system presented satisfactory rates of weight gain and a high survival rate (97%).Index terms: Frog farming; effluent treatment; environmental preservation; local development. RESUMOApesar da evolução tecnológica da ranicultura, ainda é possível perceber que as questões voltadas para o meio ambiente, biossegurança e emprego de tecnologias que reduzam o impacto ambiental, são frequentemente ignoradas pelos criadores. Com o objetivo de desenvolver uma tecnologia de baixo custo para reuso e preservação da água foi implantado um sistema de filtragem anaeróbia, acoplado à filtragem aeróbia, no setor de engorda inundado do ranário experimental da Fundação Instituto de Pesca do Rio de Janeiro (FIPERJ). O sistema de filtragem recebeu o efluente de seis baias de engorda. A eficiência do sistema foi avaliada, por meio da análise da água antes e depois da passagem nos filtros. Além dos padrões de qualidade da água foi observado o desempenho dos animais, por meio das taxas de sobrevivência, ganho de peso e conversão alimentar. Os resultados obtidos evidenciaram a eficiência do sistema, em média foram removidos 87% da matéria orgânica. Os valores médios de amônia total e amônia não ionizável, após a filtragem aeróbia, foram respectivamente 1.04 e 0.004 mg/L. Conclui-se, ainda, que as rãs submetidas ao sistema apresentaram taxas satisfatórias de ganho de peso, conversão alimentar e sobrevivência (97%).Termos para indexação: Ranicultura; tratamento de efluente; preservação do ambiente; desenvolvimento local.

Effects of Salinity on the Egg Fertilization, Hatching, and Tadpole Growth and Survival Rates of the Thailand Frog (Rana tigerina Dubois, 1981)

“…Advances in cultural technology have promoted the expansion of high-productivity frog farming under controlled conditions, both in terms of distinctive facilities for diferent life stages and control of water quality, nutrition regimes, and sanitation [13]; Olvera-Novoa [14,15]. Currently, many major frog producers are based in Asian (China and Taiwan) and Latin American (Brazil and Mexico) countries, while Europe and the United States of America are the largest frog importers worldwide [7,10,11,16,17]. Frog species are commonly used as meat sources, including European green frog (Pelophylax ridibundus Pallas, 1771), East Asian bullfrog (Hoplobatrachus rugulosus Wiegmann, 1834), and Rana species [18].…”

Qualidade Do Sêmen De Rã-Touro Em Diferentes Dosagens De Hormônio, Tempos De Coleta E De Resfriamento

“…nus) foram amostrados para os ensaios experimentais e estavam no setor de engorda em baias de formato circular de lona, cada baia apresenta 6,6 m2 de área útil, sendo ¾ da baia inundada e ¼ da baia com piso seco. O abastecimento de água consiste em sistema de recirculação de água, com passagem em biofiltro e a alimentação dos animais composta de ração comercial com 40% de proteína bruta (Mello et al, 2016).…”

Effect of Two Levels of Temperature and Natural and Artificial Photoperiod on Growth and Metamorphosis of Bullfrog Tadpoles in an Intensive Rearing System

“…; Mello et al. ). Since growth and timing of metamorphosis are affected by stocking density, aquaculturists have sought the highest density tolerated by the species in cultivation (Flores‐Nava and Vera‐Muñoz ).…”

“…Bullfrog farming has become an activity with great aquaculture potential that has presented an important technological consideration in several countries, particularly in Brazil, China, Ecuador, Indonesia, Mexico, Taiwan, and Thailand (Sipa uba-Tavares et al 2008;Mello et al 2016). Since growth and timing of metamorphosis are affected by stocking density, aquaculturists have sought the highest density tolerated by the species in cultivation (Flores-Nava and Vera-Muñoz 1999).…”