It is important to explore the use of alternative ingredients for soybean and fishmeal in aquaculture feeds because the demand and cost for those ingredients are expected to increase in the near future and long-term. Meanwhile, the food processing industry produces large quantities of wastes that often contain organic solids and nutrients (e.g. nitrogen waste and phosphorus) which can be converted in microbial protein (bioflocs) using suspended growth biological reactors. Bioflocs that were collected from such a reactor that treats confectionary food processing effluent water were dried and in shrimp feed as a replacement for soybean and fishmeal. A control diet (without bioflocs) was compared to three diets that replaced soybean (10, 20, and 30% biofloc inclusion) and two diets that replaced fishmeal (10 and 20% biofloc inclusion). The control and biofloc diets were formulated to be equivalent for levels of crude protein, total fat, crude fiber, calcium, magnesium, phosphorus, potassium, and sodium. Five juvenile shrimp were stocked per tank and each dietary treatment was tested using 8 replicates over a 35day feeding trial. Dietary treatments had some impact on shrimp performance. No differences (P>0.05) in shrimp performance were observed between the control and the diets that included bioflocs for survival (97.5 to 100%), growth (2.16 to 2.40g/wk), harvest biomass (687 to 732g/m2), or food conversion ratio (1.50 to 1.66). These results indicate the bioflocs harvested from a suspended growth biological reactor that treats food effluent water can successfully be used in shrimp diets.Alternative & sustainable protein source for shrimp culture.

Resumo: O objetivo deste trabalho foi avaliar a qualidade de água na produção de alevinos de tilápia-do-nilo alimentadas com diferentes níveis de proteína bruta (PB) em sistema experimental com bioflocos sem renovação de água. Foram utilizados 270 alevinos (6,31±0,40g), distribuídos aleatoriamente em 18 aquários de 200 L (15 animais/aquário), e que foram alimentados com três níveis 28%, 32% e 36% PB (tratamentos), durante 60 dias. Todas as rações experimentais foram formuladas para conter 3.200 kcal/kg de energia digestível. O delineamento experimental utilizado foi o inteiramente casualizado com três tratamentos e seis repetições. Os seguintes parâmetros de qualidade de água foram avaliados: temperatura, oxigênio dissolvido, pH, amônia, nitrito, nitrato, condutividade, alcalinidade, turbidez e volume de sólidos sedimentáveis. Os dados obtidos foram submetidos análise de variância (ANOVA), e complementadas com o teste de Tukey (p<0,05). Não foram encontradas diferenças (p>0,05) entre as médias dos parâmetros físicos e químicos da água. Por outro lado, para os valores de sólidos sedimentáveis houve diferença (p<0,05), sendo que os aquários onde os peixes foram alimentados com ração contendo 36% PB apresentaram maiores valores, quando comparado com o tratamento 28% PB, no entanto, eles não diferiram do tratamento 32% PB. O sistema bioflocos manteve os parâmetros físico-químicos da água em condições favoráveis para a produção de alevinos de tilápia-do-nilo sem renovação de água, independentemente dos três níveis utilizados de proteína das rações, resultando em melhor utilização do recurso hídrico e consequente diminuição da emissão de efluentes. Abstract: This study aimed to evaluate the water quality of Nile tilapia fingerling culture fed diets with different crude protein (CP) levels in an experimental biofloc system (BFT) with no water renovation. Fingerling (n=270, 6.31±0.40g) were distributed in 18 aquaria (200 L, 15 fish/aquarium) and fed with three levels 28%, 32% e 36% of CP (treatments), during 60 days. All experimental diets were formulated to be isoenergetic 3,200 kcal/kg of digestible energy. The experimental design was completely randomized with three treatments and six replicates. The following water quality parameters were evaluated: temperature, dissolved oxygen, pH, total ammonia, nitrite, nitrate, conductivity, alkalinity, turbidity and sedimentable solids. Experimental data were submitted to analysis of variance (ANOVA) and complemented with Tukey &#769;s test (p<0.05). There were no significant difference (p>0.05) among physical and chemical water parameters of different treatments. On the other hand, sedimentable solids showed statistical difference (p<0.05), and the aquaria where fish were fed with 36% CP showed the highest values compared to 28% CP; however, did not differ from 32% CP. The biofloc technology kept favorable water quality to Nile tilapia fingerling culture without water renovation independently of the three dietary protein levels, resulting in improved utilization of hydric resource, and consequent reduction of effluents emissions.