ABSTRACT The objective of this study was to evaluate the effect of different stocking densities and the presence/absence of two artificial substrates on water quality and production rates of marine shrimp in a biofloc shrimp nursery culture. Two experiments were performed: different stocking densities with mosquito netting substrate and the presence/absence of polyester-type substrate. The first experiment lasted 38 days, and shrimp at an initial weight of 0.013±0.010 g were stocked in 24 tanks. The second experiment lasted 35 days, and shrimp at an initial weight of 0.037±0.002 g were stocked in six tanks. Weekly biometric measurements were performed to adjust the amount of feed. Suspended solids were higher at a density of 6000 PL m−3 and mosquito netting substrate. Final weight and specific growth rate were higher in treatments with mosquito netting substrate. However, survival was significantly lower with this substrate. Yield was significantly higher at a density of 6000 PL m−3. Polyester-type substrate had no significant effect on production rates or variables of water quality. However, this substrate could reduce the production of sludge. The results indicate that it is possible to culture shrimp in nursery stage up to 6000 PL m−3 in a biofloc system.

Resumo O objetivo deste trabalho foi avaliar o efeito de Lactobacillus plantarum sobre a conservação de mexilhões frescos e avaliar a atratividade, o consumo e a microbiota intestinal de reprodutores de camarão-branco-do-pacífico. O experimento avaliou mexilhões estocados com L. plantarum a 4ºC. Os controles foram: mexilhões estocados a -18ºC sem L. plantarum; mexilhões estocados a -18ºC com L. plantarum; e mexilhões estocados a 4ºC sem L. plantarum. As análises microbiológicas dos mexilhões foram realizadas nos dias 1, 7, 15, 30, 45 e 60 após o processamento. Além disso, os mexilhões conservados com L. plantarum e estocados a 4ºC e os mexilhões estocados a -18ºC sem L. plantarum, após 15 dias, foram avaliados quanto à atratividade, ao consumo e à microbiota bacteriana intestinal dos camarões. Mexilhões conservados com L. plantarum tiveram maiores contagens de bactérias ácido-lácticas e menores contagens de Vibrio spp., assim como de bactérias heterotróficas totais, após 60 dias de estocagem. Não foram observadas diferenças significativas quanto à atratividade ou ao consumo entre os tratamentos. A microbiota intestinal dos camarões alimentados com mexilhões conservados com L. plantarum apresentou maior contagem de bactérias ácido-lácticas e menor contagem de Vibrio spp. O uso de L. plantarum inibe Vibrio spp. e conserva o alimento, sem modificar a atratividade ou o consumo pelos camarões.

Abstract The objective of this work was to evaluate the effect of Lactobacillus plantarum on the preservation of fresh mussels and its effect on the attractiveness, consumption, and midgut bacterial microbiota of Pacific white shrimp broodstock. The experiment evaluated mussels stored with L. plantarum at 4ºC. The controls were: mussels stored at -18ºC without L. plantarum; mussels stored at -18ºC with L. plantarum; and mussels stored at 4ºC without L. plantarum. Microbiological analyses on mussels were performed on days 1, 7, 15, 30, 45, and 60 after processing. Additionally, mussels preserved with L. plantarum and stored at 4ºC, and mussels stored at -18ºC without L. plantarum were evaluated after 15 days for attractiveness, consumption, and midgut bacterial microbiota of shrimps. Mussels preserved with L. plantarum showed higher lactic acid bacteria counts and lower counts of Vibrio spp., as well as of total heterotrophic bacteria, after 60 days of storage. No differences were observed for attractiveness or consumption between treatments. The bacterial microbiota of midgut in shrimp fed mussels preserved with L. plantarum showed higher lactic acid bacteria count and lower Vibrio spp. The use of L. plantarum inhibits Vibrio spp. and preserves feed without changing attractiveness or consumption for shrimp.