The use of protozoan, rotifers and nematodes as live food for shrimp raised in bft system

Abstract

O Meio de Cultivo de Protozoarios e Nematodeos – PNCM, possibilita a producao de microrganismos de forma barata para a utilizacao como alimento vivo em cultivos de camaroes marinhos. Ciliados produzidos no PNCM foram testados como alimento vivo para pos-larvas de camaroes em um experimento com quatro tratamentos: (BFT) somente bioflocos; (BFT 10) 10 mL de PNCM adicionado ao biofloco; (BFT 100) 100 mL de PNCM adicionado ao biofloco; BFT 1000) 1000 mL de PNCM adicionado ao biofloco. Os microrganismos foram analisados nas fases inicial, intermediaria e final do experimento, realizado durante 30 dias. A analise do conteudo estomacal dos camaroes indicou a predacao dos ciliados pelas pos-larvas. Na maioria dos tratamentos, o periodo inicial foi marcado pelo incremento dos flagelados, a fase intermediaria foi marcada pela reducao na abundancia de ciliados, a fase final foi representada pelo aumento na abundancia de ciliados e rotiferos. Em todos os tratamentos, os nematodeos nao foram encontrados nas amostras finais, em nenhuma das tres fases de cultivo, sugerindo que estes organismos foram efetivamente predados pelos camaroes. Este estudo indicou que ciliados, rotiferos e nematodeos, desempenham importante papel como alimento vivo em larviculturas, principalmente pelo seu tamanho reduzido, valor nutricional e atratividade exercida sobre as pos-larvas.

The Protozoan and Nematodes Culture Medium – PNCM, enable inexpensively production of microorganism to be used as live food in shrimp culture. It was tested the ciliates produced by PNCM as live food for shrimp larvae in an experiment with four treatments: (BFT) only biofloc medium; (BFT 10) 10 mL of PNCM culture added to biofloc; (BFT 100) 100 mL of PNCM culture added to biofloc; and (BFT 1000) 1000 mL of PNCM culture added to biofloc. The microorganisms were analyzed at the beginning, intermediate and final phases of the experiment which lasted for 30 days. The analysis of shrimp gut contents indicated a predation of shrimps on the ciliates. In most treatments, in the initial period there was significant increase of flagellates, the intermediate phase was marked by the ciliates decrease and the final period was represented by an increase in the abundance of the ciliates and rotifers. Nematodes were absent at the end of the final phase in all treatments, suggesting that these organisms were effectively preyed by shrimps. This study indicate that ciliates, rotifers and nematodes play an important role as live food in hatcheries mainly due to their small size, nutritional value and attractivity exerted on shrimp postlarvae.