Evaluation of different concentrations of adult live Artemia (Artemia franciscana, Kellogs 1906) as natural exogenous feed on the water quality and production parameters of Litopenaeus vannamei (Boone 1931) pre-grown intensively

A 7-week experimental study was performed to evaluate the effect of five concentrations of adult live Artemia (0, 1, 2, 3 and 4 L-1) as exogenous natural feed on the water quality and production parameters of juvenile (0.2 +/- 0.01 g) shrimp (Litopenaeus vannamei) pre-grown intensively (125 organism m-2) under laboratory conditions (80 L plastic tanks). No significant differences were observed in the environmental variables among treatments. Total ammonium nitrogen, nitrates and phosphates recorded higher concentrations in all the treatments using artemia, as compared with the treatment without Artemia. In all the cases, the levels remained within or close to the ranges considered necessary for the farming of the species. The highest weight gain and biomass were obtained in the treatments with 3 and 4 Artemia L-1. The best feed conversion ratio were recorded using 2 Artemia L-1 and the highest with 0 Artemia L-1. No differences in survival were detected among treatments. The greatest concentrations of nitrogenous metabolites achieved at the highest densities of Artemia were lower than the LC50 for penaied shrimp and no negative effect was observed on the survival of the shrimp. These results clearly indicate that the use of adult live Artemia as exogenous natural feed significantly increased the production parameters of the Pacific white shrimp.