The effect of different alkalinity levels on Emph

Authors: Plínio S Furtado Luis H Poersch Wilson Wasielesky

Publish Date: 2014/08/19

Volume: 23, Issue: 1, Pages: 345-358

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Abstract

The initial stages of rearing marine shrimp using biofloc technology BFT involve the biofloc formation process At the same time there is an increase in the levels of total suspended solids and a decrease in alkalinity and pH This reduction of alkalinity and pH occurs due to the consumption of inorganic carbon by the autotrophic bacteria present in the bioflocs and biofilms The aim of this study was to evaluate the effects of different alkalinities on water quality and the zootechnical performance of the marine shrimp Litopenaeus vannamei in a BFT system The experiment consisted of four treatments with three replicates each 75 150 225 and 300 mg CaCO3/L To maintain the alkalinity at the established level sodium bicarbonate was applied For the experiments twelve experimental units area = 020 m2 with an effective volume of 50 L were stocked with 30 juvenile L vannamei 020 ± 007 g to achieve a stocking density of 150 shrimps/m2 and were maintained for an experimental period of 49 days The 75 treatment presented the highest levels of ammonia and nitrite throughout the study compared to the 150 and 300 treatments The results showed that higher alkalinity favors biofloc formation and the establishment of nitrifying bacteriaThe authors are grateful for the financial support provided by the National Council for Scientific and Technological Development CNPq the Ministry of Fishery and Aquaculture MPA and the Coordination for the Improvement of Higher Level Personnel CAPES Special thanks to the Centro Oeste Rações SA GUABI for donating the diets WJ Wasielesky Jr and LH Poersch are research fellows of CNPq

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