Stability and phosphorus leaching of tilapia feed in water

Guilherme Wolff Bueno,Aldi Feiden,Bruno Olivetti De Mattos,Wilson Rogério Boscolo,Dacley Hertes Neu,Fernanda Seles David

doi:10.1590/0103-8478cr20180429

Abstract

ABSTRACT: The present research aimed to investigate the stabil¬¬ity of pellets and phosphorus leaching of diets formulated for juveniles of Nile tilapia (Oreochromis niloticus), with different sources of phosphorus and different exposure times in water. Six diets were elaborated by varying the source of phosphorus (1 ‒ dicalcium phosphate (DP); 2 ‒ meat and bone meal (MBM); 3 ‒ poultry meal (PM); 4 ‒ anchovy meal (AM); 5 ‒ tilapia filleting industrial meal (TM); 6 ‒ calcined bone meal (CBM)) and, then, were submitted to four exposure times in water (5, 10, 15 and 20 minutes), with three replicates. Thus, 72 aquariums of 30‒liters were used, each being an experimental unit. All diets were evaluated for electrical conductivity of water, turgidity of pellets, mineral matter leaching, flotation of pellets, and total phosphorus leaching. Only turgidity and flotation of pellets varied with the different sources of phosphorus in the diets. The MBM diet had the highest turgidity of pellets. The PM, AM, and CBM diets had the highest flotation of pellets. The total phosphorus leaching had a linear effect with the increase of the exposure time, showing a greater release of phosphorus in the water with increase of exposure time. Data showed that PM, AM, and CBM diets had less potential impact on the aquatic environment. Conversely, the TM diet has greater polluting potential. These results showed that diets formulated with different sources of phosphorus exhibit distinct actions in the water, providing different effects on the fish culture environment.

Highlights

Aquaculture is expanding worldwide, especially in the last 20 years, and this trend is likely to continue (FAO, 2017)
Experimental diets Six diets were elaborated with the following sources of phosphorus: 1 ‒ dicalcium phosphate (DP); reference diet, 2 ‒ meat and bone meal (MBM), 3 ‒ poultry meal (PM), 4 ‒ anchovy meal (AM), 5 ‒ tilapia filleting industrial meal (TM), and 6 ‒ calcined bone meal (CBM)
Diets formulated with poultry meal (PM), anchovy meal (AM), and calcined bone meal (CBM) had the highest flotation of pellets

Summary

Introduction

Aquaculture is expanding worldwide, especially in the last 20 years, and this trend is likely to continue (FAO, 2017). In 2016, the global production of fisheries and aquaculture reached approximately 200 million tonnes of fish, of which 47% came from aquaculture (FAO, 2018). This activity is an important source of high quality protein, mainly in developing countries that need to increase food production for local consumption (El-Gayar & Leung, 2000). (BUENO et al, 2016; HARDY, 2010) These diets, when in contact with the water, lose nutrients and, when not consumed, raise nutrient concentrations in the environment (Soares-Júnior et al, 2007; Oliveira-Segundo et al, 2013). Among the nutrients lost from diets, phosphorus is the most critical, since it influences directly the eutrophication process (Martin et al, 2010; Han et al, 2016; Wang et al, 2016)

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Conclusion