Effect of dietary calcium on growth and survival of silver catfish fingerlings, Rhamdia quelen (Heptapteridae), exposed to different water pH |
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Authors: | C.E. COPATTI,I.J. COLDEBELLA,J. RADÜ NZ NETO,L.O. GARCIA,M.C. DA ROCHA,& B. BALDISSEROTTO |
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Affiliation: | Departamento de Fisiologia;;Departamento de Ciências Biológicas, Universidade Regional Integrada do Alto Uruguai e das Missões, Frederico Westphalen, RS, Brazil;;Departamento de Zootecnia, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil |
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Abstract: | The purpose of this study was to verify the effect of dietary Ca2+ on the growth and survival of silver catfish fingerlings (Rhamdia quelen) exposed to different water pH (5.5, 7.5 and 9.0). Silver catfish fingerlings were randomly placed in a thermoregulated water re‐use system with twelve 250 L‐tanks, two 1000 L‐biofilters and a 2000 L‐reservoir with a medium flow of 3.84 L min?1 tank. Stocking density was 0.16 fingerlings L?1. To prepare the treatment diets, the control diet (0.8 g kg?1 Ca2+) was supplemented with CaCO3 to yield experimental diets with 6.4, 9.5 and 23.9 g kg?1 Ca2+. There were three replicates/treatments. Survival was more than 93.9% in all treatments. Exposure of silver catfish fingerlings to alkaline or acid water reduced growth, and this effect was not ameliorated by dietary Ca2+ supplementation. Moreover, when fingerlings were maintained in water with pH 7.5, the best dietary Ca2+ range for silver catfish fingerling growth was 0.8–6.4 g kg?1. |
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Keywords: | dietary Ca2+ growth pH silver catfish survival |
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