Mineral status of Pangasius pangasius (Hamilton) fingerlings in relation to supplemental phytase:: absorption, whole-body and bone mineral content

A 60-day feeding trial was conducted to quantify the effects of microbial phytase supplementation on apparent absorption, whole body and bone contents of minerals in Pangasius pangasius fingerlings. Seven isoprotein (35.67%) and isocaloric (3870 kcal kg(-1)) diets were prepared with graded levels of supplemental phytase at 0 (T-1), 150 (T-2), 250 (T-3), 350 (T-4), 500 (T-5), 1000 (T-6) and 2000 (T-7) FTU (Phytase Units) kg(-1). Three hundred and fifteen fingerlings of P. pangasius (1.97-2.05 g) were randomly distributed in seven treatments with three replicates each. There was significant increase (P<0.05) in tissue protein content in phytase-supplemented groups compared with the control. Apparent absorptions of calcium (Ca), phosphorus (P), magnesium (Mg), manganese (Mn), zinc (Zn), iron (Fe), potassium (K), copper (Cu) and cobalt (Co) were significantly (P<0.05) higher in the phytase-supplemented groups than the control group. Faecal ash and P contents were significantly (P<0.05) higher in the control (T-1) than the phytase-supplemented groups. Whole-body contents of Ca, P, Zn, Fe, Cu and Co were significantly (P<0.05) improved by the dietary supplementation of phytase-barring Mg and Mn. Concentrations of bone Ca, P, K, Cu and Co were significantly (P<0.05) higher in phytase-supplemented groups. Bone ash contents (40.77-44.85%) were increased concomitantly with the increased level of phytase inclusion upto 500 FTU kg(-1) diet. It was observed that a minimum dose of 250 FTU phytase kg(-1) diet improved the mineral absorption and utilization in P. pangasius fingerlings.