Abstract

RUEDA-URIBE, Wilson E.; VASQUEZ-TORRES, Wálter  and  GUTIERREZ-ESPINOSA, Mariana C.. Phosphorous and proteindigestibility in phytase-supplemented rations in tilapia, Oreochromis sp.. Orinoquia [online]. 2012, vol.16, n.1, pp.21-29. ISSN 0121-3709.

The present study was aimed at evaluatingthe effect of phytase supplement on the digestibility of phosphorous andprotein in corn gluten (CG), hard wheat flour (HWF) and whole soya (WS) in redtilapia (Oreochromis sp.) diets. The chromium III oxide indirect labellingmethod was used for calculating the coefficients; fish faeces were collectedusing the modified Guelph system. Juvenile red tilapia weighing 100 g wereselected. The rations consisted of reference diet (RD) (69.5%), 0.5% inertmarker (chromium III oxide), the ingredient to be evaluated (30%) and phytasein 0.0, 500 and 1,000 units of phytase (PU)/kg diet for each of them. Theapparent digestibility coefficients (ADC) for the proteins obtained were 94.7%,84.5% and 90.3% without including phytase, 95.1%, 84.1% and 89.3% with 500 PUand 97.6%, 90.8% and 92.9% with 1,000 PU for CG, HWF and WS respectively.Regarding phosphorous ADC, the results for CG varied from 30.7% to 69.8%, 46.6%to 51.1% for HWF and 44.0% to 54.7% for WS. WS and HWF protein and phosphorousADC were not significantly affected by added phytase level (p>0.05);however, protein and phosphorous ADC tended to be greater when 1,000 PU wereadded. CG protein ADC had significant differences between the diet including 0PU of phytase and that containing 1,000 PU (p<0.05); there were phosphorous ADC differences between 500 PU and 1,000 PU.

Keywords : Nutrition; apparent digestibility coefficient; phytic acid; fish.

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