Digestibility markers of sheep diets containing hydrolyzed sugarcane-top hay

Abstract

SUMMARY This experiment evaluated the correlation between the estimates of fecal digestibility and dry matter digestibility (DMD) and nutrients obtained using internal (indigestibles dry materiDM, neutral detergent fiber-iNDF, acid detergent fiber-iADF and acid detergent ligniniADL) and external (chromium oxide-Cr2O3, titanium dioxide-TiO2, and purified and enriched lignin from eucalyptus-LIPE®) markers and the values obtained by the total feces collection method. Twenty uncastrated male sheep, with 29.64±5.53 kg average live weight; approximately 12 months old, were kept in metabolic cages and fed diets containing untreated sugarcane-top hay or sugarcane-top hay hydrolyzed with 3 and 6% urea or 1.5 and 3% calcium oxide (CaO). There was a positive correlation (P<.05) between the fecal production estimated by the markers and via total feces collection, with coefficients higher than 90% for iDM, Cr2O3, and TiO2. The DMD and nutrients estimated with the use of markers was positively correlated (P<.05) with that obtained by total feces collection. Coefficients of correlation for digestibility obtained by total collection were higher than those obtained with Cr2O3, but close to those obtained using TiO2. The coefficient of correlation between the digestibility of protein and fiber fraction estimated with iDM and iNDF and that obtained by total collection was higher than 70%. Internal marker iDM and external markers Cr2O3 and TiO2 are effective in estimating fecal production and DMD and nutrients.