Estimating the apparent total tract digestibility at different ages in rabbits by using faecal enzyme activities and in vitro digestibility on diets as predictors

Abstract

The determination of apparent digestibility by non-invasive techniques such as prediction equation is an efficient technique for appraising the gastrointestinal performance and some indication of health status in rabbits. Therefore, faecal enzyme activities and in vitro digestibility by using crude enzyme extract from individual (CEi) rabbits at 92-days-old, pooled CEi (CEp), or commercial enzyme (CM) as independent variables was investigated, in order to estimate apparent digestibility in rabbits at different ages. Apparent total tract digestibility and faecal samples for enzyme activities at different age of twelve New Zealand white rabbits was calculated and collected. CEi from different digestive organs were taken from slaughtered 92-day-old rabbits. Based on multiple linear regression models, the percentage of in vitro digestibility on dry matter (DM) and organic matter (OM) with CEi fit well relative to using CM to estimate apparent digestibility on DM (DMd; R2 = 0.49 vs 0.17, respectively) and OM (OMd; R2 = 0.51 vs 0.49, respectively). A low determination coefficient for predicting DMd and OMd was found when using faecal enzyme activity with or without in vitro digestibility data. However, the use of CEp as independent variables provided a higher determination coefficient than using CM. Moreover, the equation which was run for in vitro digestibility on OM using CEp, faecal protease and cellulase activities, was statistically significant in terms of predicting apparent digestibility on crude protein (R2 = 0.72, SEE = 7.05, P = 0.03). Therefore, these parameters can be used as independent variables to estimate apparent digestibility to individual rabbit to reveal current digestive efficiency