Nutritional value of field bean-containing diets for broilers without and with phytase, xylanase and protease enzymes, alone or in a combination.

Abstract

The effects of exogenous phytase (PHY), xylanase (XYL) and protease (PRO) alone and in a combination, when supplemented to diets based on three field bean cultivar samples with different chemical composition, on dietary metabolisable energy (ME), nutrient digestibility, gastrointestinal tract (GIT) development, feed intake (FI), weigh gain (WG) and feed conversion ratio (FCR) were studied. Diets based on beans with lower phytic acid and fibre content had higher ME, fat (p < 0.05) and dry matter retention (p < 0.001) coefficients, which coupled with greater feed efficiency, e.g. reduced FCR (p < 0.001). Dietary PHY alone reduced FCR (p < 0.001) and XYL alone improved dietary ME (p < 0.05). An interaction (p < 0.05) between enzymes regarding FI and WG occurs, but PHY seems to be the main contributor to improved performance. There was an interaction (p < 0.05) between bean cultivars and enzymes regarding nitrogen retention (NR) as PHY produced a greater coefficient when supplemented with a low phytate diet. The overall weight of the total GIT was not changed by the enzymes or bean cultivars (p > 0.05). The changes observed in different GIT segments are unlikely to have biological significance.