Effects of enzymatic treatment and shell content of palm kernel expeller meal on performance, nutrient digestibility, and ileal bacterial population in broiler chickens

Abstract

The objective of this study was to examine the effects of enzymatic treatment and shell content of palm kernel expeller meal (PKE) on the performance, nutrient digestibility, and ileal bacteria population in broiler chickens. Part of the PKE sample was sieved (3 mm) to remove the shell (lower shell PKE) and part was used as is. The primary mannan-oligosaccharides in the experimental diets were determined using HPLC analysis. During the finisher phase, one hundred male broiler chickens (Cobb-500) were fed a control diet or the diets containing 200 g/kg of normal PKE (70 g/kg shell), low shell PKE (30 g/kg shell), enzymatically (cellulase and mannanase) treated PKE, or low shell, enzymatically treated PKE. The DM, CP, and ether extract digestibility coefficients were measured using acid insoluble ash as an insoluble marker. The quantitative rea-time PCR was used to determine the ileal bacteria populations. The enzymatic treatment significantly increased the mannose and also mannan-oligosaccharides content of PKE. Feed intake was not affected by dietary inclusion of PKE. In the birds fed the low shell PKE diet the average daily weight gain was lower and the feed conversion ratio was higher than those in the control and other PKE fed groups. The digestibility coefficients of dry matter and ash were lower in PKE containing diets than the control diet. However, there were no differences in the crude protein and ether extracts digestibility coefficients between the diets containing the enzymatic treated PKE (normal or low shell) and the control diet. The lowest ileal Lactobacilli population was found in the chickens fed the low shell PKE diet. Dietary normal PKE or low shell-enzymatic treated PKE decreased the Escherichia coli population compared to the control diet. The results suggested that PKE could be included up to 200 g/kg in the finisher diet without any apparent adverse effect on performance in broilers; however, any screening practice to reduce the shell content of PKE without enzymatic degradation of β-mannan, decreased its nutritive value.