Response of turkeys fed wheat-barley-rye based diets to xylanase supplementation

The objective of this study was to evaluate the effect of xylanase on performance, nitrogen corrected apparent metabolizable energy (AMEn), relative gastrointestinal (GIT) weights, caecal fermentation and microbiota profile of turkeys fed wheat-barley-rye based diets. Four hundred eighty female Hybrid Converter turkey poults (1-day-old) were placed in one of two experimental treatments: a control diet (CTR) formulated to be marginally deficient in metabolizable energy, and the same diet supplemented with 16,000 BXU/kg of xylanase (XYL). Treatments had fifteen replicate pens per diet, with 16 birds each. Feed was supplied in four phases of three weeks per phase. On d 1, 21, 42, 63 and 84 body weight was measured, and feed intake (FI) recorded. Body weight gain (BWG) and feed conversion ratio (FCR) were then calculated. On d 84 the last day of the study excreta samples were collected to determine AMEn. The profile of volatile fatty acids (VFA), lactic acid and branched-chain fatty acids (BCFA) in addition to the microbial community structure by the percentage of guanine plus cytosine (G + C) profile method in the caecal digesta were analysed on d 84. Statistical comparisons were performed using one-way ANOVA (JMP Pro 12). Xylanase supplementation over the 12 week study improved FCR (P < 0.01) from 2.09 to 2.02. Birds supplemented with xylanase tended on average to be 163 g heavier than the control birds, with no significant effects observed on FI. The AMEn in birds fed the XYL diets was numerically greater than that observed for CTR birds. No differences were found between treatments neither in VFA, lactic acid, BCFA concentrations nor in relative GIT weights. The percentage of G + C at 35-43, 50-56 and 66-70 regions differed significantly, indicating a shift in the microbial community structure between CTR and XYL-fed birds. Supplementation of turkey diets with xylanase improved performance, probably due to a better utilization of energy and the provision of oligosaccharides which specifically encourage proliferation of specific populations of bacteria in the caeca.