Schlüsselwort: Microorganisms

The use of dietary lignocellulose in poultry has been described in only few studies and with inconsistent effects on animal performance, nutrient digestibility and the composition of the intestinal microbiota. The aim of this study was to investigate the influence of higher dosages of dietary lignocellulose in isoenergetically and isonitrogenically designed diets on zootechnical, digestive and microbiological parameters. For this purpose, 59 male chickens of a slow-growing poultry cross-breeding population (WL77 - White Leghorn and NHI - New Hampshire) were divided into three experimental groups and were fed a diet containing 0.8, 5 and 10 % lignocellulose (ARBOCEL® RC Fine) over a period of eight weeks. The feeding trial was divided into a 5-week adaptation phase and a 23-day trial phase. Feed and water were continuously available ad libitum. Zootechnical parameters were recorded weekly and digesta samples from ileum and caecum were taken in the 13th week. Additionally, excrements were collected daily over the last 12 days of the experimental period. The resulting data included not only the determination of the apparent precaecal digestibility of crude protein and the apparent total digestibility of crude fat and organic matter, but also analyses of bacterial metabolites and the composition and metabolic activity of selected bacterial clusters. Statistical evaluation of the results was performed by means of single factor analysis of variance or the Kruskal-Wallis test. An influence of the diets used on the performance of the animals could not be determined. Neither the live mass, live mass gain, feed consumption nor feed expenditure showed changes between the experimental groups. The apparent precaecal digestibility of the crude protein was significantly decreased with 10 % supplemented lignocellulose compared to the experimental group with 0.8 and 5 %. The values of the apparent total digestibility of crude fat showed no changes with increasing contents of lignocellulose in the ration. Significant differences between all three experimental groups were documented in the apparent total digestibility of the organic mass. This parameter decreased with increasing supplements of lignocellulose in the diet. There were no group differences between dry matter contents of the excrements observed. A comparison of the bacterial metabolites in the caecal digesta showed a decrease of the analysed concentrations with increasing content of dietary lignocellulose. The most significant changes in concentration were observed in the experimental group with 10 % lignocellulose. Significant effects on the composition and metabolic activity of the bacterial microbiota were detected in the quantification of the Escherichia/Hafnia/Shigella cluster. With increasing concentration of lignocellulose the measured cell numbers in the caecal digesta decreased. The also decreased values of the determined rRNA copies described a directed trend and additionally indicated a reduced metabolic activity. In conclusion, the results of the present study show that higher concentrations of lignocellulose can influence the apparent precaecal digestibility of protein, the microbial metabolites in the digesta and the composition and activity of the bacterial microbiome. In addition, lignocellulose could have an impact on potential pathogens in the intestine, which should be investigated in further studies.