Influence of different protein sources in the broiler diet on the presence of Campylobacter spp. in excreta and caecal content

Abstract

The aim of the present study was to examine possible effects of a different protein supply on the presence of Campylobacter in excreta and caecal content of broiler chickens. Therefore, 220 one-day-old chickens were fed five different diets in the experimental period (day 8 onwards). In the control group (CON; n = 3 boxes), a soya bean-based industrially produced complete diet containing 5-10% whole wheat and coccidiostats was fed, whereas in the remaining groups, four own-made complete diets with four protein sources and combinations (4 × 2 boxes; soya bean meal-based diet = SBM; rapeseed meal-containing diet = RSM; haemoglobin meal-containing diet = HGP; algae-containing diet = ALG) were offered. During the 6-week trial period, data concerning performance parameters, excreta and litter characteristics and microbiological analysis of excreta and caecal content at dissection were collected. The qualitative bacteriological investigation was based on the EN ISO 10272-1:2006, taken from the official collection of analysis methods in accordance with § 64 LFBG. For quantitative bacteriological tests, a 10-fold dilution series was made followed by culture-based quantification methods on approved selective media in duplicate. Comparing the results of the final dissection (day 44/45), nearly all samples of animals receiving the own-made complete diet were Campylobacter positive in the caecal content, whereas only seven of fifteen samples were positive in the CON group. With regard to the CFU in the caecal content, the counts of Campylobacter were significantly lower for animals fed the commercial diet (2.47 ± 3.06 vs. 7.36 ± 0.66 log₁₀ CFU/g). When only the positive animals were evaluated, significant differences were also found between the CON group and the total of the other groups (5.30 ± 2.08 vs. 7.54 ± 1.70 log₁₀ CFU/g). Although significant differences were seen in the results, no final recommendation can be given how to create a diet to reduce an infection with Campylobacter.

Keywords: Campylobacter spp.; chicken; diet; excreta quality; protein sources.