Influence of a specific amino acid pattern in the diet on the course of an experimental Campylobacter jejuni infection in broilers.

Campylobacter jejuni (C. jejuni) is one of the most important zoonotic pathogens worldwide. In Europe, the majority of the cases are caused by consuming contaminated poultry meat. The objective of the present study was to investigate potential effects of different crude protein levels in complete diets for broilers on infection dynamics of C. jejuni after experimental infection. In total, 300 commercial broilers line Ross 308 were divided into 4 different groups, including 5 replications of 15 chickens each. The chickens were fed a conventional diet (212 g CP/kg DM) and a protein-reduced test diet (190 g CP/kg DM) supplemented with essential amino acids. This resulted simultaneously in lower amino-acid concentrations preferentially utilized by C. jejuni, such as aspartate, glutamate, proline, and serine. One group of each feeding concept was infected artificially with C. jejuni at day 21 by applying an oral C. jejuni inoculum containing 4.17 ± 0.09 log10 cfu of C. jejuni to 3 of 15 chickens, called "seeders." Feeding the test diet resulted in a significant reduction (P < 0.001) in CP intake (31.5 ± 1.20 g CP/broiler/day and 27.7 ± 0.71 g CP/broiler/day, respectively), a significant decrease (P < 0.05) in crude mucin in excreta (55.7 ± 8.23 g/kg DM and 51.9 ± 7.62 g/kg DM, respectively), and in goblet cell number in cecal crypts (P < 0.05; 15.1 ± 5.71 vs. 13.6 ± 5.91 goblet cells/crypt). In groups receiving the test diet, the excretion of C. jejuni was significantly reduced in seeders by 1.9 log10 cfu/g excreta at day 23 (3.38a ± 2.55 vs. 1.47b ± 2.20; P = 0.033). At day 25, prevalence of C. jejuni in cloacal swabs amounted to 53.3% in the group fed the test diet and 75.7% in the control group, respectively (P < 0.05). In summary, a definite amino acid pattern in the broiler diets could contribute to a development of an effective feeding strategy to reduce the prevalence of C. jejuni infection in chickens (Patent No 17187659.2-1106).

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

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.

Effects of a carbohydrase complex added in different inclusion rates in feeds for broilers on growth performance, digesta viscosity and foot pad health.

Foot pad dermatitis (FPD) is a widespread disease in poultry and important for economic and animal welfare reasons. It is well recognized that using non-starch polysaccharide (NSP)-degrading enzymes can affect excreta/litter quality (not only in terms of moisture content but also regarding water evaporation) at high stocking densities and might help to prevent FPD and further negative effects of NSP. This study aimed to evaluate effects of a carbohydrase complex (CC) in different dietary inclusion rates on performance, digesta viscosity and foot pad health in broilers from 9 to 37 days of life. In total, 240 broilers were divided into 12 floor pens of 20 birds and received one of four different experimental diets. The four wheat- and soyabean meal-based diets only differed in the inclusion rate of CC: 0%, 50%, 100% and 500% of the recommended dose of CC (Endo-1,4-ß-xylanase and Endo-1,3(4)-ß-glucanase; 50 g/t). The addition of CC led to a significant decrease of digesta viscosity in the proximal small intestine, a tendency of improved feed conversion ratio, and significantly favoured FPD-scores (Treatment 2). At the higher tested inclusion rate of CC (500% of recommended dose), the FPD score was worser than in the treatments with 50% and 100% of the recommended enzyme dosage. No improvements among treatments were observed in terms of body weight and dry matter content of excreta and litter at the end of trial. The low positive effects on foot pad health in this study were presumably associated with the low NSP content in the experimental diets (soluble arabinoxylans: 7.38 g/kg as fed). In conclusion, the addition of the evaluated CC reduced digesta viscosity. An improvement of foot pad health could only be seen in the treatment with 50% of the recommended enzyme dosage in the diet.