Mitigating the Spread and Translocation of Salmonella Enteritidis in Experimentally Infected Broilers under the Influence of Different Flooring Housing Systems and Feed Particle Sizes.

This study aimed to evaluate the influences of different flooring designs and feed particle sizes on the spread of Salmonella (S.) in broiler chickens. Birds (n = 480) were allocated to four different housing systems (fully littered with and without floor heating, partially and fully slatted flooring with sand bath) and two dietary treatments (finely and coarsely ground diets) in 24 boxes. Two broilers per box were experimentally infected with S. Enteritidis (8.00 log10 CFU/bird) at d 17. Salmonella prevalence in caecal contents and the liver was highest in broilers housed on fully slatted floor until d 36/37 (88.1% and 91.5%, respectively), and lowest in litter flooring (caecal content 64.4%) and litter flooring with floor heating (liver 61.7%). In turn, broilers on littered flooring expressed the lowest Salmonella counts in caecal content at d 36/37 (2.21 ± 1.75 log10 CFU/g), partial slatted flooring the highest (3.76 ± 1.46 log10 CFU/g). The mean Salmonella count in the caecal content was significantly lower for birds fed a coarsely ground diet (0.96 and 1.94 log10 CFU/g) than a finely ground diet (5.07 and 3.34 log10 CFU/g) at d 23 and d 36/37, respectively (p < 0.0001). Slatted flooring with a sand bath did not show advantages in terms of Salmonella reduction, whereas the coarsely ground diet markedly reduced the spread of Salmonella.

The Effects of Feed Particle Size and Floor Type on the Growth Performance, GIT Development, and Pododermatitis in Broiler Chickens.

The aim of the present study was to evaluate the effects of feed particle size and flooring designs on organ traits, performance and pododermatitis in broilers. A total of 480 broilers (Ross 308) of both sexes were randomly assigned to two feeding groups (finely or coarsely ground pelleted diets; with addition of 5% to 10% intact wheat in coarsely diets) and four different housing systems (litter; litter with floor heating; partially or fully slatted floor) with three subgroups each. A coarse diet increased the final gizzard and pancreas weights (p < 0.001) while decreasing the risk of Isthmus gastrici dilatation compared to a fine diet (p < 0.001). Broilers fed a coarse diet displayed an increased final body weight (p = 0.023) and led to a favourable feed conversion ratio. Final body weight was the highest (p < 0.001) for birds housed on partially or fully slatted floor. Housing birds on litter with floor heating showed the lowest pododermatitis scoring (p < 0.001). It seems to be favourable to use coarse diets for organ development, whereas slatted floors seem to foster enlargement of the Isthmus gastrici. Increasing growth performance was possible both when using coarse diets or slatted floors.

Influence of Different Methionine Sources on Performance and Slaughter Characteristics of Broilers.

Sustainably produced poultry meat with consideration of animal health poses a challenge for broiler production. Low protein diets with high amounts of synthetic amino acids (AAs) like methionine (Met) are the consequence. In a five-week feeding trial, 360 broilers (Ross 308) assigned to four feeding groups were offered protein-reduced complete diets (starter: 20% crude protein (CP); grower: 18.5% CP; finisher: 17.5% CP), supplemented with essential AAs. The "MHA" group received DL-2-hydroxy-4-(methylthio) butanoic acid (DL-HMTBA; trade name: MHA®), groups "L" and "DL" the respective Met source in equivalent concentrations each exceeding the nutritional recommendations. "R-MHA" ("R" for "reduced") received the minimum required level (using MHA as Met source). Performance exceeded performance goals without differences between the groups. The average feed conversion ratio (FCR) amounted to 1.35. The carcass/body weight ratio of R-MHA was significantly lower (0.782) compared to DL (0.808) and L (0.809). Breast meat of R-MHA contained significantly more fat (144 g/kg dry matter (DM)) compared to L (104 g/kg DM) and significantly lower CP content (R-MHA: 838 g/kg DM; L: 875 g/kg DM). The results indicated possible improvement in slaughter yield by protein-reduced diets supplemented with L-Met, thus recommending further research focusing on the Met influence.

Influence of lauric acid on the susceptibility of chickens to an experimental Campylobacter jejuni colonisation.

Among the organic acids, lauric acid has shown a high level of in vitro activity against Campylobacter jejuni. The prevalence and intensity of C. jejuni excretion at slaughter often becomes lower with increasing age. In higher-aged broilers on organic farms which often use other breeds, in turn, the prevalence of C. jejuni is sometimes higher at slaughter. The question then arises as to whether a diet with higher lauric acid concentrations, the age alone or the genetic breed might have an effect in the spread and intensity of an experimental C. jejuni infection in vivo. Therefore, two complete diets with or without 2% lauric acid from palm kernel fatty acids were offered to 450 chickens (ten subgroups à 15 birds, repetitions: n = 3) of two broiler and two layer breeds (Ross 308, Hubbard JA 757, Lohmann Dual and Lohmann Brown-Classic). All breeds were reared for 42 days, Lohmann Brown-Classic also for about 98 days. Twenty-one days before dissection, three seeder birds per subgroup were orally infected with a 1 mL inoculum of C. jejuni (4.46±0.35 log10 CFU/mL). Qualitative detection of C. jejuni in cloacal swabs was performed at days 2, 4, 7, 14 after inoculation and at dissection in all birds. Quantitative detection was performed on excreta samples of seeder birds at days 2, 11 and 17 after experimental challenge and on caecal samples of all birds at dissection. Two days after experimental inoculation, C. jejuni prevalence was higher in control birds without lauric acid supplementation (48.9% vs. 39.6%; P = 0.0462). Depending on age, two days after inoculation the C. jejuni prevalence in young Lohmann Brown-Classic chickens was significantly lower (37.8% vs. 61.1%) whereas at dissection it was higher (99% vs. 67%). At day 2 after inoculation C. jejuni counts in the excreta of young Lohmann Brown-Classic were lower in comparison to those in old ones (log10 CFU/g: 3.30±2.68 vs. 5.24±1.56). Eleven (log10 CFU/g: 5.14±1.13 vs. 4.16±0.82) and 17 days after inoculatioin (log10 CFU/g: 3.77±2.02 vs. 1.72±1.87) it was the reverse situation. At dissection, the carriage of C. jejuni in caecal content was higher in younger than in older birds (log10 CFU/g: 8.57±0.46 vs. 6.66±1.43). An effect of genetic breed on C. jejuni prevalence was seen at dissection, this being lowest in Lohmann Dual chickens (91% vs. 98.9% in other breeds). At d 17 after challenge, C. jejuni counts in the excreta of young Lohmann Brown-Classic were lower in comparison to Ross 308 and Hubbard JA 757 (log10 CFU/g: 3.77±2.02 vs. 5.21±0.85 and 5.62±0.90). Lohmann Dual chickens showed an intermediary excretion, this being only significant lower compared to Hubbard JA 757 (log10 CFU/g: 4.31±0.89). In summary, the effect of lauric acid is limited to the initial phase after experimental inoculation. A higher age at infection seems to lead to a more rapid limitation of the infection. The excretion of C. jejuni appears to decrease more rapidly in layer breeds than in broiler lines after experimental inoculation.

Individual differences in the phosphorus metabolism of fattening bulls--testing effects of crude fibre and calcium chloride in the diet.

Urolithiasis due to struvite concrements occurs in fattening cattle, but only in 1-5% of a herd, in spite of identical nutrient supply. Developing dietetic measures for these cattle was the primary aim of this study. The feeding experiments were focused on the general effects of varying the crude fibre supply and adding CaCl2 as a urine acidifier, especially concerning individual reactions to the different diets. Five standard balance trials were performed with three fattening bulls. The crude fibre content in the ration varied between 14.8% and 24.0% DM. In two trials, coated CaCl2 was fed (per day 20 g/100 kg BW). Influences on the macro mineral metabolism and the acid-base-balance were investigated. Unexpectedly, the crude fibre content had no significant effect on the renal P excretion, but individual differences occurred concerning digestibility, renal excretion and serum concentration of P: one bull constantly showed significantly higher values. Adding CaCl2 resulted in reduced renal P excretion and pH values of the urine (< 6.5). Thus, using CaCl2 might be a beneficial dietetic measure for preventing struvite. The huge individual differences in the P metabolism could be linked to genetically-based variations, as known for sheep.