Dietary Supplementation throughout Life with Non-Digestible Oligosaccharides and/or n-3 Poly-Unsaturated Fatty Acids in Healthy Mice Modulates the Gut–Immune System–Brain Axis

The composition and activity of the intestinal microbial community structures can be beneficially modulated by nutritional components such as non-digestible oligosaccharides and omega-3 poly-unsaturated fatty acids (n-3 PUFAs). These components affect immune function, brain development and behaviour. We investigated the additive effect of a dietary combination of scGOS:lcFOS and n-3 PUFAs on caecal content microbial community structures and development of the immune system, brain and behaviour from day of birth to early adulthood in healthy mice. Male BALB/cByJ mice received a control or enriched diet with a combination of scGOS:lcFOS (9:1) and 6% tuna oil (n-3 PUFAs) or individually scGOS:lcFOS (9:1) or 6% tuna oil (n-3 PUFAs). Behaviour, caecal content microbiota composition, short-chain fatty acid levels, brain monoamine levels, enterochromaffin cells and immune parameters in the mesenteric lymph nodes (MLN) and spleen were assessed. Caecal content microbial community structures displayed differences between the control and dietary groups, and between the dietary groups. Compared to control diet, the scGOS:lcFOS and combination diets increased caecal saccharolytic fermentation activity. The diets enhanced the number of enterochromaffin cells. The combination diet had no effects on the immune cells. Although the dietary effect on behaviour was limited, serotonin and serotonin metabolite levels in the amygdala were increased in the combination diet group. The combination and individual interventions affected caecal content microbial profiles, but had limited effects on behaviour and the immune system. No apparent additive effect was observed when scGOS:lcFOS and n-3 PUFAs were combined. The results suggest that scGOS:lcFOS and n-3 PUFAs together create a balance—the best of both in a healthy host.

Prevalence and antibiotic resistance of Escherichia coli O157:H7 in beef at a commercial slaughterhouse in Moro, Kwara State, Nigeria

Background. Gastroenteritis due to foodborne disease is a leading cause of death in developing countries. In Nigeria, there is an increasing demand for beef. Yet, there is no surveillance for Escherichia coli O157:H7 contamination of raw beef and little is known about the carriage of this pathogen in Nigeria’s livestock. Methods. A total of 415 samples, including 180 cow carcass swabs, 180 caecal content samples, 16 water samples, 25 hand swabs and 14 knife swabs were collected at a large abattoir in the Moro region of Kwara State, Nigeria. The samples were enriched in modified tryptone broth containing novobiocine, and plated onto Sorbitol–MacConkey agar (Oxoid SR0172E) supplemented with 0.05 mg l−1 cefixime and 2.5 mg l−1 potassium tellurite (Oxoid) (CT-SMAC). Indole-producing isolates were confirmed serologically by serotyping with antisera specific for the O157 and H7 antigens. The E. coli O157:H7 isolates were further tested for their susceptibility to antibiotic agents using the disc diffusion method. Commercially available Gram-negative multi-discs (Oxoid) comprising nitrofurantoin (30 µg), ampicillin (5 µg), ceftazidime (30 µg), gentamicin (10 µg), ciprofloxacin (5 µg), augmentin (30 µg), ofloxacin (5 µg) and cefuroxime (30 µg) were tested. Results. Overall, 16 (3.9 %) samples were contaminated with E. coli O157:H7, of which 10 (5.6 %) were isolated from carcass swabs, 4 (2.2 %) from caecal content samples and 2 (12.5 %) from water. All isolates were multidrug-resistant (MDR), with resistance to ampicillin, ceftazidime and cefuroxime being the most common. Conclusion. This study provides evidence to suggest that E. coli O157:H7 exists in the beef production chain. The pathogen reveals a high frequency of multidrug resistance, suggesting that consumers and handlers of such meat are at risk of contracting antibiotic-resistant E. coli O157:H7-associated foodborne disease. Routine monitoring of antibiotic resistance is critical to uncovering novel therapeutic strategies that will help inform clinical practice guidelines.

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.

Effects of dietary supplementation of alfalfa meal and rice bran on growth performance, carcass characteristics and intestinal microbiota in broilers

The composition of gastrointestinal tract microbiota can be changed by dietary manipulation, to prevent gut health issues and to promote animal performance. This study was conducted to investigate the effects of rice bran and alfalfa meal on growth performance and intestinal microbiota in broilers. A total of 252 Cobb 500 broilers, aged 14 days, were randomly assigned into 3 groups: control (CON), 5 % rice bran (RB), 5 % alfalfa meal (AM), and housed in an environment-controlled hall 42 days. Throughout the experimental period, grow performance parameters were monitored and at the end relative weights of internal organs were measured. Samples of intestinal content were collected for bacteriological determinations. Feed intake, daily weight gain and viability were not significantly affected by the dietary supplements. Alfalfa meal and rice bran decreased the populations of Escherichia coli and staphylococci in small intestine content, and Enterobacteriaceae, Escherichia coli and staphylococci in caecal content of broilers. The count of lactobacilli in both small intestine and caecal content registered a significantly increase in experimental groups, compared to CON group. Supplementation of diets with rice bran and alfalfa meal tended to increase the population of beneficial bacteria and inhibit the potential pathogens.

Can animal welfare have an impact on food safety? A study in the poultry production chain

Background Animal welfare is a major issue in the production of food of animal origin. A project funded by the Italian Ministry of Health was carried out in order to collect scientific evidence that animal welfare is not only an ethical issue, but should also be related to food safety. Methods The project was carried out along an Italian integrated poultry production chain. Animal welfare was measured at farm in 13 broiler chicken batches, including 2 organic, using Welfare Quality®, an animal- and resource-based internationally recognised protocol. Samples for the detection and enumeration of Campylobacter, Salmonella and Listeria monocytogenes were taken at different levels, from the live animal (faeces at farm and after transport) to the end product (caecal content and carcass skin at slaughterhouse), with a total of 2,080 samples. Strains were deeply characterised (serotyping, PFGE). Results Higher welfare scores were reported in organic batches. Transports to the slaughterhouse longer than 1 hour were associated to increased Campylobacter prevalence. Significantly lower Campylobacter concentrations both in faeces and carcass (P &lt; 0.05) were reported in organic batches. Low-welfare batches showed higher prevalence of Salmonella, with statistically significant difference compared to high-welfare batches (43.6% versus 2.9% in carcass; 19.3% versus 0% in caecal content; P &lt; 0.00001). L. monocytogenes was never found in faeces, in contrast with high prevalence in carcases (up to 72.5%) with undistinguishable genetic profiles recurrent in different batches after long time (up to 18 months). Conclusions Our results support the hypothesis that poultry meat contamination is influenced by the welfare or stress which broilers experience during their life. Longer transports enhance Campylobacter prevalence. L. monocytogenes in poultry meat should not be linked to increased stress but rather to persistent contamination in the slaughterhouse processing environment. Key messages “High-welfare” broiler chicken batches show lower Campylobacter and Salmonella contamination compared to “Low-welfare” batches. Microbiological safety of poultry meat can be improved by the application of high animal welfare standards at farm and during transport.

Prevalence and Antibiotic Resistance Pattern of Salmonella Isolated from Caecal Contents of Exotic Chicken in Debre Zeit and Modjo, Ethiopia

A cross-sectional study was conducted between December, 2013, and May, 2014, to determine the prevalence and antibiotic resistance feature of Salmonella isolated from broilers slaughtered in Debre Zeit and Modjo towns, Ethiopia. A total of 384 caecal content samples were collected for microbiological examination following the standard techniques and procedures outlined by the International Organization for Standardization to isolate Salmonella. The sensitivity of the isolates subjected to nine antimicrobials was tested by the Kirby–Bauer disk diffusion method. The overall prevalence of Salmonella was 14.6%, and its occurrence differ significantly by farm (p<0.05). The occurrence of the bacteria was not statistically different in the midland (15.2%) and lowland (13.3%) (p>0.05) and between males (13.5%) and females (15.6) (p>0.05). Of the 50 isolates, 48 were resistant to at least one drug. Multidrug resistance was recorded in 43 (86.0%) of the isolates. The study demonstrated considerable prevalence and high antimicrobial resistant Salmonella in exotic chicken and indicates the potential importance of chickens as source of foodborne salmonellosis and multiple antimicrobial resistance of Salmonella. Improving the hygienic practice of farms could help to reduce the occurrence of Salmonella in farms. Further studies are needed to describe the risk factors associated with the emergence of drug-resistant Salmonella in chicken.

Limited overlap in RNA virome composition among rabbits and their ectoparasites reveals barriers to virus transmission

Ectoparasites play an important role in virus transmission among vertebrates. However, little is known about the extent and composition of viruses that pass between invertebrates and vertebrates. In Australia, flies and fleas support the mechanical transmission of viral biological controls against wild rabbits - rabbit haemorrhagic disease virus (RHDV) and myxoma virus. We compared virome structure and composition in rabbits and these associated ectoparasites, sequencing total RNA from multiple tissues and gut contents of wild rabbits, fleas collected from these rabbits, and flies trapped sympatrically. Meta-transcriptomic analyses identified 50 novel viruses from multiple RNA virus families. Rabbits and their ectoparasites were characterised by markedly different viromes: although viral contigs from six virus families/groups were found in both rabbits and ectoparasites, none were vertebrate-associated. A novel calicivirus and picornavirus detected in rabbit caecal content were vertebrate-specific: the newly detected calicivirus was distinct from known rabbit caliciviruses, while the novel picornavirus clustered with the Sapeloviruses. Several Picobirnaviridae were also identified, falling in diverse phylogenetic positions suggestive of an association with co-infecting bacteria. The remaining viruses found in rabbits, and all those from ectoparasites, were likely associated with invertebrates, plants and co-infecting endosymbionts. While no full genomes of vertebrate-associated viruses were detected in ectoparasites, suggestive of major barriers to biological transmission with active replication, small numbers of reads from rabbit astrovirus, RHDV and other lagoviruses were present in flies. This supports the role of flies in the mechanical transmission of RHDV and implies that they may assist the spread of astroviruses.