Protective effects of fowl-origin cadmium-tolerant lactobacillus against sub-chronic cadmium-induced toxicity in chickens.

Cadmium (Cd) directly endangers poultry health and indirectly causes harm to human health by food chain. Numerous studies have focused on removing Cd using lactic acid bacteria (LAB). However, there is still a lack of in vivo studies to validate whether Cd can be absorbed successfully by LAB to alleviate Cd toxicity. Here, we aimed to isolated and screened poultry-derived Cd-tolerant LAB with the strongest adsorption capacity in vitro and investigate the protective effect of which on sub-chronic Cd toxicity in chickens. First, nine Cd-tolerant LAB strains were selected preliminarily by isolating, screening, and identifying from poultry farms. Next, four strains with the strongest adsorption capacity were used to explore the influence of different physical and chemical factors on the ability of LAB to adsorb Cd as well as its probiotic properties in terms of acid tolerance, bile salt tolerance, drug resistance, and antibacterial effects. Resultantly, the CLF9-1 strain with the best comprehensive ability was selected for further animal protection test. The Cd-tolerant LAB treatment promoted the growth performance of chickens and reduced the Cd-elevated liver and kidney coefficients. Moreover, Cd-induced liver, kidney, and duodenum injuries were alleviated significantly by high-dose LAB treatment. Furthermore, LAB treatment also increased the elimination of Cd in feces and markedly reduced the Cd buildup in the liver and kidney. In summary, these findings determine that screened Cd-tolerant LAB strain exerts a protective effect on chickens against sub-chronic cadmium poisoning, thus providing an essential guideline for the public health and safety of livestock and poultry.

Expression of the Campylobacter jejuni FliD protein and its reaction to chicken sera.

Campylobacter is a leading causative pathogen of acute bacterial gastroenteritis among humans. Contaminated chicken products are regarded as major sources of human infection. The flagellar capping protein (FliD), which plays important roles in colonization and adhesion to the mucosal surface of chicken ceca, is conserved among Campylobacter jejuni strains. In this study, the recombinant C. jejuni FliD protein was expressed, purified and used as a coated protein to examine the prevalence of C. jejuni antibodies in chickens. The anti-FliD antibody was prevalent among chicken serum samples taken from different farms in the diverse regions of Jiangsu province by using enzyme-linked immunosorbent assay. The Campylobacter antibody was present in culture-negative chickens. No strong dose-response relationships were observed between serum FliD antibody levels and Campylobacter cultural status. These results provide a basis for further evaluating FliD as a vaccine candidate for broiler chickens or for examining host-C. jejuni interactions, with implications for improving food safety.

Rapid and sensitive detection of Listeria monocytogenes by loop-mediated isothermal amplification.

Loop-mediated isothermal amplification (LAMP) was designed for detection of Listeria monocytogenes, which is an important food-borne kind of pathogenic bacteria causing human and animal disease. The primers set for the hlyA gene consist of six primers targeting eight regions on specific gene. The LAMP assay could be performed within 40 min at 65°C in a water bath. Amplification products were visualized by calcein and manganous ion and agarose gel electrophoresis. Sensitivity of the LAMP assay for detection of L. monocytogenes in pure cultures was 2.0 CFU per reaction. The LAMP assay was 100-fold higher sensitive than that of the conventional PCR assay. Taking this way, 60 chicken samples were investigated for L. monocytogenes. The accuracy of LAMP was shown to be 100% when compared to the "gold standard" culture-biotechnical, while the PCR assay failed to detect L. monocytogenes in two of the positive samples. It is shown that LAMP assay can be used as a sensitive, rapid, and simple detection tool for the detection of L. monocytogenes and will facilitate the surveillance for contamination of L. monocytogenes in food.