兽医科技

Rabbit meat is a rich source of protein with low fat and cholesterol contents making it a healthy meat source. Listeria monocytogenes is one of foodborne pathogens that can cause a serious disease named listeriosis in humans. This study firstly investigated the prevalence of Listeria spp., particularly Listeria monocytogenes in rabbit meat and offal. Secondly, the expression of virulence associated genes and the antibiogram of the identified Listeria monocytogenes were further examined. The achieved results revealed that Listeria spp. was isolated from rabbit thigh muscles, shoulder muscles, loin, liver and kidneys at 25%, 15%, 10%, 15% and 5%, respectively. Five Listeria spp. namely, L. monocytogenes, L. ivanovii, L. innocua, L. welshimeri and L. seeligeri were serologically identified. Multidrug pathogenic L. monocytogenes was particularly isolated from thigh muscles and loin only at 12.5% and 7.5%, respectively. L. monocytogenes isolates showed a complete resistance (100%) to both of kanamycin and neomycin.

Riemerella anatipestifer (RA) is a major bacterial disease affecting the poultry industry worldwide, particularly causing high economic losses in duck farms in Egypt. The objective of this experimental study was firstly to investigate the effects of RA-experimental infection on the morbidity and mortality rates and growth performance in Pekin ducks. Secondly the effects of RA on the transcriptomic expression of the immune related genes (interleukins (IL)1β, 6, 8, 10 and 17A) in the infected ducks were also examined using real time quantitative PCR. Thirdly, the protective effects of Bacillus subtilis (B. subtilis) as a probiotic dietary supplementation against RA infection in ducks were also investigated. The achieved results indicated that the mortality rate in RA-experimentally infected group was 80% and this percentage was reduced to 20% when birds received probiotics in their diet before challenge with RA. Furthermore, RA infection reduced the average feed intake, average body gain with poor average feed conversion ratio, while dietary supplementation of probiotics to ducks ’ feed significantly improved growth performance parameters. RA modulated the gene expression of the immune related genes, however, probiotics significantly upregulated mRNA expressions of the examined cytokines as a mechanism for the protective roles of probiotics against RA infection in ducks. Therefore, it is highly recommended to use probiotics dietary supplementation in duck farms in order to improve the growth performance and reduce the disease burden.

There is currently a world trend to reduce using of antibiotics in poultry industry and replacing it by natural alternatives such as probiotics to obtain healthy and antibiotic-free chicken meat. Therefore, this study evaluated firstly the microbial status of chicken carcasses in Dakahliya Governorate, Egypt. Then, the effect of using probiotics before slaughtering by 48 hours on the microbial status of chicken carcasses was experimentally investigated. Microbiological examination in this study included general microbial indicators (Aerobic plate count, Enterobacteriaceae count and Most Probable Number of coliforms), isolation and identification of Campylobacter spp. In addition, multiplex PCR was used to detect the virulence-associated genes of Campylobacter jejuni including cdtA, cdtB and cdtC toxin-producing genes. The achieved results revealed high microbial load of both commercial and untreated chicken carcasses compared with the probiotics-treated carcasses, which showed significant improvement, in terms of the microbiological quality of the chicken carcasses.