ABSTRACT Pasteurella multocida causes fowl cholera which is an economically important disease in poultry industries around the world. In this study, we analyzed the capsular genotype, lipopolysaccharide (LPS) genotype, virulence-associated genes (VAGs) patterns, antimicrobial resistance and genetic diversity in a total of 9 P. multocida isolates from poultry with fowl cholera between 2014 and 2019 in Korea. When combining the capsular types with the LPS genotypes, two isolates of the 9 isolates were A:L3, and the others were non-typeable (NT): L3. Of the 23 VAGs, all the isolates harbored ptfA, fimA, hsf-1, hsf-2, pfhA, exbB, exbD, tonB, hgbA, hgbB, fur, sodA, sodC, pmHAS, ompA, ompH, oma87, plpB, psl, and nanH, whereas toxA gene was not detected in any of the 9 isolates. In addition, among the 11 antimicrobials, most of the isolates except for one isolate resistant to florfenicol, exhibited susceptibility to all the antimicrobials. Multi-locus sequence typing (MLST) analysis revealed 5 different sequence types (ST): ST8, ST351, ST352, ST353, and ST368. The ST351, ST352, ST353, and ST368 were identified for the first time in this study, and ST352 and ST353 isolates were largely prevalent nationwide. These STs isolates should be monitored continuously because in some cases, ST352 and ST353 isolates demonstrated high mortality rates. Although only limited numbers of isolates have been analyzed, our findings provide overall characteristics and epidemiological information of the P. multocida strains recently prevalent in Korea.

ABSTRACT In total, 216 Hy-Line brown laying hens (40-week-old), were used in a 5-week experiment to evaluate the effects of ionized or chelated water-soluble mineral mixture supplementation on live performance, nutrient digestibility, blood characteristics, egg quality, and excreta microbiota. Layers were randomly assigned to one of three dietary treatments with 12 replicates of six adjacent cages each. The dietary treatments consisted of: 1) CON (basal diet + normal tap water), 2) T1 (CON+0.5% ionized mineral mixture in tap water, pH 3.0); and 3) T2 (CON+ 0.5% chelated mineral mixture in tap water, pH 3.0). Egg production tended to increase in week 1, week 3 and week 4 in the birds supplemented with T1 and T2 diet compared with CON. Moreover, the dietary supplementation of water-soluble mineral mixture improved (p=0.02) eggshell thickness in week 4 and tended to improve in week 5 of the experimental period in T2 hens compared with CON. The layers fed the T1 diet presented higher (p<0.05) Ca digestibility than CON hens, while the T2 diet promoted a numerical increase in Ca digestibility. Blood calcium concentration increased (p<0.05) with T1 and T2 treatments compared with CON. The laying hens fed the T1 and T2 diets tended to present lower Salmonella and E. coli counts isolated from excreta compared with CON. In conclusion, ionized and chelated mineral mixtures had a positive impact on production performance and eggshell quality, improved Ca digestibility and blood Ca level.