A gene-detection method based on an enrichment culture broth was developed and used to control an outbreak of Salmonella enterica serovar Dublin (SD) at a dairy farm. The diagnostic performance of this method was evaluated using three DNA extraction approaches: an extraction kit, an automated nucleic acid extractor, and thermal lysis. Automated extractors and extraction kits were the most sensitive to the blood culture broth, while automated extractors and thermal lysis showed the highest sensitivity to fecal enrichment broth. This process required only one to two days, facilitating rapid decision-making regarding control measures. SD was detected in calves and their surrounding environment but not in adult cows. Based on antimicrobial susceptibility testing, SD-positive calves were treated, and contaminated areas were cleaned and disinfected, with continuous monitoring thereafter. Subsequent monitoring showed no additional positive cases, and complete eradication was achieved five months after the initiation of control measures. Overall, the gene-detection method demonstrated greater sensitivity and speed than conventional isolation culture-based methods, facilitating early intervention and effective farm biosecurity management.

Eight broiler chickens with gastrointestinal tract duplication cysts were investigated. In four cases, the duplication cysts were closely attached to the proventriculi of the chickens, and in the remaining four cases, the duplication cyst was closely attached to the ventriculus, ileum, esophagus or duodenum of the individual chicken. Macroscopically, seven of the eight cysts were closely attached to the dorsal surface of the alimentary tract. Histologically, the height of the villous projection formed by the epithelia lining, the number of gland-like tissues in the lamina propria and the thickness of smooth muscular layer were measured for each cyst. The ventricular duplication cyst had tall villous projections and many gland-like tissues, and the cyst contained eosinophilic substances arranged in striated patterns in the lumen. The ileal duplication cyst had moderately tall villous projections and moderately many gland-like tissues. For both cysts, the smooth muscular layer was moderately developed. The results suggest that the former and latter cysts are lined with mucosae similar to the ventricular and intestinal mucosae, respectively. Both cysts are the first reported in chickens. Although the exact pathogenesis for gastrointestinal tract duplication cysts is unclear, the dorsal location of most cysts in the examined cases might suggest that the split notochord syndrome theory proposed regarding human cases is the most likely.

The prevalence and histopathological features of white striations parallel to muscle fibers (white lines) in the deep pectoral muscles (DPM) of broiler chickens (brand chickens) were investigated. The body weight of chickens with white lines was significantly heavier than that of chickens without white lines. However, some chickens with below-average weight exhibited moderate to severe degree of white lines. The prevalence was higher in male chickens than in female chickens. There was a weak correlation between the degree of white lines in DPM and in superficial pectoral muscles (SPM). However, some chickens with moderate to severe white lines in DPM showed only subtle to mild white lines in SPM. From histopathological examination, the white lines were found to be adipose tissue that proliferated between muscle fiber bundles. When compared with grossly normal DPM, the adipose tissue appeared more frequently in DPM with white lines, but the degree of degeneration of muscle fibers was not markedly different. From these findings, these white lines were thought to be intramuscular fat deposition without the degeneration of muscle fibers.