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During meat inspections in pigs, dystrophinopathies are among the muscle lesions targeted for disposal. In this study, the authors examined the lesions and the distribution of dystrophin expression in 25 pigs with dystrophinopathy. In addition, complementary deoxyribonucleic acid (cDNA) sequencing and western blotting were performed in 6 of the 25 cases, all of which were characterized by degeneration, necrosis, and fat replacement of muscle fibers. Comparing the results of immunohistochemistry with anti-dystrophin antibodies that recognized at different sites in the protein, the authors noted that the loss of dystrophin expression was most pronounced in the C-terminus-recognizing antibody (19/25 cases). The authors detected 5 missense mutations and 3 types of shortened transcripts generated by the skipping of exons in the cDNA, which were associated with the pathogenesis. One missense mutation had been reported previously, whereas the remaining mutations identified had not been previously documented in pigs. In the cases with shortened transcripts, normal-sized transcripts were detected together with the defective transcripts, suggesting that these mutations were caused by splicing abnormalities. In addition, they were in-frame mutations, all of which have similar pathogeneses of Becker muscular dystrophy in humans. These cases were 6 months of age and exhibited macroscopic discoloration, fatty replacement, and muscle degeneration, suggesting that the effect of these mutations on skeletal muscle was significant., Competing Interests: Declaration of Conflicting InterestsThe author(s) declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Necropsy of a 52-day-old Camborough pig revealed numerous cardiac malformations. The positional relationship of the atria, ventricles and great vessels was a mirror image type (I, L and L): inverted arrangement of the atria, with a left-sided right atrium and right-sided left atrium (situs inversus); inverted arrangement of the ventricles, with a left-sided morphological right ventricle and right-sided morphological left ventricle (L-loop); and aortic valve to the front left relative to the pulmonary valve (L-malposed). The major malformations included an ostium secundum atrial septal defect, cor triatriatum sinister (CTS), a subpulmonary ventricular septal defect and a bicuspid pulmonary valve. Histological examination revealed myocyte hypertrophy, focal myocardial necrosis and calcification in the left morphological right ventricle of the heart. To the best of our knowledge, this is the first report of CTS in pigs. Although the individual malformations found in the present case are not unique, an unusual combination of these cardiac malformations has not been described in animals., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Atypical porcine pestivirus (APPV), which has been confirmed to be associated with congenital tremor (CT) in pigs, is a newly discovered porcine virus that has been found in the Americas, Europe and Asia; however, no report of APPV in Japan has been published. We identified an APPV in the central nervous system of Japanese piglets with CT and firstly determined and analysed the complete genome sequence. Phylogenetic analysis using the complete genome nucleotide sequence of the Japanese APPV, named Anna/2020, and those of APPVs from the NCBI database showed that APPVs were divided into three genotypes (genotypes 1 to 3), and that Anna/2020 clustered with the genotype 3 APPV strains, but distantly branched from these strains. Pairwise complete coding region nucleotide sequence comparisons revealed that there was 94.0%- 99.7% sequence identity among the genotype 3 strains, while Anna/2020 showed 87.0%-89.3% identity to those genotype 3 strains, suggesting that Anna/2020 represents a novel APPV lineage within genotype 3. Retrospective examinations using RT-PCR revealed one genotype 1 and two novel genotype 3 APPVs from pigs without CT, and that novel genotype 3 APPVs have been prevalent in Japan since at least 2007., (© 2021 Wiley-VCH GmbH.)

We describe a case of human Becker muscular dystrophy (BMD)-like myopathy that was characterized by the declined stainability of dystrophin at sarcolemma in a pig and the immunostaining for dystrophin on the formalin-fixed, paraffin-embedded (FFPE) tissue. The present case was found in a meat inspection center. The pig looked appeared healthy at the ante-mortem inspection. Muscular abnormalities were detected after carcass dressing as pale, discolored skeletal muscles with prominent fat infiltrations and considered so-called "fatty muscular dystrophy". Microscopic examination revealed following characteristics: diffused fat infiltration into the skeletal muscle and degeneration and regeneration of the remaining skeletal muscle fibers. Any lesions that were suspected of neurogenic atrophy, traumatic muscular degeneration, glycogen storage disease or other porcine muscular disorders were not observed. The immunostaining for dystrophin was conducted and confirmed to be applicable on FFPE porcine muscular tissues and revealed diminished stainability of dystrophin at the sarcolemma in the present case. Based on the histological observations and immunostaining results, the present case was diagnosed with BMD-like myopathy associated with dystrophin abnormality in a pig. Although the genetic properties were not clear, the present BMD-like myopathy implied the occurrence of dystrophinopathy in pigs. To the best of our knowledge, this is the first report of a natural case of myopathy associated with dystrophin abnormalities in a pig.