Vitamin E and Selenium Levels are Within Normal Range in Pigs Diagnosed with Mulberry Heart Disease and Evidence for Viral Involvement in the Syndrome is Lacking

Shen, H.; Thomas, P. R.; Ensley, S. M.; Kim, W.‐I.; Loynachan, A. T.; Halbur, P. G.; Opriessnig, T.

Mulberry heart disease (MHD) in pigs is characterized by lesions of acute haemorrhagic myocarditis and myocardial necrosis. The objectives of this study were to determine the levels of vitamin E and selenium and 13 other trace minerals in heart and liver tissues and to determine the prevalence of certain viral infections in heart tissues from MHD‐affected and MHD‐unaffected pigs and the vitamin E and selenium concentration in feed samples from selected farms with MHD. Based on the pathological examination, 114 pigs were separated into MHD lesion‐negative (L‐NEG) (n = 57) and MHD lesion‐positive (L‐POS) (n = 57) groups. Seventy‐three samples (40 L‐NEG and 33 L‐POS) were subjected to chemical analysis, and 66 (32 L‐NEG and 34 L‐POS) were subjected to PCR detection for viral pathogens. Lower (P < 0.05) levels of myocardial copper, lower (P < 0.05) levels of hepatic magnesium and higher (P < 0.05) levels of myocardial and hepatic sodium were detected in the L‐POS cases. Although lower (P < 0.05) levels of hepatic selenium were detected in L‐POS group, all were within the normal range. Analysis of feed samples (n = 22) revealed that selenium levels in all the samples were above the legal limit (0.3 ppm) for pigs. Vitamin E levels in all feed samples were above 20 IU/kg. Among the 66 pigs subjected to PCR detection, there were 19, 4, 13, 8, 2 and 1 animals positive for porcine circovirus type 2, porcine reproductive and respiratory syndrome virus, pan‐herpes virus, porcine enterovirus, pan‐pestivirus and porcine parvovirus, respectively. Clear evidence of viral association with L‐POS was lacking.