Outbreaks of nutritional cardiomyopathy in pigs in Brazil

Abstract

Dilated cardiomyopathy (DCM) is a condition that affects the myocardium, seldom reported in pigs. The DCM is characterized by ventricular dilation, which results in systolic and secondary diastolic dysfunction and can lead to arrhythmia and fatal congestive heart failure. This study described the clinical, pathological, chemical and toxicological findings of nutritional dilated cardiomyopathy (DCM) in nursery pigs through natural and experimental studies. Naturally occurring cases of DCM in three swine farms were investigated through necropsy (fourteen pigs), microscopic, virological, chemical and toxicological exams for the detection of the etiology. The experimental study was conducted with nine 40 days-old piglets, which were divided into three groups of three piglets each. Group 1 was fed with the suspected diet of the naturally occurring cases, Group 2 with half of the suspected diet and half of a control diet, and Group 3 received only the control diet. Clinical signs were recorded. All pigs were submitted of euthanized, necropsie and collection sample for laboratories exams, after 15 days of experiment onset. At the necropsy, all naturally occurring cases had bilateral cardiac dilatation associated to hepatic enhanced lobular pattern (nutmeg liver) and lungs edema. Microscopically, the heart revealed severe hypertrophy and vacuolization of cardiomyocytes, as well as myofiber disarray. Feed analysis revealed low-quality standard soybean meal. After the suspected feed was replaced, clinically ill pigs recovered, and mortality ceased. At the experimental study, two piglets from Group 1 had cough, dyspnea and diarrhea. At the necropsy, these animals had similar gross and microscopic lesions to the natural cases. The nutritional DCM in pigs may be associated to the diet with low-quality soybean meal, as it was further confirmed through an experimental study.

Causes of death in growing-finishing pigs in two technified farms in southern Brazil

“…In pigs there are reports of this disease associated with gossypol and fumonisin poisoning, besides cardiomyopathies of undefined cause (Loynachan 2012, Sobestiansky 2012, Collins et al 2015, as found in this study. Recently, this disease has been described in Brazil and experimentally reproduced in nursery pigs; in the referred study a nutritional etiology was suggested (Cruz et al 2019). In the present study, although macroscopic and histopathological lesions were similar to those observed by Cruz et al (2019), the disease affected pigs sporadically during the growth and finishing phases, in two farms with distinct genetics and nutritional practices, and not as outbreaks, what does not allow us to associate these cases with any epidemiological factor.…”

“…Pigs with dilated cardiomyopathy presented cardiomegaly ( Fig.6A), with marked dilation of the cardiac chambers ( Fig.6B), especially the ventricles (Cruz et al 2019). These pigs also had extracardiac lesions of congestive heart failure, such as ascites ( Fig.6C), pulmonary edema and "nutmeg liver" (Fig.6D).…”