Pathology and oxidative stress changes associated with pregnancy toxaemia in ewes

Abstract

Pregnancy toxaemia is often associated with negative energy balance, and ewes carrying multiple lambs are at risk due to high energy requirements. Deficient nutritional intake with a consequent body fat mobilization for energy, results in production of reactive oxygen species which leads to pathologic changes. This study aimed to evaluate the pathology and oxidative stress changes associated with pregnancy toxaemia in ewes. A total of 33 animals aged 2-3 years with mean weight of 40 ± 0.43 to 60 ± 0.50 kg, were selected from different private breeders’ farms in Ilorin. Twenty-three animals that showed signs of pregnancy toxaemia (recumbence, weakness, and restlessness) were selected and labeled as group A. Ten healthy non-pregnant ewes were also labeled as group B. There was a significant increase in packed cell volume (PCV%), mean corpuscular volume (MCV), and glucose level in ewes with pregnancy toxaemia, while there was a significant decrease in superoxide dismutase (SOD), and catalase (CAT) levels in pregnancy toxaemia group. Postmortem findings included, congested ocular mucous membrane, congested and enlarged lungs, liver and spleen, congested intestinal mucosa and brain meninges, enlarged heart and dilated ventricles, atrophy of fat along the coronary grove of the heart, pale and enlarged liver, excess abdominal fat, and two dead fetuses. On the other hand, the histopathological examination of the pregnancy toxaemia group showed livers with oedematous areas and regular border vacuoles. The lungs were also congested and oedematous There is tubular necrosis and areas of congestion in the kidneys. In conclusion, this study reveals significant hematological and biochemical changes indicative of oxidative stress, alongside pathological findings in various organs such as the liver, lungs, and kidneys. These results underscore the complexity of pregnancy toxaemia and emphasize the need for further research to develop better management strategies.