Journal of Animal Science and Veterinary Medicine

Crude oil contamination of feed resources can induce organomegaly, organ atrophy, and histopathological lesions in livestock due to the bioaccumulation of polycyclic aromatic hydrocarbons in metabolically active organs. This study evaluated the ameliorative effects of vitamin E alone and in combination with selenium on relative organ weights and histopathology of growing pigs previously exposed to graded levels of crude oil–contaminated diets. Thirty-six crossbred pigs (Large White × Landrace; 18 males and 18 females; 15.8 ± 1.4 kg; 10–12 weeks old) were initially exposed to 0, 5, 10, or 15 g Bonny Light crude oil/kg feed for four weeks, followed by a four-week amelioration phase in a 4 × 3 factorial completely randomized design comprising basal diet (no treatment), vitamin E (200 mg/kg), and vitamin E plus selenium (200 mg vitamin E + 5 mg selenium/kg). Relative organ weights (liver, kidney, heart, and spleen) were measured after slaughter, and histopathological evaluation of selected organs was conducted using standard haematoxylin and eosin staining. Data were analysed using factorial ANOVA with Tukey’s HSD at p < 0.05. Pigs exposed to 15 g/kg crude oil without treatment showed significantly increased relative liver (3.2 g/100 g) and spleen (2.0 g/100 g) weights compared to control values (2.6 and 1.4 g/100 g, respectively), indicating hepatomegaly and splenomegaly associated with fatty degeneration and inflammatory infiltration. Histological findings revealed cytoplasmic vacuolation, vascular dilation, and periportal inflammation in the liver, while heart and spleen tissues remained largely normal. Vitamin E alone partially restored organ weights and reduced tissue damage, particularly at lower contamination levels, whereas combined vitamin E and selenium achieved near-complete restoration of organ weights and markedly improved histological architecture even at higher contamination levels. These results suggest that vitamin E is effective up to moderate contamination levels, while its combination with selenium provides superior ameliorative effects against crude oil–induced toxicity in growing pigs.

Abbreviations: PCV, packed cell volume; Hb, haemoglobin; RBC, red blood cell; WBC, white blood cell; EDTA, ethylenediaminetetraacetic acid; NRC, National Research Council; ROW, relative organ weight; H&E, haematoxylin and eosin; SEM, standard error of mean; GSH-Px, glutathione peroxidase; MDA, malondialdehyde, ROS, reactive oxygen species; PAHs, polycyclic aromatic hydrocarbons.