Peroxidised dietary lipids impair intestinal function and morphology of the small intestine villi of nursery pigs in a dose-dependent manner

The objective of this study was to investigate the effect of increasing degrees of lipid peroxidation on structure and function of the small intestine of nursery pigs. A total of 216 pigs (mean body weight was 6.5 kg) were randomly allotted within weight blocks and sex and fed one of five experimental diets for 35 d (eleven pens per treatment with three to four pigs per pen). Treatments included a control diet without added lipid, and diets supplemented with 6 % soyabean oil that was exposed to heat (80 degrees C) and constant oxygen flow (1 litre/min) for 0, 6, 9 and 12 d. Increasing lipid peroxidation linearly reduced feed intake (P<0.001) and weight gain (P=0.024). Apparent faecal digestibility of gross energy (P=0.001) and fat (P<0.001) decreased linearly as the degree of peroxidation increased. Absorption of mannitol (linear, P=0.097) and d-xylose (linear, P=0.089), measured in serum 2 h post gavage with a solution containing 0.2 g/ml of d-xylose and 0.3 g/ml of mannitol, tended to decrease progressively as the peroxidation level increased. Increasing peroxidation also resulted in increased villi height (linear, P<0.001) and crypt depth (quadratic, P=0.005) in the jejunum. Increasing peroxidation increased malondialdehyde concentrations (quadratic, P=0.035) and reduced the total antioxidant capacity (linear, P=0.044) in the jejunal mucosa. In conclusion, lipid peroxidation progressively diminished animal performance and modified the function and morphology of the small intestine of nursery pigs. Detrimental effects were related with the disruption of redox environment of the intestinal mucosa.