Effects of peroxidized lipids on intestinal morphology, antioxidant capacity and gut microbiome in piglets

This study investigated the effect of peroxidized lipids on piglets' growth performance, intestinal morphology, inflammatory reactions, oxidative stress in the liver, duodenum, jejunum, ileum, and colon, and ileal microbiota. Twenty piglets (Duroc × [Landrace × Yorkshire]; age = 21 d old, BW = 6.5 ± 1 kg) were randomly assigned to two groups with 10 replicates per group and one piglet per replicate. The control group was fed 6% fresh soybean oil and the peroxidized soybean oil (PSO) group fed 6% PSO. The experimental feeding period lasted 24 d. The study found no impact on ADFI, ADG and gain to feed ratio (<i>P</i> > 0.05). However, the PSO group increased the diarrhea index and the serum levels of lactate dehydrogenase triglycerides, cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (<i>P</i> < 0.05), along with decreased concentrations of alanine aminotransferase and blood urea nitrogen (<i>P</i> < 0.05). For oxidative enzymes, PSO increased the concentration of F2-isoprostane in urine (<i>P</i> = 0.032), malondialdehyde (MDA) in the duodenum (<i>P</i> = 0.001) and jejunum (<i>P</i> = 0.004), decreased thiobarbituric acid reactive substances (TBARS) in the liver (<i>P</i> = 0.001) but increased TBARS in duodenum (<i>P</i> = 0.001), and carbonylated proteins in the duodenum (<i>P</i> = 0.003). For antioxidant enzymes, PSO decreased superoxide dismutase (SOD) in the liver (<i>P</i> = 0.001), colon (<i>P</i> = 0.002), and jejunum (<i>P</i> = 0.015), along with glutathione peroxidase (GSH-Px) in the liver (<i>P</i> = 0.008) and NAD(P)H:quinone oxidoreductase 1 (NQO1) in ileum (<i>P</i> = 0.001). For inflammatory reactions, PSO increased interleukin (IL)-1β concentrations in the duodenum and colon, and IL-10 in the jejunum, while decreasing IL-4 concentration in the duodenum (<i>P</i> < 0.05). For intestinal morphology and ileal microbiota, PSO increased ileal crypt depth, while decreasing the crypt-to-villus ratio (<i>P</i> < 0.05). Peroxidized soybean oil increased the relative abundance of <i>Prevotella, Clostridium_sensu_stricto_1, Clostridium_sensu_stricto_6, Pasteurella</i> and <i>Klebsiella</i> (<i>P</i> < 0.05). In conclusion, this study revealed that PSO worsened diarrhea, increasing the ileal crypt depth and the relative abundance of harmful microbiota, and induced oxidative stress and inflammation in the intestines and liver, primarily in the jejunum and ileum.