Effects of dietary conjugated linoleic acid on the duodenal mucosal immunity response and redox status of broiler chicks infected with Eimeria acervulina

The present experiment investigated the effects of conjugated linoleic acid (CLA) on the growth performance, oocyst shedding, duodenal mucosal immune response, and redox status of broiler chicks infected with Eimeria acervulina. Totally 144 birds were fed either the basal diet or 1.5% CLA diet for 21 days, and then half of them from each dietary treatment were inoculated with 10 000 Eimeria acervulina sporulated oocysts. Compared with the basal diet, the 1.5% CLA diet partially ameliorated the growth inhibition (P < 0.01) and decreased the oocyst shedding of broiler chicks at ca. 6-9 days post-inoculation (P < 0.01). Additionally the dietary CLA significantly increased the percentage of CD8(+) T lymphocytes in the duodenal epithelium (P < 0.05), and showed no obvious effect on the interferon. expression in duodenal mucosa (P > 0.05). The dietary CLA also notably suppressed the increase of malondialdehyde (P < 0.05) and the decrease of glutathione concentration (P < 0.01) in duodenal mucosa of the infected birds, without changing the activities of total superoxide dismutase and catalase (P > 0.05). These results demonstrate the protective effect of dietary CLA on the broiler chicks infected with Eimeria acervulina, and anticoccidial effects of dietary CLA are most likely related to the increased proportions of CD8(+) T lymphocytes in duodenal epithelium and the inhibition on the decrease of duodenal mucosal glutathione after Eimeria acervulina infection.