Effect of Immune Stress on Growth Performance and Immune Functions of Livestock: Mechanisms and Prevention

Dietary Litsea cubeba essential oil supplementation improves growth performance and intestinal health of weaned piglets

This paper was to determine the effects of dietary Litsea cubeba essential oil (LEO) supplementation on growth performance, immune function, antioxidant level, intestinal morphology and microbial composition in weaned piglets. One hundred and ninety-two piglets (Duroc × [Large White × Landrace]) with 6.85 ± 0.22 kg mean body weight weaned at 21 d of age were randomly assigned to 4 treatment groups with 8 replicates and were fed with a basal diet (CON) or CON diet containing 100 (LLEO), 200 (MLEO) and 400 (HLEO) mg/kg LEO. The results revealed that HLEO supplementation (P < 0.05) increased the average daily gain on d 28 compared with CON. MLEO and HLEO supplementation decreased (P < 0.05) feed conversion ratio. LEO-containing diets had a lower (P < 0.05) diarrhea rate. Supplementation with HLEO increased (P < 0.05) total antioxidant capacity (T-AOC) both in the serum and liver. Meanwhile, the supplementation of MLEO and HLEO resulted in higher (P < 0.05) glutathione peroxidase (GPx) activities both in serum and liver. Supplementation of HLEO increased (P < 0.05) serum immunoglobulin A, immunoglobulin G and interleukin-10, whereas supplementation with MLEO and HLEO decreased (P < 0.05) tumor necrosis factor-α. Villus height in the duodenum or jejunum was increased (P < 0.05) in the HLEO group, and the villus height to crypt depth ratio in the jejunum was also improved (P < 0.05) in the MLEO group. The addition of LEO increased (P < 0.05) the richness and diversity of the microbial community in the cecum, which mainly increased the relative abundance of Oscillospiraceae _UCG-005, Faecalibacterium, Blautia and Coprococcus. Piglets supplemented with HLEO increased (P < 0.05) the concentration of short chain fatty acids (SCFA), including acetic acid in the cecum and propionic acid in the colon. In conclusion, these findings indicated that LEO supplementation improved growth performance and intestinal health in weaned piglets.