Effect of The Tea Tree Oil on Meat Quality, Antioxidant Status, and Serum Biochemical Indices in Finishing Pigs

Abstract Background: The increase use of antibiotics continues to posse a threat to public health due to the increasing concern of antibiotic residue. Tea tree oil [TTO] is an extract of the Australian plant Melaleuca alternifolia with anti-inflammatory and anti-oxidant properties. However, there is little information on TTO supplementation on the diet of finishing pigs. Hence, the aim of the present study was to investigate the effect of TTO supplemented diets on serum biochemical indices, fatty acid composition, the mRNA expression of genes, and antioxidant capability in finishing pigs. Results: Our results showed that TTO supplementation increased (P < 0.05) the mRNA expression of insulin-like growth factors -I (IGF-I), growth acceleration hormone [GH] and heart fatty acid binding protein (H-FABP), while the mRNA expression of myostatin gene (MSTN) and calpain-1 (CAST) decreased by TTO supplementation, compared with control group. In addition, TTO supplementation increased (P < 0.05) serum alkaline phosphatase (ALP), immunoglobulin G (IgG), and IgM levels but decreased (P < 0.05) serum aspartate transaminase (AST) concentration, relative to controls. The TTO supplementation increased (P < 0.05) C18:2n6t concentration and decreased (P < 0.05) C12:0 and C16:0 concentration, relative to control group. Dietary supplementation with TTO decreased (P < 0.05) malondialdehyde (MDA) and increased (P < 0.05) glutathione peroxidase (GSH-Px) activity in serum. Compared with control group, TTO supplementation at 200mg/kg increased (P < 0.05) GSH-Px activity in LD muscle.Conclusions: These results indicated that TTO supplementation could improve serum biochemical indices, fatty acid contents, the relative mRNA of expression, and antioxidant capacity of finishing pigs. Therefore, TTO has potential positive effects as a feed additive in pigs industry.