Effects of supplementary thyme on immunity responses, antioxidant indices, rumen enzymes concentrations and rumen bacteria composition in Hu sheep

The thyme (Thymus vulgaris L.) plant contains volatile oils, flavonoids and monoterpenoids, which are reputed to possess medicinal properties. The present study examined the effects of supplementary thyme intake on immunity responses, antioxidant indices, rumen enzymes concentrations and rumen bacteria composition in sheep. Six rumen-fistulated, 12-month-old Hu rams (63.1 ± 8.54 kg) were used in a replicated 3 × 3 Latin square design in which three levels of air-dried thyme were offered: 0 g/d (CON), 16 g/d (T16) and 80 g/d (T80). The serum concentrations of albumin (p = 0.06), total proteins (p = 0.06) and β-hydroxybutyric acid (p = 0.07) tended to increase linearly with an increase in thyme intake. Concentration of serum non-esterified fatty acids increased (p = 0.03) and changed quadratically (p = 0.02) with an increase in thyme intake. Serum antioxidant indices were not affected by thyme intake. The concentration of rumen lipase increased linearly (p < 0.01) with an increase in thyme intake, and was greater in the T80 than the CON rams. Thyme intake increased (p < 0.05) the abundance of the rumen probiotics f__Lactobacillaceae, g__Lactobacillus and o__Lactobacillales, and the abundance of g__UCG-002 and g__Eubacterium_saphenum_group. It was concluded that thyme can: 1) promote protein synthesis and utilization; 2) enhance immunity responses; 3) mediate energy metabolism; and 4) increase the abundance of rumen probiotics in sheep. In the current study, the best response was observed at an intake of 80 g of air-dried thyme/d.