The effect of essential oils on performance, immunity and gut microbial population in weaner pigs

In the present study, a total of 240 piglets weaned at 28 days were randomly allocated to four treatments at 36 days of age: a control (no antibiotic growth promoters), and control supplemented with increasing levels of an encapsulated essential oils (EO) product (50, 100 or 150 g/tonne of feed). The average bodyweight at 36 days of age was 10.9 ± 0.14 kg. The main active components present in the EO product were thymol and cinnamaldehyde. Each treatment was composed of 6 replicates, with 10 pigs per replicate. Feed intake, body weight gain and feed conversion ratio were measured over a 35-day period. On day 35, blood samples were taken from 2 pigs per replicate in order to determine the levels of immunoglobulins (IgG, IgA and IgM) and complement components (C3 and C4). In addition, fecal samples from 3 piglets per replicate were taken for the determination of Lactobacillus and E. coli counts. The results showed that adding EO to the control diet reduced the occurrence of diarrhea and decreased E. coli counts in feces (P < 0.05). Feeding EO also increased lymphocyte transformation and leucocyte phagocytosis rates, as well as the levels of IgA, IgM, C3 and C4 in blood (P < 0.05). The addition of EO at 100 and 150 g/tonne improved daily weight gain and feed conversion ratio (FCR) of weaner pigs (P < 0.05). The results demonstrated that the encapsulated EO can improve performance, immunity and gut microflora of newly weaned pigs.