Effect of dietary phytobiotic mixture on growth performance, nutrient utilization, and immunity in weaned piglets

This study investigated the effects of dietary phytobiotic mixture on growth performance, blood profiles, immune response, and fecal microorganisms in weaned piglets. Twenty four weaned crossbred piglets were equally divided into four groups in a completely randomized design. The animals in 4 groups were fed a basal diet added with (1) no antibiotics and phytobiotics (CON), (2) bacitracin (0.5 g/kg; AB), (3) a blend of C innamomum zeylanicum and Trachyspermum copticum essential oils (0.3 g/kg and 0.4 g/kg, respectively; EO), and (4) plant extracts (PEO) of Mikania micrantha and Garcinia lanceifolia (2.8 g/kg and 1.4 g/kg, respectively) and C. zeylanicum and T. copticum essential oils (0.3 g/kg and 0.4 g/kg, respectively). Inclusion of AB, EO, and PEO did not affect final body weight, average daily gain, feed intake, feed efficiency, and nutrient digestibility. Compared with the CON, serum protein profiles were not affected, but a few lipid profiles were improved, particularly cholesterol, low-density lipoprotein, and high-density lipoprotein in the EO and PEO groups. Lymphocyte proliferation index and concentrations of IgG and IgA and TNF-α were not affected by any treatments. The concentrations of IgM increased ( P = 0.04) at 28 days and tended to increase ( P = 0.10) at 56 days in the EO group. Serum IL-1β levels decreased on days 28 and 56 in the EO and PEO groups. Fecal Lactobacilli population generally increased ( P < 0.01) in the AB, EO, and PEO groups compared with the CON. Fecal enterobacterial numbers were always greater for AB than for CON, EO, or PEO, but enterobacterial populations were sometimes lower in the EO group than the CON group. In conclusion, dietary EO or PEO has no effect on the growth performance, but it may improve a few lipid profiles, immune responses, and fecal microbial populations in piglets.