Effects of zinc oxide and monoglyceride blend on intestinal immune, health and microbiota responses of weanling pigs.

Organic acids are increasingly being investigated as alternatives to zinc oxide (ZnO) in nursery pig diets. Monoglycerides can act in distal parts of the intestine, promoting intestinal health, also reducing bacterial fermentation in hindgut. This study aimed to determine the effects of dietary supplementation based on a blend of monoglycerides (C4:C8:C10) (MBLEND) in replacement to ZnO during the nursery phase on growth-performance and intestinal health. Ninety-six piglets were used (average weight 7.08 ± 0.837 kg) with 25 days of age during 42 days, divided into three treatments and eight replicates in a randomized block design. The treatments were: CON - Negative control (basal diet without additive supplementation); MBLEND - Fatty acids (basal diet with monoglycerides blend (C4:C8:C10) additive supplementation at 1.5 kg/ton in the pre-initial 1 and pre-initial 2 phases, 1.0 kg/ton in the initial 1 and initial 2 phases) and ZnO - Zinc oxide (basal diet with zinc oxide supplementation at 3000 ppm in the pre-initial 1, pre-initial 2 and initial 1 phases, 2000 ppm in the initial 2 phase). Both ZnO and MBLEND groups did not influence (P>0.05) growth performance during all phases. The inclusion of the MBLEND improved (P<0.05) dry matter (DM), crude protein (CP), and ashes digestibility when compared to CON and ZnO groups. The use of ZnO reduced (P<0.05) IL-1 β cytokine expression in the piglets' jejunal mucosa. ZnO increased evenness and affected beta-diversity (P<0.05) compared to CON and MBLEND. The ZnO group increased Tannerellaceae, Bacteroidaceae, and Muribaculaceae families and reduced Escherichia Coli-Shigella and Desulfovibrio generas (q<0.05). Although there were similar results on growth performance, ZnO modulated cecal microbiota and reduced inflammatory ileal cytokines and MBLEND improved protein and ashes digestibility.