Effects of combined application of benzoic acid and 1-monolaurin on growth performance, nutrient digestibility, gut microbiome and inflammatory factor levels in weaned piglets

BACKGROUND: Our previous study observed that benzoic acid and 1-monolaurin have a synergistic bactericidal effect. Moreover, their improvement effect of benzoic acid and 1-monolaurin on the growth performance and diarrhea of weaned piglets was better than the two feedings alone. However, it is not clear how the combination of benzoic acid and 1-monolaurin affects the growth performance of weaned piglets. Therefore, 100 weaned piglets (mean weight 7.03 ± 1.04 kg, mean weaning age 26 d) were randomly divided into two groups: (1) basal diet control (CON); (2) basal diet supplemented with 0.6% benzoic acid and 0.1% 1-monolaurin (CA). The experiment lasted 28 days after weaning. The effects of benzoic acid and 1-monolaurin supplementation on growth performance, apparent nutrient digestibility, intestinal flora composition and function, and inflammatory factor levels of weaned piglets were investigated. RESULTS: The feed conversion efficiency of piglets in the CA group between 15 and 28 d and 1 and 28 d after weaning was significantly higher than that in the CON group (P < 0.05). Additionally, the diarrhea proportion and frequency of piglets in the CA group 1–14 days post-weaning were significantly decreased (P < 0.05). The apparent digestibility of dry matter, organic matter and crude protein of piglets in the CA group was significantly higher than the CON group on days 14 and 28 (P < 0.05). The microbial composition in the cecal digesta of piglets was detected. The results indicated that the CA group piglets were significantly supplemented with g_YRC22 at day 14 and g_Treponema, g_Pseudomonas, and g_Lachnobacterium at day 28 (P < 0.05; log LDA > 2). No significant difference was observed between the CON and CA groups in the content of short-chain fatty acids. In addition, serum IL−1β level significantly decreased at day 28 in the CA group compared with the CON group, while serum endotoxin content was significantly reduced at day 14. CONCLUSION: Therefore, dietary supplementation of 0.6% benzoic acid and 0.1% 1-monolaurin enhanced growth performance and nutrient digestibility, affected gut microflora composition, and decreased systemic inflammatory response and intestinal permeability of weaned piglets. These outcomes provide a theoretical basis for applying of benzoic acid and 1-monolaurin over weaned piglets.