Effect of Diet Complexity, Multi-enzyme Complexes, Essential Oils, and Benzoic Acid on Weanling Pigs

Abstract

The objective of this study was to investigate the effect of supplementing a simple corn-soybean meal (SBM) diet with multi-enzyme complexes, essential oils, and benzoic acid on growth performance, serum metabolite profile, serum cytokines, and gut microbiota. Forty-eight gilts and 48 castrated males (initial body weight, 7.96 ± 0.89 kg) weaned at 3 to 4 wk of age were randomly assigned to 4 dietary treatments with 6 replicate pens (4 gilts or 4 castrated males/pen) per treatment. A typical complex diet containing various special ingredients was formulated and used as a positive control (POS) diet. A simple corn-SBM, negative control (NEG) diet was formulated to be iso-lysinic to the POS diet, and the NEG diet was supplemented with multi-enzyme complexes (ENZ) or multi-enzyme complexes, essential oils, and benzoic acid (ALL). Feed additives were included in the diet by replacing the part of corn. All 4 diets were formulated to meet or exceed the 2012 NRC nutrient requirements. During the fourth week of the study, blood samples were collected to determine serum metabolite profile and cytokines. Similarly, fecal samples were collected for bacterial cultivations during the fourth week of the study. Pigs had ad libitum access to feed and water throughout the study. From d 0 to 7, pigs fed the POS diet consumed more (P < 0.05) feed, Lys, and digestible energy (DE) and gained more weight (P < 0.05) than those fed the NEG and ALL diets. Pigs fed the POS diet also consumed more (P < 0.05) DE than those fed the ENZ diet. Similarly, from d 7 to 14, pigs fed the POS diet consumed more (P < 0.05) feed, Lys, and DE and gained more weight (P < 0.05) than those fed the NEG and ALL diets. Pigs fed the POS diet also consumed more (P < 0.05) DE than those fed the ENZ diet. Pigs fed the ENZ diet gained more weight (P < 0.05) than those fed the NEG diet. From d 14 to 21, pigs fed the POS diet consumed more (P < 0.05) feed, Lys, and DE, and gained more weight (P < 0.05) than those fed the other 3 diets. Pigs fed the POS diet consumed more (P < 0.05) DE than those fed the other 3 diets from d 21 to 28. Overall (d 0 to 28), pigs fed the POS diet consumed more (P < 0.05) feed, Lys, and DE, and gained more weight (P < 0.05) than those fed the other 3 diets. Serum total protein concentration in pigs fed the ENZ and ALL diets was greater (P < 0.05) than those fed the POS and NEG diets. Serum albumin concentration in pigs fed the POS diet was greater (P < 0.05) than those fed the NEG and ALL diets, and it was greater (P < 0.05) in pigs fed the ENZ diet than those fed the NEG diet. Serum globulin and SUN concentrations in pigs fed the POS diet were less (P < 0.05) than those fed the other 3 diets. The albumin to globulin ratio, and glucose and cholesterol concentrations in pigs fed the POS diet were greater (P < 0.05) than those fed the NEG, ENZ, and ALL diets. Dietary treatments had no effect on any of the serum cytokines and fecal microbiota. The results indicated that weanling pigs’ performance can be affected by dietary treatments. Pigs fed the complex diet performed better and had different serum metabolite profile compared with those fed the simple corn-SBM diets. Supplementation of the simply corn-SBM diet with multi-enzyme complexes, essential oils, and benzoic acid had no effect on growth performance. Similarly, serum metabolism profile, cytokine concentrations, and fecal microbiota concentrations in weanling pigs were generally not affected by supplementation of the NEG diet with various feed additives. Further research is needed to explore the possibility of using a simple corn-SBM diet for weanling pigs by supplementing with various feed additives.