Effects of essential oils supplementation in different nutrient densities on growth performance, nutrient digestibility, blood characteristics and fecal microbial shedding in weaning pigs

Abstract

This study was conducted to evaluate the effects of essential oils (EO) supplementation in different nutrient density diets on growth performance, nutrient digestibility, blood characteristics (blood urea nitrogen and creatinine), and fecal microflora shedding in weaning pigs. Experiment 1: a total of 140 crossed [(Landrace×Yorkshire)×Duroc] weaning pigs with an initial body weight (BW) of 6.44±0.93kg were used in a 42-day trial. Pigs were randomly allocated into one of four treatment groups in a 2×2 factorial arrangement with two levels of nutrient density (normal and decreased nutrient density) and EO (0 and 0.04%) according to sex and BW (7 replicates each with 2 gilts and 3 barrows). Experiment 2: four weaning barrows [(Landrace×Yorkshire)×Duroc] with an average BW of 15±0.58kg were surgically equipped with T-cannulas at the distal ileum and assigned to 1 of 4 dietary treatments in a 4×4 Latin square design with 4 diets and 4 periods for a 60 days experiment, with two levels of nutrient density (normal and decrease nutrient density) and EO (0 and 0.04%). Pigs fed a normal nutrient density diet had an increased average daily gain (ADG), average daily feed intake (ADFI), and gain:feed (G:F) ratio (P<0.05) than those fed a decreased nutrient density diet. Pigs fed an EO supplementation diet exhibited an increased ADG and G:F ratio (P<0.05) compared with pigs fed a diet without EO supplementation. The apparent total tract digestibility (ATTD) of dry matter (DM) and gross energy (GE) were higher in pigs fed a normal nutrient density diet compared with those fed a decreased nutrient density diet (P<0.05). The coefficient of apparent ileal digestibility (CAID) of DM, nitrogen, GE and amino acids were improved (P<0.05) by EO supplementation and a normal nutrient density diet. The ileal digestibility of most amino acids, except threonine, valine, methionine, proline, glycine, alanine, cystine was increased (P<0.05) in the normal nutrient density diet. In addition, the EO supplementation diet also showed significant positive effects on the CAID of some amino acids (P<0.05), including isoleucine, leucine, lysine, arginine, aspartic acid, serine, and tyrosine. However, no interactive effects were observed in growth performance, nutrient digestibility, blood profiles, and fecal microflora between nutrient density and EO supplementation. In conclusion, dietary supplementation with 0.04% EO has beneficial effects on growth performance and apparent ileal digestibility.