Effects of microencapsulated organic acids and essential oils supplementation on performance and rectal temperature in challenged weaning pigs

Lipopolysaccharide (LPS) is a complex of lipids and sugars and is an essential component of the cell walls of gram negative bacteria (e.g. Escherichia coli and Salmonella spp.). Injection of LPS induces pathologic phenomena, which can lead to immune and inflammatory responses (Wu et al. 2015). Addition of organic acids in feed can improve the growth of piglets (Costa et al. 2013), and essential oils are considered anti-inflammatory (Yoon et al. 2010). The objective of the study is to determine the effect of microencapsulated blends of organic acids and essential oils (MOE) supplementation on rectal temperature and growth in weaning pigs subjected to a LPS challenge.

A total of 20 weaning (21 days) pigs ((Landrace × Yorkshire) × Duroc) with an initial bodyweight of 4.43 ± 0.6 kg (mean ± s.d.) were randomly allocated to four treatments with five replicates per treatment per pen for a 28 days experimental period. The average temperature of the pig accommodation area was 30 ± 1°C. Treatments were: (1) basal diets + 0.2% MOE+ LPS injection; (2) basal diets + 0.2% MOE + saline injection; (3) basal diets + LPS injection; and (4) basal diets + saline injection. The basal diet contained 14.9 MJ/kg digestible energy and 1.65% lysine. On d 28, LPS (SIGMA, from Escherichia coli O111:B4, L2630) was injected at 100 μg/kg × bodyweight. Injections were injected intramuscularly into the thigh, and rectal temperature of the pigs was recorded after injection of LPS or saline 0, 4, 8, 12 and 16 h. All data were analysed by ANOVA using the General Linear Models (GLM) procedure of SAS (v9.2, SAS Institute Inc., Cary, NC, USA). Results are presented in Table 1.

Table 1.  Effects of microencapsulated blends of organic acids and essential oils on growth performance and rectal temperature in weaning pigs challenged by LPS

Supplement with 2% MOE significantly improved the final bodyweight, average daily gain (ADG) and average daily feed intake (ADFI) (P < 0.05). However, feed efficiency (G:F) was not significantly different (P > 0.05). At 4, 8, 12, and 16 h after challenge, LPS (+MOE+LPS, −MOE+LPS) gave significantly higher rectal temperature than the saline treatment (P < 0.01). In conclusion, LPS injection can increase rectal temperature and MOE supplementation increased growth performance in weaning pigs, however, MOE could not inhibit the LSP-induced hyperthermia.