Effects of dose and formulation of carvacrol and thymol on bacteria and some functional traits of the gut in piglets after weaning

Abstract

Two trials were conducted to study the effects of dose and formulation of carvacrol and thymol on bacterial counts, metabolites and functional traits of the gut in weaned piglets. In the first experiment (Exp. I), 25 piglets (28 d, 6.59 +/- 0.48 kg BW) were allocated to five dietary treatments: a control diet, or the same diet supplemented with either carvacrol or thymol at doses of 500 and 2000 mg kg(-1). In the second experiment (Exp. II), 35 piglets (28 d, 7.99 +/- 0.73 kg BW) were assigned to seven dietary treatments: the same control diet as in Exp. I, or this diet supplemented with thymol in one of three formulations (on celite, on alphacel or microencapsulated) at doses of 500 and 2000 mg kg(-1). At 11/12 days post-weaning piglets were euthanised, and digesta from stomach, proximal and distal small intestine were sampled for bacteriological and biochemical analysis. Small intestinal tissue was sampled for histomorphological determinations. In none of the experiments or sections of the gut was the number of bacteria lowered by the carvacrol or thymol supplementation. In Exp. I, the villus/crypt ratio at the distal small intestine for the experimental diets (1.30-1.32) was higher than for the control diet (1.24) (p < 0.05). Thymol fed animals in Exp. II had a lower number of intra-epithelial lymphocytes at the proximal (p < 0.05) and at the distal (p < 0.1) small intestine as compared to control animals. Mean concentration of the active ingredient in the stomach and proximal small intestine for the 2000 mg kg(-1) carvacrol diet was 521 and 5 mg kg(-1) fresh digesta, respectively, and for the 2000 mg kg(-1) thymol diets it ranged between 475 and 647 and between 13 and 24 mg kg(-1) fresh digesta, respectively. Cumulative absorption in the proximal small intestine was higher than 90% for all treatments and was not affected by formulation type. These data suggest that carvacrol and thymol can improve gut health, but evidence for clear antimicrobial effects towards the major culturable bacteria of the pig foregut is limited.

Effect of dose of thymol and supplemental flavours or camphor on palatability in a choice feedings study with piglets

“…In the current study feed choice is certainly driven by the feed flavour (short duration and daily alternating feeder position) in contrast to the 12-day duration of the other study where nutritional, metabolic and physiological factors may become relevant. However, in Michiels et al (2010) no such arguments were found that could explain the higher feed intake in the no choice-feeding situation. Perhaps, thymol's pungency stimulated digestive secretions and intestinal motility leading to shortening of digesta transit and increased feed consumption as was evidenced with several spices (Platel and Srinivasan, 2001).…”

“…The preference for feed containing 1250 mg/kg was 36.8% and thus intermediate with the results of trial A. In previous work (Michiels et al, 2010) the addition of 500 and 2000 mg/kg thymol to diets for freshly weaned piglets in a 12-day trial was investigated. Although the objective in that study was not to evaluate the effect on animal performances, the actual feed intake relative to the control diet was 123 and 99% for the treatments 500 and 2000 mg/kg thymol respectively.…”

“…Inconsistencies between choicefeeding and no choice-feeding trials have been found frequently (Torrallardona and Solà-Oriol, 2009). Differences in basal diet composition between the two studies (current choice-feeding study vs. Michiels et al, 2010; no choice-feeding) could be involved. In the current study feed choice is certainly driven by the feed flavour (short duration and daily alternating feeder position) in contrast to the 12-day duration of the other study where nutritional, metabolic and physiological factors may become relevant.…”

“…The latter is especially relevant because when antimicrobial effects are pursued high inclusion levels might be needed (Michiels et al, 2010). Windisch et al (2008) stated that choice-feeding studies are to be compiled to test palatability.…”

Evaluation of oregano essential oil as a growth promoter and resistance stimulator against Ichthyophthirius multifiliis (Protozoa, Ciliophora) in silver catfish juveniles, Rhamdia sp. (Siluriformes, Heptapteridae)

“…In this context, as an alternative to the use of synthetic chemotherapeutics, several natural products based on aromatic plants have drawn great attention and have been studied in different species of zootechnical interest, such as fish (ABBAS et al, 2012;CHAVES et al, 2011;GIANNENAS et al, 2003;MICHIELS et al, 2010;ZHENG et al, 2009). The search for alternative additives with the potential to enhance zootechnical performance and improve the immune system of the animal without leaving any residue in the fish meat or resulting in resistant bacteria has driven research on the inclusion of natural products in fish diets (CAMPAGNOLO et al, 2013).…”