Single components of botanicals and nature-identical compounds as a non-antibiotic strategy to ameliorate health status and improve performance in poultry and pigs

Abstract

In the current post-antibiotic era, botanicals represent one of the most employed nutritional strategies to sustain antibiotic-free and no-antibiotic-ever production. Botanicals can be classified either as plant extracts, meaning the direct products derived by extraction from the raw plant materials (essential oils (EO) and oleoresins (OR)), or as nature-identical compounds (NIC), such as the chemically synthesised counterparts of the pure bioactive compounds of EO/OR. In the literature, differences between the use of EO/OR or NIC are often unclear, so it is difficult to attribute certain effects to specific bioactive compounds. The aim of the present review was to provide an overview of the effects exerted by botanicals on the health status and growth performance of poultry and pigs, focusing attention on those studies where only NIC were employed or those where the composition of the EO/OR was defined. In particular, phenolic compounds (apigenin, quercetin, curcumin and resveratrol), organosulfur compounds (allicin), terpenes (eugenol, thymol, carvacrol, capsaicin and artemisinin) and aldehydes (cinnamaldehyde and vanillin) were considered. These molecules have different properties such as antimicrobial (including antibacterial, antifungal, antiviral and antiprotozoal), anti-inflammatory, antioxidant, immunomodulatory, as well as the improvement of intestinal morphology and integrity of the intestinal mucosa. The use of NIC allows us to properly combine pure compounds, according to the target to achieve. Thus, they represent a promising non-antibiotic tool to allow better intestinal health and a general health status, thereby leading to improved growth performance.

Thymol and Carvacrol Downregulate the Expression of Salmonella typhimurium Virulence Genes during an In Vitro Infection on Caco-2 Cells

“…In this study, thymol and carvacrol were able to counteract the bacterial challenge by increasing TER values even beyond the non-challenged control and maintaining the high values throughout the experiment. Transepithelial electrical resistance is an indicator of the health status and the tightness of the intestinal epithelium [32], and it is reported that many NIC have anti-inflammatory and antioxidant activity, that in turn can improve gut morphology and integrity as mediated by tight junction proteins [33]. In parallel, thymol and carvacrol also reduced bacterial translocation across the monolayer.…”

Nature-Identical Compounds and Organic Acids Ameliorate and Prevent the Damages Induced by an Inflammatory Challenge in Caco-2 Cell Culture

“…Organic acids and NIC are widely used as feed additives in animal nutrition because of their beneficial effects on growth performance and intestinal morphology, as well as their antibacterial, antioxidant and anti-inflammatory properties [ 10 , 11 ]. This study focused on the activity of selected OA, citric and sorbic acid, and NIC, thymol and vanillin on human Caco-2 intestinal cell line.…”

“…In the current study, citric and sorbic acid exerted a slight cytotoxic effect at high doses when used individually, no negative effects were reported when combined with thymol and vanillin. Thymol and vanillin are botanical compounds that have in vitro and in vivo anti-inflammatory and anti-oxidant activity and are widely used in animal nutrition [ 11 , 31 ]. The effects of thymol on intestinal secretory activity were studied ex vivo by Boudry and Perrier [ 32 ] and Michiels et al [ 33 ] demonstrated that thymol induces ion secretions in the small intestine via the nervous system.…”

“…For these reasons, it is important to develop strategies to prevent intestinal barrier failure, supporting animal healthy growth (especially in the early stages of life like weaning). In this context, bioactive compounds such as organic acids (OA) and nature-identical compounds (NIC) can exert a role in the maintenance of intestinal functionality, due to their numerous biological properties [ 10 , 11 , 12 ]. In particular, our research group [ 13 ] reported the beneficial effects of a blend of OA (citric and sorbic acid) and NIC (thymol and vanillin), on porcine intestinal barrier functionality, through a stimulation of the local immune response.…”

Nature-Identical Compounds and Organic Acids Reduce E. coli K88 Growth and Virulence Gene Expression In Vitro

“…Nature-identical compounds are pure chemicals which reflect molecules naturally occurring in essential oils, thus overcoming the intrinsic variability in their composition [14]. Their mode of action is related to their capacity to form pores on the bacterial membrane, induce cell lysis, and inhibit enzyme activity, in addition to anti-inflammatory and antioxidant activities [15][16][17].…”