Effect of Thymol Addition and Withdrawal on Some Blood Parameters, Antioxidative Defence System and Fatty Acid Profile in Rabbit Muscle

Abstract

Thymol concentrations in rabbit plasma, intestinal wall (IW) and faeces were detected, and the effects of thymol application and withdrawal on biochemical, antioxidant parameters and fatty acids (FA) in blood (B) and muscle (M) were studied. Forty-eight rabbits were divided into two experimental groups (control, C and with thymol 250-mg/kg feed, T). Thymol was administered for 21 days (TA) and withdrawn for seven days (TW). Thymol in plasma correlated with that in the IW (Spearman′s correlation coefficient (rs) = −1.000, p = 0.0167, TA) and was detected in faeces (TA and TW). In TA alkaline phosphatase (p = 0.0183), cholesterol (p = 0.0228), malondialdehyde (p = 0.003), glutathione peroxidase (p = 0.0177) in B and lactate dehydrogenase (M, p = 0.0411) decreased; monounsaturated FA (p = 0.0104) and α-linolenic acid (p = 0.0227) in M increased. In TW urea (p = 0.0079), docosapentaenoic acid (p = 0.0069) in M increased; linoleic acid (p = 0.0070), ∑ n−6 (p = 0.0007) in M and triglycerides decreased (B, p = 0.0317). In TA and TW, the total protein (p = 0.0025 and 0.0079), creatinine (B; p = 0.0357 and 0.0159) and oleic acid (M; p = 0.0104 and 0.0006) increased. Thymol was efficiently absorbed from the intestine and demonstrated its biological activity in blood and the muscles.

Thymol in fattening rabbit diet, its bioavailability and effects on intestinal morphology, microbiota from caecal content and immunity

“…IgA is bound to the receptor at the basolateral surface of enterocytes and subsequently crosses the epithelial layer (Macpherson et al, 2001). Based on our detection of thymol in the intestinal wall and its antioxidant effects as confirmed in previous studies by Placha et al (2019) and Bacova et al (2020), we assume that the higher amount of IgA detected in the intestinal wall is the result of thymol sparing effects on enterocytes and consequently of larger amounts of IgA bonding on their surface. Plasma cells which produce IgA are developed from antigen‐stimulated B cells (Tizard, 2004).…”

“…Bozkurt et al (2012) suggested the protective properties of bioactive compounds on the intestinal villi, particularly carvacrol, thymol and 1,8‐cineol, which they explained in terms of acceleration in the renewal rate of mature enterocytes as a consequence of the sparing effect of these compounds against oxidative damage. Based on previous results from Bacova et al (2020), who confirmed the alleviation of oxidative damage by means of thymol addition to the rabbit diet, and based on thymol detection in the intestinal wall in our study, we assume it has beneficial effect on enterocytes. In their study Rubió et al (2014) attributed important antioxidant activity to the conjugated form of thymol, thymol sulphate.…”

“…Glycosidases, glucuronidases and sulfatases in the intestinal microflora are able to release the parent compounds from their metabolites, which can then be excreted in this form in the faeces. The biotransformation processes are repeated until the thymol is eliminated from the body (Bacova et al, 2020; Placha et al, 2019). As thymol metabolites can be converted back into parental compounds by microbial enzymes in the caecum, we assume that this process together with consumption of cecotrophs containing thymol (metabolised or non‐metabolised) could explain the higher amount of thymol in the caecal content.…”

Effect of Sustained Administration of Thymol on Its Bioaccessibility and Bioavailability in Rabbits

“…Excreted metabolites from enterocytes are converted back to the parent compound and again reabsorbed. Compounds in the liver are metabolized and together with parent compounds are excreted with bile into the duodenum and are then reabsorbed there [ 14 , 17 ]. These repeating processes together with processes of caecotrophy could explain the thymol content in plasma, tissues, and intestinal content after thymol withdrawal, although only in trace amounts.…”

“…Detection of thymol in samples of plasma, tissues and faeces was performed using headspace solid-phase microextraction followed by gas chromatography coupled with the mass spectrometry method as described by Bacova et al [ 14 ] and Placha et al [ 15 ]. Briefly, detection and quantification were carried out using a GC/MS (type HP 6890 GC) system coupled with a 5972-quadrupole mass-selective detector (Agilent Technologies GmbH, Wilmington, DE, USA).…”