Changes in the Antioxidant and Mineral Status of Rabbits After Administration of Dietary Zinc and/or Thyme Extract.

This study was aimed at determining the impact of organic zinc (Zn) and thyme extract (TE) administration, given alone or together for 6 weeks, on the antioxidant and mineral status (Zn, Cu, Fe, and Mn) in the plasma and tissues of growing rabbits. A total of 96 rabbits of age 35 days were randomly assigned to one of four treatment groups: a control group (C), a Zn group supplemented with dietary zinc (50 mg/kg), a TE group receiving thyme extract applied in drinking water (1 ml/L), and a Zn + TE group treated with both additives. Lipid peroxidation in the plasma was influenced by Zn intake and in the kidney was affected by both the Zn and TE treatment (P < 0.05). Zn supplementation led to a significant increase in glutathione peroxidase activity (P = 0.017), total antioxidant capacity (P = 0.009) and total thiol groups level (P = 0.047) in the kidney, with the highest values occurring in rabbits receiving the combination Zn + TE. Administration of TE influenced Zn content in the kidney (P < 0.001), while zinc intake decreased Cu concentration in muscle (P = 0.021). In conclusion, the simultaneous administration of organic Zn and TE positively affected the antioxidant response of kidneys and can be used for improving the antioxidant status of growing rabbits.

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

The objective of this study was the detection of thymol in rabbit plasma, tissues, large intestinal content, and faeces. Forty-eight rabbits were divided into control and experimental groups (thymol 250 mg/kg feed). Thymol was administered for 21 days and then withdrawn for 7 days. Concentration of thymol in the intestinal wall (IW) was significantly higher than in plasma (p < 0.05) and liver (p < 0.05); in the kidneys it was significantly higher than in plasma (p < 0.05) and liver (p < 0.05) during thymol addition. Thymol in IW was significantly higher than in plasma also after withdrawal (p < 0.01). Significant correlation (rs = -1.000, p < 0.01) between IW and plasma points to the intensive absorption of thymol from the intestine, while the correlation between plasma and liver (rs = 0.786, p < 0.05) indicates intensive biotransformation and excretion processes in liver. Significant correlation between liver and kidney (rs = 0.738, p < 0.05) confirms the intensive metabolism of thymol in the kidney. During the withdrawal period, thymol was detected above trace amounts only in faeces, and was significantly higher than in the colon during both periods (p < 0.01). Results show intensive biotransformation of thymol in the rabbit organism.