The Effects of Dietary Thyme Oil (Thymus vulgaris) Essential Oils for Common Carp (Cyprinus carpio): Growth Performance, Digestive Enzyme Activity, Antioxidant Defense, Tissue and Mucus Immune Parameters, and Resistance against Aeromonas hydrophila

Abstract

This study evaluated the effects of dietary supplementation of thyme (Thymus vulgaris) essential oil (TVO) on growth performance, digestive enzymes, biochemical parameters, hematological indices, liver enzymes, and pathogen resistance in common carp (Cyprinus carpio). Triplicate groups of fish (15.36 ± 0.10 g) were fed daily with diets supplemented with TVO at 0, 0.5, 1, and 2 percent for 60 days then challenged with Aeromonas hydrophila. The results determined that supplementation of thyme resulted in significantly higher final body weights (FBW) and lower feed conversion ratios (FCR). Furthermore, no mortality was observed in the thyme-supplemented treatments. Regression analysis showed that fish growth parameters were polynomially related to dietary TVO levels. The optimum dietary TVO level, based upon the varied growth parameters, was 1.344 to 1.436%. Digestive enzymes activity, including amylase and protease, significantly increased in fish fed the supplemented diets. The thyme-supplemented diets also significantly increased the biochemical parameters, including total protein, albumin, and acid phosphatase (ACP), compared to the control group. We also observed significant increases in hematological indices, including red blood cells (RBC), white blood cells (WBC), hematocrit (Hct), and hemoglobin (Hb) in common carp fed diets containing thyme oil ( P < 0.05 ). Liver enzymes activity including alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) was also reduced ( P < 0.05 ). Immune parameters, including total protein and total immunoglobulin (total Ig) levels, alternative complement pathway hemolytic (ACH50), lysozyme, protease, and ALP in the skin mucus, and lysozyme, total Ig, and ACH50 in the intestine were higher ( P < 0.05 ) in TVO-supplemented fish. Catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) in the liver were also elevated ( P < 0.05 ) in TVO administered groups. Lastly, thyme-supplementation resulted in higher survival rates after the A. hydrophila challenge compared to the control ( P < 0.05 ). In conclusion, dietary inclusion of thyme oil (1 and 2%) effectively improved fish growth, immune systems, and resistance to A. hydrophila.

Nano-liposome of thyme essential oil promotes growth performance, antioxidant and immune responses to aeromonad septicemia in Nile tilapia, Oreochromis niloticus, fingerlings

“…It is supposed that increase in the activity of these enzymes leads to better digestion. It has been shown that thyme essential oil improves growth performance concurrent with increase in the intestinal activity of digestive enzymes in common carp, Cyprinus carpio (Ghafarifarsani et al, 2022), which supports the present finding. The exact mechanisms of elevation of digestive enzymes are not clear, but it could be a direct effects of TV-NP on enzyme synthesis and release from pancreas, which needs further investigations.…”

“…Wuchang bream, Megalobrama amblycephala, showed similar decrease in lysozyme activity 48 h after an experimental infection with A. hydrophila (Liu et al, 2012). It was shown that thyme essential oil can increase serum and mucosal lysozyme activities in rainbow trout (Zargar et al, 2019) and common carp (Ghafarifarsani et al, 2022), which support the present results. However, the present results show that pre-challenge plasma lysozyme activity is not a suitable predictor of survival after A. hydrophila infection, as shown in 100TV treatment.…”

“…Thyme essential oil mainly contains thymol and carvacrol, two wellknown antioxidants (Giannenas et al, 2012;Hashemipour et al, 2013). Dietary supplementation of 10-20 g/kg of this essential oil has been found to improve antioxidant capacity and reduce lipid peroxidation in rainbow trout, Oncorhynchus mykiss (Sönmez et al, 2015), and common carp (Ghafarifarsani et al, 2022); the later also exhibited improved survival after A. hydrophila infection. This suggests TV-NP may be more efficient than non-protected essential oil in strengthening the antioxidant system.…”

“…It contains a range of bioactive compounds, including thymol, carvacrol, and pcymene, which have antimicrobial, antioxidant, and antiinflammatory properties (Silva et al, 2021). Studies have demonstrated that adding thyme essential oil/extract to fish feed can improve growth performance, antioxidant capacity, immune function, and resistance against diseases, including Aeromonas septicemia (Navarrete et al, 2010;Hoseini and Yousefi, 2019;Zargar et al, 2019;Khalil et al, 2020;Ghafarifarsani et al, 2022). One of the limitations of using essential oils in aquaculture is their stability, high light sensitivity and strong organoleptic characteristic (Luis et al, 2019).…”

Comparative Effect of the Active Substance of Thyme with N‐Acetyl Cysteine on Hematological Parameters and Histopathological Changes of Bone Marrow and Liver in Rat Models of Acetaminophen Toxicity

“…Thyme is one of the medicinal plants with significant antioxidant properties [ 46 ]. Besides, thymol and carvacrol, as important antioxidant components of the extract, are monoterpenes whose effects are not dose-dependent [ 47 ]. Therefore, it is necessary to use and determine the effective dose in this regard [ 48 ].…”