Growth performance, immune response and disease resistance of rainbow trout (Oncorhynchus mykiss) fedThymus vulgarisessential oils

Abstract

Efficacy of Thymus vulgaris essential oils was assessed on growth, immune response and disease resistance of rainbow trout (Oncorhynchus mykiss). Fish weighing 10 g were fed with dietary supplemented of the oils at 0.5, 1.0 and 2.0 ml/kg feed for 2 months. Fish fed with the oils at 0.5 ml/kg feed demonstrated a better weight gain and specific growth rate, compared to other treatments (p < .05). Fish fed with 1.0 ml the oils showed the highest up‐regulation of complement component 3 (C3) and (cluster of differentiation 4) (CD4) genes expression (p < .05), while lysozyme gene expression level significantly increased in fish fed with 2.0 ml of the oils. In addition, at the end of the experiment, the expression of C3 and CD4 genes were significantly up‐regulated in fish fed with 1.0 and 2.0 ml of the oils, while IL‐1ß and lysozyme genes expression levels were significantly decreased in fish fed 2.0 ml oils, towards the end of the trial (p < .05). There was a fluctuation in the levels of Alanine aminotransferase, Aspartate aminotransferase and Alkaline phosphatase in all treatments during the experiment. When treated fish were challenged with Aeromonas hydrophila, the highest survival rate was observed in 0.5 ml/kg treatment, followed by 2 and 1 mg/kg treatments. Overall, these findings demonstrated that dietary administration of T. vulgaris oils especially at 0.5 mg/kg feed can be considered as a potential component for enhancing of the growth, immune responses and disease resistance of trout against motile Aeromonas septicemia caused by A. hydrophila.

The effect ofLavandula officinalisnanoemulsion on growth performance, body composition, haematology and immunity parameters ofOncorhynchus mykiss

“…Medicinal plants could be used as stimulants of growth and immunity in aquaculture (Kirubakaran et al 2010). In recent years, more studies confirmed the positive effects of herbal medicines such as Quercus brantii (Rashidian et al 2018), Rhodomyrtus tomentosa (Na-Phatthalung et al 2018), Stachys lavandulifolia (Moghanlou et al 2018), Coriandrum sativum (Farsani et al 2019), Aloe barbadensis (Mehrabi et al 2019), Pandanus tectorius (Awad et al 2019) and Thymus vulgaris (Zargar et al 2019) on the growth of rainbow trout, physiology and immunity parameters. L. officinalis is a plant medicine of family Lamiaceae and has long been used as antibacterial, antifungal and antidepressant (Nikfarjam et al 2017).…”

The Effects of Oral Rehmannia glutinosa Polysaccharide Administration on Immune Responses, Antioxidant Activity and Resistance Against Aeromonas hydrophila in the Common Carp, Cyprinus carpio L

“…Therefore, the LZM and AKP activities in serum were detected at the end of the experiment. Several immunostimulants (such as Thymus vulgaris essential oils, Sargassum horneri, and Psidium guajava) reportedly enhance the LZM and AKP levels in fish (70)(71)(72). For example, the inclusion of Heracleum persicum and Myrtle (Myrtus communis L., Myrtaceae) in the diet significantly elevated the LZM activity in the common carp (73) and zebrafish (62), respectively, and oral exopolysaccharide from Lactococcus lactis Z-2 significantly up-regulated the LZM and AKP activities in common carp (74).…”

A review on the beneficial effect of thymol on health and production of fish

“…In contrast, a study of Hoseini and Yousefi (2018) confirmed the non-significant impacts on growth performance parameters, that is final weight and weight gain, feed efficiency by feeding rainbow trout on thyme extracts. Recently, thymol oil supplemented at 0.5 mg kg À1 feed to rainbow trout basal diet lead to enhance the weight gain, length gain and specific growth rate by 30.9%, 12.6% and 18.36%, respectively, compared with the control group (Zargar et al 2019). Authors suggested that thyme could improve the metabolism and absorption of the nutrients in the gut, and thus has the ability to lowering the prevalence of mortalities and disease via the both antibacterial action in the gastrointestinal tract in fish.…”

“…Blood profile and components are considered important indicators of fish tissue health. It has been reported that the addition of thymol oil to the rainbow trout diet had a significant reduction in alkaline phosphatase and aspartate transaminase (AST) levels, but alanine transaminase (ALT) level did not exhibit any significant effect (Zargar et al 2019). Valladão et al (2019) clarified that the addition of 1% thyme oil in the Nile tilapia diets increased significantly lymphocytes and leucocytes counts; however, no significant effect was detected in the majority of blood biochemical like total protein, albumin, globulin, and ALT and AST levels.…”

“…Use of EOs in germ-free zebrafish at 2 and 20 mg L À1 for one day upregulated the expression of interleukin-1b (Il1b) and Claudin1, respectively (Ran et al 2016). Zargar et al (2019) noticed that a significant upregulation in immune-related genes expression such as complement component 3 and cluster of differentiation 4, lysozyme and interleukin-1 beta when thymol oil was added to the rainbow trout basal diet compared with the control group. Supplementation of 1% thyme as a feed additive for 45 days improved lysozyme and phagocytic activities as well as immunocompetent cell population (G€ ultepe et al 2014).…”