Exploring the Interactive Effects of Thymol and Thymoquinone: Moving towards an Enhanced Performance, Gross Margin, Immunity and Aeromonas sobria Resistance of Nile Tilapia (Oreochromis niloticus)

Abstract

Plant-derived bioactive compounds with promising nutritional and therapeutic attributes (phytogenics) are among the top priorities in the aquaculture sector. Therefore, the impact of thymol (Thy) and/or thymoquinone (ThQ) on the growth, immune response antioxidant capacity, and Aeromonas sobria (A. sobria) resistance of Nile tilapia was investigated. Four fish groups were fed a control diet and three basal diets supplemented with 200 mg/kg diet of Thy or ThQ and a blend of both Thy and ThQ at a level of 200 mg/kg diet each. At the end of the feeding trial (12 weeks), the tilapias were challenged intraperitoneally with virulent A. sobria (2.5 × 108 CFU/mL) harboring aerolysin (aero) and hemolysin (hly) genes. The results revealed that tilapias fed diets fortified with a combination of Thy and ThQ displayed significantly enhanced growth rate and feed conversion ratio. Notably, the expression of the genes encoding digestive enzymes (pepsinogen, chymotrypsinogen, α-amylase and lipase) and muscle and intestinal antioxidant enzymes (glutathione peroxidase, catalase and superoxide dismutase) was significantly upregulated in Thy/ThQ-fed fish. An excessive inflammatory response was subsided more prominently in the group administrated Thy/ThQ as supported by the downregulation of il-β, il-6 and il-8 genes and in contrast, the upregulation of the anti-inflammatory il-10 gene. Remarkably, dietary inclusion of Thy/ThQ augmented the expression of autophagy-related genes, whilst it downregulated that of mtor gene improving the autophagy process. Furthermore, Thy/ThQ protective effect against A. sobria was evidenced via downregulating the expression of its aero and hly virulence genes with higher fish survival rates. Overall, the current study encouraged the inclusion of Thy/ThQ in fish diets to boost their growth rates, promote digestive and antioxidant genes expression, improve their immune responses and provide defense against A. sorbia infections with great economic benefits.

Liposomal encapsulated oregano, cinnamon, and clove oils enhanced the performance, bacterial metabolites antioxidant potential, and intestinal microbiota of broiler chickens

“…In this regard, herein, dietary inclusion of LEOs significantly increased the expression levels of genes encoding gut barrier functions and TJP (MUC-2, JAM-2, and occludin) in broilers, suggesting its promising role in maintaining the gastrointestinal barrier functions. In agreement with our results, previous studies stated that encapsulated carvacrol and thymol mixture, oregano EO ( Liu et al, 2019 ), carvacrol and thymol mixture, and a mixture of carvacrol, trans-cinnamaldehyde and thymol EOs ( Aljazzar et al, 2022 ; Ibrahim et al, 2022b ) had provoked the expression level of occludin gene in broilers. Similarly, recent studies reported that the expression levels of MUC-2, JAM-2, and occludin genes were upregulated following dietary inclusion of eugenol nanoemulsion ( Ibrahim et al, 2022a ), thymol nanoemulsion ( Ibrahim et al, 2021a ), garlic nanohydrogel, and blend of EOs ( Aljazzar et al, 2022 ) in broilers.…”

“…In line with the provoked nutrient digestibility and digestive enzymes` activities in LEOs-supplemented groups, the transcription levels of genes encoding digestive enzymes (AMY2A, CCK, and PNLIP) were also elevated. The synthesis of digestive enzymes can be altered by hormones, genes, and dietary feed supplements ( Ibrahim et al, 2022b ). Furthermore, the upregulation of genes encoding digestive enzymes reflected the significant role of specific nutritional aids or even their adaptations by animals ( Zhang et al, 2021 ).…”

“…Modern fast-growing broilers are more susceptible to oxidative stress, which impairs their physiological processes and immune response ( Ibrahim et al, 2021b , f ) with bad consequences of inferior quality of their products together with higher incidence of bacterial diseases ( Zhou et al, 2019 ; Ibrahim et al, 2021e , 2022b ). The threats of bacterial infection are mainly contributed to extensive usage of antimicrobial agents in animals and humans, particularly in developing countries ( Abd El-Hamid et al, 2019 ; Ammar et al, 2021c ), which seriously affects the emergence of multidrug-resistant bacteria ( Zhu et al, 2021 ; Ammar et al, 2021b , 2022 ; Awad et al, 2022 ; Bendary et al, 2022 ).…”

“…Therefore, the application of novel alternative antimicrobials from herbal medicine with antimicrobial, antioxidant and growth-promoting characteristics is urgently needed to overcome the above-mentioned adverse issues ( Ibrahim et al, 2020 , 2021c , 2022a ; Ammar et al, 2021a ). Phytochemicals as plants secondary metabolites have proven to possess growth-enhancing, antimicrobial, antioxidant, anti-inflammatory, and immunostimulant activities via minimizing the bacterial loads and modifying the expression levels of antioxidant and immune-related genes ( Ammar et al, 2021b ; Ibrahim et al, 2022b ). These beneficial activities are attributable to the existence of several bioactive compounds including essential oils, EOs ( Elmowalid et al, 2019 ; Hashem et al, 2022 ).…”

A new pathogenic isolate of Kocuria kristinae identified for the first time in the marine fish Larimichthys crocea

“…in seabreams; furthermore, the fungal pathogens Saprolegnia spp. and the parasites Trichodina , Chilodonela , Argulus , and Ergasilus , as well as Leeches have been known for a long time ( Kim et al, 2017 ; Buján et al, 2018 ; Duman et al, 2021 ; Abd El-Hack et al, 2022 ; Shahin et al, 2022 ; Ibrahim et al, 2022a , b ). However, many unknown or emerging etiological diseases still appear frequently in aquatic farms, seriously affecting the development of aquaculture ( Shahin et al, 2022 ).…”