Exploring Antimicrobial Potential of Cinnamon, Clove, Peppermint and Black Cumin Essential Oils against Fish Bacterial Pathogens with an Emphasis on the Dietary Supplementation Effects of Cinnamon Oil on Striped Catfish (Pangasianodon hypophthalmus)

Emergence of antimicrobial resistance (AMR) among fish bacterial pathogens is one of the major global public threats. Attempts are being made to develop novel alternatives as a promising approach to combat multidrug resistance disease-causing bacteria. Natural antimicrobials such as essential oils (EOs) are a potential unique strategy to treat bacterial infections with a reduced risk of resistance developing. This study aimed to evaluate the antimicrobial activity of some essential oils (EOs) namely, cinnamon (Cinnamomum zeylanicum), clove (Syzygium aromaticum), Peppermint (Mentha piperita) , and black cumin (Nigella sativa) against some fish pathogens implicated with aquaculture disease outbreaks like Aeromonas hydrophilia, Pseudomonas fluorescence, Photobacterium damselae and Streptococcus agalactiae using agar well diffusion assay. We found significant differences on the antibacterial activity depending on the type of essential oils and bacterial strain. Among all the tested EOs, cinnamon essential oil (CEO) was shown to be the most effective with minimum bactericidal concentration (MBC) ranged from 0.0156-0.125 ml/ml. As a result, it was selected for our in vivo investigations. We next aimed to investigate the effects of dietary CEO on growth performance, disease resistance and immune response of fish. A total of 150 striped catfish (Pangasianodon hypophthalmus) were fed with different levels of CEO (0, 1.50, 2.0, 2.50, and 3.0 mL/kg diets) (assigned as control, Diet 1, Diet 2, Diet 3 and Diet 4) for 60 days. Compared to control, fish fed with graded levels of dietary CEO showed significant (P < 0.05) increase in final body weight, weight gain %, and specific growth rate particularly at fish group fed diet 3. Of interest, there were no significant differences (P > 0.05) in feed conversion ratio and survival rates among control and CEO-supplemented groups. Moreover, we found significant (P < 0.05) increases in plasma lysozyme activity and total IgM levels in a dose dependent manner with dietary CEO supplementation. After feeding trials, we investigated their potential to defend striped catfish against A. hydrophila challenge. Fish fed control diet had the highest mortality rates; in contrast, fish fed diets supplemented with CEO had higher levels of resistance to the bacterial infection, with the lowest mortality rates in the fish group fed diet 3. Overall, these findings showed that EOs exhibit a great potential to be used as antimicrobial agents against fish pathogens. Moreover, dietary administration of CEO, particularly at 2.5 ml/kg feed, can be regarded as a promising component for improving growth, immunological responses and potential alternatives to conventional antimicrobials for control of microbial infections in fish

Spirulina platensis mediated the biochemical indices and antioxidative function of Nile tilapia (Oreochromis niloticus) intoxicated with aflatoxin B1

International audienceAflatoxicosis is one of the threats that cause severe mortalities in fish farms. The dietary functional additives are a friendly approach attributed to beneficial effects on aquatic animals. The study aimed at evaluating the impact of Spirulina platensis (SP) on the biochemical indices and antioxidative function of Nile tilapia (Oreochromis niloticus) intoxicated with aflatoxin B1 (AFB1). A control diet and 3 test diets were enriched with 0% SP/0 mg AFB1/kg (control), 1% SP (SP), 2.5 mg AFB1/kg diet (AFB1), and 1% SPþ2.5 mg AFB1/kg diet (SP/AFB1). The diets were supplied to three aquaria for each group twice daily at the rate of 2.5% for 30 days. The blood alanine transaminase (ALT), alkaline phosphatase (ALP), and aspartate transaminase (AST) were significantly increased by AFB1 toxicity with regards to fish fed the control and SP diets (P < 0.05). The inclusion of SP in the diet of tilapia intoxicated with AFB1 lowered the levels of ALT, AST, and ALP in comparison to fish contaminated with AFB1without SP (P < 0.05). The total blood protein and albumin were decreased in fish contaminated with AFB1 (P < 0.05); however, the dietary SP resulted in improving the blood protein and albumin with similar levels with the control and SP diets. The urea and creatinine were increased in tilapia fed AFB1 diet without SP (P < 0.05); however, the inclusion of SP reduced the levels of urea and creatinine with similar levels with the control and SP diets. The antioxidative capacity of Nile tilapia fed SP and contaminated with AFB1 is expressed by superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) concentration. The activities of SOD and GSH were decreased by AFB1 (P < 0.05); however, dietary SP increased the SOD and GSH in fish fed AFB1. On the other hand, the concentration of MDA was increased in tilapia fed AFB1 (P < 0.05); however, SP decreased the level of MDA in fish fed AFB1. In conclusion, the application of SP in the aquafeed seems to be an innovativeapproach to relieve the toxic influences of AFB1 on aquatic animals

Hazardous Effects of SiO₂ Nanoparticles on Liver and Kidney Functions, Histopathology Characteristics, and Transcriptomic Responses in Nile Tilapia (<i>Oreochromis niloticus</i>) Juveniles

The current investigation assessed the impacts of sub-lethal concentrations of silicon dioxide nanoparticles (SiO2NPs) on hepato-renal functions, histopathological characteristics, and gene transcription in gills and liver of Nile tilapia juveniles. Fish were exposed to 20, 40, and 100 mg/L of SiO2NPs for 3 weeks. Pairwise comparisons with the control group showed a significant dose-dependent elevation in serum ALP, ALT, and AST enzyme activities as well as blood urea and creatinine levels in SiO2NP-intoxicated groups. Exposure to 100 mg/L SiO2NPs significantly upregulated expression of HSP70, TNF-α, IL-1β, and IL-8 genes in the gills as compared to the control group. Moreover, exposure to 100 mg/L SiO2NPs significantly upregulated the expression SOD, HSP70, IL-1β, IL-8, and TNF-α genes in the hepatic tissues as compared to the control group. Exposure of fish to 20 mg SiO2NPs/L significantly increased the mRNA expression levels of IL-12 in both the gills and liver tissues. Notably, all tested SiO2NP concentrations significantly upregulated the transcription of CASP3 gene in gills and liver of Nile tilapia as compared to the control group. Interestingly, varying histopathological alterations in renal, hepatopancreatic, and branchial tissues were observed to be correlated to the tested SiO2NP concentrations. In conclusion, our results provide additional information on the toxic impacts of SiO2NPs in Nile tilapia at the hematological, tissue, and molecular levels

Selenium nanoparticles as a natural antioxidant and metabolic regulator in aquaculture: A review

Balanced aquafeed is the key factor for enhancing the productivity of aquatic animals. In this context, aquatic animals require optimal amounts of lipids, proteins, carbohydrates, vitamins, and minerals. The original plant and animals’ ingredients in the basal diets are insufficient to provide aquafeed with suitable amounts of minerals. Concurrently, elements should be incorporated in aquafeed in optimal doses, which differ based on the basal diets’ species, age, size, and composition. Selenium is one of the essential trace elements involved in various metabolic, biological, and physiological functions. Se acts as a precursor for antioxidative enzyme synthesis leading to high total antioxidative capacity. Further, Se can enhance the immune response and the tolerance of aquatic animals to infectious diseases. Several metabolic mechanisms, such as thyroid hormone production, cytokine formation, fecundity, and DNA synthesis, require sufficient Se addition. The recent progress in the nanotechnology industry is also applied in the production of Se nanoparticles. Indeed, Se nanoparticles are elaborated as more soluble and bioavailable than the organic and non-organic forms. In aquaculture, multiple investigations have elaborated the role of Se nanoparticles on the performances and wellbeing of aquatic animals. In this review, the outputs of recent studies associated with the role of Se nanoparticles on aquatic animals’ performances were simplified and presented for more research and development

The applications of cerium oxide nanoform and its ecotoxicity in the aquatic environment: an updated insight

The widespread usage of nanotechnology in many essential products has raised concerns about the possible release of nanoparticles (NPs) into aquatic habitats. Cerium dioxide (CeO2) has gained the most interest in the worldwide nanotechnology industry of all types of Ce minerals owing to its beneficial uses in a wide range of industry practices such as catalysts, sunscreens, fuel additives, fuel cells, and biomedicine. Besides, it was realized that CeO2 nanoparticles (n-CeO2) have multi-enzyme synthesized properties that create various biological impacts, such as effectively antioxidant towards almost all irritant intracellular reactive oxygen species. Lately, it was discovered that a large amount of n-CeO2 from untreated industrial waste could be released into the aquatic environment and affect all living organisms. In addition, the physical/chemical characteristics, fate, and bioavailability of nanomaterials in the aquatic environment were discovered to be related to the synthesis technique. Thus, there are intended needs in identifying the optimal technique of synthesized CeO2 nanoparticles in order to assess their beneficial use or their potential ecotoxicological impacts on aquatic organisms and humans. Therefore, this review sheds light on the possible threats of n-CeO2 to aquatic creatures as well as its synthesized techniques. Also, it discusses the possible mechanism of n-CeO2 toxicity as well as their potential benefits in the aquaculture industry

Marine-derived products as functional feed additives in aquaculture: A review

The aquaculture industry is expanding to meet the daily requirements of humanity from high-quality seafood. In this regard, intensive aquaculture systems are suggested, resulting in high production but being challenged with immunosuppression and disease invaders. Antibiotics were used for a long time to protect and treat aquatic animals; however, continuous use led to severe food safety issues, reducing the natural immunity response and high resistance to harmful bacterial strains. Therefore, natural functional additives were introduced to reduce or even replace chemotherapies. More specifically, marine-derived substances showed effective immunostimulant and antioxidative roles when introduced to aquatic animals. Bioactive molecules derived from algae, crustaceans, and fish, including astaxanthin, carotenoids, chitosan, fucoidan, lectins, and polyunsaturated fatty acids (PUFAs), are the most applied additives in aquaculture. In addition, marine-derived biomolecules were introduced to several other sectors, such as nutraceuticals, pharmaceuticals, cosmetics, and agriculture. Marine-derived substances are lipid-soluble biomolecules known for their ability to cross the cellular membranes, thereby causing pigmentation roles. Consequently, marine-derived biomolecules are involved in antioxidative and immune activation effects and, thereby, high performances and productivity of aquatic animals. In the literature, there are available knowledge about the possibility of using marine-derived biomolecules in aquaculture. This article presents information about the sources, mode of action, and effects of marine-derived biomolecules on aquatic animals to fortify the scientific community with enough details about friendly natural substances for sustainable aquaculture

Assessment of zootechnical parameters, intestinal digestive enzymes, haemato-immune responses, and hepatic antioxidant status of Pangasianodon hypophthalmus fingerlings reared under different stocking densities

A 3-month experiment was designed to investigate the effects of different stocking densities on growth, stress markers, intestinal digestive enzymes, hepatic antioxidant biomarkers, serum immunity, and survivability of striped catfish, Pangasianodon hypophthalmus. The relationship between fish stocking densities and water quality parameters was also assessed. Healthy fish (n = 1260 individuals, 17.52 ± 0.20 g) were raised in twelve fiberglass tanks. Triplicate fish groups with stocking densities of 60, 90, 120, or 150 fish per 1 m3 were designed, further referred to as SD60, SD90, SD120, and SD150 groups. Fish feeding was done using a commercially purchased well-balanced diet three times per day with a feeding rate of 3% of the wet fish weight. Results revealed that un-ionized ammonia, nitrite, and pH were significantly elevated, and dissolved oxygen levels were decreased significantly with increasing the stocking densities. The survival rates and growth significantly decreased with increasing fish stocking densities. The intestinal lipase, protease, trypsin, and amylase enzymes decreased significantly (P < 0.05) along with increased stocking densities. Moreover, significant decreases were noticed in total protein, lysozyme activity, and globulin levels when the stocking density was higher than 60 fish/m3. Conversely, serum stress biomarkers (such as blood glucose and cortisol), transaminases, alkaline phosphatase, and blood urea nitrogen were significantly elevated with increasing stocking densities. Hepatic CAT, SOD, and T-AOC were decreased; meanwhile, hepatic MDA levels were significantly increased, together with the stocking rates. In the end, we found that the SD150 group recorded the lowest growth rates, immune responses, and antioxidant capacity and the highest stress markers as blood glucose and cortisol. In this context, we can conclude that the stocking 60 fish/m3 resulted in better growth, survival, immunity, antioxidant status, and overall performances of striped catfish. Graphical Abstract: [Figure not available: see fulltext.]