Impact of pyrethroids and organochlorine pesticides residue on IGF-1 and CYP1A genes expression and muscle protein patterns of cultured Mugil capito.

This study aimed to assess the levels of pyrethroids and organochlorine residues in the tissues of cultured Mugil capito and in water samples obtained from three different sites (Al-Hamol, Al-Riad and Sidi Salem; referred to as Area 1, Area 2, and Area 3, respectively) in the Delta region, Egypt. The study also assessed the biochemical markers in exposed mullet and evaluated the impact of these residues on the expression of insulin-like growth factor 1 (IGF-1) in muscle and cytochrome P4501A (CYP1A) in liver tissues using qRT-PCR and SDS-PAGE methods. The results revealed that pesticide residue levels in the water were variable, but were lower than detected levels in fish. Significant (P < 0.05) differences were found across the three study areas in terms of serum ALT, but the serum AST level was not significantly (P > 0.05) elevated in all study regions. Serum creatinine and urea levels were significantly (P < 0.05) elevated in area 3. Furthermore, glutathione and malondialdehyde concentrations significantly increased (P < 0.05) in liver tissues in area 3. Using the qRT-PCR technique, the results revealed that the expression level of IGF-1 was most significant in area 3, while the expression level of CYP1A was most significant in area 1. The protein profile showed some differences in band numbers and molecular weights of protein bands across different regions. Overall, the alteration in biochemical parameters revealed pesticide interference with the metabolic processes of fish. Furthermore, the pesticide pollution had an effect on the expression of IGF-1 and CYP1A genes and led to changes in the protein profile. Therefore, these markers can be used to monitor fish distress following exposure to the pollutant.

Replacement of dietary fish oil with plant oils improves the immunological responses and the antioxidant status in Oreochromis niloticus exposed to suboptimal temperature.

Here, we investigated the effects of total dietary fish oil (FO) substitution with plant oil (PO) on hematological indices, immune status, antioxidant activity, IL1ß and TNF-α gene expression, and hypoxia stress resistance in Oreochromis niloticus at suboptimal temperatures. Fish (n = 360) were randomly divided into 12 circular fiberglass tanks (500 L; 3 replicates for each dietary group, 30 fish/replicate, 90 fish/group). The control group was fed a basal diet with FO as the lipid source. The CO, SFO, and LSO groups were fed a basal diet with complete replacement of FO with corn, sunflower, and linseed oils, respectively. After 4 weeks, no effects on hematological indices were observed in fish fed the experimental diets. The LSO and CO groups showed a significant increase in γ globulin levels. The highest levels of non-specific immune parameters, antioxidant activity, and IL-1ß and TNF-α gene expressions were recorded in the LSO group. The LSO group also exhibited good resistance to hypoxia stress. Therefore, the total dietary substitution of FO with PO (especially LSO and CO) is recommended as a valuable strategy to ameliorate the immunosuppressive effects of suboptimal temperatures and enhance the resistance of O. niloticus to hypoxia stress.

Ziziphus mauritiana supplementation of Nile tilapia (Oreochromis niloticus) diet for improvement of immune response to Aeromonas hydrophila infection.

This study evaluated the effectiveness of dietary Ziziphus mauritiana leaf powder (ZLP) to control Aeromonas hydrophila infection in Nile tilapia and reduce damage to vital immune organs. Four experimental groups were fed a diet supplemented with ZLP at concentrations of 0, 5, 10, and 20 g/kg (w/w) for 6 weeks. At the end of the feeding trial, all groups were intraperitoneally injected with pathogenic A. hydrophila. It was found that Z. mauritiana significantly (P < 0.05) upregulated (lysozyme, interleukin 1 beta) and superoxide dismutase gene expressions as well as improved the activity of serum lysozyme and liver antioxidant enzymes. The fish that were fed a ZLP-supplemented diet also exhibited significantly higher survival rates after A. hydrophila challenge than those that were fed a ZLP-free diet (P < 0.05). Supplementation of 10 g/kg ZLP most effectively reduced the histopathological alterations caused by A. hydrophila challenge in the liver, spleen, kidney, and muscle of the fish. In conclusion, ZLP can be effective in controlling A. hydrophila infection in Nile tilapia (particularly at a concentration of 10 g/kg) through enhancement of its immune and antioxidant status.

Honey bee pollen improves growth, immunity and protection of Nile tilapia (Oreochromis niloticus) against infection with Aeromonas hydrophila.

The mode of action of honey bee pollen (HBP) was investigated in Nile tilapia (Oreochromis niloticus) challenged with Aeromonas hydrophila. Thus, fish with an average weight of 29 ± 3 g were divided into four groups, and fed with HBP-free diet (control), and 1%, 2.5% and 4% (w/v) HBP incorporated into basal diet for 10, 20 and 30 days. Immunological, hematological, biochemical and growth parameters were measured, and sub-groups of fish were challenged with A. hydrophila via intraperitoneal injection. HBP significantly increased the growth performance parameters [body weight, length, average daily gain (ADG), specific growth rate (SGR), and feed efficiency ratio (FER)] and immunological (phagocytic activity, serum bactericidal activity and nitroblue tetrazolium assay (NBT)), hematological (hematocrit (Hct), leucocrit (Lct), the numbers of neutrophils, monocytes and lymphocytes) and biochemical parameters (serum total protein, albumin and globulin ratios). Furthermore, all treated fish exhibited significant protection against challenge with A. hydrophila, with the highest protection (93%) observed in the group fed with 2.5% (w/v) HBP for 20 and 30 days.

Effects of dietary fermented Saccharomyces cerevisiae extract (Hilyses) supplementation on growth, hematology, immunity, antioxidants, and intestinal health in Nile tilapia.

This study investigated the effects of dietary supplementation with the product Hilyses on growth performance, feed utilization, nutrient composition, hematological parameters, serum biochemistry, immune function, antioxidant status, and digestive enzyme activity in juvenile Nile tilapia (Oreochromis niloticus, initial body weight 4.24 ± 0.01 g). The fish were fed diets supplemented with Hilyses at concentrations of 0, 1, 2, or 3 g/kg for a period of 8 weeks. The results showed that supplementation with Hilyses at levels up to 2 g/kg diet significantly improved final body weight, weight gain, specific growth rate, feed efficiency ratio, protein efficiency ratio, apparent protein utilization, and energy utilization compared to the control diet without Hilyses. Carcass crude protein content and moisture were significantly higher in Hilyses-fed groups, while crude lipid content decreased at the 3 g/kg supplementation level. Hilyses supplementation enhanced various hematological parameters, including increased red blood cell count, total leukocyte count, hemoglobin concentration, hematocrit, and mean corpuscular volume. Serum biochemistry and immune function markers like total protein, albumin, complement component C3, IgM, and IgG were significantly elevated in the 2 and 3 g/kg Hilyses groups. Antioxidant enzyme activities (catalase, glutathione peroxidase, total superoxide dismutase) were enhanced, and lipid peroxidation was reduced, in the 2 g/kg Hilyses group. Digestive enzyme activities, particularly protease and lipase, were also improved with Hilyses supplementation. Histological examination showed reduced lipid deposition in the liver and increased branching of intestinal villi at the 2 g/kg Hilyses level. Overall, these results indicated that dietary Hilyses supplementation at 2 g/kg diet optimizes growth, feed utilization, nutrient composition, hematology, immunity, antioxidant status, and digestive function in juvenile Nile tilapia.

Antiparasitic and Antibacterial Functionality of Essential Oils: An Alternative Approach for Sustainable Aquaculture.

Using synthetic antibiotics/chemicals for infectious bacterial pathogens and parasitic disease control causes beneficial microbial killing, produces multi-drug resistant pathogens, and residual antibiotic impacts in humans are the major threats to aquaculture sustainability. Applications of herbal products to combat microbial and parasitic diseases are considered as alternative approaches for sustainable aquaculture. Essential oils (EOs) are the secondary metabolites of medicinal plants that possess bioactive compounds like terpens, terpenoids, phenylpropenes, and isothiocyanates with synergistic relationship among these compounds. The hydrophobic compounds of EOs can penetrate the bacterial and parasitic cells and cause cell deformities and organelles dysfunctions. Dietary supplementation of EOs also modulate growth, immunity, and infectious disease resistance in aquatic organisms. Published research reports also demonstrated EOs effectiveness against Ichthyophthirius multifiliis, Gyrodactylus sp., Euclinostomum heterostomum, and other parasites both in vivo and in vitro. Moreover, different infectious fish pathogenic bacteria like Aeromonas salmonicida, Vibrio harveyi, and Streptococcus agalactiae destruction was confirmed by plant originated EOs. However, no research was conducted to confirm the mechanism of action or pathway identification of EOs to combat aquatic parasites and disease-causing microbes. This review aims to explore the effectiveness of EOs against fish parasites and pathogenic bacteria as an environment-friendly phytotherapeutic in the aquaculture industry. Moreover, research gaps and future approaches to use EOs for sustainable aquaculture practice are also postulated.

Molecular cloning and characterization of the nitric oxide synthase gene from kuruma shrimp, Marsupenaeus japonicus.

Nitric oxide (NO) signaling is involved in many physiological processes in vertebrates and invertebrates. In crustaceans, nitric oxide synthase (NOS) plays a significant role in the regulation of the nervous system and in innate immunity. Here, we describe the entire cDNA sequence (4616 bp) of the kuruma shrimp Marsupenaeus japonicus NOS (Mj NOS) generated using the reverse transcriptase-polymerase chain reaction (RT-PCR) and 5'- and 3'- rapid amplification PCRs of cDNA ends from brain and gill mRNAs. The open reading frame of Mj NOS encoded a protein of 1187 amino acids with an estimated mass of 134 kDa, and had an 82.3% sequence homology with the NOS gene of the land crab Gecarcinus lateralis. Highly conserved amino acid sequences in heme and tetrahydrobiopterin were observed in the oxygenase domain. FMN, FAD and NADPH were found in the reductase domain. Mj NOS mRNA was constitutively expressed in the brain, gill, intestine, thoracic ganglion and testis of the kuruma shrimp. When Vibrio penaeicida was injected into the kuruma shrimp, Mj NOS was expressed in the brain, gill, heart, lymphoid organ, intestine and thoracic ganglion. Mj NOS expression in the gill reached its peak 12 h and decreased to its normal level 24 h after V. penaeicida injection.

Miswak (Salvadora persica) modulated the growth performance, antioxidative response, and histopathological damage induced by zinc toxicity in Nile tilapia (Oreochromis niloticus).

In this study, Nile tilapia fingerlings with average body weight (8.6 ± 0.06 g) were exposed to zinc (Zn) toxicity and tested its amelioration with miswak (Salvadora persica L.) (SP) supplemented diet. Five fish groups were fed on diets with SP at 0, 0.25, 0.5, 1.0, and 2.0% (T1, T2, T3, T4, and T5, respectively) diet without Zn exposure, while another five groups were exposed to Zn at 7 mg/L and co-supplemented with SP at 0, 0.25, 0.5, 1.0, and 2.0 % (T6, T7, T8, T9, and T10, respectively). After 12 weeks, fish-fed 1.0% SP diet (T4) achieved the highest growth and feed performances, while the lowest one was in Zn-exposed fish (T6) (P < 0.05). T6 and T7 groups showed the most inferior carcass protein and ash contents, while T4 and T5 showed the highest lipid content (P < 0.05). The level of Zn residue increased in fish exposed to Zn (P < 0.05). Fish exposed to Zn and fed SP showed high blood urea, catalase, ALT, AST, and total superoxide dismutase (T-SOD), while the malondialdehyde (MDA) was decreased (P < 0.05). Interestingly, miswak resulted in elevated catalase and T-SOD and reduced MDA in fish without Zn exposure (P < 0.05). Zn exposure causes abnormal histopathological characteristics in gills, hepatopancreas, posterior kidney, and musculature tissues of tilapia, while fish-fed SP showed regular, healthy, and protected histopathological characters. The results suggested that SP can induce the antioxidant responses that prepare Nile tilapia for a further suppressive oxidative condition (i.e., Zn exposure).

Thermal stress accelerates mercury chloride toxicity in Oreochromis niloticus via up-regulation of mercury bioaccumulation and HSP70 mRNA expression.

Mercury (Hg) is an environmental pollutant that threatens aquatic life. Many environmental factors, including water temperature, are reported to influence the toxicity of dissolved chemicals in the aquatic ecosystem. Therefore, we investigated the impact of thermal stress on Hg-induced subchronic toxicity in Nile tilapia (Oreochromis niloticus). Fish were randomly allocated into five groups. Group I served as the control and kept at 25 °C. Groups II, III, IV, and V were reared at 25, 28, 31, and 34 °C, respectively, and co-exposed to HgCl2 (1/10 LC50) for 42 days. Blood and tissue samples were collected after 21 and 42 days. All HgCl2-exposed groups exhibited significant elevations in serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, and creatinine, along with decreases in the serum total protein and albumin. In addition, marked reductions in antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSPx), were observed. Remarkable increases in Hg tissue concentrations were detected along with increases in heat shock protein (HSP) 70 mRNA expression. Interestingly, the patterns data that were recorded were more coincident with the water temperature than the period of exposure. In conclusion, water temperature and exposure period are two crucial factors modulating HgCl2-induced toxicity and bioaccumulation in Nile tilapia. Our findings provide new insights concerning the impact of thermal stress as an environmental factor on Hg toxicity and bioaccumulation in Nile tilapia and, in turn, on fish and fish consumer health.

Modulation of genotoxicity and endocrine disruptive effects of malathion by dietary honeybee pollen and propolis in Nile tilapia (Oreochromis niloticus).

The present study aimed at verifying the usefulness of dietary 2.5% bee-pollen (BP) or propolis (PROP) to overcome the genotoxic and endocrine disruptive effects of malathion polluted water in Oreochromis niloticus (O. niloticus). The acute toxicity test was conducted in O. niloticus in various concentrations (0-8 ppm); mortality rate was assessed daily for 96 h. The 96 h-LC50 was 5 ppm and therefore 1/5 of the median lethal concentration (1 ppm) was used for chronic toxicity assessment. In experiment (1), fish (n = 8/group) were kept on a diet (BP/PROP or without additive (control)) and exposed daily to malathion in water at concentration of 5 ppm for 96 h "acute toxicity experiment". Protective efficiency against the malathion was verified through chromosomal aberrations (CA), micronucleus (MN) and DNA-fragmentation assessment. Survival rate in control, BP and PROP groups was 37.5%, 50.0% and 100.0%, respectively. Fish in BP and PROP groups showed a significant (P < 0.05) reduction in the frequency of CA (57.14% and 40.66%), MN (53.13% and 40.63%) and DNA-fragmentation (53.08% and 30.00%). In experiment (2), fish (10 males and 5 females/group) were kept on a diet with/without BP for 21 days before malathion-exposure in water at concentration of 0 ppm (control) or 1 ppm (Exposed) for further 10 days "chronic toxicity experiment". BP significantly (P < 0.05) reduced CA (86.33%), MN (82.22%) and DNA-fragmentation (93.11%), prolonged the sperm motility when exposed to 0.01 ppm of pollutant in vitro and increased the estradiol level in females comparing to control. In conclusion, BP can be used as a feed additive for fish prone to be raised in integrated fish farms or cage culture due to its potency to chemo-protect against genotoxicity and sperm-teratogenicity persuaded by malathion-exposure.