جستجوی مقالات مرتبط با کلیدواژه « Fish » در نشریات گروه « شیلات »

Yersinia enterocolitica is the cause of yersiniosis in humans and its symptoms range from mild diarrhea to mesenteric lymphadenitis that may lead to appendicitis. In this study, the frequency and antibiotic resistance of Yersinia enterocolitica isolated from fish caught in Anzali wetland were investigated. Sampling was carried out for one year in four seasons from the autumn 2018 to the summer 2019 from four geographical directions: east, west, north and south, from different wetland levels. A total number of 91 fish were sampled from the body of these fish. Microbiological tests including biochemical tests, specific culture, and PCR were performed. In the specific culture method, 20 samples (21.97%) were contaminated with Yersinia enterocolitica. For the final confirmation of PCR, 20 samples were isolated from 14 samples (15.4%) containing specific culture method (6 Carp, 3 Anchovy, 0 Bream, 4 Pike Perch and 1 Pike) were infected with Yersinia enterocolitica. The chi-square test showed that there was no statistically significant difference between the various seasons (p >0.05), while there was a significant difference between fish species (p <0.05). Isolates from Yersinia enterocolitica using an antibiogram test of 10 antibiotics, the most susceptible isolates, Imipenem (92.8%), Kanamycin and Gentamicin (85.7%), Ceftazidime (78.57%). Cotrimoxazole and Nalidixic acid (71.4%) were the most resistant isolates to Ampicillin (64.28%), respectively. The results showed high levels of contamination of Yersinia enterocolitica, and indicative of potential dangers of Yersinia enterocolitica pathogenicity, especially in immunocompromised and susceptible individuals. Further studies on the pathogenicity of Yersinia enterocolitica in fish within the Anzali wetland and preventing sewage from entering the wetland are suggested.

Numerous techniques are used in aquaculture to stripped eggs from fish broodstocks. The most common is the manual method, where the abdomen of the fish is gently massaged to extract the eggs. Alternatively, injecting gas pressure into the abdominal cavity can facilitate the release of eggs with potentially fewer negative impacts on the welfare and egg quality. This study compared the pneumatic stripping methods and the manual spawning method in rainbow trout (Oncorhynchus mykiss) spawners. The study focused on the effects of these techniques on the quality of the harvested eggs, relative fertility, stripping duration, and pH of the ovarian fluids. The findings revealed that maintaining a gas flow rate at 1.5 L min-1 during stripping is crucial to prevent post-stripping mortality of the broodstocks. The pneumatic method demonstrated a shorter duration of egg retrieval (39.5 s) compared to the manual method (42 s). Notably, there were no significant differences observed in ovarian fluid pH across the various methods (p<0.05). Overall, pneumatic egg extraction leads to higher-quality eggs with a greater hatching rate compared to the manual method. Considering the positive results of the pneumatic stripping and its high level of repeatability and efficiency, it can be used instead of the traditional method in rainbow trout hatcheries.

About 100 C. luteus were examined to determine the extent of the presence of disease-causing bacteria in the Diwaniyah River from April 2021 to March 2022. The bacteria were isolated using the VITEK2 system, and vital tests identified the species Aeromonas hydrophila and Sphingobacterium thalpophilum. Aeromonas hydrophila and S. thalpophilum were tested in vitro, revealing noticeable antibiotic susceptibility. Levofloxacin (?0.22 ?g/ml for A. hydrophila and ?0.20 ?g/ml for S. thalpophilum), as well as Ciprofloxacin (?0.10 ?g/ml) and Imipenem (?0.23 ?g/ml), demonstrated notable effectiveness. Resistance to Cefazolin was observed in A. hydrophila (?69 ?g/ml) and S. thalpophilum (?70 ?g/ml). The study highlights the presence of harmful bacteria in C. luteus from the river, specifically A. hydrophila and S. thalpophilum. The findings emphasize the critical importance of prudent antibiotic use and ongoing monitoring in aquaculture practices to mitigate risks and safeguard public health.

Mangrove ecosystems all around the globe are affected by microplastic (MPs) pollution. The Sundarban Biosphere reserve, the world’s largest mangrove forest is not an exception. The study aims to identify the occurrence of MPs in the gastro-intestinal tract (GI tract) of estuarine fish from Indian Sundarbans and the relationship between the presence of MPs with the morphology and feeding niche of fish. Total of 13 fish species were collected from the Saptamukhi River near Lothian Island, India and MPs were isolated from GI tract contents. Morphological parameters like body size, mouth aperture length, eyeball diameter and GI tract length of fish were measured. Niche breadths and niche overlapping of these 13 species were analyzed using Levin niche breadth and Pianka niche-overlap indices. The fiber-shaped MPs were ubiquitously detected in all fish species followed by films and fragments. The size of MPs was ranged from 100µm to <5mm. A significant variation (p<0.0001) in respect of the trophic morphology of fish and length of MPs (p<0.05) were found. The length of MPs had a positive correlation with body size and mouth aperture but in the case of GI tract length and eyeball diameter, the correlation was negative. It was noticed that the presences of MPs in GI tract of those 13 estuarine fish species did not bother their niche breadth and niche overlap.

The presence of antibiotics in the aquatic environment poses great concerns due to their impact on water quality, aquatic organisms, and human health. The current study aims to detect the antibiotic residues (Amoxicillin (AMO), Ciprofloxacin (CIP), and Levofloxacin (LEV)) seasonally in the muscles and liver of Nile tilapia, Oreochromis niloticus, collected from Shatt Al-Arab and to know their effect on some health aspects of fish during November 2020 to August 2021 by selecting two stations in the river. The samples were analyzed using high-performance liquid chromatography (HPLC) for measuring antibiotics. The study revealed high concentrations of antibiotics in the muscles and liver of fish, and the concentrations were higher in the second station. CIP had the highest concentration (7.4 mg/kg) in muscles in the spring, and the AMO showed the highest concentration (4.1 mg/kg) in the liver during the spring. The study also showed that the accumulation of antibiotics in the liver and muscles of fish had negative effects on the health standards of fish. The presence of antibiotic residues in fish samples in high concentrations is a source of great concern as it is a major source of human food.

A study was conducted to determine the growth performance and bioaccumulation and tolerance of metal mixture toxins in five fish species including Labeo rohita, Catla catla, Cirrhina mrigala, Hypophthalmichthys molitrix and Ctenopharyngodon idella separately, under chronic exposure of metal mixture (Fe + Zn + Pb) at sub-lethal concentrations (1/3 of LC50) for 12 weeks period. Moreover, response of different body organs of fish towards bioaccumulation of metals under metals mixture stress was also determined. It was found that the relationships among growth parameters of metals mixture stressed as well as unstressed (control) fish were significantly different. Results showed that, the sub-lethal exposure of metals mixture induced substantial impacts on the wet weight gain (g) and length (mm) of fish species, with following trend; C. catla> C. idella> C. mrigala> L. rohita >H. molitrix. However, growth rate of fish under control treatment (no stress) was significantly higher compared to the fish exposed to metals mixture. It was also observed that the condition factor was positively correlated with fish growth and expressed the extent of fish well-beings. The bioaccumulation pattern in the body organs was observed with the following trend: liver> kidney> gills> skin> fins > muscles> bones. This study concluded that metal mixtures seriously affect the growth and development of aquatic organisms.

Metals are the major pollutants in aquatic environment. A lot of research literature is available globally about accumulation of heavy metals in aquatic ecosystems as well as in different body organs of aquatic animals, especially fish. Heavy metals mainly generate reactive oxygen species (ROS) in aquatic animals that lead to oxidative stress production. ROS cause oxidative damage to different animal tissues and cellular components, like protein and DNA. Aluminum exists in aquatic environments of Pakistan in concentration higher than permissible limits. So, the present study is conducted to determine toxic effects of aluminum on DNA in peripheral blood erythrocytes of fish viz., Cirrhinus mrigala and Ctenopharyngodon idella. For this purpose, fingerlings of each species were exposed to four sublethal concentrations of 17, 25, 33 and 50%. The effects of aluminum on 96-h LC50 concentrations were evaluated for a period of 30 days under controlled laboratory conditions. Results revealed significant toxic effect of this metal on genetic material of fish. Among the four treatments, 50% sublethal concentration 96-h LC50 of aluminum caused significantly higher percentage of DNA damage, genetic damage index and cumulative tail length of comets. Highest frequency of micronuclei was observed in 50% treatments of 96-hr LC50 exposure of aluminum which was not statistically (p<0.05) similar to micronuclei frequency caused by 33% of 96-hr LC50 of aluminum in fish. The findings of this experiment showed that aluminum exposure caused genetic damage in fish. Moreover, comet assay and micronucleus test appeared to be reliable indicators of metallic ion toxicity in aquatic animals.

Fingerlings of Catla catla were exposed to 1, 5, and 25 mg/L of zinc oxide nanoparticles (ZnO NPs) for 15 days, and specific hematological and biochemical parameters were evaluated to assess the toxicity. During the exposure period, red blood cell (RBC) count was found to decrease (except at the end of the 5th day in 1 mg/L) whereas white blood cell (WBC) count was found to increase in ZnO NPs treated fishes. A significantly higher hematocrit (Hct) level was recorded in fish exposed to 1 mg/L when compared with control and a higher concentration of ZnO NPs (5 and 25 mg/L). Erythrocyte indices such as mean cellular volume (MCV) and mean cellular hemoglobin (MCH) values (except at the end of 5 and 10th day at 1 and 10 mg/L exposed groups) were significantly increased. Mean cellular hemoglobin concentration (MCHC) level was found to be increased at 1 and 25 mg/L treated groups compared to 10 mg/L. Compared to the control group, plasma glucose level was increased significantly in fish exposed to 5 and 25 mg/L concentrations of ZnO NPs, while the plasma glucose level was decreased at the end of the 15th day in all the concentrations. Plasma protein level was increased at the end of the 5th day while the level of plasma protein was decreased on the 10 and 15th day. A significant increase in glutamate oxaloacetate transaminase (GOT) (except at the end of 10th day) and glutamate pyruvate transaminase (GPT) activity in gill and liver (except at the end of 10 and 15th day in gill) were noted in all the concentrations tested when compared to control groups. The results of the present study indicate that ZnO NPs at 1, 5, and 25 mg/L can alter the hematological and biochemical parameters of fish and the toxicity data may provide the ecotoxicological impact of ZnO NPs on the aquatic environment.