The paper aimed to investigate the concentration variations and evaluate the bioaccumulation as well as the health risk of Cr, Ni, Cu, Zn, As, Cd and Pb in the aquaculture pond ecosystem during a complete breeding cyc...The paper aimed to investigate the concentration variations and evaluate the bioaccumulation as well as the health risk of Cr, Ni, Cu, Zn, As, Cd and Pb in the aquaculture pond ecosystem during a complete breeding cycle. The samples of water, sediment and aquatic organisms were collected from the pond of gull island in the Pearl River Delta, China. In the breeding cycle, the results revealed the metal concentration in the water increased, while the sediment metal concentration showed no significant difference. The heavy metal concentrations in the water were higher than the background values (December 2017) which related to the input of feeds. Sediment metal concentrations (Cr, Ni, Cu, Zn, As and Cd) in the sediment were higher than the background values of Guangdong Province, China, indicating these metal pollutions came from anthropogenic activities. While the concentration of Pb was comparable to the background value, implying that the Pb was mainly from the earth crust. In addition, various metals showed different affinity to fish organs (muscle, skin, bladder, gill, heart, kidney and liver). Zinc was abundant in skin, while As and Cd concentrations were highest in kidneys;Cu was accumulated highest in liver;Cr concentrations was highest in hearts;and Ni was mainly found in bladders, and the Pb was most commonly found in gills. The distribution of heavy metals in the tissues organs was in the sequence of: Zn > Cu > Cr > Ni > Pb > As > Cd. As the fish ages, the Cu and Zn concentration in tissue organs declined, while the Cr, Ni, As, Cd and Pb increased slightly. Estimations of health risks showed no evidence of potential threats to consumers.展开更多
Fishes are cheap sources of protein and are commonly reared in artificial pond in Nigeria. Bacterial infested fishes have been a serious public health concern. This study was aimed at isolating and identifying bacteri...Fishes are cheap sources of protein and are commonly reared in artificial pond in Nigeria. Bacterial infested fishes have been a serious public health concern. This study was aimed at isolating and identifying bacteria associated with the internal organs (gills, liver, guts) of <i>Clarias gariepinus</i> (African Catfish) in fish ponds in Anambra North Senatorial zones in Anambra State, Nigeria, and to determine the seasonal bacterial load of the organs and antibiotic susceptibility profile of the isolates to conventional antibiotics. A total of 720 African catfish were sampled from randomly selected fish farms during rainy and dry seasons. Bacteria isolates inoculated on Blood and Nutrient agar plates were identified based on morphological and biochemical characteristics. Susceptibility of the isolates to antibiotics was carried out using the Kirby-Bauer disc diffusion method. Isolates from the fish organs include species of <i>Vibrio, Aeromonas, Pseudomonas, Lactobacillus, Staphylococcus, Microbacterium, Serratia, Proteus, Bacillus, Streptococcus, Citrobacter</i> and <i>Micrococcus</i>. Results also revealed that there was significant difference (p value < 0.05) in the bacterial load recovered from the fish organs, during rainy and dry seasons. <i>Bacillus</i> sp. was the most abundant gram positive bacterium in the organs of the fish samples during the rainy and dry season, while <i>Citrobacter</i> sp., a gram negative organism, was relatively abundant in the liver and gut. Percentage susceptibility of the bacteria to antibiotics was highest with vancomycin (100%) and least with erythromycin (75.0%). The most susceptible isolates were species of <i>Staphylococcus, Microccoccus</i> and <i>Microbacterium</i> while <i>Bacillus</i> sp. was the most resistant bacterium. This study has shown that high bacteria load are found in the internal organs of the fish and a good number of the bacteria are resistant to some of the antibiotics tested. There is, therefore, need for adherence to proper sanitary measures to avoid bacterial contamination of fish.展开更多
Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio w...Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio were selected to study the effects of different functional fish organizations on the fractal characteristics of fecal micro-structure by scanning electron microscopes(SEM),particles(pores)and cracks analysis system(PCAS).The results showed that fish feces pores mainly consisted of medium pores(cumulative pore number,97%)classified by the International Union of Pure and Applied Chemistry(IUPAC).The grain area fractal dimension D_(1) and the pore-number and pore-size fractal dimension D_(2) were 1.94-1.96 and 2.07-2.19,respectively.The distribution of fish feces pores was very close to the Sierpinski carpet structure,which is the basic fractal construction methods widely used to describe the fractal of pore surface distribution.D_(1)(1.96)and D_(2)(2.19)of Hypophthalmichthys molitrix were the maximum values of the three functional organizations.Combining with the habit of fish,it is inferred that the feces of H.molitrix,the finer the feed and the faster the swimming of fish,the higher the content of feces clay,the larger the fractal dimension of feces,the easier it is to decompose feces,and the high the content of nutrients and organic matter to release into the water.It is demined that fish functional organizations affected the fractal characteristics and the stability of fish feces in water.This study is helpful for further research on water quality prediction and the impact of functional fish organizations on the structure and function of the ecosystem.展开更多
文摘The paper aimed to investigate the concentration variations and evaluate the bioaccumulation as well as the health risk of Cr, Ni, Cu, Zn, As, Cd and Pb in the aquaculture pond ecosystem during a complete breeding cycle. The samples of water, sediment and aquatic organisms were collected from the pond of gull island in the Pearl River Delta, China. In the breeding cycle, the results revealed the metal concentration in the water increased, while the sediment metal concentration showed no significant difference. The heavy metal concentrations in the water were higher than the background values (December 2017) which related to the input of feeds. Sediment metal concentrations (Cr, Ni, Cu, Zn, As and Cd) in the sediment were higher than the background values of Guangdong Province, China, indicating these metal pollutions came from anthropogenic activities. While the concentration of Pb was comparable to the background value, implying that the Pb was mainly from the earth crust. In addition, various metals showed different affinity to fish organs (muscle, skin, bladder, gill, heart, kidney and liver). Zinc was abundant in skin, while As and Cd concentrations were highest in kidneys;Cu was accumulated highest in liver;Cr concentrations was highest in hearts;and Ni was mainly found in bladders, and the Pb was most commonly found in gills. The distribution of heavy metals in the tissues organs was in the sequence of: Zn > Cu > Cr > Ni > Pb > As > Cd. As the fish ages, the Cu and Zn concentration in tissue organs declined, while the Cr, Ni, As, Cd and Pb increased slightly. Estimations of health risks showed no evidence of potential threats to consumers.
文摘Fishes are cheap sources of protein and are commonly reared in artificial pond in Nigeria. Bacterial infested fishes have been a serious public health concern. This study was aimed at isolating and identifying bacteria associated with the internal organs (gills, liver, guts) of <i>Clarias gariepinus</i> (African Catfish) in fish ponds in Anambra North Senatorial zones in Anambra State, Nigeria, and to determine the seasonal bacterial load of the organs and antibiotic susceptibility profile of the isolates to conventional antibiotics. A total of 720 African catfish were sampled from randomly selected fish farms during rainy and dry seasons. Bacteria isolates inoculated on Blood and Nutrient agar plates were identified based on morphological and biochemical characteristics. Susceptibility of the isolates to antibiotics was carried out using the Kirby-Bauer disc diffusion method. Isolates from the fish organs include species of <i>Vibrio, Aeromonas, Pseudomonas, Lactobacillus, Staphylococcus, Microbacterium, Serratia, Proteus, Bacillus, Streptococcus, Citrobacter</i> and <i>Micrococcus</i>. Results also revealed that there was significant difference (p value < 0.05) in the bacterial load recovered from the fish organs, during rainy and dry seasons. <i>Bacillus</i> sp. was the most abundant gram positive bacterium in the organs of the fish samples during the rainy and dry season, while <i>Citrobacter</i> sp., a gram negative organism, was relatively abundant in the liver and gut. Percentage susceptibility of the bacteria to antibiotics was highest with vancomycin (100%) and least with erythromycin (75.0%). The most susceptible isolates were species of <i>Staphylococcus, Microccoccus</i> and <i>Microbacterium</i> while <i>Bacillus</i> sp. was the most resistant bacterium. This study has shown that high bacteria load are found in the internal organs of the fish and a good number of the bacteria are resistant to some of the antibiotics tested. There is, therefore, need for adherence to proper sanitary measures to avoid bacterial contamination of fish.
基金financial support from the National Natural Science Youth Foundation of China(No.32002443)the Natural Science Foundation of Shandong Province(No.ZR2021QD 149)。
文摘Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio were selected to study the effects of different functional fish organizations on the fractal characteristics of fecal micro-structure by scanning electron microscopes(SEM),particles(pores)and cracks analysis system(PCAS).The results showed that fish feces pores mainly consisted of medium pores(cumulative pore number,97%)classified by the International Union of Pure and Applied Chemistry(IUPAC).The grain area fractal dimension D_(1) and the pore-number and pore-size fractal dimension D_(2) were 1.94-1.96 and 2.07-2.19,respectively.The distribution of fish feces pores was very close to the Sierpinski carpet structure,which is the basic fractal construction methods widely used to describe the fractal of pore surface distribution.D_(1)(1.96)and D_(2)(2.19)of Hypophthalmichthys molitrix were the maximum values of the three functional organizations.Combining with the habit of fish,it is inferred that the feces of H.molitrix,the finer the feed and the faster the swimming of fish,the higher the content of feces clay,the larger the fractal dimension of feces,the easier it is to decompose feces,and the high the content of nutrients and organic matter to release into the water.It is demined that fish functional organizations affected the fractal characteristics and the stability of fish feces in water.This study is helpful for further research on water quality prediction and the impact of functional fish organizations on the structure and function of the ecosystem.
