The effects of natural fish oil, DHA oil and soybean lecithin in microparticulate diets on stress tolerance of larval gilthead seabream ( Sparus aurata ) were investigated after 15 days feeding trials. The tolerance o...The effects of natural fish oil, DHA oil and soybean lecithin in microparticulate diets on stress tolerance of larval gilthead seabream ( Sparus aurata ) were investigated after 15 days feeding trials. The tolerance of larval gilthead seabream to various stress factors such as exposure to air ( lack of dissolved oxygen), changes in water temperature (low) and salinity ( high) were determined. This study showed that microparticulate diet with natural fish oil and soybean lecithin was the most effective for increasing the tolerance of larval gilthead seabream to various stresses, and that microparticulate diet with natural fish oil and palmitic acid (16:0) was more effective than microparticulate diet with DHA oil and soybean lecithin.展开更多
This study examined the effects of dietary α-tocopheryl acetate supplementation on antioxidant enzyme activities and fillet quality in commercial-size Sparus macrocephalus. Three hundred fish [main initial weight （3...This study examined the effects of dietary α-tocopheryl acetate supplementation on antioxidant enzyme activities and fillet quality in commercial-size Sparus macrocephalus. Three hundred fish [main initial weight （350±12） g] were divided into three groups （E250, E500 and El000） and reared in 9 cages. The fish were fed for 8 weeks with three diets containing different levels of dietary α-tocopheryl acetate （289, 553, 1069 mg/kg）. Over the experimental period, fish were fed to satiation and reached a final mean weight of （465±28） g without significant body weight difference and proximate composition difference. Fillet α-tocopherol was significantly （P〈0.05） different between groups, reaching levels of 14.2, 22.1, 30.9 pg/mg fillet for groups E250, E500 and El000, respectively. Total serum superoxide dismutase （SOD） activity increased significantly （P〈0.05） in fish fed the diets high in α-tocopheryl acetate, but serum glutathione peroxidase （GPX） activity was unaffected. In storage on ice, fillets of fish fed the diets high in α-tocopheryl acetate exhibited significantly lower （P〈0.05） levels of oxidation. These results suggested that increased dietary α-tocopheryl acetate could increase its flesh deposition, increase the activity of SOD and prevent lipid peroxidation ofSparus macrocephalus fillets in retail storage on ice.展开更多
Growth of black porgy. Sparus macrocephalus was studied experimentally at four ration lerels from starvation to sltiation and tour temperatures ranging from 14.8 to 26.8℃ .At maximum rations. the specific growth rate...Growth of black porgy. Sparus macrocephalus was studied experimentally at four ration lerels from starvation to sltiation and tour temperatures ranging from 14.8 to 26.8℃ .At maximum rations. the specific growth rate (SGR) increased with temperature and was a negative linear function of body weight. The relationship betaren SGR and ration levels was a decelerating curve. Stepwise mpgression was used to derelop the predictive models for the specific growth rates. Maintenance rations and optimum ratlons both increased with increased temperature. The relationship between maintenance. optimum rations and body welght wds influenced by temperuture. Conversion efficiencies increased with ration from zero at maintenance ration to a peak at the optimum ration, then declined with further inceased ration.展开更多
The study was conducted to investigate fasting effects on flesh composition and antioxidant defenses of market-size Sparus macrocephalus. Two hundred fish (main initial weight 580 g) were divided into two groups (cont...The study was conducted to investigate fasting effects on flesh composition and antioxidant defenses of market-size Sparus macrocephalus. Two hundred fish (main initial weight 580 g) were divided into two groups (control and fasted) and reared in 6 cages. After two weeks of adaptation, group I fasted for 28 d; group II was fed normally as a control. In 3, 7, 14, 21 and 28 d, 6 fish per group were sampled for proximate flesh composition, liver antioxidant enzyme activities and malondialdehyde flesh content analyses. In fasted fish, the reduction of lipid content in muscle occurred after day 3, and, compared to controls, the content of protein decreased from day 14, the activities of liver antioxidative enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) increased from day 3, and flesh malondialdehyde levels increased from day 21. Flesh fat reduction shows that fasting may be used as a technique to reduce flesh lipid content in Sparus macrocephalus. However, considering flesh protein loss and the subsequent oxidative stress, the fasting technique should be used with precautions.展开更多
Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream (Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five ...Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream (Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five treatments with rotifers and Artemia differing in n-3 HUFA were prepared by enriching them with various oil emulsions. Results indicated that dietary n-3 HUFA significantly influence fish n-3 HUFA levels and are essential for growth and survival of black sea bream larvae. The results also indicated that the incorporation of n-3HUFA TG (triacylglycerols) into tissues of larval black sea bream was more effective from natural fish oil in comparison with n-3 HUFA fatty acid ethyl esters from ethyl-esterified oil.展开更多
The residual concentrations of HCHs, TC, DDTs, THCs and PCBs were measured in Sparus auratus collected from the eastern and western sectors of the Egyptian Mediterranean Sea, as the most common fish species in the are...The residual concentrations of HCHs, TC, DDTs, THCs and PCBs were measured in Sparus auratus collected from the eastern and western sectors of the Egyptian Mediterranean Sea, as the most common fish species in the area. Gas chromatograph equipped with 63Ni-electron capture detector and 35% phenyl polysilphenylenesiloxane capillary column was used for the analysis and quantification after well-established extraction techniques. The concentrations (wet weight) of PCBs, DDTs, TCs, HCHs were: (1.87 - 616.66 ng·g-1), (0.42 - 98.28 ng·g-1), (0.06 - 2.94 ng·g-1), (0.35 - 11.77 ng·g-1), respectively in Sparus auratus collected from the eastern sector. However, these concentrations as wet weight in Sparus auratus from the western sector were: (5.75 - 605.53 ng·g-1), (1.53 - 226.47 ng·g-1), (0.09 - 8.12 ng·g-1), (0.26 - 5.80 ng·g-1), respectively. In general, concentrations of pesticides and PCBs in Sparus auratus either from the western or eastern Egyptian Mediterranean coast were far below the international permissible levels.展开更多
Vibrionaceae are a common bacterial disease that affects both wild and farmed marine fishes and causes tremendous economic losses globally.In order to investigate the prevalence,molecular typing,antibiogram and pathog...Vibrionaceae are a common bacterial disease that affects both wild and farmed marine fishes and causes tremendous economic losses globally.In order to investigate the prevalence,molecular typing,antibiogram and pathogenicity of vibriosis among cultured sea bream,two hundred and fifty Gilthead seabream(Sparus aurata)were collected randomly from different mariculture farms at Ismailia and Port Said Governorates.The collected fish were subjected to clinical,postmortem,bacteriological,and histopathological examinations.The majority of infected fish displayed ascites,hemorrhagic protruded anus,hemorrhages in pectoral,dorsal and tail fins,rotten gills,thinning of the head,discoloration of the skin,besides ulcer in the mouth and on the skin.The prevalence of Vibrio infection mostly was noticed at summer(35%)and spring(26%)then(22.5%)in autumn,where the kidney was the most predominant affected organ(45%).Vibrio 16s rRNA gene PCR extension generated a 663 pb amplified DNA bands that characteristic for all tested vibrio isolates.Blasting identified as V.harveyi and the other V.parahaemolyticus.The histopathological examination of naturally infected Gilthead seabream exhibited mild to moderate vacuolar degeneration of the hepatic parenchyma with tubular-nephrosis and massive renal cellular destruction.The splenic tissues showed focal activated melanomacrophage centers.The antimicrobial sensitivity was carried out,where the recovered strains were completely sensitive to novobiocin and highly resistant to ampicillin.In conclusion,the synergism of phenotypic and genotypic characterization is a valuable epidemiological tool for the diagnosis of Vibrio species.Strict veterinary hygienic regulations should be imple-mented to control such infections and minimize the antimicrobial use in fish farms.展开更多
Spawning performance-relative fecundity and fertilization success-was studied in two hatchery-reared broodstocks of gilthead seabream(Sparus aurata)held under relatively constant well-water temperature(18-20◦C)and sim...Spawning performance-relative fecundity and fertilization success-was studied in two hatchery-reared broodstocks of gilthead seabream(Sparus aurata)held under relatively constant well-water temperature(18-20◦C)and simulated natural photoperiod,for five consecutive spawning seasons,between 3 and 7 years of age.The spawning season lasted between 4 and 6 months each year,and the total number of eggs produced annually ranged between 1480000 and 3100000 eggs/kg female body weight,being the highest during the first and second spawning season.No difference was observed in monthly relative fecundity between years-although high variation existed within years,whereas fertilization success was the highest during the second and third reproductive season,and dropped significantly during the last year of the study.The male percentage of the broodstocks was 35%during the first spawning season of the females,and thereafter it decreased further and remained stable at around 15%-20%for the second and third spawning season.Substitution of older females with smaller males to readjust male percentage to 50%in the fourth spawning season,was followed by sex change of larger males to females and a drop of the male percentage to 18%in the following spawning season.The present study demonstrated the long spawning season of gilthead seabream-especially under constant water temperature,the high fecundity and fertilization success,and the stabilization of male percentage to~20%after the first spawning season or when a broodstock is modified to increase male percentage.These results are useful to the aquaculture industry,demonstrating that there is no need to add males to gilthead seabream broodstocks over the years,as the sex ratio is stabilized and egg production and fertilization success remain high with a relatively low male:female sex ratio.展开更多
The sea area surrounding Baishishan Island has abundant fishery resources because of its plentiful food and rocky reefs that provide refuge from predators.However,overfishing has occurred in many areas and some specie...The sea area surrounding Baishishan Island has abundant fishery resources because of its plentiful food and rocky reefs that provide refuge from predators.However,overfishing has occurred in many areas and some species’local populations need to be replenished through stocking programs.This case study,using Sparus microcephalus as the test species,designed and analyzed detailed stocking strategies to improve the survival ratio and control the active range of the released fishes.Controlled variables included release location,release time,and tidal level.Two stocking strategies were designed,executed,and evaluated for comparison.A traditional stocking method was applied to the high flow area of Baishishan Island in Xiangshan Bay,East China Sea.The released fry were transported by boat and released to the sea using buckets.Released fish were traced using plastic tags.The average distance of the 19 recaptured fry from the release point was 7.6 km with 52.9%mortality rate.The distance at recapture and mortality rate among recaptured individuals showed that the traditional releasing method was not successful.An in situ stocking method was used in a low tide area and natural process was imitated to decrease the stress response and promote physiological adaptation.The purpose of this method was to prolong the release process applying temporary net cages at the release location,which resulted in a regional distribution of the released fish and possibly improving the food availability.A new Sr+tagging technique was adopted to evaluate the release effect and quantify comparative release data.Only 1 fish among the 354 caught was found farther than 1 km from the release point in the following 6 months.The results validated the promotion of the new stocking technique.展开更多
文摘The effects of natural fish oil, DHA oil and soybean lecithin in microparticulate diets on stress tolerance of larval gilthead seabream ( Sparus aurata ) were investigated after 15 days feeding trials. The tolerance of larval gilthead seabream to various stress factors such as exposure to air ( lack of dissolved oxygen), changes in water temperature (low) and salinity ( high) were determined. This study showed that microparticulate diet with natural fish oil and soybean lecithin was the most effective for increasing the tolerance of larval gilthead seabream to various stresses, and that microparticulate diet with natural fish oil and palmitic acid (16:0) was more effective than microparticulate diet with DHA oil and soybean lecithin.
基金Project (No. 2006c12098) supported by the Science and TechnologyDepartment of Zhejiang Province, China
文摘This study examined the effects of dietary α-tocopheryl acetate supplementation on antioxidant enzyme activities and fillet quality in commercial-size Sparus macrocephalus. Three hundred fish [main initial weight （350±12） g] were divided into three groups （E250, E500 and El000） and reared in 9 cages. The fish were fed for 8 weeks with three diets containing different levels of dietary α-tocopheryl acetate （289, 553, 1069 mg/kg）. Over the experimental period, fish were fed to satiation and reached a final mean weight of （465±28） g without significant body weight difference and proximate composition difference. Fillet α-tocopherol was significantly （P〈0.05） different between groups, reaching levels of 14.2, 22.1, 30.9 pg/mg fillet for groups E250, E500 and El000, respectively. Total serum superoxide dismutase （SOD） activity increased significantly （P〈0.05） in fish fed the diets high in α-tocopheryl acetate, but serum glutathione peroxidase （GPX） activity was unaffected. In storage on ice, fillets of fish fed the diets high in α-tocopheryl acetate exhibited significantly lower （P〈0.05） levels of oxidation. These results suggested that increased dietary α-tocopheryl acetate could increase its flesh deposition, increase the activity of SOD and prevent lipid peroxidation ofSparus macrocephalus fillets in retail storage on ice.
文摘Growth of black porgy. Sparus macrocephalus was studied experimentally at four ration lerels from starvation to sltiation and tour temperatures ranging from 14.8 to 26.8℃ .At maximum rations. the specific growth rate (SGR) increased with temperature and was a negative linear function of body weight. The relationship betaren SGR and ration levels was a decelerating curve. Stepwise mpgression was used to derelop the predictive models for the specific growth rates. Maintenance rations and optimum ratlons both increased with increased temperature. The relationship between maintenance. optimum rations and body welght wds influenced by temperuture. Conversion efficiencies increased with ration from zero at maintenance ration to a peak at the optimum ration, then declined with further inceased ration.
基金Project (No. 2006C12098) supported by the Science and Technology Department of Zhejiang Province, China
文摘The study was conducted to investigate fasting effects on flesh composition and antioxidant defenses of market-size Sparus macrocephalus. Two hundred fish (main initial weight 580 g) were divided into two groups (control and fasted) and reared in 6 cages. After two weeks of adaptation, group I fasted for 28 d; group II was fed normally as a control. In 3, 7, 14, 21 and 28 d, 6 fish per group were sampled for proximate flesh composition, liver antioxidant enzyme activities and malondialdehyde flesh content analyses. In fasted fish, the reduction of lipid content in muscle occurred after day 3, and, compared to controls, the content of protein decreased from day 14, the activities of liver antioxidative enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) increased from day 3, and flesh malondialdehyde levels increased from day 21. Flesh fat reduction shows that fasting may be used as a technique to reduce flesh lipid content in Sparus macrocephalus. However, considering flesh protein loss and the subsequent oxidative stress, the fasting technique should be used with precautions.
文摘Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream (Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five treatments with rotifers and Artemia differing in n-3 HUFA were prepared by enriching them with various oil emulsions. Results indicated that dietary n-3 HUFA significantly influence fish n-3 HUFA levels and are essential for growth and survival of black sea bream larvae. The results also indicated that the incorporation of n-3HUFA TG (triacylglycerols) into tissues of larval black sea bream was more effective from natural fish oil in comparison with n-3 HUFA fatty acid ethyl esters from ethyl-esterified oil.
文摘The residual concentrations of HCHs, TC, DDTs, THCs and PCBs were measured in Sparus auratus collected from the eastern and western sectors of the Egyptian Mediterranean Sea, as the most common fish species in the area. Gas chromatograph equipped with 63Ni-electron capture detector and 35% phenyl polysilphenylenesiloxane capillary column was used for the analysis and quantification after well-established extraction techniques. The concentrations (wet weight) of PCBs, DDTs, TCs, HCHs were: (1.87 - 616.66 ng·g-1), (0.42 - 98.28 ng·g-1), (0.06 - 2.94 ng·g-1), (0.35 - 11.77 ng·g-1), respectively in Sparus auratus collected from the eastern sector. However, these concentrations as wet weight in Sparus auratus from the western sector were: (5.75 - 605.53 ng·g-1), (1.53 - 226.47 ng·g-1), (0.09 - 8.12 ng·g-1), (0.26 - 5.80 ng·g-1), respectively. In general, concentrations of pesticides and PCBs in Sparus auratus either from the western or eastern Egyptian Mediterranean coast were far below the international permissible levels.
文摘Vibrionaceae are a common bacterial disease that affects both wild and farmed marine fishes and causes tremendous economic losses globally.In order to investigate the prevalence,molecular typing,antibiogram and pathogenicity of vibriosis among cultured sea bream,two hundred and fifty Gilthead seabream(Sparus aurata)were collected randomly from different mariculture farms at Ismailia and Port Said Governorates.The collected fish were subjected to clinical,postmortem,bacteriological,and histopathological examinations.The majority of infected fish displayed ascites,hemorrhagic protruded anus,hemorrhages in pectoral,dorsal and tail fins,rotten gills,thinning of the head,discoloration of the skin,besides ulcer in the mouth and on the skin.The prevalence of Vibrio infection mostly was noticed at summer(35%)and spring(26%)then(22.5%)in autumn,where the kidney was the most predominant affected organ(45%).Vibrio 16s rRNA gene PCR extension generated a 663 pb amplified DNA bands that characteristic for all tested vibrio isolates.Blasting identified as V.harveyi and the other V.parahaemolyticus.The histopathological examination of naturally infected Gilthead seabream exhibited mild to moderate vacuolar degeneration of the hepatic parenchyma with tubular-nephrosis and massive renal cellular destruction.The splenic tissues showed focal activated melanomacrophage centers.The antimicrobial sensitivity was carried out,where the recovered strains were completely sensitive to novobiocin and highly resistant to ampicillin.In conclusion,the synergism of phenotypic and genotypic characterization is a valuable epidemiological tool for the diagnosis of Vibrio species.Strict veterinary hygienic regulations should be imple-mented to control such infections and minimize the antimicrobial use in fish farms.
基金supported by an internal program (GnRHa implants,60.70101)from the Institute of Marine Biology,Biotechnology and Aquaculture of the Hellenic Center for Marine Research to CCM.
文摘Spawning performance-relative fecundity and fertilization success-was studied in two hatchery-reared broodstocks of gilthead seabream(Sparus aurata)held under relatively constant well-water temperature(18-20◦C)and simulated natural photoperiod,for five consecutive spawning seasons,between 3 and 7 years of age.The spawning season lasted between 4 and 6 months each year,and the total number of eggs produced annually ranged between 1480000 and 3100000 eggs/kg female body weight,being the highest during the first and second spawning season.No difference was observed in monthly relative fecundity between years-although high variation existed within years,whereas fertilization success was the highest during the second and third reproductive season,and dropped significantly during the last year of the study.The male percentage of the broodstocks was 35%during the first spawning season of the females,and thereafter it decreased further and remained stable at around 15%-20%for the second and third spawning season.Substitution of older females with smaller males to readjust male percentage to 50%in the fourth spawning season,was followed by sex change of larger males to females and a drop of the male percentage to 18%in the following spawning season.The present study demonstrated the long spawning season of gilthead seabream-especially under constant water temperature,the high fecundity and fertilization success,and the stabilization of male percentage to~20%after the first spawning season or when a broodstock is modified to increase male percentage.These results are useful to the aquaculture industry,demonstrating that there is no need to add males to gilthead seabream broodstocks over the years,as the sex ratio is stabilized and egg production and fertilization success remain high with a relatively low male:female sex ratio.
基金The study was financially supported by the National Natural Science Foundation of China(No.51309150)Special Fund for Agro-scientific Research in the Public Interest(No.201303047).
文摘The sea area surrounding Baishishan Island has abundant fishery resources because of its plentiful food and rocky reefs that provide refuge from predators.However,overfishing has occurred in many areas and some species’local populations need to be replenished through stocking programs.This case study,using Sparus microcephalus as the test species,designed and analyzed detailed stocking strategies to improve the survival ratio and control the active range of the released fishes.Controlled variables included release location,release time,and tidal level.Two stocking strategies were designed,executed,and evaluated for comparison.A traditional stocking method was applied to the high flow area of Baishishan Island in Xiangshan Bay,East China Sea.The released fry were transported by boat and released to the sea using buckets.Released fish were traced using plastic tags.The average distance of the 19 recaptured fry from the release point was 7.6 km with 52.9%mortality rate.The distance at recapture and mortality rate among recaptured individuals showed that the traditional releasing method was not successful.An in situ stocking method was used in a low tide area and natural process was imitated to decrease the stress response and promote physiological adaptation.The purpose of this method was to prolong the release process applying temporary net cages at the release location,which resulted in a regional distribution of the released fish and possibly improving the food availability.A new Sr+tagging technique was adopted to evaluate the release effect and quantify comparative release data.Only 1 fish among the 354 caught was found farther than 1 km from the release point in the following 6 months.The results validated the promotion of the new stocking technique.
