The rabbitfish Siganus canaliculatus is one of the few cultured herbivorous marine teleosts. To better understand the digestive physiology of this fish and provide data for designing formulated feed using macroalgae a...The rabbitfish Siganus canaliculatus is one of the few cultured herbivorous marine teleosts. To better understand the digestive physiology of this fish and provide data for designing formulated feed using macroalgae as an ingredient, the changes of visceral properties and digestive enzyme activities were investigated after the juveniles were fed on different types of food including raw fish（RF）, formulated diet（FD） or macroalgae Enteromorpha prolifra（EP） and Gracilaria lemaneiformis（GL） for eight weeks. The results showed that the hepatosomatic and viscerosomatic indices in the RF and FD groups, as well as the relative intestine length（RIL） in the EP and GL groups, were significantly higher than those in other groups. Additionally, differences in the histological structure of the liver and anterior intestine were also observed among different dietary groups. The hepatic nuclei were displaced to the periphery by lipid inclusions in fish fed RF. The highest levels of mucosal folds were found in the anterior intestines of fish fed macroalgae. Digestive enzyme activity profiles showed obvious fluctuations in the first three weeks, and then leveled off in the following weeks. The levels of protease, lipase and α-amylase in the alimentary tract showed changes related to the levels of dietary protein, lipid and carbohydrate, respectively.Although macroalgae significantly inhibited the activity of protease in the stomach, it increased RIL and the number of mucosal folds in the anterior intestine so as to compensate for the influences on protease activities in the stomach. This study suggests that the digestive tract of rabbitfish can well adapt to different diets, and needs about three weeks to physiologically acclimatize to the nutritional status, thus implying that rabbitfish are somewhat omnivorous.展开更多
In order to provide reference for using Sigartus guttatus to control overgrowth of Ertteromorpha prolifra, the growth, serum biochemical and antioxidant enzyme indices of juvenile S. guttatus respectively fed with E. ...In order to provide reference for using Sigartus guttatus to control overgrowth of Ertteromorpha prolifra, the growth, serum biochemical and antioxidant enzyme indices of juvenile S. guttatus respectively fed with E. prolifra and artificial feed were studied. One hundred and eighty individuals were cultivated for 90 days in six 2.5 m × 1.5 m × 1.5 m cages （30 ind. per cage） which mesh size were 0.5 mm. The experimental animals were divided into two dietary groups （ three cages for each group） that were fed with E. prolifra and artificial feed respectively. During the culture period, temperatures ranged from 23.0 to 26.5℃, pH was between 7.8 and 8.2, dissolved oxygen was more than 5.0 mg/L. The weight gain rate, specific growth rate, relative growth rate, hepato-somatic index of juvenile S. guttatus fed with E. prolifra were significantly lowe than that fed with artificial feed （P 〈 0.05）. The total protein （TP）, urea nitrogen （UN） and alkaline phosphatase （AKP） of juvenile S. guttatus fed with E. Prolifra were significantly higher than that fed with artificial feed （P 〈0.05）, while glutamic oxalacetie transaminase （AST/GOT） and glutamic-pyruvic transaminase （ALT/GPT） of juvenile S. guttatus fed with E. prolifra were significantly lower than that fed with artificial feed （P 〈 0.05 ）. SOD, GPX and anti-superoxide anion radical activity in liver, kidney, gill and muscle of juvenile S. guttatus fed with E. prolifra were higher than that fed with artificial feed, and these antioxidant enzyme activities in kidney of juvenile S. gtatatus fed with E. prolifra was significantly higher than that fed with artificial feed （P 〈 0.05）, while CAT and hydroxyl radical-inhibiting activity in liver of juvenile S. guttatus fed with arti- ficial feed were significantly higher than that fed with E. prolifra （P 〈 0.05 ）. Juvenile S. guttatus fed with E. prolifra showed poor growth performance but better antioxidant defense system. S. guttatus is easily raised and has strong展开更多
Fishes represent the highest diversity of vertebrates; however, our understanding of the compositions and functions of their gut microbiota is limited. In this study, we provided the first insight into the gut microbi...Fishes represent the highest diversity of vertebrates; however, our understanding of the compositions and functions of their gut microbiota is limited. In this study, we provided the first insight into the gut microbiota of the herbivorous fish Siganus eanalieulatus by using three molecular ecology techniques based on the 16S rRNA genes （denaturing gradient gel electrophoresis, clone library construction, and high- throughput Illumina sequencing）, and the Illumina sequencing technique is suggested here due to its higher overall coverage of the total 16S rRNA genes. A core gut microbiota of 29 bacterial groups, covering 〉99.9% of the total bacterial community, was found to be dominated by Proteobacteria and Firmicutes in fish fed three different diets with/without the supplementation of Ulva pertusa and non-starch polysaccharide （NSP） enzymes （cellulase, xylanase, and [3-glucanase）. Diverse potential NSP-degrading bacteria and probiotics （e.g., Ruminococcus, Clostridium and Lachnospiraceae） were detected in the intestine of the fish fed U. pertusa, suggesting that these microorganisms likely participated in the degradation of NSPs derived from U. pertusa. This study supports our previous conclusion that U. pertusa-based diets are suitable for the production ofS. eanaliculatus with lower costs without compromising quality.展开更多
[ Objective] This experiment was conducted to analyze and compare the nutritional components in the muscle of juvenile Siganus guttatus fed with Enteromorpha prolifera and artificial feed. [ Method] A total of 180 hea...[ Objective] This experiment was conducted to analyze and compare the nutritional components in the muscle of juvenile Siganus guttatus fed with Enteromorpha prolifera and artificial feed. [ Method] A total of 180 healthy S. guttatus juveniles with similar body size were assigned into two groups： one fed with E. prolifera, and the other fed with artificial feed, respectively. There were three replicates in each group, and 30 fish in each replicate. And the experiment lasted for 90 d. [ Result] The results showed that the weight gain rate, specific growth rate and relative growth rate of E. prolifera-fed group were significantly lower than those of artificial feed-fed group （P 〈0.05） ; the contents of crude protein and crude ash of E. prolifera-fed group were significantly higher than those of artificial feed-fed group （P 〈 0.05 ）. However, the content of crude fat of E. prolifera-fed group was significantly lower than that of artificial feed-fed group （P 〈 0.05 ）. The moisture content had no significant difference between the two groups （P 〉 0.05 ）. The amino acid composition was similar between the two groups. Seventeen amino acids were found in both groups, and the essential amino acid index （EAAI） was 76.71 in E. prolifera-fed group and 70.05 in artificial feed-fed group, both of which met the criteria set by the Food and Agriculture Organization of the United Nations （FAO）/World Health Organization （WHO）. The content of eicosapentaenoic acid （EPA） ＋ docosahexaenoic acid （DHA） and the content of to-3 polyunsaturated fatty acids （ to-3 PUFAs） of E. prolifera-fed group were significantly higher than those of artificial feed-fed group （ P 〈 0.05 ）. [ Conclusion ] In conclusion, the juvenile S. guttatus in both groups contains a variety of nutritional components. S. guttatus fed with E. prolifera has higher levels of essential amino acids, more balanced composition of polyunsaturated fatty acids, higher nutritive val- ue and better taste than that fed with 展开更多
The decomposition of a large amount of unexploited macroalgal resource along the coast of China often results in heavy environmental pollution. In order to pave a way of using macroalgae as the dietary ingredient of r...The decomposition of a large amount of unexploited macroalgal resource along the coast of China often results in heavy environmental pollution. In order to pave a way of using macroalgae as the dietary ingredient of rabbitfish Siganus canaliculatus, one of a few farmed herbivorous marine teleosts in China, its preference(feeding selectivity) for different macroalgae was determined in this study. Seven seaweed species abundantly inhabiting the coast of east Guangdong Province were exposed simultaneously to rabbitfish juveniles in laboratory(multiple-choice feeding) with their content and absolute intake assayed. It was found that the most preferred algae were Ulva prolifera, Gracilaria lemaneiformis and Chaetomorpha linum, less preferred algae were U. pertusa and Porphyra haitanensis, and least preferred ones were Sargassum fusiforme and Corallina sessilis. Such an order did not change when one to four relatively preferred seaweeds were removed. The preferred seaweeds were richer in protein and soluble sugar thus higher in energy than the least preferred. In addition, this fish was found to favor filamentous and flat algae rather than calcified ones. Accordingly, the richness of nutrients and morphological characteristics determined the preference of S. canaliculatus for tested macroalgae.展开更多
This study was conducted to study the effects of a commercial exogenous digestive enzymes （EDE） containing cellulases, xylanases, u-amylase and proteases from anaerobic bacterium and natural enhancer mixture （NEM）...This study was conducted to study the effects of a commercial exogenous digestive enzymes （EDE） containing cellulases, xylanases, u-amylase and proteases from anaerobic bacterium and natural enhancer mixture （NEM） containing allicin, high unit hydrolytic enzyme, Bacillus subtilis spores and ginseng extracts on survival, growth, carcass composition and feed cost/benefit in rabbitfish, Siganus rivulatus. Nine net cages （100 cm × 100 cm × 40 cm; L ×W ×H） were stocked with 10 juvenile rabbitfish （1.1 g per fish） each and placed in a large rectangular tank and offered feed at 4% body weight daily. Three replicates per treatment were offered three isonitrogenous and isocaloric diets, control and two supplemented diets with EDE or NEM at 2 g/kg diet for 74 days. Fish in all cages were weighed at two-week intervals and feed regimen was adjusted accordingly. Rabbitfish offered the control diet exhibited lower growth significantly （P 〈 0.05） and feed utilization than the other two experimental treatments. Experimental diet supplemented with NEM recorded the highest growth performance, feed conversion ratio, protein efficiency ratio, net protein utilization and energy retention significantly （P 〈 0.05） than the other two tested groups. Carcass composition and somatic parameters index was not affected by dietary EDE or NEM inclusion. Ultimately, when all variables are considered, EDE and NEM inclusion to diets appears to reduce feed cost per unit growth of rabbitfish.展开更多
Marine ecosystems provide a wide variety of diverse habitats that frequently promote migration and ecological adaptation.The extent to which the geographic distribution of marine organism has reshaped by human activit...Marine ecosystems provide a wide variety of diverse habitats that frequently promote migration and ecological adaptation.The extent to which the geographic distribution of marine organism has reshaped by human activities remains underappreciated.The limitations intrinsic to morphology-based identification systems have engendered an urgent need for reliable genetic methods that enable the unequivocal recognition of fish species,particularly those that are prone to overexploitation and/or market substitution.In the present study,however,an attempt has been taken to identify two locally adapted fish species,Siganus sutor(Valenciennes,1835)and Seriolina nigrofasciata(Rüppell,1829)of order Perciformes,which happens to be the first record in Odisha coast,Bay of Bengal.The diagnostic characteristics of Siganus sutor are:dorsal fin XIII-10,anal fin VII-9,pectoral fin 15,pelvic fin II-3,while that of Seriolina nigrofasciata dorsal fin VI-I-35,anal fin I-17,pectoral fin 16,pelvic fin 5.All COI barcodes generated in this study were matched with reference sequences of expected species,according to morphological identification.Bayesian and likelihood phylogenetic trees were drawn based on DNA barcodes and all the specimens clustered in agreement with their taxonomic classification at the species level.The phylogeographic studies based on haplotype network and migration rates suggest that both the species were not panmitic and the high-frequency population distribution indicates successful migration.The result of this study provides an important validation of the use of DNA barcode sequences for monitoring species diversity and changes within a complex marine ecosystem.展开更多
基金The Major International Joint Research Project from the National Natural Science Foundation of China(NSFC)under contract No.31110103913the NSFC Youth Project under contract No.31602176China Agriculture Research System under contract No.CARS-47
文摘The rabbitfish Siganus canaliculatus is one of the few cultured herbivorous marine teleosts. To better understand the digestive physiology of this fish and provide data for designing formulated feed using macroalgae as an ingredient, the changes of visceral properties and digestive enzyme activities were investigated after the juveniles were fed on different types of food including raw fish（RF）, formulated diet（FD） or macroalgae Enteromorpha prolifra（EP） and Gracilaria lemaneiformis（GL） for eight weeks. The results showed that the hepatosomatic and viscerosomatic indices in the RF and FD groups, as well as the relative intestine length（RIL） in the EP and GL groups, were significantly higher than those in other groups. Additionally, differences in the histological structure of the liver and anterior intestine were also observed among different dietary groups. The hepatic nuclei were displaced to the periphery by lipid inclusions in fish fed RF. The highest levels of mucosal folds were found in the anterior intestines of fish fed macroalgae. Digestive enzyme activity profiles showed obvious fluctuations in the first three weeks, and then leveled off in the following weeks. The levels of protease, lipase and α-amylase in the alimentary tract showed changes related to the levels of dietary protein, lipid and carbohydrate, respectively.Although macroalgae significantly inhibited the activity of protease in the stomach, it increased RIL and the number of mucosal folds in the anterior intestine so as to compensate for the influences on protease activities in the stomach. This study suggests that the digestive tract of rabbitfish can well adapt to different diets, and needs about three weeks to physiologically acclimatize to the nutritional status, thus implying that rabbitfish are somewhat omnivorous.
文摘In order to provide reference for using Sigartus guttatus to control overgrowth of Ertteromorpha prolifra, the growth, serum biochemical and antioxidant enzyme indices of juvenile S. guttatus respectively fed with E. prolifra and artificial feed were studied. One hundred and eighty individuals were cultivated for 90 days in six 2.5 m × 1.5 m × 1.5 m cages （30 ind. per cage） which mesh size were 0.5 mm. The experimental animals were divided into two dietary groups （ three cages for each group） that were fed with E. prolifra and artificial feed respectively. During the culture period, temperatures ranged from 23.0 to 26.5℃, pH was between 7.8 and 8.2, dissolved oxygen was more than 5.0 mg/L. The weight gain rate, specific growth rate, relative growth rate, hepato-somatic index of juvenile S. guttatus fed with E. prolifra were significantly lowe than that fed with artificial feed （P 〈 0.05）. The total protein （TP）, urea nitrogen （UN） and alkaline phosphatase （AKP） of juvenile S. guttatus fed with E. Prolifra were significantly higher than that fed with artificial feed （P 〈0.05）, while glutamic oxalacetie transaminase （AST/GOT） and glutamic-pyruvic transaminase （ALT/GPT） of juvenile S. guttatus fed with E. prolifra were significantly lower than that fed with artificial feed （P 〈 0.05 ）. SOD, GPX and anti-superoxide anion radical activity in liver, kidney, gill and muscle of juvenile S. guttatus fed with E. prolifra were higher than that fed with artificial feed, and these antioxidant enzyme activities in kidney of juvenile S. gtatatus fed with E. prolifra was significantly higher than that fed with artificial feed （P 〈 0.05）, while CAT and hydroxyl radical-inhibiting activity in liver of juvenile S. guttatus fed with arti- ficial feed were significantly higher than that fed with E. prolifra （P 〈 0.05 ）. Juvenile S. guttatus fed with E. prolifra showed poor growth performance but better antioxidant defense system. S. guttatus is easily raised and has strong
基金Supported by the National Natural Science Foundation of China(Nos.41641053,41376176,41276179)the Team Project of Natural Science Foundation of Guangdong Province(No.S2011030005257)the China Postdoctoral Science Foundation(No.2016M602501)
文摘Fishes represent the highest diversity of vertebrates; however, our understanding of the compositions and functions of their gut microbiota is limited. In this study, we provided the first insight into the gut microbiota of the herbivorous fish Siganus eanalieulatus by using three molecular ecology techniques based on the 16S rRNA genes （denaturing gradient gel electrophoresis, clone library construction, and high- throughput Illumina sequencing）, and the Illumina sequencing technique is suggested here due to its higher overall coverage of the total 16S rRNA genes. A core gut microbiota of 29 bacterial groups, covering 〉99.9% of the total bacterial community, was found to be dominated by Proteobacteria and Firmicutes in fish fed three different diets with/without the supplementation of Ulva pertusa and non-starch polysaccharide （NSP） enzymes （cellulase, xylanase, and [3-glucanase）. Diverse potential NSP-degrading bacteria and probiotics （e.g., Ruminococcus, Clostridium and Lachnospiraceae） were detected in the intestine of the fish fed U. pertusa, suggesting that these microorganisms likely participated in the degradation of NSPs derived from U. pertusa. This study supports our previous conclusion that U. pertusa-based diets are suitable for the production ofS. eanaliculatus with lower costs without compromising quality.
基金Supported by Special Research Fund for the National Non-profit Institutes(East China Sea Fisheries Research Institute)(NO.2014T15)the Fund for Scientific and Technological Research for Agricultural Development in Shanghai[(2016)No.2-3]
文摘[ Objective] This experiment was conducted to analyze and compare the nutritional components in the muscle of juvenile Siganus guttatus fed with Enteromorpha prolifera and artificial feed. [ Method] A total of 180 healthy S. guttatus juveniles with similar body size were assigned into two groups： one fed with E. prolifera, and the other fed with artificial feed, respectively. There were three replicates in each group, and 30 fish in each replicate. And the experiment lasted for 90 d. [ Result] The results showed that the weight gain rate, specific growth rate and relative growth rate of E. prolifera-fed group were significantly lower than those of artificial feed-fed group （P 〈0.05） ; the contents of crude protein and crude ash of E. prolifera-fed group were significantly higher than those of artificial feed-fed group （P 〈 0.05 ）. However, the content of crude fat of E. prolifera-fed group was significantly lower than that of artificial feed-fed group （P 〈 0.05 ）. The moisture content had no significant difference between the two groups （P 〉 0.05 ）. The amino acid composition was similar between the two groups. Seventeen amino acids were found in both groups, and the essential amino acid index （EAAI） was 76.71 in E. prolifera-fed group and 70.05 in artificial feed-fed group, both of which met the criteria set by the Food and Agriculture Organization of the United Nations （FAO）/World Health Organization （WHO）. The content of eicosapentaenoic acid （EPA） ＋ docosahexaenoic acid （DHA） and the content of to-3 polyunsaturated fatty acids （ to-3 PUFAs） of E. prolifera-fed group were significantly higher than those of artificial feed-fed group （ P 〈 0.05 ）. [ Conclusion ] In conclusion, the juvenile S. guttatus in both groups contains a variety of nutritional components. S. guttatus fed with E. prolifera has higher levels of essential amino acids, more balanced composition of polyunsaturated fatty acids, higher nutritive val- ue and better taste than that fed with
基金financially supported by grants from National Natural Science Foundation of China (No. 41276179)National Science and Technology Support Plan Project (No. 2012BAC07B05)+1 种基金Team Project of Natural Science Foundation of Guangdong Province (S2011030005257)Producing,Teaching and Research Cooperation Projects of Guangdong Province and Ministry of Education (No. 2011B090400039)
文摘The decomposition of a large amount of unexploited macroalgal resource along the coast of China often results in heavy environmental pollution. In order to pave a way of using macroalgae as the dietary ingredient of rabbitfish Siganus canaliculatus, one of a few farmed herbivorous marine teleosts in China, its preference(feeding selectivity) for different macroalgae was determined in this study. Seven seaweed species abundantly inhabiting the coast of east Guangdong Province were exposed simultaneously to rabbitfish juveniles in laboratory(multiple-choice feeding) with their content and absolute intake assayed. It was found that the most preferred algae were Ulva prolifera, Gracilaria lemaneiformis and Chaetomorpha linum, less preferred algae were U. pertusa and Porphyra haitanensis, and least preferred ones were Sargassum fusiforme and Corallina sessilis. Such an order did not change when one to four relatively preferred seaweeds were removed. The preferred seaweeds were richer in protein and soluble sugar thus higher in energy than the least preferred. In addition, this fish was found to favor filamentous and flat algae rather than calcified ones. Accordingly, the richness of nutrients and morphological characteristics determined the preference of S. canaliculatus for tested macroalgae.
文摘This study was conducted to study the effects of a commercial exogenous digestive enzymes （EDE） containing cellulases, xylanases, u-amylase and proteases from anaerobic bacterium and natural enhancer mixture （NEM） containing allicin, high unit hydrolytic enzyme, Bacillus subtilis spores and ginseng extracts on survival, growth, carcass composition and feed cost/benefit in rabbitfish, Siganus rivulatus. Nine net cages （100 cm × 100 cm × 40 cm; L ×W ×H） were stocked with 10 juvenile rabbitfish （1.1 g per fish） each and placed in a large rectangular tank and offered feed at 4% body weight daily. Three replicates per treatment were offered three isonitrogenous and isocaloric diets, control and two supplemented diets with EDE or NEM at 2 g/kg diet for 74 days. Fish in all cages were weighed at two-week intervals and feed regimen was adjusted accordingly. Rabbitfish offered the control diet exhibited lower growth significantly （P 〈 0.05） and feed utilization than the other two experimental treatments. Experimental diet supplemented with NEM recorded the highest growth performance, feed conversion ratio, protein efficiency ratio, net protein utilization and energy retention significantly （P 〈 0.05） than the other two tested groups. Carcass composition and somatic parameters index was not affected by dietary EDE or NEM inclusion. Ultimately, when all variables are considered, EDE and NEM inclusion to diets appears to reduce feed cost per unit growth of rabbitfish.
基金The Aquaculture and Marine Biotechnology Programme Initiative from Department of Biotechnology(DBT),Ministry of Science and Technology,Government of India under contract No.BT/PR5259/AAQ/3/592/2012。
文摘Marine ecosystems provide a wide variety of diverse habitats that frequently promote migration and ecological adaptation.The extent to which the geographic distribution of marine organism has reshaped by human activities remains underappreciated.The limitations intrinsic to morphology-based identification systems have engendered an urgent need for reliable genetic methods that enable the unequivocal recognition of fish species,particularly those that are prone to overexploitation and/or market substitution.In the present study,however,an attempt has been taken to identify two locally adapted fish species,Siganus sutor(Valenciennes,1835)and Seriolina nigrofasciata(Rüppell,1829)of order Perciformes,which happens to be the first record in Odisha coast,Bay of Bengal.The diagnostic characteristics of Siganus sutor are:dorsal fin XIII-10,anal fin VII-9,pectoral fin 15,pelvic fin II-3,while that of Seriolina nigrofasciata dorsal fin VI-I-35,anal fin I-17,pectoral fin 16,pelvic fin 5.All COI barcodes generated in this study were matched with reference sequences of expected species,according to morphological identification.Bayesian and likelihood phylogenetic trees were drawn based on DNA barcodes and all the specimens clustered in agreement with their taxonomic classification at the species level.The phylogeographic studies based on haplotype network and migration rates suggest that both the species were not panmitic and the high-frequency population distribution indicates successful migration.The result of this study provides an important validation of the use of DNA barcode sequences for monitoring species diversity and changes within a complex marine ecosystem.
