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Copyright of Journal of Hydrobiology / Shuisheng Shengwu Xuebao is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Hydrobiology / Shuisheng Shengwu Xuebao is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Investigating the composition and functional analysis of the intestinal microbiome of wild leptocephalus larvae has significant scientific and practical value for predicting their nutritional needs and developing appropriate initial diet. The study identified the species of leptocephalus larvae captured during the 2022 and 2023 scientific expeditions of the "Songhang" research vessel in Western and Central Pacific Ocean using DNA barcoding technology. Additionally, 16S rDNA high-throughput sequencing was employed to sequence the intestinal samples of the leptocephalus larvae, aiming to analyze the intestinal microbial community structure and identify dominant microflora and their related functions. Results showed that 14 of 16 captured leptocephalus larvae were identified to the species level, including Ariosoma majus, Thalassenchelys coheni, Ariosoma megalops, Gnathophis longicauda, Ariosoma meeki, Muraenidae sp. KY17-483, and Gymnothorax zonipectis. The other two leptocephalus larvae were identified to the genus level, Gymnothorax and Gnathophis. Sequencing revealed that the dominant bacterial groups in the intestinal microbiota of pacific leptocephalus larvae were Proteobacteria, Bacteroidetes and Firmicutes. At the genus classification level, Psychrobacter and Acinetobacter exhibited relatively high abundance. However, there were some differences in the intestinal microbiota between different species and sampling sites. Furthermore, functional prediction analysis showed that intestinal microbiota involved in metabolism had the highest relative abundance, and functional pathways related to 'amino acid transport and metabolism' were the most enriched. These data suggested that leptocephalus larvae have a higher demand for protein. Our results preliminarily elucidated the diverse composition of the intestinal microbiota in leptocephalus larvae, providing a reference for studying their feeding habits and the development of starter feeds during the artificial breeding of Japanese eels. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology / Shuisheng Shengwu Xuebao is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The extraction process of Japanese eel skin collagen was optimized using response surface methodology, and its physicochemical properties and allergenicity were investigated. Based on the single-factor experiment, the best extraction process was obtained based on the acid-enzymatic extraction method, with the material-liquid ratio, the concentration of extraction solution and the extraction time as the investigating factors and the collagen yield as the index. The results showed that the collagen contained five bands and belonged to type I collagen, and the percentages of essential amino acids and medicinal amino acids were 19. 61% and 11. 04%, respectively. The thermal transition temperature and thermal denaturation temperature of collagen were 38. 5 and 28. 3 ℃, respectively. The enzyme-linked immunosorbent reaction and simulated gastrointestinal fluid experiments showed that collagen has certain allergenic properties, providing a theoretical basis for further studies on eel skin collagen. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Ocean University is the property of Journal of Dalian Ocean University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of the experiment was to study the effect of Lactobacillus plantarum MH079448 on the muscle quality of Anguilla japonica. A total of 810 juvenile fish were randomly divided into three groups, with three replicates in each group and 90 fish in each replicate. The fish in Lactobacillus plantarum group (LP group) were fed with diet supplemented with Lactobacillus plantarum, while fish in quinac positive control group (OA group) and blank control group (C group) were fed diet supplemented with aseptic saline containing the same amount of Lactobacillus plantarum. Anguilla japonica in OA group were treated with 5 mg/L oxaquic acid antibiotics in a single drug bath for 12 h. The experiment lasted for 28 d. The results showed that the muscle hardness, viscosity, elasticity and chewability of Anguilla japonica in LP group were higher than those in C group (P>0.05). Compared with C group and OA group, the water content in muscle of Anguilla japonica in LP group was significantly increased (P<0.05), the content of delicious amino acids in muscle was significantly increased (P<0.05), the ratio of delicious amino acids to total amino acids was significantly increased (P<0.05), and the content of lysine was significantly increased (P<0.05). The study indicates that adding Lactobacillus plantarum can improve the muscle hardness, viscosity, elasticity and chewability of Anguilla japonica, increase the water content, and increase the content of delicious amino acids in muscle. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology / Shuisheng Shengwu Xuebao is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study was to investigate the effect of cinnamaldehyde on intestinal structure of Anguilla japonica. About 360 000 Anguilla japonica with an average weight of (4.56±0.02) g were selected and randomly divided into control group and test group, with three replicates in each group and 60 000 fish in each replicate. The control group was fed basic diet, the experimental group was fed 250 mg/kg cinnamaldehyde on basis of control group. HE staining and microscopic observation were used to compare the structural differences of intestinal tract between two groups. The experimental period was 30 d. The results showed that the muscle thickness of fish intestine in experimental group was significantly increased, the number and height of villi in foregut and midgut in experimental group were significantly higher than those in control group (P<0.05). The branching structure of the villi was also improved, the number of goblet cells in foregut and midgut of experimental group was significantly lower than that of control group (P<0.05). The study indicates that cinnamaldehyde can effectively improve the structure and morphology of foregut and midgut of Anguilla japonica, and reduce the occurrence of inflammation, but the effect on hindgut is relatively limited. [ABSTRACT FROM AUTHOR]

Anguilla japonica adults with a snout-vent length of (25.91±3.26) cm were randomly sampled from the ponds of monoculture A. japonica (M1) and olyculture A. japonica and Macrobrachium nipponense (M2) and the proliferation site in reservoir (M3) to compare the morphological and quality indices of the adults under the three aquaculture models. Discriminant analysis, cluster analysis, and factor analysis were applied to reveal the differences among the individuals of these three cultured populations. Among the test 21 biological traits and 23 morphological and quality indices, there were significant differences in 15 biological traits and 14 morphological and quality indices between M1 and M2, 19 and 18 between M1 and M3, and 11 and 8 between M2 and M3, respectively. The Euclidean distance between M1 and M2, M1 and M3, and M2 and M3 was 1.433, 3.516, and 2.167, respectively, and the differences were significant. The accumulative variance percentage of the first five (JP2) principal components was 82.1%, and the eigenvalues of these components were all larger than 1. The principal components 1 and 2 could be regarded as fatness factor and movement factor, the other three principal components could be regarded as well-being factor, and the three populations could be clearly separated each other by principal component 1. In discriminant analysis, the five principal components, i.e., body width/anal length, body length /anal length, net volume coefficient, swim bladder coefficient, and liver coefficient, were served as independent variables to establish discriminant functions of the populations, which could clearly distinguish the populations, with the discriminant accuracy and synthetic discriminant accuracy being 100%. [ABSTRACT FROM AUTHOR]