Fishes

17 pages, 1742 KiB

Open AccessArticle

Dietary Probiotic Rhodopseudomonas palustris Formulation Improves Growth Performance, Muscle Composition, Digestive Enzyme Activity, Non-Specific Immunity and Disease Resistance of Juvenile Ivory Shell (Babylonia areolata)

by Xiao Wang, Yao-Peng Lu, Ze-Long Zhang, Pei-Hua Zheng, Jun-Tao Li, Xiu-Xia Zhang, Jia-Jun Li, Heng-Mei Wu and Jian-An Xian

Fishes 2024, 9(12), 522; https://doi.org/10.3390/fishes9120522 - 20 Dec 2024

Abstract

Rhodopseudomonas palustris (RP) are known anaerobic bacteria with probiotic properties containing several bioactive compounds and enzymes that benefit aquatic animals. However, studies on the use of RP on aquatic animal species are limited. This study investigated the effects of dietary supplementation with RP [...] Read more.

Rhodopseudomonas palustris (RP) are known anaerobic bacteria with probiotic properties containing several bioactive compounds and enzymes that benefit aquatic animals. However, studies on the use of RP on aquatic animal species are limited. This study investigated the effects of dietary supplementation with RP formulation on the growth, non-specific immunity, and disease resistance of juvenile ivory shells (Babylonia areolata). The experiment was conducted for 8 weeks, with B. areolata fed a control diet (RP0) and four diets containing four different RP formulations, with doses of 1 (RP1), 5 (RP2), 10 (RP3), and 20 (RP4) g/kg, respectively. Higher levels of R. palustris in the formulation led to increased final weight, weight gain, and specific growth rate in B. areolata. The crude protein content was significantly higher in the RP4 group compared to the RP0 group. However, there was no significant difference in the crude lipid content. Higher levels of R. palustris in the RP4 formulation group increased the trypsin and lipase activities. Dietary supplementation with RP significantly increased the total antioxidant capacity, superoxide dismutase, and catalase activities and decreased the malondialdehyde content in B. areolata. Acid phosphatase and alkaline phosphatase activities were significantly increased in the RP4 group compared to the RP0 group. Dietary RP significantly increased the expression levels of antioxidant-related (superoxide dismutase, Cu/Zn-superoxide dismutase, glutathione S-transferase A-like, ferritin) and immune-related (acid phosphatase, cytochrome c) genes. Higher levels of R. palustris in the formulations RP3 and RP4 increased the survival rate of B. areolata challenged with Vibrio parahaemolyticus. These findings indicate that R. palustris preparation could improve growth performance, muscle composition, and digestive capacity and may act as an immune booster for preventing disease in B. areolata. Full article

(This article belongs to the Special Issue Nutrition and Immune Responses in Aquatic Animals)

► Show Figures

Figure 1

22 pages, 8075 KiB

Open AccessArticle

Effects of Substituting Fishmeal (FM) Diet with a Diet of FM Plus Soy Protein Concentrate (SPC) Supplemented with Essential Amino Acids on the Growth and Gonadal Development of the Olive Flounder (Paralichthys olivaceus)

by Sang Hyun Lee, Yu Jin Sim, Jong-Won Park, Minhwan Jeong, Julan Kim, Seong-Mok Jeong, Dain Lee and Hyun Chul Kim

Fishes 2024, 9(12), 521; https://doi.org/10.3390/fishes9120521 - 19 Dec 2024

Abstract

Numerous studies have explored alternative protein sources to fishmeal (FM) to enhance fish diets, yet limited research exists on their effects on maturation. This study assessed the impact of replacing FM with soy protein concentrate (SPC) supplemented with lysine and methionine on growth [...] Read more.

Numerous studies have explored alternative protein sources to fishmeal (FM) to enhance fish diets, yet limited research exists on their effects on maturation. This study assessed the impact of replacing FM with soy protein concentrate (SPC) supplemented with lysine and methionine on growth and gonadal development in olive flounder (Paralichthys olivaceus). Three diets were tested: a control (Con) diet with 60% FM and two diets replacing FM with 25% (LF1) and 50% (LF2) SPC. Fish were fed to apparent satiation twice daily for 12 months. Growth performance and feed intake were not significantly different between groups. However, the gonadosomatic index varied with diet. Muscle composition and amino acid levels were similar across treatments, though n-3 fatty acids were higher in Con. Spermatogonia was increased, and spermatogenesis was impaired in SPC groups. At 12 months, oocytes in Con diets had absorbed yolk globules, whereas this was absent in SPC groups. Growth-related genes in the brain (growth hormones and insulin-like growth factor) were increased with higher SPC, while follicle-stimulating and luteinizing hormones decreased. Estrogen receptor α levels were elevated in SPC groups. Vitellogenin gene expression in gonads was highest in Con, while liver expression peaked in LF2. The expression of digestive enzymes, chymotrypsin2, and trypsin2 was highest in LF2, while lipase genes were lower. In summary, up to 50% FM replacement with SPC, with amino acid supplementation, supported growth performance and muscle composition without adverse effects on growth in olive flounder but influenced gonadal development. Full article

► Show Figures

Figure 1

10 pages, 1493 KiB

Open AccessArticle

Highlighting the Importance of Correct Sex Identification in Chondrichthyan Genomic Studies, Using the White Shark as an Example

by Szu-Hsuan Lee, Lei Yang and Gavin J. P. Naylor

Fishes 2024, 9(12), 520; https://doi.org/10.3390/fishes9120520 - 18 Dec 2024

Abstract

The increased availability of reference genome assemblies of sharks and rays has contributed greatly to our understanding of their biology, including their sex-determination mechanisms. However, several publicly available genome assemblies of sharks and rays appear to be missing information about the sex of [...] Read more.

The increased availability of reference genome assemblies of sharks and rays has contributed greatly to our understanding of their biology, including their sex-determination mechanisms. However, several publicly available genome assemblies of sharks and rays appear to be missing information about the sex of the source individuals. This can confound the investigation into genetic sex-determining elements and hinder the discovery of sex-specific patterns. Herein, we highlight the importance of clear and accurate sex identification in sharks and rays for future genome assemblies, using an example of a white shark (Carcharodon carcharias) genome, in which the phenotypically assigned sex conflicts with the genetic information. This genome assembly was reported to be sourced from a juvenile female (BioSample: SAMN01915239). We analyzed the assembly by mapping its available genome sequences to the current white shark reference genome assembly and compared the read coverage to sequences collected from other samples. Evidence suggests that this specimen is genetically male, which contradicts its assignment based on phenotype. Therefore, we urge researchers to provide as much accurate information (e.g., sex, sampling localities, and life history) as possible when publishing genome assemblies for sharks and rays (or for any other organism). Full article

► Show Figures

Figure 1

9 pages, 2014 KiB

Open AccessArticle

Osteogenesis and Embryogenesis in Zebrafish Embryo Is Differentially Modulated by Solvents and Prednisolone

by Marta Carnovali, Giuseppe Banfi and Massimo Mariotti

Fishes 2024, 9(12), 519; https://doi.org/10.3390/fishes9120519 - 18 Dec 2024

Abstract

Several molecules and extracts are known to have bone-specific effects. For example, the long-term use of glucocorticoids like prednisolone causes several negative effects including a loss of bone mass. Molecules like prednisolone are usually dissolved in organic solvent which are known to be [...] Read more.

Several molecules and extracts are known to have bone-specific effects. For example, the long-term use of glucocorticoids like prednisolone causes several negative effects including a loss of bone mass. Molecules like prednisolone are usually dissolved in organic solvent which are known to be toxic for zebrafish embryo in certain concentrations. Nevertheless, solvents like dimethyl sulfoxide (DMSO), ethanol and methanol have never been tested for specific skeletal effects during development in dose-dependency. Vitality assay, live fluorescence and bone-specific staining were used to evaluate solvents effects compared to prednisolone. DMSO, ethanol and methanol perturb osteogenesis starting from 1%, 1.5% and 3% respectively, concentrations in which vasculature, length and survival rate appear unaffected. This effect may be due to high sensitivity of the osteogenesis process to external chemical stimuli, especially in the trunk. On the contrary, the negative effect of prednisolone on skeletal development appears more specific since it is found at very low concentrations, far from any other developmental defects. The recommended solvent concentration to be used in zebrafish embryos osteogenesis assay was established in 0.5% for DMSO, 2% for methanol and 0.5% for ethanol. We recommend analyzing both head and trunk mineralization in zebrafish embryo osteogenesis assay. Full article

► Show Figures

Figure 1

1 pages, 137 KiB

Open AccessRetraction

RETRACTED: Choi et al. Distribution Pattern and Brood Parasitism Characteristics of an Endangered Fish, Pseudopungtungia nigra, in the Geum River Basin, South Korea. Fishes 2022, 7, 321

by Jong-Yun Choi, Hany Chang and Seong-Ki Kim

Fishes 2024, 9(12), 518; https://doi.org/10.3390/fishes9120518 - 17 Dec 2024

Abstract

The journal Fishes retracts the article titled “Distribution Pattern and Brood Parasitism Characteristics of an Endangered Fish, Pseudopungtungia nigra, in the Geum River Basin, South Korea” [...] Full article

21 pages, 1599 KiB

Open AccessArticle

Evaluation of Alternative Dietary Ingredients as a Sustainable and Ecological Solution for Meagre (Argyrosomus regius) Production in Earthen Ponds

by Ana Catarina Matias, Hugo Quental-Ferreira, Jorge Dias, Margarida Saavedra, Narcisa Maria Bandarra, Ravi Luna Araújo, Margarida Gamboa, Florbela Soares and Pedro Pousão-Ferreira

Fishes 2024, 9(12), 517; https://doi.org/10.3390/fishes9120517 - 16 Dec 2024

Abstract

The aquaculture sector is developing sustainability measures to address resource limitations and environmental concerns. A key strategy is replacing fishmeal and fish oil with alternatives that can equally sustain fish health, growth, and water quality. This study compared a standard diet (STD) to [...] Read more.

The aquaculture sector is developing sustainability measures to address resource limitations and environmental concerns. A key strategy is replacing fishmeal and fish oil with alternatives that can equally sustain fish health, growth, and water quality. This study compared a standard diet (STD) to an alternative diet (ALT) containing sustainable ingredients, such as plant-based proteins and animal by-products, for meagre raised in earthen ponds within a polyculture system. Over 150 days, 5400 meagre juveniles (174.9 ± 32.8 g) were fed these diets. Fish on the ALT diet showed superior growth, likely due to higher dietary protein content and reduced protein degradation in liver and muscle, leading to increased protein content and reduced levels of dry matter, lipid, ash, energy, and phosphorous. While muscle cohesiveness was affected, fiber area and density were unchanged. ALT-fed fish exhibited higher saturated (SFA) and polyunsaturated (PUFA) fatty acids, reflecting the diet. Water quality indicators, including ammonia, nitrites, nitrates, and phosphates, were similar across diets, though chlorophyll a was higher in ponds with STD-fed fish. Overall, the ALT diet emerges as a sustainable alternative to the STD diet, maintaining or enhancing protein levels while reducing fishmeal usage. This approach effectively supports meagre growth and fillet quality without significant additional environmental impact. Full article

► Show Figures

Graphical abstract

13 pages, 5220 KiB

Open AccessArticle

Insights into ‘Srdelara’ Purse Seines: Landing Composition and Trophic Relationships in the Pelagic Food Web

by Barbara Zorica, Daria Ezgeta-Balić, Lana Schmidt and Marija Šestanović

Fishes 2024, 9(12), 516; https://doi.org/10.3390/fishes9120516 - 16 Dec 2024

Abstract

This study analysed commercial ‘Srdelara’ purse seine landings in the Central Eastern Adriatic from November 2020 to March 2022. The observed commercial landings demonstrated typical seasonal variations, with a peak from September to November and the lowest landings recorded from spring to early [...] Read more.

This study analysed commercial ‘Srdelara’ purse seine landings in the Central Eastern Adriatic from November 2020 to March 2022. The observed commercial landings demonstrated typical seasonal variations, with a peak from September to November and the lowest landings recorded from spring to early summer. Sardines dominated the purse seine landings, comprising 97.9% of the total landing, followed by anchovies at 1.3%, with occasional by-catches or other species. Biological analysis involved collecting samples of eight pelagic fish species (sardine, anchovy, round sardinella, Atlantic bonito, Atlantic horse mackerel, Atlantic mackerel, chub mackerel and bogue) captured by the aforementioned fishing gear during the study period. The length frequency distributions of the investigated fish species were predominantly unimodal, with the exception of the Atlantic horse mackerel. Moreover, the length–weight relationships indicated isometric growth for each examined species. Stable isotope analysis revealed overlapping isotopic niches among the eight analysed fish species, with estimated mean trophic positions ranging from 3.0 to 4.7, indicating consumption of prey across approximately two trophic levels. The round sardinella and bogue had the smallest isotopic niche, while Atlantic mackerel had the widest one. This study highlights the need for further research to evaluate the observed overlap among pelagic species, particularly between small and medium-sized pelagic fish, as this interaction could significantly impact their biomass. Determining the extent of this overlap is crucial for improving management strategies and ensuring the sustainability of pelagic fish stocks in the Adriatic Sea. Full article

(This article belongs to the Section Biology and Ecology)

► Show Figures

Figure 1

15 pages, 10726 KiB

Open AccessArticle

Pathological Progress of Two Types of Nodules in Micropterus salmoides Infected with Nocardia seriolae

by Chengwei Li, Wenhui Wang, Fan Wu, Hao Pu and Lei Liao

Fishes 2024, 9(12), 515; https://doi.org/10.3390/fishes9120515 - 16 Dec 2024

Abstract

The typical clinical signs of Nocardia seriolae infection include white nodules, ranging from 0.1 to 10 mm in diameter, distributed across various internal organs. However, the structural composition of nodules of different sizes remains unexplored. In this study, natural cases of largemouth bass [...] Read more.

The typical clinical signs of Nocardia seriolae infection include white nodules, ranging from 0.1 to 10 mm in diameter, distributed across various internal organs. However, the structural composition of nodules of different sizes remains unexplored. In this study, natural cases of largemouth bass (Micropterus salmoides) were collected, and pathogenic bacteria were isolated and confirmed through a re-infection experiment. The isolated bacteria were identified as N. seriolae through 16S rRNA and gyrB gene sequencing. Healthy largemouth bass were infected with the isolate using an immersion infection and observed continuously over 56 days. Samples were successfully obtained from the incubation, prodromal, symptomatic, and convalescent phases, allowing for gross, histological, and ultrastructural observations of nodular lesion progression. Results demonstrated two types of nodular lesions: necrotic foci and granulomas. Macroscopically visible nodules larger than 1 mm, observed primarily in the liver, spleen, kidney, and muscle tissues of moribund fish, exhibited coagulative necrosis and were identified as the principal cause of mortality. Conversely, granulomas, with diameters less than 1 mm, were consistently present in the spleen, kidney, and liver during the symptomatic and convalescent phases. Full article

(This article belongs to the Special Issue Interactions Between Fish and Pathogens in Aquaculture—2nd Edition)

► Show Figures

Figure 1

17 pages, 3293 KiB

Open AccessArticle

Effects of Mango Seed (Mangifera indica) Powder on Growth Performance, Immune Response, Gut Morphology, and Gene Expression of Nile Tilapia (Oreochromis niloticus)

by Camilla Maria Fontana, Md Afsar Ahmed Sumon, Supreya Wannavijit, Anisa Rilla Lubis, Nuttapon Khongdee, Nguyen Vu Linh, Yuthana Phimolsiripol, Seyed Hossein Hoseinifar and Hien Van Doan

Fishes 2024, 9(12), 514; https://doi.org/10.3390/fishes9120514 - 16 Dec 2024

Abstract

This study explored the effects of mango seed (MS) powder supplementation on the growth, immune response, gene expression, and intestinal morphology of Nile tilapia (Oreochromis niloticus) over an 8-week period. A total of 300 Nile tilapia fingerlings (average weight of 15.29 [...] Read more.

This study explored the effects of mango seed (MS) powder supplementation on the growth, immune response, gene expression, and intestinal morphology of Nile tilapia (Oreochromis niloticus) over an 8-week period. A total of 300 Nile tilapia fingerlings (average weight of 15.29 ± 0.05 g) were divided into five treatment groups and fed either a basal diet or one of four experimental diets containing MS powder at concentrations of 10 (MS10), 20 (MS20), 40 (MS40), and 80 (MS80) g kg⁻¹. The results demonstrated that Nile tilapia fed MS-supplemented diets experienced significant improvements (p < 0.05) in weight gain (WG), specific growth rate (SGR), and survival rate (SR) compared to the control group (0 g kg⁻¹ MS). The MS-treated groups also showed a significant increase (p < 0.05) in the height and branching of intestinal villi along the entire length of the intestine, as well as a significantly higher villus-to-crypt depth ratio (V/C), indicating enhanced intestinal health and functionality. Moreover, although MS supplementation did not increase peroxidase activity, it did lead to a significant increase (p < 0.05) in the activity of skin mucus and serum lysozyme, along with upregulated gene expression of immune-related (IL-1, IL-8, and LBP) and antioxidant genes (GST-α, GPX, and GSR). Polynomial regression analysis identified an optimal MS dosage of 36.43–45 g kg⁻¹ for effectively improving growth, immunity, and immuno-oxidant gene expression in Nile tilapia. These results emphasize mango seed (MS) as a promising natural supplement for improving the diet of Nile tilapia and, potentially, other freshwater fish widely used in aquaculture. Full article

(This article belongs to the Special Issue Therapeutic Potential of Probiotics, Prebiotics, and Synbiotics in Advancing Aquaculture Health and Performance)

► Show Figures

Graphical abstract

25 pages, 6604 KiB

Open AccessFeature PaperArticle

Age- and Size- Based Reproductive Potential of Gray Snapper (Lutjanus griseus) in the Eastern Gulf of Mexico

by Ashley Wechsler, Debra J. Murie and Eric Bovee

Fishes 2024, 9(12), 513; https://doi.org/10.3390/fishes9120513 - 15 Dec 2024

Abstract

Relatively little is known about size- and age-based reproductive characteristics of Gray Snapper (Lutjanus griseus) despite a large recreational fishery along the west coast of Florida in the Southeastern U.S.A. The purpose of this study was therefore to determine the spawning [...] Read more.

Relatively little is known about size- and age-based reproductive characteristics of Gray Snapper (Lutjanus griseus) despite a large recreational fishery along the west coast of Florida in the Southeastern U.S.A. The purpose of this study was therefore to determine the spawning parameters of Gray Snapper and to quantify female reproductive potential on an age- and size-basis. From 2022 to 2023, 4563 Gray Snapper were collected off the west coast of Florida. Gray Snapper were observed to be actively spawning from late May to early September; however, the percent of females spawning in May and September were both <3%. Batch fecundity for 12 hydrated females showed a hyperallometric relationship with size and age. The spawning fraction also increased disproportionately with female length and age, suggesting older, larger females spawn in greater proportions and more often than younger, smaller females. For females, the length and age at 50% physiological maturity was 292 mm total length (TL) and 2.9 years, and those at 50% functional maturity was 301 mm TL and 3.2 years. Male Gray Snapper reached 50% sexual maturity at 259 mm TL and 1.8 years. The minimum size limit of 10 inches (254 mm) TL in Florida state waters appears to be too low to protect maturing females in particular. These new spawning metrics should be incorporated into future stock assessments to improve estimates of Gray Snapper reproductive output, stock status, and management. Full article

► Show Figures

Figure 1

10 pages, 9807 KiB

Open AccessArticle

The Heme Cavity Is Essential for the Peroxidase and Antibacterial Activity of Homodimer Hemoglobin from the Blood Clam Tegillarca granosa

by Lili Pu, Shuting Dai, Zongming Wu, Sufang Wang and Yongbo Bao

Fishes 2024, 9(12), 512; https://doi.org/10.3390/fishes9120512 - 15 Dec 2024

Abstract

This study investigates the essential role of the heme cavity in the peroxidase and antibacterial activities of homodimeric hemoglobin (Tg-HbI) from the blood clam Tegillarca granosa. After treatment with sodium dodecyl sulfate (SDS), the peroxidase and antibacterial activities of the Tg-HbI were [...] Read more.

This study investigates the essential role of the heme cavity in the peroxidase and antibacterial activities of homodimeric hemoglobin (Tg-HbI) from the blood clam Tegillarca granosa. After treatment with sodium dodecyl sulfate (SDS), the peroxidase and antibacterial activities of the Tg-HbI were significantly inhibited, with the degree of inhibition correlating positively with the SDS concentration. Fluorescence spectroscopy, UV-Vis spectroscopy, and molecular docking analysis further revealed that SDS interacts with key amino acid residues (e.g., His70 and His102) in the heme cavity of Tg-HbI, causing conformational changes that disrupt the internal hydrophobic interactions, thus inhibiting its function. This study confirms that the antibacterial effect of Tg-HbI is mediated through its peroxidase activity and that the heme cavity plays a critical role in maintaining this activity. These findings lay a foundation for further research on the immune defense functions of hemoglobin and provide new insights into the mechanisms of environmental adaptation in T. granosa. Full article

(This article belongs to the Special Issue Shellfish Genetics and Breeding for Aquaculture)

► Show Figures

Figure 1

15 pages, 3236 KiB

Open AccessArticle

Testing of the Taxonomic Diagnosis of Zebrus pallaoroi Kovačić, Šanda & Vukić, 2021 (Actinopteri: Gobiiformes: Gobiidae), on a Large Sample from the Western Mediterranean

by Marcelo Kovačić, Lucas Bérenger and Julien P. Renoult

Fishes 2024, 9(12), 511; https://doi.org/10.3390/fishes9120511 - 14 Dec 2024

Abstract

A large sample of 65 individuals of the recently described goby Zebrus pallaoroi was collected in France. The species identity of these individuals was confirmed based on morphology. In addition, the species identity was validated through genetic analysis for one of the two [...] Read more.

A large sample of 65 individuals of the recently described goby Zebrus pallaoroi was collected in France. The species identity of these individuals was confirmed based on morphology. In addition, the species identity was validated through genetic analysis for one of the two specimens collected from the new depth records for the species. The diagnostic characters of Z. pallaoroi, originally based on a limited number of type specimens, were tested on this larger sample and critically analyzed. The diagnostic characters of Z. pallaoroi were revised, and recommendations were made for improving the study of diagnostic characters in gobiid species description, particularly when based on small sample sizes. The record of Z. pallaoroi in the western Mediterranean significantly expands its known geographic range, increases the maximum recorded depth of the species, and reveals syntopic co-occurrence with its phylogenetically closest relatives. Full article

(This article belongs to the Special Issue Integrating Morphology and Molecular Phylogenies for Elucidating Fish Diversity and Complex Evolutionary Patterns)

► Show Figures

Figure 1

17 pages, 3590 KiB

Open AccessArticle

DNA Barcodes for Identifying Fish Egg Species Diversity in Summer and Autumn in the Southwest Daya Bay, China

by Shile Zheng, Jianbin Lin, Fengxia Wu, Yiyong Rao, Jinrun Wang, Siyuan He, Honghui Huang and Gang Hou

Fishes 2024, 9(12), 510; https://doi.org/10.3390/fishes9120510 - 13 Dec 2024

Abstract

Identifying fish eggs and understanding fish reproductive periods are necessary for informed fishery management. However, accurate the identification of fish eggs is difficult because eggs have few distinct characters, and their morphology varies ontogenetically. Using cytochrome c oxidase subunit I, we identified fish [...] Read more.

Identifying fish eggs and understanding fish reproductive periods are necessary for informed fishery management. However, accurate the identification of fish eggs is difficult because eggs have few distinct characters, and their morphology varies ontogenetically. Using cytochrome c oxidase subunit I, we identified fish eggs from ichthyoplankton samples collected in the summer and autumn of 2021 from southwestern Daya Bay, China. Of 567 fish eggs, 498 high-quality cytochrome c oxidase subunit I sequences were obtained, of which 116 eggs (23.3%) could be identified to species; 364 (73.1%) to genus, family and/or order; and 18 (3.6%) could not be assigned. Of 51 apparent taxa, 46 were identified to 6 orders, 19 families, and 30 genera; 20 to the species and 25 to the genus and/or family, and 1 to the order. Among these 51 taxa, 35 occurred in summer, 29 occurred in autumn, and 13 occurred in both seasons; 22 occurred only in summer and 16 only in autumn, indicating species-specific spawning periods. High-resolution photographs of eggs are provided to facilitate subsequent identification based on morphology. These results will facilitate the identification of spawning grounds and their protection, to more holistically manage fishery resources in Daya Bay, China. Full article

(This article belongs to the Special Issue Assessment and Management of Fishery Resources)

► Show Figures

Figure 1

14 pages, 2008 KiB

Open AccessArticle

The Impact of Rutin on Heat Stress Response of Hybrid Fish (Carassius auratus cuvieri ♀ × Carassius auratus Red var. ♂)

by Shuailin Chen, Die Li, Xiaojuan Cui, Jia Xu, Yujing Li and Yuandong Sun

Fishes 2024, 9(12), 509; https://doi.org/10.3390/fishes9120509 - 13 Dec 2024

Abstract

Heat stress is a major environmental stressor that affects fish metabolism, growth, and death rates. This research examined the impact of dietary rutin addition (0, 100, 300, or 500 mg/kg) for 60 days on juvenile hybrid fish (Carassius auratus cuvieri, WCC, [...] Read more.

Heat stress is a major environmental stressor that affects fish metabolism, growth, and death rates. This research examined the impact of dietary rutin addition (0, 100, 300, or 500 mg/kg) for 60 days on juvenile hybrid fish (Carassius auratus cuvieri, WCC, ♀ × Carassius auratus red var, RCC, ♂, WR) (27.97 ± 0.56 g) under heat stress conditions (32 ± 1 °C for 48 h). The analysis focused on blood parameters, oxidative stress biomarkers, and hepatic hsp70 and hsp90 gene expression in WR. The results demonstrated that rutin supplementation elevated blood glucose levels and the liver activities of glutathione reductase, glutathione peroxidase, catalase, and total superoxide dismutase in comparison to the control group. Additionally, rutin supplementation also significantly reduced serum cortisol and hepatic malondialdehyde levels while upregulating hepatic hsp70 and hsp90 gene expression. These findings suggest that rutin supplementation enhances antioxidant responses and alleviates the impact of heat stress on fish physiological and biochemical markers and heat shock protein gene expression. Full article

(This article belongs to the Special Issue Stress Physiology in Aquatic Animals)

► Show Figures

Figure 1

17 pages, 931 KiB

Open AccessArticle

Effect of Photoperiod on Nutritional Quality of Muscle and Lipid Metabolism of Litopenaeus vannamei

by Yingying Fang, Fan Fei, Fulu Guo, Chengliang Zhu, Xiaoqiang Gao, Wenyang Li, Hongjun Yang, Yan Sun, Chuanxin Zhang and Baoliang Liu

Fishes 2024, 9(12), 508; https://doi.org/10.3390/fishes9120508 - 12 Dec 2024

Abstract

Photoperiod serves as a significant environmental signal for organisms and plays a critical role in regulating their metabolic processes. This research aimed to investigate the lipid metabolism and nutritional quality of adults Litopenaeus vannamei (wet weight: 11.27 ± 0.73 g, body length: 12.45 [...] Read more.

Photoperiod serves as a significant environmental signal for organisms and plays a critical role in regulating their metabolic processes. This research aimed to investigate the lipid metabolism and nutritional quality of adults Litopenaeus vannamei (wet weight: 11.27 ± 0.73 g, body length: 12.45 ± 0.42 cm) under five photoperiods (0L:24D, 8L:16D, 12L:12D, 16L:8D, and 24L:0D) for 40 days in recirculating water systems (RASs). The 24L:0D group increased lipid metabolism, as indicated by increased lipid metabolism enzyme levels and related gene expression linked to lipogenesis. Additionally, shrimp in the 24L:0D exhibited the highest value of crude fat. The 0L:24D showed a significantly reduced content of crude fat compared with the 8L:16D and 12L:12D. In 24L:0D, the content of total essential amino acids (TEAAs), total hydrolyzed essential amino acids (THEAAs), and total non-essential amino acids (TNEAAs) increased significantly. Similarly, the content of polyunsaturated fatty acids (PUFAs) in 24L:0D was also higher than in other groups. Conversely, 0L:24D resulted in lower metabolic activity and a reduction in PUFA content. In conclusion, prolonging light could benefit shrimp cultivation. This study thoroughly examined the effects of varying photoperiods on muscle quality and lipid metabolism in L. vannamei, providing essential insights for the improvement of indoor aquaculture environments. Provision of light for 24 h improves production but has some adverse effects on animal welfare, so a 16 h light cycle is recommended. Full article

(This article belongs to the Special Issue Fish Farming in Recirculating Aquaculture Systems)

► Show Figures

Figure 1

26 pages, 4607 KiB

Open AccessReview

Digestive Physiology, Nutrition and Feeding of Arapaima gigas: A Review

by Alfredo Ruben Palomino Ramos and Francisco Javier Moyano López

Fishes 2024, 9(12), 507; https://doi.org/10.3390/fishes9120507 - 11 Dec 2024

Abstract

The Arapaima gigas, a native fish species in the Amazon basin, presents particular biological and zootechnical characteristics, along with substantial economic value, that make it a promising candidate for its production within intensive aquaculture systems. To date, different studies have been conducted [...] Read more.

The Arapaima gigas, a native fish species in the Amazon basin, presents particular biological and zootechnical characteristics, along with substantial economic value, that make it a promising candidate for its production within intensive aquaculture systems. To date, different studies have been conducted to (a) increase the understanding of its digestive physiology in relation to feeding habits, (b) determine its nutritional requirements at different developmental stages, (c) assess the potential use of alternative ingredients in diets, and (d) elucidate its feeding behavior patterns in captivity to improve feeding strategies. However, important gaps still remain in the available information related to the above-mentioned aspects that compromise the formulation of efficient and balanced aquafeeds used in the different production phases of this species. This article provides a comprehensive review of the current state of knowledge regarding digestive physiology, nutritional requirements and feeding strategies of A. gigas with the main objective of identifying areas that require further research for application in developing suitable and sustainable feeds for the species. Full article

► Show Figures

Figure 1

16 pages, 6362 KiB

Open AccessArticle

Oligochitosan Mitigates Vibrio harveyi Infection in Hybrid Groupers (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀) by Modulating Immune Responses and Disease-Related Pathways

by Fei Shi, Lixin Ma, Zhilong Chen, Hao Zhao, Cuiyun Zou, Li Lin and Zhendong Qin

Fishes 2024, 9(12), 506; https://doi.org/10.3390/fishes9120506 - 11 Dec 2024

Abstract

Vibrio harveyi is an important pathogen causing enteritis in hybrid groupers. However, its effects on the intestinal microbiota and the regulatory effects of oligochitosan on Vibrio-infected groupers are unclear. In this study, we investigated the effects of infection with V. harveyi and [...] Read more.

Vibrio harveyi is an important pathogen causing enteritis in hybrid groupers. However, its effects on the intestinal microbiota and the regulatory effects of oligochitosan on Vibrio-infected groupers are unclear. In this study, we investigated the effects of infection with V. harveyi and oligochitosan administration on the growth performance, immune responses, and intestinal transcriptome profiles of hybrid groupers during a 60-day rearing period. Growth parameters were reduced in Vibrio-infected groupers, while oligochitosan improved the body weight. Biochemical analysis showed reduced antioxidant enzyme activity and increased lipid peroxidation in Vibrio-infected groupers, which were consequently improved by oligochitosan. Transcriptome analysis was used to identify differentially expressed genes in the disease-related and immune system pathways that significantly accumulated in the treatment groups. An evaluation of the immune response showed a significant down-regulation of proinflammatory cytokines, antioxidant genes, and tight-junction proteins in Vibrio-infected groupers, which was partially restored by oligochitosan. Additionally, intestinal apoptosis, indicated by TUNEL signaling, was observed to significantly increase in Vibrio-infected groupers and was subsequently alleviated by oligochitosan supplementation. These results demonstrate the detrimental effects of V. harveyi infection on the growth and immune function of hybrid groupers and the potential of oligochitosan to attenuate these effects. Full article

► Show Figures

Figure 1

18 pages, 1331 KiB

Open AccessArticle

Economic Analysis of Red Tilapia (Oreochromis sp.) Production Under Different Solar Energy Alternatives in a Commercial Biofloc System in Colombia

by Daniel Leonardo Cala-Delgado, Jesaías Ismael da Costa and Fabiana Garcia

Fishes 2024, 9(12), 505; https://doi.org/10.3390/fishes9120505 - 11 Dec 2024

Abstract

The study investigates the economic aspects of red tilapia (Oreochromis sp.) production using biofloc technology under different electrical energy sources. Conducted at the El Vergel Fish Farming Association in Arauca, Colombia, the study examines four energy treatments: conventional energy (CE), combined conventional [...] Read more.

The study investigates the economic aspects of red tilapia (Oreochromis sp.) production using biofloc technology under different electrical energy sources. Conducted at the El Vergel Fish Farming Association in Arauca, Colombia, the study examines four energy treatments: conventional energy (CE), combined conventional and photovoltaic energy (CPVE), full photovoltaic energy (PVE), and simulation of photovoltaic energy generating surplus for nighttime use (PVES). The water quality and zootechnical performance met the species requirements, with dissolved oxygen decreasing as fish size increased. The PVE treatment had the highest initial investment due to solar panels and battery costs, but it also had the lowest operating energy costs. However, the overall costs of the PVE treatment increased due to depreciation and maintenance. Feed was the largest production cost, followed by labor in most treatments, while depreciation was a major cost for the PVE treatment. The total operating cost (TOC) of the photovoltaic energy systems (PVE and PVES) was lower compared to that of conventional energy (CE), with PVES showing the highest cost savings. The reduction in energy costs highlights the potential for solar energy systems to enhance the economic viability of aquaculture production, making these systems a favorable option for sustainable production in the long term. Full article

(This article belongs to the Special Issue Biofloc Technology in Aquaculture)

► Show Figures

Graphical abstract

14 pages, 1694 KiB

Open AccessArticle

Effects of Suwari Suppression and Enzyme Inhibitors on Water Holding Capacity of Alaska Pollock (Theragra chalcogramma) Surimi Gel and Its Improvement by Modified Grinding Method

by Yusa Nakamura and Kigen Takahashi

Fishes 2024, 9(12), 504; https://doi.org/10.3390/fishes9120504 - 10 Dec 2024

Abstract

The processes before heating in surimi gel production, such as grinding and molding, are performed below 10 °C to prevent unintentional protein gelation (suwari or setting) catalyzed by endogenous transglutaminase. Adding transglutaminase and protease inhibitors contributes to obtaining surimi gel with superior breaking [...] Read more.

The processes before heating in surimi gel production, such as grinding and molding, are performed below 10 °C to prevent unintentional protein gelation (suwari or setting) catalyzed by endogenous transglutaminase. Adding transglutaminase and protease inhibitors contributes to obtaining surimi gel with superior breaking properties after suwari suppression. However, the impact of suwari suppression and enzyme inhibitors on the water holding capacity (WHC) of surimi gel remains unclear. This study investigated changes in the WHC of surimi gel during long-term suwari suppression by adding enzyme inhibitors at 25 °C and clarified its mechanism. The expressible drip of samples with EGTA, a transglutaminase inhibitor, increased with heating time at 25 °C to 12.3% owing to proteolysis. The use of N-ethylmaleimide and E-64, cysteine protease inhibitors, further increased the expressible drip of samples (18.9–19.4%) because of protein conformational changes which were observed by DSC analysis and salt solubility measurement. However, this increase was inhibited by a modified grinding method where NaCl was mixed with surimi before adding enzyme inhibitors. This modified method prevented the reduction in protein salt solubility due to protein conformational changes, thereby maintaining WHC in surimi gel with suwari suppression. Full article

(This article belongs to the Section Processing and Comprehensive Utilization of Fishery Products)

► Show Figures

Figure 1

Journal Description

Fishes

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI