Volume 76, Issue 2, 2024

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    Mannan oligosaccharide improves antioxidant capacity, non-specific immunity and protection against Vibrio disease and Typhoon stress in Trachinotus ovatus juveniles
    ( 2024) Chen, Zihan ; Wu, Yue ; Cai, Yan ; Chen, Xin ; Zhou, Yongcai ; Cao, Zhenjie ; Li, Jianlong ; Wang, Shifeng
    This study examined the impact of varying doses of mannan oligosaccharide (MOS) supplementation on antioxidant defense, non-specific immunity, resistance to typhoon stress, and resistance to disease in Trachinotus ovatus. Fish groups C, M1, M2, and M3 were fed 1%, 0.3%, 0.6%, and 1% MOS-supplemented feed, respectively. On the 28th and 56th day of the feeding trial, samples from all groups were taken to measure the antioxidant and non-specific immunity parameters and challenged with Vibrio harvey. On the 32nd day, a typhoon hit the experimental site, and the survival rates of all groups were calculated. Results showed that on the 28th day, groups M2 and M3 showed considerably higher levels of antioxidant abilities (T-AOC), and groups M1 and M2 showed significantly enhanced non-specific immunity (AKP, LZM, and TP) levels than those of group C (p < 0.05). All MOS groups had significantly lower cumulative mortality following the challenge test and typhoon stress than the control group (p < 0.05). On the 56th day, groups M2 and M3 showed significantly enhanced antioxidant ability (CAT) compared to the control group. Only one non-specific immunity parameter increased significantly in groups M2 and M3 (p < 0.05). After the challenge test, only group M3 exhibited a significantly declined cumulative mortality rate compared to the control groups (p < 0.05). In summary, supplementation of MOS at dose 0.6% (M2) for 28 days showed the best overall improving effects on the antioxidant capacity, non-specific immunity, disease resistance, and typhoon stress resistance in T. ovatus juveniles.
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    Effects of dietary β-sitosterol supplementation on growth performance, antioxidant ability, and disease resistance in largemouth bass Micropterus salmoides
    ( 2024) Xing, Yangyang ; Zhang, Liping ; Xue, Mingyang ; Liu, Wei ; Jiang, Nan ; Li, Yiqun ; Chen, Jianwu ; Fan, Yuding ; Zhou, Yong ; Meng, Yan
    β-sitosterol, as the most abundant phytosterol, has been shown to exert multiple biological roles in in vitro and in vivo animal studies. Largemouth bass (Micropterus salmoides) is an economical freshwater-farmed species widely cultivated in China due to its nutritious and delicious meat. This study investigated the effects of dietary β-sitosterol supplementation on largemouth bass farming. In the study, largemouth bass were fed with five levels of β-sitosterol (0, 20, 40, 80, and 160 mg/kg) supplementation in a commercial feed for four weeks. The growth performance, antioxidant ability, intestinal structure, immune-related gene expression, and resistance to pathogens such as Aeromonas hydrophila and largemouth bass virus (LMBRaV) were detected. The results revealed that β-sitosterol supplementation in feed increased the weight gain rate of largemouth bass, with 40 mg/kg supplementation displaying the best effect. The serum biochemical indices all showed an increase, including glucose and alkaline phosphatase. The intestinal villus length and muscularis propria thickness also increased, accompanied by elevated digestive enzyme activities, which promoted digestion and absorption of nutrients. Meanwhile, the levels of total cholesterol, aspartate aminotransferase, and alanine aminotransferase in serum decreased, indicating reduced liver damage. In addition, β-sitosterol supplementation effectively enhanced the antioxidant capacity of largemouth bass by decreasing malondialdehyde and elevating superoxide dismutase. Immune-related gene expression also changed. Pathogen infection tests revealed that β-sitosterol supplementation in feed had a certain protective effect against infection in largemouth bass, with the protection rate against A. hydrophila being higher than LMBRaV. The 40 mg/kg β-sitosterol supplementation group exhibited the best results. Collectively, the results revealed that the β-sitosterol can promote growth, improve enzyme activity, stimulate intestinal digestion, increase immune gene expression, and induce disease resistance in largemouth bass, with the optimal supplementation dosage being 40 mg/kg. β-sitosterol might be an excellent feed additive in aquaculture.
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    Identification of Acinetobacter schindleri isolated from Chinese giant salamanders (Andrias davidianus)
    ( 2024) Wang, Cheng ; Xie, Yixing ; Deng, Zhiyong ; Yuan, Huanyan ; Tian, Mingzhu ; Mao, Pan ; Zhou, Yong ; Wei, Ying
    At a particular aquaculture facility in Zhangjiajie in China, the Chinese giant salamander (Andrias davidianus) exhibited analogous clinical manifestations, culminating in sequential mortalities. This study used rigorous aseptic sampling methods to isolate bacteria from the affected liver of salamanders to determine the causative agent behind the decline in amphibians. A bacterial pathogen was isolated from diseased A. davidianus, and the strain was named DN-3. This isolate was subjected to bacterial identification, antibiotic susceptibility assays, reinfection experiments, and biochemical profiling. The isolated bacterial strain was definitively identified as Acinetobacter schindleri using 16S rRNA sequence analysis and biochemical identification. Antibiotic susceptibility testing revealed that this isolate was susceptible to neomycin, macrolides, doxycycline, piperacillin, nitrofurantoin, and carbenicillin. Subsequent reinfection assays, in which varying concentrations of the bacterial inoculum were administered to healthy salamanders, confirmed that the pathogen elicited varying degrees of morbidity or mortality within an eight-day observation period. The median lethal dose (LD50) of A. schindleri DN-3 for A. davidianus was calculated to be 6.25×104 CFU/mL. This result supports the significant pathogenicity of the strain for A. davidianus. The findings of this study provide empirical insights into the clinical management and epidemiological control of diseases affecting A. davidianus.
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    Construction and reflections on the disease prevention and control system of aquatic organisms based on management perspective
    ( 2024) Li, Cai-Yun ; Li, Xiao-Ai ; Li, Li ; Lou, Yi-Chun ; Yu, Cheng-Song ; Xu, Hui-Ping ; Xu, Tao
    Disease prevention and control are a crucial aspect of fishery management, as they ensure the sustainability of aquacultural systems. With a specific focus on Shandong Province, China, this study outlines the occurrence of diseases in aquatic organisms. It summarizes dynamics that drive disease prevention and control and supports technology, work mode, and emergency prevention and control. In addition, this study also delves into the role of epidemic prevention and control institutions, the upgrading of the social service of disease prevention systems, and insufficient technical support for new species and models. Overall, the findings outlined in this study are intended to achieve the following aims: enhance organizational management of disease prevention and control, standardize the implementation of social services, improve research into prevention and control technologies, and highlight the importance of information technology in disease prevention and control. Based on practical aquaculture production, our aim is to comprehensively analyze the situation of the construction of a disease prevention and control system, strengthen guidance on epidemic prevention technologies, establish a robust animal epidemic prevention system, and propose development strategies, serving as a reference for competent authorities to enhance the disease prevention and control of aquatic organisms.
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    A First Look at Genetic Diversity of Metapenaeus ensis Populations in Tam Giang – Cau Hai Lagoon, Vietnam
    ( 2024) Xuan Huy, Nguyen ; Ty, Nguyen ; Giang, Tran Van ; Phuong, Tran Vinh
    This study investigates the genetic diversity and population structure of the greasyback shrimp, Metapenaeus ensis (De Haan, 1844), within the Tam Giang – Cau Hai lagoon, Vietnam, by analyzing mtCOI genes from 91 individuals collected across four populations in nine sampling locations. High genetic diversity was found, with 34 unique haplotypes and 38 genetic variations identified. Most genetic variation occurred within populations (AMOVA), suggesting high gene flow. Low and non-significant Fst values and close genetic distances confirmed minimal differentiation among populations. These findings provide the first insights into M. ensis population genetics in this lagoon, informing conservation and management efforts. Understanding genetic diversity is crucial for sustainable management and conservation of marine species. This research aids in understanding population resilience, potential impacts of overfishing, and may assist in developing sustainable harvest strategies of this economically important shrimp species.
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    Cercariae from snails in rice fields and canal supplying water directly to Trichopodus microlepis fish cultured in earthen ponds in Binh Chanh district, Ho Chi Minh City, Vietnam.
    ( 2024) Thien, Pham C. ; Manh, Ho T. ; Quyen, Duong T. ; Xuan, Nguyen T.L. ; Lan, Nguyen T. ; Hung, Nguyen M.
    Snails are the first intermediate host in the life cycle of trematodes. Previous research found that Trichopodus microlepis fish, cultured in earthen ponds in Tan Nhut Commune, Binh Chanh District, Ho Chi Minh City, Vietnam had a high infection rate with metacercariae of Centrocestus formosanus and Procevorum sp. It is necessary to investigate whether habitats supplying water to the ponds may contribute to the transmission by carrying intermediate hosts and/or cercariae into these ponds or not. A study of cercariae and snail composition in rice fields and canal supplying water directly to these Trichopodus microlepis ponds was carried out with six samplings in the years 2022 and 2023. A total of 1,151 snails were collected, and nine snail species belonging to 8 genera and 6 families were identified. Three snail species in both rice fields and canal were infected with trematode (cercariae stage) including Bithynia siamensis, Lymnaea viridis and Indoplanorbis exustus. The overall prevalence in the dry season (25.9%) was significantly higher than in the wet season (10.6%) (P<0.05). Three cercariae morphotypes were recovered from snails: xiphidio (in all three snails), echinostome (in Lymnaea viridis and Indoplanorbis exustus), and pleurolophocercous in Bithynia siamensis. This finding shows that Bithynia siamensis is one of the infected sources for Trichopodus microlepis fish cultured in ponds, as pleurolophocercous is also the cercariae in the family of Heterophyidae (including Centrocestus formosanus and Procevorum sp.). Further research should be done to clarify the transmission of fish-borne zoonotic diseases to cultured Trichopodus microlepis in other habitats including the actual fishponds, and sources of trematodes in order to produce Trichopodus microlepis free of metacercariae, contributing to clean aquaculture development and safe food for local people in the area.
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    Length-weight relationships and biometry analysis of saddled seabream, Oblada melanurus (Linnaeus, 1758) in İzmir Bay (Central Aegean Sea of Türkiye)
    ( 2024) Kara, Ali ; Bayhan, Bahar ; Taylan, Burcu ; Babaoğlu, Ali Özcan
    The present study presents length-weight, length-length, length-girth relationships, and biometry of male and female specimens of saddled seabream, Oblada melanurus(Linnaeus, 1758), in the Turkish Aegean Sea. The length-length and length-weight relationships were calculated by measuring 516 individuals. The total length values of all male and female O. melanurus specimens were in the range of 17.2-30.7 and 18.5-30.0 cm, respectively, and the mean values were 21.84±2.04 and 22.44±2.12 cm, respectively. The length-weight relationships were W=0.0110TL3.057 for males, W=0.0114TL3.043 for females, and W=0.0089TL3.122 for all the specimens. The results denoted a high correlation (r²=0.966; p<0.001) in the length-length relationships. Furthermore, 287 individuals (105 females and 182 males) were examined for length-girth relationships and biometric analyses. Ten morphometric characters were analyzed to analyze biometry. In conclusion, no statistically significant differences were determined in morphology between the sexes (p<0.05).
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    Evaluation of earthworm meal (Eudrilus eugeniae) as fish meal replacement in juvenile Mangrove Crab (Scylla serrata) diet
    ( 2024) Genodepa, Melanie P. ; Apines-Amar, Mary Jane S.
    Two feeding trials were conducted to evaluate the performance of the earthworm (Eudrilus eugeniae) meal (vermimeal) as a replacement for fish meal in the diet of juvenile mangrove crab (Scylla serrata) in terms of growth, feed efficiency, intermolt duration, carapace width increment, molting success, survival, and incidence of cannibalism. Four experimental diets were formulated with 0, 25, 50, and 75% fish meal protein replaced with earthworm meal protein, designated as D0, D25, D50, and D75, respectively. In the first feeding trial, the experimental diets were fed to crablets with an initial average weight of 0.09±0.007g. Each replicate comprised ten (10) crablets individually stocked in 750ml-capacity plastic containers randomly distributed in a static water bath. Final weight gain, feed efficiency and survival were measured after the 5^th^ molt. In the second feeding trial, 150 crablets with an average weight of 0.07±0.002g were stocked at 30 crablets each in five (5) replicate tanks. Survival and incidence of cannibalism were monitored daily until the end of the culture period of 30 days. The first study showed that the growth of mangrove crab juveniles fed the diet with up to 50% of the fish meal protein replaced by the earthworm meal protein was statistically comparable to the control group. The survival of crablets in the second feeding trial was highest in D25 (33%), followed by D50 (29%), D0 (18%), and lowest in the group fed with D75 (13%). Overall, earthworm meal (Eudrilus eugeniae) can replace as much as 50% of the fish meal protein in juvenile mangrove crab (Scylla serrata) diet without negative effects on growth, carapace width increment, feed efficiency, intermolt duration, molting success, survival, and cannibalism.
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    Establishing a fish repository at Ege University Faculty of Fisheries (1965-2023): A Journey on a long and challenging road to becoming a museum
    ( 2024) Bayhan, Bahar ; Akalın, Sencer ; Akçınar, Salim C. ; Taylan, Burcu ; Kaya, Murat ; Taşkavak, Ertan ; Özaydın, Okan ; Sever, Tuncay M. ; Salman, Alp ; Gürkan, Şule ; İlhan, Dilek ; Uygun, Orçin ; Altay, Burak
    This study examined preserved marine fish specimens collected from numerous field surveys conducted along Türkiye's Black Sea, Marmara, Aegean, and Mediterranean coasts since 1965. Our review and categorization of these materials revealed that the specimens belong to 360 species from 131 families. Current data shows that the museum collection includes 20 species of cartilaginous fish and 8 species of bony fish listed as endangered on the IUCN Red List, alongside 54 non-native fish species. Prepared according to museum standards by Ege University Fisheries Faculty's Scientific Material (ESFM), this collection of Turkish marine fish constitutes 66% of all Turkish marine fish fauna. This makes it the largest and oldest marine fish collection in Türkiye. Considering Türkiye's maritime borders with neighboring countries, this collection is significant nationally and globally. Given the diverse marine fish species in Turkish seas over the past half-century, this preserved material is a vital reference for local and foreign ichthyologists. If organized and transformed into a visitable museum, this extensive collection could raise awareness about the diversity of marine fish species in our seas. As a result, we have established the " biological repository of Turkish Marine Fish Department" in the Faculty Museum, now known as the Fisheries Faculty's Scientific Material (ESFM) at Ege University. We present the fish in the collection as a species list.
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    Threatened fishes of the world: Schizothorax (Racoma) biddulphi (Günther, 1876) (Cyprinidae)
    ( 2024) Wang, C.X. ; Serekbol, Gulden ; Hu, L.H. ; Yang, L.T. ; Huo, B. ; Song, Y. ; Chen, S.A
    In order to study the individual biology of endemic fish in China, lay a foundation for the conservation of its germplasm resources, and consolidate the basic biological data of endemic fish in the world. According to the ethical code and fishing permit, 21 samples of Schizothorax (Racoma) biddulphi (Günther, 1876) were collected from the Muzati River in Tarim River system from 2021 to 2022, and their morphological characteristics, age identification and anatomical observation were analyzed by classical biological methods. S. biddulphi has a long body, a conical head, a pointed snout and a lower mouth. Requires 2 pairs. The scales are small and neatly arranged; Bare or scaly chest; The lateral line scale is slightly larger. The lateral line is complete. The correlation equation between body length and body weight is: W = 4.148 × 10-5L2.791. There were 5 kinds of age identification materials: 15+ for lapillus and asteriscus, 14+ for vertebra, 11+ for opercular bone, and 9+ for anal scale. The peritoneal wall of S. biddulphi is black; The tooth type is 2·3·5-5·3·2; The gill harrow was 11\~13 for laymen and 15\~18 for experts. Diphysocyte; Gallbladder oval; The number of vertebrae is 4+42-43+1, and the number of ribs is 23 or 24. S. biddulphi is a special species in the Tarim River system, and its evolutionary adaptation is closely related to the uplift of the Qinghai-Tibet Plateau.