Bighead Carp Research Articles

Effects of Cathepsins on Gel Strength and Water-Holding Capacity of Myofibrillar Protein Gels from Bighead Carp (Aristichthys nobilis) under a Hydroxyl Radical-Generation Oxidizing System.

This study investigates the effects of cathepsins on the gel strength and water-holding capacity (WHC) of myofibrillar protein gels from bighead carp (Aristichthys nobilis) under a hydroxyl radical-generation oxidizing system. The myofibrillar proteins were divided into control group (with cathepsins) and E64 group (without cathepsins). The changes of cathepsin B and cathepsin L activities, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), protein oxidation (total sulfhydryl and carbonyl contents), and chemical interactions (nonspecific association, ionic bonds, hydrogen bonds, hydrophobic interactions, and disulfides) of myofibrillar protein and gels, as well as the gel strength and WHC of two groups under 0–100 mM H2O2, were measured. The results indicated that mild oxidation (10 mM H2O2) made a better gel strength and WHC. Cathepsin B and L activities decreased with increasing H2O2 concentrations but their effects on myofibrillar protein degradation still existed during 0.1–50 mM H2O2, which was expressed by higher carbonyl contents and ionic bonds at 0.1 and 50 mM H2O2, higher total sulfhydryl contents at 0 mM H2O2, and a lower intensity of MHC and actin of the control group than the E64 group. Besides more protein degradation, cathepsin proteolysis also resulted in lower gel strength and WHC in control gels than E64 gels under mild oxidation, which could be explained by lower hydrophobic interaction and moderate disulfides bonds between gel protein molecules of control gels.

Quantifying the effects of introduced Bighead Carp (Cyprinidae; Aristichthys nobilis) stocking on dominant fish species in the Ulungur Lake, China

Quantifying the effects of introduced Bighead Carp (Cyprinidae; Aristichthys nobilis) stocking on dominant fish species in the Ulungur Lake, China

Antibiotics in fish caught from ice-sealed waters: Spatial and species variations, tissue distribution, bioaccumulation, and human health risk

Antibiotics are increasingly detected in fish caught in ice-free waters, but information on fish caught in ice-sealed waters is insufficient. The concentrations of 23 antibiotics in the gills, muscles, kidneys, livers, biles, and brains of Cyprinus carpio and Hypophthalmichthys nobilis caught during winter fish-hunting activities in Chagan Lake, Haernao Reservoir, and Shitoukoumen Reservoir were systematically studied to ascertain the variations among fish species and fishing regions, tissue distribution, and bioaccumulation, as well as the potential risk to humans via the consumption of contaminated fish. The results indicated that the individual antibiotic concentration in tissues ranged from undetectable to 35.0 ng/g ww. The total antibiotic concentration in fish muscles from Shitoukoumen Reservoir was lower than that from Chagan Lake and Haernao Reservoir, but showed no significant difference between Cyprinus carpio and Hypophthalmichthys nobilis. Chloramphenicols had a high proportion in most fish tissues ranging from 28.3% to 44.0%, and the antibiotics were mainly distributed in the livers with a total concentration of 54.8 ± 9.9 ng/g ww. The mean values of bioaccumulation factors (BAF) of antibiotics in tissues ranged from 79.4 to 1000 L/kg, with the higher values found in the fish livers. The hazard quotient and hazard index value of antibiotics in the muscles of fish from ice-sealed were less than 1, indicating a negligible risk to human health via the consumption of fish muscles. This study revealed that the total antibiotic concentration in muscles showed spatial variations but not fish species-dependence. The antibiotics mainly accumulated in the livers. In addition, the target antibiotic concentrations in the muscles of fish from ice-sealed waters met the safe for consumption criteria.

Comparison of gut microbial communities, free amino acids or fatty acids contents in the muscle of wild Aristichthys nobilis from Xinlicheng reservoir and Chagan lake

BackgroundFish is favored by consumers, while amino acids and fatty acids are the main nutrients of muscle. At present, it has been found that the gut microbial community may be involved in the regulation of host material anabolism. Juvenile and adult bighead carp (A. nobilis) from Chagan lake and Xinlicheng reservoir were selected, and divided into four groups to compare the differences of gut microbial communities, free amino acid and fatty acids in muscle.ResultsThe results showed that fish in different lakes or ages contained specific microbiota, the gut microbial structure was similar, but the microbial content was significantly different. Gut microbial abundance of juvenile fish in Chagan lake was significantly higher than that of other groups. Phylum level analysis Proteobacteria was the dominant gut bacteria of fish in both adult and juvenile fish from two separate lakes. Actinobacteria was another dominant bacterial phylum in juvenile fish in both lakes. Contents of free amino acids and fatty acids in muscle were detected, and the relationships between them and gut microbial communities were analyzed. Bighead carp grew from juvenile to adult, Actinobacteria abundance decreased (P < 0.05) and Proteobacteria increased (P < 0.05). Proteobacteria was positively correlated with the contents of Thr, Lys, Pro, Asp, Gly and Glu, Actinobacteria was negatively correlated with Met and His. Meanwhile, EPA and DHA were positively correlated with Proteobacteria, EPA and DHA were not significantly associated with Actinobacteria.ConclusionIt was speculated that the contents of free amino acids and fatty acids in muscle might be affected by the difference of gut microbiota, thus affecting the taste and nutritional quality.

Dynamic Expression and Gene Regulation of MicroRNAs During Bighead Carp (Hypophthalmichthys nobilis) Early Development.

The early development of fish is regulated through dynamic and complex mechanisms involving the regulation of various genes. Many genes are subjected to post-transcriptional regulation by microRNAs (miRNAs). In the Chinese aquaculture industry, the native species bighead carp (Hypophthalmichthys nobilis) is important. However, the genetic regulation related to the early development of bighead carp is unknown. Here, we generated developmental profiles by miRNA sequencing to study the dynamic regulation of miRNAs during bighead carp early development. This study identified 1 046 miRNAs, comprising 312 known miRNAs and 734 uncharacterized miRNAs. Changes in miRNA expression were identified in the six early development stages. An obviously increased expression trend was detected during the development process, with the main burst of activity occurring after the earliest stage (early blastula, DS1). Investigations revealed that several miRNAs were dominantly expressed during the development process, especially in the later stages (e.g., miR-10b-5p, miR-21, miR-92a-3p, miR-206-3p, and miR-430a-3p), suggesting that these miRNAs exerted important functions during embryonic development. The differentially expressed miRNAs (DEMs) and time-serial analysis (profiles) of DEMs were analyzed. A total of 372 miRNAs were identified as DEMs (fold-change >2, and false discovery rate <0.05), and three expression profiles of the DEMs were detected to have co-expression patterns (r > 0.7, and p < 0.05). The broad negative regulation of target genes by miRNAs was speculated, and many development-related biological processes and pathways were enriched for the targets of the DEMs, which might be associated with maternal genome degradation and embryogenesis processes. In conclusion, we revealed the repertoire of miRNAs that are active during early development of bighead carp. These findings will increase our understanding of the regulatory mechanisms of early development of fish.

The antioxidant activities and flavor properties of glycated bighead carp meat hydrolysates produced with galactose and galacto-oligosaccharides

Oligosaccharides widely participate in Maillard reactions during food processing, but the mechanisms leading to differences in conjugates derived from galactose (gala) and galacto-oligosaccharides (GOS) in food processing is not well understood. Herein, spectral characteristics, antioxidant activities, and flavor properties were compared between two types of conjugates. Spectral analysis (ultraviolet–visible absorption spectra and fluorescence) indicated higher reactivity in gala groups (p < 0.05). The maximum DPPH scavenging activity and reducing power observed for the gala groups were 35.1 and 274 μmol TE/g protein, respectively, which were almost twice those for GOS groups (p < 0.05). Gala groups also exhibited a stronger capacity to diminish the saltiness of BCH compared to GOS groups. Among the 66 aromatic compounds identified using HS-SPME-GC/MS, alcohols (26.0%) and hydrocarbons (52.0%) were the most abundant flavor constituents. Particularly, 2-(3-methylbutyl)-3,5-dimethyl pyrazine was the most abundant pyrazine observed in GOS groups and its abundances increased from 1.20% to 8.30% with increased ratios of saccharide:BCH, while 2,5-dimethyl-3-(3-methyl butyl)pyrazine decreased from 8.47% to 3.35% in gala groups. Overall, the results indicated that the extent of Maillard reaction progress affected the antioxidant and flavor characteristics of MRP, which provide new insights for the further applications of MRPs in food additives.

The characteristics of spatial-temporal distributions of fish resources in Lake Jingpo based on hydroacoustic assessment

2020年5、7和10月，采用多网目复合刺网调查和水声学探测相结合的方式对镜泊湖鱼类群落时空动态和资源量进行调查.渔获物调查共采集鱼类4目6科29种，其中鲤科鱼类最多，主要经济鱼类为鲢（Hypophthalmichthys molitrix）、鳙（Aristichthys nobilis）、蒙古鲌（Chanodichthys mongolicus）、瓦氏雅罗鱼（Leuciscus waleckii）、鲤（Cyprinus carpio）、翘嘴鲌（Culter alburnus）.蒙古鲌和（Hemiculter leucisculus）为优势种.水声学探测结果表明，镜泊湖鱼类密度在春季、夏季和秋季分别为836、7216和2724 ind./hm²，其中夏季鱼类密度最高且主要集中于中部和南部区域，春季和秋季鱼类密度则呈现从南至北递减的趋势.春、夏、秋季鱼类的平均目标强度为-43.4、-50.0和-46.5 dB，估算的平均全长分别为34.0、18.0和25.2 cm，推算的平均体重分别为272.7、43.7和135.2 g.结合各季节平均密度，估算出春、夏、秋季镜泊湖鱼类资源量分别为2052、2835和3313 t.镜泊湖鱼类密度与环境因子之间的冗余分析结果表明，水体总悬浮物、叶绿素a、水温和溶解氧是影响鱼类群落结构变化的关键环境因子.从水声学探测和刺网调查的结果来看，镜泊湖渔获物小型化问题突出，鱼类资源呈现衰退趋势，渔业资源的不合理利用是造成镜泊湖鱼类资源衰退的主要因素.因此建议强化对自然捕捞的管理，严格控制捕捞数量和规格，保障鱼类资源自然增殖，结合牡丹江流域污染防治、改善鱼类栖息地环境等鱼类生境修复措施，以促进鱼类资源的恢复.;In May, July and October 2020, a combination of multi-mesh gillnet and hydroacoustic survey was undertaken to investigate the characteristics of spatial-temporal distributions of fish resources of Lake Jingpo. A total of 29 fish species, belonging to four orders and six families, were collected during the survey. The main economic fish are Hypophthalmichthys molitrix, Aristichthys nobilis, Chanodichthys mongolicus, Leuciscus waleckii, Cyprinus carpio, and Culter alburnus. The dominant species are Chanodichthys mongolicus and Hemiculter leucisculus. The average fish density was 836 ind./hm² in spring, 7216 ind./hm² in summer and 2724 ind./hm² in autumn. In summer, fish mainly inhabited in the central and southern regions. In spring and autumn, the species density showed a decreasing trend from the south to the north. The average target strengths were -43.4, -50.0 and -46.5 dB in spring, summer and autumn, the estimated average total lengths 34.0, 18.0 and 25.2 cm, and the estimated average weights 272.7, 43.7 and 135.2 g, respectively. The estimated average density of fish resources in Lake Jingpo was 2052, 2835 and 3313 t in spring, summer and autumn, respectively. The results of redundancy analysis between the fish density and environmental factors in Lake Jingpo showed that the total suspended solids, chlorophyll-a, water temperature and dissolved oxygen were the key environmental factors affecting the changes of fish community structure. According to the results of hydroacoustic and gillnet survey, the problem of miniaturization of catches in Lake Jingpo is prominent, and the fish resources are declining. Irrational utilization is the main factor resulting in the decline of fishery resources in Lake Jingpo. We recommend the relevant authorities strengthen the management of natural fishing strictly control the number and size of fishing, ensure the natural proliferation of fish resources, and integrate the pollution control of the Mudanjiang River Basin and the improvement of fish habitat environment and other fish habitat restoration measures, in order to promote the recovery of fishery resources.

江西柘林水库鱼类群落结构及功能多样性分析

PDF HTML阅读 XML下载 导出引用 引用提醒 江西柘林水库鱼类群落结构及功能多样性分析 DOI: 10.5846/stxb202106031466 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划项目（2019YFD0900603）；财政部和农业农村部：国家现代农业产业技术体系资助（CARS-46）；中国水产科学研究院基本科研业务费院级湖库增殖渔业创新团队项目（2020TD57） Community structure and functional diversity of fishes in Zhelin Reservoir, Jiangxi Province Author: Affiliation: Fund Project: National Key Research and Development Program of China (No.No.2019YFD0900603); Supported by China Agriculture Research System of MOF and MARA（CARS-46）; Central Public-interest Scientific Institution Basal Research Fund，CAFS (NO.2020TD57) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了解江西柘林水库鱼类群落结构和多样性的时空变化特征，研究鱼类物种多样性和功能多样性的关系，于2020年9月至2021年4月在该水库调查分析了鱼类物种组成、优势度及群落物种多样性和功能多样性。结果表明，共采集鱼类53种，分属于5目12科36属。其中，鲤形目（38种）种类最多，占调查物种数的71.69%，柘林水库上、中、下游库区分别采集到鱼类36、40和32种，各库区均以鲤形目鱼类为主，分别占采集物种数的72.97%、85.00%和75.00%。优势物种主要是䱗（Hemiculter leucisculus）、鳙（Aristichthys nobilis）和黄尾鲴（Xenocypris davidi），重要种主要是草鱼（Ctenopharyngodon idella）、鲢（Hypophthalmichthys molitrix）、鳊（Parabramis pekinensis）、鲫（Carassius auratus）、蒙古红鲌（Erythroculter mongolicus）等。鱼类群落结构季节性差异大于空间格局差异，主要表现为秋季和冬季之间；生物多样性指数Margalef和功能丰富度指数在上游修河水域相对较高，鱼类物种多样性和功能多样性空间格局差异性大于时间尺度下的差异性。物种多样性与功能多样性的回归分析结果显示，功能丰富度与物种多样性指数之间存在显著的正相关关系；功能冗余度与各物种多样性之间呈现负相关关系，说明物种数的增加导致了库区鱼类功能丰富度的增加和功能冗余度的降低，而功能均匀度未发生明显的变化，主要原因为调查区域内拥有不同功能性状的鱼类群体之间在个体数比例上呈现不均匀分布的模式，这一结果预示着拥有较多物种的群落生态位重叠度相对较低，生态系统受干扰后的恢复能力较差。总体而言，保护鱼类生物多样性和维护生态系统的稳定性应该通过调控鱼类种群结构达到提高鱼类群落冗余度以及资源和生境可用性的目的。 Abstract:To understand the spatial and temporal variation of fish assemblage structure and biodiversity, as well the relationships between fish taxonomical diversity and functional diversity, species compositions, the dominant species, taxonomical and functional diversity of fish communities which were captured from Zhelin Reservoir from September 2020 to April 2021 were investigated and analyzed. The results showed that a total of 53 fish species belonging to 5 orders, 12 families, and 36 genera were sampled with dominant Cyprinidae accounting for 71.69% of the total species. Among the reservoir spatial scales, 36, 40 and 32 fish species which accounting for 72.97%, 85.00% and 75.00% of the total sampled species were captured from upper-, middle- and low-reach, respectively. Hemiculter leucisculus, Aristichthys Nobilis and Xenocypris davidi were dominant species, while Ctenopharyngodon idella, Hypophthalmichthys molitrix, Parabramis pekinensis, Carassius auratus and Erythroculter mongolicus were main species in Zhelin Reservoir. The analysis of PERMANOVA (Permutational Multivariate Analysis of Variance) using the fish assemblage matrixes showed that the seasonal variation of species compositions was more significant than the spatial scale, and the variations were mainly performed between two seasons of antum and summer. Meanwhile, biodiversity indexes and functional diversity indexes of fish assembalges performed relative higher variations among spatial scales than temporal scales. Margalef index were relatively higher in the Xiuhe River than those in other water sites, while the indexes of Shannon, Simpson and Peilou indexes showed no variation among the reaches. Functional richness possessed relative higher level in upper reach than midlle and lower reaches, while functional evenness and functional disperse performed non changes among spatial scales. Functional redundancy had no variation among spatial and temporal scales. Regression analyses showed significant positive relationships between the biodiversity index of functional richenss and functional disperse with each taxonomical diversity index, while there were negative relationships between functional redundancy and taxonomical diversity indexes, which implying the increase of species richness led to the increase of the functional richness and decrease of functional redundancy. However, functional evenness did not change obviously which can mainly be explained by the disproportionate individuals of different fish functional groups. The results implied that interference resulted in a lower niche overlap of fish community with high species richness and lower ecosystem recovery ability. In general, the species diversity level of Zhelin Reservoir is lower and the anti-interference ability of this ecosystem is relatively weaker. To protect fish biodiversity and maintain the stability of the ecosystem, it is necessary to improve the fish community redundancy and the availability of resources and habitats by regulating the fish population structure. 参考文献 相似文献 引证文献

Soya milk using for rearing of cyprinids larvae in Uzbekistan environments

Common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis) larvae were reared in monoculture in earthern ponds and fed with soya milk. Day before feeding, soya beanswas been soaked in water, in 9 hours they weregrinded with some water for soys milk production. For one month, 15 kg/ha of soybean was applied in each pond. In a month, silver carp reached 1.0 - 2.1 (on average 1.49) g, common carp - 1.0 - 2.5 (1.43), grass carp - 1.3 -2.7 (1.81) g, bighead carp 1.1 - 2.0 (1.61) g. Food conversion rate of soya milk was 1.6 - 9.8, fry survival rate was 41 - 45%.

Acetochlor Affects Bighead Carp (Aristichthys Nobilis) by Producing Oxidative Stress, Lowering Tissue Proteins, and Inducing Genotoxicity.

Acetochlor is persistently used in the agroproduction sector to control broadleaf weeds. Due to frequent and continuous applications, this herbicide can reach nearby water bodies and may induce deleterious changes in aquatic life. Therefore, investigation of harmful impacts of different environmental pollutants, including herbicides, is vital to knowing the mechanisms of toxicity and devising control strategies. The current experiment included bighead carp (n = 80) to estimate adverse impacts. Fish were randomly placed in 4 different experimental groups (T0-T3) and were treated for 36 days with acetochlor at 0, 300, 400, and 500 μg/L. Fresh blood without any anticoagulant was obtained and processed for nuclear and morphological changes in erythrocytes. At the same time, various visceral organs, including the gills, liver, brain, and kidneys, were removed and processed on days 12, 24, and 36 to determine oxidative stress and various antioxidant biomarkers. Comet assays revealed significantly increased DNA damage in isolated cells of the liver, kidneys, brain, and gills of treated fish. We recorded increased morphological and nuclear changes (P ≤ 0.05) in the erythrocyte of treated fish. The results on oxidative stress showed a higher quantity of oxidative biomarkers and a significantly (P ≤ 0.05) low concentration of cellular proteins in the gills, liver, brain, and kidneys of treated fish compared to unexposed fish. Our research findings concluded that acetochlor renders oxidative stress in bighead carp.

Exploring the fish assemblage structure in the process of ecological stocking: A case study of Daye Lake

As human activities cause water eutrophication and overfishing, which had a serious impact on fish resources, fish diversity showed a downward trend. In order to understand the changes of fish assemblage structure in the process of ecological stocking and effectively, the existing fish community in Daye Lake which was divided into 9 sites was evaluated in the summer of 2019 and 2020, and fish resources were investigated by traditional fishing and eDNA metabarcoding technology. The results showed that 33 species belonging to 18 genera, 6 families and 4 orders of fish were investigated in Daye Lake based on traditional fishing methods. Among them, Hypophthalmichthys molitrix and Hypophthalmichthys nobilis were the dominant species in Daye Lake all year round, and the dominant group was omnivorous, middle-lower fish. And the fish communities at the same point at different times were similar, the separation degree of fish communities was relatively high among different locations. Based on eDNA metabarcoding technology, the mitochondrial COI (cytochrome oxidase I) and 12S rRNA gene regions of eDNA were amplified respectively. A total of 10 species of freshwater lake fish were detected, of which 7 were detected together with traditional methods. Alpha and Beta diversity analysis showed that GJQ had the lowest species diversity, DW and LJH had the highest species diversity, and the biodiversity of adjacent sites was relatively similar. This study proved that ecological stocking will not have a great impact on the diversity of fish populations in lakes. At the same time, it proved the effectiveness of eDNA metabarcoding technology in fish diversity investigation.

Impact of alien fishes on the distribution pattern of indigenous freshwater fishes of Punjab, Pakistan.

Pakistan is the country with mega freshwater fish diversity of native and alien species. In the presence of enormous native fishes varies species of exotic fishes have been introduced into the freshwater bodies of Pakistan which are competing with native freshwater fish fauna and making them deprive of food and habitat as well. Intentional or accidental introductions of animals, plants and pathogens away from their native niche is considered as major leading problem for biodiversity of invaded habitat. Three years study (from January 2017 to December 2019) was conducted in freshwater bodies of Province Punjab, Pakistan. Study was designed to know exotic species impacts on the distribution of native species of fishes. During current survey a total of 68 (indigenous and exotic) fish species belonging to 14 families were recorded from head Qadirabad, head Baloki, Islam headworks and Rasul barrage. Statistical analysis showed that Shannon-Wiener diversity index was the highest (1.41) at both Rasul barrage and Islam headworks but, invasive species were present in very less number in these study sites i.e. Oreochromis mozambicus, O. niloticus, Hypophthalmichthys nobilis, Carassius auratus, Ctenophryngdon idella, Cyprinus carpio and H. molitrix. The diversity index showed that comparatively low diversity was present in both area head Qadirabad (1.30) and head Baloki (1.4) due to high pressure of invasive species. Direct observation of species and statistical analysis showed that aliens' species produced negative impact on the local fish fauna diversity, evenness, and numbers. It is concluded that many factors are impacts on the diversity of native fishes, but alien (invasive) species also play a major role to reduction of native species, because aliens' species produce competition for native species. So it is urgent need to analysis the aliens and native food web and roosting sites in Pakistan, in future.

Aquaculture in Serbia

Serbian aquaculture is practiced in warmwater (carp) farms, coldwater (trout) farms, cage systems, recirculating aquaculture systems (RAS) and fish tanks. The total area under carp farms (ponds) registered by the Statistical Office of the Republic of Serbia (SORS) in the last fourteen years has varied between 6,192 and 8,940 ha, while under the area under trout farms was between 33,255 m2 and 81,411 m2. Total fish production over the last fourteen years varied between 5,070 tons, recorded in 2017 and 8,195 tons of market fish, recorded in 2010. Fish production is dominated by common carp and rainbow trout (about 90% of total production). In addition to these two species, several other species are cultured at carp farms, such as catfish, pikeperch, pike, silver carp, bighead carp, grass carp, Prussian carp and tench. In trout farms, additional cultured species are usually brook trout, huchen and grayling, while cultured fish species in RAS systems are sterlet and Russian sturgeon.

Emerging control strategies for integrated pest management of invasive carps

Invasive carps are ecologically and economically problematic fish species in many large river basins in the United States and pose a threat to aquatic ecosystems throughout much of North America. Four species of invasive carps: black carp (Mylopharyngodon piceus), grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis), are particularly concerning for native ecosystems because they occupy and disrupt a variety of food and habitat niches. In response, natural resource agencies are developing integrated pest management (IPM) plans to mitigate invasive carps. Control tools are one key component within a successful IPM program and have been a focal point for development by governmental agencies and academic researchers. For example, behavioural deterrents and barriers that block migratory pathways could limit carps range expansion into new areas, while efficient removal methods could suppress established carp populations. However, control tools are sometimes limited in practice due to uncertainty with deployment, efficacy and availability. This review provides an overview of several emerging modelling approaches and control technologies that could inform and support future invasive carp IPM programs.

Fish muscle hydrolysate obtained using largemouth bass Micropterus salmoides digestive enzymes improves largemouth bass performance in its larval stages.

The present study utilized digestives tracts from adult largemouth bass (LMB) to hydrolyze Bighead carp muscle and obtain an optimal profile of muscle protein hydrolysates that would be easily assimilated within the primitive digestive tract of larval LMB. Specifically, muscle protein source was digested for the larva using the fully developed digestive system of the same species. The objectives of this study were: 1) to develop an optimal in vitro methodology for carp muscle hydrolysis using LMB endogenous digestive enzymes, and 2) to evaluate the effect of dietary inclusion of the carp muscle protein hydrolysate on LMB growth, survival, occurrence of skeletal deformities, and whole-body free amino acid composition. The study found that the in vitro hydrolysis method using carp intact muscle and LMB digestive tracts incubated at both acid and alkaline pH (to mimic digestive process of LMB) yielded a wide range of low molecular weight fractions (peptides), as opposed to the non-hydrolyzed muscle protein or muscle treated only with acid pH or alkaline pH without enzymes from LMB digestive tracts, which were comprised of large molecular weight fractions (polypeptides above 150 kDa). Overall, the dietary inclusion of the carp muscle hydrolysate improved growth performance of larval LMB in terms of final average weight, weight gain, DGC, SGR, and body length after 21 days of feeding compared to fish that received the diet based on non-hydrolyzed carp muscle. The study also found that hydrolysate-based feed significantly reduced skeletal deformities. The positive growth performance presented by fish in the hydrolysate-fed group possibly resulted from matching the specific requirements of the larvae with respect to their digestive organ development, levels of digestive enzymes present in the gut, and nutritional requirements.

Sodium chloride-induced oxidation of bighead carp (Aristichthys nobilis) fillets: The role of mitochondria and underlying mechanisms

The NaCl addition is associated closely with oxidation of meat, and mitochondria are the key regulator in oxidation process of proteins. This study was set out to find a potential mechanism of oxidation induced by different concentrations NaCl (0 M, 0.5 M, 1.0 M and 2.0 M) based on the mitochondria pathway in fish. With the increase in concentrations of NaCl, the oxidation levels in bighead carp fillets moved to a higher degree. Samples showed significant lower mitochondrial membrane potential and permeability than control after being treated with 1.0 M and 2.0 M NaCl for 3 h. The activities of succinate dehydrogenase and cytochrome-c reductase decreased significantly in 0.5 M, 1.0 M and 2.0 M NaCl-treated samples and reactive oxygen species content increased in 2.0 M NaCl-treated samples compared to 0 M group. NaCl also destroyed the structure of the mitochondrial membranes and together influenced the activities of peroxisomes. Overall, 2.0 M NaCl promotes the lipid or protein oxidation in fillets might due to its effects on structure, complexes and antioxidant enzymes activity in mitochondria.

Influence of Drying Techniques on Antioxidants and Functional Properties of Bighead Carp (Hypophthalmichthys nobilis) Fillets

Bighead carp fish (Hypophthalmichthys nobilis) under different drying processes was evaluated for heavy metals, proximate compositions with functional properties, and free radical scavenging activity to identify different nutritious components that can be applied in food industries. Protein, ash, and fat were higher under microwave drying compared with the air-drying process. Protein content was 64.89% using microwave technique, while oven drying was 64.57%. WHC value was higher under oven drying technique while the raw fish was recorded the lowest value of WHC. Antioxidant activity (DPPH) was showed a significant difference among all treated samples. Farming and breeding bighead carp in fish farms can be a good resource for protein and other nutritional components in some poor countries to reduce the nutritional gap in food products.

Proteomic analysis of exudates in thawed fillets of bighead carp (Hypophthalmichthys nobilis) to understand their role in oxidation of myofibrillar proteins

For frozen fillets, the formation of ice crystals destroys the integrity of cell and organelle membranes and causes the release of enzymes that are capable of catalyzing oxidation of myofibrillar proteins (MPs). Exudates from fresh, freeze–thaw (F-T) treated, and frozen stored fillets that were contained those enzymes were collected to explore the protein composition and changes in abundance of the main protein oxidation-related enzymes. Results indicated that enzymes with oxidative capacity were up-regulated and some antioxidant enzymes were down-regulated in exudates collected from 5 months frozen fillets. Changes in abundance of MPs in exudates suggested that degradation of MPs in thawed fillets was a comprehensive result of the F-T treatment, enzymatic degradation, and protein oxidation. The oxidative capacity of exudates was confirmed because incubation with exudates enhanced carbonyls and Schiff bases contents in MPs. Overall, the results of our study suggested that enzymes in exudates were a potential factor in protein oxidation in thawed fillets.

Induced Breeding of Freshwater Fishes and Cost Benefit Analysis of a Selected Fish Hatchery in Jashore, Bangladesh

An investigation was carried out to know the induced breeding techniques of some firewater fish species such as rui (Labeo rohita), catla (Catla catla), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella), common carp (Cyprinus carpio), bighead carp (Hypophthalmichthys nobilis), sharpunti (Puntius sarana) and bata (Labeo bata) at Ma Fatima Fish Hatchery in Chanchra, Jashore, Bangladesh. The cost-benefit analysis was also performed on this hatchery for three months from May to July, 2016. The brood fishes purchased from different local sources were used for spawning. The hatchery mainly practiced induced breeding by maintaining proper age and weight of brood stock during spawning. The ranges of fertilization and hatching rates of the experimental fishes were 80.04±1.44 % to 94.35±0.54% and 75.34±3.49% to 88.68±2.76%, respectively. Total spawn production was 960, 862 and 734 kg, and the total revenue income from spawn sell was BDT 2,883,500, 2,355,100 and 1,844,800 (BDT 85 = 1 US$) in May, June and July, respectively. Estimated capital cost was BDT 87,90,000, while the operating costs were BDT 1,810,650; 1,555,105 and 1,267,680 in May, June and July, respectively. The calculated cost-benefit ratios in May, June and July were 1.59, 1.51 and 1.46, respectively. The hatchery got the highest net profit of BDT (Bangladeshi Taka) 1,041,906 in May due to the highest production and higher price of spawn, and the lowest profit of BDT 546,176 was obtained in July. So, May was found to be the peak breeding month of Ma Fatima Hatchery. The estimated cost-benefit ratio indicated that the spawn production through induced breeding techniques was profitable for the hatchery owners.

Modeling ecosystem impacts of the invasive Japanese smelt Hypomesus nipponensis in Lake Erhai, southwestern China

Introductions or alien species invasions will induce changes in aquatic ecosystems but are rarely reported in Chinese highland lakes. The Japanese smelt (Hypomesus nipponensis) invaded and has become a dominant fish species in Lake Erhai, a highland lake in southwestern China, since 2016. Here, we engineered Ecopath models for two different periods, 2008–2009 (preinvasion) and 2016–2018 (postinvasion), in Lake Erhai to model ecosystem impacts from the Japanese smelt invasion. In the dynamic Ecosim model based on the 2016–2018 Ecopath model, we ran three 50-year scenarios to simulate the potential effects of Japanese smelts on the system. Our results showed competition between invasive and native species as well as changes in trophic structures, highlighting the impacts of the invasive species over time. The lake ecosystem additionally experienced significant degradation after invasion, mainly reflected in several related indicators, such as total biomass/total system throughput (TB/TST), total primary production/total biomass (TPP/TB), total primary production/total respiration (TPP/TR), Finn's mean path length (FML), Finn's cycling index (FCI) and the Connectance Index (CI). The simulation results indicated that the relative biomass of icefish (Neosalanx taihuensis), bighead carp (Hypophthalmichthys nobilis), sharpbelly (Hemiculter leucisculus), and zooplankton were significantly affected by increasing the strength of the top-down control of the Japanese smelt on its prey. It is also important to do ecological regulation of planktivorous fishes in the studied Lake Erhai, especially the Japanese smelt.