Carp Farming Research Articles

Penerapan Media Bioflok Dalam Budidaya Ikan Lele Dumbo Dan Ikan Gurame Di Desa Kejuden Kecamatan Depok Kabupaten Cirebon

Fish farming is an effort to utilize the resources around to achieve a common goal in a group, This activity is carried out in order to produce fish in a controlled and profit-oriented container or media. It is hoped that the products produced will be multiplied and abundant. After field observations in Kejuden Village, there is some information that the problems faced by fish farmers due to limited resources such as land and water are the main obstacles in dumbo catfish cultivation and carp farming, especially in areas with high population density such as Kejuden Village. One of them is the use of biofloc media. In this study, the researcher used a case study research method. is a research procedure that produces descriptive data obtained from informants in the field, The data collection techniques used are interviews, and observations. Based on the results of research in the field, biofloc fish cultivation techniques have been applied such as feeding, probiotic administration and fish pond maintenance, but there are several techniques that are not applied such as water quality measurement, temperature, fish growth monitoring and weight monitoring per fish. Based on the results of the study, the researcher concluded that there are several stages in the cultivation process, namely the preparation stage, both land preparation, broodstock, spawning, and other facilities that support the catfish cultivation process. The land preparation in question is the preparation of a pond for catfish cultivation. There are various types of mini kola such as earthen ponds, tarpaulin ponds, and cast ponds, or even by using other media that have currently been developed so that the process of cultivating catfish using biofloc requires a lot of great preparation.

Stocking Hatchery-Produced Mola (<i>Amblypharyngodon mola</i>) Seed in Carp Polyculture Ponds: A Performance Assessment in Odisha, India

Small indigenous fish species (SIS) such as mola (Amblypharyngodon mola) regarded as natural ‘superfoods,’ due to their high nutrient content, offer a promising avenue for addressing the nutritional deficiencies in India. Over the past decade, integrating mola into conventional carp polyculture systems has emerged as a promising nutrition-sensitive innovation, significantly enhancing micronutrient intake, particularly for women and children. However, the lack of hatchery-reared mola seed has hindered the sustainability of this approach. Recently, this bottleneck was addressed by developing a hatchery-based mass seed production protocol for mola, which was introduced into carp farming systems on a pilot basis. This study evaluates the performance of hatchery-produced mola seed inhomestead carp polyculture ponds in Odisha, India by using a field survey. Of the surveyed farmers, 24% purchased mola spawn, while 76% opted for mola fry. The average pond size of surveyed farmers was 0.32 ha with an average culture duration of 9months. Farmers stocked mola spawn at an average density of 283,583/ha and fry at 22,190/ha. Results showed that 93% of farmers achieved successful mola production, with an average mola yield of 194 kg/ha and total production of 2831 kg/ha. Molacontributed an average of 9% to the total fish production reaching a maximum contribution of up to 26%. The mola fish contributed significantly to the household in terms of additional revenue. Household consumption averaged 14 kg of mola per year, with a per capita consumption of 3 kg. Increasing pond size and optimizing stocking density emerge as critical factors positively impacting mola production and income. Overall, this study demonstrates the potential of hatchery-produced mola seed in promoting nutrition-sensitive aquacul-ture in Odisha, offering valuable insights for its scaling up.

Effect of Rice–Carp Coculture on Phytoplankton and Microzooplankton Community Composition in Paddy Water during Different Rice Growth Stages

Integrated rice–fish farming, an agricultural practice that combines cultivating rice and breeding fish in the same field, has attracted widespread attention. However, there is limited research on how the rice–carp coculture impacts the community structure of phytoplankton and microzooplankton in paddy water. This study employed eDNA metabarcoding sequencing to analyze the composition of phytoplankton and microzooplankton in a rice monoculture system (RM) and a rice–carp coculture system (RF). Following annotation, we identified 9 phyla, 89 families, 275 genera, and 249 species of phytoplankton, along with 20 phyla (or subphyla and classes), 85 families, 222 genera, and 179 species of microzooplankton. The alpha diversity indices revealed significantly higher richness, diversity, and evenness in the RF group compared to the RM group during grain-filling stage. Principal coordinates analysis (PCoA) demonstrated notable differences in the phytoplankton and microzooplankton compositions between the two groups across various rice growth stages. Composition analysis showed that rice–carp coculture increased the relative abundance of dominant phytoplankton phyla such as Bacillariophyta, Chrysophyta, and Euglenophyta while decreasing that of Cryptophyta. In microzooplankton, the coculture resulted in an increased abundance of Intramacronucleata (subphylum) and a decrease in Conoidasida (class). In conclusion, the rice–carp coculture enhances the diversity of plankton, particularly during the grain-filling stage, and simultaneously alters the composition and abundance of dominant plankton species in the paddy water. These findings enhance understanding of the broader impacts of integrated rice–carp farming on agricultural ecosystems, emphasizing alterations in the diversity and composition of aquatic microorganisms

Large-scale serial replacement of invasive tench (Tinca tinca) by invasive carp (Cyprinus carpio) in the presence of redfin perch (Perca fluviatilis) in the Murray-Darling River system, Australia

Ecosystems worldwide are increasingly being invaded by multiple species, and the rate of biological invasion is accelerating, leading to more interactions among invasive species. One such interaction that has received little attention is the phenomenon of ‘serial replacement’ or ‘over-invasion’, where an established invasive species is supplanted by a second invasive species. Understanding this interaction is important as controlling the second species could inadvertently lead to an increase in the abundance of the first species. We used a hierarchical state-space model to analyse changes in annual abundances (commercial catch-per-unit-effort) of three invasive fish species, tench (Tinca tinca), common carp (Cyprinus carpio) and redfin perch (Perca fluviatilis), in the Murray-Darling River system (MDRS), Australia between 1954–2002. Tench were present at low abundances until the mid-1970 s, before declining to the point of no commercial catch post-1989. This rapid decline coincided with a significant increase in carp abundance, suggesting that carp may have driven the tench decline through habitat modification (particularly the destruction of aquatic plants), consistent with findings from European studies that show the disappearance of tench from ponds with intensive carp farming. Redfin perch populations, were inferred to be much less impacted by the invading carp population. While carp were present in the MDRS for the duration of the study, the rapid increase in carp abundance in the early 1970 s coincided with the introduction of a specific genetic lineage—the “Boolarra strain”. Our analysis provides compelling evidence of serial replacement of long-established tench by invading common carp triggered by the introduction of a novel carp strain.

Integrated Rice–Fish Culture Alters the Bacterioplankton Community and Its Assembly Processes

The rice–fish co-culture is an important model of carp farming in China; however, research on the dynamics and assembly of water bacterial communities in this system remains limited. Therefore, this study aimed to explore the dynamics and assembly of bacterial communities, as well as their correlation with environmental factors in paddy water. For these purposes, this study was divided into two groups: a rice–carp co-culture (WRC) group and a rice monoculture (WRM) group, with 20 rice fields in each group. After 60 days of farming, the concentrations of NH4+-N, NO2−-N, TN, and PO43− were significantly higher in the WRC group than those in the WRM group. Alpha diversity analysis showed that the Shannon index in the WRC group was significantly decreased compared with the WRM group. At the phylum level, the relative abundance of Actinobacteria significantly increased, while the relative abundance of Proteobacteria and Bacteroidetes significantly decreased in the paddy water of the WRC group. The neutral community model (NCM) indicated that a random process played a dominant role in the construction of bacterial communities in the two groups, and common carp cultivation increased migration rates, thereby affecting community assembly. The co-occurrence network displayed that common carp cultivation led to looser interactions between bacterial communities. In addition, the contents of nutrients significantly affected the abundance of bacteria in paddy water. In summary, carp cultivation decreased the diversity of bacteria and changed the relative abundance of dominant bacteria, thereby affecting the stability and assembly of bacterial communities.

Goldfish Breeding Business Development in Kampung Wouma, Wamena Kota District

The potential for natural resources in the Wamena City District area is very abundant. One of the businesses being developed by the community there is goldfish farming which has been started since 2015. The aim of this study for analyze how the carp business is developing in Wouma village, Wamena city district. Method​ Qualitative is used to explain the development of the carp farming business including the condition of the breeder, the problems faced by the breeder including business capital, labor, production, price and other factors that must be considered for development. business​ fish​ m a s. Meanwhile, the analysis method quantitative used for count level farmer's net income with profit calculation. The amount of goldfish breeder capital varies, depending on the condition of the breeder. The average capital used to start a goldfish farming business ranges between Rp. 8,500,000 to Rp. 10,000,000. Of the 10 respondents studied, the number of workers needed to develop goldfish was 34 people. Generally, these breeders are heads of families with junior high school and senior high school education. Good price conditions will provide benefits for goldfish production and have a positive influence on breeders to increase their production, because prices directly affect income levels. Until 2021, the price of carp will reach Rp. 35,000 per kg, in 2022 the price of goldfish will reach IDR. 38,000 per kg and in 2023 the price of goldfish will reach IDR. 40,000 per kg. Furthermore, the goldfish production produced by breeders has increased from year to year. Carp production will range from 1,040 kg to 1,760 kg until 2023. Research shows goldfish sales don't meet consumer demand, with respondent 5 earning the least and respondent 3 earning the most.

Infeksi Ektoparasit dan Korelasinya dengan Panjang, Berat, dan Faktor Kondisi Benih Ikan Mas Merah Najawa (Cyprinus carpio Linneaus)

One of the problems in commona carp farming activities is ectoparasite infection which is thought to correlate with length, weight and condition of the fish. The aims of the research were to determine the species, prevalence, intensity and dominance of ectoparasites and to determine the correlation between the number of ectoparasites and the length, weight and condition factors of Najawa red carp (Cyprinus carpio Linneaus) fingerling at BPTPB Cangkringan. The research used laboratory observation method on randomly selected fish samples. Sampling was carried out for 3 weeks and a total of 27 individuals were examined. Ectoparasite observations were carried out on mucus samples from the body surface and gill sheets microscopically. The length and weight of each fish sample were measured and the results were used to calculate the condition factor. The correlation relationship was calculated between the number of ectoparasites and the length, weight and condition factors of the fish. The research results showed that five ectoparasites were found to infect fish samples with varying prevalence and intensity values, namely Trichodina sp., Dactylogyrus sp., Gyrodactylus sp., Glochidium sp. and Vorticella sp. Trichodina sp. has the highest prevalence, intensity and dominance compared to other parasites. The number of ectoparasites has a positive correlation with the length and weight of fish in the low category. In addition, a low negative correlation was found between the number of ectoparasites and fish condition factor. The results of this study indicate that ectoparasites are a factor that can influence the productivity of Najawa red carp cultivation.

Factors Influencing Disease Dynamics in Small-Scale Carp Polyculture in Bangladesh.

Small-scale carp polyculture plays a key role in food supply in Bangladesh. However, factors including water pollution, limited infrastructure, and inadequate disease management hinder its sustainability. This paper reports on a survey of 231 farmers across the six major carp producing regions in Bangladesh, analyzing factors including farmers' social aspects, farm characteristics, information on disease and approaches adopted to combat them, and biosecurity practices. Almost half (46.8%) of the farms surveyed experienced disease in carp species, with clear regional variations. Eighty-four percent of farms reported carp mortalities during disease outbreaks, with an average mortality level of 10.23 ± 11.81%. Clinical signs during outbreaks lasted between a week and a month, with a peak in disease outbreaks occurring in two seasonal periods between June and July and October and December. Disease incidence was related to a range of factors including the farmer's experience, ponds/farm type, stocked species, and biosecurity practice. A combination of disinfecting measures during pond preparation and measures during stocking, including discarding fingerling transport water away from the farm, fingerling disinfection, and checking the health of fingerlings before stocking, significantly reduced disease occurrence. Treatments involving antibiotics, ciprofloxacin, erythromycin, and azithromycin were reported as ineffective, raising concerns about their non-prudent use, inadequate dosing (perhaps without appropriate veterinary guidance), and the potential for driving antimicrobial resistance in the environment. The research unveils a concerning pattern of high disease incidence across small-scale carp farms in Bangladesh, and the significant potential for disease spread highlights the need for responsible disposal practices. The study emphasizes the need for improving training and awareness programs for addressing biosecurity and disease management challenges, ensuring sustainable aquaculture and community well-being.

Assessing tropism and genetic traits of carp oedema virus isolates to enhance detection strategies.

Carp oedema virus (CEV) is a relatively understudied poxvirus. It exhibits an affinity for gill and skin epithelial cells. Investigations were conducted into selected aspects of CEV biology, with a focus on determining cell and tissue tropism of CEV, acquiring gene sequences and updating CEV tests in fish tissues. A total of 238 common carp tissue samples from nine aquaculture farms were analysed. The study evaluated the efficacy of intermediate detection of CEV by real-time PCR and in situ hybridisation. The genes encoding protein P4a were sequenced, analysed and aligned in a phylogenetic tree using a molecular evolution model. In situ hybridisation revealed the necessity to validate the Centre for Environment, Fisheries and Aquaculture Science protocols for sampling for CEV detection and to use the tissues for which the virus has the highest tropism, namely the skin and kidneys, rather than solely the gills. The level of genetic variability was determined, and it was shown that CEV mutates systematically. The creation of two distinct phylogenetic clades confirms certain strains' description as Polish isolates. Determining the localisation of CEV genetic material in organs and tissues is pivotal for shaping the World Organisation for Animal Health guidelines. The utility of molecular diagnostics has been demonstrated in the skin and kidney of carp, in addition to the gills, impelling their inclusion in diagnostic protocols. The clusters identified in the phylogenetic tree offer valuable insights for developing the current PCR primers. The prevalence of CEV infection in aquaculture, juxtaposed with its notably lower detection in wild fish, underscores the significance of mandatory molecular diagnostic testing for CEV in carp farming.

Transcriptomic Responses to Koi Herpesvirus in Isolated Blood Leukocytes from Infected Common Carp.

Koi herpesvirus (KHV, CyHV-3) causes severe economic losses in carp farms. Its eradication is challenging due to the establishment of latency in blood leukocytes and other tissues. To understand the molecular mechanisms leading to KHV infection in leukocytes, common carp were bath-exposed to KHV at 17 °C. After confirming the presence of viral transcripts in blood leukocytes at ten days post infection, RNA-Seq was performed on peripheral blood leukocytes on the Illumina NovaSeq. KHV infection triggered a robust immune response mediated by pattern recognition receptors, mainly toll-like receptors (tlr2, tlr5, tlr7, and tlr13), urokinase plasminogen activator surface receptor-like, galectin proteins, and lipid mediators such as leukotriene B4 receptor 1. Enriched pathways showed increased mitochondria oxidative phosphorylation and the activation of signalling pathways such as mitogen-activated protein kinases (MAPKs) and vascular endothelial growth factor (VEGF). KHV-infected leukocytes showed low production of reactive oxygen species (ROS) and glutathione metabolism, high iron export and phagocytosis activity, and low autophagy. Macrophage polarization was deduced from the up-regulation of genes such as arginase non-hepatic 1-like, macrophage mannose receptor-1, crem, il-10, and il-13 receptors, while markers for cytotoxic T cells were observed to be down-regulated. Further work is required to characterise these leukocyte subsets and the molecular events leading to KHV latency in blood leukocytes.

First detection of Koi herpesvirus disease (KHVD) in Garmian, Kurdistan region of Iraq: A clinical and molecular study.

Koi herpesvirus disease (KHVD) is attributed to cyprinid herpesvirus-3 (CyHV-3) and predominantly affects common carp and ornamental koi carp (Cyprinus carpio). This viral infection leads to substantial morbidity and mortality among these fish species. This study aimed to confirm the presence of KHVD in the Kurdistan region of Iraq by employing clinical and optimized molecular assays on fish populations experiencing high mortality among common carp in carp farms. The present research was conducted in the Kalar district, situated at the heart of Garmian province in Iraqi Kurdistan. four samples from common carp fish farms were received by our laboratory. These samples specifically displaying clinical signs associated with koi herpesvirus (KHV) infection, were subjected to clinical examinations, and PCR assay in addition to sequence analysis. The results of the current study revealed that the observed clinical signs, particularly gill necrosis, skin lesions, and sunken eyes, closely resembled the clinical signs of KHVD in common carp fish. In addition, PCR, nested PCR, and sequence analysis assay detected appropriate DNA fragments of the CyHV-3 major capsid protein gene confirming the first detection of KHVD in common carp fish in the Kurdistan region of Iraq. In this study, the results confirm the detection of KHVD in the Kurdistan region, Iraq, for the first time. This study revealed that CyHV-3 was responsible for KHVD-related signs and symptoms. Based on these results, it is strongly recommended that comprehensive studies be initiated to investigate the prevalence and distribution of CyHV-3.

Effects of sage (Salvia officinalis) essential oil on growth, health and antioxidant capacity of common carp (Cyprinus carpio).

In the study, effects of S. officinalis essential oil on growth performance, health and antioxidant activity in C. carpio were investigated. The fish (13 ± 0.21g) were fed with diet containing 1 and 3 ml kg- 1 of sage oil for 60 days. At the end of study, growth performance was not affected in fish fed with sage essential oil (p > 0.05). Superoxide dismutase (SOD) activity in hepatopancreas increased with addition of 1ml kg- 1 sage oil to the diet. However, Catalase (CAT) activity and malondialdehyde (MDA) values were not significantly altered in common carp. Total protein, albumin, glucose and hepatopancreas enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP)) in blood serum were not affected by sage essential oil supplementation. At the histological examinations, no pathological findings were observed in hepatopancreas and intestine of carp. Goblet cells number and villi length in intestine increased with sage supplementation (p < 0.001). In addition, fertility, granulation and number of follicles increased in common carp fed with sage essential oil. Mortality after challenged with A. hydrophila was not observed in carp fed with 1ml kg- 1 concentration of sage essential oil. As a result, use of sage oil can be recommended in carp farming to improve gut health, provide disease resistance against A. hydrophila infection, and increase of fertility.

Teknis Pengelolaan Pembenihan Ikan Mas Mantap Cyprinus carpio untuk Mendapatkan Benih Kualitas Unggul

The development of mirror carp (Cyprinus carpio) farming in Indonesia has progressed very rapidly, as can be seen by the increasing number of varieties of mirror carp produced from various regions with their respective specifications and advantages. Along with the need for carp that are more resistant to environmental changes and disease attacks, the development of the Majalaya carp variety subsequently produces Mantap carp fish that are disease-resistant, and growth in the growth segment is faster. The aim of this study was to disseminate technical information on Mantap fish carp culture to the public so that it can be used as a reference source for the community, especially for cultivators who are interested in developing this fish. In this study, primary and secondary data were collected. Based on the results of a fecundity study, one female broodstock produced 104.496 kg broodstock-1, the average percentage of egg fertilization (FR) was 89,64%, the average hatching rate (HR) was 61,37%, and the average survival rate (SR) until the size of the seed size 2-3 cm reaches 60%.

Enacted relations and the resilience of territorially embedded production systems in Europe

Globalization of food chains and scale increases in business models are dramatically affecting rural areas in Europe, by a simplification of land use, new urban-rural relations and reshaped social networks. While pressures on land use systems have been increasing due to the competition on commodity markets, the role of territorially embedded production systems remains crucial in keeping farm biodiversity and unique cultural landscapes, as well as social and cultural ties. Building on the social-ecological resilience approach (Darnhofer (2020b), this paper examines the resilience of territorially embedded production systems in different regions of Europe, including emergent and ongoing patterns of material, social and cultural relations. It shows how primary producers improve the resilience of their production systems in response to increasing pressures resulting from changing ecological, economic, social and cultural conditions. Three production systems are examined: carp farming in Middle Franconia, Germany; wine production in Tuscany, Italy; and olive oil production in Alentejo, Portugal. The paper adopts an adapted relational approach to conceptualise how resilience develops in terms of the ability of producers and their networks to develop new markets, reduce costs and add value. Different types of enacted relations (sets of mutually empowering connections in space and time) are identified, including relations among family members, between farmers, along the commodity chain and with other stakeholders, such as tourism, policy and regional administrations. Using these insights, the paper argues that it is important to shift the focus of agricultural resilience from the producer level to the network level, particularly how network dynamics emerge as relations enacted by diverse actors. These collaborative efforts have the potential to enable primary producers to maintain cultural landscapes, preserve their ecosystems and ensure the farms’ economic survival and by extension help to maintain the socio-ecological resilience of territorial production systems.

Molecular Cloning, Tissue Distribution, and Pharmacological Characterization of GPR84 in Grass Carp (Ctenopharyngodon Idella).

The G-protein-coupled receptor GPR84, activated by medium-chain fatty acids, primarily expressed in macrophages and microglia, is involved in inflammatory responses and retinal development in mammals and amphibians. However, our understanding of its structure, function, tissue expression, and signaling pathways in fish is limited. In this study, we cloned and characterized the coding sequence of GPR84 (ciGPR84) in grass carp. A phylogenetic analysis revealed its close relationship with bony fishes. High expression levels of GPR84 were observed in the liver and spleen. The transfection of HEK293T cells with ciGPR84 demonstrated its responsiveness to medium-chain fatty acids and diindolylmethane (DIM). Capric acid, undecanoic acid, and lauric acid activated ERK and inhibited cAMP signaling. Lauric acid showed the highest efficiency in activating the ERK pathway, while capric acid was the most effective in inhibiting cAMP signaling. Notably, DIM did not activate GPR84 in grass carp, unlike in mammals. These findings provide valuable insights for mitigating chronic inflammation in grass carp farming and warrant further exploration of the role of medium-chain fatty acids in inflammation regulation in this species.

Prevalence of Cyprinid herpesvirus 3 and ORF150 genomic variations in carp populations of Indonesia

Cyprinid herpesvirus-3 (CyHV-3) is the etiological agent of koi herpesvirus disease (KHVD) in common and koi carp farming. This highly contagious pathogen has a 295-kb genome that harbours 156 open reading frames. Recent in vitro experimental evolution studies highlighted strong dynamics of genomic structural variations (SVs), in particular in the region of ORF150, an ORF potentially involved in virus multiplication and host inflammatory response. Among these SVs, a 1363-bp deletion could be associated with a loss of virulence. The present study aimed at investigating the genomic variations in the ORF150 region, and especially the deletion, in viruses isolated from carp populations of Indonesia. A screening of 236 fish from 43 different farms revealed a high prevalence of CyHV-3 (nearly 70%), both in symptomatic and asymptomatic common carp. However, in contrast with the results obtained in vitro, long read sequencing of the ORF150 region revealed a low level of genetic variations and the absence of the 1363-pb deletion. The complex interactions between the virus, the environment and the host, particularly the immune system, probably play an important role in this reduced variability.

End-of-season supplementary feeding in European carp ponds with appropriate plant protein and carbohydrate combinations to ecologically boost productivity: Lupine, rapeseed and, triticale

The present study investigated end-of-season (July–September) supplementary feeding strategies for European fishponds (carp farming), which suffer from collapsed natural food base (protein availability). Treatment ponds receiving white lupine (Lupinus albus), resulted in higher polyunsaturated fatty acids (PUFA) content (276.1 mg n − 3 PUFA 100 g−1) in skinless fillet of Cyprinus carpio than control ponds receiving triticale (179.5 mg n − 3 PUFA 100 g−1). Despite lupine being richer in nitrogen (N) and phosphorus (P) than triticale, eutrophication was likely suppressed in treatment ponds. Treatment ponds (∼120 g acid detergent fiber, ADF kg−1 lupine) had higher water transparency and lower water column P than control ponds (∼31 g ADF kg−1 triticale). Surprisingly, triticale (8.5% digestible protein; low DIAASLYS 36%) resulted in similar yield (∼1 ton ha−1) as lupine (26.5% digestible protein; higher DIAASLYS 52%, but low DIAASMET 32%). Therefore, protein quality (methionine) deficiency in lupine was investigated. It was balanced iso‑nitrogenously (38% crude protein) with rapeseed expeller meal (Brassica napus): diets T1 (only lupine; Met 0.9% of protein) → T2 (75% lupine: 25% rapeseed; Met 1.2% of protein) → diet T3 (50% lupine: 50% rapeseed; Met 1.4% of protein). A gradual improvement in yield, N and P retention values was observed from T1 to T3 but it did not exceed a low protein (16% crude protein) ‘control’ diet (only triticale; Met 1.9% of protein). Nutrient conversion to fish biomass (protein efficiency ratio and P: N retention ratio) seemed highest in ‘control’ followed by ‘T3’. This could be attributed to starch-mediated protein sparing effect or high organic matter digestibility of triticale (ADCNFE 76%; ADCOM 72%). Which is lacking in either lupine or rapeseed (ADCNFE ≤ 1%; ADCOM ≤ 34%) due to predominance of fibrous carbohydrates (non-starch polysaccharides, NSP). However, in ponds, they may still enhance the food web. In absence of starch, higher ADF influx in pond carp gut may halve absorption of n-3 PUFA from zooplankton. The study concludes end-of-season supplementary feeding with high DIAASMET, LYS protein combinations (e.g., lupine-rapeseed) and inclusion of starch sources (e.g., triticale) could achieve higher yield and nutrient efficiency in ponds. Most proteinaceous plant feedstuff are rich in NSP or ADF and may contribute to improving pond water quality or food web. Balanced supplementary feeds (e.g., 50% triticale +25% lupine +25% rapeseed expeller), that feed both fish (starch, optimum DIAASprotein) and pond (NSP, ADF) are suggested.

Comparative transcriptional analysis between virulent isolate HN1307 and avirulent isolate GD1108 of grass carp reovirus genotype II

As a widespread epidemic virus, genotype II of the grass carp reovirus poses a significant threat to the grass carp farming industry in China. Different genotype II isolates cause different degrees of virulence, although the underlying pathogenic mechanisms remain largely unknown. In this work, infections of grass carp with the virulent isolate grass carp reovirus (GCRV)-HN1307 and the avirulent isolate GCRV-GD1108 were performed to reveal a possible mutual transcriptional discrepancy. More differentially expressed genes (DEGs) were identified in the HN1307-infected group, which defined a grossly similar gene ontology (GO) pattern and different pathway landscape as the GD1108-infected group. Gene set enrichment analysis revealed that pathways related to innate immunity and metabolism were reciprocally activated and suppressed, respectively, following infection withHN1307, compared with GD1108. The trend analysis further indicated that immune-related pathways were involved in one of the four statistically significant profiles. Network analysis of transcription factor-gene interactions and protein-protein interactions on the immune-related profile suggested that among the core transcriptional factors (TFs) (UBTF, HCFC1, MAZ, MAX, and NRF1) and the hub proteins (Tlr3, Tlr7, Tlr9, Irf3, and Irf7), the latter were highly enriched in the toll-like receptor signaling pathway. Real-time quantitative PCR performed on the selected mRNAs validated the relative expression. This work will provide insights into the distinct transcriptional signatures from avirulent and virulent isolates of GCRV, which may contribute to the development of products for prevention.

Carp edema virus, a great threat for carp and koi farming in Henan, China

A carp disease with clinical signs of acute gill rot (AGR) has frequently occurred in Henan province of China since 2013, leading to substantial economic losses. However, the causative agent of virus-related carp AGR (CAGR) disease has been controversial. Our study showed that carp edema virus (CEV), specifically the sub-genogroup IIa, might be the primary agent causing virus-related CAGR that is endemic to Henan, China. This conclusion is based on a cohabitation experiment using isolates from an outbreak in 2019 and a retrospective analysis of CAGR samples collected between 2013 and 2015 in Henan, China. In the cohabitation experiment, the clinical development and pathological changes of CEV disease were observed. The pathological alterations in the fish brain were first noticed to be strongly associated with clinical signs of being sleepy, suggesting that pathological alterations in the fish brain may be a critical differential characteristic of CEV. Another important finding in our study was that the mortality in common carp and koi carp was strongly associated by a temperature change and less correlated to the viral loads in organs. Considering the frequent outbreaks of virus-related CAGR disease in Henan (China), effective prevention, good environmental stress management, and efficient diagnosis are needed. Based on comparing the qPCR and the nested PCR designed at the CEFAS Weymouth Laboratory, we recommend using the qPCR method on gills to identify this pathogen because of the assay's sensitivity and the viral load in gill tissues.

THE EFFICIENCY OF CARP GROWING IN FLOATING CAGES THROUGH RARING AND LOTTING

Cypriniculture is the growth of cyprinids in a controlled environment. By planning and rationalizing feed and creating appropriate conditions to cover the needs of carp farming, this branch of aquaculture is made more efficient. Carp is a poikilothermic animal that does not consume energy to maintain body temperature. Thus, the administered food is converted into body mass more effectively than in other animal species. The feed conversion ratio shall not exceed 2. The action of lotion is differentiated from the one of raring by the process of populating the floating cages according to the weight category in which the carp individuals fall. The study involves the identification of an effective method of growing carps in floating cages, depending on the weight and amount of food administered. The technique of separating carp by lotting was proven to be more efficient compared to decreasing the number of individuals on floating cage. Carp individuals remained in the same weight category without large differences between them. This ensures the uniformity of biological material, and an economic beneficial effect.