Transcriptome analysis reveals immune pathways underlying resistance in the common carp Cyprinus carpio against the oomycete Aphanomyces invadans

Infection with Aphanomyces invadans is a serious fish disease with major global impacts. Despite affecting over 160 fish species, some of the species like the common carp Cyprinus carpio are resistant to A. invadans infection. In the present study, we investigated the transcriptomes of head kidney of common carp experimentally infected with A. invadans. In time course analysis, 5288 genes were found to be differentially expressed (DEGs), of which 731 were involved in 21 immune pathways. The analysis of immune-related DEGs suggested that efficient processing and presentation of A. invadans antigens, enhanced phagocytosis, recognition of pathogen-associated molecular patterns, and increased recruitment of leukocytes to the sites of infection contribute to resistance of common carp against A. invadans. Herein, we provide a systematic understanding of the disease resistance mechanisms in common carp at molecular level as a valuable resource for developing disease management strategies for this devastating fish-pathogenic oomycete

A global review of problematic and pathogenic parasites of farmed tilapia

Over the past 80 years, tilapia have been translocated globally for aquaculture; active production is recorded in >124 countries. Of 7 million tonnes of tilapia produced in aquaculture, 79% is from 79 countries outside the natural range of tilapia. Capture fisheries account for a further 723,627 tonnes of tilapia, and >47% of this is landed from established invasive populations outside Africa. Tilapias host a rich fauna of parasites, many of which have been translocated with their hosts. This review summarises >2500 host–parasite records from 73+ countries and >820 recorded tilapia translocations (provided in the supplementary materials). This work focuses on the notable pathogens that threaten the health of cultured populations of tilapia, providing a description of their pathology and includes species that also have substantial impacts on wild tilapia populations, where relevant. For each major parasite taxonomic group, we highlight which parasites have been translocated or have been acquired from the new environments into which tilapia have been introduced, together with remarks on standard treatment approaches and research on them and their management and control. Regarding the theme ‘Tilapia health: quo vadis?’, Africa has enormous potential for aquaculture growth, but substantial knowledge gaps about tilapia parasites in many African states remain, which creates associated production and biosecurity risks. For each parasitic group, therefore, the risks of parasite translocation to new regions as tilapia aquaculture industries expand are highlighted

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Not AvailableThe digestive physiology of butter catfish was studied by assessing the activity of different pancreatic (trypsin, chymotrypsin, α-amylase and lipase), gastric (pepsin) and intestinal (alkaline phosphatase) enzymes from hatching until the juvenile stage (30 dph). Larvae were reared at 27 °C and fed with Artemia nauplii from 2 days post hatching (dph) until 10 dph, from 7–10 dph with Artemia nauplii and zooplankton (Cyclopoida) and from 10 dph onwards only with zooplankton. The assessment of the activity of digestive enzymes showed that enzymes involved in the digestion of proteins, lipids and carbohydrates were present in butter catfish larvae before mouth opening and increased after the onset of exogenous feeding, coinciding with the histological organization of the exocrine pancreas. The specific activity of most of the pancreatic enzymes increased until 15 dph and decreased thereafter coinciding with the increase of pepsin. A progressive shift in activity from alkaline (trypsin and chymotrypsin) to acid (pepsin) proteases indicated a change in the digestive physiology of the specimen, as alkaline proteases were no longer the main digestive enzymes involved in protein digestion after the onset of acidic digestion between 15 and 21 dph. The maturation of the intestine and the achievement of a juvenile-like mode of digestion were demonstrated by changes in enzyme activities from the exocrine pancreas and stomach that coincided with alterations in enzyme production occurring in the intestine (e.g. alkaline phosphatase). Considering the ontogenetic development of the digestive enzymes from the pancreas, stomach and intestine, butter catfish larvae might be weaned between 15 and 21 dph, as larvae have achieved the complete maturation of their digestive capacities. These results contradict previous recommendations, which were based solely on the histological organization of the gastric gland and histochemical properties of mucous cells from the stomach, to wean butter catfish larvae at earlier ages. These findings on the functional development of the digestive system in butter catfish would be useful to improve the actual larval rearing techniques for this promising catfish species from the Indian sub-continent.International Foundation for Science, Swede

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The work was carried out under“All India NetworkProject on Fish HealthInfection withAphanomyces invadansis a serious disease affecting freshwater and brackishwaterfish. Even after50 years of itsfirst occurrence, to date, there is no effective treatment for this disease. To develop an effectivetreatment against this disease, in the current study, we have evaluated the potential of six commonly usedchemicals and drugs with known antifungal properties against different life-stages (zoospore production, ger-mination of zoospores and growth of hyphae) ofA. invadans. The chemicals namely formalin, potassium per-manganate (KMnO4), hydrogen peroxide (H2O2), sodium thiosulphate (Na2S2O3) and drugs including ampho-tericin B andfluconazole were evaluated in a dose-dependent manner (0.1, 1.0, 5, 10 and 100 ppm) underinvitroconditions. Out of the chemicals tested, formalin could completely inhibit zoospore production and sig-nificantly inhibit germination of zoospores and growth of hyphae at 10 ppm, however, complete inhibition ofzoospore germination and growth of hyphae could only be observed at 100 ppm. In the case of H2O2, there wassignificant inhibition of germination of zoospores and growth of hyphae at the highest concentration of 100 ppm,but it could not completely inhibit zoospore production, germination of zoospores and growth of hyphae. KMnO4at the highest tested concentration (100 ppm), completely inhibited zoospore production and significantly in-hibited germination of zoospores and growth of hyphae. Na2S2O3was found to be ineffective against all the threelife-stages ofA. invadanseven at the highest tested concentration of 100 ppm. Out of the two antifungal drugs,fluconazole could reduce the germination of zoospores and growth of hyphae significantly at a dose of 1 ppm. Onthe other hand, in the case of amphotericin B, significant inhibition of germination of zoospores and growth ofhypahe was observed only at 100 ppm. Both drugs completely inhibited zoospore production only at 100 ppm.From thefindings of the present study, it can be inferred that out of the six compounds, formalin andfluconazolehave better anti-oomycete effects underin vitroconditions. The information generated would serve as a basis fordeveloping treatment measures against infection withA. invadansin aquaculture pondsIndian Council ofAgricultural Research is duly acknowledge

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Not AvailableA continuous cell line has been developed from thymus explants of Catla catla and the cells have been subcultured for 63 passages. The cells exhibited optimum growth at 30°C in L-15 medium containing 15% foetal bovine serum. The cultured cells engulfed yeast cells and fluorescent latex beads. These cells produced reactive oxygen and nitrogen intermediates following stimulation with lipopolysaccharide and phorbol esters. The culture supernatant from the cultured cells had lysozyme activity and these cells demonstrated Fc receptors. Almost all the cells were positive for alpha-naphthyl acetate esterase enzyme suggesting that the cells are of macrophage lineage and therefore, the cell line was designated as catla thymus macrophage (CTM) cell line. CTM cells formed aggregates around zoospores of Aphanomyces invadans, but were unable to inhibit the germination of spores. The karyotype analysis of CTM cells at 25th passage revealed a typical diploid model with 50 chromosomes per cell. Partial amplification, sequencing and alignment of fragments of two mitochondrial genes 16S rRNA and cytochrome c oxidase subunit 1 confirmed that the CTM cell line originated from C. catla. This cell line should be useful for studying the role of macrophages in differentiation and maturation of thymocytes and can be a source of macrophage-specific enzymes and cytokinesNot Availabl

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Open access peer-reviewed scientific mega journal covering research in the biological and medical sciencesBackground: Herpesviral hematopoietic necrosis disease, caused by cyprinid herpesvirus-2 (CyHV-2), is responsible for massive mortalities in the aquaculture of goldfish, Carassius auratus. Permissive cell lines for the isolation and propagation of CyHV-2 have been established from various goldfish tissues by sacrificing the fish. Here, we report the development of a cell line, FtGF (Fantail Goldfish Fin), from caudal fin of goldfish using non-lethal sampling. We also describe a simple protocol for successful establishment and characterization of a permissive cell line through explant method and continuous propagation of CyHV-2 with high viral titer using this cell line. Methods: Caudal fin tissue samples were collected from goldfish without killing the fish. Cell culture of goldfish caudal fin cells was carried out using Leibovitz's L-15 (L-15) medium containing 20% FBS and 1X concentration of antibiotic antimycotic solution, incubated at 28 °C. Cells were characterized and origin of the cells was confirmed by sequencing fragments of the 16S rRNA and COI genes. CyHV-2 was grown in the FtGF cells and passaged continuously 20 times. The infectivity of the CyHV-2 isolated using FtGF cells was confirmed by experimental infection of naïve goldfish. Results: The cell line has been passaged up to 56 times in L-15 with 10% FBS. Karyotyping of FtGF cells at 30th, 40th and 56th passage indicated that modal chromosome number was 2n = 104. Species authentication of FtGF was performed by sequencing of the 16S rRNA and COI genes. The cell line was used for continuous propagation of CyHV-2 over 20 passages with high viral titer of 107.8±0.26 TCID50/mL. Following inoculation of CyHV-2 positive tissue homogenate, FtGF cells showed cytopathic effect by 2nd day post-inoculation (dpi) and complete destruction of cells was observed by the 10th dpi. An experimental infection of naïve goldfish using supernatant from infected FtGF cells caused 100% mortality and CyHV-2 infection in the challenged fish was confirmed by the amplification of DNA polymerase gene, histopathology and transmission electron microscopy. These findings provide confirmation that the FtGF cell line is highly permissive to the propagation of CyHV-2.This research was carried out under the National Surveillance Program of Aquatic Animal Diseases, National Fisheries Development Board, Department of Animal Husbandry, Dairying and Fisheries (Grant Number: NFDB/Coord/NBFGR/ 2012-13/16720 dated 11.02.2013) and ICAR National Fellow Scheme of ICAR (ICAR letter no F.No Agri.edn.27/2/2015 HRD dated 13.02.2017), Department of Agricultural Research and Education, Ministry of Agriculture and Farmer’s Welfare, Government of India

Development, nutrition, and rearing practices of relevant catfish species (Siluriformes) at early stages

Catfish (Siluriformes) are important species for aquaculture worldwide, with an annual production in 2018 of ca. 6 million t. This review focuses on reassessing larval development, first feeding, and early rearing practices of the most important farmed catfish species, along with some candidate species for aquaculture diversification: Pangasianodon hypophthalmus (Pangasiidae), Clarias gariepinus (Clariidae), Ictalurus punctatus (Ictaluridae), Pseudoplatystoma spp. (Pimelodidae), Heteropneustes fossilis (Heteropneustidae), Rhamdia quelen (Heptapteridae), Ompok bimaculatus (Siluridae), and Lophiosilurus alexandri (Pseudopimelodidade). These species are initially reared indoors from one day to two weeks and are then transferred to fertilised outdoor ponds where they either feed on natural zooplankton or compound feeds. With the exception of C. gariepinus, I. punctatus, R. quelen and P. hypophthalmus, consistent and reliable fry production is a bottleneck that limits the expansion of farming of other species, such as Pseudoplatystoma spp., H. fossilis, O. bimaculatus, and L. alexandri. Rearing systems (extensive, semi-extensive, intensive) and feeding protocols vary with species and geographical regions. Cannibalism and size heterogeneity are common, and these features create problems for larval and fry rearing of catfish species. Information about their nutritional requirements is required for the formulation of compound feeds that can guarantee high survival and good growth of catfish fries. However, such knowledge for most species is scarce, although some data are available for I. punctatus. Further genomic resources might allow fine-tuning rearing success. This review describes some successes in this field, and also highlights gaps in knowledge to guide future research that can promote the development of catfish aquaculture

Development, nutrition, and rearing practices of relevant catfish species (Siluriformes) at early stages

WOS:000662174500001International audienceCatfish (Siluriformes) are important species for aquaculture worldwide, with an annual production in 2018 of ca. 6 million t. This review focuses on reassessing larval development, first feeding, and early rearing practices of the most important farmed catfish species, along with some candidate species for aquaculture diversification: Pangasianodon hypophthalmus (Pangasiidae), Clarias gariepinus (Clariidae), Ictalurus punctatus (Ictaluridae), Pseudoplatystoma spp. (Pimelodidae), Heteropneustes fossilis (Heteropneustidae), Rhamdia quelen (Heptapteridae), Ompok bimaculatus (Siluridae), and Lophiosilurus alexandri (Pseudopimelodidade). These species are initially reared indoors from one day to two weeks and are then transferred to fertilised outdoor ponds where they either feed on natural zooplankton or compound feeds. With the exception of C. gariepinus, I. punctatus, R. quelen and P. hypophthalmus, consistent and reliable fry production is a bottleneck that limits the expansion of farming of other species, such as Pseudoplatystoma spp., H. fossilis, O. bimaculatus, and L. alexandri. Rearing systems (extensive, semi-extensive, intensive) and feeding protocols vary with species and geographical regions. Cannibalism and size heterogeneity are common, and these features create problems for larval and fry rearing of catfish species. Information about their nutritional requirements is required for the formulation of compound feeds that can guarantee high survival and good growth of catfish fries. However, such knowledge for most species is scarce, although some data are available for I. punctatus. Further genomic resources might allow fine-tuning rearing success. This review describes some successes in this field, and also highlights gaps in knowledge to guide future research that can promote the development of catfish aquaculture

Development, nutrition, and rearing practices of relevant catfish species (Siluriformes) at early stages

Catfish (Siluriformes) are important species for aquaculture worldwide, with an annual production in 2018 of ca. 6 million t. This review focuses on reassessing larval development, first feeding, and early rearing practices of the most important farmed catfish species, along with some candidate species for aquaculture diversification: Pangasianodon hypophthalmus (Pangasiidae), Clarias gariepinus (Clariidae), Ictalurus punctatus (Ictaluridae), Pseudoplatystoma spp. (Pimelodidae), Heteropneustes fossilis (Heteropneustidae), Rhamdia quelen (Heptapteridae), Ompok bimaculatus (Siluridae), and Lophiosilurus alexandri (Pseudopimelodidade). These species are initially reared indoors from one day to two weeks and are then transferred to fertilised outdoor ponds where they either feed on natural zooplankton or compound feeds. With the exception of C. gariepinus, I. punctatus, R. quelen and P. hypophthalmus, consistent and reliable fry production is a bottleneck that limits the expansion of farming of other species, such as Pseudoplatystoma spp., H. fossilis, O. bimaculatus, and L. alexandri. Rearing systems (extensive, semi-extensive, intensive) and feeding protocols vary with species and geographical regions. Cannibalism and size heterogeneity are common, and these features create problems for larval and fry rearing of catfish species. Information about their nutritional requirements is required for the formulation of compound feeds that can guarantee high survival and good growth of catfish fries. However, such knowledge for most species is scarce, although some data are available for I. punctatus. Further genomic resources might allow fine-tuning rearing success. This review describes some successes in this field, and also highlights gaps in knowledge to guide future research that can promote the development of catfish aquaculture.info:eu-repo/semantics/acceptedVersio