Effect of nitrite on early-life stages of common carp (Cyprinus carpio L.)

Nutrient Removal Efficiency and Growth of Watercress (Nasturtium officinale) under Different Harvesting Regimes in Integrated Recirculating Aquaponic Systems for Rearing Common Carp (Cyprinus carpio L.)

The harvesting of plant biomass is usually implemented as an effective tool for plant management and removing the nutrients absorbed in plant tissues. Here, the influence of harvesting different biomasses (50%, 33%, 25%, and 0% (no harvest)) of watercress (Nasturtium officinale) was investigated in integrated recirculating aquaponic systems (IRASs) for rearing common carp (Cyprinus carpio). Twelve independent IRASs were designed (4 × 3); each system consisted of a fish rearing tank, a waste collection tank, and a hydroponic bed. Water quality parameters and the growth of both fish and plants were measured in all the systems, and then the nutrient removal capacities of the hydroponic beds were calculated. The results revealed that increasing the biweekly harvested biomass of the plants decreased the growth of the watercress, while it did not affect the growth of the common carp. Increasing the harvested biomass of the plants also decreased the nitrate nitrogen and orthophosphate removal efficiencies of the aquaponic systems, while it did not affect the ammonia and nitrite nitrogen removal efficiencies. Therefore, a biweekly harvesting of less than 25% of the biomass of the growing watercress is recommended for efficient nutrient removal and the sustainable growth of both watercress and the common carp in aquaponic systems.

Effects of waterborne nitrite on hematological parameters and stress indicators in olive flounders, Paralichthys olivaceus, raised in bio-floc and seawater

Juvenile olive flounders, Paralichthys olivaceus (mean weight 2.69 ± 0.31 g), were raised in bio-floc and seawater for six months, these P. olivaceus (mean weight 280.1 ± 10.5 g, mean length 28.37 ± 2.3 cm) were exposed to different concentrations of waterborne nitrite (0, 25, 50, 100, and 200 mg NO₂^-/L) for 7 days. None of the P. olivaceus individuals exposed to bio-floc and seawater containing waterborne nitrite concentrations of 200 mg/L for 7 days survived. Hematological parameters (hemoglobin and hematocrit) were significantly reduced by nitrite exposure. Regarding plasma components, the concentrations of glucose, glutamic oxalate transaminase (GOT), and glutamic pyruvate transaminase (GPT) increased significantly in response to nitrite exposure, whereas cholesterol concentrations significantly decreased. Stress indicators, including concentrations of plasma glucose, cortisol, and liver and gill concentrations of heat shock protein 70 (HSP70) were significantly increased by nitrite exposure. The results of the study indicate that nitrite exposure affected the hematological parameters and stress indicators of P. olivaceus raised in bio-floc and seawater, and these changes were more prominent in the P. olivaceus raised in seawater than those raised in bio-floc.

The chronic effects of terbuthylazine-2-hydroxy on early life stages of marbled crayfish (Procambarus fallax f. virginalis)

This study assessed the chronic effects of terbuthylazine-2-hydroxy (T2H), one of the main terbuthylazine degradation products, on early life stages of marbled crayfish (Procambarus fallax f. virginalis) by means of mortality, growth rate, early ontogeny, oxidative stress, antioxidant defence and histopathology. The crayfish were exposed to four concentrations of the tested substance as follows: 0.75μg/l (environmental concentration), 75, 375 and 750μg/l for 62days. Concentrations over 75μg/l caused lower weight compared to the control group. T2H at 750μg/l caused delay in ontogenetic development. Levels of thiobarbituric acid reactive substances and total superoxide dismutase activity were significantly (p<0.01) lower in groups exposed to 375 and 750μg/l T2H. Crayfish in these treatments also showed alteration of tubular system including disintegration of tubular epithelium with complete loss of structure in some places of hepatopancreas and wall thinning up to disintegration of branchial filaments with focal infiltrations of hemocytes. In conclusion, chronic terbuthylazine-2-hydroxy exposure in concentrations up 75μg/l (100 times higher than environmental concentration) affected growth, ontogenetic development, antioxidant system, caused oxidative stress and pathological changes in hepatopancreas of early life stages of marbled crayfish.

Effect of single and combination of three triazine metabolites at environmental concentrations on early life stages of common carp (Cyprinus carpio L.)

The sensitivity of early life stages of common carp (Cyprinus carpio L.) to chronic exposure to single and combined environmental concentrations of the triazine metabolites terbuthylazine 2-hydroxy, terbuthylazine-desethyl and atrazine 2-hydroxy was evaluated under laboratory conditions. Their effects were assessed on lipid peroxidation, antioxidant enzymes (total superoxide dismutase, glutathione reductase, catalase, glutathione S-transferase, reduced glutathione), mortality, growth, development and histology. Single metabolites (terbuthylazine 2-hydroxy-0.73 μg/L; terbuthylazine-desethyl-1.80 μg/L; atrazine 2-hydroxy-0.66 μg/L) and combinations were not associated with negative effects on hatching, behaviour, embryo viability, growth or early ontogeny. Carp exposed to terbuthylazine-desethyl at 1.80 μg/L showed significantly lower total superoxide dismutase and glutathione reductase activity compared with the control group. Liver histology revealed diffused steatosis associated with the presence of lipid inclusions in hepatic cells in groups exposed to terbuthylazine-desethyl, atrazine 2-hydroxy and the tested combination of metabolites.

Short-term toxicity of ammonia, nitrite, and nitrate to early life stages of the rare minnow (Gobiocypris rarus)

Nitrogenous pollutants including ammonia, nitrite, and nitrate are a widespread concern in natural waters and aquaculture. In the present study, the toxicity of ammonia, nitrite, and nitrate to rare minnow (Gobiocypris rarus) in the early life stage were evaluated by 2 short-term toxicity tests. In the short-term toxicity test, conducted on embryo and sac-fry stages, 30 fertilized eggs with 3 replicates were randomly exposed to varying levels of ammonia, nitrite, and nitrate until 3 d posthatch (dph). In the 7-d larval subchronic toxicity test, 30 newly hatched larvae with 3 replicates were randomly exposed to varying levels of ammonia, nitrite, and nitrate until 7 dph. The results showed that the 7-d larval subchronic toxicity test was more sensitive than the short-term toxicity test on embryo and sac-fry stages. Both toxicity tests revealed that ammonia was most toxic to rare minnows, followed by nitrite and nitrate. High levels of ammonia, nitrite, and nitrate decreased growth, retarded development, and increased mortality. The no-observed-effect concentrations of ammonia, nitrite, and nitrate for larval growth were 2.49 mg L(-1) , 13.33 mg L(-1) , and 19.95 mg L(-1) nitrogen, respectively. The present study's results demonstrate that nitrogenous pollutants pose a threat to wild populations of rare minnows and provide useful information for establishing water quality criteria for this laboratory fish. Environ Toxicol Chem 2016;35:1422-1427. © 2015 SETAC.

Effects of the terbuthylazine metabolite terbuthylazine-desethyl on common carp embryos and larvae

Toxicity of terbuthylazine-desethyl to embryos and larvae of common carp (Cyprinus carpio) was assessed. Based on mortality, the lethal concentration of terbuthylazine-desethyl was estimated to be 31days LC50=441.6μg/L. Carp exposed to terbuthylazine-desethyl at 1800μg/L exhibited lower weight and length at 7days of exposure compared to the control group. By day 20, carp exposed to 900μg/L terbuthylazine-desethyl showed lower weight and length compared to control group. Terbuthylazine-desethyl in concentrations (180, 900, and 1800μg/L) caused delay in ontogenetic development. Total superoxide dismutase activity was significantly lower in all exposed groups. Exposure to 180 and 900μg/L terbuthylazine-desethyl was associated with alteration of the caudal kidney tubular system including peritubular dilatation detachment of epithelial cells from the basal lamina, and focal autolytic disintegration of the tubular epithelia. Chronic terbuthylazine-desethyl exposure affected survival, growth, ontogenetic development, and the antioxidant system and caused pathological changes to the caudal kidney.

Effects of prometryne on early life stages of common carp (Cyprinus carpio L.)

Toxicity of prometryne to early life stages of common carp was assessed. On the basis of accumulated mortality in the experimental groups lowest observed-effect concentration (LOEC) was estimated as 1100 µg/l; and no observed-effect concentration (NOEC) was 850 µg/l. Fulton's condition factor was significantly lower than in controls in fish exposed to 4000 µg/l after 7, 14, and 21 days. By day 14, fish exposed to 4000 µg/l prometryne showed significantly lower mass and total length compared to controls. Fish exposed the 1200 and 4000 µg/l showed delay in development, severe hyperaemia in gill, liver, and caudal and cranial kidney. Subchronic prometryne exposure of early-life stages of common carp at concentrations of 1200 and 4000 µg/l affected their survival, growth rate, early ontogeny, and histology.

Toxic effects, bioconcentration and depuration of verapamil in the early life stages of common carp (Cyprinus carpio L.)

Verapamil is a pharmaceutical that belongs to a group of calcium channel blockers and is mainly used as a treatment of angina pectoris and arterial hypertension. Verapamil has been detected in aquatic environments in concentrations ranging from ng L(-1) to μg L(-1). In the present study, a series of acute toxicity tests of verapamil on various developmental stages of common carp (Cyprinus carpio) were conducted. As a result, 96hLC50 values of verapamil were estimated at 16.4±9.2, 7.3±1.5 and 4.8±0.2 mg L(-1) for embryos (E5-E9) and common carp larvae L2 and L5, respectively. Lethal concentrations of verapamil decreased with an increase in the age of the fish. Acute exposure to verapamil significantly reduced the heart rate in the embryos and larvae. In an embryo-larval toxicity test (sub-chronic exposure), the bioconcentration, depuration, and toxic effects of verapamil were assessed in common carp. The fish were exposed to verapamil in a concentration of 0.463 (environmentally relevant), 4.63, 46.3 and 463 μg L(-1). Verapamil had no effect on the accumulated mortality, hatching, condition factor, growth or ontogeny of the fish in any of the tested concentrations. In carp exposed to 463 and 46.3 μg L(-1) of verapamil, significantly higher occurrences of malformations and edemas were observed compared to the control. The bioconcentration factor of verapamil in whole fish homogenates ranged between 6.6 and 16.6 and was therefore below the critical value for hazard substances (BCF>500). The half-life and the 95% depuration time for the tested compound were estimated to be 10.2±1.6 days and 44.2±8.6 days, respectively. No effects of verapamil on the studied endpoints were observed at environmentally relevant concentrations.

A dense genetic linkage map for common carp and its integration with a BAC-based physical map

Background

Common carp (Cyprinus carpio) is one of the most important aquaculture species with an annual global production of 3.4 million metric tons. It is also an important ornamental species as well as an important model species for aquaculture research. To improve the economically important traits of this fish, a number of genomic resources and genetic tools have been developed, including several genetic maps and a bacterial artificial chromosome (BAC)-based physical map. However, integrated genetic and physical maps are not available to study quantitative trait loci (QTL) and assist with fine mapping, positional cloning and whole genome sequencing and assembly. The objective of this study was to integrate the currently available BAC-based physical and genetic maps.

Results

The genetic map was updated with 592 novel markers, including 312 BAC-anchored microsatellites and 130 SNP markers, and contained 1,209 genetic markers on 50 linkage groups, spanning 3,565.9 cM in the common carp genome. An integrated genetic and physical map of the common carp genome was then constructed, which was composed of 463 physical map contigs and 88 single BACs. Combined lengths of the contigs and single BACs covered a physical length of 498.75 Mb, or around 30% of the common carp genome. Comparative analysis between common carp and zebrafish genomes was performed based on the integrated map, providing more insights into the common carp specific whole genome duplication and segmental rearrangements in the genome.

Conclusion

We integrated a BAC-based physical map to a genetic linkage map of common carp by anchoring BAC-associated genetic markers. The density of the genetic linkage map was significantly increased. The integrated map provides a tool for both genetic and genomic studies of common carp, which will help us to understand the genomic architecture of common carp and facilitate fine mapping and positional cloning of economically important traits for genetic improvement and modification.

Characterization of common carp transcriptome: sequencing, de novo assembly, annotation and comparative genomics

BACKGROUND

Common carp (Cyprinus carpio) is one of the most important aquaculture species of Cyprinidae with an annual global production of 3.4 million tons, accounting for nearly 14% of the freshwater aquaculture production in the world. Due to the economical and ecological importance of common carp, genomic data are eagerly needed for genetic improvement purpose. However, there is still no sufficient transcriptome data available. The objective of the project is to sequence transcriptome deeply and provide well-assembled transcriptome sequences to common carp research community.

RESULT

Transcriptome sequencing of common carp was performed using Roche 454 platform. A total of 1,418,591 clean ESTs were collected and assembled into 36,811 cDNA contigs, with average length of 888 bp and N50 length of 1,002 bp. Annotation was performed and a total of 19,165 unique proteins were identified from assembled contigs. Gene ontology and KEGG analysis were performed and classified all contigs into functional categories for understanding gene functions and regulation pathways. Open Reading Frames (ORFs) were detected from 29,869 (81.1%) contigs with an average ORF length of 763 bp. From these contigs, 9,625 full-length cDNAs were identified with sequence length from 201 bp to 9,956 bp. Comparative analysis revealed that 27,693(75.2%) contigs have significant similarity to zebrafish Refseq proteins, and 24,371(66.2%), 24,501(66.5%) and 25,025(70.0%) to teraodon, medaka and three-spined stickleback refseq proteins. A total of 2,064 microsatellites were initially identified from 1,730 contigs, and 1,639 unique sequences had sufficient flanking sequences on both sides for primer design.

CONCLUSION

The transcriptome of common carp had been deep sequenced, de novo assembled and characterized, providing the valuable resource for better understanding of common carp genome. The transcriptome data will facilitate future functional studies on common carp genome, and gradually apply in breeding programs of common carp, as well as closely related other Cyprinids.

Nitrite toxicity assessment in Danio rerio and Poecilia reticulata

Nitrite is a natural component of the nitrogen cycle in the environment. Although it usually occurs in low concentrations, elevated concentrations caused by effluents or affected nitrification process can lead to serious health deterioration of fish. Two aquarium fish zebrafish (Danio rerio) and guppy (Poecilia reticulata) are recommended to use as model organisms in toxicity tests. However, their sensitivity to nitrite can differ. The aim of this study was to define acute toxicity of nitrite by the semistatic method according to OECD No. 203 (Fish, Acute toxicity test). The series of 4 acute toxicity tests was performed, with 10 fish of both species used for each concentration and for the control. The 96hLC50 NO2- value for D. rerio and P. reticulata was 242.55 ± 15.79 mg·l-1 and 30.2 ± 8.74 mg·l-1, respectively. We have proved significant difference (p < 0.05) in sensitivity between D. rerio and P. reticulata. The results showed different sensitivities to nitrites in tested fish species, which could be related to species-specific branchial chloride uptake mechanism. This is the first study on this fish species.

Generation of the first BAC-based physical map of the common carp genome

Background

Common carp (Cyprinus carpio), a member of Cyprinidae, is the third most important aquaculture species in the world with an annual global production of 3.4 million metric tons, accounting for nearly 14% of the all freshwater aquaculture production in the world. Apparently genomic resources are needed for this species in order to study its performance and production traits. In spite of much progress, no physical maps have been available for common carp. The objective of this project was to generate a BAC-based physical map using fluorescent restriction fingerprinting.

Result

The first generation of common carp physical map was constructed using four- color High Information Content Fingerprinting (HICF). A total of 72,158 BAC clones were analyzed that generated 67,493 valid fingerprints (5.5 × genome coverage). These BAC clones were assembled into 3,696 contigs with the average length of 476 kb and a N50 length of 688 kb, representing approximately 1.76 Gb of the common carp genome. The largest contig contained 171 BAC clones with the physical length of 3.12 Mb. There are 761 contigs longer than the N50, and these contigs should be the most useful resource for future integrations with linkage map and whole genome sequence assembly. The common carp physical map is available at http://genomics.cafs.ac.cn/fpc/WebAGCoL/Carp/WebFPC/.

Conclusion

The reported common carp physical map is the first physical map of the common carp genome. It should be a valuable genome resource facilitating whole genome sequence assembly and characterization of position-based genes important for aquaculture traits.