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The aim of the present study was to optimize the solid state co‐fermentation requirements of soybean meal (SBM) by Bacillus subtilis and B. licheniformis and assess the application effects on the feeding of koi carp. The soluble protein conversion rate (SPCR) was the highest when co‐fermented by B. subtilis and B. licheniformis with the mixed ratio 1:2 (V/V, marked as SL1:2). As the results of response of surface methodology showed, the optimal co‐fermentation requirements by SL1:2 were at inoculums size 5% under the duration of 60 h at 30°C and with the substrate/water ratio 1:1. The highest SPCR was 50.22% ± 2.06%, and the anti‐nutrient factors in fermented soybean meal (FSBM) decreased significantly (p < 0.05). Six isonitrogenous diets were formulated. Fish meal (FM) was partially replaced by 0%, 30% and 60% of FSBM in the treatment groups, and FSBM replaced by SBM as controlled group. When FM was replaced by 0% and 30% of FSBM, the effects of FSBM on protease activity, immune activity and antioxidant activity of Koi were higher than that of the same proportion of SBM. Meanwhile, the effects of FSBM on the feeding of koi carp could reduce the dosage of 10% SBM at the same proportion. As the results show, FSBM used in aquaculture effectively reduced feed expenditure, improved economic and environmental benefits, and prevented the deterioration of water quality. [ABSTRACT FROM AUTHOR]

Acyclovir inhibits CyHV-3 replication in a dose-dependent manner. The viral load in the CyHV-3-infected, ACV-treated group was divided by the viral load in CyHV-3-infected control and the outcomes were expressed as a percent of the control. Contrary to Troszok et al., (2018) that suggested 66.67 µM as a maximal safe concentration of ACV, Quijano Cardé et al. (2020) showed that even 1500 µM of ACV was safe for the koi carp fin (KF1) cell line. [Extracted from the article]

Adult koi carp (Cyprinus carpio L.) were fed with feed supplemented with vitamin C at 200 mg/kg feed (T1), 400 mg/kg feed (T2) and 600 mg/kg feed (T3), and vitamin E at 200 mg/kg feed (T4), 400 mg/kg feed (T5) and 600 mg/kg feed (T6) at ad libitum for 60 days. Control (without vitamin inclusion) was also maintained. Observations were made on the growth performance, GSI and biochemical composition of gonads such as crude protein, crude fat, cholesterol and carotenoid once in 15 days. At the end of the experiment, fertilization was done to record the fertilization and hatching rate. The difference in the values was noticed among the male and female koi carp. Fish supplemented with vitamin E at 200 mg/kg feeexhibited higher growth in both male and female fish, and the fertilization rate and hatching rate were also higher in that group, and the values were significantly different (p < 0.05) and showed linear and quadratic trends. Inclusion of vitamin C at 600 mg/kg feed had shown higher lipid and carotenoid contents of female koi carp (p<0.05). Hence, the results revealed that supplementing vitamin C and E in the diet is necessary for the successful reproduction of koi carp. [ABSTRACT FROM AUTHOR]

Although the application of treated wastewater in irrigation is a common practice in Jordan, there are no studies on its use in fish culture. In this study, physical, chemical and biological characteristics of an artificial lake containing mixture of treated wastewater and rainwater were assessed to examine whether the nutrient loading is sufficient for fish culture. The study also evaluated the suitability of the lake's water quality for irrigation after fish farming. The study was conducted in outdoor tanks fed with water from the artificial lake and stocked with three types of fish (Tilapia, Carp and Koi). The diversity of phytoplankton communities in the lake's produces natural food for Carp and Koi and promotes their growth with maximum per cent survival of 89% and 56% respectively. In addition, remarkable improvement in all water quality parameters after fish culture was observed. [ABSTRACT FROM AUTHOR]

In order to explore the influence of dietary selenium supplementation on growth, ornamental features and health status of Koi carp, yield of Lettuce, and water quality under aquaponic condition. Koi (125.26 ± 12.55 g) were fed diets containing 0, 0.6, 1.2 and 2.4 mg nano‐Se kg‐1 for 8 weeks respectively. The weight gain rate in 0.6 and 1.2 mg/kg nano‐Se group was significantly higher than control group (p <.05), feed conversion ratio in 1.2 mg/kg nano‐Se group was significantly lower than control (p <.05). Carotenoids content in tissues was significantly increased in 1.2 mg/kg nano‐Se group compared with control (p <.05), and skin redness of 2.4 mg/kg nano‐Se group was significantly higher than control (p <.05). Malondialdehyde level in 1.2 mg/kg nano‐Se group was significantly lower than the control and 2.4 mg/kg nano‐Se group (p <.05). Total serum protein content increased significantly in 1.2 and 2.4 mg/kg nano‐Se groups compared with control (p <.05), and serum globulin increased significantly in 2.4 mg/kg nano‐Se group compared with control (p <.05). The yield of lettuce was not influenced by the dietary Se (p >.05). The ammonia and nitrite in 1.2 mg/kg nano‐Se group were significantly lower than that in control (p <.05). The quadratic regression model of growth and dietary Se levels showed that optimal amount of Se was 1.55–1.57 mg/kg. Overall, dietary nano‐Se supplementation could improve the growth, pigment deposition and health status of Koi and effectively improve the aquaculture environment under aquaponic condition. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are endogenous small non‐coding RNAs that play important roles in many biological processes. The function of miRNAs in skin colour differentiation and pigmentation has been reported in many animals. However, the researches about their molecular mechanisms of regulating the formation of different skin colour of koi carp (Cyprinus carpio L.) are deficient. In this study, we detected the temporal and spatial expression levels of ccr‐miR‐196a (hereinafter referred to as miR‐196a) and then predicted its target mRNA of microphthalmia‐associated transcription factor a (mitfa), which is a key regulatory transcript factor in the melanogenesis pathway, with bioinformatics and dual‐luciferase reporter methods. Furthermore, we silenced the miR‐196a in vivo with an antagomir to detect whether the miR‐196a would affect the expression levels of mitfa mRNA and its downstream genes including tyrosinase (tyr), tyrosinase‐related protein 1 (tyrp1) and dopachrome tautomerase (dct). The results revealed that mitfa and its downstream genes' mRNA expressions all significantly increased in the treatment group compared with the control group. We presumed that miR‐196a might regulate the pigmentation of koi carp through targeting the mitfa. The finding provided the fundamental information regarding miRNA–mRNA interaction on different skin colour pigmentation in koi carp. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate reproductive ability of backcross triploid koi (Cyprinus carpio L.) × goldfish (Carassius auratus L.) hybrids. These triploids have been obtained by crossing of F1 hybrid females producing diploid eggs with males of parental species. Triploid hybrid females, when crossed with goldfish or koi males, produced mostly aneuploid fish with ploidy range from approximately 2.2n–3.2n with a mean value 2.5n; some fish in crosses of triploid females with koi males were tetraploid (4.0n). Since analysed fish had in their genomes one haploid set from parental males, the data indicate that triploid hybrid females mostly produced aneuploid eggs with ploidy range from approximately 1.2n–2.2n and a mean ploidy around 1.5n while some eggs were triploid. Triploid hybrid males were completely sterile and have not released any sperm after hormonal injection. Despite their low viability, some aneuploid fish obtained from triploid hybrid females were raised in indoor recirculating systems until the age of 2 years and their reproductive ability has been evaluated. One aneuploid female with ploidy 2.1n produced larvae with ploidy range from 2.9n to 3.4n with a mean ploidy of 3.1n when crossed with a koi male; about 60% of obtained larvae had ploidy from 3.0n to 3.2n. These data indicate that this female produced mostly eggs with unreduced ploidy level. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to investigate the reproductive ability of second generation (F2) koi (Cyprinus carpio L.) × goldfish (Carassius auratus L.) hybrids. Only diploid F2 males and females were fertile and used in crosses. A significant increase was recorded in male fertility in F2 versus F1. In contrast with an earlier study in which only one fertile F1 male was found, about 20% of F2 males produced sperm. The observed reproductive ability of F2 hybrids was similar to that demonstrated by the only fertile F1 male and F1 females. F2 males produced diploid spermatozoa and generated triploids when crossed with koi females. All triploid fish in these progenies were males indicating that F2 males had a sex chromosome constitution of XY. F2 females produced diploid eggs and generated mostly triploids when crossed with koi males. In progenies obtained by crosses of F2 males with F1 and F2 females, most of the surviving juveniles (63%–100%) were diploid; a minority of juveniles were aneuploid (ploidy ranged from 2.1n to 3.6n). Diploid fish in these progenies were presumably the result of spontaneous androgenesis and gynogenesis, by the same mechanisms observed earlier in progenies obtained by crossing the F1 male with F1 females. [ABSTRACT FROM AUTHOR]

This study explores the anaesthetic activity of Alpinia galanga oil (AGO) in fish. Cyprinus carpio (koi carp) was used as a fish model. It was found that the induction time to stage 3 anaesthesia and the recovery time of the fish after exposure to AGO were exponentially and polynomially correlated to AGO concentrations. The viability of normal blood cells of koi carp anaesthetized with 500 mg/L AGO was found to be higher than 90% for normal red blood cells and white blood cells and 89% for peripheral blood nuclear cells indicating nontoxicity of AGO to the fish. A concentration of 300 mg/L of AGO was the most suitable for anaesthetizing koi carp due to the safety and effectiveness aspects as being ideally fitted to anaesthetic criteria. This concentration gave the induction time of 205.55 ± 5.07 s and the recovery time of 202.50 ± 9.30 s. Determination of stress biomarker such as blood cortisol and glucose as well as gene expression showed that the blood cortisol level of the fish anaesthetized with AGO was similar to normal levels. Moreover, blood glucose level was significantly less increased than those anaesthetized with tricaine methanesulfonate. Gene expressions of the fish cortisol receptor, cytochrome oxidase subunit1, heat shock protein 70 and Na+/K+-ATPaseα3 were significantly reduced after exposure to AGO indicating the advantages of AGO on fish stress reduction. Thus, AGO is a promising natural source for an alternative fish anaesthetics. [ABSTRACT FROM AUTHOR]

Abstract: A 60‐day growth experiment was conducted to investigate the effect of dietary replacement of fishmeal by Spirulina platensis on growth performance, digestion and physiological parameters in juvenile gibel carp (5.0 ± 1.0 g). Four diets were formulated to replace 0 (SP0), 50% (SP50), 75% (SP75) and 100% (SP100) of dietary fishmeal protein by S. platensis respectively. Other two diets based on SP100 were supplemented with 2% dicalcium phosphate (SP100 + P) or 0.28% coated lysine (SP100 + Lys). The results showed that no significant differences of specific growth rate (SGR), feed efficiency (FE), feeding rate (FR) and protein efficiency ratio (PER) were observed between SP0 group and the replacement groups (SP50, SP75 and SP100). FE and PER of fish‐fed SP100 + Lys diet were significantly higher than the fish‐fed SP100 diet (p < .05). Apparent digestibility coefficients (ADCs) of dry matter, protein, energy and phosphorus increased significantly with the increasing S. platensis inclusion. Meanwhile, fish from SP100 + P or SP100 + Lys group had higher ADCs of nutrients compared to the SP100 group (p < .05). Compared with SP0 diet, fish‐fed S. platensis diets had higher activities of plasma superoxide dismutase, hepatopancreas total antioxidant capacity, plasma alkaline phosphatase and plasma lysozyme, as well as the lower content of plasma malondialdehyde. The present results indicated that dietary fishmeal could be fully replaced by S. platensis without any negative effects on growth performance of gibel carp. Supplementation of lysine in the S. platensis replacement diet could further improve the feed utilization of gibel carp. [ABSTRACT FROM AUTHOR]

Abstract: A 57‐day growth experiment was conducted with juvenile gibel carp (13.48 ± 0.10 g) in a flow‐through system to study the effect of dietary phosphorus on growth performance, body composition, nutrition utilization, phosphorus loading and enzymes activities. Seven semipurifed diets were formulated to contain 0.07 (the basal), 2.27, 5.32, 8.10, 12.06, 15.24 and 19.48 g available phosphorus/kg diet. The results showed that specific growth rate, body length and feed efficiency significantly increased in the fish fed diets containing 0.07 to 15.24 g available P/kg diet (p < .05). Ash and P content increased in fish fed diets containing 0.07–12.06 P g/kg (p < .05) and then levelled off, while moisture, crude protein and lipid had no significant difference (p > .05). The protein retention efficiency increased in the fish fed with diets 0.07–5.32 g/kg P (p < .05) and then reached a plateau. The P content in faeces was higher in fish fed diets containing 15.24 and 19.48 g available P/kg. Total P concentration in tank water increased in fish fed 0.07–12.06 g available P per kg diet (p < .05). The plasma P was higher in the fish fed with 15.24 g available P/kg diet (p < .05), triglycerides was lower in the fish fed diet containing 15.24 and 19.48 g available P/kg (p < .05), no significant differences were observed in plasma Ca, plasma glucose and calcitonin (p > .05). Based on SGR, whole body P content and FE, dietary available P requirement for juvenile gibel carp were 13.37, 13.97 g/kg and 15.06 respectively. [ABSTRACT FROM AUTHOR]

Abstract: An 88‐day experiment was conducted in a flowing system to evaluate the effects of dietary vitamin C on growth, body composition, antioxidant and gonad development of on‐growing gibel carp. Triplicate tanks of gibel carp (77.2 ± 0.1 g) were randomly fed with one of seven experimental diets containing l‐ascorbic acid of 0, 101.1, 188.5, 313.1, 444.1, 582.1 and 747.0 mg/kg, respectively. The results showed that specific growth rate (SGR) and feed efficiency (FE) of fish were not affected by dietary l‐ascorbic acid. Dietary l‐ascorbic acid of 444.1 mg/kg diet led to low levels (p < .05) of gonadosomatic index (GSI) and hypothalamic gonadotropin‐releasing hormone (GnRH) in on‐growing fish, as well as the early ovarian stages (Developing stages) compared with fish (Maturing stages) from the other groups. Dietary l‐ascorbic acid supplementation increased (p < .05) the dorsal muscle collagen content, but did not affect the protein or lipid content of dorsal muscle in gibel carp. Plasma total antioxidant capacity (T‐AOC) and superoxide dismutase (SOD) activity increased (p < .05) and then remained unchanged with the increase in dietary l‐ascorbic acid levels. Dietary l‐ascorbic acid of 101.1 mg/kg diet improved (p < .05) plasma lysozyme activity of the fish. Broken‐line regression indicated that dietary l‐ascorbic acid requirement of 77 g gibel carp was 223.3 or 225.0 mg/kg diet based on plasma T‐AOC or SOD activity, which was a little higher than that based on plasma l‐ascorbic acid concentration (193.2 mg/kg). [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the effect of dietary bamboo charcoal (BC) supplementation on the growth performance and health status of juvenile common carp (Cyprinus carpio L.). A 63‐day feeding trial was carried out wherein the carp were reared on diets containing increasing levels of BC (0%, 0.5%, 1%, 2% and 4%). Treatment with BC did not produce any obvious effect (p > .05) on the growth performance of the juvenile common carp and on the overall muscle fatty acid composition. However, significant improvements (p < .05) were reported on serum indicators such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein (TP), triglycerides (TG), total cholesterol (TC), high density lipoprotein (HDL) and glucose (GLU) with the 4% inclusion level producing the most beneficial effects without adversely affecting some of the indices that were not improved at this level. Improvements were further observed in the intestinal villus length and goblet cells numbers at 4% supplementation. Although some evidence of potential toxicity exists, the overall findings of this study suggest that supplementation of common carp diets with 4% BC has a potential to enhance serum biochemical indices, intestinal functions and fatty acid content in common carp. Furthermore, while no positive effects were observed on the growth performance and total muscle fatty acid composition, no adverse effects were reported on these parameters. Therefore, BC has the potential to be used as a feed additive in the diets of juvenile common carp to improve health status and intestinal function. [ABSTRACT FROM AUTHOR]

Inheritance and segregation at five microsatellite loci were studied in diploid gynogenetic and triploid backcross progenies obtained from koi × goldfish hybrid females, which produce diploid eggs. Gynogenetic and backcross progenies were obtained from three individual hybrid females by inseminating eggs with genetically inactivated and intact sperm of parental species respectively; no shock treatments were applied to the early embryos. Complete absence of paternally specific alleles at all investigated microsatellite loci has proven successful genetic inactivation of spermatozoa by irradiation and confirmed gynogenetic origin of progenies. Genotypic segregations at microsatellite loci showed almost complete homogeneity of gynogenetic progenies and their identity to female parents. These results correspond with previous cytogenetic data on the occurrence of premeiotic endomitosis in hybrid females producing diploid eggs. Fish from triploid backcross progenies had genotypes resulting from combination of entire diploid female genome and haploid genome from male. [ABSTRACT FROM AUTHOR]

The Japanese ornamental (koi) carp is a popular decorative fish all over the world. In koi, clones have not yet been obtained, although production of fish with identical colour patterns could be of commercial interest. Mitotic gynogenetic progenies are essential for subsequent production of clones in fish. However, resulting late-shocked progenies may be contaminated with meiotic gynogens from spontaneous suppression of the second meiotic division in eggs. In this study, microsatellite DNA markers were used to confirm mitotic gynogenetic origin of obtained late-shocked progenies. Recombination rate ( y) and mapping distance relative to centromere (M-C) of 10 microsatellite loci were determined based on percentage of heterozygotes in meiotic gynogenetic progenies. The range of y varied from 0.01 to 0.96 and the M-C map ranged from 0.5 to 48 cM. The mean value of y over the 10 loci was 0.481. Six loci, which had y 0.47 and higher, were used as markers in two late-shocked gynogenetic progenies. Complete homozygosity was revealed at all six microsatellite loci indicating mitotic gynogenetic origin of analysed progenies. [ABSTRACT FROM AUTHOR]

Since virus isolation is seldom successful, KHV infection is commonly detected by PCR examination. A number of different PCR assays have been described in recent years. However, at present no commonly accepted PCR method is used amongst different laboratories. The aim of this study was to check if the examination of infected fish by different PCR methods yielded comparable results. We used tissue samples of three KHV-infected koi, one KHV-infected common carp, one KHV-infected goldfish and one non-infected common carp. DNA was extracted with DNAzol Reagent, High Pure PCR Template DNA Preparation Kit and QIAamp DNA Mini Kit. The DNA was tested by PCR with different combinations of published primer sets - KHV-F and -R, KHV-Gray-2F and -2R and KHV- TKf and - TKr - plus different DNA polymerases - a standard Taq DNA polymerase, a Platinum (hotstart) Taq DNA polymerase and a Platinum (hotstart) Pfx DNA polymerase with proofreading activity. The different extraction methods produced DNA solutions with different yields of DNA and different degrees of homogeneity. Also, the sensitivity of the PCR depended on the choice of the primer set and polymerase. Not all infected fish could be identified with all methods; there were large differences in the sensitivity between methods. [ABSTRACT FROM AUTHOR]

To compare the effect of polyculture against conventional monoculture on ornamental carp production, investigations on food selection and growth performance of koi carp (K), Cyprinus carpio L. and goldfish (G), Carassius auratus (L.) were conducted in a 11-week rearing experiment in two monoculture (100% K and 100% G) and five polyculture (90% K–10% G, 70% K–30% G, 50% K–50% G, 30% K–70% G and 10% K–90% G) conditions in tropical ponds. There were three replicates for each treatment. Environmental conditions and food availability were similar in all the treatments. Ivlev's electivity index showed that both fish species avoided phytoplankton and preferred cladocerans to other zooplankton groups (copepods and rotifers) in monotypic conditions. However, in the polyculture treatments, the positive electivity of goldfish towards cladocerans reduced significantly ( P<0.05), while the percentage of copepods, rotifers and phytoplankton in the gut content increased. No significant differences in weight gain, specific growth rate and deformities were recorded at harvest for koi carp between the different treatments ( P>0.05). Even the survival rate of koi carp recorded above 90% in all the treatments. However, the goldfish recorded significantly better weight gain, specific growth rate and survival in monoculture (100% G), compared with the polyculture treatments ( P<0.05). Goldfish deformities were lowest (P<0.05) in the monoculture treatment (2.42%). The number of marketable fish above a set size limit of 4 g total weight was significantly higher in the two monoculture treatments, compared with the five polyculture treatments (P<0.05). Keeping in view of the dietary similarities of koi carp and goldfish, and the aggressive nature of koi carp in polyculture, it is suggested to refrain from polyculture of goldfish and koi carp until further documentations relating to optimum stocking density and management of polyculture of ornamental carps are available. [ABSTRACT FROM AUTHOR]

In this study, a short-term storage of pre-activated eggs of the Japanese ornamental (koi) carp, Cyprinus carpio L., at three different temperature regimes is reported. Koi eggs were stored at low temperatures (6–9 °C), at variable or high temperatures (12–31 °C) and at moderate-stable temperatures (20–24.5 °C). Survival of the developing embryos was examined at the first and the second day post-activation, and in hatch-out larvae. Survival was calculated for each treatment by linear regression Y = a-bX (P ≤ 0.01), except for eggs incubated at temperature of about 20 °C(P > 0.1). The specific mortality index (b/a 100), as a ratio between the mortality rate (b) and the fertilization rate (a), indicated that the highest mortality is associated with the high and unstable storage temperatures, while the lowest mortality is with the moderate and stable storage temperatures. Eggs can be stored at moderate and stable temperatures for a maximal duration of 6 h, yielding survival of hatch-out larvae higher than 50%. In two trials, fertilization potency of sperm stored in a domestic refrigerator (5–9 °C) for 5 h, was compared with freshly stripped sperm and no differences in fertilization rates were found between the two treatments. [ABSTRACT FROM AUTHOR]