Genetic resistance of carp (Cyprinus carpio L.) to Trypanoplasma borreli: influence of transferrin polymorphisms

In serum most of the iron molecules are bound to transferrin (Tf), which is a highly polymorphic protein in fish. Tf is an essential growth factor for mammalian trypanosomes. We performed a series of experiments with Trypanoplasma borreli to detect putative correlations between different Tf genotypes of common carp (Cyprinus carpio L.) and susceptibility to this blood parasite. Five genetically different, commercially exploited carp lines (Israelian 'D', Polish 'R2' and 'K', Ukrainian 'Ur', Hungarian 'R0') and a reference laboratory cross ('R3xR8') were challenged with T. borreli and parasitaemia measured to determine susceptibility to the parasite. Among the commercial carp lines, Israelian 'D' carp were identified as most and Polish 'R2' carp as least susceptible, and used to produce a next generation and reciprocal crosses. These progenies were challenged with T. borreli and parasitaemia measured. We demonstrated significant effects of genetic background of the carp lines on susceptibility to T. borreli. This genetic effect was preserved in a next generation. We also observed a significant male effect on susceptibility to T. borreli in the reciprocal crosses. Serum samples from a representative number of fish from two infection experiments were used for Tf genotyping by polyacrylamide gel electrophoresis (PAGE), identifying DD, DG and DF as most frequent Tf genotypes. We could detect a significant association of the homozygous DD genotype with low parasitaemia in the least susceptible 'R2' (and 'K') carp lines and the lack of a such an association in the most susceptible 'D' carp line. Upon examination of parasite growth in vitro in culture media supplemented with 3% serum taken from fish with different Tf genotypes, we could show a faster decrease in number of parasites in culture media with serum from DD-typed animals.     

Sensitivity and permissivity of Cyprinus carpio to cyprinid herpesvirus 3 during the early stages of its development: importance of the epidermal mucus as an innate immune barrier

Cyprinid herpesvirus 3 (CyHV-3) causes a lethal disease in common and koi carp (Cyprinus carpio). The present study investigated the ability of CyHV-3 to infect common carp during the early stages of its development (from embryos to fingerlings) after inoculation by immersion in water containing the virus. Fish were inoculated at different times after hatching with a pathogenic recombinant CyHV-3 strain expressing luciferase. The sensitivity and permissivity of carp to CyHV-3 were investigated using in vivo bioluminescence imaging. The susceptibility of carp to CyHV-3 disease was investigated by measuring the survival rate. Carp were sensitive and permissive to CyHV-3 infection and susceptible to CyHV-3 disease at all stages of development, but the sensitivity of the two early developmental stages (embryo and larval stages) was limited compared to later stages. The lower sensitivity observed for the early developmental stages was due to stronger inhibition of viral entry into the host by epidermal mucus. In addition, independent of the developmental stage at which inoculation was performed, the localization of light emission suggested that the skin is the portal of CyHV-3 entry. Taken together, the results of the present study demonstrate that carp are sensitive and permissive to CyHV-3 at all stages of development and confirm that the skin is the major portal of entry after inoculation by immersion in infectious water. The results also stress the role of epidermal mucus as an innate immune barrier against pathogens even and especially at the early stages of development.     

Immunotoxicity of aminocarb : I. Comparative studies of sublethal exposure to aminocarb and dieldrin in mice

Immunotoxicity of a carbamate pesticide, aminocarb (Matacil), introduced orally in sublethal doses to C57B1/6 inbred mice, has been compared to the immunosupressive effects of the organochlorine pesticide, dieldrin (served as a positive control), in bacterial and viral infections. In vivo infection of pesticide-exposed mice with Salmonella typhimurium and mouse hepatitis virus 3 (MHV3) showed that two subsequent LD₅₀ doses of aminocarb did not decrease the resistance of animals to the pathogens, whereas exposure to dieldrin resulted in augmented mortality. In vitro studies showed that the spread of MHV3 virus infection and virus-induced cytopathic effects (cpe) were augmented in peritoneal macrophages after exposure to aminocarb, albeit to a much less extent than in the dieldrin group. Similarly, a decrease in the anti-MHV3 IgM serum antibody titer by aminocarb was less marked than in the dieldrin group. Alternatively, immunization of animals with a neutral antigen, sheep red blood cells (SRBC), showed a significant increase in the anti-SRBC humoral response 10 days after a single oral exposure to LD₅₀ aminocarb. The cellular immune response, determined by mixed lymphocyte reaction, was unaffected by sublethal aminocarb exposure. In addition, macrophage antigen processing of a single protein, avidin, was unaffected by aminocarb, contrary to the inhibition of avidin processing in macrophages from dieldrin-gavaged mice. The data do not indicate that immunotoxic properties are associated with aminocarb, and only slight effects with high sublethal doses of orally given aminocarb on macrophage susceptibility to the MHV3 viral pathogen were observed at a terminal phase of the disease.     

The effect of administration of copper nanoparticles to chickens in their drinking water on the immune and antioxidant status of the blood

The aim of this experiment was to determine what dosage of copper (Cu) nanoparticles, added to a standard dietary supplementation with copper sulfate, would improve antioxidant and immune defense in chickens. The experiment was conducted with 126 broiler chickens assigned to seven treatments with three pens per treatment and six broiler chickens per pen. The basal‐diet treatment did not receive Cu nanoparticles (nano‐Cu) and as shown by analyses it was Cu‐deficient (?29% vs. National Research Council (NRC) recommendations; 5.7 vs. 8 mg/kg). Broiler chickens received nano‐Cu (0.5, 1.0 or 1.5 mg/kg body weight per day) via a tube into the crop over three 3‐day periods (days 8–10, 22–24 and 36–38) or three 7‐day periods (days 8–14, 22–28 and 36–42). As a result, in the nano‐Cu‐treated broilers the total experimental Cu intake was from ?11% to +96% versus NRC recommendations. At the age of 42 days of broilers, their blood indices were determined. The obtained results showed that correction of the deficient basal diet of chickens with nano‐Cu to a level of copper exceeding the NRC recommendation by 54% increased the antioxidant potential of the organism and inhibited lipid peroxidation. At the dosage of +96% versus NRC, some symptoms of a deterioration in antioxidant status appeared (a decrease in the level of glutathione plus glutathione disulfide and an increase in superoxide dismutase, catalase and ceruloplasmin activity and in lipid hydroperoxide content). Additionally, +7% versus the recommended Cu dietary level was followed by unfavorable results, indicating a deterioration in red blood cell parameters and stimulation of the immune system (an increase in interleukin‐6, immunoglobulin A (IgA), IgM and IgY). To conclude, it was shown that it is possible to simultaneously increase antioxidant and immune defense of chickens by supplementing their diets with nano‐Cu – up to 12 mg per bird during 6 weeks of feeding, that is to a level no more than 7% over the NRC recommendation for growing broiler chickens.     

Application of RFLP analysis of recA, gyrA and rpoS gene fragments for rapid differentiation of Erwinia amylovora from Erwinia strains isolated in Korea and Japan

Restriction fragment length polymorphism (RFLP) analysis of the PCR amplified fragments of recA, gyrA and rpoS genes was applied for the characterization of Erwinia amylovora and Erwinia strains, which cause fire blight and Asian pear blight in orchards. Primers, constructed on the basis of the published recA, gyrA and rpoS gene sequences of Erwinia carotovora, allowed us to amplify DNA fragments for RFLP differentiation of E. amylovora and E. pyrifoliae and finally to distinguish strains within these species and relate them to pear pathogens from Japan. Three to seven restriction endonucleases were applied for RFLP analysis of each gene fragment. The electrophoretic patterns generated after PCR–RFLP for each of the tested genes, were characteristic and specific for each species and allowed their differentiation. The data show that PCR–RFLP analysis of the recA, gyrA and rpoS gene fragments may be considered as a useful tool for the identification and differentiation of E. amylovora and E. pyrifoliae. Almost identical restriction patterns of the analyzed gene fragments indicated a high relationship of E. pyrifoliae strains from Korea and pear pathogens from Japan and a divergence to E. amylovora. For quick and effective differentiation of E. amylovora strains from Erwinia strains from Asia without nucleotide sequencing we recommend the amplification of recA and rpoS gene fragments and digestion of each of them with restriction endonuclease Hin6I.     

IBR and BVD control: the key to successful herd management

Control of IBR and BVD should be possible in Europe. Effective vaccines and reliable tools for monitoring are available. Systematic approach and strict implementation of control measures are essential. Voluntary or mandatory programs are ongoing on regional or national level in a lot of countries. Successful programs put pressure on surrounding regions/countries to initiate control program as well.     

Developmental competence of eggs produced by rainbow trout Doubled Haploids (DHs) and generation of the clonal lines

Poor quality eggs produced by the fully homozygous doubled haploids (DHs) may impair generation of clonal lines in fish species. In the present research, gynogenetic development of rainbow trout (Oncorhynchus mykiss) was induced in eggs originated from the DH females. Eggs were activated with the UV‐irradiated grayling (Thymallus thymallus) spermatozoa and subjected to the high hydrostatic pressure (HHP) shock to provide diploid clonal individuals. Only two of four DH females produced eggs that were successfully activated by the irradiated spermatozoa and subsequently developed into the gynogenetic embryos. Survival rates of rainbow trout from the clonal lines equalled 21.5% and 19.8% during embryogenesis and decreased after hatching to 18.6% and 14.9%, respectively. Some of the dead rainbow trout clones collected between hatching and swim‐up stage were emaciated and exhibited spinal deformities including scoliosis. Provided results confirmed limited developmental competences of eggs produced by rainbow trout DH females. Clonal rainbow trout developing in such eggs exhibited reduced survival and increased frequency of the body abnormalities.     

Genetic evaluation of reproductive potential in the Zatorska goose under a conservation program

The aim of this study was to estimate the genetic parameters and inbreeding effect on the fertility, embryo mortality and hatchability traits in the Zatorska goose covered by the animal genetic resources conservation program. The material for this study contains information about results of hatching of 18 863 eggs from 721 dams and 168 sires, laid between 1998–2015. Genetic parameters were estimated based on the threshold animal model by the use of Restricted Maximum Likelihood and Gibbs sampling. The percentage of fertilized eggs ranged yearly between 37–80%. The percentage of embryo mortality was very low, ranging between 4.63–23.73%. The percentage of the hatched goslings from the total number of analyzed eggs was on average 33.18%, and 53.72% from fertilized eggs. On average based on both methods, the heritability estimates of the fertility, embryo mortality and hatchability reached 0.36, 0.07, 0.24 for males and 0.44, 0.11, 0.32 for females. The genetic trend had increasing tendency for fertility and hatchability and was stable for embryo mortality for both sexes. The obtained result shows that the Zatorska goose can be still maintained in the reserves of the local gene pool according to current rules and use in the local market as a breed with good reproductive potential.