Atlantic Salmon (Salmo salar) Performance Fed Low Trophic Ingredients in a Fish Meal and Fish Oil Free Diet.

To evolve fish farming in an eco-efficient way, feed production must become less dependent on forage fish-based ingredients and make more use of low trophic level organisms, including microalgae, higher plants, as filter feeding organisms and other ingredients with low competition to established food value chains. Diets nearly free of fish meal and fish oil are not a novelty but are often composed of complex mixtures, containing supplements to meet the farmed animal's nutritional requirements. Sustaining a growing aquaculture production, maintaining at the same time fish health, welfare, and profitability, and meeting strict environmental and food safety demands, is challenging and requires new technologies, great investments, and more knowledge. A benchmarking feeding trial was performed to demonstrate the main effects of four low trophic raw materials on Atlantic salmon (Salmo salar) growth, metabolism, skin health and fillet quality. To this end, a diet was produced to contain commercially relevant levels of fresh high quality organic FM and FO and was used as a control in the trial (FMFO). Heterotrophically produced Schizochytrium limacinum biomass was used to replace organic FO (HM diet). Spray dried cell wall disrupted biomass of the phototrophically cultured diatom Phaeodactylum tricornutum replaced partly FM and FO (PM diet). Black soldier fly (Hermetia illucens) larvae meal and tunicate (Ciona intestinalis) meal, were used to produce the diets BSFL and TM, respectively, replacing large parts of FM as compared to the FMFO. A fifth test diet was produced combining all test raw materials and removing all FM and FO (0FM0FO diet). All test ingredients were well accepted sustaining high growth rates (TGC values near 4) and feed efficiency (FCR values below 0.9) in salmon showing good gut health and normal metabolic responses. However, none of the treatments reached the growth performance of FMFO. Additional differences between test and control treatments were identified in dietary nutrient apparent digestibility, fish biometrics, blood metabolites and fillet and skin composition. Extensive raw material and dietary chemical characterisation was performed to provide insight on potential shortcomings in the novel low trophic level ingredients which can possibly be overcome combining complementary raw materials.

Geographical and temporal distribution of Ockelbo disease in Sweden.

The incidence of Ockelbo disease and the prevalence of Ockelbo virus neutralizing antibodies were investigated in a sample of the Swedish population. The disease occurs throughout most of Sweden but with higher incidence and antibody prevalence rates in the central part of the country. It generally affects middle-aged men and women, with equal incidence between sexes, and is uncommon in people younger than 20 years of age. The disease occurs during a short period each year between the third week of July and the first week of October, with a peak during the second half of August. During the 8 years studied (1981-8), an average of 31 Ockelbo patients/year were diagnosed. The antibody prevalence rates in the oldest age groups were 20-40 times higher than the accumulated life-risk of being diagnosed and reported as an Ockelbo disease patient, which suggests that many cases are asymptomatic and/or unreported.

Ecologic studies of mosquitoes and birds as hosts of Ockelbo virus in Sweden and isolation of Inkoo and Batai viruses from mosquitoes.

Field studies were conducted in central Sweden from 1983 through 1985 to obtain information on the etiologic agent of Ockelbo disease, described in Sweden in the 1960s and probably identical to Pogosta disease in Finland and to Karelian fever in the western USSR. Mosquitoes (63,644) collected during this 3 year period yielded 21 virus strains. Ockelbo virus isolations were from Culiseta morsitans (5 strains), Culex pipiens and/or Cx. torrentium (6 strains), and Aedes cinereus (3 strains). Inkoo (6 strains) and Batai (1 strain) viruses were recovered from Ae. communis. Blood samples collected March-May from migrating birds on the southeast and est coast of Sweden and in July and August from resident birds in east-central Sweden were tested for neutralizing antibody to Ockelbo virus. Antibody was not detected in 328 birds sampled during spring migrations. Two of 58 (3.4%) birds bled in July and 8 of 78 birds (10%) bled in August had antibody to Ockelbo virus. Ockelbo virus circulates in a mosquito-bird-mosquito cycle, with Cs. morsitans and Cx. pipiens and/or Cx. torrentium as enzootic vectors. Antibody was detected in passerine birds. Other classes of birds or other vertebrates were not sampled. Aedes cinereus may serve primarily to transmit virus to people. The role of other mosquito species as vectors for people is unknown.

Ockelbo disease in Sweden: epidemiological, clinical, and virological data from the 1982 outbreak.

An outbreak of Ockelbo disease, a syndrome with rash, arthralgia and moderate fever reactions, which occurred in Sweden 1982 is described. A virus, designated Edsbyn 5/82, isolated from mosquitoes and closely related to Sindbis virus (Togaviridae: Alphavirus) is the probable etiologic agent. Sixty-five patients with typical clinical manifestations of the disease became ill in August 1982 and exhibited antibody titer rises against both Edsbyn 5/82 and Sindbis viruses by indirect immunofluorescence and the mixed hemadsorption technique. With the latter method, but not by the neutralization tests, antibody titers were significantly higher against Edsbyn 5/82 virus than against Sindbis virus. Most cases occurred in central Sweden between the 60th and 63rd parallels. The frequency of antibody in healthy individuals (blood donors) within the endemic area was 2-3% and in foci with high incidence, antibody positivity reached 8%. Antibody frequencies continuously decreased south and north of this area. Antibody decline was followed in a group of 12 patients who had Ockelbo disease in 1981. Mixed hemadsorption titers were 4-6 times higher against Edsbyn 5/82 than against Sindbis virus. A 2- to 4-fold antibody decline took place from early convalescence to 20 months after onset.

Association of a Sindbis-like virus with Ockelbo disease in Sweden.

An alphavirus isolated from Culiseta mosquitoes has been associated with Ockelbo disease, an exanthema arthralgia syndrome occurring in Sweden. The isolate was made from mosquitoes collected in Edsbyn (central Sweden), an area with considerable Ockelbo disease morbidity. This isolate proved to be indistinguishable from Sindbis virus by complement-fixation and hemagglutination-inhibition tests, and was antigenically related to Sindbis in plaque reduction neutralization tests. Patients with Ockelbo disease developed neutralizing antibodies to the virus in their convalescent sera, suggesting that it is the etiologic agent of the disease.

Rubella immunity testing by mixed hemadsorption.

A mixed hemadsorption (MH) test for naturally acquired rubella immunity and immune responses after rubella vaccination has been compared with the hemagglutination-inhibition (HI) test, the immunodiffusion (ID) test, the neutralization test (NT), the hemolysis-in-gel (HIG) test and the indirect immunofluorescence (IF) test. The MH test was approximately equivalent to the HI test and the NT as to sensitivity for the early response to rubella vaccination, and all three tests are thought to measure protective antibodies, i.e. antibodies supposedly directed against envelope antigens, to about the same extent. The MH test for rubella antibodies is especially suited for laboratories in which this type of test is routinely used for other purposes, e.g. rabies, respiratory syncytial virus, herpes simplex, varicella and certain auto-antibodies. Where the method is already standard it may be preferable to the NT which, although of similar clinical value requires tedious standardization. Both tests may be necessary in cases where the HI test is equivocal or hampered by non-removable on-specific inhibitors.

Tissue typing of cells in culture. II. Histocompatibility typing of diploid fibroblastic cultures by the mixed hemadsorption (MH) test.

Skin fibroblasts derived from persons who had been HLA-typed by conventional lymphocytotoxocity tests were subjected to HLA-typing by the mixed hemadsorption (MH) test. The agreement between the two methods was good, provided sera for the MH test were carefully selected. Minor discrepancies found in this study can probably be corrected by further serum selection. There was no difficulty in typing late passages of cultured diploid cells (22 doublings) and in fact it was easier to type a culture at the 33rd doubling than at the 11th. Thus no signs of disappearance of HLA-antigens were seen in these tests.

Tissue typing of cells in culture. IV. Cell surface antigens of tumor cell lines, not obviously belonging to the HLA-system.

Studies on the HLA pattern of several human tumor cell lines by the mixed hemadsorption test and also studies on the discriminative patterns formed by a collection of sera on a number of cell lines and diploid cells have been reported elsewhere. It was noted during these studies that some sera reacted in a fashion indicating that they did not represent any of the HLA-A or -B series and probably not the HLA-C series either. The corresponding antigenic determinants were tentatively designated Ek-1 to Ek-11. The pattern of these antigens among the cell lines is given in a table and it seems apparent that the Ek-series considerably increases the cell identification potential of the typing results. So far, five of the sera determining the Ek-antigens have failed to be blocked by anti-beta-2-microglobulin, indicating that the antigens do not belong to the HLA-A, B or C series. Preparatory work for HLA-D typing is under way.

The advantage and adequacy of the mixed hemadsorption test for rabies antibody determination.

The goal of rabies vaccination is an early development of protecting antibodies. The mixed hemadsorption (MH) test is shown to be an adequate test to evaluate the immunization response. It measures antibodies combining with antigens on rabies-infected cells equivalent to the glycoprotein antigen at the exterior of the budding virus (1). Further, the MH test used measures antibodies solely of IgG class, thus avoiding positive results being obtained by IgM antibodies which can be produced during a prolonged period because of antigen persistence due to daily immunization doses (2). Antibodies of IgM class may play only a minor role in the early defence against rabies as probably only antibodies of IgG class can reach a locally introduced virus and, so far, are the only immunoglobulins shown to induce immune lysis in rabies-infected cells (3). The MH test is described. It is a sensitive, reliable and technically convenient method as it has a capacity for testing many sera in the same run. Results obtained are compared with neutralization values obtained from different types of rabies vaccines (4).

Long-term follow-up studies on herpes simplex antibodies in the course of cervical cancer: patterns of neutralizing antibodies.

The kinetics of neutralization was used to study antibodies to herpes simplex virus type 2 in 90 patients with invasive carcinoma of the cervix uteri. The first sera were drawn before treatment and consective sera were drawn at intervals thereafter. Control groups consisted of 90 age-matched healthy women and 70 cancer patients suffering from malignancies other than cervix carcinoma. Patients surviving during the observation period of 12-60 months had a significantly higher frequency of neutralizing antibodies than control groups. Twenty-six of the women with cervix carcinoma died during the observation period and 13 others had a recurrence of the cancer. Survivors with advanced cervical cancer had higher antibody titers than survivors with less severe cervical cancer while patients whose cancer caused death had low titer or to a great extent lacked neutralizing antibodies. Women with recurrences and progressing cervical lesions had no detectable antibodies while women with recurrences and regressing lesions all had antibodies. There was a rise in K2-values 6-18 months after treatment. In serum samples collected later than 18 months, there was a return to original levels.

Long-term follow-up studies on herpes simplex antibodies in the course of cervical cancer. II. Antibodies to surface antigen of Herpes simplex virus infected cells.

In a serological follow-up of 88 women with active invasive cervical carcinoma, antibodies to membrane antigen of Herpes simplex virus (HSV)-infected cells were measured by the use of the mixed hemadsorption method. Sera were collected at the time of initial treatment and then at regular intervals. As controls, 85 healthy age-matched women and 70 patients suffering from other types of cancer were tested similarly. During the 6-to 60-month observation period 16 patients in the cervix carcinoma group died. The reactivity with membrane antigen of HSV-infected cells was positive in 71% of the cervical carcinoma patients, whereas the figure for the other cancer group was 27% and for the age-matched control group 27%. In the group of 16 patients who died, only 3 demonstrated antibodies against surface antigens of HSV-infected cells. In most cases radiation treatment of the tumor did not significantly alter the mixed hemadsorption titer but in 10 surviving patients there was a significant increase in reactivity as the tumor was treated; 1 patient who had recurrence of her cancer lost reactivity in later sera. Among the 11 cervix carcinoma patients in stage I (by clinical definition carcinoma strictly confined to the cervix) all but one showed positive reaction against the surface antigen of HSV-infected cells; the patient lacking reactivity was the only one out of the 11 patients in stage I who had a recurrence of her cancer. The results confirm that low or missing antibody titers to membrane antigen of HSV-infected cells are of prognostic significance, and decreasing antibody titers to membrane antigens run parallel to the severity of the lesions. There was poor correlation between antibody titers against membrane antigens and neutralizing antibody titers.

Determination of varicella immunity by the indirect immunofluorescence test in urgent clinical situations.

Certain categories of patients run an increased medical risk when exposed to varicella. Newborns lacking maternal immunity, immunosuppressed leukemic children or children with other immunodeficient disorders may gain a decisive benefit by administration of e.g. interferon or of specific immunoglobulin against varicella. An indirect immunofluorescence (IF) method has been used to estimate varicella. An indirect immunofluorescence (IF) method has been used to estimate varicella immunity. Of 51 heavily exposed women denying earlier varicella, 39 were found to be immune by the test and none of those contracted varicella, whereas 9 out of the 12 non-immune women fell ill. 14/48 immunosuppressed children were found to be seropositive and none of these contracted varicella, whereas 13 mild or subclinical cases occurred among the 34 seronegative children. The same test revealed that 175/182 (96%) young adults in Sweden were immune. The indirect IF test is considered a rapid, simple and reliable method for estimating varicella immunity.

Early diagnosis of virus-caused vesicular rashes by immunofluorescence on skin biopsies. II. Poxvirus (vaccinia).

Immunofluorescence (IF) was used to demonstrate vaccinia virus antigen in frozen sections of skin biopsies from the site of revaccination in 42 individuals. The immunoglobulin (Ig) of a rabbit anti-vaccinia serum and the Ig of the pre-immune serum conjugated with fluorescein-isothiocyanate (FITC) was employed. 11/13 biopsies taken 1 day after vaccination were positive in the IF test as were 13/13 biopsies taken 2 days and 14/16 biopsies taken 3 days after vaccination. Even minute quantities of virus antigen were easily detected. The applicability of the test and the advantage of using biopsy material in early rashes of vaccinia and variola is discussed. The reliability of the direct IF using conjugated antisera against vaccinia-variola, varicella-zoster and herpes simplex virus for differentiating between maculopapular rashes was proved in a coded test.