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Biomedical subjects

A J van der Zijpp

Publications and source records attributed to A J van der Zijpp.

At least 19 recordsLinked to original sources
PubMed1995

Phagocytic activity of two lines of chickens divergently selected for antibody production.

Differences in phagocytic capacity of two chicken lines selected for high (H) or low (L) antibody response against sheep red blood cells (SRBC) were studied in 8 month old cocks of the seventh selection generation. The H line cocks had significantly higher agglutinin titers after immunization with SRBC than the L line. The total clearance capacity of the phagocytes, measured by the clearance of carbon particles from the blood, did not differ between the lines. The L line cocks had more circulating granulocytes. However, the granulocytes of the H line phagocytized more yeast cells than those of the L line. Neither in immunized nor in non-immunized cocks, were line differences found in the intracellular destruction of antigen by phagocytes, estimated as the superoxide production during phagocytosis and the plasma levels of lysozyme activity and acid phosphatase, before and after immunization. It was concluded that the line difference in antibody response was not due to measurable differences in phagocytic activity.

Acid Phosphatase↗
PubMed1993

Mapping of susceptibility to Marek's disease within the major histocompatibility (B) complex by refined typing of White Leghorn chickens.

The major histocompatibility (B) complex of a distinct commercial pure White Leghorn chicken line was characterized using serological, biochemical and restriction fragment length polymorphism (RFLP) typing. Line B chickens displayed a high recombination frequency within the B complex. Three recombinant haplotypes were identified. The influence of these haplotypes was determined in relation to the haplotypes B19 and B21 on their resistance to Marek's disease (MD) in an experimental infection with the virus. Offspring of sires with a recombinant haplotype in combination with B19 or B21, and dams, which were homozygous B19/B19 or B21/B21 were infected. The B type of the offspring had a significant effect upon survival. Animals with B complex types B21/B21, B134/B21 and B234/B21 were relatively resistant to MD (24-32% mortality), whereas B19/B19 birds were highly susceptible (68% mortality). Animals with a recombinant haplotype B19r21 (B-G21, B-F19) were equally susceptible to MD as birds with the complete B19 haplotype. In contrast to earlier publications, resistance was not inherited as a dominant trait. Apparently, B19 was associated with a dominant susceptibility. The gene(s) associated with the B complex and involved in resistance to MD were localized within the B-F/B-L region. However, the association with a presumably non-coding subregion of B-G could not be excluded.

Animals↗
PubMed1993

Effect of divergent selection for immune responsiveness and of major histocompatibility complex on resistance to Marek's disease in chickens.

Lines of chickens selected for nine generations for high (H) or low (L) antibody response to SRBC, a randombred control (C) line, and an F1 cross between H and L lines were challenged for resistance to Marek's disease (MD). Hens only were challenged at day-old by contact with virulent MD Strain K. Birds were serologically typed for MHC erythrocyte antigens. Chicks from the L and H lines died earlier and later, respectively, than the C chicks, whereas time of death did not differ between F1 birds and the L chicks. Mortality in the L line (70.1%) was higher than in the C line (42.8%), but mortality in the H line (40.9%) was not lower than in the C line or the F1 cross (47.5%). Effects of MHC genotypes and haplotypes on mortality from MD were estimated within lines with a logistic regression model. Effect of MHC was moderate in the H line (P < .10) and highly significant in the C line (P < .005). Effects of MHC genotypes were similar in the H and C line but differed in the L and F1. Heritability of mortality from MD estimated with a threshold model including relationships between individuals was .40 when all lines were grouped together, whereas heritability estimated for each line separately was .45, .51, and .78 in the H, C, and L lines, respectively. Correlations between estimated breeding values for antibody response to SRBC and mortality from MD varied between lines and sexes. Correlations also were affected by whether or not the MHC effect was taken into account.

Animals↗
PubMed1992

Effects of route of immunization, adjuvant and unrelated antigens on the humoral immune response in lines of chickens selected for antibody production against sheep erythrocytes.

Effects of intramuscular (i.m.), intravenous (i.v.) and intraperitoneal (i.p.) primary immunization with the T-dependent antigen, sheep red blood cells (SRBC), was studied in two chicken lines selected for either high (H) or low (L) antibody response after i.m. immunization with SRBC. The primary route of immunization affected the line differences in the primary response and in the secondary response after i.m. reimmunization. Intravenous immunization with the T-dependent antigen bovine serum albumin (BSA) showed line differences similar to those found after i.m. or i.v. immunization with SRBC. Immunization with both the partially T-independent antigens Brucella abortus (BA) or Salmonella H-antigen (SHA) revealed no line effect. Immunization with SRBC in incomplete Freund's adjuvant (IFA) did not change the difference between lines, whereas immunization with complete Freund's adjuvant (CFA) diminished the difference between lines. It is postulated that differences in antibody production between the selected lines might be attributed to differences in T-cell activity.

Animals↗
PubMed1992

Production of chickens with marginal vitamin A deficiency.

Marginally vitamin A-deficient 1-d-old chickens capable of remaining healthy for at least 6 weeks were produced using a two-generation model. In this model, hens fed on diets with a limited vitamin A content were used to obtain 1-d-old chickens which were marginally deficient in vitamin A. Only hens with a narrow range of plasma retinol values (0.60-0.85 mumol/l) were satisfactory for this purpose. Above this range the 1-d-old chickens were not marginally vitamin A deficient. Below this range egg production and hatchability were affected to some extent depending on the degree of vitamin A deficiency. Even when egg production and hatchability remained at a high level in such birds, the 1-d-old chickens produced were not sufficiently strong to survive the first weeks of life. The advantages of the two-generation model for producing marginally vitamin A-deficient chickens are the increased uniformity and predictability of the chickens with respect to body-weight, general health and vitamin A status. However, it does take about 3 months to produce such chickens.

Animals↗
PubMed1992

Epithelia-damaging virus infections affect vitamin A status in chickens.

The effect of infection with infectious bronchitis virus (IBV) and reovirus (RV) on vitamin A status was investigated in chickens with a normal or marginal intake of vitamin A. At the age of 4 wk, chickens were infected with either IBV or RV, primarily affecting the respiratory or intestinal tract, respectively. Both viruses lowered plasma retinol levels significantly. The effect was more pronounced in chickens fed a diet marginally deficient in vitamin A than in those fed a diet adequate in vitamin A. Concentrations of retinol-binding protein, transthyretin and albumin in RV-infected chickens were also significantly lower than in noninfected chickens fed the same diets; in chickens infected with IBV, there was no effect. These results suggest that the reduced vitamin A status of IBV-infected chickens could be attributed to increased rate of utilization by tissues. In RV infection, this mechanism could be involved but impaired absorption of nutrients (including vitamin A) and direct loss of nutrients via the intestinal tract could also be important.

Animals↗
PubMed1992

Divergent selection for immune responsiveness in chickens: estimation of realized heritability with an animal model.

With the aim of improving general disease resistance, chickens were divergently selected for their antibody titers 5 d after immunization with sheep red blood cells for nine generations. Selected and control lines differed significantly for primary and secondary responses after three generations. Heritability of the antibody titer was estimated by REML fitting an animal model using a derivative-free algorithm. The heritability estimate using data on all lines simultaneously was .31. Realized heritability of the antibody titer in the selected lines was estimated by using either the phenotypic cumulative response as the deviation from the control line or the mean breeding values obtained with an animal model. Values from the two methods were consistent, giving a realized heritability of .21 and .25 in the high and low lines, respectively. The genetic trend was not linear and the response to selection tended to accelerate over generations.

Animals↗
PubMed1991

Changes in lymphoid organs and blood lymphocytes induced by vitamin A deficiency and Newcastle disease virus infection in chickens.

The effect of vitamin A deficiency in the presence or absence of Newcastle disease virus infection (NDV, La Sota strain) on weight of lymphoid organs and on the number and type of circulating white blood cells (WBC) was investigated in chickens. Day-old chickens with limited vitamin A reserves were fed purified diets containing either marginal (ad libitum) or adequate (pair-fed) levels of vitamin A and at 21-28 days of age; half the chickens in each group were infected with NDV. Vitamin A deficiency resulted only in significantly lower absolute and relative weights of bursa of Fabricius and after infection both weights of bursa and thymus were significantly lower. Relative weight of spleen was significantly higher after infection irrespective of vitamin A status. Liver weights were not affected by vitamin A status and/or NDV infection. Both vitamin A deficiency and NDV infection resulted in lymphopenia, while the lowest number of WBC were observed in vitamin A-deficient chickens during the acute phase of NDV (5 days after infection). Subsequent to lymphopenia due to NDV infection, a marked lymphocytosis was observed in controls and to a lesser extent in vitamin A-deficient birds. These results indicate that vitamin A deficiency, which is aggravated by concomitant NDV infection, affects lymphoid cell systems.

Animals↗
PubMed1991

Effect of vitamin A deficiency on the activity of macrophages in Newcastle disease virus-infected chickens.

The effect of vitamin A deficiency on the activity of peritoneal macrophages (PM) was investigated in noninfected and Newcastle disease virus (NDV)-infected chickens. Day-old chickens with limited vitamin A reserves were fed diets containing either marginal (120 retinol equivalents (RE)/kg) or adequate (1200 RE/kg) levels of vitamin A. At 4 weeks of age, half of the chickens in each group were infected with the La Sota strain of NDV and PM were isolated 11 or 12 days later. These were used for counting the uptake of fluorescein isothiocyanate-labeled yeast cells as an indicator of phagocytic activity and for measuring the reduction of nitroblue tetrazolium (NBT), which provides an estimate of oxygen-dependent killing of microorganisms. Vitamin A deficiency impaired NBT reduction and, to a lesser extent, phagocytosis in both infected and noninfected chickens. NDV infection increased phagocytosis and NBT reduction in normal and, to a lesser extent, in vitamin A-deficient chickens.

Animals↗
PubMed1990

[Genetic manipulation in farm animals: how and why?].

A review of the history of the knowledge of the development of DNA was presented on the symposium 'Biotechnology'. Entirely in agreement with expectations, genetic manipulation became suitable for use, also in farm animals, approximately thirty years after the discovery of the double helix. The technology available for transfection is limited and is only successful in a small number of cases: less than one per cent. In addition, gene constructions give rise to a large number of problems as they are not tissue-specific and fail to function at the correct time in the course of development. The knowledge of interesting genes (at DNA level) in farm animals is of vital importance. Detecting these genes will undoubtedly still require considerable effort. In view of the technical state of things, medical and physiological studies using transfection will obviously have to provide a new insight prior to use. This is in agreement with the memorandum on 'Ethics and Biotechnology in Animals'. A 'no, unless' procedure is recommended in this note, room being left for 'good' objectives of research following ethical consideration.

Animals↗
PubMed1990

Vitamin A deficiency impairs cytotoxic T lymphocyte activity in Newcastle disease virus-infected chickens.

The effect of vitamin A deficiency on cytotoxic T lymphocyte (CTL) activity was investigated during the acute phase of disease 7 days after primary inoculation and 1 day after secondary inoculation in chickens with or without Newcastle disease virus (NDV, La Sota strain) infection. Day-old chickens with limited vitamin A reserves were fed purified diets containing either marginal (ad libitum) or adequate (pair-fed) levels of vitamin A, and at 3 weeks of age half of the chickens in each group were infected with NDV. Cytotoxic activity was investigated during the acute phase of disease (7 days after primary inoculation) and 1 day after secondary inoculation, in an assay system with either peripheral blood lymphocytes (PBL) or nonadherent splenocytes as effector cells and adherent splenocytes from the same animal as target cells. After primary inoculation, cytotoxic activity could only be demonstrated in nonadherent splenocytes. Vitamin A deficiency resulted in significantly reduced CTL activity at all effector/target cell ratios tested. After reinfection CTL activity could also be demonstrated in PBL, but only from chickens fed the control diet, suggesting a diminished pool of CTL in vitamin A deficiency. The results of this study indicate that vitamin A deficiency impairs CTL activity - a part of the cell-mediated defense system - and this may have important implications for recovery from viral infection.

Animals↗
PubMed1990

Heat-stress influences on antibody production in chicken lines selected for high and low immune responsiveness.

The effect of heat stress on antibody production to sheep red blood cells (SRBC) was investigated during three experiments using chicken lines selected over six generations for high (H) or low (L) plasma-antibody titer to SRBC after primary intramuscular immunization. The chickens were immunized 24 h after a heat-stress treatment (HS) of four periods of 30 min each at a temperature of 42 C with an intervening 30-min period at a temperature of 22 C. For the control treatment (CT), the chicks were handled the same, but at a temperature of 22 C. Antibody titers were measured on 3, 5, 7, 10, and 14 days postimmunization. The intramuscular immunizations, .25 mL of SRBC, were given in all three experiments; an additional intravenous immunization of .5 mL of 14% SRBC was given in Experiment 2 and of .5 mL of 5% SRBC in Experiment 3. A significant effect of the HS treatment on antibody titers (P less than .05 on Days 3, 5, 7, and 10 after immunization) was found only in Experiment 1. The titers decreased in the H line only. The differences between the H and L lines were significant (P less than .001) in all three experiments after both the intramuscular and the intravenous immunizations. Heat stress was found to have little or no effect on antibody production in the lines studied in the present experiments.

Animals↗
PubMed1990

Effect of different doses of sheep erythrocytes on the humoral immune response of chicken lines selected for high or low antibody production.

A study was conducted to determine the influence caused by the dose of sheep red blood cells (SRBC) on the humoral response of chicken lines selected for high (H) or low (L) antibody production to SRBC. The chicks were of the 5th selection generation. Both sexes were used. The primary doses of SRBC used were: 5 x 10(-4), 5 x 10(-3), 5 x 10(-2), 25 x 10(-2), and 5 x 10(-1) mL packed cells, suspended with phosphate-buffered saline (PBS) to 1 mL, and injected intramuscularly (im). All chicks were reimmunized im with 5 x 10(-1) mL packed cells in 1 mL of PBS. Throughout the experiment, H line chicks had higher titers than L line chicks. The level of primary total and 2-mercaptoethanol (2ME)-resistant titers followed the dose level. However, in total titers, the interactions between line and dose were seen at days 3 and 5 postimmunization. This was caused by a deviation in the ranking of the doses in the L line. Moreover, the kinetics of the primary response differed between the lines. Generally, in H line the peak number for the titers was reached earlier in the response period. The optimum response in terms of the total number of titers in the secondary response generally was inverse to the primary dose level. However, from Day 7 of the secondary response onward, the dose effects were influenced by line. For Line L, no effects for dose on the responding antibody level was seen. The 2ME-resistant titers followed the dose level in the secondary response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The major histocompatibility complex and diseases in farm animals.

Breeding for genetic resistance to disease and development of veterinary vaccines are major stimuli for research of the major histocompatibility complex (MHC) in farm animals. Genetically determined resistance is an attractive preventive measure because it precludes veterinary services, and is consistent over generations. Also many infectious diseases in farm animals cannot be prevented by vaccination. In a recent seminar sponsored by the European Community, the MHC of farm animals was discussed, its association with diseases was assessed, and other means of selection for disease resistance were evaluated.

Animal Diseases↗
PubMed1988

[Biotechnology for the improvement of disease resistance].

Although satisfactory results in regard to genetic resistance may be obtained by classical breeding methods (selection and cross-breeding), there are considerable drawbacks to these techniques because of the number of generations of selection and the cost of challenge tests. Using the present knowledge of the immunology and pathology of Marek's disease, the genetic basis and the association with the B locus (the Major Histocompatibility Complex in chicken), it is possible to improve genetic resistance to Marek's by biotechnological methods today. The hybridisation technique and DNA studies will be helpful in rapidly tracing resistant birds. Resistant genes may be isolated by DNA studies and transferred to birds in which these genes are absent. The birds which came into possession of these genes have the advantage that other, undesirable genetic material was not transmitted by cross-breeding. The example provided by the use of biotechnological techniques in Marek's disease may also serve for other forms of disease and other farm animals.

Animals↗
PubMed1987

[Genetic aspects of disease resistance in farm animals].

Improved hygiene, management and vaccinations have led to reduced natural selection, which means that breeding farms have less information on the disease resistance status of their breeding stock. Knowledge concerning the mechanisms of resistance (immunology) has increased enormously. In diseases for which preventive measures are not available, genetic resistance may be of importance. This requires knowledge of parameters involved in disease resistance, and their genetic background. This article discusses the genetic resistance of specific diseases, and general disease resistance, in poultry, pigs and cattle.

Animals↗