Haemolytic Complement Activity and Humoral Immune Responses to Sheep Red Blood Cells in Indigenous Chickens and in Eight German Dahlem Red Chicken Lines with Different Combinations of Major Genes (dwarf,naked neck and frizzled) of Tropical Interest

A total of 376 chickens from different ecotypes were immunized with the non-pathogenic multi-determinant antigen sheep red blood cells (SRBC). The ecotypes included indigenous chickens from various locations in Tanzania (n=102), India (n=86) and Bolivia (n=89). In addition, eight German Dahlem Red (GDR) chicken lines with different major genes (dwarf, naked neck and frizzled) of tropical interest were also immunized with SRBC. Immune competence of the breeds was assessed by measuring complement haemolytic activity, both from the classical calcium-dependent complement pathway (CPW) and alternative calcium-independent complement pathway (APW), alongside IgTotal, IgG and IgM antibody responses to SRBC at 7 days post immunization. Large variations in complement activity and antibody responses to SRBC were observed within and between the indigenous breeds. Many indigenous chickens, especially from Bolivia, showed decreased complement activity (APW) following immunization with SRBC. Breeds from India showed the highest CPW activity and humoral (especially IgM) responses to SRBC, suggesting high immune competence. In contrast, Bolivian chickens were characterized by low CPW activity, low APW activity and low antibody levels to SRBC suggesting an overall low immune competence. In the GDR chickens, characterized by high CPW activity and high IgG antibody responses to SRBC, the major genes for naked neck, frizzling and dwarfism had no significant effect on the antibody responses and complement activity to SRBC.     

Haemolytic complement activity,C3 and Factor B consumption in serum from chickens divergently selected for antibody responses to sheep red blood cells

Antibody responses, serum complement haemolytic activity, and complement component C3 and Factor B consumption were studied in chickens divergently selected for high and low antibody responses to sheep red blood cells, and in a randombred control line. Significantly higher total and IgG antibody responses to SRBC were found after intramuscular immunisation in the high antibody responder (H) line versus the low antibody responder (L) line and the control (C) line. Also significantly higher antibody titres were found in the C line as compared to the L line. Ca-dependent (classical) and Ca-independent (alternative) complement haemolytic activity was significantly higher in the H line than in the L line. Also initial complement haemolytic activity and C3 levels prior to immunisation with SRBC were significantly higher in the H than in the L line. The L line, on the other hand, showed numerically higher Factor B levels. Immunisation with SRBC was followed by a different consumption of C3 in serum of the H line than the L line.The results indicated that divergent selection of chickens for specific antibody responses to SRBC affected complement levels and C3 consumption in these chickens. This suggests a genetic linkage between these two immune traits.     

Interactions of dietary polyunsaturated fatty acids and vitamin E with regard to vitamin E status,fat composition and antibody responsiveness in layer hens

1. Effects of dietary polyunsaturated fatty acids (PUFA) and vitamin E (VE) on an immune response may interact because VE may protect PUFA from in vivo oxidation. The present study was designed to study the presence of such an interaction in growing layer chickens. 2. Three dietary concentration of linoleic acid (LA, 3.3, 6.6 and 10%), in combination with 4 concentration of dietary VE (5, 20, 40 and 80 mg/kg) were used. Effects of LA and VE on circulating VE concentration, fatty acid composition of bursal and adipose fat, and antibody kinetics against keyhole limpet hemocyanin and Mycobacterim butyricum were established. 3. At high dietary LA concentration, bursal and adipose LA were higher but bursal arachidonic acid and long chain n-3 PUFA decreased. The dietary VE level did not consistently affect the deposition of PUFA in tissue. Plasma VE concentrations were affected by the dietary VE and LA content, but not by their interaction. Antibody responses before and 7 d after immunisation were affected by the dietary treatments. Antibody concentration were not affected by tissue fatty acid content. 4. In conclusion, the interaction effects of dietary PUFA and VE on fat deposition and immune responses are of minor importance compared to separate PUFA and VE effects. This implies that, within the studied range, adding extra VE to preserve or affect the effects of dietary PUFA on antibody responsiveness is unnecessary.     

Effect of vitamin E and fat source in sows' diets on immune response of suckling and weaned piglets

Thirty-six 7-mo-old gilts were used to study the effects of dietary vitamin E and fat source (5% sunflower oil or animal fat) in pregnant and lactating sow diets on serum vitamin E concentration and on cell-mediated and humoral immune response in suckling and weaned piglets. Six gilts each received one of six diets throughout pregnancy and lactation. The basal diets (13 mg alpha-tocopherol/kg diet) were supplemented with dl-alpha-tocopheryl acetate to 48 and 136 mg alpha-tocopherol/kg of feed (average analyzed values). After weaning (at 4 wk of age) all pigs received identical diets (20 mg of alpha-tocopherol/kg feed). One week after weaning, pigs were immunized (i.m. with ovalbumin and tetanus toxoid) and antibody production was measured. Blood samples were taken immediately after birth, at 1 wk after birth, at weaning, and at four weekly intervals after weaning. Samples were analyzed for alpha-tocopherol concentration, total number of leukocytes, T- and B-lymphocytes, lymphocyte stimulation with concanavalin A, lysozyme activity, and immunoglobulin concentrations. It was concluded that a high vitamin E level in the sow's diet increased serum vitamin E concentration of 1-wk-old pigs (P less than .05). Immune response against ovalbumin was increased (P less than .05) at 1 wk of age after immunization for weaned pigs from sows fed the high level of vitamin E. Also, the phagocytic measures of pigs at 1 wk of age were increased by the medium vitamin E level (P less than .05). Fat sources in the sow's diet had no consistent effect on the immunological measures of pigs.     

Natural (auto)antibodies in calves are affected by age and diet

Background: Natural autoantibodies (N(a)ab) were found in every species tested so far, and are likely important in maintaining homeostasis.

Objectives: (1) To determine N(a)ab in Bos taurus calves, (2) evaluate effects of diet and age on N(a)ab binding repertoires in calves, and (3) delineate bovine liver cell lysate (BLL) antigens related with variation in rumen score and body weight.

Animals and methods: Effects of age and diet on staining of BLL fragments by IgM and IgG antibodies in serum samples collected at 20 or at 26 weeks of age from bull calves either fed a restricted or ad libitum diet were analyzed using quantitative Western blotting. Correlations between fragments stained and grouping of calves were done by Principal Component Analysis (PCA). Redundancy analysis (RDA) was done to relate rumen score and body weight variation at slaughter at 27 weeks of age with stained BLL fragments.

Results: In sera from all calves IgM and IgG antibodies binding BLL antigens were found. Corresponding fragments were stained, but quantitative differences in staining intensities were related to diet and age for both IgM and IgG. PCA revealed that age had a greater influence than diet on BLL fragment staining. RDA suggested that staining by IgM or IgG of specific BLL fragments was related with variation in rumen score and body weight.

Conclusions and clinical importance: Analyses of N(a)ab in serum could be a potential tool to estimate the health status of cattle, and be used to evaluate effects of husbandry practices.     

Serological Screening for MHC (B)-Polymorphism in Indigenous Chickens

As part of a series of studies to characterize innate and specific immune responses of indigenous chicken lines, birds from Bolivia and India were screened serologically for MHC class IV (BG) polymorphism by direct haemagglutination using haplotype-specific antisera (B2, B4, B12, B13, B14, B15, B19, B21). The sample consisted of 95 Bolivian indigenous chickens and 119 hens from the four most common North Indian 'back-yard' chicken lines: Yellow Aseel (AP), Kadaknath (KN), frizzled typed (Ff-) and naked neck (NN). Of all chickens tested, the majority were haplotyped as B2, B15, B19 and B21. Of the Bolivian chickens, 89.5% could be haplotyped: 54.9% were homozygous (including 43.3% B15), and 34.6% were heterozygous (including 15.7% B15). B2-like haplotypes were not found among the Bolivian hens, and only 3.2% of these birds showed homozygous B21-like proteins. Of the Indian hens, MHC (BG)-like proteins could be detected in 60.0% of the AP birds, 6.7% of the KN birds; 40.0% of the Ff- birds; and 10.3% of the NN birds. In these lines, a total of 40.1% (AP), 6.7% (KN), 30.1% (Ff-) and 10.3% (NN) were homozygous for the B-haplotype. Only in the AP line (19.9%), and the Ff- line (9.9%) were heterozygous B-haplotypes types found. The B2 haplotype was found in all Indian chicken lines. Most Indian birds have completely unknown haplotypes, indicating a potentially interesting genetic pool. Subgrouping the Bolivian and Indian indigenous hens into monomorphic BG populations revealed individual differences based on the B-types.     

Different sources of dietary n-6 polyunsaturated fatty acids and their effects on antibody responses in chickens

1. Effects of linoleic and linolenic acid provided via different oil sources on total antibody (Ab) titres, Ab isotypes after primary and secondary immunisation, and cutaneous hypersensitivity (CH) responses to bovine serum albumin (BSA) and maleyl-BSA, respectively, were studied in pullets fed on one of 4 diets. The diets were the basal control diet enriched with either sunflower oil or safflower oil as sources of linoleic acid, and linseed oil as a source of linolenic acid, tested against a control diet supplemented with animal fat. 2. Total Ab and immunoglobulin (Ig) isotype responses to BSA were affected by diet after primary, and diet x immunisation effects after secondary immunisation. Higher total Ab and IgG titres to BSA were found especially after primary immunisation in birds given the sunflower oil enriched diet, whereas birds given sunflower oil mounted significantly lower IgM titres to BSA after primary and secondary immunisation. The antibody responses to maleyl-BSA were affected by diet after primary, and immunisation x diet interactions after secondary immunisation. Sunflower oil enhanced total and IgG Ab titres to maleyl-BSA after primary immunisation, but decreased IgM titres to maleyl-BSA after primary and secondary immunisation. Cutaneous hypersensitivity responses to BSA and maleyl-BSA were not affected by the diet. 3. It is concluded that modulation of the magnitude and isotype of Ab responses of poultry to T cell-dependent antigens is affected not only by type of essential fatty acids, but also by their source. In the present study the n-6 source, sunflower oil, showed strong enhancement of primary Ab responses, directed to both Th2 and Th1 antigens. On the other hand, the different effects of safflower oil imply that constituents other than n-6 acids within dietary plant oils may affect immune responsiveness. 4. The relationship between magnitude and isotype of Ab responsiveness, type of antigen, and essential fatty acids is discussed.     

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.