Differential antibody responses in 6.B major histocompatibility (B) complex congenic chickens

Effect of in ovo copper injection on body weight, immune response, blood biochemistry and carcass traits of broiler chicks at 35 days of age

The current study was conducted to investigate effects of copper (sulfate, acetate and nano) in ovo injection at 10 days of the embryogenesis period on body weight (BW), immunity, biochemical parameters and carcass traits of broiler chicks at 35 days of age. A total number of 462 fertile eggs were used in seven groups, each group containing 66 eggs in three replicates. The experimental design was as follows: the group 1 as a control, while groups 2, 3 and 4 injected with 8 μg/egg of Cu sulfate, Cu acetate and nano Cu, respectively, and groups 5, 6 and 7 injected with 16 μg/egg of Cu sulfate, Cu acetate and nano Cu, respectively. Results stated that BW was increased in Cu-injected groups, except groups of Cu acetate, but plasma constituents, carcass and relative weight of organs did not affect. Cu level (8 μg/egg) had better results than Cu level (16 μg/egg). No differences between among groups in relative weights of spleen and bursa and immune response. In conclusion, it is recommended that in ovo injection of different sources of Cu can augment the BW and did not harmfully affect immunity, carcass traits and biochemical parameters of broiler chicks.

Major histocompatibility complex recombinant R13 antibody response against bovine red blood cells

Recombination within the chicken major histocompatibility complex (MHC) has enabled more precise identification of genes controlling immune responses. Chicken MHC genes include BF, MHC class I; BL, MHC class II; and BG, MHC class IV that are closely linked on chromosome 16. A new recombination occurred during the 10th backcross generation to develop congenic lines on the inbred Line UCD 003 (B17B17) background. Recombinant R13 (BF17-BG23) was found in a single male chick from the Line 003.R1 (BF24-BG23) backcross. An additional backcross of this male to Line UCD 003 females increased the number of R13 individuals. Two trials tested this new recombinant for antibody production against the T cell-dependent antigen, bovine red blood cells. Fifty-one progeny segregating for R13R13 (n = 10), R13B17 (n = 26), and B17B17 (n = 15) genotypes were produced by a single R13B17 male mated to 5 R13B17 dams. One milliliter of 2.5% bovine red blood cell was injected intravenously into all genotypes at 4 and 11 wk of age to stimulate primary and secondary immune responses, respectively. Blood samples were collected 7 d after injection. Serum total and mercaptoethanol-resistant antibodies against bovine red blood cell were measured by microtiter methods. The least squares ANOVA used to evaluate all antibody titers included trial and B genotype as main effects. Significant means were separated by Fisher's protected least significant difference at P < 0.05. R13R13 chickens had significantly lower primary total and mercaptoethanol-resistant antibodies than did the R13B17 and B17B17 genotypes. Secondary total and mercaptoethanol-resistant antibodies were significantly lower in R13R13 chickens than in R13B17 but not B17B17 chickens. Gene differences generated through recombination impacted the antibody response of R13 compared with B17. Secondary antibody titers were not substantially higher than the primary titers suggesting that the memory response had waned in the 7-wk interval between injections. Overall, the results suggest that the lower antibody response in R13R13 homozygotes may be caused by recombination affecting a region that contributes to higher antibody response.

Bee pollen and propolis as dietary supplements for rabbit: Effect on reproductive performance of does and on immunological response of does and their offspring

To evaluate the effect of bee pollen (BP) and/or propolis (Pro) supplementation on rabbit does, 64 nulliparous NZW rabbits does were distributed among eight groups (eight animals/group). One unsupplemented group was the control; the other seven groups were supplemented, respectively, with zinc bacitracin (ZnB) at 100 mg, BP at 150 and 300 mg, Pro at 150 and 300 mg, BP+Pro at 150 and 300 mg of each three times/week, day after day continuously along eight parities. The BP300, Pro300 and BP+Pro150 groups had higher body weight of litter at birth and number of kids born alive. The BP supplementation at 150 mg increased plasma total protein and albumin than the control group. The BP or Pro at 150 mg decreased plasma T₃ than the other groups except for BP+Pro150. The ZnB group had significantly greater T₃ /T₄ ratio compared to BP, Pro and BP+Pro at 150 mg. The BP+Pro150 group had less ALT than the control; BP300 and Pro 300 mg resulted in lower plasma AST than the groups Pro150 with or without BP and the control group. The plasma alkaline phosphatase of BP at 150 or 300 mg and BP+Pro150 was significantly greater than that of the Pro150 group. The BP+Pro300 group had higher WBCs than the other groups. In contrast, the lymphocytes were greater in the Pro and BP+Pro300 groups than in BP, Pro and BP+Pro at 150 mg. The groups supplemented with BP and BP+Pro at 150 and 300 mg had significantly greater SRBCs of doe rabbits and their offspring compared to the control and the ZnB group. The BP at 300 mg increased the serum albumin and α₁ -globulin than the control group. The Pro300 group had greater serum α₂ -globulin and β-globulin than the control group. The total globulin was significantly greater for the 300 mg propolis-supplemented groups than the control.

MHC haplotype involvement in avian resistance to an ectoparasite

Research on immune function in evolutionary ecology has frequently focused on avian ectoparasites (e.g., mites and lice). However, host immunogenetics involved with bird resistance to ectoparasites has not been determined. The critical role of the major histocompatibility complex (MHC) in adaptive immunity and high genetic variation found within the MHC make this gene complex useful for exploring the immunogenetic basis for bird resistance to ectoparasites. The objective of this study was to determine if the avian MHC influenced resistance to a blood-feeding ectoparasite. Four congenic lines of chickens, differing only at the MHC, were comparatively infested with a cosmopolitan ectoparasite of birds-northern fowl mite (NFM)-which is also a serious pest species of poultry. Mite infestations were monitored over time and mite densities (weekly and maximum) were compared among lines. Chickens with the MHC haplotype B21 were relatively resistant to NFM, compared with birds in the B15 congenic line (P < 0.02). To test for similar effects in an outbred genetic background, a separate experiment was performed with 107 commercial chickens (white leghorn, W-36 strain) infested with NFM. Hens were genotyped using a MHC microsatellite marker (LEI0258) and associations between MHC haplotype and NFM density were tested. The highest peak NFM populations occurred more often on hens with the B15 haplotype versus the B21 haplotype (P = 0.012), which supported the results of the congenic study. These data indicate the avian MHC influences ectoparasite resistance, which is relevant to disease ecology and avian-ectoparasite interaction.

Alloantigen system L affects the outcome of rous sarcomas

This study was designed to examine the alloantigen system L effects on Rous sarcomas in three B complex genotypes. The parental stock was 50% Modified Wisconsin Line 3 x White Leghorn Line NIU 4 and 50% inbred Line 6.15-5. Pedigree matings of two B(2)B(5) L(1)L(2) sires to five B(2)B(5) L(1)L(2) dams per sire produced experimental chicks segregating for B and L genotypes. Chicks were inoculated with 20 pock-forming units (pfu) of Rous sarcoma virus (RSV) at 6 weeks of age. Tumors were scored six times over 10 weeks postinoculation after which the tumor scores were used to assign a tumor profile index (TPI) to each chicken. Tumor growth over time and TPI were evaluated by repeated-measures analysis of variance and analysis of variance, respectively. Six trials were conducted with a total of 151 chickens. The major histocompatibility (B) complex affected the responses as the B(2)B(2) and B(2)B(5) genotypes had significantly lower tumor growth over time and TPI than the B(5)B(5) genotype. Separate analyses revealed no significant L system effect in B(2)B(2) or B(2)B(5) backgrounds. However, L genotype significantly affected (P < 0.05) both tumor growth over time and TPI in B(5)B(5) chickens. B(5)B(5) L(1)L(2) birds had TPI significantly lower than B(5)B(5) L(1)L(1) chickens but not B(5)B(5) L(2)L(2). Mortality was lower in the B(5)B(5) L(1)L(2) birds than in B(5)B(5) L(2)L(2) chickens. The L system, or one closely linked, affects the growth and ultimate outcome of Rous sarcomas. The response may depend upon the genetic background as well as MHC type.

Antibody responses to sheep red blood cell and Brucella abortus antigens in a turkey line selected for increased body weight and its randombred control

Turkeys from a randombred control line (RBC2) and its subline (F) selected for increased 16-wk BW were tested for primary and secondary antibody responses to SRBC antigen and Brucella abortus antigen (BA). Previous studies have shown that the F line was more susceptible to Pasteurella multocida and Newcastle disease virus than was the RBC2 line. Individuals from the RBC2 and F lines were intravenously injected with 1 mL 5% SRBC antigen or 0.1 mL undiluted BA at 4 and 6 wk of age; blood samples were collected at 0, 4, 7, and 10 d post-immunization. Total, IgG, and IgM titers were measured by agglutination assays. Compared with the RBC2 line, the F line had generally higher total anti-SRBC titers; the differences were significant at 14 d postprimary immunization (PPI) (females); at 10 d postsecondary immunization (PSI) (males); and 4, 7, and 10 d PSI (females) (P < or = 0.05). The F line also had higher IgM titers at 14 d PPI (females) and at 10 d PSI (males) (P < or = 0.05). For IgG titers, a line difference was evident in females at 4 and 10 d PSI (P < or = 0.05); the F line had higher titers than did the RBC2 line. For the antibody response to BA in males, the F line had lower total and IgM titers at 10 d PPI (P < 0.05) than did the RBC2 line. No significant line differences in response to the BA were found in total and IgM titers in female turkeys or in IgG titers in both sexes at any time. These results suggest that selection for fast growth rate of turkeys might have resulted in changes in humoral immunity to the SRBC antigen and BA.

Analysis of MHC class II and class IV restriction fragment length polymorphism in chicken lines divergently selected for multitrait immune response

In the present study, chickens of four lines divergently selected for high (H) and low (L) immunocompetence in replicate were analyzed to investigate polymorphisms of MHC class II and MHC class IV on the molecular level associated with selection. The long-term selection experiment for multitrait immunocompetence was carried out in replicates and allows, therefore, the opportunity to distinguish effects of selection from other genetic factors. The SacI-digested DNA was hybridized individually with MHC class II and MHC class IV gene probes. The MHC class II RFLP analysis revealed four polymorphic bands and only one of them showed a significant difference between the selection directions H and L pooled between replicates. The small frequency differences of this band relative to the long-term selection suggest that this MHC class II fragment may contain genetic elements that are only slightly associated with the immune response traits used for selection. The hybridization with the MHC class IV probe displayed 26 scorable bands, of which 18 were polymorphic. In most instances, the differences between the lines were likely caused by the influence of genetic factors other than selection for multitrait immunocompetence. Only one band displayed a consistency in difference between selection directions in both replicates and no frequency difference between replicates. This band was almost completely absent in both H sublines, but at a frequency of about 50% in both L sublines. The general results of this study did not reveal major differences in band frequencies that indicate a close association of MHC class II and MHC class IV polymorphic markers to the divergent selection for multitrait immune response. Although the MHC makes a crucial contribution in immune response, it may have been difficult to detect single-gene associations with the selection criteria of this study, because of the myriad of components contributing to general immune responses measured in vivo.

Understanding immunology in disease development and control

Two functional aspects of the avian immune system, the humoral and the cell-mediated arms, provide the basis for the preventive and protective response against disease-causing microorganisms. On the other hand, certain avian diseases may induce a transient or permanent immunosuppressive state in one or both of these arms, leading to increased disease susceptibility. In addition to the classical immune response, manifested as antibody production or effector cell activation several cytokines and metabolites are also produced. The consequence of cytokine- and metabolite-mediated microenvironments may be either beneficial or result in a noninfectious immunopathology. Nevertheless, the integrity of the immune system and its functional modulation by factors such as genetics, nutrition, and prophylactic approaches continue to be an important focus of attention in current poultry research and production efforts.

Enhancement of humoral and cellular immunity by vitamin E after embryonic exposure

In the present study, the amnion of turkey and chicken embryos were injected 3 d prior to hatch with different levels of vitamin E (VE). In Experiments 1 and 2, turkey embryos received 10, 20, and 30 IU of VE. In Experiment 3, broiler embryos received 10 IU VE. In all three experiments, sham-injected control embryos (0 IU VE) received 300 microL of saline. In Experiments 1 and 2 (turkey embryos), 20 and 30 IU of VE reduced (P < or = 0.05) percentage hatchability below that of controls. At hatch, poults exhibited a dose related increase (P < 0.05) in plasma VE levels. Mean BW gain up to 35 d and relative bursa of Fabricius and spleen weights were not different among treatment groups. When challenged at 7 d posthatch, total (P < 0.05) and IgM (P < 0.08) anti-SRBC antibodies were higher in 10 IU VE poults than in controls. Immunoglobulin G levels did not differ among the treatment groups. Poults in the 10 IU VE group had higher (P < 0.002) numbers of Sephadex-elicited inflammatory exudate cells, as well as a greater percentage of phagocytic macrophages (P < 0.0001). Additionally, the numbers of SRBC per phagocytic macrophage were greater (P < 0.001), than in control poults at 4 wk of age. In Experiment 3, chick embryos exposed to 10 IU VE, exhibited no differences in hatchability, BW gain, or bursal and splenic weights from the sham-exposed group. However, total and IgM antibody responses against SRBC were greater (P < 0.01) in the 10 IU VE group at 7 d postinjection. A secondary SRBC challenge given at 14 d after primary injection resulted in higher total (P < 0.07) and IgG (P < 0.04) antibody responses in the 10 IU VE chicks than in the controls. Similarly, broiler chicks (10 IU VE) had more Sephadex-elicited abdominal exudate cells (P < 0.07), and greater macrophage phagocytic potential (P < 0.0001). In ovo VE exposure (10 IU) also increased nitrite production (P < 0.04) by chick macrophages. The results from this study demonstrated an enhanced antibody and macrophage response and suggest that in ovo exposure with VE may improve posthatch poult and broiler quality.