Abdelrahman S, Chandrasekaran A. Live performance, nutrient digestibility, immune response and fecal microbial load modulation in Japanese quails fed a Bacillus-based probiotic alone or combination with xylanase

Animal industry seeks cost-effective solutions to enhance performance and health of domestic animals. This study investigated the effects of supplementing Bacillus spp. probiotics and xylanase on 2000 one-day-old Japanese quails, randomly assigned to four treatment groups (10 replicates). The control group received no supplementation, while the others were supplemented with a Bacillus-based probiotic at 7.5 × 107 cfu/kg of feed, xylanase enzyme (2,000 U/kg) alone or in combination. Quails receiving both probiotic and enzyme exhibited significantly (p < 0.01) higher weekly and overall weight gain, and lower feed conversion ratios compared to the control group. Dressing percentage was higher (p < 0.01), and mortality lower in birds supplemented with a combination of enzyme and probiotic. Antibody titres against infectious bronchitis and infectious bursal disease were significantly (p < 0.01) higher in quails receiving combined probiotic and enzyme supplementation, while titres against Newcastle disease virus were higher (p < 0.01) in groups supplemented with probiotic and enzyme individually or in combination. Additionally, digestibility was significantly (p < 0.01) higher in groups receiving combined enzyme and probiotic supplementation, with higher apparent metabolizable energy compared to the control. The populations of beneficial Lactobacillus increased, while harmful E. coli and Salmonella decreased significantly in quails supplemented with both probiotic and enzyme. In conclusion, supplementing xylanase enzyme and probiotic together in Japanese quails positively influenced growth, nutrient digestibility, immune response, and cecal microbiota.

Polystyrene microplastics disrupted physical barriers, microbiota composition and immune responses in the cecum of developmental Japanese quails

Microplastics, a new type of emerging pollutant, is ubiquitous in terrestrial and water environments. Microplastics have become a growing concern due to their impacts on the environment, animal, and human health. Birds also suffer from microplastics contamination. In this study, we examined the toxic effects of polystyrene microplastics (PS-MPs) exposure on physical barrier, microbial community, and immune function in the cecum of a model bird species-Japanese quail (Coturnix japonica). The one-week-old birds were fed on environmentally relevant concentrations of 20 µg/kg, 400 µg/kg, and 8 mg/kg PS-MPs in the diet for 5 weeks. The results showed that microplastics could cause microstructural damages characterized by lamina propria damage and epithelial cell vacuolation and ultrastructural injuries including microvilli breakage and disarrangement as well as mitochondrial vacuolation in the cecum of quails. In particular, blurry tight junctions, wider desmosomes spacing, and gene expression alteration indicated cecal tight junction malfunction. Moreover, mucous layer breakdown and mucin decrease indicated that chemical barrier was disturbed by PS-MPs. PS-MPs also changed cecal microbial diversity. In addition, structural deformation of cecal tonsils and increasing proinflammatory cytokines suggested cecal immune disorder and inflammation responses by PS-MPs exposure. Our results suggested that microplastics negatively affected digestive system and might pose great health risks to terrestrial birds.

Dietary supplementation with Dunaliella salina microalga promotes quail growth by altering lipid profile and immunity

The goals of the current research are to ascertain the impacts of Dunaliella salina (DS) on quail growth, carcass criteria, liver and kidney functions, lipid profile, and immune response. Two hundred and forty 7-day-old quail chicks were divided equally into 4 separate groups with 6 replicates with 10 birds each. The groups were as follows: 1) control diet (the basal feed without DS), 2) control diet enriched with 0.25 g DS/kg, 3) control diet enriched with 0.50 g DS/kg, and 4) control diet enriched with 1.00 g DS/kg. Results elucidated that the birds which consumed 0.5 and 1 g DS/kg diet performed better than other birds in terms of live body weight (LBW), body weight gain (BWG), and feed conversion ratio (FCR). There were no significant changes in feed intake (FI) and carcass characteristics due to different dietary DS levels. Compared to the control group, DS-treated groups had better lipid profile (low total cholesterol and LDL values and high HDL values) and immune response (complement 3 values). The quails consumed feeds with different levels of DS had greater (P < 0.038) C3 compared to control. Adding 0.5 and 1 g DS/kg lowered blood concentrations of triglycerides and total protein (TP) values. The high level of DS (1 g/kg) had higher albumin values and lower AST values than other groups (P < 0.05). The creatinine values were at the lowest levels in the group consumed 0.50 g DS/kg feed. No changes (P > 0.05) were demonstrated among experimental groups in the ALT, urea, and lysozyme values. In conclusion, adding D. salina to growing quail diets enhanced growth, immune system, blood lipid profile, and kidney and liver function.

Effect of omega-3 rich diet on the response of Japanese quails (Coturnix coturnix japonica) infected with Newcastle disease virus or avian influenza virus H9N2

This study was performed to evaluate the effects of omega-3 supplementation on growth performance, clinical signs, post-mortem lesions, haemagglutination inhibition (HI) antibody titres, gene expression and histopathology in quails (Coturnix coturnix japonica) infected with Newcastle disease virus (NDV) and avian influenza virus (AIV) H9N2. One hundred, 40-day-old male quails were divided into 5 groups: G1, fed a control basal diet; G2A, infected with NDV; G2B, infected with H9N2; G3A, infected with NDV and given omega-3, and G3B, infected with H9N2 and given omega-3. The dietary omega-3 supplementation was continued for 4 weeks: two weeks before infection and two weeks after intranasal infection with virulent NDV and AIV H9N2. Our results revealed significant differences (P < 0.05) in growth performance, HI antibody titres, clinical signs, post-mortem lesions, mortality, viral shedding rates, immunological parameters, and histopathological lesions between the treated (G3A and G3B) and untreated (G2A and G2B) groups. In conclusion, dietary omega-3 supplementation for 4 weeks can improve growth performance and alleviate the deleterious immunological and pathological effects of NDV and AIV H9N2 infection in quails.

Chronic lead exposure induces histopathological damage, microbiota dysbiosis and immune disorder in the cecum of female Japanese quails (Coturnix japonica)

Lead (Pb) is one of the most hazardous metals to human and wildlife and it also has multiple negative impacts on birds. However, its influences on bird gut morphology and intestinal microbiota were still unclear. We used female Japanese quails (Coturnix japonica) to examine the effects of chronic lead exposure (0, 50 ppm and 1000 ppm) on cecal histology, microbial communities and immune function. The results showed 50 ppm lead exposure caused subtle damages of cecum cell structure. However, 1000 ppm lead exposure caused severe cecum histopathological changes characterized by mucosa abscission, Lieberkühn glands destruction and lymphocyte proliferation. Moreover, both lead concentrations induced ultrastructural damages featured by nucleus pyknosis, mitochondrial vacuolation and microvilli contraction. Meanwhile, microbial community structure, species diversity, taxonomic compositions and taxa abundance in the cecum were affected by lead exposure. Furthermore, the mRNA relative expression of immunity-related genes such as interleukin 2 (IL-2) and gamma interferon (IFN-γ) was significantly downregulated while that of interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and natural killer kappa B (NF-κB) was significantly upregulated in the cecum of 50 and 1000 ppm lead exposure groups. We concluded that lead exposure may cause gut health impairment of female Japanese quails by inducing cecal histopathological changes, microbiota dysbiosis and cecal immune disorder.

Exposure of Avian Embryos to Cycling Incubation Temperatures Reduces Adult Bactericidal Ability

In birds, the temperature at which eggs are incubated shapes many aspects of hatchling phenotype, but long-term effects are less studied. We studied the effect of incubation temperature and pattern on the subsequent development of innate immune function in Japanese quail (Coturnix japonica). We incubated quail eggs in one of three replicated treatments: control (37.5°C), low (36.0°C), and cyclical incubation. The cyclical treatment had the same average temperature as the low-temperature treatment (36.0°C) and an upper temperature that was the same as the control. When individuals were 5, 20, and 55 d of age (i.e., adults), we measured the ability of blood plasma to kill Escherichia coli. Throughout development there was a nonsignificant trend for immune function to be lower in the cycling treatment. In adulthood, however, individuals incubated at cycling temperatures had significantly lower immune function than control birds but did not differ from individuals incubated at constant low temperatures. Males and females responded similarly to the incubation treatment, but females developed a greater plasma bactericidal ability than males. We conclude that variation in innate immune function of adult birds is shaped by temperature fluctuations experienced during incubation.

Impact of temperature-humidity index on egg-laying characteristics and related stress and immunity parameters of Japanese quails

The aim of this study was to investigate the effect of temperature-humidity index (THI) level on productive parameters, welfare, and immunity in Japanese quails. One hundred and eighty (180) birds of Japanese quail, 14 weeks old, were used. Birds were divided randomly into three equal groups, control (at low THI, less than 70), H1 (at moderate THI, 70-75), and H2 (at high THI, 76-80). Birds in the control group had higher body weight (281.2 g, p = 0.001), egg mass (745 g, p = 0.001), fertility (85.4 %, p = 0.039), hatchability (80.4 %, p = 0.001), and immune response titer to Newcastle disease virus (p = 0.031), compared with H2 group. Furthermore, the thermoneutral group had higher internal egg quality score [albumen height (5.14 mm, p = 0.001), yolk height (10.88 mm, p = 0.015), yolk index (42.32 %, p = 0.039), and Haugh unit (92.67, p = 0.001)]. Nevertheless, there were no significant differences in fertility percentage, immune response, and corticosterone concentration between control and H1 group. Birds in the H2 group had the lowest total leucocytic count and lymphocyte percentage (p = 0.001 and 0.020, respectively) but the highest H/L ratio (0.83, p = 0.001). Corticosterone concentration was lower in control and H1 groups (5.49 and 6.41 ng/mL, respectively, p = 0.024) than that in H2 group. Japanese quail exposed to heat stress revealed drop in production and immunological parameters, as well as a detrimental effects on welfare. Thus, practical approaches might be used to reduce the detrimental effects of greater THI level.

Locally elevated cortisol in lymphoid organs of the developing zebra finch but not Japanese quail or chicken

Glucocorticoids are important for production of functional lymphocytes and immunity. In altricial neonates, adrenal glands are unresponsive and local glucocorticoid synthesis in lymphoid organs may be necessary to support lymphocyte development. Precocial neonates, in contrast, have fully responsive adrenal glucocorticoid production, and lymphoid glucocorticoid synthesis may not be necessary. Here, we found that in altricial zebra finch hatchlings, lymphoid organs had dramatically elevated endogenous glucocorticoid (and precursor) levels compared to levels in circulating blood. Furthermore, while avian adrenals produce corticosterone, finch lymphoid organs had much higher levels of cortisol, an unexpected glucocorticoid in birds. In contrast, precocial Japanese quail and chicken offspring did not have locally elevated lymphoid glucocorticoid levels, nor did their lymphoid organs contain high proportions of cortisol. These results show that lymphoid glucocorticoids differ in identity, concentration, and possibly source, in hatchlings of three different bird species. Locally-regulated glucocorticoids might have species-specific roles in immune development.

Immunomodulation and hormonal disruption without compromised disease resistance in perfluorooctanoic acid (PFOA) exposed Japanese quail

This study evaluated the impact of oral perfluorooctanoic acid (PFOA) on Japanese quail at concentrations found in American and Belgian workers at PFOA manufacturing facilities. Three arms of the immune system were tested; T cell, B cell, and innate immunity. After 6 weeks exposure, quail were challenged with E. coli infection to test the ultimate measure of immunotoxicity, disease resistance. The T cell response was lower in the high exposure groups. Antibody mediated, and innate immune responses were not different. Growth rate was higher, whereas thyroid hormone levels were lower in PFOA-exposed birds. Morbidity/mortality from disease challenge was not different among the control and PFOA-exposed groups, and no overt PFOA toxicity was observed pre-disease challenge. Although PFOA at 'worst case scenario' levels caused T cell immunosuppression, this did not translate into increased disease susceptibility, demonstrating that immunotoxicity testing must be interpreted with caution since disease resistance is the ultimate concern.

Towards the conservation of endangered avian species: a recombinant West Nile Virus vaccine results in increased humoral and cellular immune responses in Japanese Quail (Coturnix japonica)

West Nile Virus (WNV) arrived in North America in 1999 and is now endemic. Many families of birds, especially corvids, are highly susceptible to WNV and infection often results in fatality. Avian species susceptible to WNV infection also include endangered species, such as the Greater Sage-Grouse (Centrocercus uropbasianuts) and the Eastern Loggerhead Shrike (Lanius ludovicianus migrans). The virus has been shown to contribute towards the likelihood of their extinction. Although a clear and present threat, there exists no avian WNV vaccine available to combat this lethal menace. As a first step in establishing an avian model for testing candidate WNV vaccines, avian antibody based reagents were assessed for cross-reactivity with Japanese quail (Coturnix japonica) T cell markers CD4 and CD8; the most reactive were found to be the anti-duck CD8 antibody, clone Du-CD8-1, and the anti-chicken/turkey CD4 antibody, clone CT4. These reagents were then used to assess vaccine performance as well as to establish T cell populations in quail, with a novel population of CD4/CD8 double positive T cells being identified in Japanese quail. Concurrently, non-replicating recombinant adenoviruses, expressing either the WNV envelope or NS3 ‘genes’ were constructed and assessed for effectiveness as avian vaccines. Japanese Quail were selected for testing the vaccines, as they provide an avian model that parallels the population diversity of bird species in the wild. Both the level of WNV specific antibodies and the number of T cells in vaccinated birds were increased compared to unvaccinated controls. The results indicate the vaccines to be effective in increasing both humoral and cellular immune responses. These recombinant vaccines therefore may find utility as tools to protect and maintain domestic and wild avian populations. Their implementation may also arrest the progression towards extinction of endangered avian species and reduce the viral reservoir that potentiates infection in humans.

Avian IgY is selectively incorporated into the egg yolks of oocytes by discriminating Fc amino acid residues located on the Cυ3/Cυ4 interface

In avian species, maternal IgY is selectively incorporated into the egg yolks of maturing oocytes, but the relevance of receptor-mediated uptake is unclear. Here we investigated the critical amino acid residues of IgY required for egg yolk transport by conducting mutational analyses of selected residues located along the Cυ3 and Cυ4 domains of chicken IgY. Recombinant wild-type IgY-Fc (WT) and its mutants were synthesized, and their uptakes into the egg yolks of quail were determined. Among the 17 amino acid residues located on the Cυ3/Cυ4 interface, the substitution of Y363 at the Cυ3 domain to alanine abolished the IgY-Fc uptake into egg yolks. The comprehensive substitution of Y363 with other amino acids revealed that the residue at 363 needs to be allocated with aromatic amino acids to maintain the high transport ability. The deglycosylation of the N-linked carbohydrate chain by substituting N407 at the Cυ3 domain with alanine also caused a marked reduction of IgY-Fc uptake. The microscopic detection of the injected WT and Y363A mutant in ovarian follicles showed that the WT was concentrically accumulated in yolk granules, whereas the Y363A mutant was hardly accumulated in yolk granules, but it had infiltrated into the granulosa cell layer, suggesting that a major hurdle disturbing the infiltration of the Y363A mutant lies on the inside of the granulosa cell layer. The identification of important amino acid residues required for efficient IgY transport enhances our understanding of the molecular mechanisms underlying IgY transport through a specific IgY receptor in ovarian follicles.

Relative sensitivities of Japanese quail to foreign red blood cell challenges for immunotoxicity testing

Given evidence that the immune system is sensitive to environmental contaminants, evaluating immunocompetence in toxicology studies is increasingly important. By incorporating a test of humoral response into controlled reproductive and developmental studies, more comprehensive results can be gathered to assess the potential for disease. The foreign red blood cells (RBC) challenge is a minimally invasive method for evaluating humoral responses to a foreign antigen. Typically, antibody response is assessed following injections of sheep erythrocytes; however, Japanese quail (Coturnix japonica) are only minimally sensitive to sheep RBC. In the present study, adult Japanese quail were treated with 5% solutions of RBC from goose, goat, cow, donkey, or pig in primary and secondary challenges. After each treatment, plasma samples were taken and antibody responses were measured for total immunoglobulins (Ig), IgG, and IgM. Overall, goose RBC generated the poorest responses in both primary and secondary challenges, while the strongest antibody responses were to pig and donkey RBC. Therefore, pig RBC appear to be a superior antigen for testing humoral response in Japanese quail.

Validation of a disease model in Japanese quail (Coturnix coturnix japonica) with the use of Escherichia coli serogroup O2 isolated from a turkey

This study established a disease model and protocol for bacterial challenge with Escherichia coli serogroup O2 strain EC317 in Japanese quail. Five groups of 10 birds each were injected subcutaneously in the breast with 200 μL of a brain-heart infusion (BHI) culture containing 1 × 10(8), 1 × 10(7), 1 × 10(6), 1 × 10(5), or 1 × 10(4) colony-forming units/mL of the test organism, which had been isolated from a turkey with cellulitis and septicemia. Birds in a 6th group were controls that received sterile BHI alone. Localized lesions of cellulitis developed in all of the birds that received E. coli. The morbidity and mortality rates were highest (100%) in the birds receiving the highest dose of E. coli and decreased linearly with decreasing dose (P < 0.05). Severity of disease, including lesions of pericarditis and perihepatitis, was also directly proportional to the dose of E. coli. These findings indicate that this disease challenge protocol can be used to study disease resistance and immunologic consequences of contaminant exposure or other stressors in birds.

Immunotoxicity and disease resistance in Japanese quail (Corturnix coturnix japonica) exposed to malathion

The purpose of this study was to evaluate the impact of malathion on the immune system of wild birds, using Japanese quail (Coturnix coturnix japonica) as a model. Quail were exposed to malathion in drinking water at environmentally realistic concentrations (0 ppm, 1 ppm, and 10 ppm). In the fifth week, several arms of the immune response were tested using the T-cell based phytohemagglutinin (PHA) skin test, the B-cell mediated antibody response, and the chemiluminescence assay measuring innate immunity. After the sixth week of malathion exposure, quail were challenged with E. coli O2. The bursa of Fabricius and the spleen were assessed for histopathology. No clinical signs of malathion toxicity were observed. Morbidity or mortality subsequent to E. coli exposure tended (P = 0.08) to be higher in the high exposure group (50.0%) compared to the control (22.2%) group. There was no difference in the innate immune response in the malathion exposed birds, however, humoral immunity was suppressed (P = 0.03) with the higher malathion exposure. Histopathological evaluation revealed an immunosuppressive effect of malathion on the bursa of Fabricius; bursal atrophy, decreased B-cell density and increased apoptosis in the medulla, and increased connective tissue thickness of the follicular epithelium. Antibody suppression was correlated with bursal changes and peripheral blood lymphocyte count, the organ and cells involved in antibody production. Following the same pattern as other immunotoxicity tests, the PHA T-cell proliferative response also tended to be suppressed in the high exposure group. This study provides evidence that subchronic, moderate malathion exposure is immunotoxic to quail and that testing integrated, functional immunity using an infectious challenge is a better predictor of immunotoxicity than individual responses to immunotoxicity tests. The secondary antibody response, circulating lymphocyte populations, and bursal histopathology were the most sensitive indicators of immune status, as these predicted decreased disease resistance with malathion exposure.

Subchronic lead exposure, immunotoxicology and increased disease resistance in Japanese quail (Corturnix coturnix japonica)

The present study investigated the effects of lead (Pb) on immune responses in quail (Coturnix coturnix japonica) and the pathological impact of exposure to an infectious agent (E. coli O2). Fifty-four, 4-week-old quail were exposed to lead acetate in drinking water at 5 or 50 ppm. All birds were vaccinated with Newcastle Vaccine (NDV) during the third week of contaminant (Pb) exposure. In the fourth week, several arms of the immune response were tested using the T cell based phytohemagglutinin (PHA) skin test, the B cell mediated antibody response to NVD, and the chemiluminescence assay measuring innate immunity. Immunohistochemistry (IHC) was used to determine the expression of toll like receptor-3 (TLR-3) in the bursa of Fabricius. In the fifth week, quail were challenged with 200 μL of E. coli O2 (1×10(4) colony forming units (CFU)/mL). No clinical signs of Pb toxicity were observed. Morbidity/mortality subsequent to E. coli exposure was lowest in the high exposure group (27.8%) compared to low exposure (44.4%) and control (55.5%) groups. There was no difference in the T-cell-mediated PHA response, primary or secondary immune response or the innate response in Pb exposed groups; however, bursal TLR-3 increased (p<0.05) with higher Pb exposure. No evidence supported that subchronic Pb exposure was immunotoxic to quail at 5 or 50 ppm in drinking water. In contrast, our results provide evidence of a hormetic effect, with Pb exposed birds having lower morbidity and better survival than controls. Subchronic Pb exposure may be immunostimulatory rather than suppressive as predicted in earlier studies based on testing individual immune parameters.

Chronic stress and environmental enrichment as opposite factors affecting the immune response in Japanese quail (Coturnix coturnix japonica)

Procedures in the commercial production of animals involve stressful situations which lessen the animal's welfare. This study on Japanese quail evaluated whether an environmental enrichment manipulation can affect avian immune responses and if combined with a chronic stressor exposure can help to counteract the negative effects of stress on the immune system. Potential gender effects were also considered. After hatch, half of the birds were housed in non-enriched boxes and half were housed in environmentally enriched boxes. From day 33 to 42 of age, all birds within half of the non-enriched and enriched boxes remained undisturbed while the other half were daily exposed to a 15 min restraint stressor (chronic stressor). The inflammatory response (lymphoproliferation after phytohemagglutinin-p), percentage of lymphocytes, heterophil/lymphocyte (H/L) ratio and primary antibody response against sheep red blood cells were assessed. The chronic stressor application and the enrichment procedure, respectively, either increased or reduced the four immunological parameters evaluated and always in opposite directions. Males consistently showed lower antibody titres than females and presented the highest H/L ratio in response to the stressor when reared in the non-enriched environment. The findings indicate that submitting these animals to an enriched environment can be effectively used to improve their immune response and to reduce the detrimental effects of a stressor exposure.

Effect of dietary level of methionine on growth performance and immune response in Japanese quails (Coturnix coturnix japonica)

BACKGROUND

Methionine (Met) being the first limiting amino acid in maize/soybean-based quail diets, its supplementation provides scope for improvement of protein quality and reduction of dietary protein concentration. The question remains to what extent it can be incorporated in the diet of genetically improved quails. Therefore the effect of dietary Met level was assessed on growth performance and immune response in growing Japanese quails (n = 400) divided equally into 20 groups. Five dietary treatments (approximately 230 g kg(-1) crude protein and 12.14 MJ kg(-1) metabolisable energy) were formulated with 3.5, 4.5, 5.0, 5.5 and 6.0 g kg(-1) Met respectively, and each was offered to four groups of birds from 0 to 35 days of age.

RESULTS

Live weight at day 35 increased (P < 0.0001) up to 5.0 g kg(-1) dietary Met level but did not improve further at higher Met levels (5.5 and 6.0 g kg(-1)). Improved (P < 0.039) feed conversion ratio was achieved at 5.5 g kg(-1) Met level, which was statistically similar to that at 5.0 g kg(-1) Met level during 0-14 days of age. Cellular (phytohaemagglutinin from Phaseolus vulgaris) immune response increased (P < 0.0001) with increasing dietary Met concentration, whereas humoral (sheep red blood cells) immune response did not differ.

CONCLUSION

The optimal requirement of Met was 5.0 g kg(-1) for growth and 5.5 g kg(-1) for maximum cellular immune response.

Diurnal variation in the cellular and humoral immune responses of Japanese quail: role of melatonin

Experiments were conducted to determine if diurnal variations occur in the cellular and humoral immune responses of sexually mature, male Japanese quail and if this diurnal variation is mediated by the daily rhythm of melatonin. In Experiment 1, quail were exposed to LD 12:12 light-dark cycles and immune responses were measured in response to a single antigenic challenge given to different groups every 4h over a 24h period. Diurnal changes occurred in both the cellular and humoral immune responses. The cellular response was higher during the light phase than during the dark phase whereas the opposite was true for the humoral immune response. Experiment 2 was designed to determine if melatonin mediated these diurnal immune responses. Quail were maintained in continuous light (LL) to suppress endogenous melatonin production and half of them were given melatonin in the drinking water for 12h each day for 2 weeks. Contrary to control quail, significant daily variations occurred in both the humoral and cellular immune responses of birds given melatonin. As in Experiment 1, the cellular and humoral immune responses were out of phase with one another, with the humoral response being maximal when melatonin was present. We may conclude that there exists a melatonin dependent diurnal variation in both cellular and humoral immune responses of quail. The responses were inverse to one another during the daily light-dark cycle with the cellular response being maximal during the daily light period and the humoral response being maximal during the daily dark period.

Immunosenescence and age-related susceptibility to influenza virus in Japanese quail

We evaluated juvenile, pubescent, reproductive adult, and aged Japanese quail (Coturnix coturnix japonica) to determine if there were age-related differences in immune function with the hypothesis that aged birds would have weaker immune responses. Immune responses were measured using phytohemagglutinin (PHA) skin test, antibody response to foreign red blood cells and exposure to an H9N2 influenza virus. Adult birds consistently had stronger immune responses than young and aged birds. Aged quail had skin responses 38% lower than adults. Pubescent birds' mean anti-red blood cell response was four-fold lower than adult birds. Adults had greater increase in total anti-viral antibody between primary and secondary infections than all other groups. Our data demonstrate an age-related difference in immune function in Japanese quail that has similarities to age-related immunity in humans; younger and older animals had weaker immune responses compared to young adults.

Energetic trade-offs between immunity and reproduction in male japanese quail (Coturnix coturnix)

We investigated a postulated trade-off between reproduction and immune function by comparing the energetic costs of an immune response with phytohemagglutinin challenge (or injection) in castrated (low testosterone [T]) and intact (high T) Japanese Quail (Coturnix coturnix). Intact birds had higher resting metabolic rate (RMR) and significantly lower immune response than castrates. RMR of intact birds did not change in response to an immune challenge, suggesting that maintenance of reproductive tissues and associated high T is both immunosuppressive and energetically costly. Despite having a greater immune response than intact quail, castrates had a lower pre-challenge RMR than intact birds and paradoxically tended to decrease RMR during an immune challenge. This paradox may be because of pro-inflammatory cytokines that are released during immune responses. Cytokines promote energy conservation through malaise and soporific behaviors, possibly explaining the co-occurrence of a relatively strong immune response and a decrease in nocturnal RMR in castrates. The lower immune response in intact birds may not elicit as great a response of pro-inflammatory cytokines owing to an already elevated RMR from reproductive state, thus reducing any effect on RMR. The suppressed immune response and elevated RMR in intact birds may be because of T; however, we cannot separate the effects of T per se from the metabolic requirements of reproductive tissues.

Effect of higher levels of dietary selenium on production performance and immune responses in growing Japanese quail

1. The effect of increasing dietary selenium (Se) on production performance and immune responses in growing (0 to 6 weeks) Japanese quail was investigated. 2. One-day-old chicks (240) were randomly selected and divided into 12 groups with 20 chicks in each group (3 dietary treatments x 4 replicates). The basal diet contained 0.2 mg Se/kg and the two experimental diets were supplemented with 0.5 and 1.0 mg Se/kg. 3. Body weight gain, food intake and food conversion ratio and mortality were not affected by Se supplementation. 4. On d 28, antibody responses to inoculated sheep red blood cells were determined. Antibody titres were significantly higher after feeding the two Se-supplemented diets. 5. During week 4, the response to intradermally injected phytohaemagglutinin, an index of the in vivo cell-mediated immune response, was shown to be increased in the groups fed on the Se-supplemented diets. 6. After 6 weeks, the relative weights of the bursa of Fabricius and thymus were greater in the chicks given the Se-supplemented diets but there was no effect on the relative weight of spleen and liver. 7. It is concluded that supplementing the diet with Se has a beneficial effect on immune responses but does not affect production performance in growing Japanese quail.

Duck (Anas platyrhynchos), Japanese quail (Coturnix coturnix japonica) and other avian interleukin-2 reveals significant conservation of gene organization, promoter elements and functional residues

We compared the gene, promoter and cDNA sequences, and the predicted protein structure of duck and quail interleukin-2 (IL-2), a major immunomodulatory cytokine, with the known sequences of other avian and human IL-2. Analysis of the gene organization showed significant similarity with the overall organization of mammalian IL-2 genes, with four exons and three introns and a very short 5' untranslated regions. The second intron was the biggest in all the IL-2 sequences. The third intron was of similar size in chicken and quail, whereas in duck it was found to be slightly longer. Promoter sequence analysis of the IL-2 gene revealed remarkable conservation of the functionally important residues. The transcription factor binding sites such as those for AP-1, NF-AT, CD 28 RE and OCT, the TATA box and the predicted transcription start site with respect to chicken IL-2 sequence showed total conservation in duck, quail and turkey IL-2 promoters. Comparative analysis of the avian IL-2 cDNAs such as those of chicken, turkey, duck, quail, goose and Muscovy duck, revealed significant conservation of the nucleotide and predicted amino acid sequences. They showed nucleotide identity levels varying from 75% to 85%, amino acid level identity from 58% to 72% and amino acid similarity from 71% to 80% with each other. In the predicted protein secondary structure, the four essential alpha-helices and the hydrophobic amino acids in the heptad repeats forming the core structure of IL-2 molecules were conserved in all the avian and the human IL-2. The present study reveals high-level conservation of the gene; cDNA structure and regulatory elements of avian IL-2. This indicates highly conserved functions and probable functional cross-reactivity of this major immunomodulatory cytokine among birds.

Leptin increases T-cell immune response in birds

Leptin is a 16 kDa protein hormone that besides being a satiety factor also functions as a pleiotropic molecule regulating endocrine and immune functions. The aim of this study was to investigate the role of leptin on mitogen stimulated T-lymphocyte proliferation in birds. In the first experiment (in vitro), peripheral blood was collected from turkeys and lymphocytes were isolated from samples. Recombinant chicken leptin was added at concentrations of 0, 10(-9), 10(-8), 10(-7), and 10(-6) M prior to mitogen stimulation with Concavalin A. BrdU incorporation allowed us to detect T-cell proliferation using intracellular labeling of nucleic acids. Mitogen activation induced with Concavalin A caused a proliferation of T-cells that was positively correlated with the concentration of leptin. In the second experiment (in vivo), asian blue quail were fitted with osmotic pumps releasing leptin and injected with phytohemagglutinin (PHA) in their wing-webs before, during, and after leptin administration. The response to mitogen was greater in leptin treated birds during the leptin administration, but not before or after. These findings demonstrate that leptin enhances mitogen stimulated T-cell proliferation in birds. The results correspond with previous reports on mammals.

Effects of egg yolk testosterone on growth and immunity in a precocial bird

In oviparous vertebrates, maternal steroid allocation to eggs can have important fitness consequences for the offspring. However, elevated testosterone levels are not only associated with beneficial postnatal effects, such as enhanced growth and high social status, but may also entail costs by suppressing the immune system. In this study, testosterone levels in eggs of Chinese painted quail (Coturnix chinensis) were experimentally manipulated to evaluate its effects on growth and immunocompetence. Testosterone did not affect embryonic development, body size or growth during the first 20 days. However, elevated testosterone levels during embryonic development were immunosuppressive for chicks with inherently higher growth rate. Adaptive scenarios where only beneficial effects of increased testosterone levels are considered may therefore need to be re-evaluated.