Immunosuppression in chickens by aflatoxin

Evaluation of a Bacillus -Based Direct-Fed Microbial on Aflatoxin B1 Toxic Effects, Performance, Immunologic Status, and Serum Biochemical Parameters in Broiler Chickens

The aim of the present study was to evaluate the effect of a commercial Bacillus direct-fed microbial (DFM) on aflatoxin B1 toxic effects, performance, and biochemical and immunologic parameters in broiler chickens. Ninety 1-day-old Cobb 500 male broiler chicks were raised in floor pens for a period of 21 days. Chicks were neck-tagged, individually weighed, and randomly allocated to one of three groups: Negative control (basal feed), aflatoxin B1 (basal feed + 2 ppm AFB1), and DFM (basal feed + 2 ppm AFB1 + Bacillus direct-fed microbial). Each group had three replicates of 10 chickens (n = 30/group). Body weight and body weight gain were calculated weekly, while feed intake and feed conversion ratio were determined when broilers were 21 days old. On day 21, all chickens were bled, gastrointestinal samples were collected, and spleen and bursa of Fabricius were weighed. This study confirmed that 2 ppm of AFB1 causes severe detrimental effects on performance, biochemical parameters, and immunologic parameters, generating hepatic lesions in broiler chickens (P < 0.05). However, it was also observed that DFM supplementation provided beneficial effects that might help to improve gut barrier function, anti-inflammatory and antioxidant activities, as well as humoral and cellular immunomodulation. The results of the present study suggest that this Bacillus-DFM added at a concentration of 10⁶ spores/gram of feed can be used to counteract the negative effects that occur when birds consume diets contaminated with AFB1, showing beneficial effects on performance parameters, relative organ weights, hepatic lesions, immune response, and serum biochemical variables. The addition of this Bacillus-DFM might mitigate and decrease aflatoxicosis problems in the poultry industry, improving food security, alleviating public health problems, and providing economic benefits. Future studies are needed to fully elucidate the specific mechanisms by which this Bacillus-DFM counteracts the toxic effects of aflatoxin B1.

Assessment of Aflatoxin and Fumonisin Contamination and Associated Risk Factors in Feed and Feed Ingredients in Rwanda

Mycotoxins are fungal metabolites that contaminate crops, food, and animal feeds. Aflatoxins and fumonisins are among the mycotoxins that have been increasingly reported to affect health and productivity of livestock globally. Given that the health and productivity of livestock can directly influence human food safety and security, a study was conducted to assess the levels and factors for aflatoxin and fumonisin contamination in feed and feed ingredients in Rwanda. Aflatoxins and fumonisins were analyzed in 3328 feed and feed ingredient samples collected at six time points between March and October 2017 in all 30 districts of Rwanda. Of the 612 participants providing samples, there were 10 feed processors, 68 feed vendors, 225 dairy farmers, and 309 poultry farmers. Enzyme-Linked Immunosorbent Assay (ELISA) was used for aflatoxin and fumonisin analyses. Mean aflatoxin levels of 108.83 µg/kg (Median (MD): 43.65 µg/kg), 103.81µg/kg (MD: 48.4 µg/kg), 88.64 µg/kg (MD: 30.90 µg/kg), and 94.95 µg/kg (MD: 70.45 µg/kg) were determined for dairy farmers, poultry farmers, feed vendors, and feed processors, respectively. Mean fumonisin levels were 1.52 mg/kg (MD: 0.71 mg/kg), 1.21 mg/kg (MD: 0.56 mg/kg), 1.48 mg/kg (MD: 0.76 mg/kg), and 1.03 mg/kg (MD: 0.47 mg/kg) for dairy farmers, poultry farmers, feed vendors, and feed processors, respectively. Aflatoxin contamination was significantly affected by time of sampling and district from which feed samples originated (p < 0.05). Fumonisins did not show any correlation trends. Ninety-two percent of survey participants were unaware of aflatoxins and fumonisins and their adverse effects. This study has provided the basic understanding of the extent of feed contamination across the country and has established a baseline for future interventions in Rwanda. Further studies are needed to explore strategies for mitigating mycotoxins in the feed value chain in Rwanda.

Effect of dietary supplementation of mannanoligosaccharides on hepatic gene expressions and humoral and cellular immune responses in aflatoxin-contaminated broiler chicks

The present study was conducted to investigate the effects of dietary supplementation of mannanoligosaccharides (MOS) on expression of hepatic immunological genes and immune responses in aflatoxin-contaminated broiler chicks. A total of 336 seven-day-old Ross broiler chicks were randomly allotted to 7 experimental treatments with 4 replicates and 12 birds per replicate. Experimental treatments consisted of 2 aflatoxin levels (0.5 and 2 ppm) and 3 supplemental MOS levels (0, 1 and 2 g/kg) as a 2 × 3 factorial arrangement in comparison with a control group (unchallenged group). The chicks were challenged with a mix of aflatoxins during 7-28 d of age. Results showed that aflatoxin challenge resulted in the lower antibody titers against infectious bronchitis (IBV) and bursal (IBD) diseases viruses. In addition, aflatoxin-contaminated birds had a lower (P < 0.0001) lymphocyte percentage and a decline in (P < 0.01) interleukin-2 (IL-2) mRNA abundance. Likewise, heterophil proportion, heterophil to lymphocyte ratio and gene expressions of hepatic interleukin-6 (IL-6) and C reactive protein (CRP) were raised (P < 0.001) by increasing dietary aflatoxin level. Dietary inclusion of MOS increased (P < 0.05) antibody titers against IBV, IBD and Newcastle disease virus. Lymphocyte proportion and hepatic IL-2 gene expression were greater (P < 0.0001) in MOS-supplemented birds. Furthermore, supplemental MOS decreased hepatic IL-6 and CRP abundances. Additionally, inclusion of 2 g/kg MOS resulted in the upregulation (P < 0.01) of hepatic IL-2 gene expression in birds contaminated with 0.5 ppm aflatoxin. The present results indicate that supplemental MOS could improve cellular immunity via the upregulation of hepatic IL-2 gene expression in birds challenged with aflatoxins.

Evaluation of Cellulosic Polymers and Curcumin to Reduce Aflatoxin B1 Toxic Effects on Performance, Biochemical, and Immunological Parameters of Broiler Chickens

To evaluate the effect of cellulosic polymers (CEL) and curcumin (CUR) on aflatoxin B1 (AFB1) toxic effects on performance, and the biochemical and immunological parameters in broiler chickens, 150 one-day-old male broiler chicks were randomly allocated into five groups with three replicates of 10 chickens per pen: Negative Control (feed); AFB1 (feed + 2 ppm AFB1); CUR (feed + 2 ppm AFB1 + Curcumin 0.2%); CEL (feed + 2 ppm AFB1 + 0.3% Cellulosic polymers); and, CEL + CUR (feed + 2 ppm AFB1 + 0.3% Cellulose polymers + 0.2% Curcumin). Every week, body weight, body weight gain, feed intake, and feed conversion ratio were calculated. On day 21, liver, spleen, bursa of Fabricius, and intestine from five broilers per replicate per group were removed to obtain relative organ weight. Histopathological changes in liver, several biochemical biomarkers, antibody titers, and muscle and skin pigmentation were also recorded. Dietary addition of 0.3% CEL and 0.2% CUR separately significantly diminished some of the toxic effects resulting from AFB1 on performance parameters, relative organs weight, histopathology, immune response, and serum biochemical variables (P < 0.05); however, the combination of CUR and CEL showed a better-integrated approach for the management of poultry health problems that are related with the consumption of AFB1, since they have different mechanisms of action with different positive effects on the responses of broiler chickens.

Pathological effects of concurrent administration of aflatoxin B1 and fowl adenovirus-4 in broiler chicks

The current study was designed to investigate pathological effects of fowl adenovirus in broilers exposed to aflatoxin B₁. Fowl Adenovirus-4 (FAdV-4) infection is remerging in all types of poultry birds in Pakistan. Poultry feed contamination with mycotoxin (aflatoxin) is another important global issue. A total of 125-day old broiler birds were divided into six equal groups. Group A served as control. B and C groups were administered with aflatoxin B₁ (AFB₁) 100 and 200 μg/kg feed. Group D was infected with FAdV-4, while groups E and F administered with both AFB₁ (100 & 200 μg/kg) along with FAdV-4. These birds were monitored for clinical signs and mortality. Feed intake, body weight (BW), relative organ weights and gross & histopathological lesions were recorded. The highest mortality was observed in group F (FAdV-4 + AFB₁ 200 μg/kg feed) and the lowest mortality was observed in group B (AFB₁ 100 μg/kg feed). Body weights of all the groups were significantly (p < 0.05) lower as compared with control group. Relative weight of liver and kidneys in groups E and F were significantly higher as compared with control. Grossly, liver was swollen, anemic with round margins in groups D, E and F. Kidneys were also swollen with whitish areas indicating dead tissue. Microscopically intranuclear inclusion bodies were observed in group D-F. The hepatic parenchyma was also indicating necrotic changes along with vacuolar degeneration. In renal parenchyma, acute tubular necrosis was observed in groups C, E and F. It was concluded that AFB₁ intoxication lead to dose dependent changes in liver and kidneys. Severity of the changes was increased in interactive groups of AFB₁ with FAdV-4. Therefore, feed should be regularly monitored for AFB₁ levels and day old chicks for vertically transmitted FAdV-4 to prevent losses.

Immunotoxicology: A Brief History

Immunotoxicological research and testing have evolved from early studies of anaphylaxis to the robust and diverse field of immunotoxicology as we know it today. Early studies connecting immune dysfunction with exposure to exogenous agents focused on adverse reactions to immunogenic agents present in vaccines. Over time, work done by immunologists and pathologists leads to descriptions of characteristics of immunogenic agents as well as mechanisms by which anaphylaxis occurs and an understanding of the concept of immunosuppression. These myriad achievements greatly improved public health and led the field of immunotoxicology, which addresses all aspects of adverse immunological responses following exposure to exogenous agents as well as the development of testing paradigms to understand immunological responses of designed agents such as drugs and biologics.

Ameliorative Effects of Grape Seed Proanthocyanidin Extract on Growth Performance, Immune Function, Antioxidant Capacity, Biochemical Constituents, Liver Histopathology and Aflatoxin Residues in Broilers Exposed to Aflatoxin B₁

Aflatoxicosis is a grave threat to the poultry industry. Dietary supplementation with antioxidants showed a great potential in enhancing the immune system; hence, protecting animals against aflatoxin B₁-induced toxicity. Grape seed proanthocyanidin extract (GSPE) one of the most well-known and powerful antioxidants. Therefore, the purpose of this research was to investigate the effectiveness of GSPE in the detoxification of AFB₁ in broilers. A total of 300 one-day-old Cobb chicks were randomly allocated into five treatments of six replicates (10 birds per replicate), fed ad libitum for four weeks with the following dietary treatments: 1. Basal diet (control); 2. Basal diet + 1 mg/kg AFB₁ contaminated corn (AFB₁); 3. Basal diet + GSPE 250 mg/kg; (GSPE 250 mg/kg) 4. Basal diet + AFB₁ (1 mg/kg) + GSPE 250 mg/kg; (AFB₁ + GSPE 250 mg/kg) 5. Basal diet + AFB₁ (1mg/kg) + GSPE 500 mg/kg, (AFB₁ + GSPE 500 mg/kg). When compared with the control group, feeding broilers with AFB₁ alone significantly reduced growth performance, serum immunoglobulin contents, negatively altered serum biochemical contents, and enzyme activities, and induced histopathological lesion in the liver. In addition, AFB₁ significantly increased malondialdehyde content and decreased total superoxide dismutase, catalase, glutathione peroxide, glutathione-S transferase, glutathione reductase activities, and glutathione concentration within the liver and serum. The supplementation of GSPE (250 and 500 mg/kg) to AFB₁ contaminated diet reduced AFB₁ residue in the liver and significantly mitigated AFB₁ negative effects. From these results, it can be concluded that dietary supplementation of GSPE has protective effects against aflatoxicosis caused by AFB₁ in broiler chickens.

Aflatoxin B1 affects apoptosis and expression of death receptor and endoplasmic reticulum molecules in chicken spleen

Aflatoxin B₁ (AFB₁) is a natural product of the Aspergillus genus of molds, which grow on several foodstuffs stored in hot moist conditions, and is among the most potent hepatocarcinogens and immunosuppression presently known. The latter was related to the up-regulated apoptosis of immune organs. However, the effect of expression of death receptor and endoplasmic reticulum molecules in AFB₁-induced apoptosis of chicken splenocytes was largely unknown. The objective of this study was to investigate this unknown field. One hundred and forty four one-day-old chickens were randomly divided into control group (0 mg/kg AFB₁) and AFB₁ group (0.6 mg/kg AFB₁), respectively and fed with AFB₁ for 21 days. Histological observation demonstrated that AFB₁ caused slight congestion and lymphocytic depletion in the spleen. TUNEL and flow cytometry assays showed the excessive apoptosis of splenocytes provoked by AFB₁. Moreover, quantitative real-time PCR analysis revealed that AFB₁ induced the elevated mRNA expression of Fas, FasL, TNF-α, TNF-R₁, Caspase-3, Caspase-8, Caspase-10, Grp78 and Grp94 in the spleen. These findings suggested that AFB₁ could lead the excessive apoptosis and alter the expression of death receptor and endoplasmic reticulum molecules in chicken spleen.

Aflatoxin B1 Induced Systemic Toxicity in Poultry and Rescue Effects of Selenium and Zinc

Among many challenges, exposure to aflatoxins, particularly aflatoxin B₁ (AFB₁), is one of the major concerns in poultry industry. AFB₁ intoxication results in decreased meat/egg production, hepatotoxicity, nephrotoxicity, disturbance in gastrointestinal tract (GIT) and reproduction, immune suppression, and increased disease susceptibility. Selenium (Se) and zinc (Zn), in dietary supplementation, offer easy, cost-effective, and efficient ways to neutralize the toxic effect of AFB₁. In the current review, we discussed the impact of AFB₁ on poultry industry, its biotransformation, and organ-specific noxious effects, along with the action mechanism of AFB₁-induced toxicity. Moreover, we explained the biological and detoxifying roles of Se and Zn in avian species as well as the protection mechanism of these two trace elements. Ultimately, we discussed the use of Se and Zn supplementation against AFB₁-induced toxicity in poultry birds.

Aflatoxin contamination in corn sold for wildlife feed in texas

Supplemental feeding with corn to attract and manage deer is a common practice throughout Texas. Other species, including northern bobwhites (Colinus virginianus), are commonly seen feeding around supplemental deer feeders. In many cases, supplemental feeding continues year-round so feed supply stores always have supplemental corn in stock. Fluctuating weather and improper storage of corn can lead to and/or amplify aflatoxin contamination. Due to the recent decline of bobwhites throughout the Rolling Plains ecoregion of Texas, there has been interest in finding factors such as toxins that could be linked to their decline. In this study, we purchased and sampled supplemental corn from 19 locations throughout this ecoregion to determine if aflatoxin contamination was present in individual bags prior to being dispersed to wildlife. Of the 57 bags sampled, 33 bags (approximately 58%) contained aflatoxin with a bag range between 0.0-19.91 parts per billion (ppb). Additionally, three metal and three polypropylene supplemental feeders were each filled with 45.4 kg of triple cleaned corn and placed in an open field to study long-term aflatoxin buildup. Feeders were sampled every 3 months from November 2013-November 2014. Average concentration of aflatoxin over the year was 4.08 ± 2.53 ppb (±SE) in metal feeders, and 1.43 ± 0.89 ppb (±SE) in polypropylene feeders. The concentration of aflatoxins is not affected by the type of feeder (metal vs polypropylene), the season corn was sampled, and the location in the feeder (top, middle, bottom) where corn is sampled. It is unlikely that corn used in supplemental feeders is contributing to the bobwhite decline due to the low levels of aflatoxin found in purchased corn and long-term storage of corn used in supplemental feeders.

Aflatoxin B1 affects apoptosis and expression of Bax, Bcl-2, and Caspase-3 in thymus and bursa of fabricius in broiler chickens

Aflatoxin B1 is known as a mycotoxin that develops various health problems of animals, the effects of AFB1 on thymus and bursa of Fabricius in chickens are not clear. The objective of this study was to investigate the apoptosis of thymus and bursa of Fabricius in broilers fed with AFB1 . Two hundred Avian broilers were randomly divided into four groups of 50 each, namely control group and three AFB1 groups fed with 0.15 mg, 0.3 mg, and 0.6 mg AFB1 /kg diet, respectively. In this study, flow cytometer and immunohistochemical approaches were used to determine the percentage of apoptotic cells and the expression of Bax, Bcl-2, and Caspase-3. The results showed that consumption of AFB1 diets results in increased percentage of apoptotic cells and increased expression of Caspase-3 in both thymus and bursa of Fabricius. The expression of Bax was increased and the expression of Bcl-2 was decreased in the thymus, but no significant changes in Bax and Bcl-2 expression were observed in the bursa of Fabricius when broilers fed with AFB1 . These findings suggest that adverse effects of AFB1 on thymus and bursa of Fabricius in broilers were confirmed by increased apoptotic cells and abnormal expression of Caspase-3. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1113-1120, 2016.

Co-infection with Multiple Respiratory Pathogens Contributes to Increased Mortality Rates in Algerian Poultry Flocks

Respiratory infections are a common cause for increased mortality rates in poultry worldwide. To improve intervention strategies, circulating pathogens have to be identified and further characterized. Because of the lack of diagnostic tools, it was not known what pathogens contribute to the high mortality rates in association with respiratory disease in Algeria. Our objective was to determine if primary pathogens including Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), avian influenza virus (AIV), infectious bronchitis virus (IBV), and avian metapneumovirus (aMPV), known to be present in neighboring countries, can also be detected in Algerian chicken and turkey flocks. Results demonstrate the circulation of the investigated pathogens in Algerian poultry flocks as multi-infections. Phylogenetic characterization of the Algerian IBV strains confirmed the circulation of nephropathogenic viruses that are different from the strains isolated in neighboring countries. This could suggest the existence of a new IBV genotype in North Africa. Additionally, we detected for the first time an aMPV subtype B field strain and avian influenza virus. Interestingly, all viral pathogens were present in co-infections with MG, which could exacerbate clinical disease. Additional pathogens may be present and should be investigated in the future. Our results suggest that multiple respiratory infections may be responsible for high mortality in Algerian poultry flocks and very probably also in other regions of the world, which demonstrates the need for the establishment of more comprehensive control strategies.

Modulation of the spleen transcriptome in domestic turkey (Meleagris gallopavo) in response to aflatoxin B1 and probiotics

Poultry are highly susceptible to the immunotoxic effects of the food-borne mycotoxin aflatoxin B1 (AFB1). Exposure impairs cell-mediated and humoral immunity, limits vaccine efficacy, and increases the incidence of costly secondary infections. We investigated the molecular mechanisms of AFB1 immunotoxicity and the ability of a Lactobacillus-based probiotic to protect against aflatoxicosis in the domestic turkey (Meleagris gallopavo). The spleen transcriptome was examined by RNA sequencing (RNA-seq) of 12 individuals representing four treatment groups. Sequences (6.9 Gb) were de novo assembled to produce over 270,000 predicted transcripts and transcript fragments. Differential expression analysis identified 982 transcripts with statistical significance in at least one comparison between treatment groups. Transcripts with known immune functions comprised 27.6 % of significant expression changes in the AFB1-exposed group. Short exposure to AFB1 suppressed innate immune transcripts, especially from antimicrobial genes, but increased the expression of transcripts from E3 ubiquitin-protein ligase CBL-B and multiple interleukin-2 response genes. Up-regulation of transcripts from lymphotactin, granzyme A, and perforin 1 could indicate either increased cytotoxic potential or activation-induced cell death in the spleen during aflatoxicosis. Supplementation with probiotics was found to ameliorate AFB1-induced expression changes for multiple transcripts from antimicrobial and IL-2-response genes. However, probiotics had an overall suppressive effect on immune-related transcripts.

Effect of selenium supplementation on aflatoxin B₁-induced histopathological lesions and apoptosis in bursa of Fabricius in broilers

To investigate the effects of sodium selenite against aflatoxin B1 (AFB 1), 200 male Avian broilers, divided into five groups, were fed with basal diet (control group), 0.3 mg/kg AFB1 (AFB1 group), 0.3 mg/kg AFB1 + 0.2 mg/kg Se (+Se group I), 0.3 mg/kg AFB1 + 0.4 mg/kg Se (+Se group II) and 0.3 mg/kg AFB1 + 0.6 mg/kg Se (+Se group III), respectively. Compared with the control group, decreased relative weight of bursa of Fabricius and contents of serum immunoglobulin, more vacuoles and debris in the bursal lymphoid follicle, and increased percentage of apoptotic bursal cells were observed in the AFB1 group. Sodium selenite, however, could increase the relative weight of bursa of Fabricius and contents of serum immunoglobulin, and ameliorate histopathological lesions. The percentages of apoptotic bursal cells, through flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method, in the three +Se groups were lower than those in the AFB 1 group. Compared with the AFB 1 group, moreover, the mRNA expressions of Bax and Caspase-3 by qRT-PCR in the three +Se groups were decreased, while the expression of Bcl-2 was increased. The results indicate that sodium selenite in diet can protect chicken from AFB 1-induced impairment of humoral immune function by reducing bursal histopathological lesions and percentages of apoptotic bursal cells.

Toxicity of increasing aflatoxin B1 concentrations from contaminated corn with or without clay adsorbent supplementation in ducklings

A total of 1,280 1-d-old ducks were used in a study to investigate the effects of increasing aflatoxin B1 (AFB1) concentrations from naturally contaminated corn on young ducklings, and the effectiveness of a clay adsorbent (CA) to protect against those effects. Ducks were randomly allotted to 8 treatments (TRT) in a 4 × 2 factorial arrangement with 4 levels of AFB1 (0, 25, 50, and 100 μg/kg) and 2 levels of CA (0 and 0.1%) with 8 pens per TRT and 20 ducks per pen. All ducks were allowed ad libitum access to feed and water during the 21-d experiment. The ADG, ADFI, feed conversion rate, mortality, bill color, and CV of BW of each replicate were measured at the end of the study. Blood and tissue samples from 8 ducks per TRT were obtained on d 21 of the experiment to determine the serum immunoglobulin and protein concentrations, relative organ weights, and intestinal morphology. Average daily gain and relative weights of the liver, spleen, thymus, and bursa of Fabricius decreased linearly (P < 0.05) as dietary AFB1 increased. Serum proteins and intestinal villi heights and villus/crypt ratio followed the same pattern. Bill decolorization ratio, CV of BW, and mortality increased linearly (P < 0.05) as dietary AFB1 increased. Adding 0.1% CA to the diet improved (P < 0.05) the relative weights of the small intestine, spleen, and thymus, and the villus height and villus/crypt ratio of the duodenum and jejunum, as well as the serum IgG and IgM concentrations. Adding CA also reduced (P < 0.05) bill decolorization ratio, CV of BW, mortality, and serum IgA concentration. Therefore, duck performance was negatively affected by increasing AFB1 concentrations in diets. But the addition of 0.1% CA can protect against the detrimental effects caused by AFB1-contaminated corn in diets for ducks.

Aflatoxin B1 modulates the expression of phenotypic markers and cytokines by splenic lymphocytes of male F344 rats

Aflatoxin B1 (AFB1) is immunotoxic to animals and a suspected immunosuppressant in humans. In this study, we investigated the effects of AFB1 on splenic lymphocyte phenotypes and the inflammatory cytokine expression in male F344 rats. Exposure of animals to AFB1 [5-75 µg kg(-1) body weight (BW)] for 1 week showed dose-dependent decreases in the percentage of splenic CD8(+) T cells and CD3(-) CD8a(+) NK cells. A general inhibition of the expression of interleukin (IL)-4 and interferon (IFN)-γ by CD4(+) T cells, IL-4 and IFN-γ by CD8a(+) cells, and tumor necrosis factor (TNF)-α expression by natural killer (NK) cells was also found; however, no concurrent histological changes in spleen tissue were present, suggesting acute immunosuppression without overt toxicity. Five-week exposure with AFB1 significantly increased the percentages of CD3(+) and CD8(+) T cells, especially at low doses (≤ 25 µg kg(-1)). AFB1 treatment significantly decreased the anti-inflammatory cytokine IL-4 expression by CD4(+) T cells and significantly increased the pro-inflammatory cytokine IFN-γ expression by CD4(+) T cells and TNF-α expression by NK cells. These results indicated that repeated AFB1 exposure promotes inflammatory responses by regulating cytokine expression. Our data provides novel insights into the mechanisms by which AFB1 exposure differentially modulates the cell-mediated immune responses and suggests the involvement of an inflammatory response upon repeated exposure.

Effects of feeding corn naturally contaminated with aflatoxin B1 and B2 on hepatic functions of broilers

The purpose of this study was to evaluate the effects of feeding corn naturally contaminated with aflatoxin B(1) (AFB(1)) and aflatoxin B(2) (AFB(2)) on serum biochemical parameters, hepatic antioxidant enzyme activities, and pathological lesions of broilers. In total, 1,200 Cobb male broilers were randomly allocated into 5 treatments, with 8 replicates per treatment and 30 birds per replicate, in a 42-d experiment. The dietary treatments were as follows: control, 25, 50, 75, and 100% contaminated corn groups. Results showed that serum aspartate aminotransferase activity in the 75 and 100% contaminated groups were higher than that in the control group on d 21 (P < 0.05). Decreased content of hepatic total protein and increased activities of hepatic glutathione reductase and glutathione-S-transferase were observed as the percentage of contaminated corn increased (P < 0.05). The activity of superoxide dismutase and the content of hepatic malondialdehyde increased when the broilers were fed with more than 50% contaminated corn (P < 0.05). A reduction in glutathione peroxidase level was observed in the AFB(1)- and AFB(2)-contaminated groups on d 21 (P < 0.05). The average pathological lesion scores and apoptosis rate of liver cells increased as the concentration of dietary AFB(1) and AFB(2) increased. Ultrastructural changes were found in the livers of broilers fed 100% contaminated corn. In conclusion, diets containing AFB(1) and AFB(2) could induce pathological lesions in the livers, slightly change the serum biochemical parameters, and damage the hepatic antioxidant functions when the inclusion of AFB(1)- and AFB(2)-contaminated corn reached or exceeded 50%.

Evaluation of Acute Immunotoxicity of Aerosolized Aflatoxin B(1) in Female C57BL/6N Mice

There is evidence for immunotoxicity of aflatoxin B1 (AFB(1)) in chronic animal feeding studies; however, little information is available as to the effects of inhalation exposure. This study evaluated the acute affects of aerosolized AFB(1) on systemic immune function of female C57BL/6N mice following a single aerosol exposure. Mice were exposed in nose-only inhalation tubes to 0, 2.86, 6.59 and 10 mug AFB(1) aerosol/L air for 90 minutes. A negative control group of untreated mice and a positive control group of cyclophosphamide-treated mice were included to account for day to day variation. Three days following exposure, mice were sacrificed and body, liver, lung, thymus and spleen weights, and complete blood counts and white blood cell differentials were measured. Splenocytes were isolated for flow cytometric analysis of CD4(+) and CD8(+) lymphocytes, CD19(+) B-cells and natural killer cells (NK 1.1(+)). The effect of AFB(1) on humoral immunity was assessed by measuring serum anti-keyhole limpet hemocyanin (KLH) IgM levels. Of the tissues examined, only the thymus weight of AFB(1) exposed mice decreased significantly compared to naive mice; however, the decrease was not dose related and was also observed in the 0 AFB(1) aerosol control group. A decrease in the mean white blood cell count of treated vs. naive mice was observed at all dose levels but was clearly not dose related and was statistically significant only in the 0 and 2.86 mug/L groups. Red blood cell and platelet counts and white blood cell differentials were not significantly affected by AFB(1). The number of CD4(+) (helper T-cells), CD8(+) (cytotoxic T-cells) and CD19(+) (B-cells) decreased in spleens of AFB(1) aerosol exposed mice compared to naive mice; however, the decrease was not dose-related and was also observed in the 0 AFB(1) exposure group. Dose-related changes in the CD4(+)/CD8(+) T-lymphocyte ratios were not observed. The IgM response to KLH was not significantly different in AFB(1) compared to naive mice, suggesting that AFB(1) did not effect antigen-specific antibody production. Based on the results of this study, a single AFB(1) inhalation exposure up to 10 mug/L for 90 minutes (CxT = 900 mug .min/L) did not significantly alter the immune parameters measured in this study. The aerosol vehicle (ethanol) and/or stress could have masked subtle AFB(1)-dependent changes in thymus and spleen weights, and in splenic lymphocyte subpopulations. However, for other immunological parameters, such as the IgM response to KLH, there was clearly no significant effect of AFB(1) aerosol exposure.

Effect of graded levels of aflatoxin, ochratoxin and their combinations on the performance and immune response of broilers

1. The effects of dietary aflatoxin (AF, 0.5, 1.0 and 2.0 mg/kg), ochratoxin (OA, 1.0, 2.0 and 4.0 mg/kg) or combinations of these on body weight gain, feed efficiency, organ weights and immune response were studied in broilers. 2. Significant growth depression, reduced food consumption and poor food conversion efficiency were recorded in broilers fed a diet containing the greater concentrations of AF (1 and 2 mg/kg) and OA (2 and 4 mg/kg). 3. The combination of 2 mg/kg AF and 4 mg/kg OA exerted the maximum adverse effect on growth, feed intake and feed efficiency, indicating a synergistic effect on performance. 4. AF at 2 mg/kg in the diet caused a significant increase in the relative weight of liver, whereas the relative weight of kidney was significantly increased at 4 mg/kg of OA. A significant decrease in the relative weight of the bursa of Fabricius was noted at the highest concentration of AF (2 mg/kg) and combinations of 1 and 2 mg/kg AF and 2 and 4 mg/kg OA. 5. Cell mediated immunity (CMI), in terms of mean skin thickness (MST) sensitive to dinitrochlorobenzene (DNCB), was significantly reduced in chicks given the combination of 2 mg/kg AF and 4 mg/kg OA. Haemagglutination (HA) titre against sheep red blood cells (SRBCs) peaked at 42 d of age. At 42 and 47 d of age, a significant decrease in HA titres was recorded in chicks given 4 mg/kg OA or a combination of AF (1 or 2 mg/kg) and OA (2 or 4 mg/kg). 6. AF at a dietary concentration of 1 mg/kg or more and OA at 2 mg/kg or more, either alone or in combination, caused severe reductions in growth and immune response.

Understanding stress-induced immunosuppression: exploration of cytokine and chemokine gene profiles in chicken peripheral leukocytes

At present, the poultry meat and egg industry has gained a lot of ground, being viewed as a provider of a healthy alternative to red meat and other protein sources. If this trend is to be maintained, solutions must be found to improve resistance of chickens to disease, which often is weakened by stressful conditions. In poultry, stress-induced immunosuppression is manifested by failures in vaccination and increased morbidity and mortality of flocks. Currently, several modern cellular and molecular approaches are being used to explore the status of the immune system during stress and disease. It is likely that these new techniques will lead to the development of new strategies for preventing and controlling immunosuppression in poultry. Using quantitative reverse transcription-PCR assays, a broad spectrum of cytokine, chemokine, and their receptor genes can be quantified in birds and then be used as markers to assess the effects of stress on the immune system. Currently, we are investigating immune and endocrine interactions in the chicken, in particular the cells and molecules that are known to be involved in such interactions in mammals. We have evaluated the effects of corticosterone administration in drinking water on peripheral lymphocyte and heterophil cytokine and chemokine gene profiles. In particular, there seems to be effects on cytokine and chemokine mRNA expression levels in both lymphocytes and heterophils, especially expression of the proinflammatory cytokines interleukin (IL)-1beta, IL-6, and IL-18 and chemokines C-C motif, ligand 1 inflammatory (CCLi1); C-C motif, ligand 2 inflammatory (CCLi2); C-C motif, ligand 5 (CCL5); C-C motif, ligand 16 (CCL16); C-X-C motif ligand 1 inflammatory (CXCLi1); and C-X-C motif ligand 2 inflammatory (CXCLi2), which are initially upregulated and are potentially involved in modulating the adaptive immune response. A chronic treatment with corticosterone downregulates proinflammatory cytokines and chemokines, suggesting that the delayed effects of chronic stress can suppress the immune response. Messenger RNA expression levels of transforming growth factor-beta4 (TGF-beta4) are also upregulated in cortisosterone-treated birds. It appears that the balance between T-helper (Th) 1 and Th2/T regulatory cytokine production is altered in conditions associated with significant changes in plasma corticosterone concentration. Experiments are underway to decipher the cytokine and chemokine responses to vaccination and bacterial challenge on the background of stress-induced immunosuppression.

Aflatoxin B1 and its toxic effects on immune response of teleost fishes: a review

Aflatoxins represent, among all known mycotoxins, the best characterised and most investigated foodborne contaminants at present. This importance led to early research on acute and chronic toxicity. Further research showed that chronic toxicity due to aflatoxins could cause silent damages, causing the more evident carcinomas, being immunotoxicity one of the first toxicological effects studied on both mammals and aquatic farmed species, such as fishes. Although many of the aflatoxin immunotoxicity scientific information has been generated a quarter of century ago, the recent role of innate immune system on aquatic species still demands for up-to-date results, and expresses that the research on immunotoxicity caused by aflatoxins is yet to be completed. Based on these considerations, the aims of this review are to collect existing data on toxic effects on immune response of teleost fishes due to aflatoxins that could give us a perspective for the follow up research, and to gain new insights on the importance caused by the consumption of aflatoxin contaminated fish through the trophic chain.

Evaluation of antibody levels during simultaneous aflatoxicosis and vaccination against infectious laryngotracheitis in pullets

Chickens fed 200 ppb aflatoxin from 10 days of age were evaluated for their immune response to a modified live infectious laryngotracheitis vaccine. Vaccination was administered at age 4 and 12 weeks. Antibody titers to the vaccine were reduced in chickens given dietary aflatoxin. After 7 weeks, aflatoxin feeding was continued for one month in a treated group and was withdrawn in another. Serology indicated significant differences between the two treated groups relative to whether aflatoxin was fed or not. Significant reduction in body weights, antibody titers and elevated SGOT and SGPT levels were found in chickens treated with aflatoxin. The impact of aflatoxin on reduced body weight, decreased SGOT and SGPT levels and lower antibody titers was shown to be significant in the treated group fed on a ration of aflatoxin until throughout the experiment.

An evaluation of the metabolic basis of aflatoxin B1 toxicity by using buffalo granulocytes and agranulocytes in vitro

This study was aimed at monitoring cytotoxic changes in buffalo leukocyte subpopulations exposed to aflatoxin B1 (AFB1), since no such information is available for this species. The effects of AFB1 on glutathione (GSH) S-transferase, Ca2+Mg2+ATPase and protein synthesis in leukocyte subpopulations, namely, mononuclear (MN) cells and polymorphonuclear (PMN) cells isolated from the blood of the domestic buffalo (Bos bubalis), were studied. The cells were separated by using Ficoll-Paque and incubated in the presence of AFB1. GSH S-transferase activity was found to increase in cells exposed to AFB1, but there was no difference in activity between MN and PMN cells. PMN cell ATPase activity increased after AFB1 treatment, whereas no such effect was observed in the MN cells, which showed higher basal levels of ATPase activity. In the presence of AFB1, all the cells showed significant decreases in 14C-leucine incorporation, but the MN cells showed higher 14C-leucine incorporation than the PMN cells. Nevertheless, both cell types were affected by AFB1 and participated in its detoxification. There was also an appreciable decrease in the release of myeloperoxidase by activated PMN cells in the presence of AFB1.

Aflatoxicosis, infectious bursal disease and immune response to Newcastle disease vaccination in rural chickens

To investigate the immunosuppressive effects of infectious bursal disease virus (IBDV) and aflatoxin in indigenous chickens of Uganda, Newcastle disease (ND) seronegative chicks were randomly allocated to two treatment groups. Group A chicks were injected intramuscularly at the age of 3 weeks every 2 days up to four times with 0.250 mg aflatoxin B1 per bird, group B was infected occulo-nasally with IBDV 3 days prior to vaccination, while group C was left as a control group. All the chicks from the three groups were then vaccinated with Hitchner B1 vaccine at 21 days of age followed by a secondary vaccination with La Sota vaccine 3 weeks later. Humoral and cell-mediated immune responses were assessed by measuring antibody levels and delayed hypersensitivity reaction post vaccination. Growth performance in the three groups was assessed by weekly body weights while evidence of excretion of vaccinal ND virus was detected by reverse transcription-polymerase chain reaction.A significant (P < 0.05) reduction in the haemagglutination inhibition of ND antibody titre following initial priming with Hitchner B1 and subsequent booster with La Sota vaccines and a delayed hypersensitivity test following sensitization with dinitrochlorobenzene showed aflatoxin to be a more potent immunosuppressant than IBDV. Aflatoxin exerted its maximum effects during primary antibody response in the second and third weeks post vaccination. Aflatoxin and IBDV did not affect growth rates (P > 0.05) but prolonged La Sota vaccine virus excretion in faeces. Under our experimental conditions, aflatoxin and IBDV do not significantly affect the immune response of rural chickens to ND vaccination.

Efficacy of sodium bentonite as a detoxifier of broiler feed contaminated with aflatoxin and fumonisin

Sodium bentonite (SB) was evaluated for its ability to reduce the deleterious effects of fumonisin B1 (FB1) and aflatoxin B1 (AFB1) in broiler diets. It was incorporated into the diets (0.3%) containing 2.5 mg/kg AFB1, 200 mg/kg FB1, or a combination of 2.5 mg/kg AFB1 and 200 mg/kg FB1. Aflatoxin B1 significantly diminished body weight gain, whereas FB1 or the combination of FB1 and SB had no effect. Addition of SB in the diets significantly diminished the inhibitory effects of dietary AFB1. Feeding AFB1 alone caused significant increases in the relative weights of most observed organs. Feeding FB1 alone did not alter relative weights of any organs. In the combined diet (AFB1 plus FB1) relative weights of the liver, kidney, gizzard, and spleen were increased. Addition of SB to the diet containing AFB1 diminished the relative weights of liver, kidney, and spleen. Addition of SB to diets containing AFB1 and FB1 only decreased liver weights. In relation to the control, lower serum levels of total protein, albumin, and globulins were observed for all AFB, containing diets without SB addition, whereas all other treatments were not altered. Livers of birds fed diets containing AFB1 and a combination of AFB1 and FB1 were enlarged, yellowish, friable, and had rounded borders. The histopathology of them, stained with hematoxylin and eosin, showed multifocal and varied cytoplasmatic vacuolization with perilobular location. Incorporation of SB reduced the incidence and severity of the hepatic histopathology changes associated with aflatoxicosis.

Immune response to a mucosally administered aflatoxin B1 vaccine

In the present study, a mucosal vaccine was used in an effort to elicit serum IgG and intestinal secretory IgA against the mycotoxin aflatoxin B1 (AFB) in chickens. AFB was coupled to carrier proteins (BSA and porcine thyroglobulin) for use as a vaccine and ELISA coating antigen, respectively. Seven-day-old broiler chicks were divided into groups of 10 and immunized with one of four vaccine preparations: 1) AFB-BSA conjugate alone, 2) AFB-BSA linked to the B subunit of the recombinant heat-labile enterotoxin of Escherichia coli (rLT-B), 3) AFB-BSA admixed with rLT-B, or 4) AFB-BSA mixed with cholera toxin (CT). Each vaccine preparation was administered perorally, intrarectally, or intraperitoneally, with a booster immunization given 2 wk later. Sera and feces were collected weekly and assayed using isotype specific ELISA. All three routes of immunization elicited significant serum IgG responses; however, the intraperitoneal route was strongest for all vaccine preparations tested. The serum IgG immune response to the AFB-BSA conjugate was enhanced by co-administration of rLT-B but not by covalent coupling to rLT-B or coadministration with CT. Secretory IgA anti-CT and anti-rLT-B antibodies were detected in fecal supernatants, but no anti-AFB responses could be detected. As all 12 treatment groups produced significant levels of serum IgG anti-AFB, any of these approaches, including oral administration without adjuvant, may afford the chicken some level of protection through simple immuno-interception of free AFB.

Immunosuppression in broiler chicks fed aflatoxin and inoculated with fowl adenovirus serotype-4 (FAV-4) associated with hydropericardium syndrome

A total of 240 unvaccinated day-old broiler chicks, which had been found to be negative for antibodies against FAV-4, were divided into four groups of 60 chicks each. Group A was fed aflatoxin at 1 ppm from 7 days to 7 weeks of age. Group V was infected intra-abdominally at 14 days of age with 0.2 ml of FAV-4, having a titre of 10(5.5) TCID50 per 0.2 ml. The combined group AV was given the aflatoxin and infected with FAV-4. The fourth group C served as the control. More pronounced clinical signs, a higher mortality rate (56.7%), and reductions in body weight gain and in the organ to body weight ratios of the bursa and spleen were recorded in group AV. A significant (p < 0.01) reduction in the HI antibody titre following vaccination against Newcastle disease, and of skin thickness in the delayed hypersensitivity test following sensitization with DNCB, indicated an additive immunosuppressive effect from aflatoxin and FAV-4 on the humoral and cell-mediated immune responses in group AV compared to groups A and V. Microscopically, marked depletion and degeneration of lymphocytes in the thymus, bursa, spleen and caecal tonsils were observed in group AV up to 5 weeks PI.

Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective

Damp buildings often have a moldy smell or obvious mold growth; some molds are human pathogens. This has caused concern regarding health effects of moldy indoor environments and has resulted in many studies of moisture- and mold-damaged buildings. Recently, there have been reports of severe illness as a result of indoor mold exposure, particularly due to Stachybotrys chartarum. While many authors describe a direct relationship between fungal contamination and illness, close examination of the literature reveals a confusing picture. Here, we review the evidence regarding indoor mold exposure and mycotoxicosis, with an emphasis on S. chartarum. We also examine possible end-organ effects, including pulmonary, immunologic, neurologic, and oncologic disorders. We discuss the Cleveland infant idiopathic pulmonary hemorrhage reports in detail, since they provided important impetus for concerns about Stachybotrys. Some valid concerns exist regarding the relationship between indoor mold exposure and human disease. Review of the literature reveals certain fungus-disease associations in humans, including ergotism (Claviceps species), alimentary toxic aleukia (Fusarium), and liver disease (Aspergillys). While many papers suggest a similar relationship between Stachybotrys and human disease, the studies nearly uniformly suffer from significant methodological flaws, making their findings inconclusive. As a result, we have not found well-substantiated supportive evidence of serious illness due to Stachybotrys exposure in the contemporary environment. To address issues of indoor mold-related illness, there is an urgent need for studies using objective markers of illness, relevant animal models, proper epidemiologic techniques, and examination of confounding factors.

Effects of aflatoxin and carotenoids on growth performance and immune response in mule ducklings

The purpose of this study was to investigate if carotenoids could alleviate the adverse effects caused by aflatoxin with respect to growth performance and immune response. In two experiments, a total of 320 mule ducklings were assigned to 5 treatments, i.e. control, aflatoxin B(1) (AFB(1)) 200 ppb, AFB(1) +beta-carotene (BC) 200 ppm, AFB(1)+BC 400 ppm, and AFB(1)+astaxanthin (AS) 200 ppm. In experiment 1, the addition of beta-carotene or astaxanthin in the diet containing AFB(1) 200 ppb resulted in a significant decrease in average daily gain as compared with the control. AFB(1) 200 ppb alone and the addition of BC or AS on top of AFB(1) resulted in a significantly lower daily feed intake than for the control group. There were no significant differences in relative organ weights among treatment groups. Both treatments of BC 400 ppm and AS 200 ppm had significantly more macrophages harvested per duck than the control and AFB(1) 200 ppb treatments. However, there were no significant differences among treatments in percentages of phagocytotic macrophages and number of Candida albican phagocytized by phagocytotic macrophages. In experiment 2, blood biochemical parameters and antibody titers were evaluated. There were no significant differences among treatments in total bilirubin content and alkaline phosphatase activity in the serum or in antibody titers against fowl cholera. However, AFB(1) treatment had the highest activities of AST and ALT in the serum. The addition of BC 400 ppm on top of AFB(1) significantly reduced ALT activity as compared with the AFB(1) 200 ppb treatment. These results suggest that carotenoids could provide a slightly toxic alleviating effect on growth performance, enhance the chemotaxis ability of macrophages, and reduce ALT activity elevated by AFB(1).

Ameliorative effects of sodium bentonite on phagocytosis and Newcastle disease antibody formation in broiler chickens during aflatoxicosis

The ameliorative effect of graded levels of dietary sodium bentonite (0.2, 0.4 and 0.6 per cent wt/wt of feed) on in vitro-impaired phagocytosis and suppressed immune response to Newcastle disease vaccine during aflatoxicosis (AF) in broiler chicks was investigated. Both percentage and mean of phagocytic activities were decreased significantly (P < 0.05) in chicks fed 2.5 mg aflatoxin per kg feed. The addition of sodium bentonite was significantly effective in ameliorating the negative effect of AF on the percentage and mean of phagocytosis. The presence of AF alone in the diet depressed the immune response of chicks as measured by haemagglutination inhibition (HI) test. Sodium bentonite was also effective in ameliorating the suppressive effect of AF on the HI -titre in chicks vaccinated against Newcastle disease. The best results obtained when sodium bentonite was added at the rate of 0.4 per cent wt/wt of feed to the AF-containing diets.

Comparison of the effects of dietary selenium, zinc, and selenium and zinc supplementation on growth and immune response between chick groups that were inoculated with Salmonella and aflatoxin or Salmonella

The effects of four diets (basal diet, Se, Zn, and Se- and Zn-enriched diets) fed to chicks that were administered one of three treatments [Salmonella and aflatoxin inoculation (T1), Salmonella inoculation (T2), or uninoculated (T3)] were investigated for growth and immune responses. We found a significant improvement in growth performance represented by relative body gain (RBG) and feed efficiency (FE), for the Zn- and Se + Zn-enriched diets fed to the T1 and T2 groups. The antibody immune response was significantly improved for the Se enrichment diet in the T1 and T2 groups. The weight of the bursa and thymus, which relate to the level of the immune response, showed significant decreases, whereas the spleen had a significantly increased relative weight (RW) in the T1 group. The variable dietary trace elements supplement increased the thymic RW in the T2 group.

Model of physiological stress in chickens 2. Dosimetry of adrenocorticotropin

Continuous adrenocorticotropin (ACTH) delivery by mini-osmotic pumps is a reliable method to induce stress in broilers. The present study was conducted to determine the minimum effective dose of ACTH that will evoke physiological stress. Chicks, which had been reared under floor-pen conditions until 5 wk of age received mini-osmotic pumps by surgical implantation. The mini-osmotic pumps delivered 2, 4, 8, or 16 IU of porcine ACTH/kg BW/d for 7 consecutive d. Controls (CON) were untreated chicks. Continuous infusion of ACTH caused dose-related stress responses. Chicks that received 8 or 16 IU showed the greatest responses, whereas those that received 2 or 4 IU were intermediate to the birds dosed with high ACTH and the CON birds. Responses included decreased BW; decreased relative weights of the bursa of Fabricius, thymus, and spleen; and increased relative liver weight. Concomitantly, increased liver lipid and decreased liver moisture were recorded. Plasma concentrations of corticosterone (CS), glucose (GLU), total protein (TP), cholesterol (CHOL), and triglycerides (TRI) and the ratio of heterophils to lymphocytes were increased during ACTH infusion. ACTH infusion at 8 IU/kg BW/d for 7 d was determined to be the minimum effective dose that caused physiological stress in broilers.

Model of physiological stress in chickens 1. Response parameters

A model was developed to study stress in chickens. Continuous administration of adrenocorticotropic hormone was employed (ACTH) using physiological mini-osmotic pumps. A validation of controls for this procedure showed that nonhandled (NHCON), sham surgical procedure for pump implantation (SMCON) and surgical implantation of a pump delivering saline (SALCON) were all acceptable controls. Continuous delivery of ACTH at 8 IU/kg BW/d for 7 d caused increases in plasma corticosterone (CS), glucose (GLU), cholesterol (CHOL), triglycerides (TRI), high-density lipoprotein (HDL), total protein (TP), and the heterophil/lymphocyte (H/L) ratio. Body weight, as well as relative weights of the major immunobiological organs (i.e., spleen, thymus, and bursa of Fabricius) were decreased. Finally, liver was increased due to lipid and moisture accumulation. This model is the first to show in a single experiment all the major adaptive stress responses of chickens.

Effects of fumonisin B1 on selected immune responses in broiler chicks

Three experiments were conducted to evaluate immune responses in chicks fed fumonisin B1 (FB1). Day-old male chicks were randomly allotted to dietary treatments: 0, 50, 100, or 200 mg FB1/kg diet. In Experiment 1, chicks were fed diets for 3 wk and were injected intravenously with 4.6x10(6) Escherichia coli on Day 21. Blood samples were collected at 60, 120, and 180 min postinjection, and liver, spleen, and lung were collected after 180 min. Chicks fed 200 mg FB1/kg diet had significantly higher numbers of bacterial colonies in blood, spleen, and liver (P<0.05) than control chicks. In Experiment 2, chicks were placed on the diets for 4 wk and were injected with 0.5 mL inactivated Newcastle Disease virus vaccine on Weeks 2 and 3 of the experiment, and primary and secondary antibody titers were measured 7 d after each injection. The secondary antibody response in chicks fed 200 mg FB1/kg diet was significantly lower (P<0.05) than that of control chicks. In Experiment 3, lymphocyte proliferation in chicks exposed to FB1 in vivo or in vitro was determined. Results of the in vivo study showed that cell proliferation in response to mitogens was lower (P<0.05) in chicks fed 200 mg FB1/kg diet than in control chicks. For the in vitro study, cell proliferation was lower (P<0.05) when cells were exposed to > or = 2.5 microg FB1/mL. Data of the current study suggested that FB1 is immunosuppressive in chicks when present in the ration at 200 mg FB1/kg diet.

Humoral immunosuppressant activity of aflatoxin ingestion in rabbits measured by response to Mycobacterium bovis antigens using enzyme-linked immunosorbent assay and serum protein electrophoresis

A total of 30 New Zealand white rabbits were divided into five equal groups. Animals in groups 1 and 3 were sensitized with bacillus Calmette-Guerin (BCG), and those in groups 2 and 4 with inactivated cells of Mycobacterium bovis (Sensitinogen). Group 1 and 2 rabbits were fed 2 ppm day-1 aflatoxin for 3 months. Group 5 served as control. Serum samples from animals in all groups were subjected to enzyme-linked immunosorbent assays (ELISAs) to determine antibody titre and to protein electrophoresis to determine immunoglobulin levels. The antibody titres and the immunoglobulin levels were significantly decreased in the aflatoxin-treated groups.