A survey of T-2 toxin, ochratoxin, and aflatoxin for their effects on the coagulation of blood in young broiler chickens

The mediating role of coagulation function on the association of prenatal exposure to aflatoxin B1 and postpartum hemorrhage in Guangxi, China

Pregnant women are vulnerable to certain environmental agents, one of which is aflatoxin. As one of the most popular aflatoxins, Aflatoxin B1 (AFB1) has recently garnered increased attention concerning its potential association between exposure and adverse pregnancy outcomes. The aims of the study were to examine the associations between prenatal exposure to AFB1 and postpartum hemorrhage (PPH), and whether coagulation function has a mediating effect on their relationship. A total of 379 mother-infant pairs were included in the present study. Prenatal serum AFB1 albumin (AFB1-Alb) adduct levels in peripheral venous blood were detected by using an ELISA kit. Multiple linear and logistics regression models were applied to analyze the relationship between AFB1-Alb levels and PPH. We found mothers with high levels of AFB1-Alb adduct levels had significantly increased postpartum blood loss (partial regression coefficient (β) = 50.71, 95% confidence interval (CI) 3.48, 97.95). Mothers with high levels of AFB1-Alb adduct levels also had significantly increased risk of PPH (odds ratio (OR) = 4.81, 95% CI 1.01, 22.98). Moreover, concentrations of AFB1-Alb were positively associated with activated partial thromboplastin time (APTT) while negatively associated with fibrinogen (FIB). One-unit increase in APTT was correlated with a 6.62-ml (95% CI 3.04, 10.20) increase in postpartum blood loss. Mediation analysis suggested that the maternal blood APTT levels had a positive mediating effect in the association between AFB1-Alb adduct levels and postpartum blood loss (β = 0.32, 95% CI 0.04, 0.68). These results indicated that prenatal exposure to AFB1 was associated with increased postpartum blood loss, possibly by interfering with maternal APTT levels.

Ochratoxin A triggered intracerebral hemorrhage in embryonic zebrafish: Involvement of microRNA-731 and prolactin receptor

Ochratoxin A (OTA), a mycotoxin widely found in foodstuffs, reportedly damages multiple brain regions in developing rodents, but the corresponding mechanisms have not been elucidated. In this study, zebrafish embryos at 6 h post fertilization (hpf) were exposed to various concentrations of OTA and the phenomenon associated with intracerebral hemorrhage was observed at 72 hpf. Exposure of embryos to OTA significantly increased their hemorrhagic rate in a dose-dependent manner. Large numbers of extravagated erythrocytes were observed in the midbrain/hindbrain areas of Tg(fli-1a:EGFP; gata1:DsRed) embryos following exposure to OTA. OTA also disrupted the vascular patterning, especially the arch-shaped central arteries (CtAs), in treated embryos. Histological analysis revealed a cavity-like pattern in their hindbrain ventricles, implying the possibility of cerebral edema. OTA-induced intracerebral hemorrhage and CtA vessel defects were partially reversed by the presence of miR-731 antagomir or the overexpression of prolactin receptor a (prlra); prlra is a downstream target of miR-731. These results suggest that exposure to OTA has a negative effect on cerebral vasculature development by interfering with the miR-731/PRLR axis in zebrafish.

Human ochratoxin a biomarkers--from exposure to effect

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that has received particular attention because of the toxic effects, widespread occurrence in contaminated food and feed chain, suspected causal effect on nephropathies, and, more recently, possibility of exposure by inhalation in domicile and occupational settings. Biomarkers have been used not only to ascertain the role of OTA in inducing chronic renal failure diseases, but also as a means to portray general populations' risk to the mycotoxin. Biomonitoring can thus be used to assess internal OTA exposure, with no need to recognize the main source of exposure. And so it presents undeniable advantages over the monitoring of external dose. With a just right understanding of biomarkers, it is possible to follow the trail from exposure right to effect, and so contribute both to surveillance plans and etiological studies. In recognition of the long serum half-life and the renal elimination of OTA, most of the studies present serum/plasma and/or urine analyses as markers of exposure. In this review and for each of these main matrices, a comparison over the advantages and disadvantages is offered. Although currently limited, an overview of the current knowledge on OTA biomarkers and the influential role of the individual characteristics, namely gender and age, along with season and geographical location is given. Attention is also given to the ongoing debate over the existence of OTA-DNA adducts, a biomarker of effective dose regarded as an alternative to biomarkers of internal dose. Although unspecific, OTA effect biomarkers are also reviewed.

Fusarial toxins and their role in animal diseases

Fusarial toxins are toxic metabolites produced mostly by toxigenic micromycetes of genus Fusarium. Dominant mycotoxins of this group include trichothecenes, moniliformin, zearalenone, and fumonisins. Recently, special attention has been paid to these toxins because of their harmful effects on both animals and humans. On the basis of the available literature, we review here the characteristics of major fusarial mycotoxins with an emphasis on their toxic effects on animals. The most important fusarial mycotoxins, their sources, and their pathology including clinical signs, necropsy findings, as well as changes in haematological, biochemical, and immunological indices, are addressed.

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on production and metabolism in broilers

Three hundred sixty, 1-d-old male broiler chicks were fed diets containing grains naturally contaminated with Fusarium mycotoxins for 56 d. The four diets included control (0.14 mg/kg deoxynivalenol, 18 mg/ kg fusaric acid, < 0.1 mg/kg zearalenone), low level of contaminated grains (4.7 mg/kg deoxynivalenol, 20.6 mg/kg fusaric acid, 0.2 mg/kg zearalenone), and high level of contaminated grains without (8.2 mg/kg deoxynivalenol, 20.3 mg/kg fusaric acid, 0.56 mg/kg zearalenone) and with (9.7 mg/kg deoxynivalenol, 21.6 mg/kg fusaric acid, 0.8 mg/kg zearalenone) 0.2% esterified-glucomannan polymer derived from Saccharomyces cerevisiae1026 (E-GM). Body weight gain and feed consumption responded in a significant quadratic fashion to the inclusion of contaminated grains during the finisher period. Efficiency of feed utilization, however, was not affected by diets. The feeding of contaminated grains in the finisher period also caused significant linear increases in blood erythrocyte count and serum uric acid concentration and a significant linear decline in the serum lipase activity. Dietary inclusion of contaminated grains resulted in a significant quadratic effect on serum albumin and y-glutamyltransferase activity. Blood hemoglobin and biliary IgA concentrations, however, responded in significant linear and quadratic fashions. Supplementation of E-GM counteracted most of the blood parameter alterations caused by the Fusarium mycotoxin-contaminated grains and reduced breast muscle redness. It was concluded that broiler chickens may be susceptible to Fusarium mycotoxicoses when naturally contaminated grains are fed containing a combination of mycotoxins.

Assessment of factor V, VII and X activities, the key coagulant proteins of the tissue factor pathway in poultry plasma

1. Assay methods were developed for key components of the tissue factor pathway of blood coagulation, namely Factor V, Factor VII and Factor X. Using these assays, plasma from healthy laying hens, cockerels and broilers was shown to contain functional and equivalent amounts of each of these clotting factors. 2. The plasma activities for Factor V, Factor VII and Factor X can only be accurately determined when chicken tissue factor is used to initiate the coagulation mechanism in poultry plasma. Neither human tissue factor nor rabbit tissue factor forms a fully functional enzyme reactive complex with chicken Factor VII. 3. The overall tissue factor pathway coagulation mechanism was evaluated in plasma from laying hens, cockerels and broilers using the one-stage prothrombin time assay. As long as sufficient tissue factor was used, the overall clotting time results obtained with human recombinant tissue factor were not significantly different from those obtained with chicken tissue factor. 4. We conclude that poultry plasma does possess a fully functional tissue factor coagulation mechanism, but homologous chicken tissue factor must be used for in vitro assays of the components of this pathway.

Haematological and biochemical studies in broiler chicks fed ochratoxin and inoculated with inclusion body hepatitis virus, singly and in concurrence

Day-old broiler chicks, which had been shown to be negative for maternal antibodies against inclusion body hepatitis (IBH) virus and for viral antigen in cloacal swabs, were divided into four groups of 20 chicks each. One group was fed ochratoxin-A at 0.5 ppm from 3 to 38 days of age, another group was inoculated with 1 ml of IBH virus containing 10(6.5) EID50 per 0.2 ml. A third group was given both ochratoxin-A and infected with IBH virus. The fourth group served as the control. Anaemia was observed in all three treated groups but the changes were more pronounced in the combined group. The biochemical changes also suggested a cumulative damaging effect by ochratoxin-A and IBH virus.

Absorption and metabolism of nivalenol in pigs

The absorption and metabolism of nivalenol (NIV) were studied in pigs fed 0.05 mg NIV/kg BW, twice daily. Blood samples were taken during the first and third day, through catheters in the hepatic portal vein and peripheral mesenteric artery. Nivalenol was detected in most of the earliest blood samples, taken twenty minutes after the start of feeding. During 7.5 hrs after feeding, 11-43% of the NIV dose was absorbed. The systemic peak concentrations were 3-6 ng NIV/ml, mostly occurring 2.5-4.5 h after feeding. Sixteen hours after feeding, NIV was still being absorbed from the intestine, and the systemic concentrations were 1-3 ng NIV/ml. Nivalenol was mainly excreted in faeces, which contained concentrations up to 3.2 mg NIV/kg. No metabolites of NIV were found in plasma, urine, and faeces, either as glucuronic acid or sulphate conjugates, or as de-epoxy-NIV, indicating a lack of metabolism. The feeding of NIV did not cause feed refusal, and measured clinical plasma parameters were within the normal ranges.

Taxonomy, biology, and clinical aspects of Fusarium species

There are several taxonomic systems available for identifying Fusarium species. The philosophy used in each taxonomic system is discussed as well as problems encountered in working with Fusarium species in culture. Fusarium species are toxigenic, and the mycotoxins produced by these organisms are often associated with animal and human diseases. The implications for the association of the carcinogens, fumonisins, produced by Fusarium moniliforme and other Fusarium species with human diseases are discussed. Foreign-body-associated fusarial infection such as keratitis in contact lens wearers, onychomycosis, skin infections, and disseminated multiorgan infections are discussed. Disseminated fusarial hyalohyphomycosis has emerged as a significant, usually fatal infection in the immunocompromised host. Successful outcome is determined by the degree of immunosuppression, the extent of the infection, and the presence of a removable focus such as an indwelling central venous catheter. These infections may be clinically suspected on the basis of a constellation of clinical and laboratory findings, which should lead to prompt therapy, probably with one of the newer antifungal agents. Perhaps the use of such agents or the use of colony-stimulating factors may improve the outcome of this devastating infection. However, until new approaches for treatment develop, effective preventive measures are urgently needed.

Increased redness in turkey breast muscle induced by fusarial culture materials

Short-term feeding trials with experimentally moldy rice (10% of diet) or corn (12.5%) were carried out on turkey poults to screen for toxigenic Fusarium, Penicillium, and Aspergillus, which were recovered from corn or commercial turkey feed. A major finding was that culture materials of some fusaria increased the redness of turkey breast muscle without causing obvious hemorrhages either in the musculature or in the internal organs. Corn culture but not rice culture of Fusarium moniliforme (M-1325) depressed body weight gains, feed utilization, and heart weights (P = .01). The increased redness (reddish discoloration) could lead to the depreciation of fresh turkey muscle product.

Cytotoxicity and effects of T2-toxin on plasma proteins involved in coagulation, fibrinolysis and kallikrein-kinin system

The activity of both the coagulation and fibrinolytic systems was markedly depressed 24 h after a sublethal dose of T-2 toxin. T-2 toxin was active as an anticoagulant at low doses, which did not affect the basal state of the animals. The kallikrein-kinin system was also affected by depletion of the prekallikrein, which indicates increased bradykinin levels in plasma. At the same time there was an increased activity of some clinically relevant enzymes in serum, indicating tissue injuries caused by T-2 toxin. All effects observed in this study reached their maximum within 24 h after administration, which corresponds to the time animals usually die when receiving a lethal dose. T-2 toxin does not, however, seem to affect the protease enzymes by reduced protein synthesis, because of early onset of the effects, nor does it act as a trigger itself. The effect of T-2 toxin on plasma protease enzymes is probably secondary to cytotoxic effects in the vascular endothelium.

Effects of feeding deoxynivalenol (DON, vomitoxin)-contaminated wheat to female White Leghorn chickens from day old through egg production

White Leghorn chickens one day of age were fed starter and grower diets containing either a control (noncontaminated) wheat diet or a naturally contaminated deoxynivalenol (DON) wheat diet (18 mg DON/kg) from 1 day of age to the onset of egg production. The hens were then placed on their respective layer diets of control wheat or DON-contaminated wheat (18 mg DON/kg) for six 28-day egg production periods. Feeding the DON-contaminated diet did not significantly influence body weights during the growing or the laying phases. Overall, hen-day egg production and egg weights were significantly higher for hens receiving the DON diet. Feeding DON contaminated wheat caused no significant changes in percent shell, albumen height, percent fertility, percent hatch of fertile eggs, percent hatch of eggs set, or weight of chicks at hatch. There were slight, although significant, changes in shell weight and shell thickness and in some serum chemistry values. There were no significant differences in the hematology parameters measured or in prothrombin times. None of the eggs collected from hens fed the control and the DON-contaminated wheat diet contained detectable quantities of DON. Microscopic examination of sections of the liver, kidney, and proventriculus of control and treated hens revealed no unusual histopathology. The results indicate that feeding DON at relatively high levels beginning at 1 day of age and continuing through six egg production periods had only slight effects on the parameters measured.

Histopathologic and electron microscopic studies on the acute toxicity of ochratoxin A in rats

Ochratoxin A was given by gavage to male rats. Moribund and dead animals were necropsied, and the surviving rats, including the controls, were killed 48 hours after dosing. Many of the principal rats were moribund, or began dying, within 12 to 24 hours after dosing. Lesions suggestive of disseminated intravascular coagulation were seen by light microscopy as early as 12 hours after dosing; fibrin deposits were in the spleen, brain choroid plexus, glomerular capillaries, liver, and heart. Renal tubular nephrosis, hepatic and lymphoid necrosis, and necrotic enteritis with villous atrophy were also seen. Electron microscopy demonstrated fibrin strands mixed with degranulated platelets, necrotic leukocytes, and swollen endothelial cells in glomerular capillaries. Myocardial changes included focal supercontracted sarcomeres adjacent to intercalated disks. Swollen sarcolemma, lysed myofibrils and fragmented Z-bands with interstitial edema, vascular thrombosis, and endothelial damage were also seen. The acute pathologic changes induced by ochratoxin A in the intestine, liver, and lymphoid tissues were more obvious than the tubular nephrosis, and the development of a disseminated intravascular coagulation-like syndrome with myocardial changes was a complicating factor.

Induced aflatoxicosis in rabbits: blood coagulation defects

The effect of acute and subchronic experimental aflatoxicosis on blood clotting activity and platelets was evaluated. Male New Zealand White rabbits (weighing 2.4-3.2 kg each) were used. In Experiment 1, 19 rabbits were given orally 0.05 mg of aflatoxin B1 (AFB1)/kg of body weight daily from Day 0 through Day 23. Blood samples were collected before dosing and on Days 2, 5, 9, 12, 16, 19, and 23 of the experimental period. In Experiment 2, 40 rabbits were given a single dose of 0.4 mg of AFB1/kg of body weight. Blood samples were collected before dosing and at 12, 24, 36, and 48 hr after dosing. When compared to baseline and control animal values, one-stage prothrombin times and activated partial thromboplastin times of aflatoxin-dosed rabbits were lengthened, and there was a statistically significant decrease in fibrinogen, Factor IX, VIII, and V activities. Platelet counts were significantly increased in subacutely exposed rabbits, and platelet size was decreased in single high-dose treated groups. Factor deficiencies were attributed to a combination of decreased factor synthesis from hepatic insufficiency and consumptive coagulopathy or primary fibrinolysis.

Toxicity of Aspergillus ochraceus contaminated wheat and different chemical forms of ochratoxin A in broiler chicks

The toxicity of Aspergillus ochraceus contaminated wheat and various chemical forms of ochratoxin A (OA) were compared by feeding diets containing A. ochraceus contaminated wheat (3.0 micrograms OA/g diet) and 3.0 micrograms/g of purified OA in the K salt, Na salt, or organic acid form to broiler chicks from hatching to 4 weeks of age. All OA diets caused listlessness, emaciation, dehydration, and occasional diarrhea. Cumulative mortalities were 0, 13, 17, and 10% for the control, contaminated wheat, OA Na salt, OA K salt, and OA acid, respectively. Necropsies at the end of the experiment revealed pale friable livers, enlarged pale kidneys, and enlarged gall bladders in all OA treatments. Body weights and gain were significantly depressed throughout the experiment, and cumulative feed conversion ratios were significantly increased by all forms of OA. Relative kidney and liver weights were also significantly increased by all forms of OA. Serum analysis revealed significant decreases in total protein, albumin, globulin, cholesterol, and phosphorus concentrations and significant increases in uric acid concentrations in chicks fed all forms of OA. Determinations of median lethal dose (LD50) were conducted by dosing day-old chicks and recording mortality for 10 days. LD50 values were 4.41, 3.95, and 2.69 mg/kg for OA acid, Na salt, and K salt, respectively. These results indicated that the K salt of OA was more toxic than the Na salt in acute oral dosing. During the feeding study, results also suggested that chemical form of OA affected its toxicity, but after feeding 3.0 micrograms/g OA for 4 weeks, no significant differences in toxicity were caused by the various chemical forms of OA or the A. ochraceus contaminated diet.

Effects of acute ochratoxicosis on blood pressure and heart rate of broiler chickens

Male broiler chickens (Hubbard X Hubbard) were placed at hatching into electrically heated batteries with feed and water available ad libitum and maintained to 3 weeks of age under continuous lighting. In Trial 1, two replicate pens of 10 broilers per replicate were fed ochratoxin A from day-old to 3 weeks of age with treatments of 0, 2.0, and 4.0 micrograms/g ochratoxin A in feed (ppm). Trial 2 was identical to Trial 1 except that when the broilers reached 3 weeks of age they were administered an additional intravenous dose of either ochratoxin A, methoxamine, or isoproterenol. Trial 3 broiler chickens were maintained on control feed until they reached 3 weeks of age at which time they were taken off of feed for 2.5 hr and then placed on either control feed or feed containing 4.0 ppm ochratoxin A, and heart rate and blood pressure were measured every half hour through 7 hr. In Trial 1, no effect of ochratoxin A was seen in any treatment on heart rate or diastolic, systolic, or mean blood pressure. However, when an intravenous dose of ochratoxin A was administered to these broilers, a significant (P less than .05) decrease in heart rate and diastolic, systolic, and mean blood pressure occurred. The severity and duration of intravenous ochratoxin A administration were significantly (P less than .05) enhanced as the level of dietary ochratoxin A increased. The response of broilers to isoproterenol was significantly (P less than .05) altered by dietary ochratoxin A, whereas the broilers responded in a predictable manner to methoxamine without significant (P less than .05) ochratoxin A treatment effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Individual and combined effects of aflatoxin and ochratoxin A on bruising in broiler chickens

A 2 x 2 factorial design with treatments of 0 and 2.5 microgram/g aflatoxin and 0 and 2.0 microgram/g ochratoxin A was used to evaluate the individual and combined effects of these mycotoxins on bruising and blood thigh syndrome in broiler chickens. Trial 1 consisted of four replicate pens of 10 broilers per replicate, which were maintained on these dietary treatments from 0 to 3 weeks of age. At 3 weeks of age two replicate pens per treatment were randomly selected and placed on toxin-free feed with two replicate pens remaining on toxin feed until they were 6 weeks of age when the trial was concluded. In Trial 2 three replicate pens of 38 broilers per treatment were maintained on toxin feed from 0 to 3 weeks of age. At 3 weeks of age 13 broilers per replicate were placed on toxin-free feed with 25 broilers per replicate remaining on toxin until they reached 7 weeks of age when Trial 2 was concluded. These data indicate that a synergistic toxicity exists between aflatoxin and ochratoxin A to significantly (P less than .05) decrease body weight. Body weights of broilers on aflatoxin or ochratoxin A diets for only 3 weeks partially recovered by 6 or 7 weeks of age; however, the body weights of broilers on the interaction treatments for only 3 weeks remained significantly (P less than .05) depressed at 6 and 7 weeks of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Natural occurrences of ochratoxicosis in poultry

Five independent episodes of ochratoxicosis in about 970,000 turkeys, two episodes in about 70,000 laying hens, and two episodes in about 12,000,000 broiler chickens were investigated. Ochratoxin A concentrations in suspect feed and ingredients ranged from less than .2 to 16 ppm. Feed samples tested for T-2 toxin, F-2 toxin, heavy metals, and polychlorinated biphenyls were negative. Minor amounts of aflatoxin (less than 60 ppb) were found in suspect feed from two episodes. The main symptoms in turkeys were mortality (up to 59%), nephrotoxicity (pale, swollen kidneys that became tan colored in the sequel to acute toxicity), decreased feed consumption (as little as 20% of the normal feed intake) prior to death, and secondary air sacculitis. Histopathology revealed edema and necrosis of the proximal tubules of the kidneys and no changes in the liver or other organs. Suspect feed containing 2 ppm ochratoxin A increased uric acid levels in serum when fed to poults in the laboratory. The episodes in laying hens were characterized by reduced egg production, poor egg shell quality, and nephropathy. The episodes in broiler chickens were characterized by poor growth rate, poor feed conversion efficiency, poor pigmentation, nephropathy, and increased incidence of air sacculitis. Obtaining feed and ingredients free of ochratoxin, cleaning the feed and ingredient handling equipment, and adding antifungal agents to the feed proved beneficial. Eight of the 9 episodes were traced to the corn supply and the ninth episode was traced to corn gluten meal that became contaminated during storage after manufacture. Evidence was obtained that the ochratoxin was unstable and declined in concentration during storage. Aqueous acetone was a better solvent for extracting ochratoxin than was the recommended phosphoric acid: chloroform. The ochratoxin extracted from high potency samples consisted of ochratoxins A, B, and C in ratios of about 90:8:2.

Eimeria acervulina and Eimeria tenella infections in ochratoxin A-compromised broiler chickens

A 2 x 6 factorial experimental design was used to evaluate the effects of coccidial infections in ochratoxin A-compromised chicks. Ochratoxin A was incorporated into the feed at the dose levels of 0, .5, 1.0, 2.0, 4.0, and 8.0 micrograms/g toxin in feed (ppm), and fed to the birds from 1 day of age. Birds from each treatment were inoculated with either Eimeria acervulina or Eimeria tenella at 14 days of age. Ochratoxin A decreased the severity of lesions caused by both E. acervulina and E. tenella but did not prevent infection. Packed cell volume, hemoglobin concentration, relative weight of the kidney, and plasma protein levels were altered in a manner consistent with the independent effects of ochratoxicosis and coccidiosis. A combination of ochratoxin A and either species of coccidia produced a greater decrease in body weights, increase in feed conversions, and decrease in plasma carotenoid levels than either disease alone. The relative weight of the liver and level of plasma uric acid were altered in a manner that was dependent on the species of coccidia used. These data indicate that ochratoxin A and coccidial infections can interact to limit broiler performance and that some responses are directly related to the species of coccidia.

Avian gout caused by oosporein, a mycotoxin produced by Caetomium trilaterale

In a series of four experiments, diets containing oosporein at graded concentrations from 0 to 600 microgram/g were fed to male broiler chicks from hatching to 3 weeks of age. At dietary toxin levels of 100 microgram/g and below, no detrimental effects were observed. Dietary oosporein concentrations of 200 microgram/g and above elicited dose-related mortality resulting from severe visceral and articular gout. Three-week cumulative mortality percentages were 0, 13, 30, 57, and 95% for the 0, 200, 300, 400, and 600 microgram/g levels, respectively. Upon necropsy, the prominent lesions observed were massive urate deposits in various tissues, swollen and pale kidneys, dehydration, proventricular enlargement with mucosal necrosis, and a green discoloration of the gizzard lining. The effects on the proventriculus and gizzard occurred at doses as low as 200 microgram/g and were the most sensitive indicators of oosporein-toxicosis. In addition to the proventriculus, the relative weights of the kidney and liver were significantly increased in a dose-related fashion. A significant reduction in 3-week body weight at 400 microgram/g apparently resulted from the lower feed consumption concomitantly observed at this level of dietary toxin. Oosporein also caused an increase in water consumption at 400 and 600 microgram/g. Blood analyses indicated no toxin-related effect on plasma glucose, plasma protein, packed red blood cell volume, hemoglobin, and prothrombin times. The plasma concentration of uric acid was significantly elevated at 400 microgram/g. These data and mechanistic considerations suggest that oosporein should be classified as a nephrotoxin in the broiler chicken.

Aflatoxicosis and Intrinsic Coagulation function in broiler chickens

Aflatoxin was fed (0, .625, 1.25, 2.5, 5.0, and 10.0 microgram/g) to broiler chickens from day-old to 3 weeks of age when the birds were bled and intrinsic coagulation parameters measured. Clotting times of whole blood were increased by aflatoxin (2.5, 5.0, and 10.0 microgram/g) and decreased in blood samples activated by contact with the surface of crushed glass. There was no interaction of aflatoxin with the contact phenomenon. Partial thromboplastin times were significantly (p less than .05) prolonged by 5.0 and 10.0 microgram/g aflatoxin. Intrinsic activity as judged by whole blood thromboplastin generation was reduced nearly 40% by those two levels of aflatoxin. Activity analogous to human factor VIII was depressed by the two highest doses, but factor IX was significantly (P less than .05) reduced by only the highest dose fed, 10 microgram/g. These data suggest that chickens possess an intrinsic coagulation mechanism that is sensitive to aflatoxin but that the factor or factors responsible for the contact response are refractory to this important mycotoxin.

Effect of dietary aflatoxin on hemostasis of young turkey poults

Young turkey poults fed graded levels of aflatoxin (0, 125, 250, and 500 microgram/kg) from hatching for 3 weeks displayed altered hemostasis, manifested in prolonged prothrombin times at 2 and 3 weeks of age. Body weights were only affected in those groups receiving 500 microgram/kg. Total plasma protein, fibrinogen, and plasma calcium were reduced in response to dietary aflatoxin. In comparison with chickens, which exhibit similar hemostatic dysfunction concomitant with reduced body weight, turkeys receiving aflatoxin at lower levels exhibited an altered hemostatic response without exhibiting depressed body weights. Thus, the turkey hemostatic system is a better indicator of aflatoxicosis than is body weight gain.

Impaired vitamin E status of chicks fed T-2 toxin

Experiments were conducted to evaluate the toxicity of dietary T-2 toxin (4,15-diacetoxy-8-(3-methylbutyryloxy)-12,13-epoxy-delta 9-tricothecen-3-ol) in young pullets. Growth of day-old chicks fed a practical-type diet containing the toxin was described by the following function: Y = .152 + 58.497e(.305X1-.005X2(1.66); where Y = gain as percentage starting weight per week; X1 is time in weeks and O less than or equal to X2 is T-2 content of diet in ppm and O less than or equal to X2 less than or equal to 15. Chicks chronically exposed to the toxin showed compensatory growth upon its removal from the diet; however, latent effects on energy utilization were observed. Lesions of the oral mucosa produced by T-2 toxin showed spontaneous remission after about 14 days. T-2 toxin consistently produced depressed concentrations of vitamin E in plasma. Addition of micelle-promoting compounds (taurocholic, monoolein, and oleic acids) alleviated depressions in both plasma vitamin E and growth.

New evidence for intrinsic blood coagulation in chickens

Coagulation of blood in chickens is considered the result of an extrinsic clotting system initiated, as in mammals, by tissue thromboplastin released from injured tissues. Blood coagulation in mammals depends principally on an intrinsic mechanism in which thromboplastin is generated from blood itself. Only a negligible role, if any, has been ascribed to an intrinsic system in chickens. A reevaluation of intrinsic coagulation in chickens was undertaken in this study. Whole blood of chickens was found to clot over 30% faster when contacted by suitable surface activators such as kaolin or glass than when such contact was omitted. Plasma recalcification times were significantly (P less than .02) shortened by contact activators. Clotting functions were measurable both by partial thromboplastin time and activated partial thromboplastin time, tests that bypass extrinsic factors. Intrinsic thromboplastin could be generated from dilute whole chicken blood although at a slower rate than that reported for human blood. Modification of whole blood thromboplastin generation techniques permitted measurement of activities that seem analogous to human intrinsic factors VIII and IX but not XI or XII. These data provide evidence of a functioning intrinsic clotting mechanism in chickens. A complete description and role for this mechanism remains to be defined.

Glycogen storage disease type X caused by ochratoxin A in broiler chickens

Day-old broiler chickens fed graded concentrations of ochratoxin A (0, .5, 1.0, 2.0, 4.0, and 8.0 micrograms/g of diet) for 3 weeks were examined histopathologically for glycogen accumulation in muscle tissue using both formalin and ethanol fixatives with periodic acid-Schiff stain in a duplicate diastatic slide technique. However, glycogen could not be visualized in chicken muscle by these techniques which work with human muscle. Quantitative analysis for the glycogen itself permitted demonstration of a significant (P less than .05) fourfold increase in birds fed 8 micrograms/g. Using startled birds demonstrated that this accumulated glycogen was about 99% physiologically available. These findings coupled with prior reports permit the assignment on morphologic criteria of the hyperglycogenation of ochratoxicosis as a type X glycogen storage disease.

Experimental ochratoxicosis in turkey poults

Graded concentrations of ochratoxin A (0, 1, 2, 4, and 8 micrograms/g of feed) incorporated into the diet of turkey poults from hatching until 3 weeks of age resulted in a decreased growth rate, enlarged proventriculus and gizzard, and a regressed thymus (all at 4 and 8 micrograms/g) and the sizes of liver, spleen, pancreas, kidneys, bursa of Fabricius were unaffected. Feed conversion ratio increased from 1.63 (control value) to 2.07 (8 micrograms/g). Mortality was increased significantly (P less than .05) at 8 micrograms/g. Water consumption and plasma uric acid were increased at 4 and 8 micrograms/g. Plasma glucose and the dry weight of the kidneys decreased significantly at 8 micrograms/g while total plasma proteins, prothrombin time, plasma carotenoids, and phenol red clearance rate were unaltered. A leucocytopenia, which was primarily a lymphocytopenia, was observed at 4 and 8 micrograms/g. Heterophils decreased while basophils increased at 8 micrograms/g. The oral LD50 for day-old and 3-week-old poults was 4.63 +/- .31 and 7.84 +/- .94 mg/kg, respectively. Intraperitoneally, the value for day-old birds was .16 +/- .03 +/- mg/kg and for 3-week-old birds was .34 +/- .09 mg/kg. These data suggest that ochratoxin is a potent nephrotoxin in turkeys, but that ochratoxicosis in turkeys differs markedly from the disease in other species.

Intestinl fragility during ochratoxicosis and aflatoxicosis in broiler chickens

Graded concentrations of dietary ochratoxin (0, 0.5, 1.0, 2.0, 4.0, and 8.0 microgram/g) and aflatoxin (0, 0.625, 1.25, 2.5, 5.0, and 10.0 microgram/g) were fed to broiler chicks from hatching to 3 weeks of age. The breaking strength of the large intestines was decreased significantly (P < 0.05) by ochratoxin (2, 4, and 8 microgram/g), but not by aflatoxin. This fragility was accompanied by an increase in the weight of the large intestine relative to body weight of birds fed ochratoxin (4.0 and 8.0 microgram/g), whereas aflatoxin had no significant (P < 0.05) effect on this parameter. Lipid content of the large intestine was decreased significantly (P < 0.05) by aflatoxin (10.0 microgram/g) and increased by ochratoxin (8.0 microgram/g). Microscopic examination of cross sections of large intestines stained for collagen gave the impression of a great decrease in collagen content of birds fed ochratoxin, but not aflatoxin. The radial length of the collagenous longitudinal folds of the large intestine was decreased significantly (P < 0.05) by ochratoxin (2.0, 4.0, and 8.0 microgram/g). These observations, plus a field case characterized by intestinal ruptures causing carcass condemnations on the processing line and by the occurrence of aflatoxin and ochratoxin in the chicken feed, suggest a novel way in which mycotoxins cause economic loss to agriculture.

Evaluation of bone strength during aflatoxicosis and ochratoxicosis

Young chickens were fed graded levels of aflatoxin (0, 0.625, 1.25, 2.5, 5.0, and 10.0 mug/g of diet) or ochratoxin (0, 0.5, 1.0, 2.0, 4.0, and 8.0 mug/g of diet), and the breaking strength, displacement before failure, and diameter of their tibias were determined. Breaking strength was decreased at growth inhibitory levels of aflatoxin (2.5 mug/g) and ochratoxin (2 mug/g), whereas a reduction in diameter required higher levels (5.0 and 4.0 mug/g, respectively). Bones from birds with ochratoxicosis selected to have diameters equal to control bones had lower breaking strength. In an attempt to negate mathematically the effect of decreased diameter and bias in any selection process, stress at time of failure of the bones was calculated and found to be decreased by feeding aflatoxin but not ochratoxin. Total displacement of bones before breaking was increased significantly (P < 0.05) by both toxins at the highest levels administered, but this increase was primarily the result of an increase in displacement from the start of failure to complete failure. Increased displacement associated with both toxicoses was equal in bones selected to be of equal diameter or in bones from the same treatment but of different diameters. However, calculation of modulus of elasticity which is corrected for diameter revealed aflatoxin had no effect whereas ochratoxin tripled the effect. These data indicate that the material properties of bones can be altered during mycotoxicoses and suggest yet another way in which mycotoxins are detrimental to animal health.

The effect of dietary fat on the anticoagulant activity of aflatoxin B

A single i.p. dose of aflatoxin B1 had no significant effect on the thrombotest clotting times of monkeys subsisting on low-fat and high-fat dietary regimens, respectively. There was a significant interaction between aflatoxin and dietary fat level.

Decreased glycogen mobilization during ochratoxicosis in broiler chickens

Graded doses of pure ochratoxin A (0, 0.5, 1.0, 2.0, 4.0, and 8.0 microgram of toxin per g of feed) were incorporated into a commercial diet which was fed to chickens from hatching to 3 weeks of age, at which time the experiments were terminated. Liver glycogen levels were elevated significantly (P less than 0.05) by 4.0 and 8.0 microgram/g but not lower doses. Glucagon stimulation of glycogen mobilization was inhibited at the same concentrations. Histopathological examination revealed cytoplasmic but not nuclear deposits of glycogen in cells at the periphery of liver lobes. These data demonstrated that ochratoxin inhibited glycogenolysis. Impaired ability to generate glucose from glycogen could account for the increased susceptibility to cold stress previously reported to occur in ochratoxicosis. Based on present and prior observations, it seems possible that ochratoxin induces a syndrome which mimics the glycogen storage disease of type X which is caused by a deficiency in the cyclic AMP-dependent enzyme of the glycogenolytic enzymatic cascade.

Bioproduction of [14C]ochratoxin A in submerged culture

A number of Aspergillus and Penicillium species were tested for production of ochratoxin A (OA) in several media. After 8 days of static incubations of submerged cultures at 28 degrees C, toxin yields of 25 and 30 micrograms/ml were obtained with Aspergillus alliaceus NRRL 4181 in Ferreirás and 2% yeast extract-4% sucrose media, respectively. However, the largest production observed in the preliminary screening was 54 micrograms/ml; this highest level was produced by A. sulphureus NRRL 4077 in a modified Czapek solution. The medium contained the basal salts and sucrose of Czapek plus urea (3%) and corn steep liquor (0.5% solids). A time study of toxin production demonstrated maximum yield of 350 micrograms/ml by the A. sulphureus isolate in the modified Czapek medium after 11 days of static incubation at 28 degrees C. The optimal production conditions were employed in additional tests designed to measure the efficiency of 14C incorporation from sodium [1-14C]-acetate into OA. Samples (20 microCi) of sodium acetate were added to separate culture flasks at 24-h intervals during the initial 9 days of the fermentation. Addition of [14C]acetate on day 4 of incubation provided the maximum yield of labeled OA. The highest specific activity of labeled toxin obtained was 0.07 microCi/mg of OA and the maximum incorporation rate of labeled acetate was 5.3%.

Ochratoxicosis in White Leghorn hens

As ochratoxin-producing fungi are often isolated from poultry feeds and from cereals used in compounding these feeds, a study has been made of the effects of feeding ochratoxin A (OA) to laying birds. Four groups of White Leghorn hens were fed 0, .5, 1, and 4 ppm in the feed respectively. Egg production and feed consumption declined in the three groups given OA, while egg and body weight were depressed only by feeding higher levels of OA. Fertility and hatchability were unaffected by feeding OA. Prothrombin times were increased and total serum proteins were decreased after feeding 1 or 4 ppm for six weeks. After the withdrawal of the mycotoxin-contaminated feed, OA disappeared from the muscle after 24 hr but persisted in liver and kidney for more than 48 hr. No residues were found in fat or skin.