Experimental combined aflatoxin B1 and ochratoxin A intoxication in pigs

Twenty-one pigs weighing approximately 18 kg were placed in 7 groups of 3 and given diets containing respectively aflatoxin B1 alone at 0.375 and 0.0750 mg/kg, ochratoxin A alone at 1 and 2 mg/kg, 0.375 mg/kg of aflatoxin B1 plus 1 mg/kg of ochratoxin A and 0.750 mg/kg aflatoxin B1 and 2 mg/kg of ochratoxin A. The remaining group served as untreated control. At the respective dose levels, pigs receiving similar doses of ochratoxin A alone or in combination with aflatoxin B1, were similarly affected, the clinical effects of aflatoxin having been mostly obscured by those due to ochratoxin A. Mild degenerative hepatic changes typical of aflatoxicosis were observed in pigs fed this toxin alone or in combination with ochratoxin A. In kidneys of pigs fed diet containing 1 and 2 mg of ochratoxin A alone changes included interstitial fibrosis of the vortex and dystrophy and degeneration of the tubular epithelium. Similar lesions but less pronounced fibrosis were found in kidneys of pigs receiving both toxins. The respective lower dose levels of mycotoxins selected were judged to be about the no-effect levels for each dosed separately under the conditions of the trial. Such levels have been found not infrequently on mould affected grain and stock foods. The result highlights the difficulties that may be experienced in the recognition of such multimycotoxicoses as they are likely to occur in the field and indicate the need for toxicological analysis as well as pathological investigation in establishing a diagnosis.     

Ochratoxin A and citrinin induced nephrosis in Beagle dogs. III. Terminal renal ultrastructural alterations

The extent and type of renal ultrastructural changes in Beagle dogs varied with the administration of ochratoxin A and citrinin alone and in the two dosage combinations. The three predominant changes were cytoplasmic vacuolation, myelin figure formation and lesions designated as cytoplasmic disarray. These changes were mainly of the endomembane system of the tubular epithelial cells. Cytoplasmic vacuoles were within proximal and distal tubules and collecting ducts and were most numerous in dogs given 10 mg/kg critrinin. Vacuolation of similar distribution, but less severe, was seen in renal tubular cells of dogs given the higher dose of the combined mycotoxins (0.2 mg/kg ochratoxin A + 10 mg/kg citrinin). This damage was limited to the proximal tubular cells in dogs given only ochratoxin A (0.1 or 0.2 mg/kg). Myelin figures were in proximal epithelial cells of dogs given ochratoxin A alone or combined with citrinin. There was cytoplasmic disarray in dogs of all groups except for dogs given 5 mg/kg citrinin. This lesions was usually limited to the proximal tubules. The lesions, however, was found in cells of the distal tubules of dogs given 10 mg/kg citrinin alone.     

Mycotoxins in fungal contaminated samples of animal feed from western Canada, 1982-1994.

Feed samples from 94 cases involving fungal contamination and suspected mycotoxicosis of farm animals in western Canada were examined during 1982-1994 to assess the incidence of mycotoxins. Samples were analyzed for aflatoxins, ochratoxin A, citrinin, sterigmatocystin, and the fungal estrogen zearalenone. Samples infected with Fusarium fungi were additionally assayed for nivalenol, deoxynivalenol, fusarenone-x, 15-acetyl-deoxynivalenol, diacetoxyscirpenol, HT-2 toxin, and T-2 toxin. Mycotoxins were found in 21 feed samples from 17 cases (18% of the reported cases), generally at levels far below those needed to induce symptoms under laboratory conditions. HT-2 toxin and other type-A trichothecenes were detected in 5 samples, deoxynivalenol and other type-B trichothecenes in 13, ochratoxin A in 5, and citrinin in 2. In 9 cases, symptoms observed in the animals were consistent with the known effects of the mycotoxin(s) found in the particular feed samples.     

Experimental ochratoxicosis A in pigs

SUMMARY Ochratoxin A was isolated from a culture of Aspergillus ochraceus grown on a cornmeal substrate. The mycotoxin was added to a grower ration for 14 kg young pigs at 2, 4, 8 and 16 mg/kg and fed to groups of 3 for periods ranging from 6 to 20 days. The highest dose rate group only became sick, with loss of appetite, weight loss, polydipsia, polyuria, proteinuria, glucosuria, elevation of serum creatinine, pale swollen kidneys, renal tubular degeneration and cortical fibrosis. The pigs on the 2 mg toxin/kg of diet appeared unaffected with only slight renal tubular degeneration present in one animal. Feeding diet contaminated with the intermediate doses of 4 and 8 mg toxin/kg diet lead to reduction of weight gain and/or reduced feed intake and feed conversion efficiency as well as mild renal lesions. Ochratoxin A has recently been reported on mould-affected grain in Queensland and some local strains of A. ochraceus in culture have been shown to be able to produce levels of ochratoxin A of up to 4000 mg/kg of substrate. Rare episodes of nephrotoxicity in pigs seen at slaughter in Queensland may thus be due to prior contamination of the diet with ochratoxin A.     

Cold storage of wheat. 1. Ergosterol, ochratoxin A and citrinin after inoculation with Penicillium verrucosum]

Seed wheat was inoculated without having been sterilized with an ochratoxin A and citrinin forming strain of Penicillium verrucosum and stored at moisture contents of 18, 20, 22, 24, and 26% at 10 and 4 degrees C. The production of ergosterol, a chemical indicator of fungal biomass, started within the storage time investigated (240 days). Only at 18% H2O/4 degrees C an increase of the ergosterol content was not observed. Ochratoxin A and Citrinin were not detected at 18% H2O/4 degrees C and 20% H2O/4 degrees C within 240 days (detection limit: 10 and 25 micrograms/kg, respectively). At the other combinations of moisture content and temperature the first detection of the two toxins approximately coincided with the onset of ergosterol production. With increasing moisture content and temperature the time up to the start of ergosterol production decreased, whereas the production rates of ergosterol, ochratoxin A and citrinin increased. Both toxins were produced with about the same rate during a first phase of accumulation. At 20-26% H2O there was no influence of moisture content and temperature on the relation between toxin content and the simultaneously reached ergosterol content. It is recommended that wheat highly contaminated with Penicillium verrucosum should not be stored beyond the start of ergosterol production.     

Mechanisms of Mycotoxin-induced Dermal Toxicity and Tumorigenesis Through Oxidative Stress-related Pathways

Among the many mycotoxins, T-2 toxin, citrinin (CTN), patulin (PAT), aflatoxin B1 (AFB1) and ochratoxin A (OTA) are known to have the potential to induce dermal toxicity and/or tumorigenesis in rodent models. T-2 toxin, CTN, PAT and OTA induce apoptosis in mouse or rat skin. PAT, AFB1 and OTA have tumor initiating properties, and OTA is also a tumor promoter in mouse skin. This paper reviews the molecular mechanisms of dermal toxicity and tumorigenesis induced in rodent models by these mycotoxins especially from the viewpoint of oxidative stress-mediated pathways.     

Protection against progressive atrophic rhinitis by vaccination with Pasteurella multocida toxin purified by monoclonal antibodies

Pasteurella multocida toxin was purified by affinity chromatography and inactivated by treatment with formaldehyde before use as a single component vaccine against progressive atrophic rhinitis in pigs. Twenty pregnant gilts which were vaccinated twice before farrowing with either low or high doses of the purified toxoid, developed dose-dependent positive serum and colostrum titres to the toxin and, unlike the progeny of 10 untreated control gilts, the offspring of the vaccinated gilts also had serum titres. These titres could be measured in blood samples taken for more than eight weeks from birth for most pigs born to gilts vaccinated with low doses and more than 12 weeks for pigs born to gilts vaccinated with high doses of the vaccine. All the piglets were inoculated intranasally with Bordetella bronchiseptica and toxigenic P multocida. The clinical and post mortem examinations of snouts revealed a significant reduction in the frequency and degree of conchal atrophy in the two groups of pigs from the vaccinated gilts compared with the pigs from control gilts. Clinically 90 per cent of the snouts of pigs born to vaccinated gilts appeared normal whereas only 28 per cent of the snouts of control pigs were not shortened or deviated at eight weeks of age. At slaughter 11 per cent of the pigs born to vaccinated gilts and 81 per cent of the control pigs had severe turbinate atrophy.(ABSTRACT TRUNCATED AT 250 WORDS)     

A biological method for the determination of mycotoxins--Tetrahymena pyriformis

The toxic action of selected mycotoxins on a biological subject was tested in the protozoan Tetrahymena pyriformis. The following toxins were tested: toxin T-2 at doses from 1.52 micrograms to 100.0 mg per litre of medium, ochratoxin A at doses from 12.21 micrograms to 800.0 mg per litre of medium, and rubratoxin B at doses from 12.21 micrograms to 800.0 mg per litre of medium. In toxin T-2 the LD100 was found to be about 390.63 micrograms and LD50 about 48.83 micrograms per litre of medium. In ochratoxin A the LD100 was about 25.0 mg and LD50 about 3.13 mg per litre of medium. In rubratoxin B the LD100 was about 200.0 mg and LD50 about 25.0 mg per litre of medium.     

Porcine nephropathy induced by long-term ingestion of ochratoxin A.

Nine pigs were fed crystalline ochratoxin A in their feed at a concentration of about 1 mg/kg. Three pigs and their controls were killed after 3 months and 6 pigs and controls were killed after 2 years. A decrease of the ratio TmPAH/CIn, increased urinary glucose excretion and decreased ability to concentrate urine, occurred within a few weeks and aggravated slightly during the 2-year period. Changes in renal structure, characterized by degeneration and atrophy of proximal tubules, interstitial fibrosis and hyalinization of glomeruli, were progressive during time of exposure, but terminal renal failure was not reached. The kidney, liver, muscular and adipose tissue contained 3 to 27 microgram ochratoxin A/kg after 3 months of exposure. No further accumulation of ochratoxin A residue was found after 2 years of exposure.     

A Clostridium botulinum type B vaccine for prevention of shaker foal syndrome

A toxoid was prepared from type B toxin of Clostridium botulinum by treatment with 0.6% formalin for 6 weeks. The toxoid was adsorbed to aluminium hydroxide and this vaccine was evaluated for safety in guinea pigs, mice and horses, and for immunogenicity in guinea pigs and horses. Neutralising antitoxin was demonstrated in adult horses receiving two 2 ml subcutaneous doses 6 weeks apart, and in a foal which suckled its vaccinated dam. Another vaccinated mare and the passively immunised foal were protected against subcutaneous injection of 1600 and 2000 mouse lethal doses of toxin per kg respectively.     

Turbinate atrophy in gnotobiotic pigs intranasally inoculated with protein toxin isolated from type D Pasteurella multocida

Three doses (75 micrograms, 25 micrograms, and 25 micrograms) of purified toxin isolated from a toxigenic strain of type D Pasteurella multocida were given (by atomizer) into the right nasal cavities of each of 10 gnotobiotic pigs on the 21st, 24th, and 27th days of age, respectively. Inoculated pigs (usually 2) and 1 noninoculated control pig each were necropsied on 3, 6, 9, 12, and 15 days after inoculations were given. Severe bilateral atrophy of turbinates occurred in all toxin challenge-exposed pigs. Atrophy was more severe in the inoculated nasal cavity than that in the noninoculated side in 2 of the 10 pigs. Microscopic changes in turbinates of toxin challenge-exposed pigs were more severe in pigs killed at later dates. Dominant changes included degeneration and necrosis of osteoblasts, markedly accelerated osteoclastic osteolysis, replacement of the osseous core by a highly cellular mesenchymal stroma, and multifocal atrophy of submucosal glands. Seemingly, a protein toxin isolated from toxigenic type D strains of P multocida produced rapid atrophy of turbinates and may be a contributing factor in development of clinical progressive atrophic rhinitis in swine.     

Evaluation of diets contaminated with aflatoxin and ochratoxin fed to growing pigs

The effects of dietary aflatoxin and ochratoxin, fed singly and in combination, were evaluated in growing crossbred pigs. Five barrows (7 weeks old at beginning of study) per group were fed either control feed, 2.0 mg of aflatoxin (AF)/kg of feed, 2.0 mg of ochratoxin (OA/kg of feed, or 2.0 mg of AF and 2.0 mg of OA/kg of feed for 28 days. Production performance, serum biochemical, hematologic, and pathologic evaluations were made. Body weights were reduced by the combination treatment, whereas body weight gain was decreased by all toxin treatments. The effect of AF and OA in combination on body weight gain was additive. Liver weights were increased by the combination treatment, whereas kidney weights were increased only in the OA group. Aflatoxin caused decreases in serum calcium, sodium, phosphorus, urea nitrogen, cholesterol, and glucose concentrations, whereas OA alone caused decreases in serum phosphorus, cholesterol, and hematologic values. The AF-OA treatment induced decreases in mean corpuscular volume, packed cell volume, and in serum concentrations of phosphorus, cholesterol, and urea nitrogen. The AF-OA treatment increased serum alkaline phosphatase activities and triglycerides. It was concluded that AF and OA, singly or in combination, can affect clinical performance, serum biochemical and hematologic values, and organ weights of barrows. Although values of some measurements were affected more by the combination than by either toxin alone and suggested synergism or antagonism, the toxic interactions could best be described as additive.     

Hep atop athy and dermatitis in a dog associated with the ingestion of mycotoxins

A five-year-old German shepherd dog was presented with a severe scrotal dermatitis of four weeks duration which had failed to respond to antibiotic and corticosteroid therapy. Dermato-histopathology indicated that the lesion was a necrolytic process suggestive of the hepatocuta-neous syndrome. Clinical biochemistry investigations indicated the presence of acute hepatocellular damage and cholestasis. The animal was fed a biscuit meal which was damp and mouldy. Penicillium vindication was grown from this feedstuff and three mycotoxins, citrinin, ochratoxin A and sterigmatocystin, were found; substances which have been associated with renal and hepatic lesions in dogs and laboratory animals. Symptomatic therapy and nutritional management, led to rapid clinical improvement. Subsequent plasma biochemistry confirmed that hepatic enzyme activities were returning to normal levels.     

Characterization and immunogenicity of an apxIA mutant of Actinobacillus pleuropneumoniae

Actinobacillus pleuropneumoniae is the aetiological agent of porcine pleuropneumonia, a highly contagious and often fatal disease. A candidate live vaccine strain, potentially capable of cross-serovar protection, was constructed by deleting the section of the apxIA gene coding for the C-terminal segment of ApxI toxin of the A. pleuropneumoniae serovar 10 reference strain (D13039) and inserting a chloramphenicol resistance gene cassette. The mutant strain (termed D13039A(-)Chl(r)) produced an approximately 48kDa protein corresponding to the N-terminus of the ApxI toxin, and exhibited no haemolytic activity and lower virulence in mice compared with the parental strain. The mutant was evaluated in a vaccination-challenge trial in which pigs were given two intra-nasal doses of the mutant at 14 days intervals and then challenged 14 days after the last vaccination with either A. pleuropneumoniae serovar 1 (4074) or serovar 2 (S1536) or serovar 10 (D13039) reference strains. The haemolysin neutralisation titres of the pre-challenge sera were significantly higher in the vaccinated pigs than in the unvaccinated pigs. The mortalities, clinical signs and lung lesion scores in the vaccinated pigs were significantly lower than those in the unvaccinated pigs for the serovar 1 challenge. A significantly lower lung lesion score was also observed in the vaccinated pigs, compared with unvaccinated pigs, for serovar 2 challenge. Our work suggests that the mutant strain offers potential as a live attenuated pleuropneumonia vaccine that can provide cross-serovar protection.     

Effects of some clinically significant mycotoxins on the incorporation of DNA, RNA and protein precursors in cultured mammalian cells

The effects of zearalenone (F-2), ochratoxin A and T-2 toxins on the synthesis of DNA, RNA and proteins in mouse L cells were studied. F-2 toxin inhibited protein synthesis to a lesser extent than DNA and RNA synthesis, whereas ochratoxin A inhibited the synthesis of each equally. Exposure to the toxins for 24 hours relatively reduced the synthetic ability of the cells. T-2 toxin inhibited protein and DNA synthesis in parallel but RNA synthesis to a lesser extent. Enhanced incorporation of tritiated thymidine was found when L cells were exposed to 0.4 to 0.016 ng of T-2 toxin ml-1 for 24 hours.     

Mycotoxin interactions in poultry and swine

Mycotoxins are toxic compounds produced by fungi. When one mycotoxin is detected, one should suspect that others also are present in a contaminated feed ingredient or finished feeds. The toxicity and clinical signs of observed in animals when more than one mycotoxin is present in feed are complex and diverse. Some mycotoxins, such as the combination of aflatoxin with either ochratoxin A or T-2 toxin, interact to produce synergistic toxicity in broiler chicks. The effects observed during multiple mycotoxin exposure can differ greatly from the effects observed in animals exposed to a single mycotoxin. For example, fatty livers in poultry are used for presumptive diagnostic identification of aflatoxicosis. However, simultaneous presence of ochratoxin A prevents fatty livers. Of the mycotoxin combinations that have been investigated in poultry and swine, the aflatoxin + ochratoxin A and aflatoxin + T-2 toxin interactions appear to be the most toxic.     

16种植物性饲料原料中黄曲霉毒素B1、T-2毒素、赭曲霉毒素A、伏马毒素(B1+B2)污染调查检测及控制建议

为掌握黄曲霉毒素B1、T-2毒素、赭曲霉毒素A、伏马毒素(B1+B2)在植物性饲料原料中的污染状况,指导帮助饲料企业和养殖企业开展霉菌毒素防控,降低霉菌毒素对饲料产品质量及畜禽养殖产品危害,减少经济损失,2020年对16种60份植物性饲料原料进行调查采样,采用液相色谱—串联质谱法、免疫亲和柱净化—高效液相色谱法检测,依...     

The significance of the mycotoxins desoxynivalenol, zearalenone and ochratoxin A for agricultural domestic animals]

Mycotoxins are metabolic products of mycotoxins which have various chemical structures and show various toxic effects. Deoxynivalenol (vomitoxin) is an important economic factor in pig production due to growth depression and suppression of the immune system. Previous studies have shown that the 1-ppm limit in the sole feed for pigs should not be exceeded. Studies of methods of detoxification have as yet not produced conclusive results. Zearalenone has an tolerable effect and may lead to fertility disturbances on the oestrogen production in pigs and can cause remarkable economic damage even in the ppb range. Recommendations of upper limits cannot be made on the basis of the available results. The kidney toxin ochratoxin A is of importance in pig and poultry breeding and--due to its accumulation in the tissue--represents a possible source of danger to man. Since a possible carcinogenic effect of the toxin cannot be excluded, its content in animal rations should be kept as low as possible. For ruminants mycotoxins as a whole do not represent a particular source of danger as these substances can be degraded or converted by rumen flora.     

Tonsils--place of botulinum toxin production: results of routine laboratory diagnosis in farm animals

Since a case of a veterinarian was reported, who was likely to be infected/intoxicated by Clostridium botulinum during the handling of a diseased animal, tonsils in animals were tested for botulinum neurotoxin and bacterial forms of neurotoxic Clostridium botulinum during routine botulism laboratory examinations including standard samples (intestinal tract and liver) from 48 cattle, 11 horses, and 14 goats. Ten out of 60 samples from tonsils contained free botulinum toxin, and 12 out of 59 were positive for live toxin producing bacteria. In 32 out of 162 intestinal samples toxin was detected. Toxin producing bacteria were found in 37 samples. Eight of 56 liver samples contained free toxin, and 15 out of 43 toxigenic bacteria. Samples from 10 slaughter pigs were all negative, whereas from slaughter cattle tonsils had a high incidence of toxin (7 of 10) or toxigenic bacteria (2 of 8). The results are discussed in the context of effects on animal health and botulism as zoonosis.     

Host response to Pasteurella multocida turbinate atrophy toxin in swine.

A porcine strain of Pasteurella multocida (serotype D:3) produced a toxin causing turbinate atrophy (TA) in pigs. The toxin (TAT), processed on a high performance liquid chromatography size exclusion column, eluted as a single peak (molecular weight of about 160,000) containing trace amounts of endotoxin (lipopolysaccharide, LPS; protein:LPS, 85:1). The eluted fraction migrated on sodium dodecyl sulfate polyacrylamide gels as a single band. It could be prevented from dissociating into two prominent polypeptides by addition of a protease inhibitor. A single dose (2.0 to 79.0 micrograms/kg) of TAT given to pigs intravenously was lethal. Doses from 0.02 to 1.0 microgram/kg caused transient clinical signs of porcine systemic toxicosis with reduced appetite, generalized weakness, depression, lethargy, weight loss, and in some instances, death. Intradermal doses of TAT (greater than or equal to 0.1 microgram/site) produced hemorrhagic areas within four hours. Systemically, TAT causes bilateral TA, lymphopenia, liver dysfunctions, and possible renal impairment. Affinity of TAT for cells of epithelial origin was demonstrated in mice given 125I-TAT. In vitro, TAT stimulated DNA and protein syntheses of peripheral blood lymphocytes and suppressed syntheses in turbinate and kidney cell cultures without being cytolytic. Biological effects of TAT were eliminated by exposure to either heat, trypsin or anti-TAT antibody.