Aflatoxicosis in Iowa swine: eight cases (1983-1985)

During 1983, 1984, and 1985, aflatoxicosis was diagnosed in 8 Iowa swine herds after the herds were fed corn from the 1983 corn crop. As a result of the diagnosis, the associated environmental conditions, clinical signs of aflatoxicosis, macroscopic and microscopic lesions, aflatoxin concentrations detected in feeds, and management of affected swine were reviewed. Concentrations of aflatoxin in shelled corn and complete feed were as high as 2,020 ng and 1,200 ng of aflatoxin (B1 and B2)/g of feed, respectively. Clinical signs of aflatoxicosis included decreased feed consumption and weight loss. Some pigs died acutely, but death often was preceded by a period of clinical disease. Greater morbidity and mortality were observed in swine herds that consumed greater concentrations of aflatoxin.     

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.     

Mycotoxins.

Horses consume feed grains and forages that can produce a range of mycotoxins resulting from mold invasion. Toxicosis of horses often occurs from fumonisins or aflatoxin in grains, from the tremorgenic mycotoxins in dallis grass, or from slaframine in red clover. Fumonisin toxicosis often is severe and fatal, and aflatoxin can be acute or chronic and debilitating. Other mycotoxins reported in horses may cause moderate to mild signs that regress when the contaminated feedstuff is removed. Overall, horses appear to have a relatively low prevalence of reported mycotoxicoses among domestic animals, but they are extremely sensitive to the fumonisins. Since there are no good therapies for mycotoxin poisoning, attention to providing high quality grains and forages to prevent mycotoxicoses is the most effective means for reducing the risk of mycotoxins in horses.     

Aflatoxicosis in nine dogs after exposure to contaminated commercial dog food.

The purpose of this study was to characterize light and electron microscopic findings from 9 dogs that had consumed aflatoxin-contaminated commercial dog food from recalled batches. Four dogs died and 5 were euthanized after signs of liver failure. Analysis of feed and liver samples confirmed exposure to aflatoxin. Of the 9 dogs, 8 had classic signs of liver failure, and 1 had signs of liver failure. Enlarged, pale yellow livers were seen macroscopically at necropsy in the dogs with subacute hepatopathy, and cirrhosis was noted in the dog with chronic hepatopathy. Histopathologic findings included hepatic lipidosis, portal fibroplasia, and biliary hyperplasia, which supported a diagnosis of subacute toxic hepatopathy in the 8 symptomatic animals. Marked lobular atrophy, bridging portal fibrosis, and regenerative hepatocellular nodules characterized the dog with chronic hepatopathy. Electron microscopy revealed marked hepatocellular lipid vacuolation and early fibroplasia in the dogs with acute hepatopathy and marked fibrosis and regeneration in the dog with chronic hepatopathy. Analysis of feed for aflatoxin consistently revealed high levels of aflatoxin B1 (range of 223-579 ppb), and hepatic tissue contained elevated levels of aflatoxin B1 metabolite M1 (0.6-4.4 ppb). Although dogs are not commonly affected by aflatoxicosis, they are highly susceptible and can present with classic signs of acute or chronic hepatopathy. Characteristic gross, histologic, and electron microscopic changes help pathologists determine a presumptive toxic insult. Detecting aflatoxins or their metabolites in feed or liver specimens can help confirm the diagnosis of aflatoxicosis.     

Molds, mycotoxins, and mycotoxicosis

Interest in mycotoxins and mycotoxicosis in humans and animals has greatly increased in recent years. Horses have long been considered very susceptible to molds. The signs, treatment, and prevention of several conditions, such as leukoencephalomalacia, aflatoxicosis, ergotism, fescue toxicity, slobbering disease, ryegrass staggers, and moldy sweet clover disease, are discussed.     

Aflatoxicosis in farm animals

Under conditions presently prevailing in the UK aflatoxicosis in farm animals, as defined in this paper, is largely confined to cattle but acute and chronic clinical liver disease is seldom if ever encountered. There is circumstantial evidence for sub-clinical and non-specific aflatoxicosis but dose-effect relationships have yet to be established, particularly at lower levels of dietary aflatoxin contamination.     

Interaction between Eimeria uzura infection and aflatoxicosis in Japanese quail (Coturnix coturnix japonica)

The clinical signs and gross lesions caused by Eimeria uzura (10(5) oocysts) in Japanese quail (Coturnix coturnix japonica) exhibited little or no influence in the face of intercurrent dietary aflatoxicosis (1 p.p.m. of aflatoxin B1 from Day 0 to 55). Similarly, no significant differences in the mucosal morphology of the intestine were evident histologically between the two groups of Japanese quail. The nervous signs of ataxia, leg weakness, incoordination of movement, torticollis and terminal opisthotonos were toxin-induced manifestations. In the aflatoxic quail, hypoplastic changes and selective depletion of lymphocytes were more prominent in the bursa of fabricius. Increased relative mean weights of liver, kidney, spleen, crop, proventriculus and gizzard were observed in birds due to aflatoxin sensitivity. The combination of E. uzura infection and aflatoxicosis in Japanese quail may cause significant weight loss, and increased oocyst production and reproductive potential.     

Effects of various treatments on induced chronic aflatoxicosis in rabbits

Male New Zealand White rabbits were orally given 0.05 mg of aflatoxin B1 (AFB1)/kg of body weight daily for 10 days and were treated with glutathione-precursors and depletor, antibacterial agents, or sodium thiosulfate. The drug administered, the mortality, and the mean survival time were as follows: corn-oil controls (0), euthanatized at 25 days; AFB1-controls (2), 21 days; AFB1 and saline controls (2), 22 days; cysteine and AFB1 (5), 13 days; methionine and AFB1 (5), 12 days; sodium thiosulfate and AFB1 (2), 21 days; sulfadimethoxine and AFB1 (1), 24 days; oxytetracycline and AFB1 (0), euthanatized at 25 days; and ethyl maleate and AFB1 (3), 21 days. Clinical signs of toxicosis included decreased feed consumption during AFB1 administration, loss of body weight or failure to gain, and death. Clinicopathologic changes included increases in serum bilirubin concentration and alanine aminotransferase and aspartate aminotransferase activities. Prothrombin and activated partial thromboplastin times were lengthened. Plasma fibrinogen concentration was decreased. Changes in PCV, hemoglobin concentration, and serum alkaline phosphatase were unremarkable. Oxytetracycline had protective effects against chronic aflatoxicosis in rabbits. Cysteine and methionine enhanced chronic aflatoxicosis.     

黄曲霉毒素及其解毒剂在畜禽营养上的研究进展

黄曲霉毒素是畜禽饲料中危害最严重的生物类毒素,作者综述了黄曲霉毒素在畜禽体内的代谢及其对畜禽生长性能、抗氧化系统、免疫系统和肝脏的毒性作用,并介绍了物理吸附类、化学反应类、生物降解类和联合应用类黄曲霉毒素解毒剂及其作用效果,为饲料行业研究如何避免黄曲霉毒素污染提供参考。     

Protective effect of L-carnitine against oxidative damage caused by experimental chronic aflatoxicosis in quail (Coturnix coturnix)

This study was designed to evaluate the effect of L-carnitine supplementation on the plasma malondialdehyde (MDA) and whole blood reduced glutathione (GSH) concentrations in experimentally-induced chronic aflatoxicosis in quails. For this purpose, a total of 80 quails up to 8 weeks old were divided into four equal groups. Group I served as control, Group II was given L-carnitine at the dose of 200 mg/litre in the drinking water for 60 days, Group III was given 60 microg total aflatoxin/kg diet for 60 days, and Group IV was given both 60 microg total aflatoxin/kg diet and 200 mg L-carnitine/litre in the drinking water for 60 days. Aflatoxin treatment caused a significant increase in plasma MDA and a significant decrease in blood GSH concentrations. On the other hand, there was a significant decrease in plasma MDA and a significant increase in whole blood GSH in the L-carnitine-supplemented group. The present study demonstrated that L-carnitine brought about the inhibition of lipid peroxidation by enhancing antioxidant capacity in quails with chronic aflatoxicosis.     

Mycotoxins and the intestine

Fungal biochemical pathways can yield various compounds that are not considered to be necessary for their growth and are thus referred to as secondary metabolites. These compounds have been found to have wide ranging biological effects and include potent poisons(mycotoxins). Mycotoxins invariably contaminate crops and(thus) animal feeds. The intestine is the key link between ingested mycotoxins and their detrimental effects on the animal. Effects on the intestine, or intestinal environment, and immune system have been reported with various mycotoxins. These effects are almost certainly occurring across species. Most, if not all, of the reported effects of mycotoxins are negative in terms of intestinal health, for example, decreased intestinal cell viability, reductions in short chain fatty acid(SCFA)concentrations and elimination of beneficial bacteria, increased expression of genes involved in promoting inflammation and counteracting oxidative stress. This challenge to intestinal health will predispose the animal to intestinal(and systemic) infections and impair efficient digestion and absorption of nutrients, with the associated effect on animal productivity.     

An overview of aflatoxicosis of poultry: its characteristics, prevention and reduction

Aflatoxicosis represents one of the serious diseases of poultry, livestock and other animals. The cause of this disease in poultry and other food-producing animals has been attributed to the ingestion of various feeds contaminated with A. flavus. This toxigenic fungus is known to produce a group of extremely toxic metabolites, of which aflatoxin B1 (AFB1) is most potent. Avian species especially chicks, goslings, ducklings and turkey poults are most susceptible to AFB1 toxicity. The toxic effects of AFB1 are mainly localized in liver as manifested by hepatic necrosis, bile duct proliferation, icterus and hemorrhage. Chronic toxicity in those birds is characterized by loss of weight, decline in feed efficiency, drop in egg production and increased susceptibility to infections. The incidence of hepatocellular tumors, particularly in ducklings, is considered to be one of the serious consequences of aflatoxicosis. Even though prevention and avoidance are the best way to control aflatoxicosis, natural contamination of crops with A. flavus is sometimes unavoidable. Such aflatoxin-contaminated feeds can be decontaminated using various methods which mainly focus on physical removal or chemical inactivation of the toxins in the feeds. Moreover, dietary additives such as activated charcoal, phenobarbital, cysteine, glutathione, betacarotene, fisetin and selenium have also been reported to be effective in the reduction of aflatoxicosis in poultry.     

An overview of aflatoxicosis of poultry: Its characteristics,prevention and reduction

Aflatoxicosis represents one of the serous diseases of poultry, livestock and other animals. The cause of this disease in poultry and other food-producting animals has been attributed to the ingestion of various feeds contaminated with A. flavus. This toxigenic fungus is known to produce a group of extremely toxic metabolites, of which aflatoxin B₁ (AFB₁) is most potent. Avian species especially chickes, goslings, ducklings and turkey poults are most susceptible to AFB₁ toxicity. The toxic effects of AFB₁ are mainly localized in liver as manifested by hepatic necrosis, bile duct proliferation, icterus and hemorrhage. Chronic toxicity in those birds is characterized by loss of weight, decline in feed efficiency, drop in egg production and increased susceptibility to infections. The incidence of hepatocellular tumors, particularly in ducklings, is considered to be one of the serious consequences of aflatoxicosis. Even though prevention and avoidanve are the best way to control aflatoxicosis, natural contamination of crops with A. flavus is sometimes unavoidable. Such aflatoxin-contaminated feeds can be decontaminated using various methods which mainly focus on physical removal or chemical inactivation of the toxins in the feeds. Moreover, dietary additives such as activated charcoal, phenobarbital, cysteine, glutathione, betacarotene, fisetin and selenium have also been reported to be effective in the reduction of aflatoxicosis in poultry.     

Effect of aflatoxin on performance, hematology, and clinical immunology in lambs.

Twenty-four female lambs were intoxicated with a diet contaminated with 2 ppm aflatoxin for a period of 37 d. Twelve lambs were maintained as the control group. After this period, the lambs were left for 35 d without aflatoxin in their feed. Performance, hematology and clinical immunology were examined in the intoxicated lambs. A non-significant decrease in body weight was observed in the intoxicated lambs during the intoxication period, whereas a significant decrease (P<0.001) in average daily gain was noted on the last day of intoxication and during the clearance period. No significant differences were observed in erythrocyte count, white blood cell count or differential leukocyte count between the groups. Bacteriostatic activity of the serum was lower in the intoxicated lambs, however, there was no effect on serum opsonic activity. Phagocytosis by the neutrophils was higher during the intoxication period and the levels of IgG were elevated in the intoxicated lambs. In vivo cellular immunity was assessed by intradermal injection of phytohemagglutinin; the response was lower during intoxication period. These results indicate that a lowering in the average daily gain was the most sensitive indicator of aflatoxicosis in lambs, and that the immune response was altered, which could render the animals more susceptible to infectious diseases.     

饲料中的霉菌毒素及其防制措施

霉菌毒素是由真菌或霉菌产生的次级代谢产物,在动物体中,霉菌毒素的毒性是慢性的,很少引起动物死亡。但是霉菌毒素的存在降低了饲料的营养价值,以及动物的生产性能,从而影响生产力,且霉菌毒素在畜产品(肉、奶等)中的残留会给人类健康带来严重威胁。作者主要介绍了饲料中常见的霉菌毒素(黄曲霉毒素、赭曲霉毒素、玉米赤霉烯酮、脱氧雪腐镰刀菌烯醇、T-2毒素、伏马菌素等),以及其毒性和危害,并从预防与去毒两个方面,阐述了霉菌毒素的防制措施,进而减少霉菌毒素造成的危害。     

牛奶中霉菌毒素来源、转化及危害

霉菌毒素污染是牛奶质量安全的主要风险之一,其种类主要包括黄曲霉毒素(AFs)、赭曲霉毒素(OTs)、玉米赤霉烯酮(ZEA)、伏马毒素(FUM)、脱氧雪腐镰刀菌烯醇(DON)、T-2毒素(T-2)等。牛奶中的霉菌毒素主要来源于动物饲料,本文在国内外已有文献报道基础上,对牛奶中霉菌毒素来源、转化以及危害、限量进行综述。     

黄曲霉毒素及其致病机理简述

针对蒙牛牛奶产品中检出黄曲霉毒素的问题,本文从黄曲霉毒素的分子结构、理化性质、污染途径和程度、致病机理和限量标准及快速检测等方面做了简述。同时对牛的黄曲霉毒素中毒提出了防治的具体措施。     

Effects of aflatoxin ingestion on the development of Moraxella bovis infectious bovine keratoconjunctivitis

A study was conducted to determine whether measured doses of aflatoxin given under different schedules would influence the pathogenesis of Moraxella bovis induced infectious bovine keratoconjunctivitis (IBK). Calves were allotted to 4 groups (groups I-IV) of 9, 9, 9, and 8 calves, respectively. Group I calves were given aflatoxin for 11 consecutive days starting 5 days before their eyes were exposed to M. bovis. Group II calves were given aflatoxin for 5 consecutive days starting 7 days after their eyes were exposed to M. bovis. Group III calves were given aflatoxin for 5 consecutive days starting 21 days after their eyes were exposed to M. bovis. Group IV calves were not given aflatoxin; but their eyes were exposed to M. bovis on the same day as were the eyes of calves in groups I-III; these calves served as controls. Aflatoxin had little if any influence on the pathogenesis of IBK under the conditions of this study. The results did not rule out an exacerbating effect of M bovis infection on aflatoxicosis in calves. Calves with the highest concentration of aflatoxin in their blood had the more severe signs of aflatoxicosis. Possible reasons for the equivocal results are discussed.     

霉菌毒素对畜禽的危害及削减方法研究进展

霉菌毒素是由不同种属真菌产生的次级代谢物,其对多种动物（包括人在内）具有显著毒性效果,如降低畜禽生产性能、损害脏器功能、影响机体免疫功能、造成细胞和DNA氧化损伤,甚至导致动物死亡等。饲料及其原料霉菌毒素污染是一个广泛的、全球性的问题,既可在作物田间生长时产生,也可在仓储期间产生,给畜禽养殖业造成了巨大的经济损失,防控霉菌生长及去除饲料中霉菌毒素已成为国内外研究的热点。实际上,不同霉菌毒素对不同动物的损害具有差异性,而在畜禽养殖过程中添加适当物质（如蒙脱石和酶制剂等）可有效抑制霉菌毒素活性,缓解霉菌毒素的毒性。作者详细论述了玉米赤霉烯酮、烟曲霉毒素、呕吐毒素、T-2毒素、黄曲霉毒素和烟曲霉毒素对畜禽的危害,并从物理、化学、生物角度介绍了削减饲料及其原料中霉菌毒素的方法,旨在为合理有效防控霉菌毒素毒害及保障畜禽健康养殖提供参考。     

Aflatoxin in a Swedish grain sample

So far aflatoxin has not been detected in crops grown in Sweden but only in imported feedstuffs or in feed mixtures containing imported products. During the survey for other mycotoxins in Swedish crops a compound was detected in oats which, by further analysis, was identified as aflatoxin B1. Quantitative evaluation showed concentrations as high as 2.6 ppm. The fungal population in this highly contaminated sample consisted almost entirely of Aspergillus flavus.