Conditions for the formation of mycotoxins in animal feed

The development of moulds and the production of mycotoxins are closely related, but the optima of environmental factors for both do not necessarily coincide. Depending on the species, the percentage of toxinogenic strains differs considerably. Complex substrates, with a high content of carbohydrates, are favoured. Over a wide range of temperature toxin-production is possible, also at a very low partial pressure of oxygen. Too few is known about the factors, which promote toxin-production in the field. There seems to be a dependence on the area, where the grain is grown, and on the weather during the year of cropping, but the influence of methods of plant production, fertilization, plant protection and choice of cultivars have to be investigated.     

The occurrence of mycotoxins in cereals and animal feed-stuffs

During the period 1976–1979, just over 4000 samples of animal feedstuffs comprising cereals, compound feeds, hay and silage were examined for moulds and mycotoxins. Examination was carried out in the course of routine advisory and investigational work undertaken by the Agricultural Development and Advisory Service (Ministry of Agriculture, Fisheries and Food) Microbiology Laboratories in England and Wales in connection with livestock health and production problems and defects in grain storage. Mouldy cereals, mostly invaded byPenicillium andAspergillus species, were often found contaminated with ochratoxin A (12.8% positive) and also with citrinin, sterigmatocystin and zearalenone to a lesser extent. Aflatoxin B1 was detected in barley which had been inadequately treated with propionic acid in 3 instances.Commerically-produced compound feedstuffs and protein concentrates were found to contain aflatoxin B1 at levels ranging from less than 10 to 750 g/kg due to the inclusion of contaminated constituents such as ground-nut, palm kernels, cottonseed and copra. There was no evidence that any significant spoilage byAspergillus flavus in compound feedstuffs after manufacture had led to the formation of aflatoxin.Mould spoilage of hay, as indicated by mould counts exceeding 100,000 per g, was common withAspergillus glaucus andPenicillium spp. frequently present, though mycotoxins were not detected, with the exception of sterigmatocystin in just one sample. Silage which had been exposed to air was frequently colonised byPaecilomyces species, giving rise to the formation of patulin in several samples. Despite the frequent detection of mycotoxins in animal feedingstuffs, there was rarely any conclusive evidence implicating them in causing impaired performance or disease in animals.     

Occurrence of mycotoxins in Polish animal feed in years 2006-2009

We performed a 4‐year survey (2006–2009, 1255 samples) of fungal secondary metabolites in feed material (cereal and corn grains) and feedstuffs (silages, mixed feeds). Five major mycotoxin groups were studied, including aflatoxins (AF), ochratoxin A (OTA), trichothecenes [deoxynivalenol (DON), nivalenol (NIV), T‐2 toxin, HT‐2 toxin], zearalenone (ZEA) and fumonisins (FUM). The metabolites were identified using HPLC methods with fluorescent, UV and MS/MS detection. Both immunoaffinity and SPE columns were used for sample preparation. In eleven samples, the concentration of several mycotoxins exceeded the recommended guidelines for feedstuffs. DON was detected at the highest concentration in the majority of analysed samples (cereal grains, silages and mixed feeds, maximum values ranged from 409 to 14 470 ng/g). Corn grains also contained other Fusarium toxins (FUM) at maximum levels ranging from 435 to 9409 ng/g. The highest average_positive concentration of the other trichothecenes (NIV, T‐2 and HT‐2 toxins) was <5.0–139 ng/g. ZEA was found at the highest concentration in corn grains and silages (maximum values ranging from 292 to 603 ng/g and 116 to 1150 ng/g, respectively). The highest average_positive concentration and the maximum level of OTA were detected in cereal grains (33.0 ng/g in 2009 and 760 ng/g in 2007, respectively). Less than 7% of the 557 samples were contaminated with AF at low levels (maximum of 0.61 ng/g). Our results support the need for further monitoring of mycotoxins in Polish feedstuffs and their components.     

霉菌毒素的危害及抗氧化剂对动物的保护作用

霉菌毒素对饲料和饲料原料的污染极其严重,对动物和人类的健康造成严重的危害。霉菌毒素因具有肝毒性、遗传毒性,对免疫功能具有抑制作用,从而引起动物和人类多种急慢性疾病,而造成机体氧化损伤是霉菌毒素对动物和人类产生毒副作用的主要机制之一。国内外研究表明,抗氧化剂的添加能有效地降低霉菌毒素对动物造成的影响。     

Implications of intensification of pastoral animal production on animal welfare

The intensification of pastoral animal production results from several major developments including increased forage production and utilisation, diet supplementation, breeding animals to increase milk, meat or wool production, and changes in management. The impact of increased intensification on welfare will differ across species and systems. More intensive-grazing systems and the feeding of novel forages will underpin all moves to intensification. More intensive grazing generally reduces opportunities for shade and shelter. Improved nutrition will generally benefit welfare but competition for available feed may cause increased social pressure. Increased flock and herd size will be associated with a reduction in the human:animal ratio and less time to observe individual animals. Remote monitoring of activity and health might counter this impact.

Intensification of dairy production will result in larger herds, more year-round milking, robotic milking, use of housing and yards year round, and total mixed-ration feeding. Larger herds mean longer distances to walk to and from the dairy shed, and more lameness and less time to spend on self-maintenance activities such as grooming. Holding and feeding dairy cows on yards will cause an increase in lameness and mastitis and perhaps an increase in agonistic behaviour but will reduce time spent walking. Intensification of sheep production will involve increased flock size, increased fecundity, breeding from hoggets, and breeding ewes all year round. Housing during lambing might be considered appropriate, as would feeding to lift milk yields. Increased fecundity with an increase in triplets will increase lamb mortality rates, but housing ewes, when managed well, will result in reduced lamb mortality. Intensification of lamb finishing will be by improved nutrition. Intensification of beef production will include more breeding of heifers at 15 months, and more problems with dystocia.

Intensification of pastoral production will have positive and negative effects on animal welfare. The balance will be determined by the quality of management and stockmanship, and the pressure on businesses to be profitable.     

Association between forage mycotoxins and liver disease in horses

BackgroundOutbreaks of liver disease in horses are common but the etiology of most remains unknown. Forage mycotoxins have been suspected to be a cause.ObjectivesTo examine the association between outbreaks of liver disease and the presence of mycotoxins in forage stored on the same premises.AnimalsPremises were identified where ≥4 horses were contemporaneously affected by liver disease, and a control group was formed from premises where ≥4 horses had been examined and found to have no evidence of liver disease.MethodsForage was collected from 29 case and 12 control premises. The forage was analyzed for mycotoxin content using a liquid chromatography/mass spectrometry method, targeting 54 mycotoxins. The presence and distribution of mycotoxins between case and control samples was compared.ResultsMycotoxins were found in 23/29 (79%) case samples and 10/12 (83%) control samples (P > .99; relative risk, 0.93; 95% confidence interval [CI], 0.64‐1.75). Median (interquartile range [IQR]) total mycotoxin concentration was similar in case and control samples (85.8 μg/kg [1.6‐268] vs. 315 μg/kg [6.3‐860]; P = .16). Ten mycotoxins were found exclusively in case premises comprising fumonisin B1, 15‐acetyldeoxynivalenol, deoxynivalenol, zearalenone, aflatoxins B1 and G1, methylergonovine, nivalenol, verruculogen, and wortmannin. The median (IQR) concentration of fumonisin B1 was significantly higher in case versus control samples (0 μg/kg [0‐81.7] vs. 0 μg/kg [0‐0]; P = .04).Conclusions and Clinical ImportanceSeveral mycotoxins with known hepatotoxic potential were found, alone or in combination, exclusively at case premises, consistent with the hypothesis that forage‐associated mycotoxicosis may be a cause of outbreaks of liver disease in horses in the United Kingdom.     

EM在防治动物疾病中的应用

EM是日本琉球大学比嘉照夫教授于20世纪80年代研制出的一种新型复合微生物制剂,含有5科10属80多种有益微生物。EM广泛应用于种植业、养殖业和环境污染治理,在促进动物     

Evaluation of brine shrimp (Artemia salina) larvae as a bioassay for mycotoxins in animal feedstuffs.

Brine shrimp larvae was tested as a possible simple biological screening system to identify specimens of animal feedstuffs that should be examined further by chemical analytical procedures for mycotoxins. All extracts of the control, nonmouldy feedstuffs increased larval mortality, this being most marked in the case of silage. Chemical and biological testing of diagnostic specimens indicated that the bioassay identified two of four chemically positive specimens and 59 of 135 chemically negative specimens and 59 identified larvicidal compounds present in normal feedstuffs gave a high percentage (56%) of false-positive bioassay results when compared to the results of chemical analyses for three mycotoxins. The use of brine shrimp larvae did not materially reduce the necessity of conducting chemical analyses for mycotoxins.     

Incidence of molds and mycotoxins in commercial animal feed mills in seven midwestern states, 1988-1989.

A total of 82 feed manufacturers located within seven midwestern states (Iowa, Nebraska, Minnesota, Illinois, Indiana, Ohio, Michigan) participated in a survey of mold and mycotoxin contamination of corn. Samples were submitted from a composite of the grading samples taken from each incoming load of corn. The survey was initiated in July 1988. During the 12-mo period, moisture content of the corn samples upon receipt at the laboratory ranged from 10.5 to 13.3%. The greatest variation occurred in the springtime. Iowa's corn samples were driest (11.2%), and samples submitted from Ohio were wettest (12.8%). Mold counts averaged 2.63 x 10(4) per gram during the year. The predominant mold found was Fusarium sp. Samples were checked by black light and averaged 25.4% positive during the period. When assayed for mycotoxins, 19.5% of the samples were positive for at least one of the following: aflatoxin, zearalenone, T2 toxin and deoxynivalenol (vomitoxin). Aflatoxin and T2 toxin made up the majority of these samples containing toxin. The highest incidence of mycotoxin-contaminated corn (48%) occurred in samples submitted in July of 1988. Over the 12-mo period, the highest mycotoxin contamination occurred in Iowa, Illinois and Michigan. When samples were subjected to 90% relative humidity and 32 degrees C, an average of 3.9 d was required for mold growth to appear. After incubation, 24.7% of the samples contained one of the four toxins. The data indicate that mold and mycotoxin contamination of mixed samples of corn is widespread, even in the midwestern corn belt of the U.S.     

动物治病有妙招

珍爱生命、自救生命是地球上一切有呼吸生物的本能。许多动物生病后出于本能的需要,不仅会借风使船,向异类求医问药,而且还会巧妙地利用一些植物的药用功能为自己治病。据科学家观察发现,非洲的黑猴、人猿,巴西雨林中的猕猴,当出现嗜睡、食欲不振、大便不畅的症状时,它们就会到一个特殊的地方,在那里找到一种向日葵,将它的嫩叶吞咽下肚,但它们从不将这当做正餐吃。研究表明,这种向日葵的叶子里含有一种红色油状物质,能杀死动物肠道内的寄生虫和真菌。美国生物学家曾经发现,一头怀孕母象走了28公里后,停在了一棵紫草科小树边,它把整棵树的枝…     

Import risk analysis in animal disease control

At the Swiss Federal Veterinary Office risk analyses are conducted according to international standards. A risk analysis contains the elements risk management, risk assessment and risk communication. A risk assessment is based on risk profile, hazard identification and a pathway model. All available information is gathered, documented and assessed and the risk estimated. The question. "What is the probability that unprocessed wild boar meat imported to Switzerland from the federal state Mecklenburg Western Pommerania is contaminated with classical swine fever virus?" was answered by a release assessment. The hazard identification recognized classical swine fever virus and attenuated live virus vaccine used for oral immunization as hazards. The probability of contamination was estimated to be small. The question: "What is the likelihood to introduce Aujeszky's disease to Switzerland and infect the indigenous pig population with the disease, by means of importing pork and meat products?" was answered by assessing the release, exposure and resulting consequences. The risk of an infection of the indigenous pig population was estimated to be very small, as 80% of the imported products derive from countries or zones free from Aujeszky's disease. Furthermore the majority of the imported products are processed. The strict implementation of the regulations governing feeding of food wastes to pigs reduces the probability of exposure. In all assessments the risk management decides on a strategy to deal with the risk, taking into consideration the results and recommendations derived from the risk assessment as well as other relevant factors.