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霉菌毒素污染不單純表現(xiàn)在飼料上，通風不良雞舍的空氣污染，長時間清刷飲水器的污染等，而雞群中毒的反應與程度差異又很大，通常會導致雞群多種難以判斷的綜合癥狀，還導致雞群生產性能下降，免疫機能抑制，抵抗力下降就會疾病多發(fā)，而且在臨床上由于霉菌毒素隱形的感染，加大了其他疾病治療的難度，因此這就需要我們加深這方面的認知。
重視霉菌毒素在養(yǎng)雞生產中的危害。
一般的說，霉菌毒素中毒有急性與隱性之分。急性中毒有明顯的臨床癥狀，但發(fā)生最多的，人們最容易忽略或難以察覺的則是隱性中毒。要知道隱性中毒所造成的經濟損失遠比急性中毒要大得多。在急性中毒的病例中，以黃曲霉毒素中毒為最。
隱性中毒主要有以下幾個危害層面：
一、對飼料及原料質量的破壞。
孢霉菌屬于一種腐生微生物，靠分解、消耗飼料養(yǎng)分生長繁殖，還釋放熱量，使料溫升高，其結果是飼料中蛋白質變質，利用率降低，氨基酸含量下降，還會使脂肪、維生素發(fā)生變化，這樣一來，按照科學組方設計的全價料，勢必變成并不全價以至“殘價的料，而飼料在生產、運輸、倉儲、使用過程中的被氧化及細菌感染，又給霉菌滋生提供了有利條件，導致更多的霉菌毒素產生。此時，飼料及原料的營養(yǎng)濃度已經大打折扣。
二、飼養(yǎng)管理不良情況下的低標準量中毒。
如：高溫、通風差、擁擠、糞便清理不及時、免疫反應過強、營養(yǎng)失衡、疾病等會導致畜禽對霉菌毒素的抵抗力下降。由于霉菌毒素是小分子化合物，機體對其不產生抗體，因此，管理不良所致的應激，會使即便是低于危害標準的毒素也會引發(fā)動物機體中毒。
三、對畜禽消化道黏膜的強腐蝕性。
會形成鴨雛口腔潰瘍，食道炎，雞和其他動物的腸粘膜脫落、壞死，從而影響機體對營養(yǎng)物質的消化、吸收。例如：會造成VE和硫胺素吸收不良，從而導致免疫力下降和神經癥狀，又會使腸道形成對色素吸收障礙，引起喙和爪著色不良。
腸道除了是消化器官外又是機體重要的免疫器官之一，其功能是誘導機體對微生物類的抗原發(fā)動先天性與獲得性免疫反應，腸道同時也吸收霉菌毒素，當霉菌毒素嚴重破壞了腸道上皮細胞的完整性時，免疫球蛋白的分泌會降低，而免疫球蛋白在腸粘膜的免疫應答中起著至關重要的作用，霉菌毒素的毒性抑制了蛋白質的合成，腸道免疫系統(tǒng)的被破壞會致家禽對傳染病的易感性更高了。
四、對肝臟的破壞，造成肝細胞壞死，充血后期形成“橡皮肝 。
肝臟有儲備糖原的功能，糖原減少，發(fā)生低血糖癥，往往飲葡萄糖無效;還會干擾肝臟卵黃前體的合成和運輸，進而造成產蛋率下降和產小蛋增多。
五、對腎臟的損傷。
可致腎腫、痛風、軟骨組織發(fā)育不良，畜禽腿病發(fā)病率升高。
六、對血管壁的損傷。
使畜禽血壓升高，加重心臟負擔和臟器組織滲透壓升高，誘發(fā)腹水癥。
七、對免疫器官的損傷。
除如前所述對腸道免疫系統(tǒng)的破壞外，尤其會造成雞胸腺、法氏囊的萎縮，T淋巴細胞和白細胞減少，白蛋白和球蛋白含量降低，抗體效價下降，血清抗體濃度降低，引起免疫抑制而使各種病毒病多發(fā)。
免疫失敗常被認為是疫苗質量，接種過程失誤，強毒攻擊或其他復雜因素影響，而霉菌毒素造成免疫失敗，卻常被忽視，很多病在正常免疫后發(fā)生，以至于對健康畜禽本不具備感染力的病原也會因霉菌毒素中毒而引發(fā)條件性病原感染。有人認為，大量用疫苗后抗體仍達不到應有滴度，很可能與霉菌毒素有關。
八、種雞采食了被黃曲霉毒素污染的日糧所產后代雛雞對疾病的易感性增加免疫機能差。
據測定，這種雞雛在進行新城疫傳支常規(guī)免疫后其血清抗體滴度顯著低于正常雞水平。而侵入種蛋中的霉菌毒素會導致雞鴨等禽類孵化死胎率升高，后代幼雛肌胃先天性損傷，促使腸道病早發(fā)，并出現(xiàn)生長障礙，此種情況極易與雞傳貧與呼腸孤感染相混。
隱性中毒多呈慢性經過且臨床表現(xiàn)不盡相同，多為繼發(fā)癥而非毒素中毒的特定癥，這就使得許多時候是以別種病癥的診斷來治療本病。
例如：有些霉菌毒素對蛋雞生產性能的抑制，在開始的短時間內體現(xiàn)不出來，隨著時間推移體內毒素作用積累增多，到中期開始表現(xiàn)直至后期。
曾有一例蛋雞，在中毒后的發(fā)病前期，采食由細慢、叨料到逐漸減少，后發(fā)展為拒食而產蛋還在上升，至高峰維持25天后才開始下降。
據分析，這是因為此批雞育雛育成良好，又正處于產蛋上升期，生殖機能旺盛，而營養(yǎng)的負平衡是在25天后才顯現(xiàn)出來，這種表面現(xiàn)象很容易誤導診斷，
又如：新生雛雞1日齡即有明顯呼吸道癥狀，僅10%有肺霉斑變化，這就容易誤診為支原體病，發(fā)病于4日齡后的雛雞，往往生長不良、采食少、體重輕，會被認為是弱雛，霉菌毒素中毒還會使15日齡小公雞出現(xiàn)打鳴，雞冠發(fā)育過度，這主要是過量玉米赤霉烯酮引起，會被誤認為發(fā)育早。
再如：赭曲霉毒素中毒主要是腎損傷，表現(xiàn)為利尿作用加強，此時，雞群多尿脫水，由于利尿水泄，蛋雞拉稀久治不愈，產蛋下降，肉仔雞生長緩慢，貧血，形成佝僂癥。家畜則出現(xiàn)消化紊亂、采食下降、被毛粗亂、母畜流產、不發(fā)情、公畜死精等免疫力低下的還會出現(xiàn)無名高熱。
這些表面癥狀極易干擾臨床確診。因此，在養(yǎng)殖生產實踐和獸醫(yī)臨床診斷中，要對霉菌和霉菌毒素的危害有足夠的認識，在綜合分析中要加入這方面的因素，要關注和積累這方面的經驗，對疑似病例要盡可能借助設備手段以提高確診率，如：病料壓片鏡檢、病料接種培養(yǎng)，這在一般實驗室都能做;也可進行生物學鑒定，如：采用可疑病料作動物發(fā)病試驗，具備相應條件的可采用雛鴨法，這是世界法定通用的方法。
選用1日齡的雛鴨，通過胃管喂給毒素，飼養(yǎng)6-7天后，根據剖檢其膽管上皮細胞異常增生的程度來判定，也可取雛鴨肝組織作組織學檢查。
對可疑飼料及原料可采用化學分析法進行標準對照測定，也可用把樣品放在紫外燈下觀察熒光色澤來直觀判定，但這需要足夠的經驗。
由于目前尚無治療霉菌與霉菌毒素的特效藥，常規(guī)治療要配合進行，例如：用制霉菌素、克霉唑的同時在飼料中額外添加能夠促進肝臟解毒功能的營養(yǎng)成分，復合VB、蛋氨酸可幫助畜禽加速代謝，排出毒素，VA、VC、VE、硒會緩解霉菌毒素對機體細胞的毒性作用。
用氧化酶制劑可減少毒素在體內的吸收，氧化酶還可破壞毒素分子結構，降低毒素的有害毒性，并能明顯促進中毒臟器的排毒、解毒。
一般書刊介紹碘化鉀或硫酸銅溶液飲水治療本病，據實驗室檢測，要有較高濃度才有抑菌作用，通常1：3000硫酸銅飲水連用3天，臨床應用效果不一，有待進一步驗證。
堅持預防為主是解除霉菌和霉菌毒素危害的根本。飼料存放要干燥通風，存放期要短。不喂發(fā)霉飼料，及時更換發(fā)霉墊料，不要圖省事，一次添加全天的飼喂量，這在高溫高濕的舍內環(huán)境中，極易滋生霉菌。畜禽舍要充分通風排濕，飲具用品要洗刷干凈，放日光下照射4小時以上，育雛室、孵化室要用甲醛、過氧乙酸消毒，雞群添換水操作要避免隨地灑水，要控制好舍內溫濕度。
飼料廠和養(yǎng)殖戶自配料，可在新玉米中添加丙酸，以殺滅霉菌，但丙酸對霉菌毒素則沒有任何破壞作用，添加一些高效霉吸附劑、分解劑也能起到預防作用，尤其是使用玉米酒糟的飼料，更要注意添加，因為加工一噸玉米可產生約300斤的玉米酒糟，這些酒糟中會濃縮等于三倍量的霉菌毒素。
而用干玉米與新玉米兌摻配料，可以稀釋霉菌毒素濃度，只要濃度不超標，就不會有太多危害，況且雞群對霉菌毒素的敏感程度與日齡成反比，日齡越大的雞，耐受力較強，而小雞對霉菌毒素的耐受力低且后繼影響更大，這在飼喂中可關注區(qū)別對待。
在飼料廠的顆粒料生產過程中，要注意粉碎料入機前更易吸收周圍水分，堆壓時間過長，倉儲通風不良、雨淋、曝曬等都易引發(fā)霉菌污染，粉料入機后要調控好蒸氣壓、水分、時間，還要避免管道冷凝水進入而使粉料水分超標，出機時顆粒料溫度、水分過高，也會導致黃曲霉菌生長，還要定期清理顆粒料提升斗或管道中形成的霉積料。
總之，霉菌病和霉菌毒素中毒癥的防治是一個動態(tài)的連續(xù)過程，只有各個環(huán)節(jié)協(xié)同動作，才能收到較好的實效。
The English version
Mycotoxin contamination is not simply turning on the feed, poorly ventilated henhouse of air pollution, for a long time of flush water pollution and so on, and the crowd reaction of poisoning and the degree of difference is very big, again usually cause chickens a variety of difficult to judge the comprehensive symptoms, also led to the decrease of the chicken group production performance, immune function, resistance drop will disease happens, and infection in clinic because of mycotoxin invisible, even more difficult for other diseases, so we must deepen the cognition.
Pay more attention to the hazard of mycotoxins in poultry production.
General said that the mold toxin poisoning with acute and recessive. Acute poisoning has obvious clinical symptoms, but most, the most easy to ignore or imperceptible is recessive poisoning. Want to know the recessive poisoning caused by the economic loss is much larger than acute poisoning. In cases of acute poisoning, most for aflatoxin poisoning.
The recessive poisoning mainly has the following hazard level:
A, damage to the quality of feed and raw materials.
Spore fungus belonging to a saprophytic microbes, to grow by decomposition, feed nutrient consumption, also release quantity of heat, make the material temperature is high, the result is a metamorphic feed protein, utilization rate is reduced, cut down the content of amino acids, still can make change fat, vitamin, as a result, scientific formula design according to full price, it is bound to become is not full and "residual value, and feed in the process of production, transportation, storage, use by oxidation and bacterial infections, and to mould growth provides favorable conditions, lead to more mycotoxin produced. At this point, the feed and raw materials of nutrient concentration has been compromised.
Second, poor management cases, the low standard of poisoning.
Such as high temperature, poor ventilation, crowded, dung cleaning not in time, the immune response is too strong, nutritional imbalance, disease etc. Will cause resistance to mycotoxin decline of livestock and poultry. Because of the small molecular compound mycotoxin, the body does not produce antibodies to its, therefore, improper management of stress, can make even under standard of harmful toxins can also cause the body poisoning animals.
Three, strong corrosive of animal digestive tract mucosa.
Will form the young ducks oral ulcer, esophagitis, chickens and other animals intestinal mucous membrane shedding, necrosis, which affects the body for digestion, absorption of nutrients. For example, will cause the VE and thiamine malabsorption, leading to immune suppression and neurological symptoms, and can make the intestinal form of pigment absorbing barrier, cause bad beak and claws.
In addition to intestinal digestive organs is one of the important organs of the immune body, its function is to induce the body on the antigen of microbial class of congenital and acquired immune response, intestinal also absorb the mycotoxin, when mycotoxin severely damaged the integrity of the intestinal epithelial cells, immunoglobulin secretion reduces, and immunoglobulin in intestinal mucosa plays an important role in the immune response, toxicity of mycotoxin inhibit the synthesis of proteins, the intestinal immune system destruction will cause poultry with higher susceptibility to infectious diseases.
Fourth, the damage to the liver, cause liver cell necrosis, congestion late form "rubber liver.
Liver reserve function of glycogen, glycogen decreased, hypoglycemia, often drink glucose is invalid; Will interfere with the synthesis and transport of liver yolk precursor, and then falling rate and eggs with a small increase.
Five, the damage to the kidneys.
Can cause kidney swollen, gout, cartilage dysplasia, livestock and poultry leg higher incidence of disease.
Six, injury of blood vessel walls.
Increase blood pressure in livestock and poultry, aggravating heart burden and viscera tissue osmotic pressure rise, cause ascites syndrome.
Seven, the immune organ damage.
Except as described above for the destruction of the intestinal immune system, especially cause atrophy of the chicken thymus and bursa of fabricius, T lymphocytes and leukopenia, albumin and globulin content decreased, the antibody titer decreased, serum antibody concentration is reduced, cause immune suppression and make various virus disease happens.
Immune failure often considered quality of vaccine, vaccination process error, strong poison attack or other complicated factors, cause immune failure and mycotoxins, but often neglected, a lot of disease in the normal immune occurred after, so that the health of livestock and poultry should not have infectious pathogen will be conditioned pathogen infection caused by the mold toxin poisoning. Somebody thinks, after used the vaccine antibodies are any drops, probably related to the mycotoxin.
Eight, chicken feed intake of aflatoxin contamination, LiangSuo postpartum chickling susceptibility to disease increase immune function.
According to the measurement, the chicken in the Newcastle disease to spread the serum antibody titers after routine immunization significantly below the normal level of chicken. And invade the breeder eggs of mycotoxin would result in higher hatch chickens, ducks and other poultry stillbirth rates, offspring chicks muscular stomach congenital lesions, prompted the intestinal disease, early and growth disorder, this extremely easily with the poor chicken and intestinal solitary mixed infection.
Recessive poisoning in chronic after more and different clinical manifestations, more for specific disease secondary disease rather than the toxin poisoning, which makes many times with other disease diagnosis to treatment of the disease.
For example: some inhibition of mycotoxin production performance of laying hens, reflect not to come out in a short period of time, in the first place over time, body endotoxin accumulation increased, to the middle of the performance until late.
Had a case of laying hens, the poisoning after the onset of the early feeding by fine slow, where expect to reduce gradually, after the development for refusing foods and egg production is on the rise, peak to maintain 25 days began to decline.
According to the analysis, it is because this batch of brood chicken breeding is good, and is in the egg stage and reproductive function, and the negative balance of nutrition is not apparent until 25 days, the surface is very easy to mislead the diagnosis,
Like: 1 day age newborn chicks have obvious respiratory symptoms, only 10% had lung mould change, it is easily misdiagnosed as mycoplasma disease onset in chicks after 4 days of age, poor tend to growth, less food intake, weight is light, can be considered as weak ones, will cause the mold toxin poisoning 15 age small appear the cock's crow, cockscomb overdevelopment, mainly corn gibberellic ketene cause excessive, will be mistaken for early development.
Or: ochre and aspergillus toxin poisoning mainly kidney damage, characterized by diuresis function strengthen, at this point, the chickens polyuria dehydration, due to the spill, diuresis laying hens diarrhea cured, egg drop, broiler chickens grow slowly, anemia, forming disease rickets. Is a drop in digestive disorders, feeding livestock, thick coat, female abortion, estrus, essence of sire die there will be unknown high fever, such as low immunity.
These symptoms can easily interfere with clinical diagnosis. , therefore, in the aquaculture production practice and veterinary clinical diagnosis, to the harm of mold and mildew toxins have enough understanding, to join in the comprehensive analysis of the factors, to pay attention to and accumulate experience in this field, for suspected cases as far as possible with the aid of equipment means to improve the diagnosis rate, such as: tissue tabletting microscopy, disease vaccination culture, which in general laboratory can do; Biological identification of can also, such as: the suspicious material for animal ill test, have the corresponding condition of goose of cheeper duck method can be used, this is the world's legal generic methods.
Choose 1 day age goose of cheeper duck, through the tube feeding toxin, raised after 6 to 7 days, according to the autopsy to determine the degree of bile duct epithelial dysplasia, also desirable goose of cheeper duck liver tissue for histologic examination.
Suspicious feed and raw materials chemical analysis method can be used to determine standard comparison, also can use the samples in fluorescent colour and lustre is observed under uv lamp to intuitive judgment, but it needs enough experience.
Because there is no the antidote to mold and the mold toxin, conventional treatment to cooperate on, such as: using nystatin, clotrimazole and extra added in feed can promote liver detoxification function of nutrients, composite VB, methionine will help accelerate the metabolism of livestock and poultry, get rid of toxins, VA, VC, VE, selenium would ease mycotoxin toxicity to the cells of the body.
With enzyme preparation can reduce the absorption of toxins in the body, oxidase can also destroy the molecular structure of toxins, reducing toxin harmful toxic, and can obviously promote detoxification, detoxification of poisoning viscera.
General books introduce potassium iodide or copper sulfate solution water treatment of the disease, according to the laboratory testing, should have relatively high concentrations have bacteriostasis, usually 1:30 00 a laparoscope, usually connected to a copper sulfate water for three days, have different clinical application effect, needs further validation.
Insist on prevention is fundamental to lift the mold and the mold toxin harm. Feed store to dry and ventilated, storage period is shorter. Not forage moldy, timely replacement bedding, mould don't graph save trouble, add throughout the feeding amount at a time, in the high temperature and high humidity of the inner environment, cause mould easily. Corral to fully ventilated platoon is wet, drinking utensils supplies to wash clean, let the sun illuminate more than 4 hours, the brood chamber, incubator to disinfect with formaldehyde, peracetic acid, chicken group added in water sprinkling water operation to avoid anywhere, to control the inner temperature and humidity.
Feed mills and producers since the ingredients can be added in the new corn propionic acid, to kill the mold, but the mycotoxin propionate is without any damage, add some efficient mould adsorbent, decomposition agent can also play a role in prevention, especially the use of corn lees feed, more attention should be paid to add, because processing one ton of corn to produce about 300 jins of grains, these grains will be concentrated in the equal to three times the amount of mycotoxin.
And with dry corn and the new corn against the mixing ingredients, can dilute concentrations of mycotoxin, as long as no concentrations exceeding the standards and didn't have a lot of harm, and the crowd to the sensitive degree of mycotoxin varies inversely with age, the greater the day age of chicken, tolerance is stronger, the chicken of mycotoxin tolerance low and subsequent influence is bigger, can focus on this in feeding.
In feed mills in the grain production process, attention should be paid to crush around before feeding into the machine easily absorb moisture, heap pressure time is too long, storage and poor ventilation, drench, insolate easy cause mould contamination, after the powder into the machine to control a vapor pressure, moisture content, time, to avoid pipe condensate water make the powder into the paint, the machine grain temperature, moisture content is exorbitant, can also lead to yellow aspergillus growth, and regular cleaning of grain formed in the ascension or pipeline mould product material.
Anyhow, fungal and poisoning disease prevention and control of mycotoxin is a dynamic process of continuous only each link concerted action, to get good results.
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