
普霉克© |
Mycotoxins are secondary metabolites produced by fungi when they grow on agricultural products before or after harvest, during transportation or storage. The molds most commonly involved belong to the genera Aspergillus, Penicillium and Fusarium.
Mycotoxins pose a severe threat to humans and as well as causing huge economic losses in the feed and food industries. These toxic substances are known to be either carcinogenic (e.g. aflatoxin B1,ochratoxin A, fumonisin B1), oestrogenic (zearalenone), neurotoxic (fumonisin B1), nephrotoxic (ochratoxin), toxic to epidermis (trichothecenes) or immuno-suppressive (aflatoxin B1, ochratoxin A and T-2 toxin).
The best known consequences of mycotoxins are their clinical (diseases) and subclinical (productivity losses) effects on farm animals. The reduction of the value of raw materials and complete feeds is a lesser known but very important repercussion.
Broilers are less sentitive to mycotoxins due to their short life cycle. Digestive lesions and failure of AGP-free programs are the most common consequences of mycotoxins.
In layers and breeders, mycotoxins reduce productivity by 0.08 eggs/hen/week, on average, and increase the occurrence of eggs with defects (thin-shelled and cracked eggs, pale yolks, etc)
Ducks, geese and turkeys are more sentitive to mycotoxins than chickens. The most common signs are low live weight, increased mortality and oral lesions.
In rabbits, mycotoxins disrupt the reproductive cycle, reduce feed intake, make the animals prone to digestive infections and increase mortality.
Pigs are extremely sensitive to mycotoxins. Digestive, respiratory and immune alterations, disruptions of the resproductive cycle, productivity losses and failure of AGP-free programs are the most common consequences of mycotoxicosis.
Ruminants are less sensitive to mycotoxins because microorganisms present in the rumen are able to totally or partially detoxify certain toxins.
The risk by mycotoxin contamination is often overlooked by the aquaculture industry, but shrimps and fish are quite sensitive to mycotoxins and the occurrence of contaminated feeds is high.
The reduction of the value and utilization of feedstuffs is a lesser known but very important repercussion, and key for the economic success of the farm.
普霉克© |
家禽饲料在生产和运输过程中的所有阶段,从谷物的种植到家禽养殖场的储存,都容易滋生真菌。尽管制粒后真菌数量会明显减少,但是全价料在运输和储存过程中可能会受到能产生霉菌毒素的真菌的污染。
霉菌毒素是由曲霉菌,青霉菌和镰刀菌等霉菌毒素产生的有毒次级代谢产物。其对动物最主要的也是最著名的影响是造成临床(疾病)和亚临床(生产力损失)症状,霉菌毒素还造成谷物和饲料营养价值降低,人们对此知之甚少,而这其实也是非常重要的危害。据估计,霉菌毒素每年给美国农民造成将近十亿美元的损失。(Schmale等, 2014)。
春天来了,很快北半球的天气将变得温暖而潮湿。春夏季节,农民对霉菌及其最知名的代谢产物—霉菌毒素更关注。但是,正如我们后面将讲到的,霉菌的生长不仅仅与温暖潮湿的气候有关,霉菌毒素也不是霉菌产生的唯一危害。