Etiology, diagnosis, Prevention and treatment of Porcine Yellow Fat Disease

1. The concept of porcine yellow fatty disease.

Porcine yellow liposis is a pigmented disease characterized by yellow adipose tissue in pigs, which is called "yellow fat", and some are also called yellow liposis or nutritional panniculitis. Pork with yellowed subcutaneous fat after slaughtering pigs is called "yellow fat meat" caused by feed, and "jaundice meat" caused by disease.

2. Etiology of porcine yellow fat disease

There are two main causes of jaundice in pigs: one is pathological, which is called jaundice, and there are differences between substantive jaundice, obstructive jaundice and hemolytic jaundice. The etiology is caused by trypanosomiasis, burgomiasis or Leptospira invading the body, causing massive hemolysis in the body, poisoning and systemic infection, bile excretion disorders, so that a large amount of bilirubin is excreted into the blood and various tissues of the body are dyed yellow. Causing jaundiced flesh. This paper mainly discusses the reasons for the formation of yellow fat by feed factors.

2.1 the content of unsaturated fatty acids in feed is too high

If all or part of the feed is fish or its by-products (cod liver oil scraps, the by-products of flounder and salmon are the most dangerous), fish meal, silkworm pupa meal and oil dregs, oil grains, rice bran, corn, soybean cake, flax cake, fly feed and other high-fat, easily rancidity raw materials, in the case of more than 20% of the diet and the feed contains high unsaturated fatty acids or insufficient tocopherol. It greatly increases the consumption of vitamin E in the body, causing the relative lack of vitamin E in the body, coupled with the lack of other antioxidants, leading to the deposition of acid-resistant pigments in adipose tissue. And make the adipose tissue form a brown or yellow indefinite unsaturated complex body, promote the production of yellow fat.

2.2 Feed contains raw materials with high pigment content

Such as Ziyunying (grass seeds), turnips, carrots and pumpkins, these raw materials have high contents of carotene and lycopene, which cause yellow staining due to incomplete metabolism in the body. In addition, if the raw materials sold by the raw materials merchants themselves are dyed, such as dyed adulterated cottonseed meal, citric acid dregs, fake DDGS (substitutes for soybean meal, made from corn husks, urea and yellow dyes), etc., if pigs eat the feed made from these raw materials, the dye will be deposited on the fat and become yellow fat.

2.3 drugs causing porcine yellow fat disease were added to the feed.

For example, sulfonamides and some colored Chinese herbal medicines are slaughtered after being used for a long time or without a long enough withdrawal period, resulting in yellowing of pig carcass or whole body fat.

2.4 Feed mildew

When pigs are fed with Aspergillus flavus feed, such as corn, peanuts, etc., postmortem examination will find that the whole body fat is light yellow. The "variant" premix will cause damage to the pig body in the piglet stage, coupled with the raw material mildew will oxidize the oil, increase the temperature and prolong the feeding period and other factors make some pigs "win the bid" jaundice.

2.5 the formula or production process of feed additive is unreasonable

The formula with high copper can oxidize and rancidity the oil in the feed and lead to yellow fat. Almost all the feeds that produce yellow fat are using high copper! In fact, high copper itself does not lead to yellow fat, but lies in the catalytic oxidation of high copper itself. the use of copper is mainly related to antibiotic-like activity. when the addition of vitamin E is in the critical state, high copper leads to the acceleration of feed oxidation and increases the requirement of vitamin E, especially under hot and humid conditions. Under general conditions, the mixed retention time of 30 ℃ vitamin E and feed copper sulfate is about 3 days, and the loss is more than half, while under humid conditions, this loss is faster and more obvious, which is the main reason why the pelleted feed is more likely to lead to yellow fat.

If the feed production line is poorly ventilated (especially the corn crushing system), a large amount of heat and water vapor produced in the corn crushing process will condense on the surface of the crushed corn, resulting in the peroxidation of unsaturated fatty acids in corn, or the long interval between production and use of the mixture will cause the peroxidation of unsaturated fatty acids in the feed. In the season of high temperature and high humidity, the unsaturated fatty acids in the feed are more prone to rancidity, and the rancidity fat can form yellow fat; in addition, the deteriorated starch leads to bile leakage and the formation of yellow fat, which is actually the same as jaundice; high temperature and high humidity are encountered during conditioning and granulation, and with the participation of copper, this yellow fat changes more rapidly.

3. Pathogenesis.

The pathological changes of porcine yellow liposis are mainly characterized by obvious inflammation of adipose tissue and "wax-like" pigment deposited in adipocytes. Unsaturated fatty acids in adipose tissue are easy to be oxidized to wax-like materials. it is reported that brown or yellow droplets or amorphous bodies of 2 ~ 40 μ m are insoluble in fat solvents and show deep complex red in acid-fast dyeing. It is this anti-acid pigment that makes adipose tissue yellowing. Vitamin E, an antioxidant, can only prevent or delay the self-oxidation of unsaturated fatty acids, prompting fat cells to convert unsaturated fatty acids into stored fats. when excessive unsaturated fatty acids and vitamin E deficiency exist at the same time, the oxidation of unsaturated fatty acids is enhanced, the deposition of wax-like substance in adipose tissue is accelerated, and the inflammatory reaction of adipose tissue leads to the yellowing of fat to form yellow fat.

Jaundice is due to the occurrence of a large number of hemolytic diseases, some poisoning and infectious diseases, resulting in bile excretion disorders, resulting in a large amount of bilirubin into human blood and tissue fluid, dyeing all tissues of the body yellow.

Previous page [1] [2] next page