Effect on Fatty Liver in Laying Hens

Fatty liver syndrome (FLS), also known as fatty liver hemorrhagic syndrome, is a common nutritional and metabolic disease in laying hens. It mainly causes excessive accumulation of fat in liver cells, thereby affecting the normal function of the liver, and in severe cases, even leading to liver cell rupture, intrahepatic hemorrhage, and death.?

Chicken flocks suffering from fatty liver disease are unlikely to experience peak egg production, and the egg production rate generally gradually decreases when it rises to around 85%. The incidence rate of cage laying hens is often about 5%, accounting for 8%~30% of all dead hens, which brings significant economic losses to the laying hens industry.

Fatty liver occurs when nutrients are deficient or insufficient, such as choline (or Choline chloride, Betaine), methionine, vitamins, and other cofactors involved in the synthesis of lipoproteins or lipoproteins carrying fat out of the liver. The excessive glucosinolate and Aspergillus flavus in the feed will reduce the ability of the liver to synthesize lipoproteins and make fat deposit in the liver.

In addition, during the peak egg production period, estrogen activity promotes the synthesis and deposition of fat in the liver, while significantly increasing the levels of blood lipids and cholesterol in the blood, leading to an increased risk of developing fatty liver.

In order to prevent fatty liver from causing greater economic losses to laying hens, prevention is the main method. In addition to drug treatment, the addition of Bile acid has a definite effect.

Hepatocytes are closely related to the biosynthesis, secretion, uptake, processing and transformation of Bile acid. When hepatocytes are injured or bile ducts are blocked, Bile acid metabolism will be blocked. When liver parenchymal cells are diseased, the synthesis function of Bile acid is damaged, and the ratio of primary Bile acid (CA/CDCA) becomes smaller or even inverted, the amount of CA is significantly reduced, and the synthesis of CDCA is compensated to increase.

After extracting brown adipocytes from experimental rats, researchers found that Bile acid can improve the activity of Thyroid hormones, while the activity of Thyroid hormones accelerates the basic metabolism, and promotes the "burning" of excess fat. At the same time, the effect of Bile acid on improving the activity of Thyroid hormones is limited to Muscle cell, which has little risk of side effects. The mechanism of Bile acid promoting fat "burning" needs to be further studied and applied in layer production.

Most of the fat in the feed is broken down into fatty acids and glycerol through the action of lipase in the chicken body. The complex formed by fatty acids and bile salts can be dissolved in water and absorbed by the chicken body. A part of fat is also highly emulsified into very fine fat particles under the action of Bile acid salts, which can be directly absorbed.

In addition, the reabsorption of Bile acid was severely reduced after ilectomy for test layers, and Bile acid was lost too much, leading to Malabsorption of fat digestion. This is because the small intestine plays an important role in maintaining the Enterohepatic circulation of Bile acid.