Improving the fat utilisation rate

As the main component of bile, bile acids play a vital role in the process of fat digestion and absorption. During the fat emulsification stage, bile acids molecules have both hydro- philic hydroxyl groups and carboxyl groups, and hydropho- bic alkyl groups. They have a very strong surface activity that promotes fat emulsification, forming fat particles that can suspend in water and expand the contact area between fat and lipase, which helps to fully prepare for lipase digestion of fat. During the fat digestion stage, bile acids can activate lipase. The precursor of pancreatic lipase is prolipase, which must be converted to an active lipase in the small intestine with the participation of bile acids. After entering the small intestine, pancreatic lipase combines with bile acids to form a compound. The lid structure of pancreatic lipase is opened, the catalytic group is exposed, and the spatial structure changes to form an active lipase. In the study of the effect of bile acids on the growth performance of broilers, Wenqing Lai et al. found that an addition of 60 ppm bile acids to the diet could significantly improve the activity of lipoprotein lipase (LPL) and lipase (LPS) in the duodenum, jejunum and ileum of broilers. During the fat absorption stage, medium and short-chain fatty acids can enter the blood circulation directly through the portal vein and be used by the body. Long-chain fatty acids must combine with bile acids to form a compound in order to complete the absorption process. According to Table 1, the lipoprotein lipase activity in the duodenum increased by 53.46%, and the lipase activity in- creased by 57.60%; the lipoprotein lipase activity in the jeju- num increased by 15.15%, and the lipase activity increased by 13.00%.