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Bile acids: a performance boost for shrimp


Bile is crucial for lipid absorption in the animal’s gut. However, Vannamei shrimp are unable to synthesize bile salts themselves. Supplementation of bile acids is therefore needed to keep health and performance at desired levels.


BY DR ZHANG WEI, LACHANCE GROUP T 1 30


he mechanism and application effects of bile acids on freshwater and marine fish have been widely recognised by the aquatic industry. Bile acids are mainly produced in liver cells with cholesterol as


a precursor. Under the action of 7-α hydroxylase, a steroid substance is produced, which is an important composition of the bile that can promote the digestion and absorption of fat, metabolism of sugar, protect the liver and eliminate toxins. The cholesterol in vertebrates e.g. fish, is converted into bile salts in the liver and discharged into the digestive tract with bile to participate in the digestion and absorption of lipids. However, crustaceans such as vannamei shrimp are unable to synthesize bile salts. Therefore, bile acids are an essential nutrient in compound feed for these species. There are three main reasons why it is recommended to add bile acids to the diet of Penaeus vannamei, spurred by changes in the feed ingredients used and pathogen pressure.


Shrimp diets are changing Replacing fish meal with plant-based protein sources has become essential in the development of the shrimp feed industry. Plant-based protein contains


anti-nutritional factors, and insufficient cholesterol necessary for the growth of crustaceans such as shrimp. However, add- ing supplemental cholesterol to the feed will greatly increase costs. In order to improve the absorption and utilisation of cholesterol in feed and make up for the lack of cholesterol, the precursor substance of moulting hormone, it is necessary to add bile acids to shrimp feed. The role of bile acids: To promote the digestion and ab- sorption of oil and cholesterol, increase the storage of nutri- ents in the hepatopancreas, and provide fundamental materi- als for moulting and immunity. Bile acids combine with the


▶ ALL ABOUT FEED | Volume 29, No. 9, 2021


lipase in the digestive tract, expose its catalytic group and change its spatial structure, improve the activity of lipase, so as to promote the digestion and absorption of oil and choles- terol. In addition, bile acids can improve the utilisation of lipids in feed, so that more lipid droplets will be stored in the hepatopancreas, which can meet the energy requirements of the shrimp during the moulting process, and get prepared for subsequent growth, moulting and immunity.


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Economic damage of diseases Early mortality syndrome (EMS) and white feces syndrome (WFS) caused a severe strike on the van- namei industry of the whole of South America.


Studies show that both EMS and WFS are hepatopancreas dis- eases caused by Vibrio. In order to inhibit harmful bacteria, bile acids must be added. The role of bile acids: Inhibit harmful bacteria flora and protect health. Recent studies show that cholic acid and de- oxycholic acid have a significant inhibition effect on Gram positive bacteria e.g. Staphylococcus aureus and Gram nega- tive bacteria e.g. Escherichia coli. Bile acids can maintain the integrity of the intestinal mucosa, prevent harmful bacteria, and reduce the pH of the intestine environment. Bile acids have a significant antibacterial effect, maintain the balance of intestinal bacterial flora, and protect health.


ANFs and mycotoxin risk Due to the existence of anti-nutritional factors (ANFs) in plant protein, the nutrients in shrimp feed can’t be fully digested, absorbed and utilised. In ad-


dition, raw materials such as peanut meal are very likely to carry mycotoxins, which will cause severe damage to the hepatopancreas and slow down the growth of shrimps. The role of bile acids: Bile acids play an important role in intestinal immunity by combining or decomposing endotox- ins in the hepatopancreas and intestines, reducing the ab- sorption of endotoxins by the intestines, and preventing the intestine and hepatopancreas from secondary damage due to endotoxins, ANFs and mycotoxins.


Proven effects of bile acids A large number of studies have been done that confirm that bile acids improve the growth performance of shrimps.


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