White shrimp (Penaeus vannamei) is the most economically significant marine shrimp species in Thailand in terms of production. Numerous feed additives are available to promote growth and immune response in aquatic animals, and one such additive is bile acid. Bile acid is a type of organic compound that is produced by the liver and secreted into the intestine. However, bile acid can play a role as feed additive to make many benefits. The valuable role of bile acid is improving growth rates and feed utilization by increasing the digestibility of dietary fats and proteins. Bile acids are secreted into the intestine to aid in the digestion and absorption of fats, and it can also promote the activity of certain digestive enzymes, such as lipase. This can support the shrimp to break down and absorb nutrients more efficiently, leading to improved growth rates and feed conversion ratios. In addition, bile acids enhance the activity of certain immune cells, like hemocytes and lymphocytes, and increase the production of immune molecules, lysozyme and phenol oxidase. The objective of this present study is to study the effects of bile acid supplementation in diets on shrimp growth performance and immune response.
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The study is assigned in CRD with three treatments and five replicates. Three diets supplemental with different levels of bile acid are prepared, a) Control without bile acid addition, b) T1 diet of bile acid at 0.015% and c) T2 diet of bile acid at 0.03%. White shrimp with initial mean weight of 1.531 ± 0.012 gram/shrimp are randomly 100 shrimp distributed to each cage of 2 × 1 × 1 m per cage (totally 15 cages) in salinity 10-12 ppt pond then the density is 50 ind./m3. During the 8-week feeding trial, the shrimps are fed 5-10% of their body weight three times a day. Shrimp are weighed every 2 weeks and culture for 8 weeks then collected hemolymph sample mixed with tri-sodium citrate for study immune response. The results in Figure 1 shows that white shrimp fed diets of bile acid at 0.015%/kg and 0.03%/kg are not significant different (P >0.05) on final weight, weight gain, and FCR. The results of immune response show that under normal condition superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and lysozyme activity, are not significantly differences (P >0.05). However, in Figure 2, phenol oxidase (PO) is significantly differences (P = 0.003) and hemolymph protein (TP) exhibit the trend to increase (P = 0.06) in shrimp fed diets of T1 and T2. In conclusion, bile acid 0.015% to 0.03% in shrimp diet is recommended for promote immunity of shrimp, feed utilization and growth performance.