Bile acids as endogenous molecules synthesized from cholesterol are regarded as pleiotropic mediators that regulate multiple physiological processes and mediate the utilization for different nutrients. By virtue of their amphipathic structure, bile acids are capable of solubilizing lipids by forming micelles, thus enhancing the digestion of lipids, cholesterol and lipid-soluble vitamins, promoting lipid utilization and protecting animal liver. Besides, bile acids could also function as hormones or signaling molecules, performing pleiotropic activities by activating nuclear hormone receptors. It has been clarified that bile acids could take part in the regulation of the antioxidant defense and immune response. The objective of this present study is to study the efficacy of bile acid supplementation in diets on shrimp growth performance, and hepatopancrease health.
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The study is assigned in CRD with four treatments and five replicates. Four diets with different levels of fish oil and bile acid (Shandong Longchang Animal Health Product Co.,Ltd, China) are exhibited in Table 1.
Shrimp of 1.5 gram/shrimp are randomly distribute to each cage of 2 × 1 × 1 m (totally 20 cages) installed in earth pond of 10-12 ppt saline water at 100 shrimp/cage then the density is 50 ind./m3. During the 8-week feeding trial, shrimps are fed experimental diet 5-10% BW, three times a day and sampling every 2 weeks for observed growth performance and adjusted feed given. Hemolymph is collected at the end of 8 weeks for determined immune response. The hepatopancrease health and lipid deposition are evaluate by wet mount technique under light microscope. The results in Figure 1 shows that growth performance of white shrimp fed different fish oil diets incorporated with bile acid have trended to improvement (p<0.1). Feed conversion ratio shows the significantly improvement (p<0.05). Shrimp fed T1, T3 and T4 demonstrate the trend of better specific growth rate (p<0.1) and significant better FCR (P<0.05) than T2. The hepatopancrease health and lipid deposition presents in Figure 2 shows the improvement in shrimp fed bile acid especially on lipid deposition of T3 and T4 compares to T2 and T1, respectively. Therefore, bile acid 0.03-0.045% could promote the shrimp growth performance including hepatopancrease health under nutritional stress of energy reduction and high antinutritional factors from plant protein.