Effect Of Sodium Taurocholate As Feed-additive On Pigmentation And Use Of Astaxanthin In Blood Parrot (Cichlasoma Synspilum♀×Cichlasoma Citrinellum♂)

Astaxanthin is a kind of physiologically important carotenoids involved in feedpigmentation, the enhancement of immunity, and the acceleration of growth andbreeding, and it is safe for humans. During recent years, astaxanthin has been widelyused in the foodstuff and forage industries as a dietary supplement for developingprospects. Aquatic animals cannot synthesize astaxanthin and therefore depend entirelyon dietary supplements to achieve their natural pigmentation. However, the differingabsorption efficiencies of astaxanthin in a variety of fish have produced dissimilareffects due to the relatively low digestibility of this carotenoid. Bile salts can facilitatethe emulsification of fat and fat-soluble compounds into lipid micelles within the smallintestine and can increase the area of operation of pancreatic lipase. Absorbed by thesmall intestine in free form and combined with lipoprotein transport after entering theblood, carotenoids in foods are hydrolyzed and digested after extraction in the digestivetract. Bile salts can increase the opportunity for carotenoid absorption in isolated cells.Sodium taurocholate is a type of bile salt and can serve to promote fat digestion andabsorption. Its action increases the opportunity for carotenoid absorption by loweringthe surface tension of fat and by emulsifying fat to produce many microdrops. Theobjectives of the present study are to examine the effects of different proportions ofsodium taurocholate as feed additives on the pigmenting efficacy of astaxanthin inblood parrot (C. synspilum♀×C. citrinellum♂) and to test whether sodiumtaurocholate can enhance astaxanthin pigmentation in blood parrot. The results showed:1. Blood parrot were fed for45days, when the feed have different proportions ofsodium taurocholate and the concentration of astaxanthin in the feed was400mg/kg, thetotal carotenoids in the skin and caudal fin of blood parrot were higher than controlgroup after15days.2. Blood parrot were fed for45days, when the concentration of astaxanthin in thefeed was400mg/kg and the concentration of sodium taurocholate was1200mg/kg, the total carotenoids in the skin and caudal fin of blood parrot were highest (P<0.05); nosignificant changes in total carotenoid content in muscle (P>0.05). The total carotenoidcontent was not always increased with increasing content of sodium taurocholate.3. Blood parrot were fed for60days, when the concentration of astaxanthin in thefeed was400mg/kg and the concentration of sodium taurocholate were1400and1600mg/kg, the total carotenoids in the skin and caudal fin of blood parrot were highest(P<0.05); Difference between the two groups was not significant (P>0.05).4. This study investigated the effect of sodium taurocholate supplied as a feedadditive on the pigmentation and absorption of astaxanthin in blood parrot. The resultsof the study showed that the carotenoid content was higher in the skin and the caudal finof the fish fed a diet supplemented with both astaxanthin and a certain amount ofsodium taurocholate. The study found that adding a certain amount of sodiumtaurocholate to the astaxanthin feed can increase the utiliza-213tion of astaxanthin andimprove the coloring effects of the carotenoid in blood parrot.