HPLC analyzes have demonstrated that the major carotenoid presented in the muscles of shrimp is astaxanthin, as a free or ester-compound; corresponding to 75% of the total carotenoids in both CS and SS groups (data not shown). Nevertheless, it was verified that CG possess 2.82 mg of astaxanthin/kg of muscle shrimp, while SS presented 4.55 mg of astaxanthin/kg of shrimp. These results demonstrate that even considering small quantities of other carotenoids presented in the original chow furnished to the shrimp (control group—CS), those carotenoids were able to convert carotenoids traces into astaxanthin. On the other hand, it was clear chow supplemented with the H. pluvialis algae yielded shrimp with higher content of astaxanthin. Furthermore, such a high astaxanthin content was responsible for the increased in vitro antioxidant activity observed for the carotenoids extract of the SS group in comparison to the control group.
The results show the ability of shrimp total carotenoids in preventing lipid peroxidation in the serum and liver of rats. Fig. 1 shows the determination of the TBARS levels after the induction of lipid peroxidation, in the rat serum and liver, using CuCl2 (Fig. 1) and AAPH (Fig. 2) as the oxidant agents. Considering the data from serum (Fig. 1A), it is observed that the carotenoids of the SS group presented a protective and concentration-dependent effect against lipid peroxidation, which was statistically similar to that of the synthetic astaxanthin (P>0.05). However, the total carotenoids of the CS group was lower when compared with synthetic astaxanthin (P