Synthetic astaxanthin has better effects than natural astaxanthins on growth performance, body color and n-3 PUFA deposition in black tiger prawn (Penaeus monodon)

Astaxanthin is an efficient nutrition strategy to relieve oxidative stress and enhance crustacean body color. Because of technological and economic benefits, synthetic astaxanthin is favored by the aquatic feed industry. However, whether synthetic astaxanthin can achieve the effects of natural astaxanthin needs further investigation. Here, we evaluated the effects of synthetic astaxanthin and natural astaxanthin (dietary supplementation with Haematococcus pluvialis and Phaffia rhodozyma) on the growth performance, body color, fatty acid composition and antioxidant capacity of black tiger prawn (Penaeus monodon). Compared with the control group (no astaxanthin supplementation), only synthetic astaxanthin significantly increased the weight gain rate (WG) and specific growth rate (SGR), together with the elevation of feed efficiency ratio (FER). All three types of astaxanthin enhanced body color by increasing astaxanthin deposition. The highest value of (a*) in the carapace and muscle occurred in the synthetic astaxanthin group. Synthetic astaxanthin significantly increased the n-3 polyunsaturated fatty acid (n-3 PUFA) contents in muscle. As expected, different sources of astaxanthin inhibited glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) activities in the hemolymph and decreased the contents of reduced glutathione (GSH) and malondialdehyde (MDA) in the hepatopancreas. Correspondingly, the structure of hepatopancreas was enhanced by astaxanthin. In addition, three types of astaxanthin almost indistinguishably enhanced the ability of shrimps to resist stress caused by transportation simulation. In conclusion, these results indicate that dietary synthetic astaxanthin has a better effect than natural astaxanthin on growth promotion, body color enhancement and n-3 PUFA deposition in muscle of black tiger prawn. Hence, synthetic astaxanthin is a suitable feed additive to promote the healthy and sustainable development of the shrimp industry.