What causes the red/pink coloration in shrimp and does it have nutritional value?

Astaxanthin is the primary color pigment in many shrimp, and it helps provide their tissue with its red and orange shades. While many reddish-orange foods get their color from other carotenoids (or from flavonoids), shrimp are especially ...

from The World's Healthiest Foods http://ift.tt/2431yHy