The regular shell colour of farmed Litopenaeus vannamei is off -white to greenish-white but instances of L. vannamei with brown-shell colour do occur in farmed shrimp. Physically, except for colour, the white-shelled vannamei and brown-shelled vannamei appear similar.
A study was conducted to determine if there were differences in the white- and brown-shelled shrimp vis-à-vis shell colour, meat colour, meat composition and meat texture. White-shelled vannamei was determined to be better in terms of meat composition and texture profile but brown-shelled vannamei yielded a more brightly red-coloured cooked product.
Reference (open):
B. Madhusudana Rao, P. Viji and Jesmi Debbarma. Shell colour variation in farmed Litopenaeus vannamei: Comparison of white shell (regular) and brown shell (unusual) L. vannamei. Aquaculture, Volume XXI No. 1, January-March 2017
http://www.enaca.org/modules/library/publication.php?publication_id=1193
Source: NACA
