Carotenoids from Shrimp Waste as a Natural Dye for the Feather Colouring of Canary Birds Serinus canaria domestica

Abstract

Carotenoids are naturally occurring pigments in plants, algae, fungi, insects, and crustaceans. Krill and prawns contain high levels of some value-added nutrients for the aquaculture industry, such as astaxanthin which is used as a colouring agent. In birds with ornamental plumage, such as canaries, the carotenoid-pigmented plumage and red hues are exclusively due to the diet. In this regard, our aim was to study the possibilities of using shrimp waste for feather colouring in canary Serinus canaria domestica. Shrimp Pandalus borealis dried waste was included in the feed of six female red lipochrome mosaic canaries Serinus canaria domestica for three months during their third molt. The basic diet consisted of a seed mixture (canary seed, sunflower seed without shell, linseed, and rapeseed), rearing food (Quiko®Bianco), and conditioning food (Quiko®Rusk) with the supplementation of an oil suspension of dried shrimp waste (3%). The ad libitum-fed birds had additional free access to pasta (Legazin® Procria White Morbida). To evaluate the effect of shrimp waste on feather colouring, covert feathers were taken from the tail in the region of the uropygial gland. Diffuse reflectance spectroscopy of the most intensely coloured parts of the feathers was measured by a spectrophotometer. The chromaticity coordinates in a CIE xyY colour space were calculated from the measured spectroscopy. The results of the experiment showed that shrimp waste increased chromaticity and had no negative effect on the canaries. On this basis, the authors assumed that dried shrimp waste could be an alternative to synthetic dyes.