Effect of dietary lipid and astaxanthin level on pigmentation of arctic charr (Salvelinus alpinus)

• Main Author: Lin, Shujun
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1997
• Subjects: Arctic; Arctic charr; Salvelinus alpinus
• Online Access: https://research.library.mun.ca/760/; https://research.library.mun.ca/760/1/Lin_Shujun.pdf; https://research.library.mun.ca/760/3/Lin_Shujun.pdf

A 3 x 3 factorial design was used to study the effects of dietary lipid and astaxanthin levels on the pigmentation of Arctic charr (Salvelinus alpinus). Different groups of charr with mean initial weight of 70.16 ± 2.18 g were fed with diets containing 10, 18 or 26 % dietary lipid together with 40, 60 or 80 ppm synthetic astaxanthin for 24 weeks. The proximate composition of flesh, total carotenoid concentration in flesh and belly skin, and the Hunter colour values of filets, homogenized flesh and belly skin were determined at 4-week intervals. The apparent digestibility coefficient of carotenoid and specific growth rate (SGR) of the experimental fish at different dietary lipid and carotenoid levels were also investigated. Results indicated that: -- (1). The moisture content of flesh was inversely related to the level of dietary lipid, while there was a significant direct relationship between the content of flesh and dietary lipid. The protein and mineral content of flesh were not significantly influenced by the level of dietary lipid. -- (2). The total carotenoid concentration in flesh and belly skin of charr increased with time. The concentration of carotenoids in the flesh generally reached or exceeded 4 mg/kg wet tissue on week-16, 20 and 24 for the fish receiving 26, 18 and 10 % dietary lipid, respectively. This amount is considered as being sufficient for providing a satisfactory colour impression. The carotenoid concentration in the flesh and belly skin of fish was directly correlated with both dietary lipid and carotenoid levels. There was a significant interaction between dietary lipid and carotenoid levels on the total carotenoid concentration in flesh and belly skin of charr. A high correlation also existed between the carotenoid concentration and total lipid content in flesh. -- (3). The intensity of redness (Hunter a) and yellowness (Hunter b) of filet, homogenized flesh, and belly skin for all treatments increased with time on pigmented diets while their lightness (Hunter L) decreased. The Hunter L ...