Individual tissue weight to total body weight relationships and total, polar, and nonpolar lipids in tissues of hatchery lake trout

Individual tissue or organ weight to total body weight relationships, total lipid, and major lipid subclasses were measured in 3- and 4-year-old hatch ery-reared Lake Superior isle Royale strain "lean" lake trout Salvelinus na maycush to obtain a more in-depth understanding of the major lipid compartm ents of lake trout for use in predicting the distribution and disposition o f xenobiotics in these fish. No significant (P > 0.05) differences between males and females were observed in individual tissue or organ weight to tot al body weight relationships. The weight of internal organs and tissues mad e up approximately 11% of body weight, while the remaining carcass accounte d for 85%. Muscle accounted for slightly more than half of the carcass weig ht. Dorsal and ventral muscle were approximately equal in proportions. Mean (+/-SD) calculated whole-body total lipid for the lake trout was 15.2% (+/ -2.2%). No significant (P > 0.05) differences between males and females wer e observed in total lipid content or in the major lipid subclasses (polar. nonpolar) for the individual tissues and organs of the lake trout except fo r gonads. The total lipids in lake trout blood, tissues, and organs, ranked from highest to lowest, were viscera (48%),liver (15%). kidney (14%), carc ass (12%), skin (10%), brain (8%), dorsal muscle (5%), gonads (4%), and blo od (1%). Total lipid content of ventral muscle (12%) was more than two time s that of the dorsal muscle (5%). Analysis of lipid subclasses showed lake trout tissues and organs had significantly higher (up to eight times higher for kidney) levels of nonpolar lipids than polar lipids.