(full paper is archived in the Miller Library)
Title: Fat metabolism and physiology in captive yellowfin tuna (Thunnus albacares)
Student Author(s): Imai, Denise
Faculty Advisor(s): Block, Barbara
Location: Final Papers Biology 175H
Date: June 1997
Abstract: At the Tuna Research and Conservation Center, in Monterey, California, captive yellowfin tuna (Thunnus albacares) demonstrated an increase in lipid accumulation and mortalities when fed a high calorie and high fat diet. To dertermine what influence a high fat diet has on tuna physiology, one tank (T2) holding 28 fish was designated for diet manipulation while oxygen consumption and stomach temperatures were used to measure changes in metabolism. No significant differences in metabolic rate were measured between diet treatments. The low fat diet (LFD; 1% fat content in kcal) was composed of squid and smelt while the high fat diet (HFD;8% fat content in kcal) only included sardines. Samples were sent away for bomb colorimetry analysis and based on these values, an equivalent total caloric level (28 kcal/kg/day) was maintained between diets. Individual respirometry trials were performed in a Closed-system respirometer. Three trials were run for each diet treatment and swimming velocity was measured for each run to calculate standard metabolic rate (LFD: 135.70 +/-42.79 mg O2/kg/hr; HFD: 147.54+/-8.89 mg O2/kg/hr;p=0.80). Whole tank metabolic rate was measured using T2 as an Open-system respirometer with help from the dissolved oxygen monitoring system (Program Logic Control) operated by Monterey Bay Aquarium. Stomach temperature was measured by minilog temperature probes and no significant difference between diets was measured (pre-feed: p-0.91; post-feed: p=0.80).