Dietary effects of lipid source, lipid level and temperature on growth of glass eel ( Anguilla anguilla)

Abstract

The influence of the oil level (10 and 20% in the diet), from different sources (poultry and soyabean), in a purified diet on the growth and body composition of glass eels ( Anguilla anguilla), maintained at three different temperatures, 23, 25 and 27°C, was examined. Glass eels maintained at temperatures of 25 or 27°C had a significantly ( P<0.05, t-test) higher body weight than those maintained at a temperature of 23°C. The average weight increase of glass eels fed on poultry oil (5 and 10% oil in the diet) and maintained at 25 and 27°C was significantly higher than that of glass eels fed on soyabean oil at the same percentages and maintained at the same temperatures. There was a significantly higher lipid content in the glass eels maintained at temperatures of 25 and 27°C and fed poultry oil than in the glass eels fed soyabean oil. The percentage of 18:1 fatty acid was greater in the body lipids of glass eels fed poultry oil than in those fed soyabean oil, and also greater in the body lipids of glass eels fed a high percentage of poultry oil (10%) compared with a low percentage (5%). The percentage of 16:0 and 16:1 fatty acids was similar to that of 18:1, i.e., higher in the body lipids of the glass eels fed poultry oil than in those fed soyabean oil. The percentage of 18:2 fatty acid was higher in the body lipids of the glass eels fed soyabean oil than in those fed poultry oil.