Lipid and fatty acid utilization in adult Penaeus monodon fed diets supplemented with various oils

Abstract

The absorption of certain lipids from ten types of oils supplemented into test diets was investigated with adult Penaeus monodon. Oils used were crude sardine, squid, cod liver, fish, tuna, soya and palm oils as well as refined squid, epa and corn oils. Chromic oxide was used as the inert marker for the assessment of apparent digestibility of individual fatty acids. Major proportions of free fatty acids in faeces indicated total and partial hydrolysis of dietary triacylglycerols for the different oil types. The apparent digestibility of individual fatty acids ranged from 63 to 100% and was shown to be dependent on the oil source. Digestibilities of saturated fatty acids decreased with increasing chain length ranging from 95% for 14:0 to 66% for 18:0, while the digestibility of monoenes increased with increasing chain length. Linolenic and linoleic acids were equally well digested, particularly from diets with soya and corn oils. With the exception of fish oil, polyunsaturated fatty acids were selectively well digested. Generally, the varying utilization of diets with crude or refined animal and plant oils suggests that the nutritive value of oils as dietary lipids in related to the content of free fatty acids and the composition of saturated fatty acids and long-chain unsaturated fatty acids. Possible effects of component fatty acids on the digestibility of individual fatty acids are discussed.