The effect of dietary phosphatidylcholine and its constituent fatty acids on microdiet ingestion and fatty acid absorption rate in gilthead sea bream, Sparus auratus, larvae

This study tested the effect of the level of dietary phosphatidylcholine (PC) and its constituent medium-chain fatty acids on microdiet ingestion (μg diet larva^-1 h^-1) and the absorption rate of the free fatty acid [¹⁴C]16:0 (pmole larva^-1 h^-1) in 15, 20, 21, 25, 26, 30 and 31-day-old gilthead sea bream, Sparus auratus L., larvae. Fish were fed four microdiets (A, B, C and D): microdiet A contained no phospholipid (PL), while microdiet B included 10 g kg^-1 Artemia nauplii PL (3.7 g kg^-1 PC). Microdiets C and D contained 10 g kg^-1 purified saturated PC dimyristoyl (C_14:0) and polyunsaturated PC dilinoleoyl (C_{18:2[cis]-9,12}), respectively. Larvae from one or both of the PC microdiets demonstrated significantly higher (P < 0.05) ingestion rates (μg diet larva^-1 h^-1) than the non-PL microdiet control in 15, 21, 22, 25 and 26-day-old larvae and the Artemia PL microdiet in 15, 22 and 26-day-old larvae. However, microdiet ingestion and fatty acid absorption rate appeared to be independent of the associated medium carbon chain saturated or polyunsaturated fatty acid moiety of the PC diets. Apparent absorption, as measured by the retention of radio-labelled [¹⁴C]16:0 following 8 h of non-labelled microdiet feeding, was possibly related to feeding.