Dietary deficiency of docosahexaenoic acid impairs vision at low light intensities in juvenile herring (Clupea harengus L.)

Abstract

In the retina of herring (Clupea harengus L.), rods are recruited from about 8 wk after hatching, and from this time there is a linear relationship between the number of rods in the photoreceptor cell population and the content of di22:6n-3 molecular species of phospholipids. Juvenile herring were reared from four weeks' post-hatching for 15 wk on either Artemia nauplii deficient in 22:6n-3 or on enriched Artemia nauplii containing 4.3% 22:6n-3. The visual performance of the fish was then determined at three light intensities (0.01, 0.1, and 1.0 lux) by observing their frequency of striking at live Artemia nauplii using infrared video recording. Herring reared on the diet containing no 22:6n-3 were less active predators, especially at the lowest light intensity where very few strikes were observed. The eyes of these fish contained greatly reduced levels of di22:6n-3 molecular species of total phospholipid, 2.1% vs. 12.0% in fish supplemented with 22:6n-3. The contribution of saturated and monounsaturated fatty acids in the molecular species of phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylcholine (PC) was virtually unchanged, while 20:5n-3 and 22:5n-3 largely replaced 22:6n-3. There was an almost complete disappearance of di22:6n-3 PC, while the amounts of di22:6n-3 PE and PS fell by 18.1 and 20.6% to 2.7 and 7.6%, respectively. The dipolyunsaturated molecular species di20:5n-3, 20:5n-3/22:5n-3, and di22:5n-3 made up a substantial part of the deficit. We conclude that a dietary deficiency of 22:6n-3 during the period early in rod development impairs visual performance such that the fish can no longer feed at low light intensities.

Physiological roles of fatty acyl desaturases and elongases in marine fish: Characterisation of cDNAs of fatty acyl Δ6 desaturase and elovl5 elongase of cobia (Rachycentron canadum)

“…Dietary deficiency of DHA resulted in larval Atlantic herring having an impaired ability to capture prey at natural light intensities (Bell et al, 1995), delayed response to visual stimuli in larval gilthead sea bream (Benitez-Santana et al, 2007), and impaired schooling behaviour in yellowtail (Masuda et al, 1998;Ishizaki et al, 2001) and Pacific threadfin (Polydactylus sexfilis) ). Previously, we have shown that 10-fold more DHA was produced from EPA than from 18:3n-3 in primary cultures of brain cells from turbot (Tocher et al, 1992).…”

Criteria for Safe Use of Plant Ingredients in Diets for Aquacultured Fish

“…Indications of impaired vision and neural development has been reported in larval herring ( Navarro et al 1993;Bell et al 1995;) and sea bass ( Bell et al 1996b;Navarro et al 1997) while good pigmentation in Japanese flounder required dietary supplements of 22:6n-3 (Estevez and Kanazawa 1996;Estevez et al 1997). The requirement of 20:4n-6 is probably much lower than for n-3 HUFA.…”

Tuna Nutrition and Feeds: Current Status and Future Perspectives

“…As described above, tuna species have generally higher levels of DHA and DHA:EPA ratios than in most other fish species and so it will be important to determine if this is reflected in a higher DHA requirement, particularly during larval development when there is considerable demand for lc-PUFA for neural tissue development (Sargent et al, 2002;Tocher, 2003;Mourente, 2003). The importance of DHA for the proper development of neural tissues has been demonstrated in larval Atlantic herring (Mourente and Tocher, 1992a;Bell et al, 1995;Mourente, 2003), European sea bass (Dicentrarchus labrax) (Navarro et al, 1997), gilthead sea bream (Mourente and Tocher, 1993;Mourente, 2003), and turbot (Psetta maximus) (Mourente et al, 1991;Mourente and Tocher 1992b;Mourente, 2003). Dietary deficiency of DHA resulted in larval herring having an impaired ability to capture prey at natural light intensities , delayed response to visual stimuli in larval sea bream (Benitez-Santana et al, 2007), and impaired schooling behaviour in yellowtail (Masuda et al, 1998;Ishizaki et al, 2001) and Pacific threadfin (Polydactylus sexfilis) .…”