The effect of feeding regular or low α-linolenic acid linseed on the fatty acid composition of egg yolks

Abstract

Ninety Isa Brown laying hens aged 28 weeks, kept in individual cages, were randomly divided into 6 groups of 15 birds each. Six isoproteinous diets differing in crude fat content and fatty acid (FA) composition were prepared. The source of added fat was linseeds (50 g/kg diet), regular cultivars (Omega and Opal) with a high content of α-linolenic acid (HA), or a modified cultivar (Linola) with low α-linolenic acid-and high linoleic acid (LA) contents, soyabean oil, or LA linseed oil (20 g/kg diet). The control diet, with no fat supplement, contained 19 g, while the experimental diets, 38 g of crude fat per kg. The diets were fed for a 12-week and eggs were collected for chemical analysis at weekly intervals. The dietary fat level had no effect on the fat level in egg yolks. Eggs from hens fed diets with HA linseeds contained 3 times more α-linolenic acid, 2.5 times more EPA (C 20:5n-3 ) and DHA (C 22:6n-3 ) and 27% less arachidonic acid (C 20:4n-6 ) than control eggs (P<0.01). Those from hens fed with LA linseed, LA oil or soyabean oil, had similar levels of linoleic acid, EPA and DHA as control eggs and 14% more arachidonic acid. The ratio of n-6/n-3 PUFA was 3:1 in eggs from hens provided with HA linseed, while in the other groups it ranged from 9:1 to 14:1. In contrast to regular linseed, the use of linseed low in α-linolenic acid and rich in linoleic acid in hen diets is not beneficial for the functional value of eggs.

The effects of various dietary vegetable oil sources on villi morphology and liver aldehydes in young layers

“…Grobas et al (2001) showed that laying hens fed a diet containing 5% or 10% linseed oil during 12 weeks trial period produced eggs with the same yolk weights, egg weight and egg mass as control birds. The same results were reported by Beynen (2004) and Sosin et al (2006) on the yolk weight, but not the egg weight. They revealed that egg weight decreased significantly (P <0.05) by feeding linseed to the hens.…”

The effect of replacing soya bean oil with glycerol in diets on performance, egg quality and egg fatty acid composition in laying hens

“…The fatty acid profile of eggs is highly dependent on the diet of laying hens (Yannakopoulos et al, 2005;Sosin et al, 2006). The present study demonstrates that MUFA tended to increase with increasing levels of dietary glycerol, but this increase was not significant.…”

Effect of feeding whole linseed as a source of polyunsaturated fatty acids on performance and egg characteristics of laying hens kept at high ambient temperature

“…These results are consistent with the findings of Scheideler et al (1998), Novak & Scheideler (2001), and Bean & Leeson (2003), who reported no change in these egg characteristics in layers fed diets containing linseed. On the other hand, Baynen (2004), and Sosin et al (2006) reported that feeding layers with linseed reduced (p ≤ 0.05) egg weight, while yolk weight remained constant. …”

“…Similarly, Sosin et al (2006) also indicated reduced egg weight when layers were fed linseed. Bean & Leeson (2003) found yolk weight reduction in layers consuming linseed, whereas Sosin et al (2006) reported that feeding linseed to layers had no effect on the yolk weight. Considering these contradictory results, the effects of linseed feeding on layer performance needs to be further evaluated.…”

“…In a trial, diets containing 20% linseed reduced egg weight (Beynen, 2004). Similarly, Sosin et al (2006) also indicated reduced egg weight when layers were fed linseed. Bean & Leeson (2003) found yolk weight reduction in layers consuming linseed, whereas Sosin et al (2006) reported that feeding linseed to layers had no effect on the yolk weight.…”