Dietary conjugated linoleic acid with fish oil alters yolk n-3 and trans fatty acid content and volatile compounds in raw, cooked, and irradiated eggs

Abstract

We investigated the effect of dietary conjugated linoleic acid (CLA) along with n-3 polyunsaturated fatty acid (n-3 PUFA) on yolk fatty acid composition and volatile compounds in eggs that were raw (RA), hard-boiled (HB), or hard-boiled, irradiated (HBI, 2.5 kGy). Single Comb White Leghorn laying hens (n = 40) were randomly assigned to one of the four experimental diets containing 0, 0.5, 1.0, or 2.0% CLA. Menhaden oil was used as the source of n-3 PUFA. Eggs collected after 6 wk of feeding were analyzed for fatty acids and volatile compounds. The content of docosahexaenoic acid (C22:6 n-3) was reduced (P < 0.05) in eggs from hens fed the 2.0% CLA diet. Eggs from hens fed 0.5% CLA incorporated the highest concentration of docosahexaenoic acid (P < 0.05) with a concomitant reduction in arachidonic acid (P < 0.05). The yolk contents of cis-9 trans-11 CLA and trans-10 cis-12 CLA increased linearly (P < 0.05) as the dietary CLA supply increased. Total monounsaturates were reduced (P < 0.05) with an increase in saturates in yolk. No difference was observed in the total PUFA content of eggs. Total volatiles were reduced in RA eggs from 1.0 and 2.0% CLA diets. 2-Propanone, hexane, and methyl cyclopentane were the major volatiles in RA eggs and were reduced by dietary CLA at 1.0 and 2.0%. Acetaldehyde, pentane, propanol, acetic acid methyl ester, acetic acid ethyl ester, propionic acid methyl ester, 2-methylmethyl propionic acid, 2-propanone, and octane were the major volatiles in HB eggs and were reduced by 2.0% CLA (P < 0.05). No difference was observed in the acetaldehyde, pentane, propanol, acetic acid ethyl ester, octane, or total volatile content of HBI eggs.

Effects of dietary conjugated linoleic acid isomers and vitamin E on fatty acid composition and cholesterol content of hen egg yolks

“…Total PUFA content was not markedly altered in egg yolk lipids whereas that of non-CLA PUFA was substantially (P<0.01) decreased (Table 4). Similar, changes in fatty acid composition of eggs were observed in earlier studies (Schäfer et al, 2001;Cherian et al, 2002;Szymczyk and Pisulewski, 2003). The observation that the proportions of SFA in egg yolk lipids increased, whereas those of MUFA and non-CLA decreased, with CLA feeding, is of special interest.…”

“…Interestingly, CLA-enriched milk fat has been demonstrated to reduce the number of chemically-induced mammary tumors in female rats (Ip et al, 1999) and to inhibit the growth of human breast and colon cancer cell lines (Miller et al, 2003). Consequently, animal nutrition strategies have been developed to enrich foods of animal origin, including eggs (Jones et al, 2000;Schäffer et al, 2001;Cherian et al, 2002;Szymczyk and Pisulewski, 2003) with CLA isomers. The mechanisms of the above health-related effects of CLA isomers, such as anticarcinogenic and antiatheroslerotic action, have been attributed to their alleged antioxidant properties (Ha et al, 1990).…”

Effect of conjugated linoleic acid, high-oleic sunflower oil and fish oil dietary supplementation on laying hen egg quality

“…Even supplementation with as little as 5 g kg -1 can lead to a 33-46% increase in total yolk saturated fatty acids and reduce the level of total monounsaturated fatty acids to below 300 g kg -1 (Aydin et al, 2001;Cherian et al, 2002;Szymczyck and Pisulewski, 2003;Álvarez et al, 2004b). As a consequence, the hardness of the yolk of cooked eggs increases and the sensorial quality (for consumers) is reduced Aydin et al, 2001Aydin et al, , Álvarez et al, 2004a.…”

“…Other studies indicate that CLA supplementation of fish oil-(FO) or flaxseed-added diets does not reduce and can even increase total n-3 fatty acid deposition in the yolk fat (Du et al, 2000;Cherian et al, 2002;Raes et al, 2002;Álvarez et al, 2004b). Further, CLA is an effective antioxidant (Ha et al, 1990), and might reduce the off-flavours associated with the feeding of f ish oil (Herber-McNeill and Van Elswyk, 1998;Leeson et al 1998).…”

Effects of conjugated linoleic acid addition on its deposition in eggs of laying hens, fed with no other fat source

“…Previous work Du et al, , 2000Jones et al, 2000;Aydin et al, 2001;Schaffer et al, 2001;Cherian et al, 2002;Raes et al, 2002;Szymczyck and Pisulewski, 2003) has shown that it is possible to produce CLA-enriched eggs through CLA supplementation of layer diets. The relationship between CLA concentrations in egg yolk and feed was almost linear up to levels of inclusion of CLA in the diet of 5%.…”