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Effects of dietary conjugated linoleic acid on fatty acid composition and cholesterol content of hen egg yolks.
Br J Nutr. 2003 Jul; 90(1):93-9.BJ

Abstract

The main objectives of the present study were to determine the effect of dietary conjugated linoleic acid (CLA) isomers on the fatty acid composition and cholesterol content of egg-yolk lipids. Forty-five 25-week-old laying hens were randomly distributed into five groups of nine hens each and maintained in individual laying cages, throughout 12 weeks of the experiment. They were assigned to the five treatments that consisted of commercial layer diets containing 0, 5, 10, 15 or 20 g pure CLA/kg. Feed intake of hens varied little and insignificantly. Egg mass was uniformly lower (P<0.05) in the hens fed the CLA-enriched diets. Feed conversion efficiency, when expressed per kg eggs, was impaired (P<0.05), although without obvious relation to the dietary CLA concentration. Feeding the CLA-enriched diets resulted in gradually increasing deposition of CLA isomers (P<0.01) in egg-yolk lipids. Saturated fatty acids were increased (P<0.01) and monounsaturated fatty acids decreased (P<0.01). Polyunsaturated fatty acids (PUFA), when expressed as non-CLA PUFA, were also significantly decreased (P<0.01). The most striking effects (P<0.01) were observed for palmitic (16 : 0) and stearic (18 : 0) acids, which increased from 23.6 to 34 % and from 7.8 to 18 %, respectively. On the other hand, oleic acid (18 : 1n-9) decreased from 45.8 to 24.3 %. Among non-CLA PUFA, linoleic (18 : 2n-6) and alpha-linolenic (18 : 3n-3) acids were strongly (P<0.01) decreased, from 14.2 to 7.7 % and from 1.3 to 0.3 %, respectively. The same was true for arachidonic (20:4n-6) and docosahexaenoic (22 : 6n-3) acids. The cholesterol content of egg yolks, when expressed in mg/g yolk, was not affected by the dietary CLA concentrations. In conclusion, unless the adverse effects of CLA feeding to laying hens on the fatty acid profile of egg yolks are eliminated, the CLA-enriched eggs cannot be considered functional food products.

Authors+Show Affiliations

Department of Animal Nutrition, Institute of Animal Production, 32-084 Balice, Poland.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12844380

Citation

Szymczyk, Beata, and Paweł M. Pisulewski. "Effects of Dietary Conjugated Linoleic Acid On Fatty Acid Composition and Cholesterol Content of Hen Egg Yolks." The British Journal of Nutrition, vol. 90, no. 1, 2003, pp. 93-9.
Szymczyk B, Pisulewski PM. Effects of dietary conjugated linoleic acid on fatty acid composition and cholesterol content of hen egg yolks. Br J Nutr. 2003;90(1):93-9.
Szymczyk, B., & Pisulewski, P. M. (2003). Effects of dietary conjugated linoleic acid on fatty acid composition and cholesterol content of hen egg yolks. The British Journal of Nutrition, 90(1), 93-9.
Szymczyk B, Pisulewski PM. Effects of Dietary Conjugated Linoleic Acid On Fatty Acid Composition and Cholesterol Content of Hen Egg Yolks. Br J Nutr. 2003;90(1):93-9. PubMed PMID: 12844380.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of dietary conjugated linoleic acid on fatty acid composition and cholesterol content of hen egg yolks. AU - Szymczyk,Beata, AU - Pisulewski,Paweł M, PY - 2003/7/8/pubmed PY - 2003/8/2/medline PY - 2003/7/8/entrez SP - 93 EP - 9 JF - The British journal of nutrition JO - Br. J. Nutr. VL - 90 IS - 1 N2 - The main objectives of the present study were to determine the effect of dietary conjugated linoleic acid (CLA) isomers on the fatty acid composition and cholesterol content of egg-yolk lipids. Forty-five 25-week-old laying hens were randomly distributed into five groups of nine hens each and maintained in individual laying cages, throughout 12 weeks of the experiment. They were assigned to the five treatments that consisted of commercial layer diets containing 0, 5, 10, 15 or 20 g pure CLA/kg. Feed intake of hens varied little and insignificantly. Egg mass was uniformly lower (P<0.05) in the hens fed the CLA-enriched diets. Feed conversion efficiency, when expressed per kg eggs, was impaired (P<0.05), although without obvious relation to the dietary CLA concentration. Feeding the CLA-enriched diets resulted in gradually increasing deposition of CLA isomers (P<0.01) in egg-yolk lipids. Saturated fatty acids were increased (P<0.01) and monounsaturated fatty acids decreased (P<0.01). Polyunsaturated fatty acids (PUFA), when expressed as non-CLA PUFA, were also significantly decreased (P<0.01). The most striking effects (P<0.01) were observed for palmitic (16 : 0) and stearic (18 : 0) acids, which increased from 23.6 to 34 % and from 7.8 to 18 %, respectively. On the other hand, oleic acid (18 : 1n-9) decreased from 45.8 to 24.3 %. Among non-CLA PUFA, linoleic (18 : 2n-6) and alpha-linolenic (18 : 3n-3) acids were strongly (P<0.01) decreased, from 14.2 to 7.7 % and from 1.3 to 0.3 %, respectively. The same was true for arachidonic (20:4n-6) and docosahexaenoic (22 : 6n-3) acids. The cholesterol content of egg yolks, when expressed in mg/g yolk, was not affected by the dietary CLA concentrations. In conclusion, unless the adverse effects of CLA feeding to laying hens on the fatty acid profile of egg yolks are eliminated, the CLA-enriched eggs cannot be considered functional food products. SN - 0007-1145 UR - https://www.unboundmedicine.com/medline/citation/12844380/Effects_of_dietary_conjugated_linoleic_acid_on_fatty_acid_composition_and_cholesterol_content_of_hen_egg_yolks_ L2 - http://ovidsp.ovid.com/ovidweb.cgi?T=JS&amp;PAGE=linkout&amp;SEARCH=12844380.ui DB - PRIME DP - Unbound Medicine ER -