title: The deposition of conjugated linoleic acids in eggs of laying hens fed diets varying in fat level and fatty acid profile.
abstract: The objective of this study was to investigate the incorporation of conjugated linoleic acid (CLA) into eggs and its effect on the fatty acid metabolism when layers are fed diets with different fat sources and fat levels. Layers were fed either a low fat diet (LF) or one of three high fat diets based on soybean oil (SB), animal fat (AF) or flaxseed oil (FSO). CLA was added at a concentration of 1 g/100 g feed from two different CLA premixes with a different CLA profile. For the trial, 144 laying hens were allocated to 12 treatments (4 basal fat sources x 3 CLA treatments) with 3 replicates of 4 hens each. No significant differences were observed in feed intake, egg weight, feed conversion or laying rate between chickens fed control and CLA-supplemented diets. Differences in yolk fat, cholesterol or yolk color were not clearly related to the dietary CLA. However, the supplementation of CLA to the diets had clear effects on the fatty acid composition, i.e., a decrease in monounsaturated fatty acids (MUFA) and an increase in saturated fatty acids (SFA) was observed, whereas the polyunsaturated fatty acids (PUFA) content were essentially unaffected. The results suggest that CLA may influence the activity of the desaturases to a different extent in the synthesis of (n-6) and (n-3) long-chain fatty acids. These effects of CLA depend on the level of (n-6) and (n-3) fatty acids available in the feed. The apparent deposition rate (%) is clearly higher for the c9, t11 isomer than for the t10, c12 isomer. Adding CLA to layers diets rich in (n-3) fatty acids produces eggs that could promote the health of the consumer in terms of a higher intake of (n-3) fatty acids and CLA.
authors.affiliation: Ghent University, Faculty of Agricultural and Applied Biological Science, Department of Animal Production, Proefhoevestraat, 10-9090 Melle, Belgium.
authors.forename: Katleen
authors.initials: K
authors.lastname: Raes
authors.forename: Gerard
authors.initials: G
authors.lastname: Huyghebaert
authors.forename: Stefaan
authors.initials: S
authors.lastname: De Smet
authors.forename: Lode
authors.initials: L
authors.lastname: Nollet
authors.forename: Sven
authors.initials: S
authors.lastname: Arnouts
authors.forename: Daniel
authors.initials: D
authors.lastname: Demeyer
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D019587:Dietary Supplements; D004530:Egg Yolk / Q000737:chemistry*; D004531:Eggs / Q000032:analysis; D044943:Fatty Acid Desaturases / Q000187:drug effects / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000096:biosynthesis*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000032:analysis* / Q000096:biosynthesis*; D005260:Female; D007536:Isomerism; D019787:Linoleic Acid / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism*; D008043:Linseed Oil / Q000008:administration & dosage; D011897:Random Allocation; D013024:Soybean Oil / Q000008:administration & dosage
chemical_list: D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D013024:Soybean Oil; D008043:Linseed Oil; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases