ABSTRACT
Healthy diets are necessary for both humans and animals, including poultry. These diets contain various nutrients for maintenance and production in laying hens. Therefore, research was undertaken to explore the efficiency of various dietary flaxseed sources on the n-3 deposition in the egg yolk and gene expression in laying hens. Five dietary groups were analyzed, i.e., (i) a corn-based diet with no flaxseed (FS) as a negative control (NC), (ii) a wheat-based diet supplemented with 10% whole FS without multi-carbohydrase enzymes (MCE) as a positive control (PC), (iii) ground FS supplemented with MCE (FS), (iv) extruded flaxseed meal was supplemented with MCE (EFM), (v) flaxseed oil supplemented with MCE (FSO). Results indicated that egg weight was highest in the NC, FS, EFM, and FSO groups as compared to PC in the 12th week. Egg mass was higher in enzyme supplemented groups as compared to the PC group, but lower than NC. In the 12th week, the HDEP (hen day egg production) was highest in the FS and EFM groups as compared to FSO, PC, and NC. The FCR (feed conversion ratio) was better in enzyme supplemented groups as compared to the PC group. Enzyme addition enhanced the egg quality as compared to PC in the 12th week. The HDL-C (high-density lipoprotein cholesterol) was increased, while LDL-C (low-density lipoprotein cholesterol), VLDL-C (very-low-density lipoprotein cholesterol), TC (total cholesterol), and TG (total triglycerides) were reduced in the enzyme supplemented groups as compared to PC and NC. The FSO deposit more n-3 PUFA and docosahexaenoic acid (DHA) in the egg yolk as compared to FS and EFM groups. The expression of ACOX1, LCPT1, FADS1, FADS2, and ELOV2 genes were upregulated, while PPAR-α was downregulated in the FSO group. The LPL mRNA expression was upregulated in the FS, EFM, and FSO groups as compared to the PC and NC groups. It was inferred that FSO with enzymes at 2.5% is cost-effective, improves the hen performances, upregulated the fatty acid metabolism and ß-oxidation genes expression, and efficiently deposits optimal n-3 PUFA in the egg as per consumer's demand.
ABSTRACT
Ninety-six brown Lohmann laying hens were equally assigned into four groups with six replicates. Hens within the control group were fed a corn-soybean-based diet supplemented with 4% linseed oil. Two other groups were given the same diet further supplemented with 5 or 10 g ground olive leaves/kg feed, while the diet of the fourth group was further supplemented with 200 mg α-tocopheryl acetate/kg. Supplementing diets with olive leaves had no effect on egg production, feed intake and egg traits. Eggs collected 28 days after feeding the experimental diets were analysed for lipid hydroperoxides and malondialdehyde (MDA) content, fatty acid profile, α-tocopherol concentrations and susceptibility to iron-induced lipid oxidation. Olive leaves were also analysed for total and individual phenolics, and total flavonoids, whereas their antioxidant capacity was determined using both the DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2-azinobis3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity assays. Results showed that neither α-tocopheryl acetate nor olive leaves supplementation exerted (p>0.05) any effect on the fatty acid composition of n-3 eggs. Supplementing the diet with 5 g olive leaves/kg had no (p>0.05) effect on the hydroperoxide levels of n-3 eggs, while supplementing with 10 g olive leaves/kg or 200 mg α-tocopheryl acetate/kg, the lipid hydroperoxide levels were reduced (p≤0.05) compared to control. However, although hydroperoxides were reduced, MDA, a secondary lipid oxidation product, was not affected (p>0.05). Iron-induced lipid oxidation increased MDA values in eggs from all groups, the increase being higher (p≤0.05) in the control group and the group supplemented with 5 g olive leaves/kg. The group supplemented with 10 g olive leaves/kg presented MDA values lower (p≤0.05) than the control but higher (p≤0.05) than the α-tocopheryl acetate group, which presented MDA concentrations lower (p≤0.05) than all other experimental diets at all incubation time points.