The Effects of Dietary Inclusion of Bilberry and Walnut Leaves in Laying Hens’ Diets on the Antioxidant Properties of Eggs

Abstract

The purpose of this study was to examine the effects of dietary inclusion of walnut and bilberry leaves (WL and BL), as sources of natural antioxidants in poultry diets, on the enrichment of antioxidant nutrients in the egg yolk and on the susceptibility of the yolk to lipid peroxidation during storage. The experiment was conducted on 32-week-old TETRA SL LL laying hens, which were assigned to three dietary treatments with 30 birds each. Each treatment was replicated 10 times with three chicks per replicate pen. Experimental dietary treatments differed from control diet (C) by addition of 0.5% BL supplement or 1% WL supplement. The phytoadditives were not significant contributors to the productive parameters. The addition of BL and WL in laying hens’ diets significantly increased the total polyphenol content, and the zinc, lutein and zeaxanthin concentrations in the egg yolks. In regards to the oxidative stability parameters, a significant decrease in the concentrations of primary oxidation products formed in the egg yolk of experimental groups was seen, proving an efficient inhibition effect of the phytoadditives on peroxyl radical formation. A significant correlation was observed between primary oxidation products and total polyphenol content of the egg yolks, where zinc, lutein and zeaxanthin are the bioactive compounds that inhibit the formation of secondary oxidation products.

Effects of Supplementing Grape Pomace to Broilers Fed Polyunsaturated Fatty Acids Enriched Diets on Meat Quality

“…The total polyphenol content of extracts was determined spectrophotometrically according to the method described by Untea et al [ 26 ]. For the sample extraction, the Folin-Ciocalteu reagent was used and the absorption was performed at 732 nm.…”

“…The total antioxidant capacity of the extracts was determined using the phosphomolybdenum method [ 26 ]. The absorbance was performed at 695 nm and the results were expressed as ascorbic acid equivalents per gram of dried sample (mmol ascorbic acid equivalent/g).…”

“…The oxidative stability of the meat was determined by means of primary lipid degradation parameters, dienes and conjugated trienes, respectively by secondary parameters, represented by the values of p-anisidine and those of thiobarbituric acid-reactive substances (TBARS), according to the method described by Untea et al [ 26 ]. The lipid peroxidation parameters were spectrophotometrically determined by using a V-530 Jasco (Japan Servo Co. Ltd., Japan) spectrophotometer.…”

Effect of dietary orange and grapefruit peel on growth performance, health status, meat quality and intestinal microflora of broiler chickens

“…The total antioxidant capacity of the vegetal extracts was based by the reaction between the sample solution with reagent solution (0.6 M sulphuric acid, 28 mM sodium phosphate and 4 mM ammonium molybdate) and the absorbance recorded at 695 nm. The method used for determination was described by Untea et al (2020).…”

“…The total polyphenols content of plants methanolic extract (1 g of dried powder in 10 mL of methanol 80%) was measured spectrophotometrically according to the Folin-Ciocalteu's method, as described by Untea et al 2020. Gallic acid was used for calibration curve and the results were expressed as mg Gallic acid equivalents per gram sample (mg GAE/g).…”