Effect of grass-clover forage and whole-wheat feeding on the sensory quality of eggs

Evaluation of Physical Egg Quality Parameters of Commercial Brown Laying Hens Housed in Five Production Systems

This study evaluates the effect of housing environment on the egg quality characteristics of brown egg layers as many different environments are currently used in the industry. Battery cages, barren colony cages, enriched colony cages, cage-free, and free-range environments were evaluated. Overall, all egg quality measurements were affected by housing environment (p < 0.01) except for vitelline membrane strength, elasticity, and egg solids. Eggshells and yolks were lightest in barren colony cages and darkest from free-range hens (p < 0.0001). Free-range eggs were heavier than eggs from all other environments (p < 0.0001). Cage-free eggs had lower albumen height and Haugh units than other environments (p < 0.0001). Lastly, cage-free and free-range eggs had stronger eggshells than the other environments (p < 0.0001), and free-range eggs had more elastic eggshells than eggs from conventional battery cages and barren colony cages (p < 0.01). Access to the range seemed to give free-range hens different nutritional advantages, which allowed for the darker yolks and shells. Furthermore, eggs from barren colony cages seemed to exhibit more negative characteristics. Simply adding enrichments to colony cages did not improve or detract from egg quality. From this research, it appears that, as the industry moves toward extensive environments, the egg quality of brown egg layers will improve.

Laying Performance, Egg Quality Characteristics, and Egg Yolk Fatty Acids Profile in Layer Hens Housed with Free Access to Chicory- and/or White Clover-Vegetated or Non-Vegetated Areas

Simple Summary

Outdoor-based systems can improve the product quantity and quality in laying hens. This study investigated the laying performance and several egg quality characteristics in layer hens fed on a conventional diet with free access to a soil area (control, C), a chicory (CI)- or white clover (TR)-vegetated area, or a CI and TR mixture (MIX)-vegetated area. The C hens consumed more concentrate feed, without affecting the laying rate, than did TR and MIX hens. Herbage intake (HI) of the TR and MIX hens was higher than that of the CI birds. The C hens produced eggs with thicker shells than the CI, TR, and MIX hens. The decrease in the feed intake and the improvement in fatty acid (FA) profiles of the egg yolk was related to the HI. Concerning the TR and MIX vegetation, the FA composition of herbage contributed to the production of eggs with preferred FA attributes, such as polyunsaturated FAs and a favourable n-6 to n-3 ratio.

Abstract

This study investigated the laying performance, egg quality, and egg yolk fatty acids (FAs) and cholesterol content in layer hens housed with free access to chicory- and/or white clover-vegetated areas. During a 16-week study, 400 Lohmann Brown hens (32 weeks old) housed with free outdoor access were allocated randomly into four groups, each with four replicates of 25 hens. Control hens were fed a conventional diet with free access to a soil area (C), whereas other hens were fed on a conventional diet with free access to a chicory (CI)- or white clover (TR)-vegetated area or a CI and TR mixture (MIX)-vegetated area. The C hens consumed more concentrate feed (p = 0.018) than the TR and MIX hens, which had a higher herbage intake than the CI birds (p < 0.001). The C hens produced eggs with a thicker shell than those in the other treatment groups (p = 0.013). Compared with C, the saturated FAs of egg yolk decreased for MIX (p = 0.010). The polyunsaturated FAs were higher in the MIX eggs than in the C and TR eggs (p < 0.001). Although FAs were distributed in all quadrants of the principal component analysis (PCA), three main FA profiles could be identified based on the loadings of natural groupings in the PC2 versus PC1 plot. The present study shows clear evidence for the contribution of herbage to the hen diet without affecting laying performance. In addition, the FA composition of the CI and MIX vegetation contributed to the production of eggs with preferred FA attributes, such as polyunsaturated FAs and a favourable n-6 to n-3 ratio.

Plant Carotenoids as Pigment Sources in Laying Hen Diets: Effect on Yolk Color, Carotenoid Content, Oxidative Stability and Sensory Properties of Eggs

The aim of this study was to evaluate the effect of a supplementation diet for hens consisting of dried basil herb and flowers of calendula and dandelion for color, carotenoid content, iron-induced oxidative stability, and sensory properties of egg yolk compared with commercial pigment (control) and marigold flower. The plant parts were supplemented in diets at two levels: 1% and 3%. In response to dietary content, yolks from all diets differed in carotenoid profile (p < 0.001). The 3% supplementation level resulted in a similar total carotenoid content as the control (21.25 vs. 21.79 μg/g), but by 3-fold lower compared to the 3% marigold (66.95 μg/g). The tested plants did not achieve yolk color fan values as the control (13.47) or 3% marigold (11.47), and among them, calendula had the highest values (9.73). Despite the low carotenoid content in diets supplemented with basil herb, iron-induced malondialdehyde (MDA) concentration was low as for marigold (on average 106.83 vs. 92.68 ng/g after 250 min). The treatments differed in sensory color scores for fresh and hard-boiled yolks and flavor while other sensory properties were similar. In conclusion, the supplementation of plants in a hen diet may result in yolks containing carotenoids and other compounds showing a high antioxidant effect.

Saltbush (Atriplex nummularia and A. amnicola) as potential plants for free-range layer farms: consequences for layer performance, egg sensory qualities, and excreta moisture

Highly adapted plant species suited to low rainfall conditions need to be considered for free-range poultry farms, particularly in marginal rainfall areas. A group of suitable plants are the saltbushes, in particular old man saltbush (Atriplex nummularia) can provide shelter, shade, and possibly forage. The first experiment examined whether hens eat old man saltbush while ranging. Free-range Hy-Line Brown layer hens were provided saltbush or "no" saltbush on the outdoor range throughout 11 wk of early production (16 to 27 wk). The quantity of saltbush eaten by the hens was determined by the n-alkane method. Hen interactions with saltbush were video recorded, and hen live weight, feed intake, egg production, and egg quality were measured. Hens ate the saltbush at 5% of their dietary dry matter intake. This level of saltbush intake had no influence on egg production. The video footage revealed hens actively pecked at the saltbush. The second experiment investigated the consequences of hens diluting their diet by eating increased levels of River saltbush (Atriplex amnicola). Air-dried, hammer-milled river saltbush was mixed and pelleted into a standard commercial layer diet at the following levels; 0 (control), 5, 10, 15, and 20%. Hy-Line Brown layer hens were fed the diets for 28 D (32 to 35 wk of age). Seventy-five hens were housed in individual cages, with 15 hen replicates per diet. The saltbush had no significant impact on egg production, hen live weight, or feed intake. Excreta moisture increased significantly (P < 0.001) with increased saltbush (5, 10, 15, and 20%) in the diet. Furthermore, high saltbush eggs (20%) had significantly stronger egg yolk color (P = 0.006) and thicker egg shells (P < 0.001) compared to the control eggs. Consumers were presented with the eggs from the second experiment and they preferred the high saltbush eggs (20%). In conclusion, saltbush would be a valuable plant on free-range poultry farms to provide shade and shelter, especially in those areas with marginal rainfall.

The effects of kale (Brassica oleracea ssp. acephala), basil (Ocimum basilicum) and thyme (Thymus vulgaris) as forage material in organic egg production on egg quality

1. In organic egg production, forage material as part of the diet for laying hens is mandatory. The purpose of the present study was to examine the effect of feeding with forage materials including maize silage, herbs or kale on egg production and various egg quality parameters of the shell, yolk colour, egg albumen, sensory properties, fatty acid and carotenoid composition of the egg yolk. 2. A total of 5 dietary treatments were tested for 5 weeks, consisting of a basal organic feed plus 120 g/hen.d of the following forage materials: 1) maize silage (control), 2) maize silage incl. 15 g/kg basil, 3) maize silage incl. 30 g/kg basil, 4) maize silage incl. 15 g/kg thyme, or 5) fresh kale leaves. Each was supplied to three replicates of 20 hens. A total of 300 hens was used. 3. Feed intake, forage intake and laying rate did not differ with treatment, but egg weight and egg mass produced increased significantly with the kale treatment. 4. The egg shell strength tended to be higher with the kale treatment, and egg yolk colour was significantly more red with the kale treatment and more yellow with basil and kale treatments. The albumen DM content and albumen gel strength were lowest with the thyme treatment. By sensory evaluation, the kale treatment resulted in eggs with less sulphur aroma, higher yolk colour score, and more sweet and less watery albumen taste. Furthermore, the eggs of the kale treatment had significantly higher lutein and β-carotene content. Also, violaxanthin, an orange xanthophyll, tended to be higher in kale and eggs from hens receiving kale. 5. In conclusion, forage material, especially basil and kale, resulted in increased egg production and eggs of high and differentiable quality.