Hen performance, egg quality, and the sensory evaluation of eggs from SCWL hens fed dietary flax

The combined influence of dietary flaxseed variety, level, form, and storage conditions on egg production and composition among vitamin E-supplemented hens

Trial 1 tested the effects of ground vs whole flaxseed at dietary levels of 5, 10, or 15% compared to a corn-soybean or fish oil control on egg production of Leghorn hens over a period of 8 wk. Dietary flaxseed decreased feed consumption, weight gain, and egg weights compared to the control diets; however, flaxseed and fish oil significantly improved egg production (88.9 and 93.0%, respectively) compared to the control (83.1%). Incorporation of linolenic acid (C18:3n-3) into the egg increased linearly as the level of dietary flaxseed increased (2.31, 4.18, or 6.83% of the yolk fatty acids for 5, 10, and 15% flaxseed diets, respectively). In Trial 1, flaxseed and fish oil significantly increased percentage white and decreased percentage yolk compared to the control treatment but had no effects on egg cholesterol. Trial 2 was a factorial design of varieties of flaxseed (brown vs golden), types (ground vs whole), levels of dietary vitamin E (27 vs 50 IU/kg), and feed storage temperatures (4 vs 21 C) fed to hens for 6 wk. Brown flaxseed significantly increased egg weight and egg production compared to the golden variety. There was no difference in whole vs ground flaxseed for measured production variables. Vitamin E (50 IU) significantly improved egg production (96.1 vs 94.3%) compared to 27 IU. Storage temperature of flaxseed did not significantly affect any production variables. In conclusion, dietary flaxseed can be safely added whole to layer diets up to 15% without any detrimental effects on hen-day egg production. Levels of 10 to 15% flaxseed yield eggs with 4 to 7% yolk n-3 fatty acids, respectively, making these eggs rich sources of n-3 fatty acids.

Dietary oils with added tocopherols: effects on egg or tissue tocopherols, fatty acids, and oxidative stability

The effect of dietary oils [menhaden (MO), flax (FL), palm (PO), and sunflower oils (SF)] with added tocopherols on the tocopherol deposition, fatty acid composition, and thiobarbituric acid (TBA) values of egg or tissues (liver, adipose tissue, white meat, and dark meat) were examined. Addition of tocopherols increased (P < 0.05) the total egg or tissue tocopherol content. The enhancement of total tocopherols in the different tissues in the order of magnitude were egg yolk > liver > adipose tissue > dark meat > white meat. Dark meat contained higher (P < 0.05) total tocopherols than white meat. Dietary MO or FL resulted in a significant (P < 0.05) incorporation of C20:5 n-3 and c22:6 n-3 with a concomitant reduction in C20:4 n-6 in liver, egg, white meat and dark meat. Dietary SF resulted in a significant (P < 0.05) incorporation of C18:2 n-6 and C20:4 n-6 in all the tissues. Addition of PO did not result in any change in the yolk saturated fatty acid content. The content of monounsaturated fatty acids were greater (P < 0.05) in all the tissues from PO diets than in diets with other oils. Dietary tocopherols resulted in a significant increase (P < 0.05) in the content of C20:5 n-3 and C22:6 n-3 in the yolk, adipose tissue, and white meat from birds fed MO + T diets. Inclusion of tocopherols resulted in a significant (P < 0.05) reduction in TBA values in eggs, in liver for MO and FL diets, and in dark and white meat for the MO diet. Tocopherol supplementation did not result in any change in TBA values in the PO diet.

Effects of dietary alpha-linolenic acid and strain of hen on the fatty acid composition, storage stability, and flavor characteristics of chicken eggs

A study was conducted to determine the effect of dietary alpha-linolenic acid on the fatty acid compositions of egg yolk lipids, tocopherols, and internal quality of raw eggs during storage and the sensory characteristics of hard-boiled eggs from six different laying hen strains. Laying hens (total 300 birds, 72 wk old) from six strains (Rhode Island Red, Barred Plymouth Rock, New Hampshire, Light Sussex, Brown Leghorn, and White Leghorn) were distributed in 12 floor pens (2 pens per strain, 25 birds per pen) with male roosters. One of the pens for each strain was fed with tallow-based control diet and another was assigned with 3% alpha-linolenic acid (LNA) enriched diet with 120 U of mixed tocopherol/kg diet for 3 mo. Ten eggs from each pen were collected every day after 2 wk with the experimental diets, and stored in a cold room at 4 C up to 4 wk. Total lipids, fatty acid compositions, Haugh units, and tocopherols of egg yolk were determined once a week during the 4-wk storage periods. Sensory studies were also conducted using the eggs stored for 2 wk at 4 C. Dietary LNA increased the amount of n-3 fatty acids (6.5%) in total lipid, and over 70% was C18:3n3, and the rest was C22:6n3 (20 to 25%) and C22:5n3 (5 to 10%). Only minor differences in fatty acids among strains were observed. The differences and the changes in tocopherols during storage periods by strain and diet appeared randomly and lacked consistency.(ABSTRACT TRUNCATED AT 250 WORDS)