Bioavailability of lutein in corn distillers dried grains with solubles relative to lutein in corn gluten meal based on lutein retention in egg yolk

Carotenoid enrichment in eggs: From biochemistry perspective

The emergence of safe and functional eggs for consumer acceptance has gained focus. The production of carotenoid-enriched eggs has received attention due to its multifunctional biological properties. Nutritional modification of laying hens' diet can be a strategy to produce such eggs. This review presents the chemistry of carotenoids in nature and eggs, the accumulation process of carotenoids into eggs, and the functions of carotenoids in eggs. Our findings showed that carotenoids can be deposited into the egg and contribute to improving its nutritive value. The biosynthesis, chemical structure, and metabolism pathways of carotenoids lead to the deposition of carotenoids into eggs in their original or metabolized forms. Also, some factors modulate the efficiency of carotenoids in fowls before accumulation into eggs. Carotenoid-enriched eggs may be promising, ensuring the availability of highly nutritive eggs. However, further studies are still needed to comprehend the full metabolism process and the extensive functions of carotenoids in eggs.

Effect of dietary concentrations of metabolizable energy and neutral detergent fiber on productive performance, egg quality, fatty liver incidence, and hepatic fatty acid metabolism in aged laying hens

The objective of the current experiment was to investigate the effect of dietary concentrations of ME and neutral detergent fiber (NDF) on productive performance, egg quality, fatty liver incidence, and hepatic fatty acid metabolism in aged laying hens. A total of three hundred twenty 75-wk-old Hy-Line Brown laying hens were allotted to 1 of 4 dietary treatments with 8 replicates. Each replicate consisted of 10 consecutive cages with 1 hen per cage. The experiment was conducted using a completely randomized design with 2 × 2 factorial arrangement consisting of 2 levels of ME (normal [commercially recommended AME_n levels; 2,730 kcal/kg] and low [50 kcal/kg reduction in AME_n; 2,680 kcal/kg]) and 2 levels of NDF (low [9.01 and 9.61%; normal-ME and low-ME diets_, respectively] and high [12.57 and 13.42%; normal-ME and low-ME diets_, respectively]) in the diet. The diets and water were provided to hens on an ad libitum basis for 12 wk. Results indicated that no interactions between dietary concentrations of ME and NDF were observed for all measurements except for egg yolk color, eggshell thickness, and 2 hepatic gene expressions (i.e., carnitine palmitoyl transferase 1A and malic enzyme). For the main effects, increasing NDF concentrations in diets increased (P < 0.05) feed intake without affecting other productive performance. Hens fed normal-ME and high-NDF diets showed the darkest (P < 0.05) egg yolk color among those fed treatment diets, showing an interaction (P < 0.05). Increasing NDF concentrations in low-ME diets did not influence eggshell thickness, but those in normal-ME diets increased eggshell thickness in laying hens, showing an interaction (P < 0.05). For the main effects, increasing concentrations of dietary NDF or ME reduced (P < 0.05) hepatic fat concentrations with decreasing expressions in several genes related to fatty acid synthesis. In conclusion, increasing NDF concentrations in commercially-recommended ME diets decrease hepatic fat concentrations in aged laying hens, and therefore, may have a preventative effect on the fatty liver development in aged laying hens.

Effect of different sources and inclusion levels of dietary fat on productive performance and egg quality in laying hens raised under hot environmental conditions

Objective

This experiment aimed to investigate the effect of different sources and inclusion levels of dietary fat on productive performance and egg quality in laying hens raised under hot environmental conditions.

Method

A total of 480 Hy-Line Brown laying hens at 31 wk of age were randomly allotted to 1 of 5 experimental diets. The control diet contained 2,800 kcal/kg AMEn with no fat addition. Four additional diets were prepared by adding 2.0 or 4.0% of animal fat (AF) or soybean oil (SO). Energy and nutrient concentrations were consistent among all diets. Diets were fed to hens for 4 weeks. Average daily room temperature and humidity were 26.7 ± 1.52°C and 77.4 ± 4.50%. The heat stress index was approximately 76, indicating that hens were raised under heat stress conditions.

Results

Final BW was greater (p<0.05) for hens fed diets containing 2.0 or 4.0% AF than for those fed the control diet or diets containing 2.0 or 4.0% SO. The BW gain and feed intake were greater (p<0.05) for hens fed diets containing additional AF or SO than those fed the control diet. Eggshell thickness were the greatest (p<0.05) for hens fed the control diet, but the least (p<0.05) for hens fed diets containing 4.0% SO. Egg yolk color was the greatest (p<0.05) for hens fed to the control diet, but the least (p<0.05) for hens fed diets containing 4.0% SO.

Conclusion

Inclusion of supplemental fat (AF and SO) in diets exhibits preventative effects on BW loss for hens raised under hot environmental conditions when energy and nutrient concentrations in diets were maintained. The effects were greater for AF than for SO. However, inclusion of supplemental fat in diets decreases eggshell thickness and egg yolk yellowness, possibly due to a reduction in Ca absorption and intake of egg yolk colorants.

Effects of corn dried distillers' grains with solubles on performance, egg quality, yolk fatty acid composition and oxidative status in laying ducks

The study investigated the effects of increasing content of corn distillers' dried grains with solubles (DDGS) in the diets of laying ducks on oxidative status, laying performance, egg quality, and egg yolk fatty acid composition. Longyan females (1080) with similar BW at 17 wk of age were randomly assigned to 6 treatment groups, each consisting of 6 replicates of 30 birds. The basal diet (I) was a typical corn-soybean ration while the experimental diets (II to VI) substituted corn DDGS for soybean meal and wheat bran and a small reduction of corn. The level of substitution in diets (II to VI) was 6%, 12%, 18%, 24% and 30%. The experiment lasted for 18 wk. Average egg weight decreased linearly as the level of corn DDGS inclusion increased (P < 0.001). Haugh unit, albumen weight, and proportion declined as linear responses to corn DDGS substitution (P < 0.05), but yolk color linearly increased (P < 0.001); the proportions of oleic (C18:1) and total monounsaturated fatty acids in egg yolk linearly decreased with increasing corn DDGS and many of the key polyunsaturated fatty acids (PUFAs) like linoleic (C18:2n-6), arachidonic (C20:4n-6) and α-linolenic (C18:3n-3) acids linearly increased (P < 0.001), but not those of eicosapentaenoic (C20:5n-3) and docoshexaenoic (C22:6n-3) acids. The PUFAs n-6/n-3 ratio linearly increased with increasing corn DDGS level (P < 0.001). Increasing corn DDGS linearly increased hepatic expression of GPX1, HO-1, and Nrf2 and hepatic activity of GSH-Px and the liver content of MDA (P < 0.001). There were no treatment effects on egg production, egg mass, feed conversion ratio, eggshell thickness, strength, and yolk cholesterol content (P > 0.05). In conclusion, the current study indicates that the use of corn DDGS is possible as a replacement, primarily for soybean meal at levels up to 18% in the diets of laying ducks without affecting laying performance, egg quality, and antioxidant status. Increasing amounts of corn DDGS linearly increased egg yolk concentrations of key fatty acids like like C18:2n-6 and C18:3n-3 and the antioxidant enzyme activity of GSH-Px through the Nrf2 pathway to avoid oxidative stress.

Effect of dietary β-mannanase on productive performance, egg quality, and utilization of dietary energy and nutrients in aged laying hens raised under hot climatic conditions

Objective

The objective of this experiment was to investigate the effect of dietary β-mannanase on productive performance, egg quality, and utilization of dietary energy and nutrients in aged laying hens raised under hot climatic conditions.

Methods

A total of 320 84-wk-old Hy-line Brown aged laying hens were allotted to one of four treatments with eight replicates in a completely randomized design. Two dietary treatments with high energy (HE; 2,800 kcal/kg nitrogen-corrected apparent metabolizable energy [AME_n]) and low energy (LE; 2,700 kcal/kg AME_n) were formulated. Two additional diets were prepared by adding 0.04% (MN4) or 0.08% β-mannanase (MN8) to LE treatment diets. The feeding trial was conducted for 28 d, covering a period from July to August in South Korea. The average daily room temperature and relative humidity were 29.2°C and 83%, respectively.

Results

Productive performance, egg quality, and cloacal temperature were not influenced by dietary treatments. The measured AME_n values for MN8 diets were similar to those for HE diets, which were greater (p<0.05) than those for LE and MN4 diets. However, the AME_n values for MN8 diets did not differ from those for LE and MN4 diets.

Conclusion

The addition of β-mannanase to low energy diets increases energy values for diets fed to aged laying hens. However, this increase has little positive impacts on performance and egg quality. These results indicate that dietary β-mannanase does not mitigate the heat stress of aged laying hens raised under hot climatic conditions.