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Dietary supplementation with omega-3 polyunsaturated fatty acids (n-3 PUFAs) for laying hens enriches eggs with these essential fatty acids. However, the enrichment patterns and changes to intact lipids in egg yolk have not been sufficiently revealed. Herein, egg yolk lipids from hens fed with diets supplemented with flaxseed, Schizochytrium sp. residue, or their mixture were comprehensively analyzed using ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). A total of 335 individual lipid species covering 23 (sub)classes were identified and quantified. Distinct n-3 PUFA-lipid profiles were revealed among different groups. Dietary α-linolenic acid (ALA) was mainly deposited in the TAG fraction, whereas synthesized or preformed docosahexaenoic acid (DHA) predominantly existed in the glycerophospholipid form. Furthermore, different lipid species were identified and related lipid pathways after dietary supplementation were analyzed. Collectively, these findings provide us with new knowledge for production, nutritional evaluation, authentication, and application of n-3 PUFA-enriched eggs.

Membrane phospholipids, including phosphatidylcholine (PC) and phosphatidylethanolamine (PE), consist of distinct fatty acids occupying the sn-1 and sn-2 positions, reflecting the highly regulated nature of lipid biosynthesis. However, little is known about the influence of dietary lipids on the positional nature of fatty acids in tissues, including the enrichment of omega-3 polyunsaturated fatty acid (PUFA) in chicken egg yolk phospholipids. This study was undertaken to characterize the PC and PE species in egg lipids derived from Lohmann hens (n=10/treatment) randomly allocated to either a control (no supplementation), a flaxseed oil (FO) or a marine algal oil (MA) diet. Each of the FO or MA diets supplied three levels of total omega-3 PUFA (0.20, 0.40 and 0.60% of diet) that were provided for 6 weeks. A combination of multiplexed mass spectrometry (MS) experiments are used to determine total, isobaric, and position molecules for PC and PE in egg yolk. The distribution of phospholipids in the yolk was predominantly PC over PE (~72 vs. 23%, respectively) across treatments. The longer chain PUFA existed in the sn-2 position in the PC and PE. Although docosahexaenoic acid (22:6) formed isomers with fatty acids 16:0, 18:0 and 18:1; it was preferentially enriched in the egg in combination with 16:0 with both the FO and MA-fed groups in both lipid pools. All 22:6-containing isomers were enriched by ~2-fold more (P < 0.0001) with MA than FO, however, all isomers exhibited a plateau with the FO-fed group. In addition, the MS analyses of PCs revealed several isobaric species containing eicosapentaenoic acid (EPA, 20:5), however, in the PE, EPA formed only one isomer (i.e. in combination with 16:0). These results may assist to elucidate potential aspects regulating the limited enrichment of omega-3 PUFA, particularly EPA and docosahexaenoic acid (22:6) in chicken eggs., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The experiment was conducted to evaluate the effects of five rubber seed oil (RSO) levels (0, 1%, 2%, 4%, and 6%) on hens laying performance, egg quality, and yolks fatty acid composition and cholesterol contents. Three hundred and sixty 30-week-old Lohmann Brown laying hens were allotted to 5 groups. The results showed that the egg production was increased in 4% RSO group (P < 0.05), but egg quality parameters and the contents of dry matter, lipid, and protein in yolks were not influenced among treatments (P > 0.05). Yolk cholesterol contents were reduced in RSO supplemental groups (P < 0.05). The concentration of total n-3 PUFA in yolks increased gradually while the ratio of n-6/n-3 decreased gradually with increasing dietary RSO levels (P < 0.001). In conclusion, dietary RSO supplementation increased yolk n-3 PUFA levels, improved yolk color, and reduced yolk cholesterol contents without negative influence on laying performance parameters., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The effect of hempseed in the diet of laying hens was evaluated at 0, 30, 60 and 90 g/kg concentrations. The aim of the study was to determine the effect of dietary treatment on the performance of hens, the physical characteristics of egg quality, the concentrations of α- and γ-tocopherol and the carotenoid and cholesterol contents of egg yolks, together with the breaking strength of tibial measurements. In light of the obtained results, our study aimed to address the optimal dietary level of hempseed in laying hen diets. Lohmann Brown hens (n = 240) were divided into 4 dietary treatment groups (6 cages per treatment) with 10 hens per cage. The experiment lasted for 12 weeks. The level of nutrients in all diets (wheat-corn) was well balanced. The dietary metabolisable energy was adjusted using rapeseed oil. The addition of 30 g/kg of hempseed to the diet significantly increased (P˂0.001) egg production and egg mass. Alpha-tocopherol increased significantly (P = 0.002) only in the case of the 60 g/kg hempseed level (101 mg/kg dry matter (DM) versus 83 mg/ kg DM in the control group). In contrast, the level of γ-tocopherol increased gradually from 11 mg/kg DM in the control to 29, 39 and 43 mg/kg DM at the 30, 60 and 90 g/kg levels of dietary hempseed, respectively. The concentrations of beta carotene, zeaxanthin and lutein in egg yolks were not influenced by the dietary treatment. Hempseed at 90 g/kg (P = 0.036) decreased egg shell thickness without affecting its strength. The addition of hempseed decreased (P˂0.001) the cholesterol concentration in the egg yolks in all experimental groups. The addition of 30, 60 and 90 g hempseed increased (P˂0.001) the breaking strength of the tibia to 354, 352 and 350 N, respectively, compared to 297 N in the control group. The highest level of hempseed in the diet positively influenced the Ca concentration in the tibia (P = 0.021). The concentration of P in the tibia was negatively affected in the 60 to 90 g/kg hempseed treatments (P˂0.001). Eggs are a significant source of α-tocopherol. Based on our results, there is a possibility for enrichment of egg yolks with γ-tocopherol, with all of its associated health benefits, by the addition of hempseed to the diet of laying hens. Another significant benefit of hempseed is its effect on the breaking strength of the tibia, which can help with crucial problems in the commercial breeding of laying hens., Competing Interests: The authors have declared that no competing interests exist.

Phytogenic additives such as thymol are encountering growing interest in the poultry industry. However, there are still questions concerning dynamics of their bioavailability, biological action, optimal dosage and duration of supplementation needed to achieve meaningful effects, as well as persistence of induced changes after supplement withdrawal. We studied the link between the dynamics of free thymol concentration and the changes in fatty acids composition in quail egg yolk, both during a month-long chronic dietary supplementation and after 3 weeks of supplement withdrawal (post-supplementation). Fifty, 85 days-old, female quail of homogeneous body weights (251±1g) in egg-laying peak were used. To evaluate potential dose-dependent effects, three increasing doses 2, 4, and 6.25 g of thymol/kg of feed (THY2, THY4 and THY6, respectively) and two controls were evaluated (n = 10). In parallel, we assessed the concomitant changes in free thymol excretion, potential liver histopathological changes, and birds´ performance traits. Egg yolk and droppings show a dose-dependent increase in THY concentration after 9 days of supplementation and a decrease after post-supplementation. In egg yolk, these changes were accompanied by reduced saturated fatty acid concentrations achieved by 28 days of supplementation in THY2 and 14 days of supplementation in THY4 and THY6. However, after post-supplementation the aforementioned effect disappeared in THY2 but not in THY4 and THY6. While THY2 failed to increase polyunsaturated fatty acids, THY4 and THY6 increased polyunsaturated fatty acids by day 14 of supplementation and remained increased after post-supplementation. Fatty acids changes induced by thymol are consistent with improved nutritional quality of eggs. No treatment effects were observed in liver histopathology and female performance. Findings suggest that both dose of thymol and duration of supplementation modulate thymol and fatty acids concentrations in egg yolk and thymol concentration in droppings. Furthermore, the persistence of those effects after post-supplementation period is also a dose-dependent phenomenon., Competing Interests: The authors have declared that no competing interests exist.

Background: Reproductive hens are subjected to a restricted diet to limit the decline in fertility associated with change in body mass. However, endocrine and tissue responses to diet restriction need to be documented., Objective: We evaluated the effect of different levels of feed restriction, with or without fish oil supplementation, on metabolic parameters and adipokine levels in plasma and metabolic tissues of reproductive hens., Methods: We designed an in vivo protocol involving 4 groups of hens; RNS: restricted (Rt) unsupplemented, ANS: ad libitum (Ad, receiving an amount of feed 1.7 times greater than animals on the restricted diet) unsupplemented, RS: Rt supplemented, and AS: Ad supplemented. The fish oil supplement was used at 1% of the total diet composition., Results: Hens fed with the Rt diet had a significantly (P < 0.0001) lower growth than Ad hens, while the fish oil supplementation had no effect on these parameters. Furthermore, the bioelectrical impedance analysis (BIA) and the fat ultrasonographic examinations produced similar results to the other methods that required animals to be killed (carcass analysis and weight of adipose tissue). In addition, the Rt diet significantly (P < 0.05) decreased plasma levels of triglycerides, phospholipids, glucose and ADIPOQ, and fish oil supplementation decreased plasma levels of RARRES2. We also showed a positive correlation between insulin values and ADIPOQ or NAMPT or RARRES2 values, and a negative correlation of fat percentage to RARRES2 values. Moreover, the effects of the Rt diet and fish oil supplementation on the mRNA expression depended on the factors tested and the hen age., Conclusions: Rt diet and fish oil supplementation are able to modulate metabolic parameters and the expression of adipokines and their receptors in metabolic tissue.

Background: Polyunsaturated fatty acids (PUFA) are crucial components of egg yolk and particularly prone to oxidative damage, generating losses of nutrients for embryonic development and influencing the quality of eggs for human consumption. The aim of this study was to evaluate whether dietary thymol (a natural antioxidant) is related to changes in quail egg yolk total (T), triglyceride (TG) and phospholipid (PL) fatty acid composition at different stages of embryo development. Thus female Japanese quail (100 days of age) were assigned to one of two dietary treatments (12 individuals each): CON (basal diet) or THY (0.0016 mol thymol day -1 per bird). After 2 weeks of supplementation, eggs were incubated and samples were obtained at 0, 4 and 16 days of embryonic development., Results: In 0 day THY eggs, α-linolenic acid and n-3 PUFA in T and TG, docosahexaenoic acid and PUFA in T and arachidonic acid in TG were increased, while saturated fatty acids (SFA) in T were reduced. From 4 days on, PUFA, n-3 PUFA and SFA from T and TG in THY eggs were found to be similar to those of CON eggs. The changes in PL throughout incubation were similar in both dietary treatments., Conclusion: Thymol would provide the embryo with PUFA for synthesis/deposition in membranes and/or assign to supply energy. Additionally, thymol supplementation would be advisable for the production of healthier table eggs. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

The limited efficiency with which dietary alpha-linolenic acid (ALA) is converted by hens into docosahexaenoic acid (DHA) for egg deposition is not clearly understood. In this study, dietary ALA levels were increased via the inclusion of hempseed (HS) and hempseed oil (HO) in hen diets, with the goal of assessing the effects on the fatty acid (FA) profiles of total lipids and lipid classes in yolk, liver and plasma. Forty-eight hens were individually caged and fed one of six diets containing either HS:10, 20 or 30, HO:4.5 or 9.0 (%, diet) or a control (containing corn oil), providing a range (0.1-1.28 %, diet) of ALA. Fatty acid methyl esters of total lipids and lipid classes, including phosphatidyl choline (PtdCho) and ethanolamine (PtdEtn) in yolk, plasma and liver were then determined. Levels of n-3 FAs in both total lipids and lipid classes increased in all tissues. ALA and eicosapentaenoic acid (EPA) increased linearly, while docosapentaenoic acid and DHA increased quadratically. The FA profiles of yolk closely reflected levels in both plasma and liver. While ALA was highly concentrated in the triacylglycerol, it was low but equally distributed between PtdCho and PtdEtn in all tissues; however, the net accumulation was lower (P < 0.0001) in liver compared to yolk and plasma. Levels of EPA and ALA in yolk-PtdEtn were linearly (P < 0.0001; R (2) = 0.93) associated, and reflected those in liver-PtdEtn (P < 0.0001; R (2) = 0.90). In the liver, a strong inverse correlation (P < 0.0001; r = -0.94) between PL-DHA and ALA-to-EPA ratio in PtdEtn supports theories of low substrate availability, possibly limiting the conversion of ALA into DHA for egg enrichment.

Hempseed products represent potential alternative feed ingredients for poultry. However, their usage is not currently approved due to a lack of data to support their safety and efficacy. In this regard, the current study was conducted to assess the impact of dietary concentration of hempseed (HS) products and duration of their feeding to hens on the polyunsaturated fatty acid (PUFA) composition of egg yolk lipids. In the current study, 48 Lohmann LSL-Classic hens were individually housed in metabolism cages, in a completely randomized design, and provided one of six diets (wheat-barley-soybean-based) containing either HS (10, 20 and 30 %), hempseed oil (HO; 4.5 and 9.0 %) or no hempseed product (control) over 12 weeks. Increasing alpha-linolenic acid (ALA) intake via increasing dietary hempseed product inclusion, significantly (p < 0.0001) increased the n-3 PUFA contents of yolk total lipid. The values of ALA increased by 12-fold (152 ± 3.56 and 156 ± 2.42 mg/yolk) and docosahexaenoic acid (DHA) by twofold to threefold (41.3 ± 1.57 and 43.6 ± 1.61 mg/yolk) over the control, for the highest levels of HS and HO inclusion, respectively. Increasing levels of hemp products in laying hen diets proved effective in manipulating the fatty acid profile of the total lipid, triacylglycerol (TAG) and total phospholipid (PL) fractions of yolks, enhancing the n-3 fatty acids and reducing the n-6/n-3 ratio. The latter benefit was achieved within 4 weeks of feeding hens either HS- or HO-containing diets.

Most CLA chicken feeding trials used cis,trans (c,t) and trans,cis (t,c) CLA isomers to produce CLA-rich eggs, while reports of trans,trans (t,t) CLA enrichment in egg yolks are limited. The CLA yolk fatty acid profile changes and the 10-12 days of feeding needed for maximum CLA are well documented, but there is no information describing CLA accumulation during initial feed administration. In addition, no information on CLA accumulation rates in different hen strains is available. The aim of this study was to determine a mathematical model that described yolk CLA accumulation and depletion in three hen strains by using t,t CLA-rich soybean oil produced by photoisomerization. Diets of 30-week Leghorns, broilers, and jungle fowl were supplemented with 15% CLA-rich soy oil for 16 days, and eggs were collected for 32 days. Yolk fatty acid profiles were measured by GC-FID. CLA accumulation and depletion was modeled by both quadratic and piecewise regression analysis. A strong quadratic model was proposed, but it was not as effective as piecewise regression in describing CLA accumulation and depletion. Broiler hen eggs contained the greatest concentration of CLA at 3.2 mol/100 g egg yolk, then jungle fowl at 2.9 mol CLA, and Leghorns at 2.3 mol CLA. The t,t CLA isomer levels remained at 55% of total yolk CLA during CLA feeding. However, t-10,c-12 (t,c) CLA concentration increased slightly during CLA accumulation and was significantly greater than c-9,t-11 CLA. Jungle fowl had the smallest increase in yolk saturated fat with CLA yolk accumulation.

The desaturation of α-linolenic acid (ALA) to stearidonic acid (SDA) is considered to be rate-limiting for the hepatic conversion of ALA to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in humans, rodents, and chickens. Thus, we hypothesized that feeding laying hens SDA, as a component of the oil derived from the genetic modification of the soybean, would bypass this inefficient metabolic step and result in the enrichment of eggs with EPA and DHA at amounts comparable to that achieved by direct supplementation of hens' diet with these very long-chain (VLC) n-3 polyunsaturated fatty acids (PUFAs). In a 28-d study, laying hens incorporated 0.132 mg, 0.041 mg, or 0.075 mg of VLC n-3 PUFAs into egg yolk for each milligram of ingested dietary ALA derived primarily from conventional soybean oil (CON), dietary ALA derived primarily from flaxseed oil (FLAX), or dietary SDA derived from SDA-enriched soybean oil, respectively. Moreover, the amounts of total yolk VLC n-3 PUFAs in eggs from hens fed the CON (51 mg), FLAX (91 mg), or SDA (125 mg) oils were markedly less than the 305 mg found in eggs from fish oil-fed hens. Unexpectedly, SDA appeared to be more readily incorporated into adipose tissue than into egg yolk. Since egg yolk FAs typically reflect the hens' dietary pattern, these tissue-specific differences suggest the existence of an alternate pathway for the hepatic secretion and transport of SDA in the laying hen.

The xanthophyll β-cryptoxanthin provides vitamin A and has other purported health benefits. Laying hens deposit xanthophyll carotenoids into egg yolk. Hens (n = 8/group) were fed conventional-bred high β-cryptoxanthin biofortified (orange) maize, tangerine peel-fortified white maize, lutein-fortified yellow maize, or white maize for 40 d to investigate yolk color changes using L*a*b* scales, yolk carotenoid enhancement, and hen vitamin A status. Yolks from hens fed orange maize had scores indicating a darker, orange color and mean higher β-cryptoxanthin, zeaxanthin, and β-carotene concentrations (8.43 ± 1.82, 23.1 ± 4.8, 0.16 ± 0.08 nmol/g, respectively) than other treatments (P < 0.0001). Yolk retinol concentrations (mean: 14.4 ± 3.42 nmol/g) were similar among groups and decreased with time (P < 0.0001). Hens fed orange maize had higher liver retinol (0.53 ± 0.20 μmol/g liver) than other groups (P < 0.0001). β-Cryptoxanthin-biofortified eggs could be another choice for consumers, providing enhanced color through a provitamin A carotenoid and supporting eggs' status as a functional food.

To evaluate the effect of flavin-containing monooxygenase 3 (FMO3) genotype and dietary choline supplementation on trimethylamine (TMA) metabolism in HyLine Brown laying hens, a 3 × 2 two-factorial arrangement was employed with FMO3 genotypes (AA, AT, and TT) and dietary choline supplemental levels (370 and 2,960 mg/kg of diet) as main effects. At 46 wk of age, 108 hens of AT genotype and 108 hens of TT genotype were randomly allotted to one of the 2 dietary treatments, and each dietary treatment consisted of 6 replicates with 9 birds each. A total of 24 hens with AA genotype was allotted to one of the 2 dietary treatments that consisted of 6 replicates with 2 hens. Hens were fed the diet with 370 mg/kg of choline supplementation for 1 wk of adaptation followed by a 6-wk trial period. Yolk TMA concentration was increased by dietary supplemental choline at 2,960 mg/kg (P < 0.05), and TT hens showed a higher TMA content in egg yolks than that in AA and AT hens (P < 0.05). Dietary supplementation of choline at 2,960 mg/kg increased the TMA concentration of cecal chyme (P < 0.05) and serum (P < 0.05). Hepatic FMO3 mRNA levels in hens were reduced by higher choline added to the diet (P < 0.05). The TMA and methimazole oxidation rate in AA hens was higher than those in AT and TT hens (P < 0.05). A higher choline diet decreased hepatic FMO3 activity by 33.99% (P < 0.05) and 61.39% (P < 0.05) toward TMA and methimazole, respectively. These results suggest that lower hepatic FMO3 activity caused by the mutation may be responsible for the genotype difference in the TMA metabolism. Exposure to a high dosage of dietary choline increased TMA synthesis in the cecum, suppressed activity of FMO3 in liver, and consequently aggravated the burden of TMA metabolism, especially in TT hens.

Unlabelled: Hempseed (HS) is rich in omega-3 polyunsaturated fatty acids, with approximately 17% of total fatty acids as alpha-linolenic acid. As such, HS and its oil may be used in hen diet formulations to produce eggs enriched in essential fatty acids. Because omega-3 eggs have the potential for unpleasant aromas and flavors, the current study was designed to assess the fatty acid profile and sensory attributes of eggs procured from hens consuming diets containing hempseed oil (HO) or HS. A total of 48 individually caged White Bovan hens received 1 of 6 diets containing 4%, 8%, 12% HO, 10%, 20% HS or 0% hemp (w/w) for 12 wk. Total omega-3 polyunsaturated fatty acid content was highest in the 12% HO group (15.3 mg/g of yolk) compared to the control (2.4 mg/g of yolk). Trained panellists (n= 8) found no significant differences (P≥ 0.05) in aroma or flavor between cooked eggs from different dietary treatments, with the exception of sweet flavor. The 4% HO group yielded the least sweet eggs compared to the 20% HS group, which was highest. For yolk color, L*, a*, and b* values (Mean ± SEM) for control eggs were 61.2 ± 0.10, 1.1 ± 0.05, and 43.0 ± 0.22, respectively. Addition of hemp led to significant (P < 0.001) reductions in L*, and significant increases in a* and b*, with the largest changes observed in the 20% HS treatment (L*= 58.7 ± 0.10; a*= 5.8 ± 0.05; b*= 60.5 ± 0.22). The results show that hemp use in hen diets leads to increased omega-3 polyunsaturated fatty acid content and color intensity of egg yolks, but does not have adverse effects on the sensory profiles of the cooked eggs., Practical Application: This study provides evidence that HS and hempseed oil (HO) can safely be utilized as feed ingredients for laying hens to produce table eggs that are enriched in essential fatty acids. Additionally, the eggs procured from these hens had similar aroma and flavor compared to eggs from hens not fed any hemp. The greater the dietary hemp inclusion, the more pigmented the resulting yolks became in terms of darkness, redness, and yellowness., (© 2012 Institute of Food Technologists®)

Background: This study attempts to compare two possibilities of enhancing the colour of egg yolk. One of them is based on the ecological rearing of laying hens on natural green grass whereas the other uses a feeding dose supplemented with natural pigments in laying hens reared in individual cages. Is it possible to distinguish these two technologies using yolk colour determination in the CIELAB system?, Results: Yolk colour parameters such as L*, a*, and b* in the group of grazed hens are significantly different (α = 0.001) from those observed in hens reared in cages. The yolk colour shows a darker, redder and more yellow colour. The greatest difference was seen in the red colour parameter, a*, that increased more than twice. Visually, this means a shift towards a more orange colour. Compared to grazing in the meadow (ΔE* = 13.257), the addition of artificial pigments in the feed resulted in a more significant increase in the parameter ΔE* (CIE total colour difference), with the greatest value of ΔE* being observed with the use of both pigments (ΔE* = 24.265)., Conclusion: Grazing increases the parameter a* whereas the values of the parameter C*(ab) remain relatively low. The parameter ΔE* is significantly lower in the case of grazing as compared to the supplementation of the feed with pigments. However, colourity parameters cannot be used as a specific standard to identify a particular grazing technology as their values vary during the laying period., (Copyright © 2011 Society of Chemical Industry.)

Resonance Raman spectroscopic measurements are suited to analyze the concentration of carotenoid antioxidants in biological samples. Previously, it has been shown that the carotenoid concentration of nutritional egg yolks has a direct influence on the carotenoid content of human skin in vivo. In the present study, resonance Raman spectroscopy was used to analyze the carotenoid concentration in the yolks of hen eggs, which were housed in battery cages or alternatively on free-range grassland. The egg yolks of hens, which had access to grassland, contained approximately double the amount of carotenoid concentration than the egg yolks of hens housed in battery cages (p < 0.001). The kinetics of the carotenoid concentration in the egg yolks, depending on fodder, housing and weather conditions, were investigated., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Results concerning the contents of retinol in the liver, residual yoke of 25-day embryos and yoke of eggs depending on the level of vitamins A, D3 and E in the diet of geese by grey Obroshin breeds in reproductive period are presented in the paper. It is established, that vitamin D3 reduces the level of retinol deposition in the tissues of embryos and yoke of eggs of geese, and addition of vitamins A and E to a diet of geese raises the level of retinol both in the liver and residual yoke of embryos, and in yokes of geese eggs. Besides the data about changes of fatty-acid spectrum of common lipids and contents of lipid peroxidations products in tissues of the liver and pectoral muscles of 25-day embryos are presented in the paper depending on the level of vitamins A, D3 and E in geese diet during their reproductive period. Introduction of vitamin A--in quantity of 10000 IU, vitamin D3--in quantity of 3000 IU, in the composition of mixed fodder of geese during the reproductive period and vitamin E in quantity 35 IU on 1 kg to mixed fodder optimizes fatty-acid structure of the common lipids and the level of peroxidations lipids products in the liver and pectoral muscles of embryos.

Background: Supplying egg-laying hens with different forage materials may influence egg production and quality. The aim of this study was to examine the short-term effects of standard feed plus 70 g day(-1) per hen of three coloured carrot varieties (orange, yellow and purple) as forage material in comparison with a standard feed control on egg production, egg yolk colour and deposition of carotenoids in the yolk., Results: Carrot supplementation reduced feed intakes significantly, but not on a dry matter basis. Orange carrot treatment significantly reduced egg mass production, whereas yellow and purple carrot treatments did not differ from the control. Egg and yolk weights of all carrot-supplemented treatments were significantly lower than those of the control, but yolk percentages were similar. Yolk redness increased significantly in the order control < yellow < orange < purple. A similar trend was seen for yolk yellowness, but yellow and orange carrots reached the same level. Yolk colour and carotenoid contents correlated positively and significantly. In particular, purple carrot treatment increased the yolk content of lutein (>1.5-fold) and beta-carotene (>100-fold) compared with the control., Conclusion: Supplementing the feed of egg-laying hens with coloured carrots efficiently increased yolk colour parameters and carotenoid contents, which gives opportunities for improved nutritional value of eggs from forage material-supplemented hens.

Carotenoids are partially responsible for the colors of plants and when consumed by humans and animals are deposited into tissues (e.g., skin and egg yolk in laying hens) and may have health benefits. Because carotenoids are more available when consumed from egg yolk sources than vegetables, this research examined the ability of the laying hen to deposit dietary lycopene, a carotenoid that imparts red color in tomatoes, into the egg yolk and to investigate effects on immune function. All birds were housed in commercial cages, had ad libitum access to water, and were fed 100 g/bird per day. Experiment 1 consisted of 4 dietary concentrations of lycopene (0, 65, 257, and 650 mg of lycopene/kg of diet). High-performance liquid chromatography analysis confirmed that dietary lycopene was incorporated into egg yolks. Experiment 2 was a completely randomized design, with 3 concentrations of lycopene (0, 420, and 840 mg of lycopene/kg of diet) and 6 concentrations of alpha-tocopherol (0, 84, 164, 200, 284, and 364 mg of alpha-tocopherol/kg of diet). Egg yolk lycopene (P < 0.05) and vitamin E (P < 0.05) were increased with increasing dietary concentrations, whereas lutein and zeaxanthin concentrations remained constant. Immune responses (inflammatory, cutaneous basophil hypersensitivity, 1 degrees and 2 degrees antibody response) were induced but were not affected by dietary lycopene or vitamin E. These data indicate that lycopene can be incorporated into egg yolks, and at these dietary concentrations, alpha-tocopherol and lycopene may not affect the immune system of the laying hen.

Fatty acid concentrations found in the yolk of green sea turtles reflect differences in the diet of the mothers. All of the 12 fatty acids measured in yolk samples were significantly different between eggs produced from the pellet and wild-type diets. However, the relative pattern of yolk fatty acids in the green turtle mirrored those of other reptiles. Yolk samples contained mostly (63-67%) 14:0. 16:0, 16:1n-7 and 18:1n-9. Yolks from captive animals on pellet diet contained an additional 17.64% of the total yolk lipid as 12:0 and 18:2n-6. Wild yolks contained an extra 11.41% of lipid as 18:0 and 18:1n-7. Selection of fatty acids for the yolk should balance the energetic and anabolic needs of the embryo. Eggs are provisioned based on maternal metabolism of available nutrients and subtle differences between natural foods and those available in captivity could affect the viability of future eggs.

This study was performed to examine an efficient way to use oil by-product which is obtained during the purification process of conjugated linoleic acid (CLA) from safflower oil. The CLA by-product (CBP) was fed to the laying hens to accumulate CLA in the egg yolk. Egg yolk samples from 3 different dietary groups were analyzed: control; CBP, 2%; and CLA-80 (which contained 80% free form of CLA), 2%. Fatty acids from the yolk were analyzed by gas chromatography, and the parameters of egg quality were determined. During the feeding trial, there was little alteration in the egg quality and egg production of the tested groups. The CLA contents in the test group with CBP, which contain CLA as glyceride form, significantly increased in the first week of feeding and had the highest level among the tested groups throughout the feeding trials, whereas the CLA group showed an increase in CLA contents from the third week. Moreover, the contents of total CLA isomers in CLA-80 and CBP oils were decreased by 12.92 and 0.51% after heat treatment in 48 h, and the contents of linoleic acid (LA) isomer in LA-80 (which contained 80% free form of LA) and LA by-product (LBP) oils were decreased by 19.63 and 5.78%, respectively. It was confirmed that a major form of fats in CBP was mainly esterified forms, whereas the fats in CLA-80 and LA-80 were composed of free fatty acids. There was no significant difference in the egg quality and production among the tested groups. It is meaningful that the oil by-product could be utilized as a source for functional foods of animal origin without influencing egg quality and production.

A modifying effect is established of amaranth's corn on lipid composition of pancreas and skeletal muscles of quail - content of cholesterol goes down, the level of triacylglycerols and ethers of cholesterol rises, while the quantity of general lipids and correlation of their separate fractions in egg's yolk did not change substantially.

Under insufficient vitamin content in a diet of laying hens in compliance with lowered vitamins A, E and carotenoids content in an egg yolk acid- and water-soluble chitosan feeding (10 and 20 mg per 1 kg body mass) within 6-9 months did not render appreciable influence on these vitamins egg content. Long-term inclusion of a sorbent in a forage was not reflected in vitamin B2 level in a whole egg, blood serum and tissues of hens. Chitosan intake didn't lead to total lipids and phospholipids concentration in a whole egg. Under 15 per cent decrease of the sum of polyunsaturated fat acids its administration lead to 24 per cent increase of omega-3 polyunsaturated fat acids in the whole egg.

A mathematical model for the kinetics of carry-over of dioxins and dioxin-like PCBs from feed mixed with contaminated oil to eggs has been developed. This model incorporates uptake of the compounds over the gut wall and their subsequent transport by blood, distribution over the body, hepatic metabolism and excretion through egg yolk fat. The model is analysed with respect to the possibility of identifying as yet unknown model parameters by fitting these to the experimental data. The model was fitted to the experimental data on the carry-over from feed to eggs. The calibrated model was applied to calculate the steady-state concentrations in eggs which were compared to European Maximum Residue Levels for dioxins in feed and eggs, showing that these limits do not match. The feed limit of 0.75 ng TEQ/kg should be reduced to about 0.17 ng TEQ/kg in order to guarantee egg levels below the residue limit of 3 pg TEQ/g fat. Experimental results of carry-over from contaminated soil were used to estimate the absorption of dioxin-like compounds from soils as compared to the absorption from feed, resulting in a value around 40 to 60% absorption from soil as compared to around 90% absorption from feed.

Typically, poultry diets contain 1-2 mg I/kg, but higher concentrations are sometimes used to enhance the I content of eggs. In addition to an increased deposition of I in the yolk, other often adverse responses occur, especially at exceptionally high concentrations. Excess I in grower diets can prevent sexual maturation in male and female fowl, and in layer diets will progressively reduce egg production until, by about 2500 mg I/kg diet, ovulation is inhibited and egg production ceases. Most I accumulates in the thyroid gland, and it is likely that the mechanism responsible for these reproductive disorders involves a modification of thyroid hormone activity. Simultaneous with the declining rate of lay, feed intake declines, egg weight and yolk-cholesterol contents decrease and body weight increases. Whereas fertility is unaffected in female breeders, hatch of fertile eggs is reduced, hatch time extended and embryonic mortality and dead-in-shell proportions increased. In contrast, male fertility is decreased because of an increased incidence of dead spermatozoa, although hatchability of eggs from normally fed hens is unaffected. All reproductive variables, together with feed intake and body weight, are normalised within about 7 d of returning to a diet with normal I levels. Excess I suppresses growth in meat-type chickens, but does not affect feed conversion efficiency. There are transient increases in plasma I and cholesterol concentration during excess I intake in all types of bird. The evidence for varying responses to different I sources is equivocal, but the consensus is that source is probably not important.

A total of 135 laying quails (Coturnix coturnix japonica), 9 weeks old, were divided into three dietary treatment groups. Three replicates were assigned to each treatment group consisting of 15 birds per cage. The diet was supplemented with 0, 100 and 200 ppm Yucca schidigera powder and given ad libitum to the quails for a period of 14 weeks. Body weight, egg production, feed consumption and feed efficiency were not different due to dietary treatments among the groups. Increased egg weight was determined in the control group. Yucca powder supplementation decreased serum glucose, cholesterol triglyceride level in laying quails. Serum total protein concentration was not changed by dietary treatments but albumin level was decreased in quails fed 100 ppm yucca powder. Egg yolk cholesterol concentration was not significantly different among the groups but tended to decline (11.5%) as a result of yucca supplementation. Red Blood Cell (RBC) and White Blood Cell (WBC) counts, packed cell volume (PCV), mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) were not affected by supplementation of yucca powder. However, haemoglobin (HB) concentration was slightly increased and mean corpuscular haemoglobin concentration (MCHC) was significantly increased by 200 ppm yucca powder supplementation to the diet.

Egg quality is a phenotype of, and can profoundly influence fitness in, both mother and offspring. However, the physiological mechanisms that underlie this maternal effect are poorly understood. Carotenoids are hypothesized to enhance antioxidant activity and immune function, and are responsible for the pigmentation of egg yolk. The proximate basis and consequences of this maternal investment, however, have not previously been studied in wild birds. In this supplemental feeding study of lesser black-backed gulls, Larus fuscus, carotenoid-fed females are shown to have increased integument pigmentation, higher plasma concentrations of carotenoids and antioxidant activity, and lower plasma concentrations of immunoglobulins (Igs) in comparison with controls. In turn, carotenoid-fed females produced eggs containing high carotenoid but low Ig concentrations (i.e. passive immunity), whereas control females produced eggs containing low carotenoid but high Ig concentrations. Within-clutch patterns of these resources varied over the laying sequence in a similar manner in both carotenoid-fed and control nests. Our results suggest that carotenoids could be one resource responsible for egg quality maternal effects in birds. We discuss the possible implications of carotenoid-mediated effects on phenotype for fitness in mothers and their offspring.

The effects of dietary fat and broiler breeder age on egg and embryo characteristics during incubation were investigated. Breeders were fed diets containing no added fat or 3.0% added poultry fat (PF) for peak energy intakes of 430 and 467 kcal/hen day (pC/d), or 1.5% PF or 3.0% corn oil at 449 pC/d. Feeding of diets was initiated at 22 wk, and eggs were collected for incubation at 27 and 36 wk of age. Percentage incubational egg weight loss was determined between day of set and Days 6, 12, and 18. Percentage wet and dry embryo weights, embryo moisture content, and eggshell weights were determined at 6, 12, and 18 d of incubation. Percentage yolk sac weight and wet and dry liver weights and moisture content were determined on Days 12 and 18. Percentage gall bladder weight was determined on Day 18. There were no observed effects due to breeder diet. However, eggshell weight at Days 6, 12, and 18 was higher in 27-wk-old hens compared with 36-wk-old hens. Conversely, egg weight loss between Day 0 and Days 6, 12, and 18 and yolk sac weight across Days 12 and 18 of incubation were lower in eggs at 27 wk of age compared with 36 wk. At Day 18, dry embryo weight was higher and wet liver weight was lower at 27 wk compared with 36 wk. A slower rate of DM accumulation in embryos at Week 36 compared to Week 27 was associated with increased incubational water loss and decreased embryo moisture content, eggshell percentage, and yolk sac absorption rate. These data demonstrate that changes in eggshell characteristics with broiler breeder age can alone impact yolk uptake, growth, and body composition in subsequent embryos.

1. The effect of a range of supplementations of vitamin A to the laying hen on the concentration of vitamins A, E, ascorbic acid and carotenoids in the maternal liver, the egg yolk and the embryonic liver were investigated. 2. Four groups of 25 Rhode Island Red hens were fed on standard layer-breeder diets with concentrations of supplemented vitamin A ranging from 0 to 120 micrograms/g retinol equivalents from 28 weeks of age. After 3 months, the concentration of vitamin A in the maternal liver was found to be greatly enhanced in proportion to the increasing rates of supplementation with the vitamin. However, the concentration of vitamin E in the maternal liver was markedly reduced by high dietary contents of vitamin A. 3. The concentration of vitamin A in the yolk of the hens' eggs was markedly increased by the dietary supplementation. However, the concentration of both vitamin E and carotenoids in the yolks were significantly reduced by high dietary contents of vitamin A. 4. The concentration of vitamin A in the liver of the embryo and the day old chick was greatly increased by the high concentrations of maternal vitamin A provision. However, the concentration of vitamin E, carotenoids and ascorbic acid in the embryonic/neonatal liver were significantly reduced by high contents of vitamin A in the maternal diet. 5. The susceptibility of the embryonic/neonatal liver to lipid peroxidation was significantly increased as a result of high provisions of maternal vitamin A. 6. It is concluded that excessive provision of vitamin A to the laying hen results in an adverse effect on vitamin E, carotenoids and ascorbic acid in the embryonic/neonatal liver and can compromise the antioxidant status of the progeny.

Feed carotenoids are not inert substances. In the metabolism of animals, they may undergo a large number of transformations. A number of these compounds have vitamin A activity. Those that have high vitamin A activity usually have fairly low pigmenting properties. Generally only monohydroxy- and monoketocarotenoids are converted into vitamin A. Generally plants synthesize optically active carotenoids. The laying hen is not able to transform all carotenoid configurations so that they can be used to increase egg pigmentation. Feed carotenoids occur in natural compounds in about 60 to 90% trans and 10 to 30% cis form. The trans form is a more effective pigment because of the redder hue and greater stability. Either the hen has the ability to convert some of the trans form into the cis form, or this transformation occurs in the egg yolk. The saponification process improves the digestibility of certain xanthophyll preparations. The efficiency of fat absorption in the hen also influences the deposition rate.

Four colostomated hybrid laying hens were fed, for 6 days, a semisynthetic ration containing 15N labelled casein as sole protein source. Within this period, the hens laid 13 eggs which were fractionated into egg yolk, egg white and egg shell. The N content of these egg fractions was established. A TCE soluble and TCE precipitable fraction (TCE=trichloroacetic acid) were obtained from the fractions of egg yolk and egg white. Additionally, an analysis was made of the set of amino acids contained in the crude protein of the egg yolk, egg white and egg membrane (lysine, histidine and arginine only). The excess 15N atom% (15N') was established in the crude protein, in the nitrogen from the TCE soluble and TCE precipitable fractions and in the N from 17 amino acids of the egg yold and egg white. In the egg membrane fraction the 15N' atom% was determined as percentage of the total amount of N and of the amount of N contained in the basic amino acids. Essential differences between the 3 egg fractions were noticed with regard to the process of initial incorporation of labelled N and the intensity of this process after the onset of 15N application. 15N' was detected in the egg shell as early as 4 hrs after administration of the 15N' dose. Heavy nitrogen was found to be contained in the egg white of eggs that were laid on the 2nd day of experiment. The level of 15N' atom% in the egg white increased essentially during the following days of experiment; the 15N'quantities in the egg white were considerably higher than those in the egg yolk. Similar results were obtained for the process of 15N incorporation into the 17 amino acids. It is assumed that differences between the 3 fractions as observed in the level of labelling and in the pattern of 15N' incorporation are accounted for by the different sites and different times of protein synthesis for the different egg proteins.