Yolk Carotenoid Research Articles

Effect of supplementing corn diet for laying hens with vitamin A and trace minerals on carotenoid content and deposition efficiency in egg yolk.

This study investigated the effects of supplementing laying hen's diet with vitamin A (5,000, 10,000 and 20,000 IU/kg) and trace minerals (Zn, Mn, Cu, Fe and Se) in inorganic and organic form on the carotenoid content and deposition efficiency in egg yolk. Hen's diet consisted of two commercial dent corn hybrids (soft- and hard-type), which differed in their carotenoid profile. The feeding trial was conducted with 252 Lohmann Brown hens allocated in 84 cages that were randomly assigned to 12 dietary treatments (2 hybrids × 3 vitamin A levels × 2 trace mineral forms). After depletion, hens were fed diets without added pigment for 7 wk. Deposition efficiency was calculated based on the carotenoid content in yolk and diets, yolk weight, egg production and diet intake. Tested hybrids significantly differed in the content of total and individual carotenoids in egg yolk, with the exception of except β-cryptoxanthin. Lutein was the main carotenoid in the soft-type hybrid and zeaxanthin in the hard-type one. Lower vitamin A levels tended to increase the yolk content of provitamin A carotenoids and the deposition efficiency of all carotenoids for both hybrid types. In addition, the highest content of lutein in egg yolk was found when the soft-type hybrid was supplemented with the lowest vitamin A level. In contrast, trace minerals showed a relatively small effect on carotenoid content and deposition efficiency. However, a significant hybrid × vitamin A × trace mineral interaction existed mainly because the hard-type hybrid had the highest deposition efficiency of all carotenoids except α-cryptoxanthin when diet was supplemented with organic trace minerals and the lowest vitamin A level. In conclusion, supplementing hen's diet with the lowest vitamin A level improved the content of provitamin A carotenoids in egg yolk for both hybrids as well as lutein content for the soft-type hybrid, whereas organic trace minerals improved the deposition efficiency of most carotenoids only for the hard-type hybrid.

Impact of High-Dose Supplemental Paprika Extract Feeding on Egg Storage and Biochemical Parameters in Laying Hens.

This study aimed to evaluate the effects of paprika extract supplementation on egg storage and blood biochemical parameters in 63-week-old Rhode Island Red (RIR) and Silky Fowl (SF) hens. The hens were divided into three groups: a control group with a basal diet and two groups receiving the basal diet with paprika extract. The trial lasted 28 days, with egg quality (yolk color and albumen pH) assessed after storing eggs at 25 °C for 21 days. A total of 144 eggs were used in 42 treatments (two breeds, three diets, and seven storage periods) with three eggs examined each (four eggs were used on day 0 and five eggs on day 21). Additionally, the yolk carotenoid content, yolk color, and pH of eggs stored at 4 °C and 25 °C were compared. Results showed that yolk color fan score (YCFS) decreased with storage, and SF had a higher albumen pH than RIR, with both breeds exhibiting an increase in pH over time. HDL cholesterol (HDL-C) levels and the HDL-C to total cholesterol ratio were significantly influenced by breed, diet, and their interaction. The HDL-C level in SF was affected linearly and quadratically by diet, while no such trend was observed in RIR. The study concluded that paprika extract affects egg quality and blood lipid profiles differently in different breeds, highlighting breed-specific responses to dietary supplementation.

Carotenoid deposition in yolks of laying hens fed with corn diets differing in grain hardness and supplemented with rapeseed oil and emulsifier

This study investigated the effects of supplementing diets consisting of two dent corn hybrids (soft- and hard-type) with different amounts of rapeseed oil (2, 3, and 4%) and with (0.05%) or without emulsifier (Lysoforte Extended, Kemin) on the content and deposition of carotenoids in egg yolk. The feeding trial was conducted with 216 Lohmann Brown laying hens which were by 3 located in 72 cages. The cages were randomly assigned to 12 dietary treatments (2 hybrids × 3 rapeseed oil levels × 2 emulsifier levels), resulting in 6 cages (replicates) per each dietary treatment. After depletion, hens were fed treatment diets without added pigment for 7 wk. After stabilization of the carotenoid profile (lutein, zeaxanthin, α- and β-cryptoxanthin and β-carotene and total carotenoids), eggs were collected once a week until the end of the experiment and deposition efficiency was calculated based on carotenoid content in yolk and diets, yolk weight, egg production and diet intake. Corn hybrid and rapeseed oil affected (P < 0.05) the yolk content and deposition efficiency of most carotenoids. Moreover, a significant (P < 0.05) hybrid × rapeseed oil level interaction for all carotenoids indicated hybrid-specific responses to rapeseed oil supplementation. In the soft-type hybrid, the addition of 3% rapeseed oil enhanced the carotenoid content compared to 2% of rapeseed oil, whereas for the hard-type hybrid, 2 and 3% of rapeseed oil resulted in similar contents. Supplementation of 4% rapeseed oil reduced the content regardless of the hybrid. Emulsifier addition positively affected (P < 0.05) the deposition efficiency of all carotenoids except β-carotene. In conclusion, supplementing corn diets with rapeseed oil and emulsifier affected carotenoid utilization and these responses varied in hybrids differing in grain hardness, which should be considered when using corn as the sole source of carotenoids in hen diets.

Carotenoid content and deposition efficiency in yolks of laying hens fed with dent corn hybrids differing in grain hardness and processing

Yolk carotenoid profile reflects the hen diet when corn grain is the only source of carotenoids, but corn origin and processing may affect carotenoid utilization. In the present study, 2 commercial dent corn hybrids differing in grain hardness (soft- and hard-type) were dried at low (40°C) and high (85°C) temperature and ground through a 5- and 9-mm sieve to investigate their effects on carotenoid bioavailability in laying hens. With 3 hens per cage, 168 Lohmann Brown laying hens were allocated to 8 dietary treatments (2 hybrids × 2 drying temperatures × 2 grinding sieves) in a completely randomized design (8 treatments × 7 cages). The trial lasted 8 wk, during which eggs were collected for analysis every 3 d until carotenoid content stabilized, and then once a week until the end of the experiment. The carotenoid profile of the experimental diets and yolks was analyzed using an HPLC method and deposition efficiency was calculated based on carotenoid contents, yolk weight, egg production and diet intake. The deposition efficiency for lutein, zeaxanthin, α- and β-cryptoxanthin, and β-carotene averaged 27.37, 18.67, 6.29, 3,32, and 0.94%, respectively. As expected, the tested hybrids highly affected the carotenoid content in egg yolk due to their differences in carotenoid profile. Interestingly, hard- and soft-type hybrids differed in the deposition efficiency for all individual carotenoids but not for the total carotenoids. High grain drying temperature tended to increase the bioavailability of lutein and zeaxanthin in both hybrids. For the hard-type hybrid, the content of β-carotene in egg yolk was higher when grains were dried at a high temperature, while the opposite response was found in the soft-type hybrid. The effect of grinding sieve size was important for the zeaxanthin bioavailability in the soft-type hybrid only. In conclusion, our findings showed that corn hybrid had a primary influence on the carotenoid content in the yolks of laying hens, but grain processing may change the bioavailability of carotenoids.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ КАРОТИНСОДЕРЖАЩИХ ПРЕПАРАТОВ В РАЦИОНАХ КУР-НЕСУШЕК

Deficiency of carotene and vitamin A leads to various diseases of young birds, a sharp decrease in the productivity of adult birds. As you know, beta-carotene, unlike vitamin A, does not have toxic properties, it protects the liver from hepatotropic poisons and gives poultry products a good marketable appearance. This paper presents the results of studies on the influence of carotene- containing preparations caroflavin and carophyllin on the body of laying hens and the marketable quality of eggs. We evaluated the productivity of laying hens. After the use of caroflavin and carophyllin, the egg production of hens increased by 2,9% and 3,7%, the amount of carotenoids in the egg yolk increased by 25,2 and 33%, vitamin E – by 23,5 and 64,7%, and vitamin A – by 34,8 and 52,2% compared to the control.

Influence of organic and cage housing system on egg quality in laying hens

Abstract Most of the eggs for consumption are produced in a conventional housing system although the demand for organic eggs is increasing because consumers assume better nutritional characteristics. This study was conducted to compare the quality of organic eggs and enriched cage eggs. A total of 409 organic eggs and 385 eggs from hens housed in enriched cages were directly collected from 15 different farms, located in Spain and were analyzed within 4 days after laying. The differences in quality by removing the time bias that can be caused by marketing time were thus determined. All the hens were of three different lines, 47–50 weeks old and consumed commercial feed with the same nutritional composition. The quality traits evaluated were egg weight (EW g), egg shape index (SI), shell thickness (ST), shell percentage (SP), Haugh units (HU), dense albumen percentage (DAP), total albumen percentage (TAP), yolk color (YC), yolk percentage (YP), Roche scale (RS), moisture (M), ash content (AC), total protein (TP), total yolk carotenoids (TYC), total fat (TF), saturated fatty acids (SFA), monounsaturated fatty acids (MFA), and polyunsaturated fatty acids (PFA). Estimates of differences were obtained by generalized least squares using housing system, genetic line and their interaction as factors. Significant differences were observed for EW (65.3 vs 62.9), SI (77.60 vs 76.10), HU (83.60 vs 81.80), TAP (66.5 vs 64.17), YC (3.11 vs 1.89), RS (11.79 vs 9.48), TP (9.99 vs 8.55), TYC (4.188 vs 2.650), SFA (32.20 vs 30.00) and MFA (53.40 vs 44.20) in favor of the enriched cage system. In the organic system, the quality parameters that had higher and significant values were ST (0.34 vs 0.32), SP (10.52 vs 9.41), YP (25.20 vs 24.30), AC (1.12 vs 0.93) and PFA (26.00 vs 14.00). Significant interactions between the housing system and the hen line followed the same pattern observed for fixed effects. Organic eggs were lighter, less rounded with better shell quality and therefore showed lower Haugh unit values and a lower albumen percentage. Total protein, total fat, and lipid profile were within the usual average values for commercial eggs, although the proportion of polyunsaturated fatty acids, which are beneficial for consumers, was higher in organic eggs.

Egg laying performance and egg quality with Paracoccus carotinifaciens supplementation containing high astaxanthin levels

ABSTRACT 1. This study assessed 1) the effects of Paracoccus carotinifaciens supplementation containing high astaxanthin levels on egg production performance and quality, 2) dynamics of carotenoids levels in the egg yolk and 3) taste of astaxanthin-rich egg yolk. 2. Laying hens were fed diets containing different levels of P. carotinifaciens-derived astaxanthin (ASX; 0, 2, 4, 8, or 16 ppm) for 28 d (experiment 1) or a diet containing 16 ppm astaxanthin for 28 d followed by a 0 ppm astaxanthin diet for 28 days (experiment 2). 3. Production performance, egg quality and egg yolk carotenoid levels were examined in experiment 1 (Ex1) and the dynamics of egg yolk carotenoid levels and egg yolk taste in experiment 2 (Ex2). 4. ASX supplementation did not affect production performance or egg quality. ASX levels in the egg yolk became saturated after seven days of 16 ppm supplementation and decreased to less than one-tenth of the saturated levels seven days after supplementation cessation. Supplementation with 16 ppm ASX for 28 d did not affect egg yolk taste. 5. Supplementation resulted in the production of ASX-rich eggs for a brief period without affecting production performance, egg quality or taste. Understanding the time taken for the incorporation of ASX into egg yolks is beneficial for value-added egg production and may help in minimising supplementation costs.

Influence of designer diet and holy basil (Ocimum sanctum) leaves on yolk colour, yolk carotenoid, and immunity status of layers

A biological experiment of six weeks duration, followed by several laboratory investigations was carried out to study the effect of designer layer mash (DLM) containing full fat flaxseed, oil rich sardine fish, holy basil leaf meal (BLM), vitamin E and organic selenium (Sel-plex), on yolk colour, carotenoid and immune status of layers. Both designer diet and BLM had significantly improved the yolk colour and pigment levels. They also exhibited a synergistic effect. The DLM had significantly increased the vitamin E and selenium levels in the egg; but BLM had no such effect. The immune status of the layers, expressed as Immunoglobulin IgY and HI titre, indicated that both designer diet as well as the BLM had significantly improved the IgY levels and HI titre.

Commercial Corn Hybrids as a Single Source of Dietary Carotenoids: Effect on Egg Yolk Carotenoid Profile and Pigmentation

Commercial high-yielding corn hybrids have not been evaluated for their ability to pigment egg yolk. Therefore, the objective of this research was to investigate the effects of commercial hybrids with different carotenoid profiles as the only source of pigments in the diets of hens on yolk color and carotenoid content, as well as the carotenoid deposition efficiency into the yolk. Treatment diets, differing only in one of five corn hybrids, were offered in a completely randomized design in six cages per treatment, each with three hens. Treatment diets and yolks differed in carotenoid profile (contents of lutein, zeaxanthin, β-cryptoxanthin and β-carotene, p &lt; 0.001), with total carotenoid contents ranging from 17.13–13.45 µg/g in diet and 25.99–21.97 µg/g in yolk. The treatments differed (p &lt; 0.001) in yolk color, which was determined by yolk color fan (10.8–9.83) and CIE Lab (redness; range 12.47–10.05). The highest yolk color intensity was achieved by a diet with the highest content of zeaxanthin, β-cryptoxanthin and β-carotene. The deposition efficiency of lutein and zeaxanthin (25.52 and 26.05%, respectively) was higher than that of β-cryptoxanthin and β-carotene (8.30 and 5.65%, respectively), and the deposition efficiency of all carotenoids decreased with increasing dietary content. Commercial corn hybrids provided adequate yolk color and could be the only source of carotenoids in the diets of hens, which could reduce the cost of egg production and increase farmers’ income.

Applied Research Note: “The impact of orange corn in laying hen diets on yolk pigmentation and xanthophyll carotenoid concentrations on a percent inclusion rate basis”

Consumers associate nutritional quality and potential health benefits with yolks showing deeper colors produced by healthy layers fed a well-balanced, nutrient-rich diet. However, cereals and oilseed meals generally used in poultry feed do not provide sufficient carotenoids to achieve deeper yolk colors, thus carotenoid additives may be supplemented. High carotenoid corn genotypes have been developed, and when included in poultry diets increase carotenoid concentrations in yolks. Seven different diets were fed to 210 Novogen White laying hens over 21 d. Each diet had 5 replicates of 6 hens housed in conventional cages. The only difference in diet treatments was percent inclusion rate of orange corn or inclusion of a carotenoid additive (Oro Glo). Yolk color was assessed by colorimeter and DSM YolkFan. Yolk carotenoid concentrations were determined by high performance liquid chromatography. Yolks from hens fed diets with a 100% orange corn inclusion rate had the highest YolkFan scores and total xanthophyll levels at the end of the study. Orange corn inclusion rate showed a linear relationship with colorimeter a* values (r = 0.96) and YolkFan scores (r = 0.90) for egg yolks. Orange corn inclusion of 50 and 75% produced yolks with a* axis color value equivalent to that found in yolks from hens fed 100% yellow corn plus 35 g/kg of Oro Glo. Data indicates that orange corn can be a suitable replacement for carotenoid additives. A 50 to 75% orange corn inclusion could be sufficient to achieve yolk colors similar to diets that involve supplementation with a carotenoid additive.

Enrichment of chicken table eggs with lycopene and astaxanthin

Ensuring an attractive commercial appearance of egg yolks involves the introduction to the feed of laying hens of the dyes of various origins. Recently, egg producers have preferred natural dyes, which include carotenoids: lycopene and astaxanthin, which can be deposited in chicken egg yolks. The aim of this study was to determine the quality of egg yolks, colour intensity and carotenoid composition of yolks when oil extracts of lycopene (20, 40 and 60 mg/kg feed) or astaxanthin (10, 20 and 30 mg/kg feed) are included in the chickens’ diet. 45 High Line W36 chickens at the age of 24 weeks were used for the experiment. Feeding laying hens with supplements of lycopene oil extracts at doses of 30, 40 and 60 mg/kg and astaxanthin at doses of 10, 20 and 30 mg/kg of feed for 30 days in increasing concentrations did not affect egg weight, albumen height, Haugh unit, strength and the thickness of the shell. The addition of lycopene to the diet of chickens at doses of 20 mg/kg of feed increased the content of lycopene, unidentified carotenoids and the total content of carotenoids in the yolks, but did not change the intensity of their colour. Increasing the dose of lycopene in the diet of chickens to 40 and 60 mg/kg of feed increased the content of lycopene in yolks and the intensity of their colour to 7.4 and 8.0 points against 5.6–6.1 points in the control, but did not affect the content of β-carotene and total carotenoids in the yolks. The addition of astaxanthin oil extract at doses of 10, 20 and 30 mg/kg of feed increased the content of astaxanthin, β-carotene and total carotenoids in chicken egg yolks and increased the intensity of their colour to 12.8, 14.8 and 14.4 points on a 16-point colour scale YolkFanTM. To obtain chicken table eggs with a given colour of the yolks, it is advisable to use the addition of astaxanthin oil extract in doses from 10 to 20 mg/kg of feed for 30 days. The results of the research can be used to develop a technology for the production of functional table eggs enriched with carotenoids of natural origin with an attractive colour for consumers.

ENVIRONMENTAL SAFETY OF FLOOR SANITIZER USE WHEN GROWING POULTRY OF MEAT TYPE

We used “Khotimsky” mineral additive as a sanitary means in the bedding material of laying hens of the cross “Ross-308” parent flock which led to a decrease in the microbial contamination of the poultry house and, consequently, to an increase in the total egg production – by 1.6%; hatching egg yield – by 1.6%; yolk carotenoids – by 3.0% and vitamin A – by 1.5%.

Effects of a probiotic containing Bacillus subtilis on the gut microflora, yolk quality and blood lipid concentrations of laying Pharaon quails

The current literature is not comprehensive concerning the influence of Bacillus subtilis on lipid metabolism, egg chemical characteristics, and intestinal microbiota of Japanese quail. The aim of this study was to evaluate the effects of a Bacillus subtilis strain on yolk quality, gut bacterial populations, and total cholesterol and triglyceride concentrations in the plasma of organically farmed Pharaon quail layers. Forty-five-day-old female quails were randomly distributed into four groups of 10 birds each: a no-treatment control group and three test groups receiving powder of Bacillus subtilis DSM 32424 at a minimum rate of 1 × 106 colony forming units per gram, dissolved in drinking water at doses of 50, 75 and 100 mg per kg body weight, daily during 30 days. The use of the probiotic at doses of 50 and 100 mg resulted in significantly reduced faecal staphylococci count on day 30 (P&amp;lt;0.05), while no significant changes were detected in lactobacilli or coliform bacteria. This study gives the first evidence of the influence of Bacillus subtilis on acid value and carotenoid levels in egg yolks laid by quails. Carotenoids were significantly elevated in the 75 mg group on day 30 (P&amp;lt;0.05), but significantly decreased in the 50 and 100 mg groups (P&amp;lt;0.05). Acidity, triglyceride and total cholesterol concentrations in quail serum were not affected significantly by the treatment throughout the study, though their values were reduced. The inclusion of Bacillus subtilis DSM 32424 in drinking water for laying Pharaon quails inhibited faecal staphylococci proliferation and enhanced yolk carotenoid content. Therefore, it can be proposed that including this probiotic in laying quail diets may have beneficial outcomes for both layers and the second generation.

Possibility of Using Astaxanthin-Rich Dried Cell Powder from Paracoccus carotinifaciens to Improve Egg Yolk Pigmentation of Laying Hens

The study investigated egg quality aspects such as astaxanthin concentration, E/Z-isomer ratio, and yolk color in laying hens fed with astaxanthin-containing diets. Dried Paracoccus carotinifaciens cell powder (Panaferd-AX) and fine cell powder (Panaferd-P) were used as sources of astaxanthin, with average particle diameters of approximately 100 μm and 10 μm, respectively. Paracoccus carotinifaciens contains valuable rare carotenoids such as adonirubin and adonixanthin, and thus the concentrations of these carotenoids in egg yolk were also evaluated. The E/Z-isomer ratios of the egg yolk carotenoids were determined by normal-phase high-performance liquid chromatography (HPLC) with an improved solvent system. Feeding diets containing P. carotinifaciens resulted in increased concentrations of astaxanthin, adonirubin, and adonixanthin in egg yolk, as well as a marked increase in the yolk color fan score; values associated with the Panaferd-P-containing diet were higher than those associated with the Panaferd-AX-containing diet. For example, the astaxanthin concentration in egg yolks of hens fed with the Panaferd-AX- and Panaferd-P-containing diets for 21 days were 1.21 μg/g and 1.85 μg/g, respectively. This indicates that the pulverization treatment of the P. carotinifaciens powder increased the efficiency of carotenoid accumulation in the egg yolk. Moreover, more than 95% of astaxanthin in P. carotinifaciens was present as the all-E-isomer. However, approximately 25% of astaxanthin in egg yolk was present as the Z-isomers. In recent years, astaxanthin Z-isomers have attracted substantial attention as they exhibit a greater bioavailability and bioactivity than the all-E-isomer. These data are important not only for understanding egg yolk pigmentation but also for improving the nutritional value of hens’ egg yolk through the addition of P. carotinifaciens to their diet.

Dietary carotenoid supplementation facilitates egg laying in a wild passerine.

During egg laying, females face a trade‐off between self‐maintenance and investment into current reproduction, since providing eggs with resources is energetically demanding, in particular if females lay one egg per day. However, the costs of egg laying not only relate to energetic requirements, but also depend on the availability of specific resources that are vital for egg production and embryonic development. One of these compounds are carotenoids, pigments with immuno‐stimulatory properties, which are crucial during embryonic development. In this study, we explore how carotenoid availability alleviates this trade‐off and facilitates egg laying in a small bird species, the blue tit (Cyanistes caeruleus). Blue tits have among the largest clutch size of all European passerines and they usually lay one egg per day, although laying interruptions are frequent. We performed a lutein supplementation experiment and measured potential consequences for egg laying capacity and egg quality. We found that lutein‐supplemented females had less laying interruptions and thus completed their clutch faster than control females. No effects of treatment were found on the onset of egg laying or clutch size. Experimentally enhanced carotenoid availability did not elevate yolk carotenoid levels or egg mass, but negatively affected eggshell thickness. Our results provide hence evidence on the limiting role of carotenoids during egg laying. However, the benefits of laying faster following lutein supplementation were counterbalanced by a lower accumulation of calcium in the eggshell. Thus, even though single components may constrain egg laying, it is the combined availability of a range of different resources which ultimately determines egg quality and thus embryonic development.

Production performance, egg quality, and small intestine histomorphology of the laying hens supplemented with phytogenic feed additive

Summary An experiment was conducted to determine the effect of a phytogenic compound (Alquernat Nebsui L [ANL]) applied through drinking water on hen day egg production (HDEP), egg quality, and small intestine histomorphology of Hy-Line W-36 laying hens from 65 to 73 wk of age. A total of 90 hens were randomly allocated into 2 treatment groups with 15 replicate cages, and each cage containing 3 hens. Hens were housed in an A-frame conventional cage and followed the light regime of 16L:8D period. The 2 treatments consisted of either without or with ANL provided via drinking water (0.5 mL/L) as control (CON) and ANL group. Hen day egg production, feed intake (FI), feed conversion ratio (FCR), and egg quality were measured weekly. Supplementation of ANL increased HDEP and decreased FI and FCR in the treated group. The internal quality of eggs Haugh unit (HU), total yolk carotenoids (TYC), and yolk color score (YCS) were significantly increased in the ANL group compared with the CON group. No significant differences were observed in the measured exterior quality of eggs among the 2 treatments. Alquernat Nebsui L did not affect the histomorphology of duodenum, jejunum, and ileum except for the villus width of the duodenum, which was higher in the ANL group than the CON group. There was no significant difference in either absolute or relative intestinal weight in the ANL or CON group. It can be concluded that the addition of ANL in drinking water may have beneficial effects on egg production, FI, FCR, HU, TYC, and YCS.

The use of Golden snail (Pomacea canaliculata) egg as source of carotenoid for improvement of Arabic Chicken egg quality

Consumers awareness of the usage of natural product is increasing but exploration of natural carotenoid originated from animal was conducted into a lesser extent. The objective of this study was to examine the use of Golden snail egg powder (GESP) for improvement of quality of Arabic chicken egg. Thirty six Arabic chicken (silver and golden chicken, 22 weeks of age, 1,123.9 ± 155.1 g initial body weight) were assigned in completely randomized design (CRD), consisting of 4 dietary treatments (R0 = control 0%; R1 = 4%; R2 = 8%; and R3 = 12% level of GESP) and 3 replications. Data were analysed using one way ANOVA with homogeneity and normality tested in advance. After one month of experiment, data showed that up to 12%, yolk carotenoid and yolk score significantly increased in line with dietary GESP level. However Haugh unit and yolk indices were not affected by GESP. This result indicates that Golden snail egg can be used as carotenoid for improvement of chicken egg quality.

Non‐analytical methods for the estimation of total yolk carotenoids in passerine eggs

Carotenoids are essential antioxidant micronutrients. Oviparous species acquire carotenoids from their food and deposit them in the egg yolk, where they support embryonic development. The total carotenoid concentration in the egg yolk is typically measured analytically, which requires time, equipment and expertise, and can limit the sample available for other measurements, at least in species laying small eggs. Here we evaluate whether yolk colour can be used as a reliable alternative measure for total yolk carotenoid concentration. We compare two non‐analytical methods, digital photography and visual colour scoring, using eggs from a wild population of Blue Tits Cyanistes caeruleus. Yolk hue estimated from digital photographs correlated more strongly with total yolk carotenoid concentration measured by high‐performance liquid chromatography (HPLC) than did the visually assessed colour score based on a Yolk Colour Fan. Previous results based on HPLC measurements of total carotenoid concentration could be reproduced using yolk hue measurements. The results suggest that measuring yolk hue is a suitable proxy for assessing natural variation in total yolk carotenoid concentration in eggs of free‐living birds.

Poultry diets containing (keto)carotenoid-enriched maize improve egg yolk color and maintain quality

The raw materials used in poultry feed do not provide sufficient carotenoids to achieve the yolk pigmentation demanded by consumers, so color additives are included usually in the form of carotenoid-rich dried plant extracts. We fed thirty-two laying hens (ISA Brown) on diets supplemented with two genetically engineered maize lines (enriched in carotenoids or ketocarotenoids) to assess egg productivity and quality traits. Four different maize-supplemented diets were compared based on two genetically engineered maize lines (Ph3 and BKT), the white near isogenic wild-type line (M37W) and a commercial feed based on standard commercial (SC) yellow maize. Line M37W-Ph3 (Ph3) accumulates high levels of β-carotene, zeaxanthin and lutein, whereas line NSL76*BKT (BKT) is rich in astaxanthin and other ketocarotenoids. There were no significant differences among the diet groups in terms of egg weight, breaking strength, albumen height, Haugh units, or shell thickness, but there were significant differences in DSM scale values for yolk pigmentation (P < 0.001) that were higher in the Ph3 (10.08) and BKT (11.38) groups than the SC (4.22) and M37W (≤1) groups. At the end of the trial, the total yolk carotenoid content was highest in the Ph3 diet group, followed by BKT, SC and M37W diet groups (56.5, 26.18, 11.54 and 1.81 μg/g freeze-dried yolk, respectively). The Ph3 yolks were enriched in β-carotene and β-cryptoxanthin (pro-vitamin A carotenoids) whereas the BKT yolks accumulated astaxanthin and other ketocarotenoids. The diets had no detrimental effects on the health of the hens. We conclude that (keto)carotenoid-enriched maize enhances the (keto)carotenoid content and color of yolks and can replace the color additives used routinely in poultry feed formulations.

Effect of dietary fat on the content of vitamins and carotenoids in egg yolks

Abstract This study evaluated the effects of fat source in the diet on the content of vitamins E and A, and carotenoids in egg yolks. Hisex Brown hens aged 49–56 weeks were fed on diets that differed in the content of crude fat (a diet without fat and diets supplemented with rapeseed or palm oil at 40Â g/kg). Diets of all hens contained 3% dehydrated alfalfa (a source of carotenoids). Measurement of vitamin and carotenoid content in yolks was carried out by HPLC methods. Supplements of fat increased the α-tocopherol content in egg yolks by 80.1% (rapeseed oil) and 72.1% (palm oil), respectively. The increase of lutein, zeaxanthin and retinol in yolks of hens fed dehydrated alfalfa and oils was less pronounced (varied from 13.4% to 26.5%). Effects of dietary fat supplementation on deposition of lipophilic vitamins and carotenoids were small or statistically non-significant. The saturation of diets with fat increased the hen-day egg production and decreased the feed intake. It can be concluded that dietary inclusion of fat increased the deposition of α-tocopherol, retinol and carotenoids in eggs of hens fed a diet containing dehydrated alfalfa.