Yolk Content Research Articles

The Use of Different Fat Sources on Performance, Egg Quality and Egg Yolk Fatty Acids Content in Laying Quails

In this study, the performance, egg quality, egg yolk colour and fatty acids profile of quails fed on diets containing different fat sources were determined. During 8 weeks trial, a total of 75, 10-weeks-old laying quails were used. Three diets were formulated to contain soybean oil (SBO), sunflower oil (SFO) and hempseed oil (HSO), respectively. The performance parameters were not significantly influenced by the dietary different oil sources. Eggshell ratio, eggshell thickness, eggshell breaking strength, egg shape index, egg yolk index, albumen index and egg yolk colour values (except a*) were not influenced by the different dietary oil sources. The a* value was significantly affected and the highest a* value was the HSO of group. The different oil sources supplementation to the diets was effective on fatty acid composition of the egg yolk. The highest value in terms of α-linolenic acid, total polyunsaturated fatty acids and total n-3 fatty acids were found in the diet fed group with HSO added. As a result; supplementation of different sources of oil to quail diets without negatively affecting performance and egg quality can be used to change the egg yolk fatty acid composition. Hempseed oil may increase the amount of total polyunsaturated fatty acids and total n-3 fatty acid content of egg yolk.

Valorization of postextraction residues—analysis of the influence of new feed additives with micronutrients on eggs quality parameters

This paper presents attempts to enrich hens eggs with ions of copper, manganese, and zinc through the use of new feed additives (19 mg Cu2+; 124 mg Mn2+ and 85 mg Zn2+) such as biomass of alfalfa and goldenrod after extraction with supercritical carbon dioxide enriched with microelements via biosorption. Mechanical parameters of eggs (shell thickness and strength, Haugh unite), hen's laying performance, microelements content in albumen and yolk were examined and the transfer factor from feed to eggs was determined. The highest transfer of microelements content in albumen occurred in the group of hens fed with enriched goldenrod in a 100% dose (daily dose of microelements from biomass; Cu2+ 106%; Mn2+ 104%; Zn2+ 104% more in comparison to the inorganic salt group), while the highest yolk enrichment with microelements manifested itself for hens fed with enriched goldenrod in a 50% dose (daily dose of microelements from biomass; Cu2+ 32%; Zn2+ 22% more in comparison to the inorganic salt group). These groups also had the highest total microelements concentration. Mechanical properties of eggs varied insignificantly during the trial. Production parameters did not differ statistically among all experimental group. Eggs produced with need additives had better organoleptic parameters than fed with conventional premixes, which is why they were preferred by the respondents. The presented technology allows obtaining low-cost feed materials characterized by high bioavailability of components. The produced feed additives can serve as potential material for biofortification of eggs with nutrients.

Supplemental dietary oils rich in oleic acid or linoleic acid attenuate egg yolk and tissue n-3 polyunsaturated fatty acid contents in laying hens co-fed oils enriched in either stearidonic acid or α-linolenic acid

We previously reported that when laying hens were fed diets supplemented with oils enriched in α-linolenic acid (ALA) and oleic acid (OA), the deposition of n-3 PUFA in egg yolk was attenuated as compared to feeding hens a diet supplemented with the ALA-rich oil alone. The present work extends those findings to another n-3 PUFA-rich oil (stearidonic acid [SDA]-enriched soybean oil) and two other high-OA oils, suggesting that the effect is not plant oil-specific. Feeding hens a supplemental linoleic acid (LA)-rich oil plus an oil rich in either SDA or ALA also attenuated egg yolk ALA and SDA contents (Experiment 1), or egg yolk and liver ALA contents (Experiment 2), respectively, as compared to feeding the SDA- or ALA-rich oils alone. Future work should focus on the lack of neutrality of OA and LA in relation to n-3 PUFA nutrition.

Effect of advanced chelate compounds-based mineral supplement in laying hen diet on the performance, egg quality, yolk mineral content, fatty acid composition, and oxidative status

The study aimed to determine the efficiency of advanced chelate compounds-based trace minerals (OTM) in laying hens. Laying hens (240, 32 weeks old) were assigned to one of the following five groups: NOTM (no added trace minerals), CONTM (standard mineral salts), and three experimental groups in which chelates were used to replace 33, 66, and 100% of mineral salts (OTM33, OTM66, and OTM100, respectively). Each treatment had six replicates with eight hens per replicate. After 18 weeks, performance and physicochemical properties of eggs in all experimental groups was better than those in the NOTM group. Among the treatments, OTM66 and OTM100 produced the best results in terms of laying performance, yolk PUFA/SFA ratio, Zn and Se contents, and malondialdehyde concentration in both serum and yolk. In conclusion, up to 66% OTM supplementation was beneficial for performance, lipid and mineral composition of yolk, and oxidative status.

Short communication: Effects of breeder age and pre-placement feed on IgY concentration in egg yolk and chick serum.

Breeder age and pre-placement feed are factors that can affect broiler performance during grow out. This study evaluated the effects of breeder age (29 and 55weeks old) on IgY transference to egg yolk in addition to the effects of breeder age (29 and 55weeks old) and pre-placement feed (with or without), in a factorial arrangement, on IgY concentration in chick serum. Forty-eight eggs were collected from a breeder flock and considered the experimental units. Eighteen chicks from each breeder age were randomly selected to determine IgY at pulling. After 48h of placement, old breeders had greater egg weight and yolk weight (p≤0.05) than the young ones. Breeder age (p>0.05) had no effect on IgY concentration of egg yolk. Breeder age (p>0.05) had no effect on IgY concentration of chick serum at pulling. There was no interaction (p>0.05) between breeder age and pre-placement feed for IgY concentration of chick serum at housing. There was also no effect of breeder age or pre-placement feed during placement time (48h) on IgY concentration of chick serum at housing (p>0.05). In conclusion, 48h of fasting had no effect on IgY concentration in chick serum despite breeder age. It appears that the immunoglobulins from the residual yolk sac are not used as a protein source during the period between hatching and housing.

LAYING PERFORMANCE, HEALTH STATUS and SOME PHYSIOLOGICAL TRAITS of MANDURAH LAYING CHICKENS AFFECTED BY THE ADDITION OF DIFFERENT LEVELS of ANISE AND CARAWAY SEED POWDER

This study was conducted to evaluate the effects of varying levels of Anise and Caraway seeds powder on laying performance, some blood constituents, egg quality traits, yolk cholesterol content, immunity response and total count aerobic bacteria of Mandurah laying chicken. For this purpose, a total number of 140 Mandurah laying chickensat 26 weeks of age were used in this experiment having a completely randomized design, with 7 equal treatment groups, which replicated 4 times with 5 hens per replicate. Each bird was housed in individual wire cage measuring (50 × 50 × 45Cm2), where each bird in each cage allowing 510 Cm2 space/hen). A basal control diet was formulated and supplemented with 0.1, 0.2 and 0.3 % Anise and 0.1, 0.2 and 0.3 % Caraway seeds in powder form. Birds were fed on isocaloric (2751 Kcal ME /Kg) and isonitrogenous (16.14% CP) diets. Results showed that laying performance significantly (P<0.05) improved when inclusion Anise and Caraway seeds powder compared with the control group. However, it was clearly observed that plasma lipids were significantly reduced (P <0.05) by supplementing diets with different levels of anise and caraway seeds. In the same trend, the addition of Anise and Caraway seeds powder led to a clear and significant decrease in egg yolk and blood cholesterol compared with the control group (P<0.05). However, Anise and Caraway seed powder incorporation caused positive effects on the parameters related to immune response and overall total antioxidant capacity (TAC) compared with the control group. While, total count aerobic bacteria significantly (P < 0.05) decreased for birds fed diets inclusion Anise and Caraway seeds powder as compared with the control group. Conclusively, Anise and Caraway seeds powder can be included in the diet of laying hens as a safe and effective feed additive to improve laying performance and reduce total blood lipids and thus reduce cholesterol content in egg yolk.

Effect of dietary pumpkin (Cucurbita moschata) seed meal on layer performance and egg quality characteristics.

ObjectiveThe objective of this study was to investigate the effect of dietary pumpkin (Cucurbita moschata) seed meal (PSM) on laying hens’ performance, quality, fatty acids, cholesterol, antioxidant compounds and shelf life of eggs.MethodsEighty Tetra SL laying hens, 50-week-old, were randomly divided into two equal groups, having 10 replicates with 4 birds in each. The control (CON) treatment was fed with basal diet, while experimental treatment was fed a diet with 9% PSM, for a 6 week period.ResultsDietary PSM significantly decreased average daily feed intake (p<0.05), with no significant effect on other performance parameters. The PSM, enriched the eggs with polyunsaturated fatty acids, especially α linolenic acid (0.33 vs 0.21 g/100 g) and linoleic acid (20.65 vs 18.37 g/100 g), whereas it reduced the amount of arachidonic acid with 3.91% and n−6/n−3 ratio in PSM eggs compared with CON. The inclusion of 9% PSM significantly (p<0.05) diminished the cholesterol concentration in yolk with 11.31% and in egg with 10.38%, in respect to the CON samples. The significantly (p<0.05) higher concentration of polyphenols and antioxidant compounds, determined in PSM eggs, proved to be effective on shelf life of eggs preserved at refrigerator (5°C) and room temperature (21°C) for 28 days, by delaying the lipid oxidation and protein denaturation. This effect was reflected in significantly (p<0.05) higher Haugh unit in eggs stored 28 days at 21°C and lower albumen pH values for the overall storage time, both at 5°C and 21°C, proving the antioxidant effect of pumpkin.ConclusionDietary PSM supplementation was significantly effective on average daily feed intake and egg quality by increasing some fatty acids while lowering the cholesterol concentration. Also, PSM proved to be effective improving shelf life of eggs for 28 days storage time.

Comparative Lipidomics of Chick Yolk Sac during the Embryogenesis Provides Insight into Understanding the Development-Related Lipid Supply.

Yolk sac (YS, include the yolk content) at different chick embryogenesis stages possesses varying lipid distributions, which are nutrition-influencing factors for the health of an early embryo and a later adult. YS lipids can substantially influence embryogenesis metabolism, but a comprehensive understanding of lipid's influence remains unknown. Herein, the effects of embryogenesis on lipid profiling of chick YS were investigated by UHPLC-MS/MS-based lipidomics. A total of 2231 lipid species across 57 subclasses were identified in the YS, and 1011 lipids were significantly different (P < 0.05) at the incubation days of 0, 7, 13, and 18. Specifically, phosphocholine and phosphatidylglycerol in late-stage embryogenesis potentially assist with prehatching gas exchange and infection resistance in the environment after lung respiration. In addition, the accumulated lysophosphatidylcholine at day 18 may induce apoptosis and disturb the membrane structure of YS to enable better absorption by the embryo abdomen. The decreased cardiolipin in late embryogenesis may be due to transportation to the embryo and integration into the mitochondrial membrane to accelerate energy metabolism for the rapidly developing embryo after day 13. Therefore, this study demonstrated the lipid profile alteration of the developing YS, providing theoretical guidance for researching the developmental origins of health and disease.

Effect of Selenium Sources on Laying Performance, Egg Quality Characteristics, Intestinal Morphology, Microbial Population and Digesta Volatile Fatty Acids in Laying Hens.

Simple SummaryDeficiency in microminerals (e.g., selenium) is a global issue, with a consequent manifestation of health-related challenges in both humans and animals, and is associated with poor animal production and reproductive performance. Due to the health benefit of selenium, dietary supplementation of organic selenium for caecum microbes can be important for balance, maintenance, and performance requirements. Food products containing selenium (eggs) are often referred to as “functional foods”, and are simple to produce from organic sources (selenium). Dietary supplementation with bacterial selenoproteins improves performance index, egg quality parameters, intestinal villus height, and increases the population of beneficial, and decreases harmful caecum microbes in hens, according to the current study. Therefore, it can be used to effectively produce Se-rich eggs as a functional food, while also supporting the caecum microbiome.The use of toxic and less bioavailable inorganic selenium can now be supplemented with an alternative organic source from bacterial species in nutrition for human and animal benefit. This study investigated the effects of selenium sources on laying performance, egg quality characteristics, intestinal morphology, caecum microbial population, and digesta volatile fatty acids in laying hens. One hundred and forty-four Lohman Brown Classic laying hens, at 23 weeks of age, were divided into four experimental groups (36 hens in each), differing in form of Se supplementation: no Se supplementation (Con), 0.3 mg/kg of inorganic Se in the form of sodium selenite (Na2SeO3), 0.3 mg/kg of organic Se from selenium yeast (Se-Yeast), and 0.3 mg/kg of organic Se from Stenotrophomonas maltophilia (bacterial organic Se, ADS18). The results showed that different dietary Se sources significantly affected laying rate, average egg weight, daily egg mass, feed conversion ratio (FCR), and live bodyweight (LBW) (p < 0.05). However, average daily feed intake and shell-less and broken eggs were unaffected (p > 0.05) among the treatment groups. The findings revealed that selenium sources had no (p > 0.05) effect on egg quality (external and internal) parameters. However, eggshell breaking strength and Haugh unit were significantly (p < 0.05) improved with organic (ADS18 or Se-yeast) Se-fed hens compared to the control group. In addition, egg yolk and breast tissue Se concentrations were higher (p < 0.05) in the dietary Se supplemented group compared to the control. Intestinal histomorphology revealed that hens fed ADS18 or Se-Yeast groups had significantly (p < 0.05) higher villi height in the duodenum and jejunum compared to those fed Na2SeO3 or a basal diet. However, when compared to organic Se fed (ADS18 or Se-Yeast) hens, the ileum villus height was higher (p < 0.05) in the basal diet group; with the lowest in the SS among the treatment groups. A significant increase (p < 0.05) of Lactobacilli spp. and Bifidobacteria spp., and a decrease of Escherichia coli and Salmonella spp. population were observed in the organic (ADS18 or Se-yeast) compared to inorganic supplemented and control hens. The individual digesta volatile fatty acid (VFA) was significantly different, but with no total VFA differences. Thus, bacterial selenoprotein or Se-yeast improved the performance index, egg quality characteristics, egg yolk and tissue Se contents, and intestinal villus height in laying hens. Moreover, caecum beneficial microbes increased with a decrease in the harmful microbe population and affected individual cecal volatile fatty acids without affecting the total VFA of the laying hens digesta.

The transfer of amino acids and minerals to the egg yolk and to the yolk sac of their progeny is affected by breeder age.

This study aimed to assess the effects of breeder age on egg quality and amino acid and mineral transfer to the egg yolk and yolk sac of newly hatched chicks. Three ages (32, 42 and 52weeks) of the same commercial flock of Hubbard breeders were studied. A total of 465 eggs were used for each age, with 60 being used for determining egg quality and amino acid and mineral content of yolk, and 405 for incubation period to obtain and evaluate the yolk sac of chicks. Breeders aged 52weeks had heavier eggs and a higher percentage of yolk (p<0.05), whereas 32-week-old breeders had higher eggshell percentage and thickness (p<0.05). The percentage of protein deposited in egg yolk for 52-week-old breeders was higher than that for 32- and 42-week-old breeders (p<0.05). Percentages of methionine, cysteine, met+cysteine, lysine, threonine, tryptophan, arginine and isoleucine in egg yolk for 32-week-old breeders were higher than that for 42- and 52-week-old breeders (p<0.05). The transfer from breeder of phosphorus, potassium, calcium, magnesium, copper, iron, manganese and zinc to the yolk of eggs from 32-week-old breeders was greater than that for eggs from 42- and 52-week-old breeders (p<0.05). Chicks from 32-week-old breeders had greater deposition of phosphorus and calcium in the yolk sac (p<0.05). Breeder age did not affect the deposition of potassium, magnesium, copper, iron, manganese and zinc in the yolk sac of newly hatch chicks (p>0.05). It can, however, be concluded that younger breeders deposit more amino acids and minerals in egg yolk, while embryos of older breeders seem to use the nutrients present in the yolk more efficiently during embryonic development.

The effect of different vegetable oils on energy content of table eggs yolk

Article Details: Received: 2020-08-31 | Accepted: 2020-11-16 | Available online: 2021-06-30 https://doi.org/10.15414/afz.2021.24.02.137-140 The aim of this study was to analyse the gross energy (GE) value of egg yolk from hens feed with different vegetable oils addition and based on gained results calculate the linear regression between GE and dry matter % (DM) in yolk. Total 66 hens Lohmann brown lite were divided in to 11 groups according to concentration and type of used vegetable oil (pumpkin oil 3%, flax seed oil 3%, indian hemp seed oil 2.5% and 5%, grape seed oil 2.5% and 5%, olive oil 2.5 and 5%, apricot seed oil 2.5% and 5%). Hens were in 40 th week of life and were housed per 6 in cage. From each group eight eggs were randomly selected. In total 88 egg yolks were separated and analysed for DM and GE content. The highest yolk GE was detected in group with 3% pumpkin oil addition (1639 kJ/100g) followed by groups with 2.5 and 5% indian hemp seed oil addition 1632 and 1632 kJ/100g, respectively. Difference between these three groups compared to yolk GE content (1584 kJ/100g) in control group was significant (P&lt;0.05). All other added oils increased the yolk GE (P&gt;0.05). GE concertation of yolk can be calculated as follows: GE = -17.34 + (32.73 * DM), R 2 = 0.819. Keywords: laying hens, egg yolk gross energy, regression References Antova, G. A. et al. (2019). Comparative analysis of nutrient content and energy of eggs from different chicken genotypes. Journal of the Science of Food and Agriculture, 99(13), 5890–5898. https://doi.org/10.1002/jsfa.9863 AOAC. (2000). Official methods of analysis AOAC. International 17th edition. Association of Analytical Communities, Gaithersburg. Benková, J. (2008). Artificial hatching of poultry is nothing simple. Slovenský chov, 13(6), 45-47. In Slovak. Gálik, B.et al. (2014). The effect of dietary Rhus coriaria L. on table eggs yolk nutrients composition. Acta fytotechnica et zootechnica, 17(3), 93–95. https://doi.org/10.15414/afz.2014.17.03.93-95 Herkeľ, R. et al. (2016). Fatty acid profile and nutritional composition of table eggs after supplementation by pumpkin and flaxseed oils. Acta Veterinaria Brno, 85(3), 277–283. https://doi.org/10.2754/avb201685030277 Hrnčár, C. &amp; Bujko, J. (2012). Effect of pre-storage incubation of hatching eggs on hatchability of poultry. Acta fytotechnica et zootechnica, 15(2), 34-37. http://www.acta.fapz.uniag.sk/journal/index.php/on_line/article/view/31 Javad, N. et al. (2011). Effects of amino acids and metabolizable energy on egg characteristics and broiler breeder performance. African Journal of Biotechnology, 10(49), 10066–10071. https://doi.org/10.5897/ajb11.1268 Noble, R. C. et al. (1996). Yolk lipids and their fatty acids in the wild and captive ostrich (Struthio camelus). Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 113(4), 753–756. https://doi.org/10.1016/0305-0491(95)02097-7 Pearson, R. A. &amp; Herron, K. M. (1981). Effects of energy and protein allowances during lay on the reproductive performance of broiler breeder hens. British Poultry Science, 22(3), 227–239. https://doi.org/10.1080/00071688108447881 Pištěková, V. et al. (2011). The quality comparison of eggs laid by laying hens kept in battery cages and in a deep litter system. Czech Journal of Animal Science, 51(7), 318–325. https://doi.org/10.17221/3945-cjas Radu-Rusu, R. et al. (2014). Chemical features, cholesterol and energy content of table hen eggs from conventional and alternative farming systems. South African Journal of Animal Science, 44(1), 33. https://doi.org/10.4314/sajas.v44i1.5 Roe, M. et al. (2013). Nutrient analysis of eggs. Analytical Report (revised version). UK Government, Department of Health and Social Care. Retrieved December 10, 2020 from https://assets.publishing.service.gov.uk/government/uploads/system/ uploads/attachment_data/file/167973/Nutrient_analysis_of_ eggs_Analytical_Report.pdf Roztočilová, A. et al. (2018). Effect of purple wheat RU 687- 12 on performance parameters of laying hens at the end of the lay. In NutriNET 2018. Proceedings of reviewed scientific papers. Mendel University in Brno (pp. 92–97). Vojtaššáková, A. et al. (2000). Milk and eggs. Food nutrition tables. Výskumný ústav potravinársky, Bratislava. In Slovak. Van der Wagt, I. et al. (2020). A review on yolk sac utilization in poultry. Poultry Science, 99(4), 2162–2175. https://doi.org/10.1016/j.psj.2019.11.041 Zhang, Y. (2016). Studies on chicken hatchability and its relation with egg yolk metabolites. Dissertation thesis. GeorgAugust-University, Göttingen.

Fatty acid profiles of egg yolk and albumen from Cemani and White Leghorn chickens

The composition of the yolk and albumen content in the egg was 60 and 30%, respectively. The purpose of this paper is to examine the fatty acid profile (FA) of egg yolk and albumen in cemani and white leghorn chickens. Cemani and white leghorn chickens were given a commercial feed of 110 g/head/day, and drinking water was given ad libitum. Two fresh eggs from each hen were used in this study to examine egg yolk and albumen fatty acids by gas chromatography. The data obtained were analyzed statistically with an independent sample T-test. The results showed that the FA profiles of egg yolk and albumen were not significantly different (P>0.05) for the parameters of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) from chicken. Cemani and white leghorn chickens, monounsaturated fatty acids (MUFA) are found in more amounts than SFA and PUFA in egg yolks and albumen. It can be concluded that the FA profiles of cemani and white leghorn chickens are almost the same.

Effects of Linseed Meal and Carotenoids from Different Sources on Egg Characteristics, Yolk Fatty Acid and Carotenoid Profile and Lipid Peroxidation.

The present study aimed to evaluate the effect of supplementing the diet of laying hens with linseed meal and carotenoids from different sources on egg characteristics, yolk fatty acid and carotenoid profile, and lipid peroxidation. A 4-week experiment was conducted on 168 Lohmann Brown layers (43 weeks of age), assigned to four dietary treatments (42 hens/group; 21 replicate/groups with 2 birds/pen) consisting of a control diet (C) and three diets simultaneously supplemented with 6% linseed meal and 2% dried kapia pepper (E1), 2% dried sea buckthorn pomace (E2) and 2% dried carrot (E3). Every 2 weeks, 18 eggs/group/period were collected randomly from each group and used to determine the egg quality and nutritional parameters. The results showed that dietary linseed meal and carotenoids sources improved egg color, carotenoids’ accumulation in egg yolk and fatty acid profile, especially the n-3 PUFA content. Dietary carotenoids supplementation reduced, n-6/n-3 ratio, cholesterol content of the egg yolk and improved yolk pH, egg thickness and yolk oxidative stability. In conclusion, the use of these sources of carotenoids in the linseed meal enriched diets could be an effective way to improve the nutritional properties of the eggs without affecting their quality and consumer’s safety.

Choline and methionine supplementation in layer hens fed flaxseed: effects on hen production performance, egg fatty acid composition, tocopherol content, and oxidative stability

Choline is an essential nutrient in laying hen diets and is needed for the formation of phosphatidylcholine (PC), that serves as a rich source of long chain (≥20 C) n-3 fatty acids (FA) in eggs. Methionine (Met) is the first limiting amino acid in layer hen diets and serves as a lipotropic agent with antioxidant properties. The objectives of the current study is based on the hypothesis that choline and Met supplementation will enhance egg PC and n-3 FA status, lipid stability, and production indices in layer hens fed flaxseed. Ninety-six, 40-wk-old laying hens (W-36 White Leghorns) were randomly allocated to 4 treatment groups, with 6 replicates containing four hens per cage. Hens were fed corn-soybean meal-based diet containing 0% flaxseed (Control), 15/100 g flaxseed (Flax), Flax+50% more methionine requirement for W-36 White Leghorns (Flax+Met), or Flax+0.15g/100g choline chloride (Cho) (Flax+Cho). All experimental diets were isocaloric and isonitrogenous and fed for a period of 120 d. Egg production and egg mass (g/hen/d) was higher for Flax+Met and Flax+Cho when compared to Flax and Control (P < 0.05). Egg weight was greater (P < 0.05) among hens fed the Control and Flax+Cho diets compared to Flax diet. Feeding flaxseed to hens led to over 6-fold increase in total n-3 FA. Choline supplementation increased egg α-tocopherol content (P < 0.05) while reducing lipid oxidation products measured as thiobarituric acid reactive substances in egg yolk (P < 0.05). Neither Met nor Cho had any impact on docosahexaenoic (22:6 n-3) acid concentration in eggs from hens fed flaxseed. However, addition of Met and Cho to layer diets increased docosapentaenoic acid (22:5 n-3) levels in eggs from hens fed flaxseed (P < 0.05). The PC content was lower in Control and Flax+Met (P < 0.05) when compared to Flax+Cho group. No difference was found in total lipid or phosphatidylethanolamine content of eggs (P > 0.05). The results from the current study suggest that n-3 FA content of egg yolk can be greatly increased by feeding flaxseed but reduced egg production. However, dietary Met and Cho can improve production performance in hens fed flaxseed-containing diets. Addition of Cho to flaxseed increased in egg weight, yolk α-tocopherol levels, PC content and oxidative stability of eggs when compared to hens fed flaxseed. Met and choline could be used in flaxseed (>15%) to increase egg production and egg mas.

Use of extruded eggshell as a calcium source substituting limestone or oyster shell in the diet of laying hens.

The nutritional values of limestone, oyster shell and extruded eggshells were evaluated using different methods. In total, 120 ready‐to‐lay pullets, 18‐week‐old ISA Brown were distributed into six dietary groups, namely D1 (4% limestone), D2 (8% limestone), D3 (4% oyster shell), D4 (8% oyster shell), D5 (4% eggshell) and D6 (8% eggshell), to assess the effect of calcium sources on egg production, egg quality, dry matter and cholesterol content of the egg. Kitchen‐extruded eggshell contained 98.52, 4.24, 29.75 and 14.82% DM, CP, Ca and P, whereas hatchery‐extruded eggshell contained 99.20, 13.80, 25.53 and 13.87% DM, CP, Ca and P, respectively. Limestone and Oyster shells contained 99.60 and 99.51% DM, and 37.12 and 35.20% Ca, respectively. Body weight, egg, hen day and egg mass production, and FCR did not differ among diets (p > .05). Egg production tended to increase with the increase of hen‐housed egg production (p < .001) in D6, followed by D2, D5, D3, D4 and D1, respectively. The lowest production cost and the highest net profit were observed in D6, followed by D2, D4, D5, D1 and D3, respectively. Diet with 8% Ca sources performed better than the diets with 4% Ca sources in terms of egg quality and dry matter content, where D6 was comparable to D2 or D4. The weight of egg, albumen, yolk, eggshell, dry yolk and yolk–albumen ratio increased, while dry albumen and eggshell weight, eggshell strength and thickness, Haugh unit, yolk index and egg‐specific gravity decreased with the increase in bird's age. The cholesterol content of yolk was statistically similar among diets. Therefore, no adverse effect of calcium sources on the production of laying hen was observed. Of these, extruded eggshell especially the 8% extruded eggshell may be beneficial to use in the diet of laying hen for producing a quality, safe and profitable egg.

Comparison of Performance, Egg Quality, and Yolk Fatty Acid Profile in Two Turkish Genotypes (Atak-S and Atabey) in a Free-Range System.

Simple SummaryIn recent years, consumers have shown increased interest in healthy and safe food produced under improved animal welfare standards. Therefore, production systems proving outdoor access have gained popularity, increasing the need for knowledge on genotypes suitable for free-range systems. This study aimed to investigate the suitability of two Turkish layer genotypes, Atak-S (brown) and Atabey (white), in a free-range system. We evaluated laying performance, egg quality parameters, and yolk fatty acid profile. The egg production was higher in Atabey than Atak-S, whereas the eggs from Atak-S hens tended to be heavier and had a stronger shell structure than eggs from Atabey hens. Furthermore, eggs from Atabey hens had improved egg yolk and albumen content compared to eggs from Atak-S hens. The total saturated fatty acid content in yolk was higher in Atabey eggs than in Atak-S eggs at 56 weeks of age, whereas a higher yolk color score was observed in Atak-S eggs than in Atabey eggs. Our results could help free-range egg producers to improve production, as well as satisfy consumer demands regarding egg quality in organic production.Consumer interest in buying eggs from animal welfare-friendly systems with outdoor access is increasing, leading to an increase in the need for knowledge on genotypes suitable for free-range systems. Two Turkish laying hen genotypes, Atak-S (brown, n = 210) and Atabey (white, n = 210), were reared in a free-range system from 19–72 weeks of age, and their suitability for the system was assessed based on laying performance, egg quality, and yolk fatty acid profile. Mean hen-day and hen-housed egg production were found to be higher in Atabey than Atak-S (p < 0.01). The brown eggs from Atak-S hens tended to be heavier than the white eggs from Atabey hens (p < 0.01). Brown eggs obtained from Atak-S hens had a stronger shell structure (p < 0.01), while white eggs from Atabey hens had higher mean yolk index, albumen index, and Haugh unit than brown eggs (p < 0.05). At 56 weeks of age, total saturated fatty acid content in yolk was higher in white eggs than in brown eggs (p < 0.01). These findings related to genotype could help free-range egg producers in their choices for more profitable production and for meeting consumer demands on egg quality and egg yolk fatty acid levels.

The Egg Yolk Content in ω-3 and Conjugated Fatty Acids Can Be Sustainably Increased upon Long-Term Feeding of Laying Hens with a Diet Containing Flaxseeds and Pomegranate Seed Oil

Long-term feeding trials examining the incorporation of conjugated linolenic acids (CLnA) into the diet of laying hens are lacking. In the present study, we compared two diets in sixty-six red Sex-Link hens (33 hens/treatment), fed for 26 weeks. The control diet was high in oleic acid, while the test diet was high in α-linolenic acid (ALA) and punicic acid (PunA). No significant differences were observed between treatments for hens’ performance, egg weight and yolk weight. In contrast, dietary ALA and PunA resulted in a significant increase in n-3 PUFA, rumenic acid (RmA) and PunA contents in egg yolk, as well as in the liver, heart, muscle and adipose tissue of the hens. Other conjugated dienes resulting from the metabolism of PunA or RmA also accumulated in the egg yolk and tissues. Unlike DHA, which was exclusively distributed in phospholipids, ALA, RmA and PunA were preferably distributed in triglycerides.

Influences of lead exposure on its accumulation in organs, meat, eggs and bone during laying period of hens

Elevating levels of environmental lead (Pb) results in serious hazards to health of animals and human beings. In this study, daily diet with three different levels of Pb (Pb nitrate at doses of 1, 10, and 100 mg/kg body weight) were fed to ISA Brown layers. It showed that the kidney and liver have the relatively high Pb concentration (2.34 and 0.51 ppm) after culture, while the meat has the Pb concentration as low as 0.07 ppm (lower than the standard of Codex Alimentarius). It was also confirmed that egg laying worked as a potential pathway for hens to excrete Pb as Pb concentrations in eggshell and yolk increased from 0.10 to 3.11 ppm. However, the Pb concentration in egg white remains at a safe level (<0.10 ppm). Furthermore, even the intake of low dose Pb can cause a decline of bone mineral density and bone strength. Raman spot and mapping analysis indicated that carotenoids content in humerus from the hens of high dose group increased significantly, which hence can be applied as an indicator for resist stress. The degradation of bone quality will further damage the health of laying hens. Therefore, Pb exposure not only toxifies organs and reduces physiological features (e.g., body weight and laying rate) instantly, but also hurts poultry via degrading bone quality in long term. Additionally, the probability of excessive Pb in poultry meat is less than those of viscera and eggs, indicating its low risk to food safety.

Tea polyphenols increase the antioxidant status of laying hens fed diets with different levels of ageing corn.

This study was conducted to evaluate the effects of ageing corn levels (stored for 4 years) with or without the supplementation of tea polyphenols (TPP) on the performance, egg quality and antioxidant status of laying hens. A total of 288 Lohmann commercial laying hens (63-week-old) were used under a 2 × 4 factorial arrangement with 4 levels of dietary ageing corn (0%, 25%, 50%, or 100%) and 2 levels of TPP (0 and 600 mg/kg) for 8 wk. Dietary ageing corn linearly decreased (P < 0.05) the egg production, serum total antioxidant capacity (T-AOC), liver glutathione peroxidase (GSH-Px) of laying hens, yolk index, yolk colour, 1,1-diphenyl-2-picrylhydrazyl (DPPH) value and the reducing power value of egg yolk, but it linearly increased (P < 0.05) the feed conversion rate, ovary malondialdehyde (MDA) content of laying hens, and the protein carbonyl content of egg yolk. Tea polyphenol supplementation increased (P < 0.05) the serum T-AOC, serum superoxide dismutase (SOD), liver SOD, liver GSH-Px, ovary SOD, GSH-Px, the expression of antioxidant-related genes of laying hens, albumen height, Haugh unit, DPPH value and the majority free amino acids of egg yolk, but it decreased (P < 0.05) the serum MDA content of laying hens, MDA and protein carbonyl of egg yolk. In conclusion, the ageing corn significantly reduced the performance, egg quality, antioxidant status and egg antioxidant capacity of laying hens, while TPP supplementation partially counteracted the adverse effects, especially antioxidant status and egg antioxidant capacity of laying hens.

Effects of dietary supplementation of bioactive selenium on performance, egg quality and selenium content in the egg yolk of laying hens

Effects of dietary supplementation of bioactive selenium on performance, egg quality and selenium content in the egg yolk of laying hens