Yolk Content Research Articles

Preparation of Salad Dressing Emulsions Using Lentil, Chickpea and Pea Protein Isolates: A Response Surface Methodology Study

AbstractThe effect of pulse protein, egg yolk and oil contents on the physical properties (i.e., static and dynamic rheological behavior, texture) of lentil‐, pea‐ and chickpea‐supplemented salad dressings was studied using a three‐factor central composite design (CCD). Multiple regression equations were developed to describe the effects of the independent variables on several response variables. In general, an increase in oil and emulsifier (pulse protein or egg yolk) contents modified the rheological and textural properties and led to either a linear or a nonlinear increase in several parameters, including , m, ηap, σ0, Q(t)% and firmness. Response surface methodology was used to optimize the salad dressing formulations based on selected response variables, which were either maximized or minimized, or targeted using average values of parameters for several commercial salad dressings. The validation test confirmed the overall adequacy of the response surface models in predicting specific properties of the set formulations.Practical ApplicationsThe use of egg yolk as an emulsifier in the formulation of salad dressings may be a concern for those with high cholesterol. Proteins prepared from pulses may be promising value‐added replacements for such reduced egg‐yolk emulsion‐type food products. We have demonstrated the feasibility of making pulse protein‐supplemented salad dressings with physical properties similar to those of commercial dressings by varying levels of pulse protein, egg yolk and oil in salad dressing emulsion systems.

Kinematic Response of Barbari and Sirohi Buck Spermatozoa to High Egg Yolk Concentration in Semen Extender

The experiment was designed to evaluate kinematic characteristic exhibited by spermatozoa in diluted Barbari and Sirohi buck semen using computer assisted semen analysis. Four normal healthy adult bucks (2 Barbari and 2 Sirohi) reared at the experimental goat sheds of department were selected for semen collection. Semen was collected twice a week using artificial vagina. A total of 8ejaculates (sixteen ejaculates from each breed) were collected from each buck. After initial semen evaluation, ejaculates from similar breed were pooled. The pooled semen sample of two breeds were dilutedwith TRIS based extender containing 20 per cent egg yolkto final concentration of 100×106 spermatozoa per ml. Motility patterns and path velocities of spermatozoa were evaluated using computer assisted semen analyser (CASA). It was observed that proportion of spermatozoa exhibiting rapid progression were highest in both the breeds, following by slow progression and non-progression. A significantly (p<0.01) higher values of non-progressive spermatozoa were observed in Barbari buck semen. Different path velocities viz. VCL (μm/sec), VAP (μm/sec), VSL (μm/sec), Lin (%), Str(%), WOB(%), BCF(hz), ALH(μm) and DNC(μm2/sec) exhibited by spermatozoa were recorded during the experiment. The VCL (μm/sec), ALH(μm) and DNC(μm2/sec) were significantly(p<0.01, p<0.05) in Barbari buck semen while a significantly(p<0.01, p<0.05) higher values of VSL, Lin (%), Str (%), WOB(%)and BCF (hz) were observed for Sirohibuck. The result indicated that Barbari buck spermatozoa covered more distance per unit time in the vertical direction (Y-axis) and short X axial movements (horizontal movement), while the spermatozoa of Sirohi Buck moved at slower velocity with more distance covered in horizontal direction (X axis) and lesser vertical displacementresulting in lower values of VCL and higher values of VAP and VSL as compared to Barbari buck. So, it can be concluded that a variable response is exhibited by Barbari and Sirohi buck spermatozoato egg yolk concentration, indicating a breed specific variation in motion characteristic and path velocities of spermatozoa.

Effect of Different Egg Yolk Concentration on Chilled Barbari Buck Semen During Short Term Storage

The experiment was designed to evaluate the optimal concentration of egg yolk in extender for diluting Barbari buck semen during short-term storage at 4°C. A total of four Barbari bucks were used as semen donors during the experiment. The observed mean (±SE) valuesrecorded for percent live spermatozoa ranged from 63.5 ± 1.08 to 75.33 ± 0.99, percent progressive motile spermatozoa ranged from 54.17 ± 1.56 to 69.00 ± 0.82, percentage of HOST positive spermatozoa ranged from 60.83 ± 1.62 to 71.33 ± 1.54 while the acrosomal integrity ranged from 58.67 ± 1.563 to 71.33 ± 0.92 during the experiment. Three different patterns to evaluate capacitation like changes were observed under fluorescence. The observed mean (±SE) values of pattern F ranged from 45.67 ± 1.54 to 62.33 ± 1.14, pattern B ranged from 22.00 ± 0.73 to 28.83 ± 1.58 while pattern AR represent capacitated spermatozoa ranged from 15.67 ± 0.71 to 25.00 ± 0.62 during the experiment. A significantly higher value (p<0.01) of different seminal attributes was recorded in samples diluted with 15% egg yolk followed by 10%, 20%, 5% and 2.5%. The results recorded during the experiment indicates that 15% egg yolk in the semen extender is best suited for semen dilution during chilling process in Barbaribuck.

The Effects of Nutrient Concentration, Addition of Thickeners, and Agitation Speed on Liquid Fermentation of Steinernema feltiae.

Entomopathogenic nematode production in liquid fermentation still requires improvements to maximize efficiency, yield, and nematode quality. Therefore, this study was aimed at developing a more suitable liquid medium for mass production of Steinernema feltiae, by assessing the effects of nutrient concentration, thickeners (primarily agar), and agitation speed on infective juvenile (IJ) yield. Base medium (BM) contained yeast extract (2.3%), egg yolk (1.25%), NaCl (0.5%), and corn oil (4%). All media were inoculated with Xenorhabdus bovienii, and 2 d later, with 2-d-old S. feltiae juveniles. For the nutrient concentration experiment, we evaluated the base medium versus a modified base medium containing all the components, but with 3× concentrations of yeast extract (6.9%), egg yolk (3.75%), and corn oil (12%). The nematodes and bacteria were cultured in 150-ml Erlenmeyer flasks containing 50 ml of liquid medium at (25°C) and 180 rpm on a rotary shaker incubator. To assess the effect of thickeners, IJs were inoculated in BM with agar (0.2%), carrageen (0.2%), and carboxymethyl cellulose (0.2% and 0.5%). The addition of 3× more nutrients relative to the BM resulted in a significantly lower yield of nematodes. For agar and agitation speed experiments, five levels of agar in the BM (0%, 0.2%, 0.4%, 0.6%, and 0.8% agar) and two agitation speeds (180 and 280 rpm) were evaluated for production. Increasing agitation speed from 180 to 280 rpm and higher levels of agar in the medium (> 0.2%) significantly increased the yield of bacteria. At the lower agitation speed, media amended with 0.4% and 0.6% agar produced higher nematode yields compared to media without agar. Media with 0.2% and 0.8% agar resulted in intermediate levels of nematode production. At the higher agitation speed, media supplemented with 0.8% agar resulted in the lowest yield of nematodes when compared to the other media tested. Results indicated that increasing nutrient concentration levels was detrimental to nematode production. Also, media containing agar (0.4% and 0.6%) increased nematode yields when cultures were grown at low agitation speed. When IJs were used as the inoculum, 0.2% agar also enhanced recovery and nematode yield at the higher agitation speed.

Effects of low sodium salt on the sodium and potassium content,hardness and protein secondary structure of preserved eggs

Fresh duck eggs were used to prepare preserved eggs. The sodium and potassium content,gel hardness,egg white protein secondary structure and sensory quality of preserved eggs obtained from low sodium salt were investigated,which could provide a new way to reduce the sodium content of preserved eggs and a new direction to process low sodium preserved eggs.The results showed sodium content of egg white was reduced by21%,and sodium content of egg yolk was decreased by 30% in 100% low sodium salt treatment compared to ordinary salt treatment. Different proportion of low sodium salt treatments had no significant effect on gel hardness and egg white protein secondary structure( p > 0.05). Finally,70% proportion of low sodium salt treatment could provide excellent sensory quality for preserved eggs.

Naupliar and Metanaupliar Development of Thysanoessa raschii (Malacostraca, Euphausiacea) from Godthåbsfjord, Greenland, with a Reinstatement of the Ancestral Status of the Free-Living Nauplius in Malacostracan Evolution.

The presence of a characteristic crustacean larval type, the nauplius, in many crustacean taxa has often been considered one of the few uniting characters of the Crustacea. Within Malacostraca, the largest crustacean group, nauplii are only present in two taxa, Euphauciacea (krill) and Decapoda Dendrobranchiata. The presence of nauplii in these two taxa has traditionally been considered a retained primitive characteristic, but free-living nauplii have also been suggested to have reappeared a couple of times from direct developing ancestors during malacostracan evolution. Based on a re-study of Thysanoessa raschii (Euphausiacea) using preserved material collected in Greenland, we readdress this important controversy in crustacean evolution, and, in the process, redescribe the naupliar and metanaupliar development of T. raschii. In contrast to most previous studies of euphausiid development, we recognize three (not two) naupliar (= ortho-naupliar) stages (N1-N3) followed by a metanauplius (MN). While there are many morphological changes between nauplius 1 and 2 (e.g., appearance of long caudal setae), the changes between nauplius 2 and 3 are few but distinct. They involve the size of some caudal spines (largest in N3) and the setation of the antennal endopod (an extra seta in N3). A wider comparison between free-living nauplii of both Malacostraca and non-Malacostraca revealed similarities between nauplii in many taxa both at the general level (e.g., the gradual development and number of appendages) and at the more detailed level (e.g., unclear segmentation of naupliar appendages, caudal setation, presence of frontal filaments). We recognize these similarities as homologies and therefore suggest that free-living nauplii were part of the ancestral malacostracan type of development. The derived morphology (e.g., lack of feeding structures, no fully formed gut, high content of yolk) of both euphausiid and dendrobranchiate nauplii is evidently related to their non-feeding (lecithotrophic) status.

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

Dietary lutein and its food sources have gained great attention due to its health-promoting effects on humans, especially for certain eye diseases. However, relative bioavailability (RBV) of lutein among lutein-rich feed ingredients that lead to lutein-enriched egg production has not been determined. Thus, the RBV of lutein in corn distillers dried grains with solubles (DDGS) as compared to lutein in corn gluten meal (CGM) was evaluated based on lutein retention in egg yolk. Increasing inclusion levels of DDGS or CGM in diets increased (linear, P < 0.01) Roche colour score and lutein concentrations of egg yolk without affecting laying performance. Multiple regression analysis revealed that the bioavailability of lutein in DDGS was less (P < 0.05) than that of lutein in CGM, with the RBV of lutein in DDGS being 61.6% when the bioavailability of lutein in CGM was assumed to be 100% for lutein retention in egg yolk. The results of the present experiment indicate that the DDGS can be a potential ingredient for laying hens to improve egg yolk colour and lutein concentrations of egg yolk although lutein in DDGS is less bioavailable than lutein in CGM. © 2015 Society of Chemical Industry.

38 QUAIL EGG YOLK IN CITRATE EXTENDER IS SUITABLE FOR CRYOPRESERVATION OF NGUNI BULL SEMEN

Traditionally, commercial hen egg yolk has been used in extenders or freezing media because of its easy availability. However, the use of quail egg yolk has not been used for preserving Nguni bull semen. The aim of the study was to compare the suitability of different quail egg yolk concentrations (5, 10, 15, and 20%) for cryopreserving Nguni bull semen. Semen was collected from 14 stud Nguni bulls with the aid of electro ejaculator. Collected semen samples were kept in a thermos-flask containing warm water at a temperature of 37°C and transported to the laboratory for further analyses. The sperm motility traits were evaluated using computer-aided sperm analysis prior extension. Semen samples were then randomly allocated into 5, 10, 15, and 20% of quail egg yolk and 20% concentration of chicken egg yolk (control) in citrate extender. The extender was supplemented with 12% of glycerol (Seshoka et al. 2012) as a cryoprotectant, and semen samples were diluted (1 : 2) and equilibrated for a period of 4 h at 5°C. After equilibration, semen samples were loaded into 0.25-mL straws, placed into a controlled rate programmable freezer, and stored in a LN tank (–196°C) until thawing. Frozen semen straws were thawed in a water bath at 37°C for 1 min. Thawed semen was evaluated for sperm motility traits using a computer-aided sperm analysis system. Data were analysed with ANOVA. A significant difference was recorded between fresh total sperm motility rate (99%) and frozen-thawed semen samples with either 5% (87.3%) quail or 20% (87.6%) chicken egg yolk citrate extender compared with 10% (92.6%), 15% (91.2%), or 20% (89.9%) quail egg yolk citrate extender. Moreover, fresh semen also resulted in a significantly higher progressive sperm motility rate (39.3%) as compared with frozen-thawed with 5% (26.2%) or 20% quail (28.5%) or 20% chicken (22.7%) egg yolk citrate extender. The results also demonstrated that the use of 10, 15, and 20% quail egg yolk in citrate extender yielded comparable results on total sperm motility with fresh semen as compared with 5% quail and 20% chicken egg yolk. In conclusion, quail egg yolk extender provided sufficient cryo-effectiveness to cryopreservation of Nguni bull semen.

Effects of rice bran on performance, egg quality, oxidative status, yolk fatty acid composition, and fatty acid metabolism-related gene expression in laying ducks

The study was designed to evaluate the effects of different dietary levels of rice bran (RB) in laying duck diets on performance, egg quality, oxidation status, egg yolk fatty acid composition, and hepatic expression of fatty acid metabolism-related genes. Longyan females (1080) with similar BW at 19 wk of age were randomly assigned to 6 dietary treatments, each consisting of 6 replicates of 30 birds. The basal diet (I) was a typical corn-soybean ration while the experimental diets (II to VI) substituted RB for corn and wheat bran and a small reduction of soybean meal. The level of substitution in diets (II to VI) was 6%, 12%, 18%, 24%, and 30%, respectively. The experiment lasted for 12 wks. Average egg weight and daily egg mass decreased linearly as the level of RB inclusion increased (P < 0.001) and feed conversion ratio linearly increased (P < 0.001). The proportions of C14:0 and C18:0 and total saturated fatty acids (SFA) in egg yolk linearly decreased with increasing RB, and many of the key polyunsaturated fatty acids (PUFA), like C18:2 n-6 and C18:3 n-3, linearly increased (P < 0.001), but not those of C20:5 n-3 and C22:6 n-3. There were linear decreases (P < 0.001) in hepatic abundance of FAS and SREBP1 transcripts, with a substantial reduction to about 30% those of ducks fed the control diet; there were no treatment effects on productive performance, eggshell thickness, strength, Haugh unit, antioxidation status, and egg yolk cholesterol or triglyceride content (P > 0.05). In conclusion, the current study suggests that ducks from 19 to 31 wk could be fed diets with up to about 18% RB without effect on the number of eggs produced, egg quality, and oxidative status. Increasing amounts of RB linearly increased egg yolk concentrations of key fatty acids like C18:2 n-6 and C18:3 n-3 and decreased the hepatic abundance of FAS and SREBP-1 transcripts.

Ciprofloxacin residue and their impact on biomolecules in eggs of laying hens following oral administration

The present study was designed to evaluate Ciprofloxacin residue and their impact on some biomolecules (albumin, total protein and cholesterol) in eggs of laying hens after oral administration. For that purpose, One group (A) of laying hens (n = 20) were orally administered 10 mg⁄kg ciprofloxacin for five consecutive days. The second group (n = 10) was untreated controls. Eggs were collected from day one of treatment and up to 25 days after withdrawal of treatment. Egg white and yolk from each egg were separated, and ciprofloxacin residues and biomolecules were analyzed by high-performance liquid chromatography method with fluorescence detection and humalyzer having commercial assay kits respectively. Ciprofloxacin was detectable in egg white on the first day of treatment in higher concentrations (1755 μg⁄kg) while at lower concentrations (362 μg⁄kg) in egg yolk. In both medium, concentrations increased during five days treatment period. After withdrawal of treatment, eight days and fourteen days were required to deplete the drug residue below the established LOD in albumen and yolk respectively. On the other hand, cholesterol level increased while albumin and total protein level decreased during treatment period. All these biomolecules returns to their normal level at about seventeenth or eighteenth day from the day of treatment. In all cases, the differences in drug residue concentrations and biomolecules concentrations during treatment and post treatment in egg were found significant. Based on the time needed for residue to deplete below the LOD, we can estimate that, within twenty days of treatment period, egg contents could contain harmful residue which can deplete the nutritional value of egg and thus could cause severe disease for consumer as well whereas it is safe after that period.

Effect of starting body fat content and genotype of laying hens on the changes in their live weight, body fat content, egg production and egg composition during the first egg-laying period

A total 120 laying hens (60 TETRA BLANCA white egg layers and 60 TETRA SL brown egg layers) were selected from 250 TETRA BLANCA and 250 TETRA SL pullets based on their predicted body fat content by means of computed tomography (CT) at 16 weeks of age. Three groups of pullets were chosen for the investigation with the highest (n = 20), lowest (n = 20) and average (n = 20) body fat content.Changes in the live weight, body fat content, egg production and egg composition of the chosen animals were recorded at 32, 52 and 72 weeks of age.Based on the results, it was established that differences in starting body fat content of the hens remained the same during the experimental period. The differences between the two extreme groups were statistically significant at each age.The starting body fat content of the hens affected the rate of egg production, i.e. hens with high starting body fat content produced 11–14 eggs fewer than the hens with a low or average body fat content but had no effect on the composition of the eggs.Genotype affected almost all of the examined traits: TETRA BLANCA hens had lower live weight and higher body fat content during the experimental period and produced fewer eggs with lower albumen and higher yolk, dry matter and crude fat content than the TETRA SL hens.

Influence of soy oil source and dietary supplementation of vitamins E and C on the oxidation status of serum and egg yolk, and the lipid profile of egg yolk

An experiment was conducted to determine the effects of adding vitamins E and C to diets containing 3.5% refined soy oil (SO), recycled soy oil (RSO), or acidulated soy oil soapstocks (ASS) on 1) fatty acid (FA) profile, and cholesterol, triglyceride (TG) and α-tocopherol (α-T) concentrations of yolk, and 2) the oxidation status of serum and yolk. Twelve dietary treatments, using 3 oil sources, 2 levels of vitamin E (0 vs. 250 mg/kg), and 2 levels of vitamin C (0 vs. 250 mg/kg), were prepared. A total of 300 W36 Hy-line laying hens, from 44 to 56 weeks of age, were placed in 60 cages (5 birds/cage) and 5 cages were randomly assigned to one of the 12 diets. Blood samples and eggs were collected after 84 d on trial. No interactions among main effects were found for any of the traits studied. Oil sources had little effects on the FA profile of the yolk, except for C18:3 that was higher (P-value of < 0.01) in the hens fed SO than those fed RSO or ASS. Vitamin E supplementation significantly (P-value of < 0.05) increased the concentration of C16:0, C18:0, and C16:1 but decreased that of C18:2 and C22:6n3 in the yolk. Vitamin C supplementation significantly (P-value of < 0.05) increased C18:0 and C18:3 concentrations in the yolk but decreased the n6 to n3 FA ratio. The concentrations of cholesterol and triglyceride in serum and yolk were not affected by dietary treatment but α-tocopherol concentration increased (P-value of < 0.01) by the dietary vitamin E. Compared with the hens fed the SO diets, malondialdehyde (MDA) concentration in serum was higher with RSO diet but lower with ASS diet. Vitamin E and vitamin C supplementation decreased (P-value of < 0.05) serum MDA. Yolk FA profile was affected not only by the FA profile of the oil source used in diet, but also by the supplementation of vitamin E and C. The results showed that triglyceride profile, but not cholesterol content, of egg was affected by fatty acid profile of the supplemental oil and the vitamin C and E supplementations.

Production of Bio-omega-3 eggs through the supplementation of extruded flaxseed meal in hen diet.

BackgroundThe full-fat flaxseed meal has obtained relatively new flourished concept as staple chicken feedstuff for the production of designer eggs. However, unprocessed flaxseed also encloses well documented anti-nutritional factors which are associated with growth depression of laying hens. The present research work was carried out to evaluate the impact of full-fat extruded flaxseed meal supplemented diets on productivity performance of hens and production of modified ω-3 fatty acids-enriched eggs.MethodsThe full-fat flaxseed meal was extruded at barrel exit temperature (140 °C), screw speed (160 rpm) and feed rate (25 kg/h) for reduction of anti-nutritional compounds. One hundred and sixty, Babcock hens (age 24 weeks old) were selected at random from a large flock and ten hens were placed in each of 16 wire-mesh pens. The experimental diets prepared by supplementation of extruded flaxseed at 10 %, 20 % and 30 % level were fed to hens along with control.ResultsThe extruded flaxseed contained 86 % and 76 % less hydrocyanic compounds and tannin, respectively than the initial material. The hens fed with control diet consumed more feed, possessed heavy body weight and showed higher egg production as compared to hens fed on extruded flaxseed supplemented diets. The loss in body weight and egg production was recorded less for hens fed on 10 % extruded flaxseed supplemented diets as compared to those fed on 30 % extruded flaxseed supplemented diets. None of the experimental diets resulted in significant increase or decrease the total lipids and cholesterol content in egg yolk of hens. The extruded flaxseed supplemented diets resulted in a significant improvement of α-linolenic and docosahexaenoic acid in egg yolk with a concomitant reduction in arachidonic acid. The sensory scores were assigned higher to control eggs. Increasing level of extruded flaxseed in experimental diets decreased the scores for all sensory attributes of eggs.ConclusionThe present study suggested that extruded flaxseed meal up to 20 % can be supplemented in the diets of hens for maximum deposition of α-linolenic acid and docosahexaenoic acid in egg yolk with acceptable detrimental effects on egg traits.

Rheological and textural properties in a bakery product as a function of the proportions of the egg yolk fractions: Discussion and modelling

With the aim of widening our knowledge about the structural changes induced by the components of egg yolk granules and their relevance in baked goods, rheological and other physical parameters have been studied in a real food system and correlated with the proportion of plasma/granules added in each case.For this purpose, the whole egg yolk content was progressively substituted by its high protein-content granular fraction in a muffin recipe until a 100% granular recipe was obtained. Five different formulas, corresponding to different plasma/granules ratios, were used and another formula with 100% granules and containing mono- and diglycerides of fatty acids (E471) was tested too.Flow curves at 25 °C and mechanical spectra at 90 °C were obtained for each substitution in order to evaluate the effect of the granules on the structure of the batter. In addition, other physical parameters of the baked muffins, such as hardness, were determined. The effects of the granular fraction on the aeration of the batter and on the baked muffins were also assessed by means of image analysis.The progressive addition of granular proteins resulted in a non-linear increase in the consistency coefficient, the strength of the interactions and the hardness of the baked muffins, particularly from a plasma/granules ratio lower than 0.75. The addition of emulsifiers reverted the effects observed. These results suggest that the desirable effects of the egg yolk on the textural properties and shape of the muffin are due mainly to the effect of the plasma fraction.

Effect of supplementation of organic zinc on the zinc level and quality traits of eggs in broiler breeders

Broiler breeder hens (264) of 32 weeks of age were distributed randomly in 4 dietary treatments. The dietary treatments were T0: Broiler breeder ration containing 40ppm zinc (basal 29.8 ppm + 10.2 ppm inorganic zinc), T1: T0 + organic zinc (zinc methionine) @ 20ppm, T2: T0 + organic zinc @ 40ppm and T3: T0 + organic zinc @ 60ppm. The experiment was continued from 32 to 48 weeks of age. At 35, 39, 43 and 48 week, the egg quality traits and zinc level in the eggs were assessed. Expect the egg shell thickness, the other studied egg quality parameters viz. egg weight (g), egg length (mm), egg breadth (mm), egg shell thickness without membrane (mm), yolk height (mm), yolk diameter (mm), albumen height (mm), albumen weight (g), yolk weight (g), egg shell weight (g), shape index and Haugh unit of female broiler breeder of different treatments during the experimental period did not differ significantly in all the periods. The zinc content of egg shell of all the groups of broiler breeder birds did not differ significantly at 32 and 39 week of age but at 40 and 48 weeks of study, significantly higher egg shell zinc content was observed in T3 group and lowest in T0. The zinc content in the egg albumen of all the groups of broiler breeder birds did not differ significantly in all the periods of study. Except at 35 weeks, the zinc content of egg yolk and total egg differed significantly with lowest levels was observed in T0. The egg shell thickness and egg shell weight of 40ppm and 60ppm zinc supplemented group were significantly higher than all other groups. Other egg quality traits found to be unaffected among treatment groups.

Effects of supplementing microalgae in laying hen diets on productive performance, fatty-acid profile, and oxidative stability of eggs

The purpose of this trial was to investigate the effects of adding graded levels of dehydrated, whole-cell microalgae (All-G-RichTM, Alltech Inc.) in layer diets on the performance, egg and shell quality, yolk color, oxidative stability, and fatty-acid concentration of eggs. Six replicate groups of 5 Hy-Line W-36 laying hens were assigned to each of 4 dietary treatments. Treatments consisted of feeding a corn-soybean meal control diet alone or supplemented with 1.0, 2.0, or 3.0% All-G-RichTM during a 32-wk production period. Fatty-acid content of egg yolk was analyzed after feeding the experimental diets for 4 wk. The docosahexaenoic acid (DHA) content in egg yolk was linearly increased (P < 0.01) with increasing levels of algae in the diet. There was no effect of dietary treatments on production performance of layers in the entire trial period. Egg weight and eggshell quality were not affected by dietary treatments. Supplements of 2 or 3% All-G-RichTM significantly increased redness (a*) and decreased lightness (L) of egg yolk. Yolk fatty-acid oxidation, as measured by thiobarbituric acid reactive substances (TBARS), was not affected by treatments in eggs stored up to 30 d at 4°C. Based on these data, adding All-G-RichTM in layer diets can produce DHA-enriched eggs with no negative impact on egg quality.

Organic egg production. II: The quality of organic eggs is influenced by hen genotype, diet and forage material analyzed by physical parameters, functional properties and sensory evaluation

The purpose of the study was to determine, how the dietary nutrients available in organic egg production, and especially how the obligatory forage material in relation to two different hen genotypes affects the quality of organic eggs evaluated by physical, functional and sensory properties. The experimental treatments were subjected to a total of 1200 hens, which were of two hen genotypes, representing a high egg yielding hybrid; Lohmann Silver (LS), and a dual-purpose hen genotype; New Hampshire (NH). They were fed three experimental feed diets (A, B and C), which were intended to differ in protein contents, hence methionine contents. Protein content of diets A, B and C were on average 203, 199, and 182g/kg dry matter, respectively, and methionine content were on average 3.9, 3.1, and 3.0g/kg dry matter, respectively. Furthermore, two forage material treatments were supplied (maize silage+carrots and alfalfa silage), altogether distributed in a complete randomized design with 4 replicate pens each of 25 hens. Each replicate pen had a separate house and outdoor hen yard of 4m2/hen. Eight times during the experimental period, from 22 to 41 weeks of age, eggs were collected for analysis of egg weight, egg dimensions, shell strength, egg yolk colour, carotenoid content of yolk, albumen pH, albumen DM, and albumen gel textural properties. Twice during the study, boiled eggs were evaluated for sensory properties. The results showed the hen genotype significantly influenced all analyzed egg quality parameters. Furthermore, the nutrient content of the diets significantly affected the egg weight and dimension, the shell fracture force, egg yolk colour, and carotenoid content. The forage material type also affected the egg quality. Feeding the alfalfa silage resulted in eggs of higher weight, no effect on shell quality, egg yolk colours of higher darkness, redness and yellowness, and a higher content of pigmenting carotenoids, but lower content of carotenes (α- and β-). No overall sensory differences of eggs from hens fed the two forage materials appeared, although some interaction effects were seen and are discussed.In conclusion, the egg quality in organic egg production is highly affected by the hen genotype, while further influence of the diet and forage material on the egg quality depends on the specific nutrients and compositions hereof.

Effects of recombinant lycopene dietary supplement on the egg quality and blood characteristics of laying quails

This study was conducted to determine the effect of dietary supplement of bacterial lycopene (BL) produced by Escherichia coli on the egg quality and blood characteristics of laying quails. The antioxidant activity measurement showed that BL exhibited 100% 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity at a concentration of 4.65μg/ml, which was more effective than butylated hydroxytoluene (BHT) and commercial lycopene (CL). Moreover, seven dietary groups of laying quails consisting of 10 100-day-old quails (Coturnix coturnix japonica) each were fed with the basal diet supplemented with BL, CL or canthaxanthin (CA) for 4 weeks. Consequently, the triglyceride content of yolk was significantly lower in the group with BL and CL supplement. The serum malondialdehyde (MDA) level of the BL- and CA-supplemented groups at 18mg/kg was lower than the control group. In conclusion, BL has a high antioxidant activity and is promising as a feed additive in the diet of laying quails.

Novel insights into relationships between egg corticosterone and timing of breeding revealed by LC‐MS/MS

Inter‐ and intra‐clutch variation in egg corticosterone (CORT), the major glucocorticoid in birds, may provide insights into how maternal stress levels vary with the timing of breeding and with laying order. Common analytical methods (e.g. immunoassays), however, suffer from cross‐reaction with other steroids, leading to potential overestimation of CORT concentrations which can obscure true hormone–environment relationships and complicate among‐study comparisons. We here apply a new LC‐MS/MS technique, which has recently been shown to avoid the problem of cross‐reactivity due to its high specificity, to quantify CORT concentrations in yolk and albumen in clutches of lesser black‐backed gulls Larus fuscus. We found that CORT concentration exhibited a previously unreported U‐shaped relationship with time of breeding, which we explain as a potential interplay of two forces exerting extra strain on the early and late breeders. Furthermore, results showed an increase in CORT with laying order indicating the energetic expense of egg production. The levels of CORT assessed in this study were significantly lower than those previously reported in studies using immunoassays for CORT analysis. This supports the fact that incorporating chromatography effectively reduces overestimation of CORT due to cross‐reactivity with other steroid hormones, particularly in egg yolk.

Effect of high stocking density on performance, egg quality, and plasma and yolk antioxidant capacity in laying hens supplemented with organic chromium and vitamin C

This study was conducted to investigate the effects of dietary supplementation of chromium–methionine (CrMet) and vitamin C on performance, egg quality measurements, and plasma antioxidant capacity in laying hens subjected to high stocking density. A total of 360 Hy-Line W-36 laying hens, 26wk of age, were used in a 2×2×3 factorial arrangement of treatments consisting of 2 cage densities [5 or 7 hens/cage (40×45cm2)], 2 supplemental vitamin C levels (0 and 500mg/kg as l-ascorbic acid), and 3 supplemental Cr levels (0, 500, and 1000μg/kg as CrMet) with 5 replicate cages per treatment. The hens were kept in wire-floor cages in an environmentally-controlled room. After a 2-wk adaptation, the 70-d study was initiated and it was divided into two 35-d periods (28–33 and 33–38wk of age). Results showed that although subjecting hens to high stocking density had no effect on egg production percentage during 28–33wk of age, it decreased (P=0.031) during the 33–38wk of age, resulting in a marked reduction (P=0.038) in egg mass. Dietary Cr supplementation (500 and 1000μg/kg) increased (P<0.01) egg production and egg mass during both 35-d periods, and improved (P=0.005) feed conversion ratio (FCR) during the first 35-d period. There was a stocking density×vitamin C interaction (P=0.018) for FCR values during the first 35-d period, so that supplemental vitamin C improved FCR to a greater extent in high stocking density-challenged hens. Dietary CrMet supplementation (500 and 1000μg/kg) increased (P=0.001) feed intake during the second 35-d period. Shell thickness was greater (P=0.015) in hens under high stocking density challenge during the second 35-d period. Subjecting hens to high stocking density decreased (P=0.007) plasma vitamin C concentration, while plasma vitamin C level was increased (P<0.05) as the result of dietary supplementation of vitamin C. Dietary supplementation of CrMet (500 and 1000μg/kg) increased plasma vitamin C level only in high stocking density-challenged hens, resulting in a stocking density×Cr interaction (P=0.039). Although high stocking density increased (P<0.05) plasma and yolk concentrations of malondialdehyde (MDA), supplemental vitamin C decreased (P<0.05) plasma and yolk MDA contents. Similarly, dietary inclusion of CrMet (500 and 1000μg/kg) decreased (P=0.046) plasma MDA level. The present findings indicate that dietary CrMet supplementation could increase antioxidant capacity in stressed hens, which improve production performance of laying hens.