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The effect of the diet modification (soybean and lupine addition) on the content of protein and amino acids (AA) in eggs was studied. Both the sampling day and the diet influenced the total protein content. In albumen, the lowest protein content (10.6%) was noted after administering a diet containing 25% lupine; in the same egg the yolk contained the most proteins (16.7%). In the content of nonessential AA (NAA) in egg yolks, differences were noted only for cysteine, with its the highest content in the yolks of the control group. The stable content of essential yolk amino acids (EAA) was observed only for isoleucine, leucine, tryptophan and phenylalanine. The highest contents of EAA and NAA were recorded in the yolks of the control group (~47 and ~53 g/100 g of protein, respectively) and in the group with 25% additions of lupine (~42 and ~51 g/100 g of protein, respectively). AA with constant content in the tested albumens were methionine, tryptophan and alanine. The highest content of EAA (>~42 g/100 g of protein) and NAA (>~62 g/100 g of protein) were determined in albumen of eggs determined in the group with at least 20% additions of lupine. The highest content of EAA for humans delivered eggs from groups 4-6 (with the addition of soy into the diet ≤5%). The protein sources used in the hen diet significantly influenced the content of protein and individual AA in the produced eggs.

Amaranth (Amaranthus L.), like other pseudocereals as quinoa (Chenopodium quinoa Willd.), chia (Salvia hispanica L.) and buckwheat (Fagopyrum sp.), is a promising source of dietary protein. Depending on the subspecies and breeds of amaranth, the protein content in its grain is estimated from 13.1 to 21.5%, and its amino acid score varies over a significant range and can be limited. The aim of this study was to obtain a protein concentrate from amaranth (Amaranthus L.) grain of the Voronezh breed, enrich it with chicken egg protein, determine the amino acid score of the obtained protein module, and experimentally evaluate in vivo its true digestibility and biological value. Material and methods . The amaranth protein concentrate was obtained from grain according to the technological scheme, including its enzymatic treatment, alkaline extraction, acid precipitation of proteins, microfiltration and lyophilization. The amino acid composition and amino acid score of the concentrate were determined. The protein module was obtained by mixing amaranth protein concentrate and chicken egg protein in a weight ratio of 58:42. The true digestibility and biological value of the protein module has been determined in vivo. The experiment was carried out on 32 Wistar male rats divided into 2 groups (n=16 rats): control group 1 with a body weight of 118.7±3.1 g and experimental group 2 with a body weight of 119.5±3.0 g. Animals of groups 1 and 2 received diets in which egg protein and a protein module were used as a protein source, respectively. Within 15 days of the experiment, individual indicators of food intake and body weight gain of each animal were determined. From the 14th to the 15th day food intake was determined and feces were collected. The amount of nitrogen in the food and feces was determined for each rat using the Kjeldahl method. The true digestibility of the protein was determined according to obtained data. Results . The resulting amaranth protein concentrate contained 70.4±0.6% of protein, 17.0±1.0% fat, 9.8±0.8% carbohydrates, 1.8±0.2% ash, its moisture content was 1.4±0.1%. There were no significant differences in food intake and body weight gain between animals of both groups. The calculated value of the true digestibility of chicken egg protein was 98.8±0.1% for the control group 1, of the protein module was 99.0±0.1% for the experimental group 2, the differences between the groups were not significant. Conclusion . The results of amino acid analysis and the in vivo study of the true digestibility of the protein module (composition amaranth protein/chicken egg protein) indicate the absence of limitation relative to the amino acid scale of the "ideal" protein (FAO/WHO, 2007) and high true digestibility. The biological value of the protein module, calculated according to PDCAAS, is 99.0±0.1%, which confirms the prospects for its inclusion in specialized foods., Competing Interests: Authors declare no conflict of interest., (Copyright© GEOTAR-Media Publishing Group.)

Dietary supplementation of green tea powder (GTP) changes egg quality of hens, however, whether these changes affect incubation is still unknown. This study was to compare the proteomic difference of incubated eggs from hens with GTP supplemented or not. Huainan partridge chickens (1,080) at 35 wk of age were allocated into 2 groups, one group fed basal diet (CG) and one group fed basal diet plus 1% GTP (EG). After 4 wk feeding, artificially fertilized eggs were collected for yolk cholesterol determination and incubation. During incubation, 6 embryos from each group were randomly selected in each day for yolk protein extraction and quantification. Yolk cholesterol content was significantly lower, while the hatchability was significantly higher in EG than that of the CG group (P < 0.05). Yolk protein concentration at embryonic days (ED) of 0, 2, 6, and 13 showed significant changes and were selected for proteomic analysis by 2-dimensional gel electrophoresis combined with liquid chromatography-tandem mass spectrometry. Fifty-one differentially expressed (DE) protein spots were identified among different incubation stages between CG and EG group which were mainly classified into vitellogenin, immunoglobulin, and ovoinhibitor, and occupied 45.1, 23.5, and 15.7%, respectively, to the total DE proteins. Ovotransferrin, participated in extracellular sequestering of iron ion process, was significantly lower in EG group than that of the CG group (P < 0.05). Ig light chain precursor (Immunoglobulin) exhibited higher expression at ED6 in EG group as compared with that of the CG group, and was participated in immune response related processes. Ovoinhibitor, mainly involved in protease binding activity, showed lower abundance at ED13 in EG group as compared with that of the CG group. Vitellogenin-3, showed lower expression in EG group as compared with that of the CG group, was mainly participated in lipid transportation and localization according to GO enrichment. Chickens fed diet with GTP provided eggs more antioxidant ability that increased hatchability, indicated that GTP could be considered as additive in breeding layer., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

1. The aim of this experiment was to compare the effects of dietary supplementation of hesperidin, naringin and quercetin on laying hen performance, egg quality and egg yolk lipid and protein profiles. 2. A total of 96 Lohmann White laying hens weighing an average of 1500 g at 28 weeks of age were randomly assigned to a basal diet and the basal diet supplemented (0.5 g/kg) with either hesperidin, naringin or quercetin. Each treatment was replicated in 6 cages in an 8-week experimental period. Data were analysed using one-way analysis of variance. 3. None of the dietary flavonoids affected laying performance and eggshell quality. Hesperidin and quercetin supplementations decreased albumen and yolk indexes. 4. As compared to the control group, egg yolk cholesterol content decreased and egg yolk protein content increased in response to dietary hesperidin and quercetin supplementation. The mean egg yolk cholesterol (mg/g) and protein (g/100 g) contents were 10.08/14.28, 16.12/14.08, 14.75/15.04 and 15.15/14.85 for the control group and groups supplemented with naringin, hesperidin and quercetin, respectively. 5. Egg yolk lipid and protein profiles were variable. 6. In conclusion, dietary supplementation of hesperidin or quercetin could be used in the diets during the early laying period to reduce egg yolk cholesterol and increase egg yolk protein, which may be attractive to consumers.

A 35-day experiment was conducted to evaluate the effect of selenium-enriched probiotics (SP) on laying performance, egg quality, egg selenium (Se) content, and egg glutathione peroxidase (GPX) activity. Five hundred 58-week-old Rohman laying hens were randomly allotted to 5 dietary treatments of 100 each. Each treatment had 5 replicates, and each replicate had 5 cages with 4 hens per cage. The SP was supplemented to a corn-soybean-meal basal diet at 3 different levels that supplied total Se at 0.2, 0.5, and 1.0 mg/kg. The basal diet served as a blank control, while the basal diet with supplemental probiotics served as a probiotics control. The results showed that dietary SP supplementation not only increased (p < 0.05) the rate of egg laying, day egg weight, mean egg weight, egg Se content, and egg GPX activity but also decreased (p < 0.05) the feed:egg ratio and egg cholesterol content. The egg Se content was gradually increased (p < 0.05) along with the increasing level of dietary Se. The SP supplementation also slowed down (p < 0.05) the drop of Haugh units (HU) of eggs stored at room temperature. The egg GPX activity had a positive correlation (p < 0.01) with egg Se content and a negative correlation (p < 0.01) with egg HU drop. These results suggested that Se contents, GPX activity, and HU of eggs were affected by the dietary Se level, whereas the egg-laying performance and egg cholesterol content were affected by the dietary probiotics. It was concluded that this SP is an effective feed additive that combines the organic Se benefit for hen and human health with the probiotics benefit for laying hen production performance. It was also suggested that the eggs from hens fed this SP can serve as a nutraceutical food with high Se and low cholesterol contents for both healthy people and patients with hyperlipidemia, fatty liver, or cardiovascular disease.

1. The eggshell cuticle is the proteinaceous outermost layer of the eggshell which regulates water exchange and protects against entry of micro-organisms. In this study, we investigated the hypothesis that the cuticle may also reduce microbial contamination by providing a chemical defence. 2. Outer eggshell and cuticle protein was extracted from domestic chicken (Gallus gallus), duck (Anas platyrhynchos) and goose (Anser anser) eggs by HCl and urea treatment, respectively. Antimicrobial activity of the extracts against Gram-positive and Gram-negative bacteria was evaluated. 3. C-type lysozyme, ovotransferrin and ovocalyxin-32 were identified in all extracts by Western blotting. All extracts from all species demonstrated lysozyme enzymatic activity. Immobilised c-type lysozyme retained some enzymatic activity. Protein extracts demonstrated activity against Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis suggesting the action of antimicrobial proteins in addition to lysozyme. 4. The results suggest that the antimicrobial outer eggshell and cuticle proteins present in a number of avian species may be a mechanism which enhances avian reproductive success.

1. Egg white proteins from the eggs of domestic chicken (Gallus gallus), turkey (Meleagris gallopavo), duck (Anas platyrhynchos) and goose (Anser anser) were analysed in order to compare the antimicrobial activity of these products. 2. Albumen from each species was sampled and analysed by SDS-PAGE and Western blotting. Antimicrobial activity and lysozyme activity were measured. 3. Ovotransferrin and ovalbumin were identified in all species while c-type lysozyme was present in chicken, turkey and duck egg white samples, but not in goose. 4. Galliformes appear to possess albumens with greater antimicrobial activity than those of the Anseriformes. This can be attributed to higher concentrations of ovotransferrin and the broad acting c-type lysozyme.

Ovalbumin gene Y has been known as a member of the ovalbumin gene family since 1982, when its encoding gene was sequenced. In the present study, ovalbumin gene Y has been demonstrated as a new minor protein of hen egg white. This protein has been isolated by isoelectrofocalization and two-dimensional polyacrylamide gel electrophoresis and has been characterized using peptide mass fingerprinting. The concentration ratio of ovalbumin gene Y:ovalbumin is about 13:100. Unlike ovalbumin, ovalbumin gene Y is not phosphorylated, but like ovalbumin, this protein is glycosylated. Ovalbumin gene Y exists as a mixture of three molecular species, which differ in their isoelectric points. The polymorphism of this protein cannot be explained by various glycosylation levels.

The interaction of chicken spermatozoa with the inner perivitelline layer from different avian species in vitro during a 5 min co-incubation was measured as the number of points of hydrolysis produced per unit area of inner perivitelline layer. The average degree of interaction, as a proportion of that between chicken spermatozoa and their homologous inner perivitelline layer, was: equal to or greater than 100% within Galliformes (chicken, turkey, quail, pheasant, peafowl and guineafowl); 44% within Anseriformes (goose, duck); and less than 30% in Passeriformes (Zebra Finch) and Columbiformes (collared-dove). The homologue of the putative chicken sperm-binding proteins, chicken ZP1 and ZP3, were identified by Western blotting with anti-chicken ZP1/ZP3 antibody in the perivitelline layers of all species. The functional cross-reactivity between chicken spermatozoa and heterologous inner perivitelline layer appeared to be linked to known phylogenetic distance between the species, although it was not related to the relative affinity of the different ZP3 homologues for anti-chicken ZP3. This work demonstrates that sperm interaction with the egg investment does not represent such a stringent species-specific barrier in birds as it does in mammals and marine invertebrates. This may be a factor in the frequency of hybrid production in birds.

Upon photostimulation, restricted ovulator (RO) female chickens exhibit endogenous hyperlipidemia, develop atherosclerotic lesions, and generally fail to lay eggs. This phenotype results from a point mutation in the gene specifying the very low density lipoprotein receptor (VLDLR), whose protein product normally mediates the massive oocytic uptake of egg yolk precursors from the circulation. Taking advantage of the single base change in the mutant VLDLR allele, a PCR-based method for the rapid identification of RO chickens was developed at the Biocenter and University of Vienna, Austria. However, this procedure was incompletely validated because phenotypic data were not obtained and conventional progeny testing of sons and grandsons was not performed. Here, the assay validation was completed by providing plasma lipid concentrations, plasma very low density lipoprotein particle sizes, or egg production records of PCR-genotyped females and their brothers and sires to demonstrate that each bird's phenotypic traits substantiated their genotypic classification. Moreover, several methodological modifications resulted in improved chemical safety, speed, and cost of preparing and analyzing genomic DNA from chicken erythrocytes. Because the ovaries of mutant RO females generally contain numerous vitellogenic follicles in the absence of a functional oocyte plasma membrane VLDLR, the existence of an alternate system for the oocytic uptake of plasma very low density lipoprotein and vitellogenin is suggested, whereas a physiological explanation as to why some, but not all, mutant RO hens are able to ovulate and lay eggs is lacking.

The distribution of total 14C residues was studied in egg yolk and albumen after administration of either single or multiple oral dosages of [14C]sulfamethazine (SMZ). One day after a single dose of [14C]SMZ (121 mg of sulfamethazine, 2.42 x 10(7) dpm), the 14C residue concentration peaked in egg albumen and egg yolk with the concentration in the former >4-fold greater than in the latter. Three days postdose, the 14C residue concentration in the yolk was approximately 7-fold higher than in the egg albumen. A multiple dose of [14C]SMZ containing sulfamethazine mass equivalent of an average therapeutic dose (282 mg, 2.9 x 10(7) dpm) for chickens was also administered orally for six consecutive days to hens. A significantly reduced level of egg production was observed during the medication, and most of the hens stopped laying eggs after the last dose. The 14C residue concentrations peaked on the last day (sixth) of medication in egg albumen and yolk. The 14C residue concentrations were also measured in liver, muscle, blood, and plasma of chickens sacrificed at 1, 24, 48, and 72 h after the last dose. Highest concentrations of 14C residue were accumulated in liver followed by, in decreasing order, blood, plasma, and muscle.

[14C]sarafloxacin was orally administered to six laying hens for five consecutive days. Eggs were collected for 15 days after the initial drug treatment. Egg yolk and egg albumen were separated and assayed for total radioactive residues (TRR) using a combustion oxidizer and scintillation counting techniques. Radioactivity was detected in egg yolk and egg albumen on the second day of dosing and reached a maximum at 24 h after drug withdrawal. Thereafter, the sarafloxacin TRR levels in egg albumen declined rapidly and were undetectable 2 days after the last dose, whereas the levels in egg yolk declined at a much slower rate and were undetectable 7 days after drug withdrawal. In both the egg albumen and yolk, HPLC analysis indicated that the parent sarafloxacin was the major component.

The eggshell matrix is mainly composed of proteins that are thought to influence shell formation and calcification and, thus, modify the resulting properties of the shell. We investigated the potential of some of these proteins as biomarkers of eggshell quality by developing a competitive indirect ELISA for quantifying ovotransferrin, ovalbumin, and ovocleidin-17 in eggshell extract. Eggshell fragments were demineralized in acetic acid (20%) and freeze-dried. The micro-extraction yield was markedly increased (>50%) when Tween 20 was added to the subsequent extraction and dialysis milieus. Microplates were coated with ovotransferrin and ovalbumin in a 0.1M carbonate-bicarbonate buffer, but ovocleidin-17 was fixed with acetone (-20 C, 20 min). Optimal dilutions of the monoclonal (ovotransferrin) and polyclonal (ovalbumin and ovocleidin-17) antibodies were 1/3,000, 1/25,000 and 1/4,000, respectively. The inhibition curves were optimized by preincubating the antibodies and proteins overnight. The intraassay coefficient (<5%), parallelism of the standards and samples curves, and recovery (101%) were satisfactory for ovotransferrin. Measurements of ovalbumin were less precise because of higher interassay variation and differences between the slopes of standard and sample inhibition curves. Ovocleidin-17 assays showed similar slopes for standard and eggshell extracts. Although the total protein in soluble matrix extracts was not affected by age, the concentrations of these proteins were higher in eggshell extracts from older hens compared with those from young hens: 1.98x for ovotransferrin, 1.86x for ovalbumin, and 1.58x for ovocleidin-17. The quantification of specific eggshell matrix proteins in shell of differing quality is, therefore, a promising tool for analyzing the origin of eggshell faults and may provide useful information for breeding programs.

Developmental relationships between yolk, embryo body, and embryo liver compositions during incubation were determined in two trials. In Trial 1, embryo body moisture, fat, and CP contents and embryo liver moisture and fat contents were determined. In Trial 2, relative yolk weights, moisture, fat, and fatty acid contents, relative wet and dry embryo weights and moisture contents, and relative wet and dry liver weights and moisture contents were determined. In Trial 1, embryo moisture decreased sigmoidally between Days 6 and 21, whereas embryo fat increased between Days 12 and 21 of incubation; embryo CP displayed sequential fluctuations throughout incubation. However, an overall significant decrease in embryo CP occurred between Days 6 and 21. Liver fat content increased between Days 12 and 21, whereas liver moisture decreased through Day 18, with a subsequent increase by Day 21. In Trial 2, relative yolk weight and moisture content decreased, whereas percentage yolk lipid content increased between Days 6 and 15. Relative wet and dry embryo weights changed in a similar manner, with rapid increases between Days 12 and 18 of incubation. Embryo moisture and CP were negatively correlated to embryo fat content. Furthermore, relative embryo and liver DM were related to yolk palmitic acid concentration, whereas yolk oleic acid was correlated only with liver DM. In conclusion, embryos and their livers displayed differential accumulations of moisture and DM during incubation, and these differences exhibited distinctive associations with various yolk fatty acids.

There is interest in increasing the conjugated linoleic acid (CLA) content of foods because of purported benefits of CLA for human health. Two experiments were conducted to determine the influence of dietary CLA concentration on CLA content of eggs. In Experiment 1, diets containing 0, 0.5, 2.5, or 5.0% CLA were fed to 26-wk-old White Leghorn hens (Hy-Line W-77) for 29 d. No CLA was detected in the yolk lipids of hens fed the control diet. Concentration of CLA in the yolk lipids linearly increased as dietary CLA increased. The maximum concentrations of CLA in the yolk lipids of hens fed 0.5, 2.5, or 5.0% CLA occurred 11 d after the start of the experiment and were 0.82, 5.82, and 11.20% of the total fatty acids, respectively. Concurrent decreases were observed in concentrations of C18:1, C18:2, C18:3, C20:4, and C22:6. Rate of egg production, body weight gain, and feed intake were not affected by dietary CLA. Average weights of eggs and yolks were decreased for hens fed 5.0% CLA compared with other dietary treatments. In Experiment 2, 62-wk-old hens were fed diets containing 0 or 5.0% CLA. Maximum CLA concentration in the yolk lipids of hens fed 5.0% CLA was less (7.43%) than that observed in Experiment 1. Feeding 5.0% CLA decreased feed intake but did not affect rate of egg production, weight of eggs, albumens, or yolks, or body weight gain through 36 d. Results of these experiments show that eggs produced by hens fed 5.0% CLA will contain 310 to 365 mg of CLA per egg. Such eggs could provide a substantial amount of CLA source in human foods.

The purpose of this study was to develop a nondestructive prediction method for the yolk: albumen ratio by computer image analysis for candling inspection. Twenty-two to 49 eggs per line were randomly sampled from four chicken lines. After weighing the eggs, the eggs were illuminated by an overhead projector beam through a small hole in dark room. Video images were taken of the eggs from four directions, the eggs rotated each time by 90 degrees. The eggs were broken for measuring egg traits, including the yolk:albumen ratio. The average value obtained from four directions was used for statistical analysis. The ratio of the number of pixels of light and dark parts (light: dark ratio), and the CV of red (R), green (G), and blue (B) components for the whole egg and for light and dark parts of the egg were calculated and defined as image analysis traits. Correlation coefficients between the yolk: albumen ratio and CV of R and G components of the whole egg were significant (0.42 to 0.79) in all the lines. The determination coefficient of multiple regression of the yolk:albumen ratio on the CV of R and G components of the whole egg and the light:dark ratio was 0.83. Observed and predicted yolk:albumen ratios were classified into five levels. The ratio of zero difference between observed and predicted values was 76.1%, and the percentage of 0 to +/- 1 difference between observed and predicted values was 100.0%. The image analysis method accurately predicted the yolk:albumen ratio without breaking the egg.

The influence of supplemental Met levels ranging from 413 to 556 mg per hen per d (mg/HD) on liquid egg component yield, composition, and functionality was examined in mature layers (29 wk of age). Egg weight, component yield, solids, and CP content of albumen and yolk were determined. Texture profile analysis, feed ingredient functionality testing, and PAGE were conducted to determine whether increased egg total solids and CP content resulted in altered egg component functionality or electrophoretic protein banding pattern. Albumen component yield increased significantly on a mass basis at 507 and 556 mg/HD Met compared to 413 mg/HD Met. Yolk mass yield was significantly increased at 556 mg/HD Met compared to 413 mg/HD Met. Consumption above 413 mg/HD Met resulted in significantly increased albumen total solids and protein. Yolk solids were not significantly different; however, yolk CP was significantly increased at 507 and 556 mg/HD Met compared to 413 mg/HD Met. Albumen and yolk functionality at 413 and 507 g/HD Met were not significantly different in relation to cake volume or height. Emulsion separation at 120 min was significantly increased for 556 mg/HD Met compared to 413 and 507 g/HD Met. There were no significant differences in hardness or springiness of albumen and yolk gel plugs and electrophoretic protein banding patterns. Increased understanding of the influence of Met on liquid egg yield and composition may provide the egg producer with an effective and advantageous management technique for shell egg production specifically managed to maximize liquid egg product.

A study was conducted to determine the effect of egg size and the age and strain of hens on the content of egg solids. Eggs were obtained from commercial farms from four strains of hens with similar age groups and received diets formulated to contain the same dietary energy and protein levels across the strains within a farm. Eggs were collected on 2 different d when the flocks reached the average ages of 28, 55, 75, and 97 wk. The eggs collected form each farm were pooled and sorted by size. Each individual egg was used as a replicate for yolk:white ratio; however, five yolks, five whites, and five whole eggs from each strain at each age period were pooled, homogenized, and then used as a replicate to determine the solids contents of yolk, white, and whole eggs. The yolk:white ratio of eggs from 28-wk-old hens was the lowest, that from 55- and 78-wk-old hens was the highest, and that from 97-wk-old hens was intermediate; however, the solids content (percentage) of whole eggs increased with the age of the hens. The solids content of egg white was highest in eggs from 28-wk-old hens. The white solids content of extra large eggs was greater than that of medium eggs, and yolk solids increased with egg size; however, the solids of whole egg were not affected by egg size. The strain of hens had a significant effect on the solids of whole egg, white, and yolk; however, the strain effect on yolk:white ratio was not significant. The results showed that young (28-wk-old) and old birds (97-wk-old) produced eggs with low solids content and intermediate aged hens (55- to 78-wk-old) produced eggs with high solids content. Therefore, it may be more beneficial for egg producers and processors to use young (28-wk-old) and old birds (97-wk-old) for table egg production and birds of intermediate age (55- to 78-wk-old) for liquid egg production.

Currently, 24% of the total U.S. egg supply is consumed as liquid egg product (LEP). In addition to egg weight and size, the commercial value of LEP is a function of percentage solids. The influence of L-Lys on LEP, the texture profile analysis of heat formed albumen and yolk gel plugs, and yolk emulsion separations was examined in two experiments. In Experiment 1, 108 layer hens (42 wk of age) were fed three sorghum-soybean diets with Lys levels ranging from 677 to 1,613 mg per hen per d (mg/HD). In Experiment 2, 108 layer hens (23 wk of age) were fed four sorghum diets with Lys levels ranging from 638 to 1,165 mg/HD. In Experiment 1, Lys intake of 1,613 compared to 677 mg/HD significantly increased albumen weight, solids, and protein and egg weight. There were no significant differences in egg production, feed consumption, or yolk weight, protein, and solids. In Experiment 2, Lys intake of 1,165 mg/HD resulted in significantly lower feed consumption, nutrient intake, and egg production. Lysine intake of 1,062 compared to 638 mg/HD resulted in significantly greater albumen solids, protein, and hardness, and egg production. Lysine intake of 828 compared to 638 mg/HD resulted in significant increases in yolk weight, protein, hardness, and emulsion separations. Lysine intakes of 1,062 mg/HD resulted in most yolk parameters returning to levels observed at 638 mg/HD. There were no significant differences in egg weight or yolk solids. This increased understanding of the influence of L-Lys on LEP parameters offers economic benefit to liquid egg producers.

The differences in the hydrolytic activity of chicken spermatozoa towards the inner perivitelline layer in situ and when isolated from the ovum were investigated. Points of hydrolysis produced by chicken spermatozoa on the inner perivitelline layer of laid and freshly ovulated eggs were viewed as dark holes after staining with fluorescein-conjugated wheat-germ agglutinin. In laid eggs that had been fertilized in vivo, these holes appeared more frequently on the perivitelline layer overlying the blastodisc at the animal pole than on that overlying the vegetal pole. However, in an assay in which fragments of the inner perivitelline layer from freshly ovulated eggs were incubated with spermatozoa in vitro, points of hydrolysis appeared with similar frequency on the perivitelline layer from over the germinal disc at the animal pole or from that over the vegetal pole. No difference could be demonstrated in the electrophoretic profile of peptides extracted from the inner perivitelline layer at the animal or vegetal pole. The factor(s) responsible for either increased attraction of spermatozoa to, or for increased activity at, the perivitelline layer of the animal pole does not appear to be associated with the perivitelline layer itself.

The developmental maturity of hatchling birds varies greatly across the altricial-precocial continuum and these differences are related to the relative proportions of yolk and albumen in a species' egg. In general, the more precocial the chick the greater the proportion of yolk in its egg. Egg composition can also vary within species with unknown consequences for the developing embryo. The present research sought to determine the importance of egg composition to avian development by experimentally removing 1, 2, 4, 8, 12, or 16% of the albumen from eggs of domestic fowl (Gallus gallus). Experimental chicks were paired to control chicks whose eggs were matched on the basis of original mass and laid by the same female but no albumen was removed from their eggs prior to incubation. Decreased levels of albumen significantly decreased chick size at hatch. Experimental subjects, however, had similar growth to controls after 20 days of ad-lib access to food, although sex differences between pairs indicated that the growth of females may be affected differentially by albumen removal. Righting responses were retarded in experimental subjects for the 2 and 4% albumen-removal groups. Egg composition can have important consequences for chick survival simply by influencing body size at hatch and it is suggested that the practice of using overall egg size as a measure of egg "quality" needs to be broadened by considering what is inside the egg as well. In addition, the unique opportunity presented by using an avian model to assess directly the specific influences of protein (albumen) and of fat (yolk) on growth and behavioral development is explored.

Weights of internal organs and levels of digestive enzymes were obtained through the first 15 days posthatch for cockerels from three lines of chickens known to differ greatly in body weight. On Day 15 body weights from the fastest growing line were eight times greater than those from the slowest growing line. Differences among lines were found for weights at hatching and for growth patterns (both absolute and relative to body weight) of the vitelline residue, heart, lungs, liver, pancreas, crop, proventriculus, gizzard, and segments of the small intestine. Line differences were also evident for levels of trypsin, chymotrypsin, and amylase in the pancreas and contents of the small intestine. Ranking of lines for these traits varied with age. In all lines weights of the small intestine, liver, and pancreas increased relatively more than did total body weight during the 1st wk posthatch, after which the relationship reversed.

Comparative data collected over two years are presented which refute the popular press claims that blue-shelled eggs of Araucana chickens have higher protein levels and lower cholesterol levels than market eggs. These comparisons were made between the eggs from the strains of Araucanas and those of White Leghorns and Sex-links. None of the differences found between test groups in % protein/g. albumen and % protein/g. yolk were shown to be consistently related to any one test group type. However, all Araucana test groups were significantly (P less than .01) lower in their total egg protein content than either control group by from 2.8--6.5%. This lower total protein content was the result of a consistent increase in the yolk/albumen ratio of the Araucana eggs over the market eggs. The Araucana eggs were consistently higher in their cholesterol levels on a mg./g. yolk basis than either of the market eggs. These increased concentrattions ranged from 2.0--6.9%.

The amino acid sequence of apovitellenin I from hen egg yolk has been determined using both automatic and manual procedures; it comprises 82 residues. Hen apovitellenin shows considerable homology with emu apovitellenin I which contains 84 residues. Besides two deletions in the sequence, the hen protein differs in 28 positions from the emu protein; 26 of these positions may have arisen from single base changes. The changes are largely conservative ones, which suggest that the structure and function have been preserved despite extensive mutation.

A comparison of ovotransferrin types A and B showed that in starch gel electrophoresis both types consisted of one major and one minor component. Both types have a similar amino acid composition as do the fragments from each type. Starch gel electrophoresis shows that the cause of the difference in the electrophoretic mobilities between ovotransferrin types A and B lies in the C-terminal half of the molecule. No physiological difference was found between types A and B, both types donate iron to chicken embryo red cells at equal rate.