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The urodele egg-coat as the apparatus adapted for the internal fertilization.

Fertilization is a significant event for reproducing offspring. It is achieved under a species-specific environment, which influences the conditions to assure the successful fertilization in some cases. Several studies about the basic mechanism of fertilization suggest that the fertilization mechanism is modified among species to be suited for the fertilization environment. In amphibians, many anurans undergo external fertilization while most urodeles do internal fertilization. An amphibian egg is surrounded by egg-coats, which are composed of vitelline envelope and layered egg-jelly. They are significant as fields for the sperm-egg interaction at fertilization. The fertilization processes that take place in the egg-coats are supposed to be easily influenced by the fertilization environment, because they, especially egg-jelly, are exposed to the surroundings at fertilization. In the present article, we describe the fertilization system equipped in newt egg-coats. Newt sperm are stored in spermatheca that exists in cloaca of a female and directly inseminated on the surface of egg-jelly. Sperm motility and acrosome reaction are induced in the outermost portion of the egg-jelly. Motion of the moving sperm becomes vigorous in the egg-jelly and sperm are guided to vitelline envelope by the aid of egg-jelly structure. Most of the sperm passing through the egg-jelly, as the result, has been induced acrosome reaction and those sperm can bind to the vitelline envelope to contribute to the successful fertilization. This fertilization system has a distinct feature from the known system in species undergoing external fertilization. The feature of the system in the newt egg-jelly is discussed with the view to achieving the successful fertilization in the internal environment.

Adaptation, Physiological↗

[A Comparison Of The Efficiency Of The Three Egg Count Techniques]

Usually egg count technique has been employed to know the intensity of infestation of human intestinal helminths and to elucidate the effects of anthelmintics. Comparing the three egg count methods-Stoll's egg dilution method, Beaver's direct smear method and FHK counting board method-the authors reached the following results: 1) As the result of application of the three methods to 75 Ascaris egg positives and 95 Trichocephalus egg positives, in the case of Ascaris eggs, the egg detection rate was 99 per cent by Stoll's method, 97 per cent by Beaver's method and was lowest by FHK method at 79 %. Meanwhile, in Trichocephalus eggs, Stoll's method revealed 92 %, Beaver's method 95 %, and FHK method 95 %, there being no noticeable differences. 2) With regard to EPG, in counting Ascaris eggs, Stoll's method showed a value closest to the actual number of eggs, and the value revealed by FHK method was smaller than the actual number. 3) As the result of comparing the coefficiencies of variation of the three egg counting methods, both in Ascaris eggs and Trichocephalus eggs, the FHK method showed the smallest, followed by Stoll's method and Beaver's method.

Journal Article↗

Recent Demonstration Of Helminth Eggs And Larvae From Vegetable Cultivating Soil.

A survey on soil samples collected from the vegetable gardens and vinyl houses in the vicinity of Taegu was conducted for the discovery of helminth eggs and larvae from October 1981 to September 1982. The samples collected were examined utilizing the "Commonly Employed" and Kamiya's techniques. The details of comparative features of larval nematodes are taken from the handbook of parasitology by Matsubasyhi et al. (1965). The results were compared with the data obtained from soil samples collected at the same area by Lee(1976). Five kinds of helminth eggs, ascarid, hookworm, liver fluke, Trichostrongylidae, and whipworm and undetermined eggs were found. Of these, the incidence of ascarid eggs was found to be the highest, 70.5 per cent, followed by whipworm and hookworm eggs, 9.9 and 9.2 per cent, respectively. The average number of ascarid eggs per 100 grams of soil was higher in the vinyl houses, compared with the number in the vegetable gardens than in the vinyl houses. By contrast, the number of hookworm eggs was relatively high in the vegetable gardens. In the monthly incidences of helminth eggs, ascarid eggs were found every month, continuing fairly high incidences all the year round. However, hookworm eggs was found for 8 months from February and September, with low monthly incidences between 4.0 and 22.2 per cent, and Trichostrongylidae eggs were found for 6 months from April to September, with lower incidences than those of hookworm. Three kinds of larval nematodes, the filariform and rhabditoid larvae of hookworm, Trichostrongylidae, and undetermined larvae were found in the soil of farms, but the incidences of larvae were quite low. The average number of larvae per 100 grams of soil was 0.05. When the number of eggs per 100 grams of the soil in 1976 were compared with 1982, pronounced reduction of the number was encountered in all helminth eggs. However, the incidences and the average number of larvae per 100 grams of the soil were so low that it was impossible to compare the data between 1976 and 1982.

Journal Article↗

Comparative Morphology Of Eggs Of Heterophyids And Clonorchis Sinensis Causing Human Infections In Korea.

In order to provide some clues for differential diagnosis of trematode infections in fecal examination, the comparative morphology of eggs of 5 kinds of heterophyid flukes (Metagonimus yokogawai, Heterophyes heterophyes nocens, Heterophyopsis continua, Stellantchasmus falcatus and Pygidiopsis summa) and Clonorchis sinensis was studied. The eggs were obtained from distal portion of uteri of worms which were recovered from men after treatment. The characteristic shape and apperance of each kind of eggs were observed in detail under light microscope, and their length and width measured and compared one another. The results are as follows: Eggs of C. sinensis are elongated ovoidal in shape with attenuated anterior end, 25.3-33.2 (28.3 in average) micrometer long and 14.2-17.4(15.9) micrometer wide with length /width ratio of 1.60-2.00 (1.78). They differ from all heterophyid eggs in that they have prominent wrinkling (muskmelon pattern) at their shell surface. P. summa eggs are ovoid to pyriform in shape and characterized by the smallest size of all kinds examined, 19.8-22.9(21.6) micrometer long and 11.1-13.4 (12.1) micrometer wide and the ratio 1.63-1.99 (1.78). Eggs of S. falcatus are elongated ovoidal and most slender form, 25.3-29.2 (27.2) micrometer long and 11.1-13.4 (12.5) micrometer wide with the ratio of 2.00-2.57 (2.17). Eggs of M. yokogawai are ellipsoid to elliptical in shape with round both ends, 26.9-31.6 (28.5) micrometer long and 14.2-18.2 (16.8) micrometer wide with the ratio of 1.48-2.11(1.70). H. continua eggs are oval in shape, sometimes similar to M. yokogawai or H. h. nocens eggs, however, the relative breadth is broadest among all kinds, with maximum width at posterior half portion. They are 23.7-27.7 (25.0) micrometer long, 15.8-18.9 (16.4) micrometer wide with the ratio of 1.33-1.75 (1.53). Eggs of H. h. nocens are ellipsoid to ovoid in shape but sometimes more slender than M. yokogawai and have slightly pointed both ends. They are 23.7-29.2 (25.7) micrometer long, 14.2-15.8 (15.4) micrometer wide, and the ratio 1.50-2.06 (1.67). From the results, it is concluded that eggs of 5 kinds of heterophyids and C. sinensis can be morphologically differentiated one another, however, careful observation and measurement on sufficient number of eggs are needed.

Journal Article↗

The effect of twenty-four hour in vitro storage on sperm hydrolysis through the perivitelline layer of ovipositioned turkey eggs.

Counting the holes in the perivitelline layer surrounding the germinal disc of freshly laid eggs has been used as a means of assessing sperm attachment, their ability to undergo an acrosome reaction, and penetration of the ovum, all necessary steps in the process of fertilization. The objective of this study was to compare the number of holes in the perivitelline layer of eggs after insemination with fresh turkey semen or with semen stored in vitro for 24 h. Hens (n = 40) were inseminated weekly with either 100 x 10(6) or 10 x 10(6) liable sperm within 90 min of collection or 24 h after in vitro storage at 5 C. A minimum of 20 eggs per treatment group were evaluated for the number of holes in the perivitelline layer. Fertility and hatchability were determined for all other eggs. The number of holes in eggs from hens inseminated with 100 x 10(6) sperm was higher (P < 0.05) for fresh (119 +/- 23 holes per egg) vs stored (75 +/- 5 holes per egg) semen treatments over the 10-wk study period. Holes observed in the perivitelline layer of eggs from hens inseminated with 100 x 10(6) sperm were more numerous than those inseminated with 10 x 10(6) sperm (P < 0.05). The number of holes observed for fresh and stored 10 x 10(6) groups were 6 +/- 3 and 7 +/- 4 holes per egg, respectively. Fertility was higher for the eggs from hens inseminated with 100 x 10(6) sperm than for those from hens inseminated with 10 x 10(6) sperm (P < 0.05). Hatchability of fertile eggs was higher for the 100 x 10(6) dose eggs than for eggs that received the low dose but did not differ between fresh and stored treatments. This report shows that the number of sperm that hydrolyze through the perivitelline layer is reduced after in vitro storage of semen.

Acrosome↗

Persistence of egg recognition in the absence of cuckoo brood parasitism: pattern and mechanism.

Broad ecological shifts can render previously adaptive traits nonfunctional. It is an open question as to how and how quickly nonfunctional traits decay once the selective pressures that favored them are removed. The village weaverbird (Ploceus cucullatus) avoids brood parasitism by rejecting foreign eggs. African populations have evolved high levels of within-clutch uniformity as well as individual distinctiveness in egg color and spotting, a combination that facilitates identification of foreign eggs. In a companion study, I showed that these adaptations in egg appearance declined following introductions of weavers into habitats devoid of egg-mimicking brood parasites. Here, I use experimental parasitism in two ancestral and two introduced populations to test for changes in egg rejection behavior while controlling for changes in egg appearance. Introduced populations reject foreign eggs less frequently, but the ability of source and introduced populations to reject foreign eggs does not differ after controlling for the evolution of egg color and spotting. Therefore, egg rejection behavior in introduced populations of the village weaver has been compromised by changes in egg appearance, but there has been no significant decline in the birds' ability to recognize foreign eggs. This result reconciles earlier studies on this system and provides insights into the ways behavior can change over generations, especially in the context of recognition systems and the avoidance of brood parasitism.

Animals↗

[Calcium distribution in the egg cell, zygote and proembryo of lettuce (Lactuca sativa L.)].

Potassium antimonite precipitation was used to located calcium in the egg cells (before and after anthesis), zygotes and proembryos of lettuce (Lactuca sativa L.). A few calcium precipitates (ppts) were located in the small vacuoles of cytoplasm of egg cell at 3 d before anthesis, when egg cells just formed. Then the small vacuoles fused to form some bigger vacuoles in egg cell at 2d before anthesis. Calcium ppts increased evidently in the cytoplasm and nucleus of egg cells at this time. At 1d before anthesis, a biggest vacuole located at the micropyle end of the cell and its nucleus was pushed toward the chalazal end of the cell, which made an evident cellular polarity. The number of calcium ppts in the egg cell markedly decreased, suggesting that change of calcium distribution may be related to the development of egg cell. After anthesis and before fertilization, calcium ppts were still few in the egg cells, and most of them were accumulated in the nucleus, especially in the vacuoles of nucleolus. At 4h after anthesis, egg cell was fertilized and the wall at the chalazal end of egg cell was formed completely. Calcium ppts evidently increased again in egg cell, and some big ppts appeared in the karyoplasm of nucleus and abundant small ppts in the large vacuole. At 9h after anthesis, zygote completed its first division. Calcium ppts in the nucleus and cytoplasm of two-celled proembryo began to decrease, and only some ones accumulated in the vacuoles of nucleolus. At 18h after anthesis, zygote divided several times and became a multi-celled proembryo. Calcium ppts in the cells of proembryo ulteriorly diminished but there were many ppts on the surface of proembryo. The result indicates that calcium in egg cell, zygote and the cells of proembryo orderly changes its temporal and spatial position, which suggests that calcium may play a role during the development of egg cell and zygote.

Calcium↗

An ultraviolet-attenuated egg vaccine for swine ascariasis: parameters affecting the development of protective immunity.

Pigs inoculated with UV-irradiated Ascaris suum eggs developed immunity against challenge exposure with A suum infective eggs. Trials were conducted to determine the optimal conditions necessary to induce high levels of protective immunity and minimize liver lesions related to larval migration. Protective immunity was defined as the percentage of reduction in the recovery of larvae from the lungs of inoculated pigs, compared with controls, 7 days after challenge exposure with 5 X 10(3) or 10(4) infective eggs. Initial experiments showed that protective immunity was higher in pigs inoculated orally with UV-irradiated eggs than in those inoculated intraperitoneally. The highest level of protection (94%) was obtained by immunization with 5 oral inoculations of 10(4) eggs that had been UV-irradiated at total energy doses (ET) of 150, 100, 75, 75, and 75 mu W-min/cm2, respectively. A level of 83% protection was induced with as few as 2 oral inoculations of eggs irradiated at 150 and 75 ET, respectively. However, protection was reduced when pigs received eggs that were irradiated at and above 400 ET. The minimum number of irradiated eggs required to induce significant (P less than 0.05) protection was determined by feeding pigs 10(4), 10(3), or 10(2) eggs irradiated on 3 consecutive weeks at 150, 100, and 75 ET; the levels of protection induced were 94%, 89%, and 83%, respectively. Pigs inoculated with equal numbers of UV-irradiated eggs or normal eggs developed a similar level of protective immunity after challenge exposure. However, worms developing from the inocula were detected in the intestines of some of those pigs that had received normal eggs, but not in those pigs given UV-irradiated eggs.

Animals↗

Genetic and pharmacological analysis of neurotransmitters controlling egg laying in C. elegans.

We have investigated the neurotransmitters used to control egg-laying in C. elegans. Previous studies suggested that 5-HT released by the HSN motor neurons stimulates egg laying, and that tricyclic antidepressants potentiate egg laying by blocking reuptake of 5-HT by the HSN neurons. We report studies of the wild type and a mutant that lacks detectable 5-HT that suggest 5-HT is not required for egg-laying. Furthermore, we find that ACh is required for egg laying in response to 5-HT, suggesting that 5-HT is not sufficient to activate egg laying. The dominant egl-2(n693) mutation, which causes animals to lay eggs in response to tricyclics but not 5-HT, also conflicts with the model for egg laying. Experiments in which the HSN neurons or 5-HT are removed from egl-2 animals indicate that the action of tricyclics cannot be explained by a block of 5-HT reuptake. We find that D2 family dopamine antagonists can also induce egg laying in egl-2(n693) mutants, and that dopamine inhibits egg laying in the wild type. These results suggest that dominant egl-2 mutations activate an inhibitory dopaminergic pathway that can be blocked by tricyclics and D2 antagonists. We also find that these drugs stimulate egg laying in mutants lacking 5-HT or the HSN neurons, consistent with a target on the egg-laying muscles. In contrast to tricyclics, fluoxetine and other selective 5-HT reuptake inhibitors appear to be specific for 5-HT reuptake in C. elegans egg laying.

Acetylcholine↗

Nondestructive prediction method for yolk:albumen ratio in chicken eggs by computer image analysis.

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.

Albumins↗

Effects of light intensity from photostimulation in four strains of commercial egg layers: 1. Ovarian morphology and carcass parameters.

We examined the effects of light intensity (LI) from photostimulation to 45 wk of age on egg production parameters and egg size characteristics and on ovarian and carcass morphology at sexual maturity and 45 wk of age in four layer strains. Floor housed pullets were raised in a light-tight facility from 1 d of age until housing in individually illuminated cages at 17 wk of age. Two white egg strains, ISA-White (ISA-W) and Shaver 2000 (S2000), and two brown egg strains, ISA-Brown (ISA-B) and Shaver 579 (S579), were used. Pullets were randomly assigned to a processing group that was killed at sexual maturity (first oviposition) (Group 1) or kept to 45 wk (Group 2). Birds were photostimulated at 18 wk of age using a LI of 1, 5, 50, or 500 lx (4 x 4 factorial design). One bird from Group 1 and one from Group 2 were caged together in individually lit cages (one brown and one white egg layer). Carcass and ovarian morphology data were examined as related to Strain, LI, or the interaction of Strain and LI. The time from photostimulation to sexual maturity did not differ due to LI, but was shorter for brown egg strains (ISA-B = 19.9 d, S579 = 20.2 d) than for white egg strains (ISA-W = 26.6 d, S2000 = 28.1 d). Body weight at sexual maturity differed among all strains, with the white egg strains having the lowest BW. Ovary weight was the greatest in ISA-W birds, in which 8.0 large yellow follicles (LYF) were present compared to 6.8 in S2000 birds. The LI affected ovary development, as birds with the 1 lx exposure had lower ovary weights and fewer LYF than did 50 lx birds, suggesting that the 1 lx LI did not result in an adequate photostimulatory cueing of sexual maturation. The threshold LI for a complete morphological response to photostimulation in this study was 5 lx. Strain differences in BW observed at sexual maturity continued to 45 wk of age. Light intensity affected 45 wk BW, with 5 lx LI birds weighing 7.2 and 8.7% more than the 50 and 500 lx birds, respectively. On an absolute basis, brown egg stains carried significantly more breast muscle at 45 wk of age than did white egg strains. The fatpad was heavier on a relative basis for brown egg layers than white egg layers. The 1 lx hens had lower 45-wk ovary weights than did the other three LI treatments. These data support the conclusion that with the development of highly specific genetic strains, it is increasingly important to match the environmental management practices to a particular hen's genotype.

Animal Husbandry↗

Destruction of enteric bacteria in liquid egg with beta-propiolactone.

Liquid whole egg or egg white, inoculated with Escherichia coli 1485, Salmonella senftenberg ATCC 8400, or Salmonella typhimurium 84-I, was treated with concentrations of beta-propiolactone ranging from 0.05 to 0.3%. Egg white containing 1 x 10(3) to 1 x 10(6) cells of E. coli 1485 per ml was sterilized in 1 hr at 27 C by lactone concentrations of 0.2 and 0.3%. Egg white containing 1 x 10(5) cells of S. senftenberg ATCC 8400 per ml was sterilized in 12 hr at 10 C by 0.1% lactone and in 2 to 3 hr by 0.3% lactone at the same temperature. Liquid whole egg inoculated with 1 x 10(5) cells of either species of Salmonella was sterilized in 4 to 5 hr at 10 C with 0.2% lactone or in 2 to 3 hr by 0.3% lactone at this temperature. A mild heat treatment of either 15 min at 37 C or 1 min at 55 C markedly shortened the exposure times required for sterilization by beta-propiolactone at 10 C. After disinfection was complete, the lactone-treated liquid whole egg was reinoculated with low cell numbers of either species of Salmonella to determine the presence of residual lactone or toxic products. Liquid whole egg treated with 0.2% lactone would support the growth of salmonellae after 13 to 14 hr at 10 C. A heat treatment of 45 min at 37 C or 10 min at 55 C immediately after addition of 0.2% lactone allowed growth of the salmonellae in the lactone-treated liquid whole egg. No evidence of residual toxicity from the lactone treatment was found. The amount of lactone needed to prevent the outgrowth of low cell numbers of either strain of Salmonella in liquid whole egg was quantitated. Liquid whole egg containing 0.06 to 0.07% lactone would not support salmonellae growth from inocula of 1 to 10 cells per ml of egg. Lactone concentrations above 0.08% prevented outgrowth of salmonellae inocula of 10 to 200 cells per ml of liquid whole egg.

Anti-Infective Agents, Local↗

Evaluation of occupational asthma from airborne egg protein exposure in multiple settings.

We previously reported IgE-mediated occupational asthma among workers exposed to airborne egg protein at a plant that produces liquid and dried powdered egg products. To demonstrate that our original observations are generalizable to other facilities that process eggs, and to estimate the prevalence of IgE-mediated occupational asthma among egg-exposed workers, we conducted surveys at two additional plants. We administered a questionnaire to 188 employees to identify workers with symptoms suggestive of occupational asthma. We further evaluated 88 workers with and without symptoms by a clinical examination by a physician blinded to results of other tests, serial peak expiratory flow rate (PEFR) determinations every three hours while awake for one week, and skin prick tests and serum specific IgE levels to extracts of factory egg products, commercial egg test reagents, and egg white protein fractions. Fourteen workers had work-related asthmalike symptoms by questionnaire, a physician diagnosis of occupational asthma, and evidence of IgE-mediated sensitization to one or more egg proteins. Workers exposed exclusively to liquid egg aerosol, as well as workers exposed primarily to dried airborne egg protein, developed occupational asthma. This study replicated our original observations and demonstrated that workers in all areas of liquid and powdered egg production are at risk of developing occupational asthma from exposure to airborne egg proteins.

Air Pollutants, Occupational↗

Gas chromatographic analysis of shell membrane amino acids from hard-shelled, soft-shelled, and shell-less eggs.

The amino acid composition of shell membranes from hard-shelled (HS), soft-shelled (SS), and shell-less (SL) eggs produced by 62-wk-old hens was analyzed by gas chromatography using N-acetyl n-propyl ester derivatives. This technique succeeded in identifying tryptophane and ornithine as shell membrane components. There were no significant differences in the concentrations of any of the 17 amino acids analyzed among HS and SS eggs, HS and SL eggs, or SS and SL eggs. Stepwise discriminant analysis of the amino acid ratios correctly classified all of the amino acid chromatograms of shell membranes from HS/SL and SS/SL egg pairs, and 92.9% of the HS/SS and 90.0% of the HS/SS/SL amino acid chromatograms were classified correctly (F = 1.0). Higher F values reduced the percentage of correct classifications to 75.0%, 85.0%, and 67.5% (F = 2.0) for the HS/SL, SS/SL, and HS/SS/SL egg groups, respectively, and to 78.6% (F = 3.0) for the HS/SS egg group. Stepwise discriminant analysis also identified specific amino acid ratios that were most efficient at classifying the amino acid chromatograms according to shell type. This process identified three amino acid ratios for the HS/SS egg group (F = 3.0), two ratios for the HS/SL egg group, four ratios for the SS/SL egg group, and four ratios for the HS/SS/SL egg group (F = 2.0). Based on the number of times they appeared as efficient discriminating variables at higher F values, alanine, proline, and isoleucine seemed to be the most important amino acids for correctly classifying shell membranes by egg type.

Amino Acids↗

Production and egg-quality responses of White Leghorn layers to anticoccidial agents.

Two studies were conducted to determine the effects of anticoccidial agents on the production and reproduction of White Leghorns. In Experiment 1, nicarbazin (NCZ) was fed at 0, 20, 50, and 100 ppm. Hen-day egg production, egg weight, the egg-yolk DNC (4-4'-dinitrocarbanilide) level, and egg-yolk mottling were affected by the treatments. When response was evidenced, the relationship between those variables and the level of NCZ was basically linear. Decreased egg production occurred from Days 5 and 6 of the treatment through Days 1 and 2 of withdrawal. On Days 9 and 10 of treatment, the control hens peaked at 92% hen-day production, while hens fed 20, 50, and 100 ppm of NCZ peaked late--at 90, 82, and 80%, respectively. Compared to the controls, egg weight was reduced linearly as the level of dietary NCZ increased. The egg-yolk DNC level increased from Days 3 and 4 of treatment through Days 9 and 10 of withdrawal. Egg yolk mottling generally increased along with the level and duration of feeding NCZ. If the NCZ was mistakenly fed to White Leghorn layers, ill effects would be alleviated within 10 days after drug withdrawal. In Experiment 2, halofuginone (3 ppm), maduramicin (5 ppm), monensin (100 ppm), narasin (70 ppm), nicarbazin (125 ppm), robenidine (33 ppm), and salinomycin (60 ppm) were fed to White Leghorn hens at the levels specified in parentheses. Nicarbazin reduced egg production, depressed egg weight, reduced shell thickness, and caused egg-yolk mottling; but internal egg quality, as measured by Haugh Units, was unaffected. Halofuginone, maduramicin, monensin, narasin, robenidine, and salinomycin did not have a meaningful effect on the variables measured when fed to White Leghorn layers.

Animal Feed↗

Bacterial penetration into eggs washed with various chemicals and stored at different temperatures and times.

Eggs were washed with one of three commercial egg-washing chemicals, including a quaternary ammonium compound (QAC, pH 7.5), sodium carbonate (Na2CO3, pH 12), and sodium hypochlorite (NaOCl, 100 ppm, pH 7.5). One hundred fifty intact-shell eggs were washed at 43.3 degrees C with each of three chemicals. A control group was washed with tap water (H2O, pH 7.0). The washed eggs then were inoculated by immersion for 3 min into an aqueous suspension of Salmonella enteritidis at 10(4) colony-forming units/ml and dried for 30 min. The washed and inoculated eggs were stored at 4 degrees C or 23 degrees C, and bacterial penetration was checked at 0-, 7-, 14-, and 21-day intervals. The effects of egg-washing chemicals on microstructural changes of eggshell and postwash inoculation were examined using electron microscopy and conventional culture methods. Fifteen eggs were used in each sample. The results of microbial tests showed that both QAC and sodium hypochlorite treatments reduced bacterial penetration (less than 3.4% and 6.7%, respectively, on day 1 and 16.7% on day 21). The sodium carbonate treatment facilitated bacterial penetration during egg storage (less than 30% on day 1 and 76.7% on day 21). The eggs washed with tap water had a bacterial penetration rate of less than 6.7% on day 1 and 20% on day 21. As the storage intervals increased to 21 days, the bacterial penetration rate increased. Different storage temperatures (4 degrees C and 23 degrees C) did not cause a significant difference in bacterial penetration rates within 21-day interval. The results of electron microscopy showed that QAC and sodium hypochlorite at 100 ppm resulted in microbiologically clean eggs and did not destroy eggshell surfaces, which protected the eggs against future bacterial recontamination. The alkaline sodium carbonate produced visually clean eggs but altered the eggshell surface, which allowed bacterial recontamination.

Animals↗

Influence of protein concentration, amino acid supplementation, and daily time to access to high- or low-protein diets on egg weight and components in laying hens.

Feeding a 13% CP diet based on corn and soybean meal and supplemented with methionine to laying hens results in reduced egg weight in comparison with hens fed a corn and soybean meal methionine-supplemented diet containing 16% CP. An experiment was conducted to determine whether the egg weight reduction could be eliminated by supplementing the low-protein diet with additional lysine, methionine, and tryptophan or by adding glycine and glutamic acid to increase the amino nitrogen to a level equivalent to 16% CP. The influence of the dietary treatments on the weight of the major egg components was also determined. In a second experiment, the influence of time of day of feeding the 13 or 16% CP diets on egg weight and egg components was determined. Adding additional amino nitrogen in the form of glycine and glutamic acid or increasing the levels of lysine, methionine, or tryptophan individually or in combination failed to prevent the depression in egg weight of hens fed the lower protein diet. Measurement of egg components demonstrated that the reduction in egg weight was primarily associated with a reduction in albumen content of the egg. Feeding a high-protein diet from 1400 to 0800 h and a low-protein diet from 0800 to 1400 h resulted in egg weight equivalent to that from hens continuously fed the high-protein diet. The lower weight of the albumen in eggs from hens fed a 13% CP diet may be due to a lower availability of amino acids for protein synthesis during the 3- to 4-h period when the ovum is in the magnum.

Amino Acids↗

Quail egg yolk: a novel cryoprotectant for the freeze preservation of Poitou jackass sperm.

For many years, attempts have been made to establish a sperm bank for the Poitou jackass population which is threatened with extinction. Unfortunately, no cryopreservation technique has ever been described for spermatozoa of this species. In an attempt to find a suitable technique, we studied the relative effectiveness of chicken egg yolk and quail egg yolk in preserving the motility and characteristics of movement of Poitou jackass spermatozoa during the freezing-thawing process. Semen was diluted to 60 x 10(6) sperm/ml in a preservation medium containing 4% (v/v) glycerol with 0, 2, 5, 10, 15, or 20% (v/v) of chicken or quail egg yolk. The chemical composition of these two eggs was compared. Effects were assessed using an automated analyzer which measured curvilinear velocity (VCL), straight line velocity (VSL), and the velocity of the average path. Linearity was defined as VSL/VCL x 100. The amplitude of the lateral head displacement was also measured. It was found that after the freeze-thaw process, quail egg yolk improved the percentages of motile and progressively undulating spermatozoa and the movement characteristics compared with chicken egg yolk. The optimal concentration of quail egg yolk was 10%. The general composition of the two types of egg yolk were similar, but quail egg yolk contained significantly more phosphatidylcholine, less phosphatidylethanolamine, and a smaller ratio of polyunsaturated to saturated fatty acids than chicken egg yolk. The improvement of motility for frozen-thawed Poitou jackass spermatozoa using frozen-thawed quail egg yolk compared to chicken egg yolk may be due to the differences in composition of the two yolks.

Animals↗