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PubMedDate not supplied

Pathogenicity and distribution of egg-drop syndrome-1976 virus (JPA-1) in inoculated laying hens.

Rhode Island Red laying hens that lacked hemagglutination-inhibition antibody were inoculated orally with the JPA-1 strain of adenovirus isolated from a flock affected with egg-drop syndrome-1976 in Japan and observed for 80 days. Inoculated hens laid abnormal eggs, such as shell-less, soft-shelled, and cracked eggs and those with loss of pigmentation, from 8 days postinoculation (PI). Fifteen out of 16 hens laid abnormal eggs. Egg-production rte fell from 94% to 50% between 13 and 16 days PI. When the abnormal eggs were excluded, egg production was 17%; then it recoverd slowly, reaching 67% by the end of the experiment. The virus was recovered from various organs of inoculated hens from 3 to 7 days PI. Fluorescent antigens of the virus were observed in the epithelial cells and desquamated cells from the epithelium of the uterus and isthmus 10 and 14 days PI.

Adenoviridae Infections↗
PubMed2006

Non-invasive measurement of oxygen partial pressure, lateral diffusion and chorioallantoic blood flow under the avian eggshell.

We measured P(O2) under the shell of avian eggs indirectly, by sealing 0.05 mL glass tubes to the shell, sealing them with mercury and using an oxygen microelectrode to measure the contained gas that equilibrates with the gas in the shell membranes. This technique requires a smaller area of contact with the shell and a shorter equilibration period than established techniques, and allows measurements at several locations simultaneously and over a long period of time without endangering the embryo. P(O2) under the shell of chicken eggs decreased to 14.3 kPa on the day before hatching (day 19). P(O2) was unstable during late development and differences up to 3.1 kPa occurred transiently on opposite sides of the equator. By waxing the shell around sampling tubes, we estimated Krogh's coefficient for lateral oxygen diffusion in the shell membranes at 1.1 mmol cm(-1) d(-1) kPa(-1), a value about a third of a previous estimate. Sampling of gas under sufficiently large regions of waxed shell allowed indirect measurements of chorioallantoic venous P(O2), without affecting embryonic respiration. Venous P(O2) was 3.8 kPa on day 19. Assuming 14.3 kPa represents arterialized blood leaving the chorioallantois, it became possible to calculate the effective chorioallantoic blood flow rate, which was 3.5 mL min(-1) on day 19.

Animals↗
PubMed1996

Complex carbohydrates in shell precursor globules of the vitellarium and at the eggshell of Hymenolepis microstoma (Cestoda).

The vitellocytes of Hymenolepis microstoma contain protein globules as building material for the shell of egg cocoons. Complex carbohydrates were detected as an additive component, dispersed in the matrix of the shell globules. Similar glycans were found at newly formed shells, suggesting that these molecules are provided by the vitellocytes. The glycans remained associated with the surface of mature eggs. Carbohydrate residues, characterized using gold-labeled lectins, were N-acetylglucosamine, galactose, or the N-acetyllactosamine sequence of these residues and N-acetylgalactosamine, whereas glucose, mannose, and fucose were not demonstrable. The glycans scarcely stained with periodic acid-Schiff and, thus, seem to have few diols, and they did not bind cationic dye, indicating that they are not glycosaminoglycans. Since they occur in significant amounts, the glycans may have fundamental, as yet undetermined function(s) in the formation of the shells and/or interactions of the cocoons with the host.

Animals↗
PubMed2005

Production, egg quality, bone strength, claw length, and keel bone deformities of laying hens housed in furnished cages with different group sizes.

The effects of 3 different furnished cage systems (Aviplus, Eurovent 625a, Eurovent 625A) on 2 different laying hen strains [Lohmann Selected Leghorn (LSL), Lohmann Brown (LB)] were examined for the traits of production, egg quality, bone strength, claw length, and keel bone status. Two trials were carried out in which all hens received identical feeding and management. In brown hens, the traits egg production per average hen housed, cracked eggs, feed conversion, egg weight, and humerus breaking strength were significantly higher than in white hens. Furthermore, the claws of the brown hens were shorter than those of white hens. There were more dirty eggs, higher shell density, and fewer keel bone deformities in white hens than in brown hens. In the Aviplus system, egg production per average hen housed was higher than in the other systems, whereas shell thickness and density were lower. Humerus strength was also higher in the Aviplus than in the Eurovent 625a system, whereas there was no significant difference in tibia strength among the 3 systems. The shortest claws were found in the Aviplus system, and the fewest keel bone deformities occurred in the Eurovent 625a system. The study showed that the high standards of conventional cages for production and egg quality were met in furnished cages and that bone strength was significantly greater than in conventional cages. Claw shortening devices in furnished cages seemed satisfactory, because claws were generally short. However, the occurrence of keel bone deformities due to the intensive use of perches seemed to be a problem of furnished cages.

Animal Husbandry↗
PubMed1990

Egg and miracidium of Hirudinella ventricosa (Trematoda: Hirudinellidae).

It is reported for the first time that Hirudinella ventricosa releases eggs in strings, each string containing active spermatozoa and numerous oval, thick-shelled, translucent eggs measuring 40-42 x 28-30 microns. Each egg contained a fully developed miracidium with an anterior crown of spines.

Animals↗
PubMed1987

Shell conductance, daily water loss, and water content of Andean gull and Puna ibis eggs.

Characteristics of Andean gull (Larus serranus) and Puna ibis (Plegadis ridgwayi) eggs laid at 4,400 m in the Peruvian Andes were studied to determine how the conflicting requirements of maximizing O2 availability to the embryo while minimizing excessive losses of water vapor and CO2 have been met by avian populations breeding at high altitudes. Egg masses, linear dimensions, and surface areas of these montane eggs were similar to those of Heermann's gull (Larus heermanni) and glossy ibises (Plegadis falcinellus), but conductance to water vapor (GH2O, standardized to 760 torr) of Andean gull and Puna ibis eggs averaged 74.5% and 68.4%, respectively, of lowland values. The difference in GH2O of Andean gull eggs was caused primarily by a reduction in the number of pores per egg; both an increased shell thickness and a smaller number of pores reduced GH2O of Puna ibis eggs. Since the reduction of GH2O of montane eggs did not fully compensate for the change in barometric pressure (59% of sea level) and the increase in gaseous diffusion coefficients at 4,400 m, the "effective" conductance of the eggs at that altitude was greater than at sea level. Therefore, the eggs lost substantially more water during incubation than did lowland eggs. The modifications in eggshell characteristics of montane eggs may have resulted from selection to increase O2 availability to the embryo.

Altitude↗
PubMed1991

Reproductive performance of artificially inseminated hens receiving saline drinking water.

Laying hens were selected at random and placed in individual cages in a commercial type layer shed. One hundred hens received town water and one hundred received town water supplemented with 2 g NaCl/L. Half the hens on each water treatment were inseminated every 7 days with mixed semen collected from six cockerels of a commercial table egg strain maintained on town water. The remaining hens were inseminated with semen from six cockerels receiving town water supplemented with 2 g NaCl/L. Eggs were collected and stored at 12 C over a 7-day period before eggs with defective shells were identified and removed. All remaining eggs were incubated and candled at 7 and 18 days of incubation to detect infertile eggs and embryonic deaths. Data from six consecutive hatches were analyzed. The incidence of eggs with defective shells doubled in hens receiving the saline drinking water. These hens had a significantly (twofold) higher incidence of embryonic deaths and a significantly lower (13%) hatchability of fertile eggs. For every 100 eggs laid the numbers of settable eggs and chicks hatched were significantly reduced in hens receiving the saline drinking water. The saline water reduced the numbers hatched by 20% for every 100 eggs laid. The water treatment given to the cockerels had little effect on reproductive performance.

Animals↗
PubMed1983

Ahemeral light cycles and protein levels for older laying hens.

Variations in light:dark ratios and timing schedules of 26- and 28-hr ahemeral cycles were examined for their effects on shell quality and egg weight. In two experiments utilizing 2578 White Leghorn Laying hens, 16-week long ahemeral treatments were instituted abruptly late in the pullet laying season and again following a forced-molt production cycle. Ahemeral light-dark cycles of 28-hr length resulted in significantly heavier shell and egg weights as compared to 26-hr ahemeral cycles or the control 24-hr cycle. Ahemeral 26-hr cycles did not significantly increase egg weight compared to the 24-hr controls but did increase shell weight. Varying total light in 28-hr cycles from 20 to 10 hr with the light given in either one continuous period or interrupted by two intermediate dark periods and as either 18 or 16 hr of continuous light in the 26-hr cycles did not result in significant differences in shell or egg weight compared to the other treatments of the same cycle length. Rate of lay was lower for the hens given only 10 hr of interrupted light in a 28-hr cycle but was not otherwise affected by light treatment. Dietary protein levels of 15% (as compared to 17%) and 14% (as compared to 16 and 18%) consistently reduced egg weights (P less than .10 or less than .05) and tended to improve shell quality. These experiments further demonstrated the effectiveness of 26- and 28-hr ahemeral light-dark cycles in increasing shell weight as a method of extending the economic laying period of either older pullets or force-molted hens without a sacrifice in the number of eggs produced.

Age Factors↗
PubMed1997

Observations on the female reproductive cycle of captive giant tortoises (Geochelone spp.) using ultrasound scanning.

The reproductive activities of one adult female Galápagos tortoise (Geochelone nigra) and three adult female Aldabra tortoises (Geochelone gigantea) were monitored over 2 yr using ultrasound scanning. A nonrestraining technique of tactile stimulation was used for all examinations. Developing, preovulatory, and atretic ovarian follicles, as well as eggs at various stages of shell deposition, were identified and measured. In G. nigra, follicles became preovulatory at a diameter of 40-42 mm and eggs were laid 34-84 days (mean = 55.6, n = 5) after the thin-shelled eggs were first detected in the oviducts. Geochelone nigra was capable of retaining eggs, with the shell already formed, until the next breeding season. No eggs have been produced by G. gigantea during their stay in Zürich Zoo although follicles of 38-40 mm have been observed frequently in two animals.

Animals↗
PubMed1996

Egg Drop syndrome '76 in Bolivia.

Four outbreaks of Egg Drop Syndrome '76 (EDS '76) were diagnosed between April 1993 and July 1993 in the Santa Cruz Department of Bolivia, around the department capital Santa Cruz. Three outbreaks involved commercial laying birds and the fourth a broiler breeder unit. Clinical signs were typical of EDS '76 with decreases in egg production of up to 55% being recorded as well as the production of thin shelled and shell-less eggs. A total of 183 serum samples from the 4 farms were tested for the presence of antibodies to the EDS '76 virus using a haemagglutination inhibition test, with titres of 16 or above being considered as a positive result. Of 63 samples from groups of birds showing signs of EDS '76, 58 (92.1%) had positive titres, and 88 out of 90 samples (97.8%) from unaffected groups of birds had negative titres. Out of 30 samples from birds not yet in lay from the affected farms 28 (93.3%) had tires below 16. EDS '76 had not been reported in Bolivia prior to these outbreaks and vaccination was not practised. The most probable source of virus was from day old chicks imported from South American countries which had recorded outbreaks of EDS '76 before April 1993. The source of the virus, its spread and the control measures implemented in the Santa Cruz area are discussed.

Adenoviridae Infections↗
PubMed1992

Effects of age at lighting on reproduction of turkey hens.

Two experiments were conducted to evaluate age at photostimulation on subsequent reproductive performance of Large White turkey hens. All hens were exposed to short daylengths [8 h light (L):16 h dark (D)] for a minimum of 8 wk immediately prior to photostimulation with long day-lengths (16L:8D). Photostimulation started at either 24, 26, 28, or 30 wk of age during January and February (Experiment 1) or July and August (Experiment 2). Data were collected for body weight, time to onset of lay, egg production, and livability in both experiments. In addition, egg quality, broodiness, floor egg production, and poult weight data were obtained in Experiment 2. An inverse relationship occurred between initiation of egg production and the age at lighting up to 30 wk of age. However, peak egg production level and the number of eggs produced per hen during the first 20 wk of egg laying were similar among treatment groups in both experiments. The number of soft-shelled or shell-less eggs produced was also similar among treatment groups. Hens photostimulated at 30 wk of age in Experiment 2 laid the heaviest eggs throughout 20 wk of egg production. Poult weight was reduced when hens were photostimulated at 24 or 26 wk of age, but this only occurred in the first 11 wk of lay. Even though Large White hens responded to photostimulation at 24 wk of age, the results do not support advancing the age at photostimulation to 28 wk or earlier.

Aging↗
PubMed1993

Outbreak of gastroenteritis due to Salmonella enteritidis from locally produced grade A eggs, South Carolina.

Recent investigations of outbreaks of Salmonella enteritidis gastroenteritis among humans, especially in the northeastern United States, implicate grade A shell chicken eggs as the likely vehicle of transmission. In April 1991 we investigated an outbreak of S enteritidis infections after a wedding anniversary celebration in Beaufort, South Carolina. Sixty-eight percent of persons who ate a macaroni and cheese dish, but none of the 16 attendees who did not, became ill (P < .001). The chef used six grade A eggs in the macaroni and cheese and may have undercooked it. The egg supplier processed eggs exclusively from farms in South Carolina and North Carolina. This outbreak suggests that the epidemic of S enteritidis in flocks of laying hens the consequent threat of human infection has spread to the Carolinas.

Disease Outbreaks↗
PubMed1996

Eggshell conductance and other functional qualities of ostrich eggs.

Eggshell conductance was measured and eggshell conductance constants were calculated for eggs from ostriches. In addition, egg water, yolk, albumen, shell, and total solids were measured in an effort to determine the maternal investment of ostrich eggs. The results of the study suggest that the optimal incubator humidity for ostrich eggs is less than 25% to allow a 15% loss of initial egg mass during the 45-d incubation period. This low humidity does not preclude increasing humidity during the actual hatching process. In addition, incubation temperatures need to be adjusted to allow a longer development time for the embryo to attain an adequate level of maturity to survive the plateau stage in oxygen consumption or to prevent the use of limited energy of the yolk to survive the anoxia of tucking and internal pipping. The optimal incubation temperature of ostrich eggs appears to be between 36.1 and 36.9 C.

Animals↗