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At least 1,405 records · Page 78Linked to original sources
PubMed1987

Regional differences in shell conductance and pore density of avian eggs.

Minidesiccators were attached to the middle and to the blunt and pointed ends of avian eggs of six different species and from their mass change over time the regional shell gas conductance was determined. Later the pore density and shell thickness of these areas were measured. All species showed a decline in regional shell conductance and pore density from the blunt end to the pointed end. With the blunt end over the air cell as a reference point, the regional conductance of the middle and the pointed end declined to 88 and 63%, while pore density fell to 81 and 63%, respectively. The six species represent four orders of birds, and the results suggest that differences in regional conductance may be a relatively common characteristic of bird eggs, that differences in regional pore conductance are proportional to the pore density, and that therefore the conductance of individual pores in any one species is relatively constant.

Animals↗
PubMed2003

Chemical composition of chicken eggshell and shell membranes.

This study was undertaken to determine the occurrence of uronic acid in chicken eggshell membranes and to compare chemical compositions among the inner and outer eggshell membranes and the organic matter of eggshell. We report here for the first time the occurrence of uronic acid in chicken eggshell membranes. Uronic acid concentrations were similar (P > 0.05) between the inner shell membrane and outer shell membrane but approximately fivefold higher (P < 0.05) in the organic matter of eggshell. Sialic acid concentrations were the highest (P < 0.05) in the organic matter of eggshell and higher (P < 0.05) in the inner than in the outer shell membrane. Nitrogen concentrations were the lowest (P < 0.05) in the organic matter of eggshell but relatively constant between the two shell membranes. Amino acid analysis showed that the contents of glycine and alanine were higher (P < 0.05) and those of proline and hydroxyproline were lower (P < 0.05) in the organic matter of eggshell compared to shell membranes.

Alanine↗
PubMedDate not supplied

Egg production drops in breeder turkeys associated with western equine encephalitis virus infection.

Egg production drops associated with western equine encephalitis (WEE) virus infection occurred in three turkey breeder flocks in California during summer 1993 and again in one flock the following year. Egg production losses totaled 8.76%, 9.57%, 9.71%, and 10.12% and were accompanied by an increase in small white-shelled and shell-less eggs. The outbreaks coincided with peak WEE virus activity in the state on the basis of statistics compiled by the California Department of Health Services on seroconversion rates in sentinel chicken flocks. Paired serum samples taken 2-3 wk apart showed increased titers to WEE between acute and convalescent sera in turkeys from three affected flocks. Convalescent sera were not available for testing from the fourth flock. WEE virus was isolated from one breeder hen submitted to the diagnostic laboratory during the early stages of the outbreak.

Animal Husbandry↗
PubMed2006

Detection of Hong Kong 97-like H5N1 influenza viruses from eggs of Vietnamese waterfowl.

Three H5N1 influenza viruses were isolated from shell washes of duck and goose eggs confiscated from travelers coming from Vietnam. All eight gene segments of these viruses share high sequence identity with the H5N1 avian influenza viruses that caused outbreaks in poultry and humans in Hong Kong in 1997. Animal studies indicate that these isolated viruses are able to replicate in mouse lung and could be found in the organs of ducks without causing any clinical signs or death. However, the viruses are highly pathogenic for chickens. Although the source of these recently isolated Hong Kong 97-like H5N1 viruses is undetermined, their detection in the egg shell of duck and goose suggests that this particular genotype of H5N1 virus may have re-emerged in nature or may have been circulating continuously.

Animals↗
PubMed2001

Evaporative cooling of ventral regions of the skin in heat-stressed laying hens.

Laying hens held in battery cages in naturally ventilated poultry houses in hot countries usually develop hyperthermia, which adversely affects their performance. The present means of cooling alleviate to some degree, but cannot eliminate, the stress imposed by heat. A new approach to cooling of laying hens was developed, based on wetting the skin and promoting evaporation of water from the ventral regions of the bird. The type of plumage in the ventral regions and the exposed skin of the apteria enable more efficient wetting than is possible with dorsal cooling. A ventral cooling regime, comprising an initial period of frequent wettings followed by intermittent wetting for 10 s every 30 min was able to maintain normothermia of laying hens subjected to a 10-h period of heat exposure. Dorsal cooling was less efficient; body temperature and respiration rate were higher and skin temperatures were lower than in ventrally cooled hens. During 10 d of heat exposure, ventrally cooled hens maintained egg weight and shell index (mg/cm2), whereas their food intake decreased moderately. In contrast, egg weight, shell index, and food intake all decreased markedly in uncooled or dorsally cooled hens. Transient alterations in plasma concentrations of corticosterone, progesterone, and estradiol were noted in uncooled and dorsally cooled hens but not in ventrally cooled hens. Results indicate that ventral cooling is an efficient method to alleviate heat stress in laying hens during summer. Successful implementation of ventral cooling in poultry houses will depend on optimal installation of sprinklers and on minimal wetting of manure.

Animals↗
PubMed1977

Residues of organochlorines and heavy metals in tissues and eggs of brown pelicans, 1969-73.

Shells of brown pelican (Pelecanus occidentalis) eggs collected in South Carolina from 1969 through 1973 were significantly thinner than shells of those collected before 1947. Residues of 10 organochlorine pollutants and 10 heavy metals were found in these eggs. Total organochlorine residues were apparently magnified 23 times from fish to pelican eggs, but interpretation of biomagnification was complicated by the migratory habits of both the pelicans and their chief prey fish. Residues of organochlorine pollutants and heavy metals were also found in tissues of brown pelicans. Dieldrin was probably involved in the death of a pelican that exhibited myocardial necrosis. Other pelicans died from gunshot wounds, various diseases, or unknown causes. From 1969 through 1973, there was a significant decline in residues of p-p'-DDE, p-p'-TDE, p-p'DDT, and dieldrin in eggs of the brown pelican in South Carolina, but the rate of decline was different for each pollutant. PCB's peaked in 1972 and then declined in 1973 to the lowest level in 5 years. In 1973, the first time in many years, South Carolina brown pelicans reproduced very well. The excellent reproductivity seemed related to lowered organochlorine residues and favorable tides, weather, and food supply.

Animals↗
PubMed1979

Egg drop syndrome, 1976 (EDS'76).

A description is given of the new clinical condition in fowl now known as EDS 76. This is characterised by the production of thin shelled, soft shelled and shell less eggs by apparently healthy birds. The effects on egg production are seen around 30 weeks of age and are seen either as an apparent fall in production or as a failure to obtain predicted production targets. Haemagglutinating viruses have been isolated from these flocks and evidence from experimental and field investigations suggest these are the aetiological agents of EDS 76. Biochemical and biological studies indicate that these viruses are duck adenoviruses. Epidemiological evidence suggests the virus is egg transmitted and that lateral spread between flocks is not important if care is taken whilst bleeding and vaccinating flocks. It is postulated that this virus may have been introduced into flocks by the use of a contaminated vaccine. Control in Northern Ireland has been by eradication of the virus from the basic breeding stock.

Adenoviridae↗
PubMedDate not supplied

Effects of avian infectious bronchitis virus (Arkansas strain) on vaccinated laying chickens.

Twenty-four-week-old white leghorn layers were inoculated subcutaneously with a killed Newcastle-infectious bronchitis (Massachusetts type) virus (MIBV) vaccine. The birds were challenged 194 days later intraocularly with Arkansas strain of infectious bronchitis virus (AIBV). The challenged hens laid significantly (P less than 0.005) fewer eggs than the unchallenged layers, and the eggs laid by the challenged groups weighed significantly less (P less than 0.001) than those laid by the unchallenged groups. Further, the internal quality (Haugh units) and shell quality of eggs laid by the challenged hens were significantly (P less than 0.005) inferior to the quality of eggs from unchallenged hens, and the challenged hens laid more soft-shelled, misshapen, and small-sized eggs than the unchallenged hens. The Arkansas serum hemagglutination-inhibition (AIBV-HI) titers of challenged birds increased continuously through 29 days post-challenge. The MIBV hemagglutination-inhibition (MIBV-HI) titers of killed-MIBV-vaccinated birds decreased during the same period. The study indicates that killed MIBV vaccine offered no protection to birds exposed to AIBV. The same vaccine was quite effective against a homologous (MIBV) virus challenge.

Animals↗