PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “eggshell”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1998

Effects of age at onset of production, light regime and dietary calcium on performance, eggshell traits, duodenal calbindin and cholecalciferol metabolism.

1. Rate of production and shell thickness (ST) decreased, while body weight (BW), egg weight (EW) and percentage breakage increased progressively with age. Shell weight (SW) increased until 8 to 13 months of age and then decreased. 2. Early onset of production resulted in lower BW and EW at the onset of production, and lower pooled averages of BW, EW, SW and ST, as compared with late or medial onset of production. In 4 out of 5 trials, early onset did not result in the production of more eggs during the laying period. 3. Early onset of production is associated with physiological Ca deficiency as indicated by increases in kidney-1-hydroxylase and duodenal calbindin in early layers as compared with late layers. Early layers exhibited a more severe reduction in shell quality as the result of Ca deficiency as compared with late layers. 4. Feeding pullets with a prelaying diet containing 3.9% Ca did not affect unequivocally the performance or shell quality during the whole productive period, whether the birds started to lay early or late. The dietary treatment did not cause renal damage, as indicated by morphological examination and by plasma calcium and uric acid concentration.

Age Factors↗
PubMed1990

Genetic analysis of two female-sterile loci affecting eggshell integrity and embryonic pattern formation in Drosophila melanogaster.

We have analyzed female-sterile mutations at the X-linked loci fs(1)Nas and fs(1)ph which show allele-specific effects on egg shell structure and embryonic pattern formation. The majority of mutant alleles at both loci lead to a collapsed egg phenotype. The maternal effect lethal phenotype is characterized by cuticle defects resembling those found in three autosomal mutants of the terminal class. We have analyzed the complementation behavior of various heteroallelic combinations at both loci and show that one such combination at the fs(1)Nas locus is capable of restoring normal fertility. We have investigated possible interactions between fs(1)Nas and fs(1)ph and also between the terminal allele of fs(1)Nas and various maternal effect mutations altering the anteroposterior polarity of embryos. We have isolated one new allele of fs(1)Nas which combines the locus-typical phenotypic features with novel cuticle phenotypes. Our results suggest that the products of fs(1)Nas and fs(1)ph are required for the stability of the vitelline membrane and are also involved in a morphogenetic pathway necessary for the correct differentiation of the terminal regions of the embryo. Possible mechanisms to account for the association of these two functions are discussed.

Alleles↗
PubMed2001

Long-term effects of feeding flaxseed-based diets. 1. Egg production parameters, components, and eggshell quality in two strains of laying hens.

We used a split-plot design of five diets: control (corn-soy) with 3.8% Ca, 10% flaxseed with 3.8% Ca, 10% flaxseed with 4.5% Ca, 10% flaxseed with 3.8% Ca and 22,000 IU vitamin D3/kg, and 10% flaxseed with 4.5% Ca and 22,000 IU vitamin D3/kg, and two strains of birds, DeKalb Delta (DD) and Hy-Line W-36 (HL), to evaluate long-term effects of flaxseed supplementation on egg production parameters. Each of the five treatments was randomly assigned and replicated six times with five hens per replicate pen from 21 to 57 wk of age. Phase I was from 21 to 39 wk, Phase II was from 40 to 48 wk, and Phase III was from 49 to 57 wk. Feed consumption was significantly (P < 0.04) greater for the hens fed 10% flaxseed diets (100.9 g) when compared to the corn-soy controls (99.3 g). Overall average egg production (P < 0.05) was 87.8, 87.1, 86.0, 87.1, 84.8, for diets 1, 2, 3, 4, and 5, respectively. Average hen weights during the study were significantly lower for the flaxseed-fed hens (1.559 kg) compared to the controls (1.616 kg). Egg weight was significantly affected by diet during Phase III with heavier eggs from flaxseed fed hens (62.6 g) compared to controls (61.44 g), but overall egg weight was not significantly affected. Average egg mass was not significantly affected by dietary treatments, but DD hens had a decrease in egg mass with Ca supplementation (Diet 2 vs. Diet 3), whereas HL egg mass increased with Ca supplementation. Percentage albumen had a significant strain effect and strain by diet interactions. Overall, significantly less albumen (P < 0.001) was produced by HL (59.4%) compared to DD (61.3%). Supplemental Ca increased albumen percentage in DD (interaction effect P < 0.03) and decreased albumen percentage in the HL strain. Flaxseed supplementation significantly increased albumen percentage (P < 0.02) when compared to the corn-soy control, 60.5 and 59.9%, respectively. An interaction effect (P < 0.01) was noted for percentage wet yolk, in which increasing Ca decreased wet yolk percentage in DD but increased yolk percentage in HL. Wet yolk percentage was also significantly (P < 0.001) less in DD (25.0%) when compared to HL (26.9%). Addition of flaxseed decreased yolk percent when compared to controls (P < 0.03) during Phase II. Ca supplementation significantly (P < 0.03) increased yolk solids in both strains. Grams of yolk solids per egg were affected by flaxseed supplementation (P < 0.06). Flaxseed eggs contained 7.18 g per egg yolk solids compared to 7.3 g in corn-soy control group. Wet shell percentage was significantly lower in the flaxseed diets (12.4%) when compared to the controls (12.6%). Addition of flaxseed to the diet of laying hens did not have any adverse effects on egg production parameters, but flaxseed supplementation can significantly alter weight of yolk solids and yolk and albumen percentages.

Age Factors↗
PubMed2003

Effects of reducing dietary protein, methionine, choline, folic acid, and vitamin B12 during the late stages of the egg production cycle on performance and eggshell quality.

A series of four experiments was conducted to determine whether-shell quality during the late stages of egg production can be improved by using diets that are effective in reducing egg size. The experiments involved dietary manipulation of protein, methionine, choline, folic acid, and vitamin B12. In experiment 1, reducing dietary protein in combination of reducing the dietary methionine and choline or this diet without supplemental folic acid and vitamin B12 resulted in reduced egg weight and improved shell quality. However, egg production also was drastically reduced. In experiment 2, reducing the dietary level of methionine, without adding supplemental choline, folic acid, and vitamin B12 reduced egg size and improved shell quality, but egg production was reduced as well. In this experiment reducing the dietary methionine without supplemental folic acid and vitamin B12 reduced egg size and improved shell quality with no adverse effect on egg production. In experiment 3, reducing the dietary level of methionine and choline or reducing the dietary level of choline, folic acid, and vitamin B12 reduced egg size and improved shell quality without adverse effects on egg production. On the other hand, reducing dietary methionine, folic acid, vitamin B12, and supplemental choline reduced egg weight and improved shell quality but lowered egg production. In experiment 4, reducing dietary methionine together with reducing choline and vitamin B12 reduced egg size and improved shell quality with no adverse effect on egg production. The results of this series of experiments generally indicate that certain manipulations of the combination of methionine, choline, folic acid, and vitamin B12 have the potential to reduce egg weight and improve shell quality without affecting egg production during the latter stages of the egg production cycle.

Animal Feed↗
PubMed2006

Evaluation of eggshell quality of hens infected with Salmonella enteritidis by application of compression.

Eggs collected from hens of different ages and that differed in infection status with Salmonella enteritidis were evaluated for the ability to resist cracking following application of maximum compression load from an Instron materials testing machine. Orally infected 24-wk-old hens that were prepeak produced eggs with significantly lower hardness units (HU) of shells compared with a paired control group (P < or = 0.01). However, 1 of 3 additional infection trials in hens at peak (29 wk) and older hens postpeak (58 wk) showed an increase in HU in one trial and no difference in the other 2 trials. Thus, Salmonella enteritidis may be able to alter HU in a manner that is influenced by multiple factors, which include the age of the hen and the strain used for infection. Hardness was overall a sensitive physiological barometer of age, because readings correlated positively (all R > 0.50) with hens entering peak production, regardless of infection status. Detection of a very low HU reading (<1.0) was indicative of a hairline crack in the egg, which increased in incidence from 0.01% preinfection to 0.08% postinfection. Two other clinical signs noted postinfection in hens were that i) daily egg production significantly increased in older hens, and ii) emaciation was evident in a few hens that were infected by contact. These results suggest that there may be supportive approaches to achieve reduction of S. enteritidis in table eggs that do not rely on culturing.

Aging↗
PubMed1971

Eggshell thinning in Japanese quail fed mercuric chloride.

The eggs produced by developing Japanese quail (Coturnix coturnix japonica) fed 1 to 8 parts of mercury per million as mercuric chloride for 10 weeks have thinned shells. Total amounts of mercury in tissues were quite proportional to the dosage and were higher in males than in females. Methylation of mercury was not observed.

Animals↗
PubMed1990

Gas exchange across avian eggshells oscillates in phase with heartbeat.

Rahn et al. (J. Appl. Physiol. 69: 1546-1548, 1990) showed that the gas pressure in a plethysmograph containing an intact egg oscillates in phase with electrocardiogram (ECG) and that this pressure variation could be used as a noninvasive way to determine the heart rate of an avian embryo. One possible mechanism to account for the pressure oscillation is the mechanical movement of the embryonic heart, which leads to volume shifts of gas within the plethysmograph. Another possibility is that the oscillation of gas pressure with heartbeat is pulsatile gas exchange resulting from pulsatile blood flow. If gas exchange were transiently stopped, a pressure signal dependent on gas exchange should disappear, while a pressure signal dependent on cardiovascular motion should persist. Using a number of late-age hen eggs (at days 15-20 of incubation), we tested these hypotheses by suddenly changing the gas composition surrounding an egg and measuring the effect of the pressure oscillation. We found that 1) after 5% CO2-95% N2 was flushed into the plethysmograph (presumably halting gas exchange), pressure oscillations went almost to zero and the ECG signal remained; after air was flushed back to the plethysmograph, the pressure signal returned to control level; 2) after 20% CO2-20% O2-60% N2 was flushed into the plethysmograph (presumably increasing net gas exchange), the pressure signal increased 2.5-fold compared with that in air; and 3) after 1% CO2-99% N2 was flushed into the plethysmograph (presumably reversing gas exchange), the oscillation pressure decreased to one-fourth of that in air and the phase of pressure relative to ECG reversed compared with the phase in air.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pressure↗