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At least 793 records · Page 44Linked to original sources
PubMed2001

Toxic effect of garlic extracts on the eggs of Aedes aegypti (Diptera: Culicidae): a scanning electron microscopic study.

The surface features of the eggs of Aedes aegypti (L.) and the effect of garlic extracts on their hatching were studied by scanning electron microscopy. The exochorion and endochorion layers of the eggshells display an essentially pentagonal reticulation. The exochorion meshwork exhibits large and small papillae interconnected by horizontal struts. At higher magnification, the large papillae show aeropyles on their rough surface. Eggs hatched in deionized water undergo complete fracture near the anterior poles producing free shell caps. In contrast, eggs placed in 6% reconstituted Kyolic garlic extract are only partially fractured, display attached shell caps, and the larvae remain trapped within the shells. In the natural garlic bulb extract, the eggs show no fracture lines in their shells. No larvae were observed either alive or dead in the garlic extracts, suggesting the embryos were disabled before they could escape from their eggshells as viable larvae. It is concluded that aqueous extracts of garlic inhibit hatching of Aedes eggs. Thus, compounds in garlic may be beneficial in the control of mosquitoes.

Aedes↗
PubMedDate not supplied

The effects of 6/85 live Mycoplasma gallisepticum vaccine in commercial layer hens over a 43-week laying cycle on egg production, selected egg quality parameters, and egg size distribution when challenged before beginning of lay.

In each of two trials, 80 commercial leghorn-type pullets were separated into two treatments with four replicates of 10 chickens in each treatment. Forty pullets were designated as controls and received no inoculation, whereas the remaining 40 pullets received the 6/85 vaccine strain of Mycoplasma gallisepticum (MG) at 10 wk of age. Hen-day egg production, egg weight, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded weekly in each trial through an entire laying cycle of 43 wk. Further, eggs from all treatments were collected daily, Monday-Thursday, and individually weighed. No significant difference was observed between the treatments for 43-wk means for hen-day egg production, for any of the monitored egg or eggshell quality parameters, or for the number of extra large, large, medium, small, pee wee, or undergrade egg sizes. A significant (P < or = 0.05) difference was observed for the number of jumbo-sized eggs between the two treatments. Results of this study suggest that vaccination of commercial layer chickens at 10 wk of age with 6/85 strain MG does not detrimentally impact egg production, egg size distribution, or ovary/oviduct function as evidenced by selected egg parameters monitored in this study.

Animals↗
PubMedDate not supplied

Effect of electrostatic space charge on reduction of airborne transmission of Salmonella and other bacteria in broiler breeders in production and their progeny.

Salmonella in birds is a concern because of the human foodborne illness associated with the consumption of poultry meat and eggs. One of the methods of transmission of Salmonella within a flock can be by the air. Therefore, we used reduction of transmission of Salmonella to monitor the effectiveness of the electrostatic space charge system (ESCS). During the average broiler breeder laying cycle of 40 wk, a large amount of dust becomes airborne and accumulates on walls, ceiling, and equipment. Many microorganisms adhere to these dust particles, making dust an excellent vector for horizontal disease transmission between birds. We used two environmentally controlled rooms containing commercial broiler breeders to evaluate the effectiveness of an ESCS that produced a strong negative electrostatic charge to reduce airborne dust and, subsequently, microorganism levels. The ESCS caused the dust to become negatively charged, therefore moving to the grounded floor in the treatment room. The use of the ESCS resulted in a significant reduction (P < 0.0001, 61% reduction) in airborne dust concentration levels, which resulted in a significant reduction (P < 0.0001, 76% reduction) in total airborne bacteria and gram-negative bacteria (48% reduction) in the treatment room. Significant reductions (P < 0.05) of gram-negative bacteria (63% reduction) on the egg collection belts were also recorded in the treatment room, which resulted in a significant reduction (P < 0.0001) of gram-negative bacteria (28% reduction) on the eggshell surface. The ESCS treatment resulted in fewer Salmonella enteritidis-positive hens and their progeny from the treatment room due to reductions of dust and airborne bacteria. In addition, this significant reduction in bacteria on the eggshell surface should result in less bacteria in the day-old chicks, therefore better early chick livability. There was no significant difference (P > 0.05) in egg production, male or female body weights, mortality, or reproductive performance in the ESCS room compared with the control room.

Air Microbiology↗
PubMed2003

Formation of benzo[a]pyrene and 7,12-dimethylbenz[a]anthracene adducts in vascular endothelia of cytochrome P4501A-induced chicken embryos.

Polycyclic aromatic hydrocarbons (PAHs) are widespread in the environment and birds may be exposed to PAHs via diet, from preening feathers contaminated with oil, or through contamination of the eggshell during embryo development. In the present study, tissue distribution and the cell-specific binding of two labeled PAHs, benzo[a]pyrene ([3H]BaP) and 7,12-dimethylbenz[a]anthracene ([3H]DMBA), were examined in chicken embryos exposed in ovo to CYP1A inducers. Tape-section autoradiograms revealed high concentrations of radioactivity in the bile, liver, kidneys, heart, and leptomeninges. Light microscopy autoradiography of solvent-extracted tissue slices showed a high and selective binding in endothelial cells in certain blood vessels in brain, heart, lung, and chest muscle. Binding was also observed in blood vessel endothelial cells in the chorioallantoic membrane (CAM), an extraembryonal tissue lining the eggshell. Endothelial binding was confirmed in CAM exposed in vitro, implying that tissue-binding metabolites were formed in situ. The CYP1A inhibitor ellipticine abolished bleeding in the target endothelial cells in CAM. It is thus concluded that blood vessel endothelia in various tissues in birds can bioactivate environmental contaminants and be targets for their toxicity. In view of its critical position beneath the shell, the CAM could be an important target for toxicants following external exposure in oviparous species.

Animals↗
PubMed2005

Changes in productivity and contaminants in bald eagles nesting along the lower Columbia River, USA.

Previous studies documented poor productivity of bald eagles (Haliaeetus leucocephalus) in the lower Columbia River (LCR), USA, and elevated p,p'-dichlorodiphenyldichloroethylene (DDE), polychlorinated biphenyls (PCBs), dioxins, and furans in eagle eggs. From 1994 to 1995, we collected partially incubated eggs at 19 of 43 occupied territories along the LCR and compared productivity and egg contaminants to values obtained in the mid-1980s. We found higher productivity at new nesting sites along the river, yet productivity at 23 older breeding territories remained low and was not different (p = 0.713) between studies. Eggshell thickness at older territories had not improved (p = 0.404), and eggshells averaged 11% thinner than shells measured before dichlorodiphenyltrichloroethane use. Decreases in DDE (p = 0.022) and total PCBs (p = 0.0004) in eggs from older breeding areas occurred between study periods. Productivity was not correlated to contaminants, but DDE, PCBs, and dioxin-like chemicals exceeded estimated no-effect values. Some dioxin-like contaminants in eggs were correlated to nest location, with highest concentrations occurring toward the river's mouth where productivity was lowest. Although total productivity increased due to the success of new nesting pairs in the region, egg contaminants remain high enough to impair reproduction at older territories and, over time, may alter productivity of new pairs nesting near the river's mouth.

Animals↗
PubMed2004

Elemental characterization of Daphnia resting eggs by X-ray analytical microscopy.

Resting eggs of Daphnia, a key crustacean zooplankton of freshwater food chains, can remain viable for more than a century. These eggs are able to withstand freezing and drying, and can survive the harsh environment of a predator's digestive system. Until recently little was known about the chemical composition, microanatomy, and physical properties of the resting eggs. The current study utilized a physical technique, the X-ray analytical microscope, to identify and localize component elements of the Daphnia resting egg. The analysis demonstrated that phosphorus, sulfur, potassium, and calcium were detected as elemental components of the resting egg, and detection intensities of the four elements differed according to the position of the eggs. Phosphorus and calcium were mostly detected in regions of the eggshell that surrounded the two embryos. In addition, sulfur was distributed throughout the eggshell whereas potassium was localized to the areas that corresponded to where the embryos were encased. Through the use of X-ray analytical microscopy, the current study identifies elemental characteristics in relationship to the structure of the Daphnia resting eggs.

Animals↗
PubMed2004

In vitro development of the fish parasite Hysterothylacium aduncum from the third larval stage recovered from a host to the third larval stage hatched from the egg.

Anisakids are parasitic nematodes of fish worldwide, producing economic and human health concerns. It is thus important to ascertain their in vitro life cycle in laboratory studies. Here we describe the in vitro development of third-stage larvae (L3) of Hysterothylacium aduncum isolated from blue whiting Micromesistius poutassou, to the hatching of L3 from eggs obtained from H. aduncum worms grown in GLIT medium (a modified mixture of Yaeger's LIT [Liver Infusion Tryptose] and Grace's media) at pH 4.0, 13 degrees C and with 5% CO2 in air. Under these conditions, L3 recovered from fish developed to mature adults (3.4 to 6.2 cm in length), with oviposition starting from Day 26 in culture. Fertilized eggs (mean size 64 x 52 microm) had a thick, rugose eggshell and were larger than unfertilized ones (mean size 49 x 42 microm), whose eggshells were thin and smooth. Eggs laid during the first and second week of oviposition, and maintained in 2.8% NaCl solution at 13 degrees C, developed to L3. Under these maintenance conditions, between 20.6 and 52.5% of the eggs laid during the first week developed into larvae. Motile larvae, enclosed in a sheath, hatched from between 2 and 11% of these eggs. The larvae started to hatch 23 d after deposition. These larvae were 144 to 215 microm in length, enclosed in a 237 to 305 microm-long sheath. This GLIT culture medium may help to study the biology of this and other anisakids.

Animals↗
PubMed1990

The effect of 1 alpha,25-dihydroxyvitamin D3 added to a layer diet containing adequate amounts of vitamin D3 on the performance of layers.

The effect of adding 1 alpha,25-dihydroxyvitamin D3 (calcitriol) to a well-balanced, commercial layer diet containing 1,900 IU vitamin D3/kg on eggshell quality and laying performance of 56-wk-old White Leghorn hens was investigated. After 8 wk of treatment, calcitriol at 1.5 micrograms/kg diet had no discernible effect on egg weight, egg deformation, percentage shell, shell thickness, feed consumption, and egg production. At 3.0 and 4.5 micrograms/kg, feed consumption, feed production, and egg weight were significantly reduced, whereas egg deformation, percentage shell, and shell thickness were not affected. The results show that calcitriol added to a diet already adequately supplemented with vitamin D3 does not improve eggshell quality and may impair laying performance.

Animals↗
PubMed1990

Hematological indices of turkey embryos incubated at high altitude as affected by oxygen and shell permeability.

Turkey eggs (Meleagris gallopavo) were incubated at an altitude of 1,707 m to test the effects of oxygen supplementation and increased eggshell permeability by removal of shell cuticle on embryonic hematology. Turkey embryo hematological indices measured were red blood cell count (RBC), hemoglobin concentration, packed cell volume, mean cellular volume, mean cellular hemoglobin, and percentage of reticulocytes. Although hemoglobin concentration measured during pipping increased as expected by increasing RBC, no significant differences were observed between oxygenation, or permeability treatments, or their interaction. Under the high altitude conditions of the present experiment, increased hemoglobin concentrations in all treatments corresponded to increased numbers of erythrocytes with constant mean cellular hemoglobin. None of the remaining hematological indices examined was affected by oxygen or permeability treatments. It was concluded that turkey embryos incubating at 1,707-m elevation make no additional changes in hemoglobin concentrations during the plateau stage in oxygen consumption (25, 26, and 27 days of incubation) when exposed to increased oxygen tension (151 mm Hg versus 135 mm Hg) or increased eggshell permeability (19.9 mg H2O/day per mm Hg versus 23.2 mg H2O/day per mm Hg).

Altitude↗
PubMed1990

Bioavailability of fluorine in sepiolite for laying hens.

The purpose of the present work was to compare the bioavailability of structural fluorine contained in sepiolite and in sodium fluoride for laying hens. Three hundred 27-wk-old laying hens were fed one of three diets: 1) a control based on corn, barley, and soybean meal containing 21 mg/kg of fluorine; 2) a sepiolite diet in which 2% sepiolite replaced 2% barley in the control diet and which contained 217 mg/kg of fluorine; and 3) a NaF diet, consisting of the same control diet to which NaF was added to contain 217 mg/kg of fluorine (the same level of F- as the sepiolite diet). The experiment ended when hens were 64 wk old. Fluorine concentration in the tibial bone of hens fed the NaF diet was four times higher than in the control, and twice as high in eggshell. In contrast, hens fed sepiolite had fluorine concentrations in tibial bone and eggshell not significantly higher than fluorine concentrations in the controls. These results indicate that fluorine from sepiolite was not available. The effects of the different diets on egg production, feed intake, feed conversion, egg weight, shell and interior egg quality, dry matter of feces, and body weight gain were also determined but no significant differences due to the dietary treatment were observed.

Animals↗
PubMed1992

Response of early- and late-maturing commercial Leghorn pullets to low levels of dietary phosphorus.

An experiment with a 2 x 2 factorial arrangement of treatments was used to determine differences in responses of early-maturing (EM) and late-maturing (LM) pullets fed low dietary P (.4% total P; LP) and normal dietary P (.7% total P; NP) levels. Six hundred pullets (18-wk-old) were equally and randomly allocated to the LP and NP treatments. Egg production, egg weight, egg specific gravity, and eggshell breaking strength were measured at 26 and 28 wk. When pullets were 28 wk of age, plasma total Ca (TCa), ionic Ca (Ca++), and inorganic P (Pi) concentrations, urine Ca concentrations, and urine pH, bone mineral content (BMC), bone density, total kidney weight, and kidney weight ratio (heavier kidney divided by lighter kidney) were determined from 15 pullets each from EM-NP, EM-LP, LM-NP, and LM-LP treatments. The pullets with osteoporosis and pullets that died during the experiment were categorized into EM and LM groups. Results showed that LP caused severe adverse effects on LM pullets. The LM pullets fed the LP diet had high plasma Ca++ concentration, low plasma Pi concentration, increased urine Ca concentration, a high incidence of osteoporosis, mild kidney lesions, and elevated mortality compared with pullets subjected to the other treatments. The EM pullets fed the LP diet were also adversely effected by LP, but were less susceptible to osteoporosis and mortality. The LP diet improved eggshell quality, but this beneficial effect was only temporary. The severity of adverse effects of low dietary P was greater for LM than the EM pullets.

Animals↗
PubMed1992

Effect of oxygen and maternal dietary iodine on embryonic carbohydrate metabolism and hatchability of turkey eggs.

Fertile turkey eggs were produced by hens fed supplemental iodine to decrease eggshell conductance. The eggs were then incubated in an oxygen-enriched environment during Days 25 and 26 of incubation to test the hypothesis that maternal dietary iodine has separate effects on the eggshell permeability and the developing embryo. Oxygen supplementation improved hatchability regardless of dietary iodine treatment, suggesting that oxygen availability may limit hatching of eggs with normal gas conductance. Oxygen and dietary iodine did not affect body weight but interacted prior to pipping to affect embryonic liver and heart glycogen. Dietary iodine increased liver glycogen at internal pipping. The effects of oxygen on embryos, which were correlated directly with hatchability, were increased liver growth prior to pipping and increased heart weight at external pipping and posthatching. It was concluded that supplementing oxygen to incubating turkey eggs may improve hatchability by increasing liver and heart growth. Dietary iodine played only a minor or modulating role in assisting embryos to survive.

Animal Feed↗
PubMed1992

Calcium and carbonate supply in the shell gland of hens laying eggs with strong and weak shells and during and after a rest from lay.

The concentration of calcium-binding protein (CaBP) and the activities of calcium adenosine triphosphatase (Ca(2+)-ATPase) and carbonic anhydrase (CA) were determined in the shell gland mucosa of hens in two experiments. In Experiment 1, laying hens on a proprietary layer mash were compared with hens rested from lay by the feeding of whole grain barley. In Experiment 2 comparisons were made of laying hens fed the proprietary layer mash and producing eggs with either strong or weak shells. These latter comparisons were also made when the shell gland was quiescent or active with respect to daily eggshell formation. Feeding whole grain barley reduced egg production to zero after 11 days. This reduction in rate of lay was accompanied by significant reductions in all three markers, the effect on Ca(2+)-ATPase and CaBP being less than for CA. Control values were regained between 10 and 16 days after the barley was replaced with the layer mash. Relative shell strength and the physiological status of the shell gland with respect to time of daily eggshell formation had no significant effect on any marker in Experiment 2.

Animal Feed↗
PubMed1993

Liquid methionine hydroxy analog (free acid) and DL-methionine attenuate calcium-induced kidney damage in domestic fowl.

To evaluate the possibility that kidney damage may be induced by the commercial practice of feeding high-Ca (HCa) prelayer rations, and to evaluate the protective efficacy of supplementing HCa diets with liquid methionine hydroxy analog free acid or DL-methionine, 12-wk-old female Single Comb White Leghorn pullets were fed one of the following corn-soybean meal-based diets until they reached 22 wk of age: normal-Ca (NC, 1% Ca); HCa (HC, 3.5% Ca); HCa supplemented with .34 or .68% liquid methionine hydroxy analog free acid (HC3A or HC6A); or HCa supplemented with .3 or .6% DL-methionine (HC3DL or HC6DL). The unsupplemented HC diet caused a significant reduction in kidney mass and a significant increase in the incidence of gross kidney damage and urolithiasis in pullets necropsied at 22 wk of age. Calcium-induced kidney damage was attenuated in a dose-response fashion by supplementing the HC diet with liquid methionine hydroxy analog and DL-methionine. None of the diets caused a significant metabolic acidosis. Plasma uric acid concentrations were not predictive of the extent of Ca-induced kidney damage. Analyses of glomerular size distributions indicated that subclinical or "hidden" kidney damage may not progressively develop into urolithiasis as hens mature. When compared with hens reared on the NC diet, rearing hens on the HC, HC3A, HC3DL, HC6A, or HC6DL diets did not consistently affect hen-day egg production, egg mass, eggshell mass, percentage eggshell, or bone mineralization.

Animals↗
PubMed1993

Effect of maternal dietary triiodothyronine on embryonic physiology of turkeys.

The objective of the present experiment was to feed triiodothyronine (T3) to lines of turkey breeders selected for egg production and growth, and an unselected control line. The data were collected to determine a genetic basis for thyroid-mediated maternal effects on embryonic physiology and livability. At 30 wk of age, turkeys of the three lines were photostimulated and half of each line was fed a diet containing .5 ppm T3. Maternal dietary T3 increased egg weight, reduced yolk solids and eggshell conductance constants, and increased albumen solids and water in eggs in all lines compared with control eggs. Hatchability in all lines was not affected by the dietary treatment (Control = 72.2%; T3 treatment = 70.7%), but there was a significant interaction between dietary T3 and line of turkey for the time of embryonic mortality, time of hatching, and carbohydrate metabolism of the embryo. The T3 increased mortality of the Egg line and unselected line during pipping, increased mortality of the Growth line in the plateau stage, but decreased its mortality during internal pipping. Reduced glycogen in liver as well as a reduced gluconeogenesis were evident in embryos of the two selected lines fed T3. It is concluded that genetic lines may have different metabolic patterns based on their genetic constitution in order to compensate for variations in egg solids and eggshell conductance constants. The metabolic patterns are reflected in different levels of embryonic blood plasma glucose, glycogen, and gluconeogenesis.

Animals↗
PubMed1994

Responses of laying hens to diets containing up to 2% DL-methionine or equimolar (2.25%) 2-hydroxy-4-(methylthio)butanoic acid.

Diets supplemented with up to .6% DL-Met (DLM) or .68% 2-hydroxy-4-(methylthio)butanoic acid (HMB, Alimet) acidify the urine and reduce the incidence of urolithiasis in pullets and laying hens. Excessive acidification potentially may reduce eggshell quality and bone mineralization by interfering with Ca metabolism and may severely challenge the liver and kidneys, which are the primary organs responsible for attenuating metabolic acidosis. To evaluate these possibilities, 30-wk-old Single Comb White Leghorn hens in full production (five hens per replicate, six replicates per diet treatment) were fed for 30 d a 15.7% CP corn and soybean meal-based control layer ration alone or supplemented with DLM (.5, 1, 1.5, or 2%) or equimolar HMB (.56, 1.13, 1.69, or 2.25%). None of the diets caused mortality or gross hepatic or renal damage. Hens fed diets supplemented with the highest levels of DLM and HMB exhibited significant reductions in feed intake, hen-day egg production, and liver mass and had lower plasma concentrations of alanine amino-transferase and isocitrate dehydrogenase when compared with hens fed the control diet. Kidney mass was not significantly affected by high levels of DLM or HMB, but plasma uric acid was significantly higher in hens fed 2% DLM compared with hens fed the control diet. The highest levels of DLM and HMB did not significantly alter total plasma Ca or inorganic phosphate concentrations, nor were percentage eggshell or femur mineralization (femur ash mass:defatted bone mass, femur ash mass:bone volume) significantly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1996

The long-term productivity of hens housed in battery cages and an aviary.

This study examined the long-term effects of housing system on several aspects of laying hen production. At 19 wks of age, 336 White Leghorn hens were placed, 3 birds per cage, into battery cages; 437 birds were assigned to an aviary with communal nests, ambulation areas, and three raised tiers with feeders and drinkers. Family groups were split between the two housing systems. The hens were housed in such a manner for over 3 yr (until the end of the 168th wk of age), with forced molts between 66 and 74 and between 119 and 125 wk of age. Feed consumption and conversion, egg weight, eggshell deformation, and hen-day productivity were assessed monthly in both systems. Although feed consumption and conversion tended to be higher in the aviary throughout the study, these variables differed significantly due to housing system only in Year 2 (P = 0.04). There were no differences in egg weight (P = 0.7), eggshell deformation (P = 0.85), egg cracking during shaking (P = 0.34), total hen-day productivity (P = 0.55), or egg mass produced per hen per month (P = 0.4). Although aviary systems have been criticized for egg losses due to floor laying, only 2.5% of eggs in the current study were laid on the floor in Year 1, and 0.3% in Years 2 and 3; 1.7% across all years. Hen mortality was variable across production and molt periods, and did not differ due to housing system (P > 0.05). The results of this study confirm that hen productivity in well-managed alternative housing systems can compare favorably with that in battery cages.

Animals↗
PubMed1981

Immunoperoxidase localization by electron microscopy of soluble egg antigen and human IgG in circumoval precipitin reactions around Schistosoma mansoni eggs.

Soluble egg antigen and human IgG were localized by the unlabelled antibody enzyme technique for electron microscopy on Schistosoma mansoni eggs having circumoval precipitin reactions. Reaction products indicating the presence of soluble egg antigen were on portions of the circumoval precipitate outside the egg, between the eggshell and vitelline membrane, and between the vitelline membrane and miracidium inside the egg. Reaction products indicating human IgG were only found on portions of the circumoval precipitate external to the eggshell.

Animals↗