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At least 289 records · Page 16Linked to original sources
PubMed2004

Top-down regression of the avian oviduct during late oviposition in a small passerine bird.

Egg production in oviparous vertebrates is assumed to be costly but the physiological basis of any costs remains unknown. The avian oviduct is a highly differentiated linear organ, with five functionally specific regions. Here we show that the oviduct regresses rapidly "from the top down" as soon as the more proximal regions have completed their function but while the distal regions still retain an oviductal egg. In zebra finches Taeniopygia guttata, oviduct mass did not differ between early laying birds at the 1-egg stage compared with late-laying birds (with one remaining yolky follicle; dry mass, 151-167 mg). However, in birds with no remaining yolky follicles but with an oviductal egg, oviduct mass decreased to 94 mg (44%). Regression occurred unequally among different regions of the oviduct, with significant decreases in the proximal infundibulum/magnum and isthmus regions (59% and 40%, respectively), but no change in distal shell gland/vagina mass. The shell gland did not regress until after the last oviposition. Thus, the avian oviduct has a highly regulated size-function relationship consistent with a high maintenance energy cost for this organ. We suggest that oviduct function is a significant contributor to the physiological costs of egg production and might mediate individual variation in maternal effects associated with non-yolk components of egg quality (e.g. immunoglobulins, lysozyme).

Animals↗
PubMed2003

Effects of various hormones on the sexual maturity of European eel (Anguilla anguilla L.) females from farm and lakes.

Previously described and alternative methods of the induction of sexual maturation in the European eel were investigated. Weekly administrations of a gonadoliberin agonist (nnRH-A=D-Phe6-GnRH-Ea) did not induce statistically significant effect on the gonads of treated eels in none of the dosages used (0.1 microg and 10 microg/fish). Carp pituitary extract and carp pituitary extract together with a dopamine antagonist caused considerable external changes (increase in eye size) and significant gonadal development in two treatment groups: wild and cultivated stocks. The induction of the ovulation by double amount of CP and gonadoliberin agonist with dopamine antagonist mixture was not successful in a wild stock. Fertilisation of stripped eggs of farm eel was attempted unsuccessfully in, due to low egg quality. An advanced phase of the sexual maturation process could be induced in specimen infected by Anguillicola crassus indicating, that nematode infection is not a limiting factor in the artificial propagation of the European eel.

Air Sacs↗
PubMed1981

Dwarfism in diverse genetic backgrounds. 4. Effects of dietary energy.

The interactions in the response of dwarf and normal genotypes to dietary energy were studied in lines of chickens divergently selected for high or low juvenile body weight. The genetic background of the dwarf genotype significantly affected body weights, egg production, and egg quality. The dietary energy levels used did not significantly affect these traits or the differences due to genetic background. Dwarf chickens were able to adapt to wide ranges of dietary energy when the diets contained sufficient crude protein.

Animal Feed↗
PubMed1984

Plasma phosphorus at 0, 6, and 21 hours postoviposition in hens laying in the morning or afternoon.

Two experiments were conducted using White Leghorn hens. Blood samples were collected immediately following oviposition (0 hr) or 6 or 21 hr postoviposition from hens laying in the morning or afternoon. Plasma phosphorus was determined at each time period. In Experiment 1, plasma phosphorus at oviposition was essentially the same for hens laying in the morning or afternoon (3.95 and 4.10 mg/dl, respectively). At 6 hr postoviposition plasma phosphorus was lower than that observed at 0 hr (3.22 and 3.15 mg/dl, respectively). When comparing plasma phosphorus levels at 21 hr postoviposition of hens laying in the morning or afternoon a higher (P less than or equal to .05) phosphorus level was observed for hens that laid in the morning (5.90 vs. 4.91, respectively). In Experiment 2, plasma phosphorus levels at 0 and 6 hr postoviposition were 3.32 vs. 3.18 and 2.81 vs. 2.74 mg/dl for hens laying in the morning and afternoon, respectively. At 21 hr postoviposition, phosphorus values of 5.30 vs. 3.65 mg/dl were reported for hens laying in the morning and afternoon, respectively. Data also indicated that on the day a hen does not lay an egg, plasma phosphorus does not rise. An hypothesis is offered to explain the difference in egg shell quality between eggs laid in the morning or afternoon.

Animals↗
PubMed1990

Influence of age at final beak trimming on pullet and layer performance.

Effects of final beak trimming on pullet and layer productivity were examined with three strains of commercial layers. All pullets were precision-trimmed at 7 days with final beak trimming at either 63, 84, or 105 days. Transient depressions of pullet body weight and feed consumption were noted in the periods immediately following beak trimming. Pullet mortality from 7 to 18 wk of age and 18-wk body weight were not significantly affected by beak trimming treatments. Strain effects were noted in rate of feed consumption following beak trimming. Age at 50% production was significantly later among birds trimmed at 63 days than among those trimmed at 84 or 105 days. Feed consumption, egg production, and mortality (140 to 441 days) were significantly lower among birds trimmed at 63 days than among those trimmed at 84 or 105 days. Egg quality and size were not influenced by beak trimming treatments.

Aging↗
PubMed1995

Influences of age at final beak trim on the productive performance of commercial layers.

Two commercial egg-type strains were beak-trimmed at 10, 10 and 63, or 10 and 84 d. There were no interactions between strain and beak trimming treatment. Pullet feed consumption was significantly reduced within the 14-d period following beak trimming at 63 or 84 d. Total pullet feed consumption (1 to 126 d) was significantly lower among birds trimmed twice than among those trimmed only at 10 d. At 126 d, body weight of pullets trimmed at 10 and 84 d or 10 and 63 d was significantly less than that of those trimmed only at 10 d. Pullet mortality was not significantly influenced by beak trimming treatments. No significant effects of beak trimming treatments on layer mortality, egg production, egg weight, egg mass, feed conversion, or egg quality were detected. Layer feed consumption was significantly greater among birds beak trimmed at 10 d than among those trimmed at 10 and 84 d. Most of the effects associated with beak trimming treatments can be attributed to the influence that beak trimming had on feed consumption.

Age Factors↗
PubMed2001

Changes in steroid hormone profiles and ovarian histology during salmon pituitary-induced vitellogenesis and ovulation in female New Zealand longfinned eels, Anguilla dieffenbachii gray.

To assess whether induced vitellogenesis in longfinned eels mimics that in naturally maturing conspecifics, female eels were artificially matured and steroid hormone status and oocyte cytology during oogenesis were evaluated. Successful induction of vitellogenesis was evident from the presence of yolk granules in the ooplasm of salmon pituitary homogenate (SPH)-injected, but not saline-, 17-hydroxyprogesterone-, and/or gonadotropin-releasing hormone-treated fish. In SPH-treated females, the migratory nucleus stage was reached after 33-53 days, followed by ovulation around 30 hours after induction of final maturation and ovulation. Only a portion of the germ cells matured, although resumption of vitellogenesis was seen in the majority of oocytes. In contrast, in ovaries of saline-injected controls, the most advanced oocytes were early vitellogenic. Atretic follicles were observed in ovaries of all eels, but abundance was greater in controls than in SPH-treated fish. SPH injections elevated plasma levels of estradiol-17beta and androgens, but not pregnenes, from within three days of treatment. Our results indicate that sex steroid levels in midvitellogenic hormone-treated females are similar to those in wild midvitellogenic females. In contrast, differences in yolk morphology of midvitellogenic follicles were seen between SPH-treated and wild females, especially in the second crop of midvitellogenic-sized oocytes measuring 300-400 microm in diameter. We discuss whether the observed differences affect egg quality, and perhaps explain the short life span of captive-bred eel larvae. J. Exp. Zool. 289:119-129, 2001.

17-alpha-Hydroxyprogesterone↗
PubMedDate not supplied

Molecular characterization of an infectious bronchitis virus strain isolated from an outbreak in vaccinated layers.

An infectious bronchitis virus (IBV) strain CT/7852/97 was isolated from a commercial layer flock experiencing decreased egg production and poor egg quality. Reciprocal virus neutralization test demonstrated that the isolate was closely related to Massachusetts, Arkansas, and JMK. With the use of both reverse transcription-polymerase chain reaction-restriction fragment length polymorphism and multiplex polymerase chain reaction methods, results consistently showed that CT/7852/97 isolate was Massachusetts serotype specific only. The nucleotide sequence of S1 polypeptide coding region of CT/7852/97 was determined and compared with the published sequences of 12 IBV strains from North America. The highest nucleotide homology with H120 (97%) and the least homology (62%) with Delaware (De/072/92) were observed. Massachusetts 41 and Beaudette shared 94% and 93%, respectively, nucleotide similarity with CT/7852/97, and Connecticut, JMK, and Arkansas 99 had 94%, 83%, and 78%, respectively, nucleotide similarity with CT/7852/97. Furthermore, no possible recombination site on S1 gene among Massachusetts 41, Arkansas 99, and JMK was detected in the isolate.

Amino Acid Sequence↗
PubMed2003

Effects of pulp and paper mill effluents on reproductive success of largemouth bass.

This study evaluated the effects of bleached and unbleached kraft mill effluent on reproductive success of largemouth bass (Micropterus salmoides). Bass were exposed to effluent concentrations (0, 10, 20, 40, or 80%) for 28 and 56 d. Parameters measured included hepatosomatic index (HSI) and gonadosomatic index (GSI) and plasma concentrations of 17beta-estradiol (E2), 11-ketotestosterone (11-KT), and vitellogenin (VTG). At the end of the 56-d period, bass were moved to hatchery ponds to evaluate spawning success. Spawning mats with eggs either were brought indoors for evaluation of fecundities, hatchabilities, and egg and fry size (measured at age 3 d), or were left in ponds and fry number and size recorded (average age of 14 d). Effluent exposure was verified by measuring resin acids (isopimaric, abietic. and dehydroabietic acids) in bile. Compared to controls, exposed bass had greater concentrations of resin acids in bile. In general, exposed females had lower concentrations of E2 and VTG (> or = 20% effluent), whereas males had lower concentrations of 11-KT (> or = 20% effluent) and increased E2 (> or = 20% effluent). The HSI values increased in females (> or = 10% effluent), and GSI values decreased in both sexes (> or = 40% effluent). Fecundity, egg size, and hatchability did not differ across treatments, but an increase in the frequency of fry abnormalities and a decrease in fry weights was observed at effluent exposures of 40% and higher. However, results from the pond study, revealed a significant reduction in fry growth and survival (> or = 10%). This decline may have been caused by an increased frequency of deformities, in conjunction with alterations of growth. These changes could have resulted from alterations in egg quality because of failure of parental reproductive systems, from acute embryo toxicity after translocation of contaminants from the mother to the developing embryo, or from both.

Animals↗
PubMed2003

Breeding performance of great tits (Parus major) along a gradient of heavy metal pollution.

The possible effects of heavy metal pollution on various breeding parameters of the great tit (Parus major) were studied at four study sites in a pollution gradient near a large nonferrous smelter in Belgium during three consecutive breeding seasons. Significantly more females interrupted their laying period near the pollution source than did females farther away. At the two most polluted sites, hatching success was significantly reduced compared to two lesser-polluted study sites. Overall breeding success was also significantly lower toward the factory complex. This lowered breeding success was caused not only by the decreased hatching success toward the pollution source but also by the significant difference in fledging success among sites. Although a clear relationship was observed between the exposure to heavy metal pollution and an impaired reproduction, not all reproductive parameters were affected. We found no significant differences in the onset of laying, clutch size, length of the incubation period, and the proportion of nests with low-quality eggs among sites. Although nest box occupancy was every year slightly lower toward the smelter compared to farther away, differences among study sites were never significant.

Animals↗
PubMed2005

[Comparison of different housing systems for laying hens in respect to economic, health and welfare parameters with special regard to organized cages (literature review)].

In conventional cages laying hens are subjected to restricted movement and a lack of ability to fulfil most of their natural behaviours. Thus, welfare and health of laying hens can be highly limited in conventional cages. Due to the rising criticism of conventional cages the EU passed a directive in 1999 (CEC, 1999) in order to ban conventional cages by the beginning of 2012. Because of this decision alternative housing systems like floor pens, aviaries or free range systems will gain importance in the future. In these housing systems laying hens have the opportunity to live out their natural behaviours to a higher extent. But also alternative housing systems have some disadvantages. Frequent infections leading to higher mortalities can be detected. Besides that egg production in alternative systems is often not so high and stable like in cages. Furnished cages and small-group-systems represent the attempt to retain the high economic and hygiene standards of conventional cages, while offering the hens the possibility to exercise and fulfil some of their natural behaviours. With regard to productivity, egg quality and bone strength this attempt seems to function, whereas keel bone deformities and the lack of ability to live out natural behaviours are still problems in furnished cages.

Animal Husbandry↗
PubMed1990

Polypronuclear embryos after in vitro fertilization.

Triploidy occurs in 1% to 3% of recognized conceptions in vivo. In vitro fertilization (IVF), which places large numbers of sperm in proximity to the oocyte, may increase the risk of triploidy. The risk also could be influenced by stimulation protocols that differentially affect egg quality. We found no significant difference in triploidy when cycles were stimulated with clomiphene citrate/human menopausal gonadotropin (3.2%) compared with gonadotropin-releasing hormone analog/human menopausal gonadotropin stimulation (4.4%). Triploidy was less common with male factor infertility (0.7%) compared with other causes of infertility (3.4% to 3.8%). Triploid embryos can develop to cleavage stages indistinguishable from those generated by diploid embryos. Thus, identifying and discarding embryos with greater than 2 pronuclei is a vital function of an IVF laboratory.

Cell Nucleus↗
PubMed1994

[Urinary luteinizing hormone surge and outcome of in vitro fertilization and embryo transfer].

This study was based on 150 in vitro fertilization cycles carried out between June 1991 and July 1992. All the patients had blocked or dysfunctional fallopian tubes as the cause of infertility. Clomiphene citrate, human menopausal gonadotropin and hCG were used for controlled ovarian hyperstimulation. The results showed that an urinary luteinizing hormone (LH) surge (LH > 40 IU/L) occurred in 41 cycles (27.33%), a high LH level (LH = 40 IU/L) in 16 (10.67%), and normal (LH < 40 IU/L) LH level in 93 cycles, before hCG injection. The average number of oocytes recovered was not affected by the occurrence of a spontaneous LH surge, but the cleavage rate of the fertilized eggs was significantly lower than that in the cycles without LH surge and the rate of clinical pregnancy was also lower, although of no statistical significance. Our results demonstrated that the LH surge had an adverse effect on the egg quality and therefore would probably reduce the chances of pregnancy success.

Adult↗
PubMed1979

[Keeping quality of hard boiled eggs].

Only a few and contradictory results are available on the storage stability of hard boiled eggs which are of considerable importance for institutional feeding. Therefore four storage experiments on about 500 hard boiled eggs each were carried out and chemical and sensorial changes occurring during storage investigated. The one-day-old eggs of the same origin were boiled for 17 minutes under standard conditions and subsequently stored in air at a relative humidity between 73 and 85% at 4 degrees C (experiment No. 1), at 20 degrees C (experiments No. 2 and 3) and in pure carbon dioxide at 20 degrees C (experiment No. 4). Immediately after boiling, the eggs used for experiments No. 3 were dipped into coloured resin for egg shells (natural Manila-Kopa; dissolved in ethanol and stained with "Acillantechtgrün). Losses in weight during storages were distincly lower in the lacquered eggs than in the non-lacquered samples otherwise treated in the same manner. The weight decrease caused by the loss of water was extraordinarily high in pure CO2 and is due mainly the the decrease of the pH in the egg whites caused by the uptake of CO2. A few days after boiling the concentration of the free amino acids reached approximately the same level in albumen and yolk and remained practically constant over the following 3 weeks. For the breakdown of lecithine in yolk determined according to Grossfeld and Peter, a "deterioration quotient" of 6, like in unboiled eggs, was fixed as the limit value for unspoiled condition. Accordingly a possible storage time of 3 to 4 weeks resulted for the eggs stored at 4 degrees C and for the eggs treated with stained resin. The non-lacquered eggs stored in air or in CO2 at 20 degrees C reached the critical value in about 10 days. From the vitamins A, B1 and B2 only vitamin A showed considerable losses during storage. On the basis of the microbiological (3) and chemical findings and of the sensorial evaluation of colour, consistency, odour and taste of egg whites and yolks, the following storage times were determined for eggs in the quality class "saleable" requiring an overall rating not lower than 6 (satisfactory): 14 to 16 days, for non-lacquered eggs stored at 4 degrees C and for lacquered eggs at 20 degrees C whereas 5 days were found to be the maximum storage time for untreated eggs stored at 20 degrees C. If boiled eggs are stored in pure carbon dioxide at 20 degrees C, a distinct quality loss is observed already after a few days.

Animals↗
PubMed1991

Effect of dietary boron supplementation on egg production, shell quality, and calcium metabolism in aged broiler breeder hens.

Three experiments were conducted using aged broiler breeder hens (greater than 60 wk) to investigate the effects of supplemental B on egg production (EP), shell quality, and Ca metabolism. Experiment 1 had a 2 x 2 factorial arrangement of treatments: 1) high Ca (3.5%); 2) high Ca plus B; 3) low Ca (1.5%); and 4) low Ca plus B; using 32 60-wk-old hens. The B levels were basal and 100 ppm supplemental for the first 2 wk of the experiment and reduced to 60 ppm for the remaining 3 wk. Egg production, shell thickness (ST), and egg specific gravity (SG) were recorded weekly. In Experiment 2, 40 60-wk-old hens were divided into two groups: high and low shell quality. Each group was further divided into two subgroups and fed a low-Ca basal diet with or without supplemental B. The level of B supplementation and the experimental period was the same as in Experiment 1. In Experiment 3, 52 75-wk-old hens were force-molted. After molting, 36 hens were fed a commercial layer diet with the remaining 16 hens fed the control diet supplemented with 100 ppm B. Blood samples were taken during the nonlaying and laying periods, respectively. The results showed that B significantly (P less than .05) depressed EP in Experiment 1 but not in Experiments 2 and 3. Supplemental B decreased plasma Ca when hens were fed a diet containing high Ca levels (3.5%). Supplemental B did not affect SG, ST, or Ca retention, but did significantly increase tibial bone ash percentage (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMedDate not supplied

Avian adenoviruses: effect on egg production, shell quality, and feed consumption.

Four avian adenovirus isolants (Indiana C, DPI-2, IBH-2, and B-3)were examined for pathogenicity in laying birds. None affected shell quality, and only one (IBH-2) had even a minimal effect on egg production (faster decline). Of three isolants tested (Indiana C, DPI-2, and IBH-2), only IBH-2 caused feed intake to be reduced. No other clinical signs were observed during these experiments. Egg transmission, virus excretion, and antibody production were found to mimic patterns reported for serotype-1 avian adenoviruses.

Adenoviridae Infections↗
PubMed2000

Effects of dietary vitamin E on the quality of table eggs enriched with n-3 long-chain fatty acids.

Because of the proposed cardioprotective benefits of n-3 fatty acids and vitamin E, a trial was carried out to investigate the possibility of enriching eggs with n-3 fatty acid and vitamin E added to the hen's diet. One hundred ninety-two Hy-Line Brown hens, 39-wk-old, were divided into eight groups: four groups received the basal diet supplemented with 3% lard and four doses of dl-alpha-tocopheryl acetate (0, 50, 100, and 200 ppm), whereas the diets of the other groups were supplemented with 3% of fish oil and the same doses of vitamin E. The performances of the hens and egg weights were not affected either by the type of lipid supplement or by the vitamin level. The treatment with fish oil caused a dramatic increase (P < 0.01) of all n-3 fatty acids of the yolk, particularly EPA (19.53 vs. 0.74 mg/egg) and DHA (143.70 vs. 43.66 mg/egg), and an appreciable decrease of arachidonic acid (25.54 vs. 67.72 mg/egg). The different levels of dietary vitamin E slightly affected the fatty acid composition of the yolk. Yolk alpha-tocopherol increased linearly as dietary dl-alpha-tocopheryl acetate increased (P < 0.01) from the control level of 90.93 microg/g of yolk to 313.84 microg/g of yolk when 200 ppm were added to the hen diets. Twenty-eight days of storage at room temperature (20 to 25 C) did not alter the yolk fatty acid profile, and, moreover, the levels of vitamin E remained still very close to those observed in fresh egg.

Animal Nutritional Physiological Phenomena↗