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PubMed1995

Responses of laying hens to forced molt procedures of variable length with or without light restriction.

The importance of the length of the rest period and of photoperiod as components of the forced molt procedures was evaluated in 650- and 560-d-old Lohman hens. The procedure included an 8-d feed withdrawal phase and rest periods varying from 0 to 35 d, during which the birds were fed for maintenance only. In the first trial, forced molt was applied with or without omission of artificial illumination. The rest period varied between 2 and 20 d. In the second trial, all treatments included omission of artificial illumination, and a variable rest period between 0 and 35 d. Egg production ceased, after 4 to 5 d of feed withdrawal and resumed 8 to 15 d after the end of the rest period, without any consistent response to its length. Forced molt stimulated egg production rate and diminished its age-dependent rate of decline, reduced the proportion of broken and shell-less eggs, and improved shell quality. Following wide oscillations proportional to the length of the rest period, egg weight stabilized at levels similar to that of the unmolted controls. Feed intake was stimulated by forced molt to levels exceeding those of the control hens. Body weight increased during the postmolt period to levels slightly exceeding those of unmolted controls. Results of one trial show that omission of artificial illumination was essential for the full expression of the molt responses. In the other trial, production rate and shell quality were improved and the percentage of broken eggs was reduced when the length of the rest period was increased. Maximal improvements appears to have been reached with rests period of 14 to 21 d.

Animals↗
PubMed2005

Outgrowth of Salmonellae and the physical property of albumen and vitelline membrane as influenced by egg storage conditions.

This study was undertaken to determine the influence of storage time and temperature on the volume, weight, and pH of egg albumen, the physical strength of vitelline membrane, and the fate of Salmonella Enteritidis artificially inoculated into egg albumen. A fiber-optic probe was used for inoculation with Salmonella Enteritidis at 10(2), 10(4), or 10(6) cells per egg. Both fresh and inoculated eggs were stored at 4, 10, and 22 degrees C for 6 weeks. Five fresh uninoculated eggs from each storage group were collected each week, and the weight, volume, and pH of the egg albumen were measured. The forces, energies, and degrees of membrane deformation required to rupture the vitelline membranes also were determined from either albumen-free yolks or yolks surrounded by albumen. In separate experiments, five inoculated eggs were evaluated each week for populations of Salmonella Enteritidis. When the eggs were stored at 4 degrees C, the albumen retained significantly more volume and weight and had a relatively lower pH. The vitelline membranes from eggs stored at 4 and 10 degrees C required more force and energy for rupture. Salmonellae flourished at 22 degrees C, even in the albumen with the lowest initial population, 10(2) cells per egg. Storage at 4 and 10 degrees C inhibited the growth of salmonellae in the albumen of eggs with initial populations of 10(2), 10(4), or 10(6) cells per egg. In eggs with initial Salmonella populations of 10(6) cells per egg that were stored at 22 degrees C, the populations of reached as high as 10(10) cells per egg after 4 weeks of storage. Storage at 4 and perhaps 10 degrees C postponed the aging process of chicken eggs, preserved the antimicrobial agents of the albumen, and maintained the integrity of vitelline membrane. Low-temperature storage therefore had a significant impact on the safety and overall quality of the eggs.

Animals↗
PubMed2006

The evolution of egg colour and patterning in birds.

Avian eggs differ so much in their colour and patterning from species to species that any attempt to account for this diversity might initially seem doomed to failure. Here I present a critical review of the literature which, when combined with the results of some comparative analyses, suggests that just a few selective agents can explain much of the variation in egg appearance. Ancestrally, bird eggs were probably white and immaculate. Ancient diversification in nest location, and hence in the clutch's vulnerability to attack by predators, can explain basic differences between bird families in egg appearance. The ancestral white egg has been retained by species whose nests are safe from attack by predators, while those that have moved to a more vulnerable nest site are now more likely to lay brown eggs, covered in speckles, just as Wallace hypothesized more than a century ago. Even blue eggs might be cryptic in a subset of nests built in vegetation. It is possible that some species have subsequently turned these ancient adaptations to new functions, for example to signal female quality, to protect eggs from damaging solar radiation, or to add structural strength to shells when calcium is in short supply. The threat of predation, together with the use of varying nest sites, appears to have increased the diversity of egg colouring seen among species within families, and among clutches within species. Brood parasites and their hosts have probably secondarily influenced the diversity of egg appearance. Each drives the evolution of the other's egg colour and patterning, as hosts attempt to avoid exploitation by rejecting odd-looking eggs from their nests, and parasites attempt to outwit their hosts by laying eggs that will escape detection. This co-evolutionary arms race has increased variation in egg appearance both within and between species, in parasites and in hosts, sometimes resulting in the evolution of egg colour polymorphisms. It has also reduced variation in egg appearance within host clutches, although the benefit thus gained by hosts is not clear.

Animals↗
PubMed1992

The effect of light source and intensity on turkey egg production.

The effect of light source and intensity on egg production, fertility, hatchability, egg weight, and shell quality in turkey hens was investigated. Turkey hens were exposed to either incandescent, high-pressure sodium vapor (HPSV), or daylight fluorescent (FL) lights at an intensity of 21.6 1x during the growth phase (after 8 wk). During the breeder phase, hens were assigned to the same light sources at light intensities of either 53.8 or 166.4 1x in a 3 x 3 x 2 factorial arrangement of treatments. Light source during the growth phase had no significant effect on subsequent egg production, egg weight, fertility, or hatchability. Egg production, shell quality, fertility, and hatchability were also unaffected by light source or intensity during the breeder phase. Egg weight was significantly increased in hens exposed to HPSV compared with incandescent lights during the breeder phase. The HPSV and FL lights can be used effectively for turkey breeder hens both during the prebreeder and breeder periods. Furthermore, light intensities of 53.8 and 166.4 1x appear to be equally effective in stimulating production.

Animal Husbandry↗
PubMed2003

Daughters on request: about helpers and egg sexes in the Seychelles warbler.

The Seychelles warbler (Acrocephalus sechellensis) was an endangered endemic of the Seychelles islands where, until 1988, the entire population of ca. 320 birds was restricted to the one island of Cousin Island (29 ha). Additional breeding populations were successfully established on the islands of Aride (68 ha, 1988) and Cousine (26 ha, 1990) and now with the existence of ca. 2000 warblers on three islands the conservation status of the warbler has improved from endangered to vulnerable. Emigration from the island is extremely rare, so birds that disappeared were known to have died. Almost every bird on Cousin Island has been individually colour ringed and monitored throughout all breeding attempts during a 17-year period (1985-2002; total ca. 2400 birds). These birds were also blood sampled for molecular parentage and sex analyses. Therefore the lifetime reproductive success of many birds is known. Although warblers can breed independently in their first year, some individuals remain in their natal territory as subordinates, and often help by providing nourishment to non-descendant offspring. The frequency of 'helping' is affected by habitat saturation and variation in territory quality (insect prey availability). The long-term benefits of helping are higher for daughters than for sons, and it is therefore no wonder that most helpers are daughters from previous broods. Furthermore, on low-quality territories breeding pairs raising sons gain higher fitness benefits than by raising daughters, and vice versa on high-quality territories. Female breeders adaptively modify the sex of their single-egg clutches according to territory quality: male eggs on low quality and female eggs on high quality. The Seychelles warbler is a beautiful example of behavioural and life-history adaptations to restricted circumstances.

Animals↗
PubMed2005

Interaction between maternal effects and temperature affects diapause occurrence in the cricket Allonemobius socius.

The induction of diapause can be adaptive for egg survival during unfavorable conditions, while direct development can be advantageous under favorable conditions by allowing additional generations to exploit abundant resources. Therefore, the physiological capability of a female to respond to environmental cues indicative of habitat quality by producing eggs of the appropriate developmental phenotype should be under strong selection. Additionally, developing embryos may alter the developmental trajectory initiated by the female in response to changing environmental conditions. In this study, we used a cross-fostering approach to isolate the maternal effects of parental diapause history (not previously studied) and egg-laying temperature from the influence of the incubation environment experienced by the developing embryo on the proportion of diapause eggs produced by the striped ground cricket, Allonemobius socius. We found that an interaction between egg-incubation temperature and parental diapause history strongly affected the proportion of diapause eggs produced and the proportion of eggs that hatched within a 16-18 day incubation period, while egg-laying temperature and all other interactions did not. These novel results indicate that embryos can respond directly to the environmental conditions they experience during development, but that their ability to do so is influenced by maternal effects such as parental diapause history. The results of this study not only provide evidence, for the first time, of parental diapause history affecting diapause proportions, but also raise additional questions about the mechanism by which environmental information is transmitted from parent to offspring and how offspring are able to respond to conditions experienced during their own development.

Animals↗
PubMed2006

Multiple pathways of maternal effects in black-headed gull eggs: constraint and adaptive compensatory adjustment.

We investigated in the black-headed gull whether female deposition of antioxidants and immunoglobulins (enhancing early immune function), and testosterone (suppressing immune function and increasing early competitive skills) correlate suggesting that evolution has favoured the mutual adjustment of different pathways for maternal effects. We also took egg mass, the position of the egg in the laying sequence and offspring sex into account, as these affect offspring survival. Yolk antioxidant and immunoglobulin concentrations decreased across the laying order, while yolk testosterone concentrations increased. This may substantially handicap the immune defence of last-hatched chicks. The decrease in antioxidant levels was greater when mothers had a low body mass and when the increase in testosterone concentrations was relatively large. This suggests that female black-headed gulls are constrained in the deposition of antioxidants in last-laid eggs and compensate for this by enhanced testosterone deposition. The latter may be adaptive since it re-allocates the chick's investment from costly immune function to growth and competitive skills, necessary to overcome the consequences of hatching late from an egg of reduced quality.

Adaptation, Physiological↗
PubMed2003

Relation between tonic immobility and production estimated by factorial correspondence analysis in Japanese quail.

Duration of tonic immobility (TI) is a well-established criterion of fearfulness in birds, but its relation to production traits has been little studied. TI and 27 variables related to egg production and quality, feed consumption, and body condition were collected for 355 female Japanese quail. Experimental birds were the F2 generation from a reciprocal cross between a line selected for long TI and a line from a different origin and selected for early egg production. TI and several other variables had very asymetrical distributions so all variables were categorized, and the association between traits was studied by factorial correspondence analysis (FCA). Attributes of good versus poor layers were well separated by the FCA, but no association was obtained between TI and other traits on the primary axes of the FCA. Fearfulness, as measured by TI, was not related to levels of performance of egg laying quail. Secondary negative associations between TI and body temperature and between TI and residual feed consumption were obtained; however, they were marginal and need to be confirmed.

Animals↗
PubMed1995

TEST-yolk media and sperm quality.

Media prepared with egg yolk and two buffers, TES and Tris, called TEST-yolk have been shown to have beneficial effects on the survivability, fertilizing capacity and storage potential of human spermatozoa. Egg yolk lipoproteins are the critical compounds for the beneficial effects, with a synergistic effect due to the TES-Tris buffer component. TEST-yolk media have been used in the sperm penetration assay, the hemizona assay, sperm preparation for clinical in-vitro fertilization, artificial insemination with homologous spermatozoa, cryopreservation, sperm samples with a positive antisperm antibody test, and preparation for techniques requiring capacitated spermatozoa. Few harmful consequences of TEST-yolk have been reported, although controlled trials are required to evaluate therapeutic effects in the treatment of male infertility.

Cryopreservation↗
PubMed1991

Poultry production's environmental impact on water quality.

Poultry meat and eggs are rapidly becoming the major source of animal protein in the diets of American consumers. Such expansion has resulted in a similar increase in waste management problems. The national production of broilers and mature chickens was 5.68 billion, 242 million turkeys, 31 million ducks, and 69 trillion table eggs in 1989 based on the USDA National Statistics Survey. Annual production of fecal waste from poultry flocks was 8.8 million tons on a dry weight basis plus more than 106,000 metric tons of broiler hatchery waste. Add to this 37 million dead birds and condemnations at processing plants (figures are also from USDA for 1989 based on USDA National Statistics Survey). When all this waste is added together, the task of keeping the environment clean becomes monumental. The following waste management practices can and must take care of these poultry industry waste products: sanitary land fills, rendering facilities, extrusion machinery, compost plants, lagoons or holding tanks, and land application techniques.

Animals↗
PubMed1995

The use of feed restriction for improving reproductive traits in male-line white turkey hens. 2. Ovary morphology and laying traits.

The influence of feed restriction during rearing was investigated in male-line Large White breeder hens with regard to effects on ovarian morphology, egg production, laying patterns, and egg characteristics. Two hundred poults were reared from 4 to 28 wk of age under four treatments as follows: full-fed controls (FF), low-protein diet (12% CP from 12 to 28 wk; LP), and reduced BW (10 to 20% lower BW than FF; R10 and R20). At photostimulation (28 wk), all birds consumed a commercial breeder diet ad libitum for the remainder of the study (48 wk of age). Settable egg production (eggs per hen) to 48 wk for all hens, and those in lay was: FF, 39.4 (48.6); LP 42.7 (51.7); R10, 41.4 (52.8); R20, 40.7 (55.4). Inferior egg production per bird in R10 and R20 hens reflected a reduced persistency of lay. At first egg, hens of all treatments had a mean of 4.9 postovulatory follicles (POF) not accounted for by an egg. Number of unreconciled POF correlated with abdominal fat pad weight (P < or = .01). Ovary weight correlated with BW (P < .0001) and fat pad weight (P < .0004). Proportion of yolk and shell in the egg and egg specific gravity were improved with feed restriction. Sequence length was longest in R20 treatment hens and pause length shortest in R10 and R20 hens. Incidence of multiple-follicle sets was reduced in the R10 and R20 treatments. Feed restriction during rearing can potentially improve laying characteristics by altering ovarian morphology without limiting shell quality or yolk size. Quantitative feed restriction was most effective at improving egg quality, reducing average pause length, and reducing ovarian multiple-follicle sets. If problems with persistency of lay are addressed, the R10 and R20 treatments are the recommended rearing restriction treatments for male-line turkey breeder hen candidates.

Animals↗
PubMed1992

Leuprolide acetate-prepared in vitro fertilization-gamete intrafallopian transfer cycles: efficacy versus controls and cost analysis.

OBJECTIVE: To evaluate the effect of gonadotropin-releasing hormone agonist (GnRH-a) when given through stimulation with gonadotropins versus stopping it as stimulation was initiated versus a control group unprepared in this manner. Also, to construct a cost analysis for this type of therapy in an in vitro fertilization-gamete intrafallopian transfer program (IVF-GIFT). DESIGN: Prospective, consecutive, randomized, with a control group. SETTING: An out-patient IVF-GIFT program. PATIENTS: One hundred new patients entering an IVF-GIFT program. INTERVENTIONS: In vitro fertilization or GIFT cycles with or without preparation (pituitary suppression) by GnRH-a administration in which suppression was continued or halted as gonadotropins were begun. MAIN OUTCOME MEASURES: Cancellation rates, ampules, and days of gonadotropin use, costs, estradiol (E2) level, egg numbers and quality, and pregnancy rates. RESULTS: Stopping GnRH-a (leuprolide acetate) therapy as stimulation was begun did not lessen the suppressive effect in reduction of spontaneous luteinizing hormone surge as seen with continued use of agonist. In contrast, the control group had a 30.3% cancellation rate before ovum retrieval. The E2 and egg data among the groups were similar, but as expected, agonist use led to the need for more and longer duration of gonadotropin stimulation. Pregnancy rates were not different by group. Costs were approximately even by the third initiated cycle.

Adult↗
PubMed2003

Impurity effects on lysozyme crystal growth.

Atomic force microscopy (AFM) and X-ray diffraction experiments have been combined to study the correlation between impurity incorporation, crystal surface morphology and crystal quality. Hen egg-white lysozyme has been used as a model protein, and covalently bound lysozyme dimer as a model impurity. AFM observation of the [101] crystal face revealed that the crystal surface clearly became rough when 5% impurity was added, and the steps disappeared as the impurity concentration increased to 10%. The crystal quality was evaluated by four factors: maximum resolution limit, / , Rmerge, and overall B factor. In every index, the crystal quality tended to degrade as the impurity concentration increased. The B-factor dropped significantly at 5% impurity; at the same time the step roughening was observed. This strongly suggested that the impurity incorporation affected the step growth mechanism and degraded the crystal quality.

Crystallization↗
PubMed2004

Protein quantity, not protein quality, accelerates whole-body leucine kinetics and the acute-phase response during acute infection in marasmic Malawian children.

The present study compared leucine kinetics and acute-phase-protein concentrations in three groups of marasmic, acutely infected Malawian children fed one of three isoenergetic diets. These were: an enhanced-protein-quality diet (egg-white+tryptophan, providing 1.2 g protein/kg per d; n 14); an increased-protein-content diet (egg-white+tryptophan, providing 1.8 g protein/kg per d; n 14); a standard-protein diet (1.2 g milk protein/kg per d; n 25). The hypotheses tested were that children receiving a diet with more protein would have greater rates of non-oxidative leucine disposal and that children receiving an isonitrogenous diet with a higher protein quality would have lower rates of leucine oxidation. The children were studied after 24 h of therapy using standard [(13)C]leucine stable-isotope tracer techniques. The children receiving the higher-protein-content diet had greater leucine kinetic rates than those receiving the standard-protein-content diet; non-oxidative leucine disposal was 170 (sd 52) v. 122 (sd 30) mumol leucine/kg per h (P<0.01). Leucine oxidation was less in the children receiving the enhanced-protein-quality diet than in those receiving the standard-protein-quality diet; 34 (sd 12) v. 45 (sd 13) mumol leucine/kg per h (P<0.05). The children receiving the high-protein-content diet increased their serum concentration for five of six acute-phase proteins 24 h after starting therapy, while those receiving the standard-protein-content diet did not. These data suggest that there was greater whole-body protein synthesis, and a more vigorous acute-phase response associated with the higher-protein-content diet. The clinical benefits associated with a higher protein intake in marasmic, acutely infected children need further study.

Acute Disease↗
PubMed1989

[Embryo transfer in swine in relation to a gene transfer program].

The production of the recommended embryonic stage for microinjection of foreign DNA into pronuclei needs a precisely timed preparation of donor pigs. For oestrus induction 1250 IU of PMSG is used at a body weight of 60 kg to 90 kg. To induce ovulation 750 IU of HCG are injected 3 days later. After two inseminations eggs are collected by surgical flush of the oviducts and centrifuged for 3 min at 15,000 g for visualization of the pronuclei. After DNA-microinjection the embryos are transferred to 12 h asynchronous recipients. About 50% of the collected eggs could be used for our experiments. The number and quality of the recovered eggs was related to the body weight of the donors. An in vivo culture system in the non-ligated pig oviduct was established in order to measure the effects of the distinct steps in microinjection on embryo survival. The survival rate of untreated zygotes was 52%. After centrifugation the rate was reduced to 38% and after microinjection to 12%. Pregnancy rate after 98 transfers was 37% and an average of 3.9 piglets were born per litter.

Animals↗
PubMed1996

Changes in serum triiodothyronine, thyroxine, estradiol-17 beta, progesterone levels and egg production in hypocholesterolemia induced Japanese quails Coturnix coturnix japanica.

Mature healthy female Japanese quails injected (i.p.) with gemfibrozil at two dose levels for 1,2,3 and 4 weeks induced hypocholesterolemia as observed by the serum cholesterol concentration which was more severe with the higher dose. Liver and ovarian cholesterol contents decreased in 3rd and 4th week of the treatment. Significant (P > 0.05) increase in serum triiodothyronine (T3) and thyroxine (T4) level were observed between 3rd and 4th week while serum estradiol-17 beta and progesterone levels declined continuously from Ist week till the termination of the treatment. The quantity and quality of the eggs produced by the treated quails were inferior. These results indicate that induction of hypocholesterolemia impaired the reproductive efficiency of quails.

Animals↗
PubMed2003

Comparison of peanut meal and soybean meal as protein supplements for laying hens.

Peanut protein is severely limiting in threonine and has been used to create threonine deficiency in animals. The availability of purified threonine at low cost raises the possibility of economically using peanut meal (PNM) and threonine combinations in poultry diets. An experiment was conducted to compare corn and PNM based diets to corn and soybean meal (SBM) based diets at three protein levels (16, 18.5, and 21%) in diets for 22-to-34-wk-old commercial Leghorns. Birds were housed two per cage with four cages per replicate and six replicates per treatment. Feed consumption, egg production, and feed per dozen eggs were almost identical for PNM (93.8 g/hen per d, 92.2 eggs per 100 hens/d, and 1.22 kg/dozen) and SBM (93.7 g/hen per d, 92.2 eggs per 100 hens/d, and 1.22 kg/dozen). Dietary protein level had no consistent effect on any of these parameters but did significantly improve body weight gains and egg weights (1.2 to 2.5 g/egg). PNM-fed hens laid slightly smaller eggs during the first 6 wk (P<0.05), but there were no egg size differences during the last 6 wk of the experiment (P>0.14). PNM-fed hens laid eggs with better interior quality at 26 and 30 wk of age. After 2 wk of storage, Haugh units remained better for eggs from hens fed PNM than SBM when kept refrigerated (4 degrees C; P<0.05) or at room temperature (20 degrees C; P<0.10). Egg specific gravity was slightly lower for hens fed PNM. It is concluded that PNM is an excellent ingredient for laying hen diets.

Animal Feed↗