Viable Chicks Research Articles

Chemerin concentration in egg white in layer and broiler hens during the laying period for 2 successive generations

The genetic selection progress in layers and broilers makes poultry production one of the fastet growing industries. Objectives of the breeding companies are the stability or the increase in the laying rate and the production of viable chicks. New biomarkers are necessary to improve reproductive and egg performances. Chemerin (Chem) produced by oviduct accumulates in egg white (EW). Here, we hypothesized that EW Chem concentration was dependent on the stage of laying and on the breed (layer vs broiler). In addition, they could be associated to laying performance and fertility parameters. In breeding companies, we collected during two successive generations (G0 (mother) and G1 (daughter)) eggs from 100 layers and 100 broilers hens during five days at three stages: before, after laying peak and at the end of laying period. For each egg, the EW was sampled to measure Chem concentration by ELISA assay. In each generation at the end of laying period, magnums from oviduct, where the EG is formed, were collected in layers and broilers in order to investigate Chem differential expression by RT-qPCR between both breeds. Chem concentration in EW was dependent on the time of laying period and its profile was differently regulated in layers and broilers. Indeed, it increased at the end of laying in layers whereas it decreased after the laying peak in broilers. At the end of laying period, Chem concentration in EW was almost two-fold higher in layers than in broilers and this was confirmed in both G0 and G1 generations at the Chem mRNA and protein levels in the magnum. For the two successive generations, Chem concentration in EW was negatively correlated with the laying rate and the fertility parameter in broiler hens whereas it was negatively correlated with the egg quality (weight of whole egg and weight of albumen) and positively with the fertility rate at some time of laying in layer hens. Taken together, the Chem concentration in EW could be a potential predictive tool for reproductive parameters in genetic selection.

Effect of in ovo feeding using albumin to Rhode Island Red poultry embryos

This study aimed to evaluate the effects of in ovo feeding using albumin on hatchability, hatching weight, embryo mortality, as well as on organ development of Rhode Island Red chicks. A total of 245 fertile eggs with viable embryos were randomly distributed in seven treatments with 35 replicates (eggs) each. The treatments were untreated eggs and eggs treated with a buffered solution (0.50% saline) or solutions containing increased levels of albumin (0.5, 1.0, 1.5, 2.0, and 2.5%). On d 17 of incubation, eggs were injected with solutions containing albumin dissolved in 200 μL of 0.5% sterile saline. After solutions injection, the pinholes in the eggs were sealed with molten paraffin and moved to a hatching machine. Evaluation of the chicks’ weight, hatchability, and embryo mortality was made immediately post hatch. Five viable chicks of each treatment were randomly selected and slaughtered by cervical dislocation in order to evaluate the heart, gastrointestinal organs and region development. Data collected were subjected to polynomial regression (p≤0.05) after a significant ANOVA result. In ovo feeding using albumin directly affected (p<0.05) the hatching characteristics of injected eggs. When eggs were injected with increased levels of albumin, there was a linear decrease (p<0.05) on hatchability and increase on embryo mortality. The increased supplementation of albumin resulted in a linear growth (p<0.05) of gastrointestinal tract areas responsible to digestion (oropharynx + oesophagus, duodenal loop and cecum), and a linear decrease of heart, liver, pro-ventricle, gizzard and gastrointestinal tract areas responsible to absorption (jejunum + ileum and colon + rectum).

Effect of housing system and housing density on performance, viability, and gastrointestinal tract growth of broiler chicks during the first 2 wk of age

This experiment was conducted to study the effect of housing systems and housing densities on the performance and digestive tract growth of broiler chicks during the first 2 wk of age. A total of 3,600 Cobb500 day-old chicks were stocked at 4 densities (30, 60, 90, and 120 chicks/m2), and reared under 2 housing systems (conventional housing system and newly developed housing system), yielding a 2×4 factorial arrangement. The studied traits were performance, viability, and gastrointestinal tract development. The results indicated that housing systems and housing densities significantly (P < 0.001) affected the performance and GIT development of chicks. There were no significant interactions between housing system and housing density for body weight, body weight gain, feed intake, and feed conversion. The results also showed that the effects of housing density were age-dependent. That is, the higher the density, the lower the performance and digestive tract growth with advancing age. In conclusion, birds in the conventional system outperformed birds in the newly developed housing system, and further work is needed to improve the new housing system. To achieve the highest performance, digestive tract growth, and digesta content, a density of 30 chicks/m2 is recommended for chicks up to 14-days old.

Effect of a commercial product containing canthaxanthin for in ovo feeding to broiler embryos on hatchability, chick quality, oxidation status, and performance

In ovo feeding has been indicated to improve hatchability, newly hatched chick quality, and broiler performance. The aim of this study was to investigate the effect of in ovo feeding of a commercial canthaxanthin product (CCX) containing lignosulphonate, corn starch, canthaxanthin, dextrin (yellow), and ethoxyquin through assessing incubation results, newly hatched quality and oxidation status and broiler performance at 1 to 14 d of age. A total of 780 egg were distributed in a randomized complete block design with 5 treatments (levels of CCX: 0.0, 0.35, 0.45, 0.55, and 0.65 mg/0.5 mL of sterilized and distilled water) and 156 eggs per treatment. The blocking factor was setters. At 17.5 d of embryo development, in ovo injected treatments were applied, using a manual needle. The in ovo feeding of CCX resulted in lower hatching rates (P < 0.05) and a longer hatching window (P < 0.05) as compared with noninjected CCX treatment. The CCX injection did not affect the bursa and spleen percentage of newly hatched chick (P > 0.05). In addition, a higher percentage of chicks with poor physical quality score (<71.0 points) was obtained among the chicks from eggs injected with 0.55 and 0.65 mg of CCX (P < 0.05). There were higher total proteins and catalase activity in the livers of the chicks injected with CCX. Broiler chicks in the control group (0.0 mg of CCX) presented higher BW and BW gain during 1 to 7 and 7 to 14 d of after hatch (P < 0.05). The viability (%) of chicks at 1 to 14 d of after hatch decreased with inoculation greater than 0.45 mg of CCX in ovo (P < 0.05). Although the CCX shown an improvement in oxidation status of chicks, the hatchability and performance of broilers decreased. We concluded that a commercial CCX is not recommended for injection in ovo, and furthers studies should carried out to elucidate the use of pure canthaxanthin.

A grape seed extract maternal dietary supplementation in reproductive hens reduces oxidative stress associated to modulation of plasma and tissue adipokines expression and improves viability of offsprings.

In reproductive hens, a feed restriction is an usual practice to improve metabolic and reproductive disorders. However, it acts a stressor on the animal. In mammals, grape seed extracts (GSE) reduces oxidative stress. However, their effect on endocrine and tissue response need to be deepened in reproductive hens. Here, we evaluated the effects of time and level of GSE dietary supplementation on growth performance, viability, oxidative stress and metabolic parameters in plasma and metabolic tissues in reproductive hens and their offsprings. We designed an in vivo trial using 4 groups of feed restricted hens: A (control), B and C (supplemented with 0.5% and 1% of the total diet composition in GSE since week 4, respectively) and D (supplemented with 1% of GSE since the hatch). In hens from hatch to week 40, GSE supplementation did not affect food intake and fattening whatever the time and dose of supplementation. Body weight was significantly reduced in D group as compared to control. In all hen groups, GSE supplementation decreased plasma oxidative stress index associated to a decrease in the mRNA expression of the NOX4 and 5 oxidant genes in liver and muscle and an increase in SOD mRNA expression. This was also associated to decreased plasma chemerin and increased plasma adiponectin and visfatin levels. Interestingly, maternal GSE supplementation increased the live body weight and viability of chicks at hatching and 10 days of age. This was associated to a decrease in plasma and liver oxidative stress parameters. Taken together, GSE maternal dietary supplementation reduces plasma and tissue oxidative stress associated to modulation of adipokines without affecting fattening in reproductive hens. A 1% GSE maternal dietary supplementation increased offspring viability and reduced oxidative stress suggesting a beneficial transgenerational effect and a potential use to improve the quality of the progeny in reproductive hens.

Reproductive Characteristics of Cockatiels (Nymphicus hollandicus) Maintained in Captivityand Receiving Madagascar Cockroach (Gromphadorhina portentosa) Meal.

Simple SummaryThis research article describes the effects of including a Madagascar cockroach meal in the feed of cockatiels on their reproductive characteristics. The cockatiel is one of the most common species of the Psittaciformes order adopted as a pet and, despite this, information on the reproductive characteristics of this species and how nutrition can influence these characteristics is still scarce. However, the evaluation of this ingredient in the feed of cockatiels has not yet been performed. We observed that the inclusion of a cockroach meal in the feeds of cockatiels increased the number of viable chicks with 1 day of life, decreased the number of days for new laying, increased egg width and shape index, and influenced its lipid composition. Therefore, the present study provides important information about an alternative protein ingredient that can assist researchers and breeders in the management of these birds, ensuring better health for the animals as well as gains in productivity.The aim of this study was to evaluate the use of a Madagascar cockroach (Gromphadorhina portentosa) meal in the feed of cockatiels (Nymphicus hollandicus) in captivity and its influence on the reproductive characteristics of these birds. Twelve pairs of birds were used during two subsequent reproductive cycles of 130 days each, with time divided into four phases: laying, incubation, rearing of chicks until 30 days of age, and return to the new laying phase. The pairs were divided into two groups: a control group, which received a commercial diet for psittacines + a mixture of seeds, and a test group, which received the same diet as the control group except for the addition of a Madagascar cockroach meal in a ratio of 14 g of commercial food to 1 g of cockroach meal (6.6%). After hatching, chicks remained with their parents until 30 days of age. Subsequently, the chicks were transferred to another room and monitored until the 90th day of life. The inclusion of cockroach meal did not influence (p > 0.05) the intake of commercial food and mixture of seeds during the reproductive phases evaluated, except for feed intake, which was increased relative to control values (p = 0.02) in the return-to-laying phase. Yolk cholesterol content, egg width and egg shape index were increased with the inclusion of the cockroach meal, whereas the number of days to return to the new laying phase was reduced compared to the control (p = 0.02). The number of eggs laid decreased (p < 0.05) with the inclusion of the cockroach meal; however, the percentage of hatching was higher in the test group than in the control group (p < 0.05). No significant effect (p > 0.05) of dietary treatment was observed on the number of viable chicks at 1, 30 and 90 days of age or on the contents of most fatty acids present in the yolk. The findings of this study indicate that a Madagascar cockroach meal can be used as an alternative feedstuff in the diets for cockatiels and can lead to minor improvements in reproductive characteristics when replacing 6.6% of the commercial pelleted diet.

Nest defense behavior of Greater Roadrunners (Geococcyx californianus) in south Texas

The Greater Roadrunner (Geococcyx californianus) is a medium-sized predatory bird that occurs widely across the southwestern United States. Despite its prevalence in this region, studies examining the nesting and behavioral ecology of this species are limited. In 2015 and 2016, we examined relatively unknown aspects of roadrunner natural history by using infrared video cameras to observe antipredator behaviors associated with Greater Roadrunner nest defense. Nest predation accounted for all nesting failures in our study. The Great Plains rat snake (Pantherophis emoryi) accounted for 70.0% of nest predation. We observed rat snakes entering the nest and consuming eggs or nestlings for >6 min before roadrunners flushed from nest sites. We also observed 53.3% of roadrunners actively defending nest sites from snake predators and zero defending nests from coyotes (Canis latrans), likely because of the predator size. Active defense sessions in our study lasted 1 min 20 s (95% CI 1 min 17 s) and consisted of 12.0 (95% CI 3.4) bill strikes per min of active defense. We observed no successful nest defenses because partial nest contents were lost during each event; however, >50% of predation events with an active defense session resulted in preservation of at least one viable egg or chick, indicating nest defense was a valuable behavior. Examining nest defense behaviors in larger, predatory birds may elucidate risks and rewards associated with nest defense that may not be observed in studies focusing primarily on passerines.

Inclusion of canthaxanthin and 25-hydroxycholecalciferol in the diet of broiler breeders on performance and incubation parameters

The objective of this experiment was to evaluate the effects of a diet containing canthaxanthin and 25-hydroxycholecalciferol (25-OH-D3) on the production and reproductive performances of Cobb 500 broiler breeders aged 53 to 61 weeks. The study included 36,000 Cobb 500 female and 3,600 male broiler breeders aging 51 weeks. The birds were housed in three poultry houses divided into four plots, totaling 12 experimental units each containing 3,000 females and 300 males. The birds received the following treatments: control diet (without the studied additives) or the control diet with the addition of 60mg kg-1feed of 25-(OH)-D3 and canthaxanthin feed (6mg of canthaxanthin and 2,760,000IU of 25-(OH)-D3 per kg of feed) per the supplier's recommendations. The experimental design used was a randomized complete block design with two treatments and six replicates. The results were subjected to analysis of variance followed by the F-test. The treatments had no effect on egg production, usability of eggs and number of incubatable eggs per bird housed. The inclusion of canthaxanthin and 25-(OH)-D3 in the diet reduced embryonic mortality while increasing egg yolk pigmentation, hatching percentage, and number of viable chicks produced per bird. Therefore, the use of 60mg kg-1of 25-(OH)-D3 plus canthaxanthin is recommended in the diet of Cobb 500 broiler breeders aging 53 to 61 weeks to improve important reproductive traits that have great economic impacts on poultry farms

Evaluation of egg quality traits in a synthetic coloured broiler female line

Coloured broiler breeders are becoming popular in recent years because of the preference for a range of poultry products as well as the welfare issues in the poultry industry. The female broiler breeders are continuously improved for various economic traits. Amongst these, egg quality trait is very essential for the production of healthy and viable chicks. This study investigates the egg quality parameters in a synthetic coloured broiler breeder female line at different age groups. The study revealed that the egg quality is optimum for setting the eggs for hatching from 40 week onwards as the egg size and internal egg parameters attain the minimum standards for the production of a healthy chick.

NATURAL ANTIOXIDANTS IN HENS' EMBRYOGENESIS AND ANTISTRESS DEFENCE IN POSTNATAL DEVELOPMENT (review)

The success of modern broiler industry is closely associated with breeding programs aimed at production of broiler chickens that show fast growth, high production yield, and efficient conversion of feed. These features of broilers often interfere with their health – as a rule, the higher is productivity, the more is birds’ susceptibility to various stresses, which poses a certain problem for breeding work (1). From a fertilized egg cell to farm housing of chicks, there are various factors (quality of incubation eggs, egg storage conditions, incubation technology, conditions in the period between hatching and delivery to a farm), and their interaction notably affects productivity of reared broilers. In general, all of these factors are significant determinants of the quality of chicks (2). In contrast to mammals, avian embryogenesis occurs in an egg, the semi-closed system with only exchange of gases and water. Today it’s a certainty that successful embryonic development of a chick depends on egg composition and conditions of incubation. Many facts from the available literature show that maternal diet is the main determinant of health and development of offspring in avians, as well as in humans and other mammals. Egg composition is such that it contains in yolk and albumen all the nutrients necessary for the development of future embryo (3). Polyunsaturated fatty acids (PUFA) and natural antioxidants of maternal diet are key important for the development of chick embryos and viability of chicks in early post-hatch period. Indeed, high content of endogenous antioxidants in the egg and embryonic tissues may be a major adaptive mechanism preventing the oxidative stress at hatching. Free radicals: formation, biological functions and control. Free radicals are atoms, or molecules of any compounds containing unpaired electrons (one or more). Most of biologically important free radicals are formed in the presence of oxygen and nitrogen – activators of this process. Both these elements play a significant role in metabolism of human and animals, but under certain conditions they may pass (directionally or randomly) into the molecules of free radicals. Free radicals are highly unstable and very reactive; they can damage DNA, proteins, lipids, carbohydrates, and disrupt cell signaling system (4). DNA damage is associated with mutations, errors of genetic data transfer, impaired protein synthesis, and, in some cases, it leads to cancer. Protein damage causes disorders of ion transport, functioning of receptors, and it changes properties of certain most important enzymes. The oxidation of PUFA in cell membranes affects their structure and properties (fluidity and permeability, etc.), and the activity of membrane-bound enzymes. Damage to biological molecules causes a notable negative effect on growth, development, reproduction, and immunocompetence. In general, for the last three decades the study of free radicals and their adverse effects on biomolecules was mainly focused on lipid peroxidation as a basis of the observed adverse effects. The modern trend of such researches is associated with negative effects of free radicals on proteins and DNA (5, 6). Cells are permanently attacked by free radicals, most of which are elements of a normal metabolism, or the agents of immune response in phagocytes that destruct microbes-invaders. Under normal physiological conditions, about 3-5% of the oxygen utilized by cells and passed to the mitochondrial electron-transfer chain, may leave it to be converted into free radicals (7). In rats, each cell has to process daily about 10 12

Developmental and behavioral effects of medetomidine following in ovo injection in chicks

Developmental and behavioral effects of medetomidine were assessed in chicks following in ovo exposure on incubation day 4. Medetomidine at 25 and 50μg/egg injected once into the air cell on incubation day 4, dose-dependently decreased the number of viable chick embryos starting on day 10 of the incubation. The percentages of successful hatching in the control and medetomidine treated groups were 93, 60 and 47%, respectively. Embryo lethalities in these groups were 7, 40 and 53%, respectively. In ovo exposure of the chicks to medetomidine at 25 and 50μg/egg did not significantly affect the body weight of the chicks as well as their morphometric measurements. In another experiment, 3- and 8-day old chicks exposed to medetomidine in ovo (25μg/egg) were monitored in the open-field for 5min. Medetomidine suppressed the open-field activity of both 3- and 8-day old chicks. This was manifested by a significant increase in the latency to move from the central square of the open-field arena and a decrease in the number of lines crossed (ambulation) with an additional decrease in vocalizations of the 3-day old chicks when compared with respective age-matched control values. In the same medetomidine-exposed chicks the duration of tonic immobility significantly increased in comparison with respective control values. Pharmacological challenge of the medetomidine-exposed chicks (8-day old) with medetomidine at 25μg/kg, intramuscularly significantly increased the latencies to onset of sedation and loss of righting reflex and decreased the duration of sleep when compared with the saline-control group challenged in the same manner. The data suggest that medetomidine could be a behavioral teratogen in chicks following in ovo exposure.

Early nutritional strategies

The embryonic and immediate post-hatch developmental period represents a significant phase in attaining quality broiler performance at marketing. An efficient transition period from late term embryo to a viable independent chick is necessary to achieve such results. Immediately, post-hatch birds must undergo a shift from egg and embryonic nutrients to exogenous feed. Under practical conditions, many birds have access to feed only 36 to 48 hours after hatching, and during this time body weight decreases, and intestine and muscle development are retarded. In order to overcome these limitations, a continuous feeding process can be established which would supply nutrients to the developing embryo, feed and water to the newly hatched chick within the hatchery, and a highly digestible pre-starter diet at placement. In ovo feeding stimulates intestinal development by enhancing villi, increasing intestinal capacity to digest and absorb nutrients and provides a basis for muscle growth. Immediate access to feed (1 hour after clearing the shell) initiates uptake and growth processes some 24 hours post-ingestion compared to poultry with delayed feed intake. The enhanced growth caused by early feeding improves nutritional maturity of the bird, stimulates yolk utilisation, increases intestinal development, and has long term metabolic effects. Providing highly digestible ingredients in the pre-starter diet increases body weight performance at day seven, and through to marketing. Together, these processes provide appropriate nutrition pre- and post-hatch which can accelerate gastrointestinal development, muscle growth and therefore result in increased performance. This paper will summarise studies dealing with the different approaches to early nutritional strategies in our modern, fast growing broiler.

Use of Ribav and succinate for stimulating natural resistance of chicks at different stages of ontogeny

The aerosol use of Ribav before incubation and succinic acid on the 19th day of incubation of eggs leads to optimizing metabolic processes in embryos, which promotes an increase of viability of chicks both in early and late stages of embryogenesis.

The Hygienic Monitoring for Chicken Hatcheries in Taiwan during 2002-2007

Microorganism contamination in hatchery and eggs has a serious impact on the viability and quality of chicks as well as on the overall growth performance of chickens. Microbiological agents are present in the fluff when the chicks hatch. Detecting microorganisms in fluff is a convenient method for evaluating the hygienic status in a hatchery. Fluff samples from 18-23 hatcheries were tested for the total bacterial count, the presence of Salmonella spp., and fungus to evaluate the hygienic status of hatcheries in Taiwan from 2002 to 2007. The total bacterial score (BS) from the fluff samples was calculated and expressed as a log scale. Most hatcheries had a BS that ranged from scale 1 to 2. Salmonella contamination more than three quarters in a year was found in 3 hatcheries. Two of them closed after then. Five hatcheries were contaminated with fungus for more than three quarters in a year. According to the data obtained from the fluff test, hatcheries keep their hygienic status by cleaning and disinfecting the hatchery and supply chicks in good quality.

Chicken embryo utilization of egg micronutrients

IntroductionAvian embryos develop and grow from energy and nutrients storedin the egg by the hen. In this sense, breeder male contribution is notimportant. Follicular deposition of nutrients occurs over a wide range oftime, but becomes relevant during the week prior to ovulation. Amounts,but also forms, of nutrients deposited in the egg determine success ofembryo development and hatching of a healthy chick. To support theembryo during incubation, oxygen is the only nutrient not derived fromthe egg; however, adequate oxygen concentrations in the surroundingair and its free passage through well-established shell membraneporosities are essential. Developmental limitations and embryo mortalityare aggravated when any inadequacy in these conditions prevail.Macroscopically, the fertile egg has three components: shell, yolk,and albumen. Specific nutrients are mobilized by the embryo from eachof these parts. These typically have expected compositions, which arenotably affected by the hen’s nutrition.After oviposition, the egg may be submitted to changes due to inovo injection using the vaccination equipment routinely used inhatcheries. However, these injections are limited to small amounts, andpreferably done with more available forms of micronutrients. Researchon this matter is recent and usually directed to metabolic interventions,such as the role of substances which stimulate or mediate enzymetranscription.Egg ReservesMacroscopically, the egg is a simple structure with three majorcomponents (shell, albumen, and yolk), demonstrating uniquecharacteristics and playing specific roles during incubation. It is generallyagreed that each egg is built with a complete capacity to produce aperfect new organism. However, due to several reasons, this is notalways the case. In general, the composition of macromolecules in eggsis more constant than those elements usually found in a lower proportion,such as micronutrients. Since all egg constituents derive from the hen’sorganism, metabolic transformation of the hen’s feed is needed toobtain adequate embryo development and viable chicks at hatching.Egg shells consist of two main components: a matrix of protein fibersand col umns of calcium carbonate crystals in a proportion of 1:50 (Romanoff& Romanoff, 1949). A glycoprotein layer, the cuticle, covers the crystalsurface, and it is the last egg component to be deposited before oviposition.The cuticle has three main functions: prevention of excessive water loss(Peebles & Brake, 1986), protection from microbial infection (Roussel et al.,1988), and termination of calcite crystal growth (Dennis et al., 1996). Theshell matrix presents two regions: a mammillary region, connected to theouter shell membrane protein fibers, and a spongy one, associated to calcitecrystals deposited in layers on the mammillary matrix (Simkiss, 1968).

Vitellogenin detection and chick pathology are useful endpoints to evaluate endocrine‐disrupting effects in avian one‐generation reproduction study

To investigate additional endpoints for screening of endocrine disruptors in birds, effects of 17beta-estradiol (E2) on one-generation reproduction in the Japanese quail (Coturnix japonica) were assessed. Pairs of the 10-week-old Japanese quail were fed a low-phytoestrogen diet containing E2 at 0 (control), 10, 100, and 1,000 ppm for six weeks. In the E2 100- and 1,000-ppm groups, the parental quail represented marked toxic changes including high mortality, decreased food consumption, decreased gonad weights, gross and histologic toxic changes in the reproductive and other organs, and inhibition of the reproduction. However, no adverse effects were observed in the parental quail from the E2 10-ppm group. In the parental males, serum vitellogenin (VTG) concentrations were increased significantly in the E2 10-ppm group, disclosing that serum VTG concentration is one of the highly sensitive endpoints for evaluating estrogenic endocrine activities. In the E2 10-ppm group, number of eggs laid, number of eggs with abnormalities, eggshell strength and thickness, fertility, early and late viabilities of embryos, normal hatchling rate, and clinical signs, mortality, viability, and body weight of chicks at 14 d of age were not affected. However, histopathology of the chicks in the E2 10-ppm group revealed meaningful morphological changes in the reproductive organs, such as cystic dilatation of seminiferous tubules, increased interstitial cells in the testis, and decreased theca cells in the ovary. The present study suggests that serum VTG concentration in the parental quail and histopathology of reproductive organs in the offspring are sensitive endpoints and are useful as additional endpoints in the avian one-generation reproduction test using the Japanese quail for evaluating estrogenic endocrine-disrupting effects.

Main characteristics of biological components of developing life support system observed during the experiments aboard orbital complex MIR.

Since 1990, the orbital complex MIR has witnessed several incubator experiments for determination of spaceflight effects on embryogenesis of Japanese quail. First viable chicks who had completed the whole embryological cycle in MIR microgravity hatched out in 1990; it became clear that newborns would not be able to adapt to microgravity unaided. There were 8 successful incubations of chicks in the period from 1990 to 1999. In 1995-1997 the MIR-NASA space science program united Russian and US investigators. As a result, experiments Greenhouse-1 and 2 were performed with an effort to grow super dwarf wheat from seed to seed, and experiment Greenhouse-3 aimed at receiving two successive generations of Brassica rapa. But results of these experiments could not be used for definitive conclusions concerning effects of spaceflight on plant ontogenesis and, therefore, experiments Greenhouse-4 and 5 were staged within the framework of the Russian national space program. The experiments finally yielded wheat seeds. Some of the seeds was left on the space station and, being planted, gave viable seedlings which, in their turn, produced the second crop of space seeds.

Incubabilidade e Qualidade de Pintos de Ovos Matrizes de Frangos de Corte Submetidos a Estresse de Temperatura

O experimento foi conduzido para avaliar o efeito do estresse de temperatura sobre as características de incubabilidade e qualidade dos pintos nascidos. Trezentos ovos, obtidos de um lote de matrizes de frangos de corte com 42 semanas, foram distribuídos em três incubadoras, reguladas para manter uma temperatura de 37,8ºC, umidade relativa de 60% e viragem mecânica a cada duas horas. Aos 16 dias de incubação (D16), aplicou-se uma variação de temperatura de calor (40ºC) ou frio (32ºC) durante cinco horas em duas máquinas. Os embriões da terceira máquina foram usados como controle. Os dados obtidos foram analisados estatisticamente, obedecendo-se a um delineamento inteiramente casualizado, com 3 tratamentos. A eclodibilidade e a qualidade dos pintainhos, avaliados pelo peso ao nascer e qualidade de pernas e umbigo não foram significativamente diferentes entre o grupo controle e os grupos estressados. Os resultados revelaram que os ovos exposto ao estresse pelo frio ou calor tiveram um período de incubação maiores - 506,5h e 504,2h, respectivamente - do que aqueles expostos a temperatura normal - 496,3h - como conseqüência no atraso de bicagem interna (7 e 6 h) e externa (13 e 14 h). Concluiu-se que a alteração da temperatura normal de incubação, com resfriamento ou aquecimento por 5 h no D16, não foi suficiente para prejudicar a eclodibilidade e a qualidade dos pintainhos, mas causou uma dilatação do período total de incubação, indicando que mesmo um breve período de variação da temperatura normal de incubação em um período crítico de desenvolvimento é suficiente para determinar estresse nos embriões de frangos de corte.

An impact of genetic variation and predation on chick survival in willow ptarmigan Lagopus l. lagopus

The present study investigates the determinants of chick survival in willow ptarmigan Lagopus l. lagopus. Chick survival was negatively associated with genetic relatedness of mates. This may imply that more chicks die when genetic relatedness of mates is high, i.e. low chick heterozygosity at hatching. Hence, newly hatched chicks with low heterozygosity may have reduced viability and, therefore, might suffer higher mortality due to biotic/abiotic conditions. However, there was no association between the proportion of chicks with low heterozygosity and ambient temperature, but a highly significant association with predation pressure was found. Because newly hatched chicks are unable to maintain their body temperature even at normal ambient temperatures and because willow ptarmigan chicks start chirping when they get cold, it is suggested that chicks with low genetic variation may become more exposed to predation. It is proposed that genetic variation significantly affects viability of ptarmigan chicks, but that predation is the proximate cause of death. Consistent with several earlier studies, predation was related both to nesting females and to survival of the chicks. However, the present study extends these findings by suggesting a relationship between predation on one side and genetic constitution on the other, and that predation on nesting females, by reducing genetic variation among chicks at hatching, enhance chick mortality.

Examination of the Dietary Methionine Requirements of Breeding Northern Bobwhite, Colinus virginianus

Adult Northern bobwhite were used to test the hypothesis that dietary methionine levels recommended by the NRC for breeding quail are excessive for wild bobwhite. We tested the hypothesis by comparing immunocompetence, reproductive performance, and chick viability of Northern bobwhite hens fed diets containing low (0.31%), moderate (0.39%), or high (0.47%) concentrations of methionine. Chick viability was determined by assessing immunocompetence, including evaluating the ability of hens to passively transfer immunity to their chicks. Hens were fed the experimental diets for 6 wk on an ad libitum basis. After 6 wk, methionine treatment had no measurable effect (P ≥ 0.20) on hen phytohemagglutinin wing web indices, organ weights, or serum anti-Pasteurella multocida titer indices. Mean egg weight, percentage egg production, total cumulative egg production, yolk weight, yolk volume, and percentage fertile and percentage hatch of fertile eggs did not differ (P ≥ 0.12) among diet treatments. Amount of albumen in eggs produced by hens fed the high methionine diet averaged 0.27 g more (P = 0.003) than eggs of hens fed the low methionine diet. Anti-P. multocida titer of yolks from eggs in Week 6 were not different (P = 0.36) between birds fed the high and the low methionine diets. The mortality rate of chicks after challenge with 23 cfu of P. multocida was not different (P ≥ 0.05) among diets. Chicks hatched from eggs laid by vaccinated hens during Weeks 2 and 3, however, had lower (P < 0.05) mortality than chicks of unvaccinated hens. It appears a dietary methionine concentration of 0.3% may be sufficient for wild Northern bobwhite to produce viable chicks.