Early Chicks Research Articles

In vitro study of corticotropin-releasing hormone-induced thyrotropin release: ontogeny and inhibition by somatostatin

Recent research has shown that in the chicken important interactions take place between the adrenal and the thyroidal axis both at the central and the peripheral level. In vivo as well as in vitro experiments showed that ovine corticotropin-releasing hormone (oCRH) clearly increases thyrotropin (TSH) secretion in late embryonic and early posthatch chicks. In vivo experiments in older chickens, however, suggested that this response might disappear at a later stage. Therefore we started to study in detail the ontogeny of the TSH releasing activity of oCRH using the in vitro perifusion technique. Several embryonic stages (E14, E16, and E18) as well as posthatch stages (C1, C8, C22, and adult chickens) were included in the study. We also investigated the possible regulatory role of somatostatin (SRIH) in this specific endocrine function of CRH. The perifusion studies show that CRH stimulated the TSH release at all stages tested. The 10 and 100 nM oCRH doses were almost equally effective at the early embryonic stages while in most posthatch stages the higher oCRH dose was significantly more effective than the lower one. The stimulation factor, representative for the relative increase in TSH secretion following oCRH challenge, was high at early embryonic stages and clearly lower in adult animals. This seemed to be related to an age-dependent increase in basal TSH secretion levels. In both embryonic (E19) and posthatch (C8) chicks a pretreatment of the pituitaries with SRIH lowered the sensitivity of the thyrotropes to an oCRH challenge. This effect was more pronounced in the posthatch chicks compared to the embryos. The results show that CRH is capable of stimulating the TSH secretion during the entire life cycle of the chicken and that SRIH may play an important role in the fine-tuning of this response by lowering the sensitivity of the thyrotropes to CRH.

Ca2+ responses to ATP via purinoceptors in the early embryonic chick retina.

1. The action of adenosine triphosphate on cytoplasmic Ca2+ concentration ([Ca2+]i) was studied in the retinal cell of early embryonic chicks with fura-2 fluorescence measurements. The fluorescence was measured from the whole neural retina dissected from chick embryos at embryonic day three (E3). 2. Bath application of ATP (> or = 30 microM; EC50, 128 microM) raised [Ca2+]i by the release of Ca2+ from intracellular Ca2+ stores, since the Ca2+ response to ATP occurred even in a Ca(2+)-free medium. 3. The Ca2+ response to ATP was mediated by P2U purinoceptors. An agonist for P2U purinoceptors, uridine triphosphate (UTP), evoked Ca2+ rises more potently (> or = 3 microM; EC50, 24 microM) than ATP. Agonists for P2X purinoceptors, alpha, beta-methylene ATP and beta, gamma-methylene ATP, or an agonist for P2Y purinoceptors, 2-methylthio ATP (500 microM each), caused no Ca2+ response. Suramin (100 microM) and Reactive Blue 2 (50 microM) almost completely blocked the Ca2+, responses to 500 microM ATP and 200 microM UTP. 4. The developmental profile of the Ca2+ response to ATP was studied from E3 to E13. The Ca2+ response to ATP was largest at E3, drastically declined towards E8 and decreased further until E11-13. 5. These results suggest that the Ca2+ mobilization by ATP via P2U purinoceptors is characteristic of early embryonic retinal cells.

Research Note: Antibody Responses to Sheep Erythrocytes in Early (k+) and Late (K) Feathering Chicks in a Broiler Line

Antibody titers in response to injections of sheep erythrocytes were measured in several different groups of early and late feathering chicks from 8 to 35 days of age. Antibody titers and rate of development of antibody responses were similar in early and late feathering chicks, reaching a plateau by 21 days of age.

New Breeding Localities of the Bridled Tern Sterna anaethetus and its Measurements

The first breeding record in Japan of Bridled Tern Sterna anaethetus is reported from Nakanokami-shima, Okinawa prefecture, South Ryukyus (Abe and Mano 1980). In this paper, we report two other breeding localities of the species. One is Fude Rock where we have already suggested its breeding. The survey of this area was made on 27 and 28 June 1981. Fude Rock is a small rocky islet situated 12km NE of Seto-zaki, Miyako-jima, Okinawa prefecture, having an area of 140m×70m and the altitude, 9m. There is a lighthouse on the islet. Sterna anaethetus, Sterna sumatrana, Anous stolidus and Sula leucogaster settled on Fude Rock and adjacent tiny rocks. About sixty Bridled Terns were breeding, and some of them were in incubation. Another breeding locality is Panari commonly called, Gunkan-jima, is situated near the southeastern end of Miyako-jima. We visited this area on 9 July 1981. The area is a small ring-shaped coral reef, and there are many small rocks at the eastern side of the area. Sterna anaethetus, Sterna sumatrana and Anous stolidus were observed on these rocks. About one hundred or one hundred and fifty Bridled Terns were counted, and their eggs and early chicks were found. The measurements of the Bridled Terns captured on Nakanokami-shima are given.

HATCHABILITY OF EGGS AND PERFORMANCE OF SCWL AND BROILER BREEDER HENS FED SOYBEAN MEAL AND FABABEAN MEAL DIETS

Two experiments were conducted to determine the effects of feeding fababean meal diets to laying hens. Body weight, feed consumption, egg production, egg weight, eggshell strength, and hatchability of eggs were the parameters recorded. In exp. 1, where two types of hens (Single Comb White Leghorn (SCWL) and broiler breeders) were maintained in floor pens, hens fed a diet containing fababean meal had lower final body weights, lower average egg weight, and lower percentage hatchability of eggs than those fed soybean meal. Feed utilization, egg production, and eggshell strength were not significantly affected by diets. In exp. 2, in which SCWL were maintained in cages, hens fed diets containing 29.75% fababean meal required more feed per dozen eggs, had lower egg weights and had lower percentage hatchability than hens fed diets containing 7.20% soybean meal. Body weights, feed per bird per day, egg production, and eggshell strength were not significantly affected by diets. Supplemental dietary lysine improved feed conversion and percent hatchability of eggs for hens fed the fababean diets. The combined number of early dead chicks and infertile eggs was higher for eggs from the hens fed fababean meal diets than those fed soybean meal diets.

A scanning electron microscopic study of the developing epithelial scleral papillae in the eye of the embryonic chick.

Eyes of early embryonic chicks possess 14 scleral papillae, derived from the conjunctival epithelium and present as transient structures between seven and 11 days of incubation. These papillae induce the formation of the 14 scleral ossicles, which develop in the adjacent, neural crest-derived ectomesenchyme. Each papilla undergoes a predictable series of developmental changes, divided by Murray ('43) into six morphological stages (M stages 1-6). We have confirmed his staging, and provide a scanning electron microscopic (SEM) evaluation of papilla development. The earliest stage that can be visualized with the S.E.M. is M stage 2. We describe the initial modifications of the surface of papilla cells, the presence of large microvilli and the asymmetrical morphogenesis and growth of the papillae. Papillae are shed by a mechanism that involves elongation of the cells at the base of the papilla. Such moribund papillae consist of necrotic cells coated with fibers.

Serum triiodothyronine levels in the embryonic and post-hatching chicken, with particular reference to feeding-induced changes

Serum triiodothyronine (T 3) levels were ascertained in late embryonic and early post-hatching chicks by radioimmunoassay, with particular reference to feeding-induced changes. The average T 3 concentration was 11 ng% for 17-day embryos, and increased to 31 and 47 ng% for 2 different hatches at 19 days of incubation. The average serum T 3 level on the day of hatching had risen to approximately 330 ng%, but the levels for 1-day-old chicks were less than one-half the values observed closer to hatching. Two-day-old chicks fed for 24 hr consumed little food, and had serum T 3 levels which were the same as for day-old fasted chicks, but 3 times the value for 2-day-old fasted chicks. At 3 days post-hatching and 48 hr after initiating feeding, food consumption had increased and serum T 3 levels had risen 2.5 times that in day-old chicks. Food consumption and T 3 levels remained high in 4- to 6-day-old chicks, but the T 3 concentration had decreased by 10 days of age to an average value of 225 ng%, which was close to that observed at 33–44 days of age. Goitrogen treatments or changes in iodine intake did not prevent a rise in serum T 3 in response to feeding fasted 2-day-old chicks. Serum T 3 levels for 7-day-old cockerels treated with propylthiouracil (PTU) or methimazole from hatching were approximately 60% of control values, whereas the T 3 levels for older cockerels treated with PTU for 25–36 days were only 10% of control values.

Observations of territorial life in breeding season of a pair of Jungle Crow in City Tokyo (to be continued)

In 1969, a pair of Jungle Crow Corvus macrorhynchos was kept under observation from later incubation period (April 13, five days before hatching) at Akasaka, Tokyo, where I lived in its breeding territory, which was about 45.83 ha, 1000m east to west (200m to west, 750m to east from nest) and 700m north to south (500m to north, 200m to south), thus oval in shape, with the nest situated near the round end. The northern (to the direction of winter roost) and eastern (toward summer roost) territorial boundaries are deliminated by big buildings of TBS television and Parliament respectively.The territory contains apartments, buildings of various sizes, small shops and private houses, with wooded shrine of Sanno on the hill of north-east border, wooded lawn slope of Prime Minister's official residence at eastern hill, and on the central hill, two big gingko trees, one of which having crow's nest, stand high with a patch of trees. Thus, there are some greens on central and surrounding hills, between which two main roads, one with highway, run crossing at Tameike (Fig. 1).Main buildings and other objects frequently used by crows, for resting, guarding, food storing and eating places, are numbered on territory map, with distance lines of 50m mesh (Fig. 3) and circles (Fig. 2).Observations were made on the roof of my home about 40m apart from the nesting gingko tree and I could see all directions of surrounding hills, except some blind area at south western part.Observation time, usually more than 2 hours for each observation, was selected according to its purpose of following the male's movements in its morning food search commenced as soon as he returns from flock roost to his territory before sunrise, female's attendance rate to nest and her daytime activity in relation to her mate or intruding other crows, feeding rates to chicks by male and female, food storing and hiding, roosting places, sexual and family life, as well as vocal communication.In the present paper (part 1; to be continued), observation data from April 13 to 30 are given with some tables and figures.1.The incbation is engaged by female only, but male may visits nest with 20-30 minutes intervals, calls her for confirmation or inviting for food, and if the male doesn't return long time from food search, the female may leave the nest in search of him, in some cases advertising herself by circling flight.2. Although sitting on nest in the foliage, the female is very keen to outside event or for vocal communication of the male and as soon as she perceives, or notices by male's voice, other crows trespass flying over beyond territorial boundary, the female at once takes off from the nest directly flying, with attack calls, to the intruders to chase them up from below. The male is, however, usually less aggressive, or even indifferent, being occupied by his job of food search for the day (But, when he is less occupied he may lead the defense chase of intruders).3. Finished the daytime activity of food search toward evening, the male rests on high top or antenna of building more or less 100m apart from the nest, and the female leaves the nest to pass some 15 minutes with the male preening or billing each other, and together return to nest site (to gingko tree adjacent to nesting gingko). Thus ended their activity of the day, the male leaves (with soft 'ka' of roosting signal vocal) to common flock roost about 1km from the nest site and the female gets back to the nest for her night incubation or brooding of early chicks (from 31st day after hatching the female also flew off to roost).4. Before sunrise, the male comes back to his territory in the dark of twilight, which the female on nest at once notices by his approaching call notes, and answering to him she flies out to adjacent tree to wait his arrival.

Regulation of Lipogenesis and the Total Activities of Lipogenic Enzymes in a Primary Culture of Hepatocytes from Prenatal and Early Postnatal Chicks

Abstract Hepatocytes prepared from the livers of 18- or 19-day-old chick embryos and maintained in culture medium containing serum for 3 days exhibited marked induction of the lipogenic pathway. Incorporation of [U-14C]glucose into fatty acids and the total activities of malic enzyme, fatty acid synthetase, and ATP-citrate lyase increased by 1000-, 47-, 21-, and 4.5-fold, respectively. When l-triiodothyronine was added to the culture medium, the activities increased a total of 2500-, 140-, 40-, and 8-fold, respectively. The increases in the rate of fatty acid synthesis and total activity of malic enzyme were inhibited by bovine serum albumin, human thyroxin-binding prealbumin, and rabbit anti-thyroxin serum. Inhibition was reversed by adding a large amount of l-triiodothyronine. Thus, thyroid hormone was a major serum factor causing induction of the lipogenic pathway. Oxidation of [1-14C]acetate to CO2 and the total activity of NADP-isocitrate dehydrogenase were not affected by incubating the cells with or without l-triiodothyronine. The activity of lactate dehydrogenase decreased during the culture period. This induction of the lipogenesis pathway quantitatively mimics changes in the pathway which occur when newly hatched chicks are fed a high carbohydrate mash diet. Glucagon, cAMP, and free stearate also inhibited the induction of lipogenesis and its associated enzymes. These compounds also inhibit fatty acid synthesis and elevate fatty acyl-CoA levels in freshly prepared hepatocytes. Hence, glucagon and free fatty acids exert both long and short term regulation over fatty acid synthesis, possibly via changes in the intracellular concentration of fatty acyl-CoA.

On the Relationship between Fatty Acid Synthesis and the Total Activities of Acetyl Coenzyme A Carboxylase and Fatty Acid Synthetase in the Liver of Prenatal and Early Postnatal Chicks

Abstract Fructose and lactate markedly stimulated fatty acid synthesis from [1-14C]acetate in isolated cells prepared from the livers of unfed neonatal chicks (21 or 22 days of incubation). In liver cells obtained from unhatched chicks (19 days of incubation) fructose and lactate had very small stimulatory effects on fatty acid synthesis. The increase in fructose- and lactate-stimulated fatty acid synthesis during hatching was about 20-fold. Pulmonary respiration began on the 20th day and the chicks were hatched by the 21st day. Fatty acid synthesis from [1-14C]acetate (plus citrate) or [1,5-14C]-citrate in a cytosol fraction of liver increased about 20-fold during the hatching period. Concomitantly, there were 6.5- and 4-fold increases in the total activities of acetyl-CoA carboxylase and fatty acid synthetase, respectively. The effect of hatching on the total activity of fatty acid synthetase could be mimicked by incubating 18-day-old embryos in an atmosphere of 100% oxygen for 24 hours. The oxygen treatment did not affect the total activity of acetyl-CoA carboxylase or the rate of fatty acid synthesis in isolated hepatocytes (plus or minus fructose). Injecting glucose or fructose into 18-day-old embryos had no effect on the total activity of acetyl-CoA carboxylase or fatty acid synthetase. Feeding the neonatal chicks increased the total activities of both acetyl-CoA carboxylase and fatty acid synthetase. If the neonatal chicks were not fed, the total activity of acetyl-CoA carboxylase did not change for at least 3 days. In contrast, the total activity of fatty acid synthetase continued to increase during those 3 days of fasting. The total activities of both enzymes were increased when unfed neonatal chicks were given a single glucose or fructose injection. The effect was not observed until 6 hours after administration of the sugar despite the fact that the rate of fatty acid synthesis was stimulated by more than 5-fold at 1½ hours after the injection. The results suggest that acetyl-CoA carboxylase and fatty acid synthetase are not part of an operon or its eukaryote equivalent, and that changes in their total activities did not initiate changes in the rate of fatty acid synthesis.

Regulation of Fatty Acid Synthesis in the Liver of Prenatal and Early Postnatal Chicks: HEPATIC CONCENTRATIONS OF INDIVIDUAL FREE FATTY ACIDS AND OTHER METABOLITES

Abstract A normal mash diet or a single glucose injection stimulates fatty acid synthesis and increases the total activities of acetyl coenzyme A carboxylase, fatty acid synthetase, and malic enzyme in the livers of neonatal chicks. Feeding and glucose injection caused a decrease in the concentration of free fatty acids and fatty acyl-CoA and an increase in α-glycerophosphate and free CoA. These concentration changes are appropriate for intermediates which may regulate both the rate of fatty acid synthesis and the concentration of the lipogenic enzymes. The hepatic concentrations of citrate and acetyl-CoA were unaffected by feeding or glucose injection. During the hatching process, total activities of acetyl-CoA carboxylase and fatty acid synthetase in the liver increased but the rate of fatty acid synthesis did not. Concomitantly, free stearate in the liver decreased, but none of the other metabolites indicated above were affected. Fatty acid synthetase increased and hepatic free stearate decreased when embryos were incubated in 100% oxygen. Stearate or a metabolite derived from stearate is a potential negative regulator of the concentration of fatty acid synthetase in chick liver. Injection of glucose into 18-day-old embryos markedly increased the α-glycerophosphate content of the liver but had no effect on the total activities of the lipogenic enzymes. Hence, α-glycerophosphate is not a direct regulator of the total activities of acetyl-CoA carboxylase or fatty acid synthetase in embryonic chicks.

Pace-Setting Mechanisms of the Nesting Cycle in the Ring-Billed Gull

AbstractRecords of the incidence of sitting, provisioning and other attentive activities by parent Ring-billed Gulls at their nests were obtained for successive daily stages of the breeding cycle. The normal progression of stimulus features at 112 nests was experimentally delayed, advanced, arrested, accelerated and reversed by exchanging eggs and chicks of various ages for information on the effect of such manipulations on the progress of the breeding cycle. A series of undisturbed nests provided control data. The incidence of sitting activity at control nests (two parents alternating) was 99+%, when eggs were present, dropped to 90% at hatching and remained at a plateau at that level for 3 days, then declined at about 13% per day. Full time (egg-level) sitting was extended by experimentally postponing the introduction of chicks, shortened by early introductions and restored by returning to eggs after as much as four days with chicks. The 90% level of the early post-hatching period was induced by replacing eggs with chicks regardless of the time of the introduction (up to 8 days early or late) or the age of the introduced chicks (up to 6 days of age). The post-plateau decline was delayed and attenuated by arresting the normal nest progression at early chick stages, and advanced and accelerated by accelerating the progression. Provisioning (feeding the young) activity appeared with the introduction of chicks at any time, early or late in the cycle, and ceased abruptly with a return to eggs. The level of provisioning increased over the first two days to an incidence level of about 7%, then gradually declined after the fifth day. Exchanges of eggs and chicks were generally well tolerated by parent gulls in the delaying, advancing, arresting and accelerating experiments but not where the progression was reversed from advanced chicks to eggs or early chicks. The data suggest: a - The pace-setting mechanisms of the breeding cycle switch from internal (hormonal) to external (embryo and chick development) regulators early in the incubation phase of the cycle. b - Changes in parental activity at hatching are quantitatively uniform and are triggered by non-specific stimuli associated with cliicks. c - Changes in parental activity after the second day are quantitatively regulated by changing stimuli associated with growing chicks.

Studies on Immunologic Depression in Chickens

Summary Embryonic and early posthatching chicks were injected with equivalent amounts of bovine serum albumin and human γ-globulin on the basis of body weight and their subsequent humoral antibody response estimated by quantitative methods. Embryos injected at 11 days of incubation showed, in comparison with saline controls, a slightly lower but statistically nonsignificant antibody response, at 45 days after hatching, and no effect at 100 days. Embryos given a depressive injection on the 16th incubation day showed a statistically significant depression of antibody response at 45 days after hatching, but none at 100 days. Chicks injected at 1 day after hatching showed depression quantitatively similar to that of the 16-day embryos. Chicks at 5 and 9 days of incubation, injected into the yolk sac with large amounts of BSA, showed no effect on their antibody response at 100 days. Intraperitoneal injections into young posthatching chicks were more effective than equal intravenous injections, both as concerns the degree of antibody depression and duration of the depression. Human γ-globulin injected into 16-day embryos, produced a significant depression of the antibody response to bovine serum albumin (cross-depression) at 45 days of age. No cross-depression was discernible at 100 days. Antibody responses of male and female birds, on the basis of mg antibody/ml serum, were not significantly different, nor were body weights of protein-injected birds in comparison with saline controls.

Heritabilities, Sex Differences, and Phenotypic Correlations for Six Feathering Characteristics ,

ABSTRACT PLUMART and Mueller (1954) showed that early feathering chicks were superior to late feathering ones in that they feathered more rapidly and possessed fewer pinfeathers during the first 12 weeks of life. Hurry and Nordskog (1953) obtained heritability estimates of .33 and .42, respectively, for feathering in 8 week New Hampshires and Barred Plymouth Rocks. In both breeds there were both early and late feathering chicks. The present study was designed to obtain estimates of heritabilities, measure sex-differences, and determine phenotypic correlations for 6 feathering traits in early feathering White Plymouth Rocks. METHODS AND MATERIALS Six feathering characteristics were studied. They were: the degree of juvenile feather development in the breast pterylae at 10 days, the amounts of feather development on the back at 10 days, 5 weeks, and 7 weeks, the number of pinfeathers in the sheath stage found in the back area at 10 weeks, and the amount . . .

Some Phenotypic Differences Among Homozygous, Heterozygous, and Hemizygous Late Feathering Chicks ,

INTRODUCTIONTHE desirability of establishing the sex-linked recessive gene for early feathering in all commercial strains of chickens is indicated by the increased protection from chilling and reduced feather picking and cannibalism which result. Of particular interest to broiler producers is the better dressed appearance of birds possessing this gene (Plumart and Mueller, 1954). Warren (1925 Warren (1944) and Mueller et al. (1952) described methods to classify early and late feathering chicks in two distinct groups. A method of phenotypic differentiation between homozygous and heterozygous late feathering genotypes would be desirable as it would eliminate the need of progeny tests. Phenotypic identification of genotype would be possible if the late feathering gene were incompletely dominant to its allele. This study was designed to provide information on the phenotypic expression of the sex-linked late feathering gene in homozygous, heterozygous, and hemizygous chicks.METHODS AND MATERIALSThe stock used consisted of Rhode Island …

Classification of Sex-Linked Early and Late Feathering in 10-Week-Old Chickens

Warren and Gordon (1935) found that the juvenile primaries, axial, and secondary feathers were molted four to six weeks earlier in White Leghorns which were early feathered than in Rhode Island Reds and Light Brahmas which were late feathered. It has not been generally recognized, however, that this difference is consistent enough to classify early and late feathering within a single strain of birds.For the present study, wing and tail feather development between 6 and 12 weeks of age was examined in early feathering and late feathering stocks, which included New Hampshires, White Plymouth Rocks, Black Australorps, and various crossbreds. Definite differences were noted for the pattern of molt in early and late feathering chicks, regardless of breed.Most early feathering chicks could be distinguished at any time, between 6 and 12 weeks of age by the presence of both juvenile plumage (first set) and post-juvenile plumage (second set) .

The distribution of copper64 in early embryo chicks

The distribution of copper⁶⁴ in early embryo chicks