Yolk Sac Retraction Research Articles

Morphological and Skeletal Abnormalities Induced by Rolapitant: An Antiemetic Agent

IntroductionRolapitant hydrochloride is a highly selective, long-acting antagonist of the neurokinin-1 (NK1RA) receptor with a high level of central nervous system (CNS) penetrance. Clinically, it is given to cancer patients with high and moderate emetogenic chemotherapy to prevent chemotherapy-induced nausea and vomiting (CINV). The facts produced in this research support the interpretation of teratogenic effects like anatomical malformations and abnormal skeletal changes affected by high doses of rolapitant in developed chick embryos, which can be extrapolated to humans due to gaps in the literature regarding the teratogenic potential of rolapitant. As rolapitant is metabolized by the liver and excreted through the kidney by leaving a deep impact on the various systems of the body and due to its high plasma concentration with a half-life of more than 180 hours, the study was conducted to acquire some additional information about its adverse effects over the various body systems. Chick is one of the best animals for embryological laboratory research. For various reasons, it is preferred to research embryology in chicks or domestic hens (Gallus domesticus). Chick eggs are large, readily available all year, easy to incubate, and regulate artificially.AimThis study aimed to determine the morphological and skeletal abnormalities due to the effect of rolapitant, an antiemetic agent, in developing White Leghorn (G. domesticus) chicken eggs.Materials and methodsThe experiment used 300 fertilized White Leghorn chicken eggs. The eggs were categorized into five experimental groups (A, B, C, D, and E, each with 30 eggs) and five control groups (a, b, c, d, and e, each with 30 eggs). Rolapitant was administered into the five experimental groups of eggs on incubation day five at various concentrations of 0.00039, 0.0005, 0.00075, 0.001, and 0.00125 mg, respectively, while the control groups received the same volume (0.039, 0.05, 0.075, 0.1, and 0.125 ml, respectively) of normal saline.ResultsAt all doses, the mean weight and crown-rump (CR) length of chick embryos were significantly greater in the control group than in the experimental group. The experimental group died at a higher rate than the control group. Additionally, it was found that the mortality due to the rolapitant dosages increases with dose. All groups except group A showed skeletal anomalies such as poor ossification, bent, and displacement, and morphological abnormalities such as yolk sac retraction, hematoma, and scanty feathers were found in experimental groups C, D, and E. This was shown to be more prevalent in the experimental groups and was exacerbated by subsequent rolapitant dosages.ConclusionRolapitant is toxic when taken in large doses and for an extended period. As a result, rolapitant should be taken only when a valid diagnosis has been established and only at the recommended dose, not at a larger dose or for an extended period of time.

Uso de butirato de sódio em rações pós-eclosão para pintos de corte

ABSTRACT This study was designed to determine adequate levels for sodium butyrate inclusion in pre-hatching and pre-starter feed in order to minimize the negative effects of post-hatch delayed placement on broiler chicks. Newly-hatched chicks were allotted in a completely randomized design, with five treatments, each comprising five replicates of ten birds each. Five dietetic levels of sodium butyrate (control, 0.050, 0.075, 0.100 and 0.200%) were used in the pre-starter feed offered to the chicks in the transporting box and during the pre-starter phase. Performance, yolk sac retraction, plasma glucose concentration, weight and histomorphometry of the small intestine were evaluated after 24 hours of feed access and at 7 days of age. A metabolic trial was performed when the chicks were seven to ten days of age. Supplementation of 0.1% sodium butyrate increased the development of broiler chicks’ intestinal villi at seven days of age but was not able to improve performance in the pre-starter phase. Supplementation with sodium butyrate in a diet offered in the transportation box does not improve broiler performance in the pre-starter phase. Supplementation of up to 0.16% is recommended, in order to improve the metabolizability of the ether extract for broilers at seven days of age.

Clutch formation and nest activities by the setting hen synchronize chick emergence with intestinal development to foster viability

The fertile hen collects eggs in a nest to form her clutch. The egg’s asymmetrical ellipsoid shape encourages placement blunt end up. Chalaza formation centralizes ovum in the egg while its high lipid favors upward positioning as early rotations interface germ with outer thin and access its glucose. Repetitive heating during successive ovipositions together with glucose recovery sustain blastodisc viability. Further turning of eggs upon formal incubation distributes the chorio-allantois over the blunt end while consolidating albumen in its sac at the sharp end. Rupture of the sero-amnionic connection mixes albumen with amnion which the embryo consumes over the next several days. During consumption certain of the proteins directly enter the vascular system while most pass through the jejunum to enter the yolk sac and foster embryonic nutrition. Mineralization of the skeleton, pipping muscle enlargement, multiple fortifications of glycogen, and deposition of subcutaneous fat subsequently occur as liver cholesterol becomes exaggerated. Minimal oxygen during transition from chorio-allantois to pulmonary respiration necessitates umbilical closure together with the heart’s intra-auricle septum as inner to outer shell pipping proceeds. Abdominal pressures during yolk sac retraction force a portion of yolk contents back into the jejunum while bile and pancreatic enzymes initiate its digestion to enhance early mucosal maturation. Concurrently, glycogen is sourced for energy in support of emergence. A narrow hatch window exists for the clutch because of egg uniformity while intermittent pre-incubation heating enabled similar germ development. Hen confinement of emergents to the nest provides insulation and heat sharing to extend body reserves through completion of hatch. Confinement also exposes hatchlings to a mature microbial population from hen excreta that colonize the gastrointestinal tract (GIT). Microbe composition in concert with the hen’s environment advantages digestion of hatchling feedstuffs outside the nest while concurrent mucosal failures generate permanent immunoglobins to commensals as passive ones dissipate. Inherent delays to feed with commercial chicks and absence of a favorable microflora impair early intestinal maturation prior to initial feed access. A pre-starting feed providing high protein that assures amino acids favoring mucin is thought to resist lumen microbes while aiding recovery of delayed development. Concurrent dietary enzyme supplementation and a source of nucleic acids are believed to partially substitute for digestive and nutritional complementation expected from commensals.

Hatching the cleidoic egg: the role of thyroid hormones.

A major life stage transition in birds and other oviparous sauropsids is the hatching of the cleidoic egg. Not unlike amphibian metamorphosis, hatching in these species can be regarded as a transition from a relatively well-protected “aqueous” environment to a more hazardous and terrestrial life outside the egg, a transition in which thyroid hormones (THs) (often in concert with glucocorticoids) play an important role. In precocial birds such as the chicken, the perihatch period is characterized by peak values of THs. THs are implicated in the control of muscle development, lung maturation and the switch from chorioallantoic to pulmonary respiration, yolk sac retraction, gut development and induction of hepatic genes to accommodate the change in dietary energy source, initiation of thermoregulation, and the final stages of brain maturation as well as early post-hatch imprinting behavior. There is evidence that, at least for some of these processes, THs may have similar roles in non-avian sauropsids. In altricial birds such as passerines on the other hand, THs do not rise significantly until well after hatching and peak values coincide with the development of endothermy. It is not known how hatching-associated processes are regulated by hormones in these animals or how this developmental mode evolved from TH-dependent precocial hatching.

The Effect of Dietary Selenium Source on Embryonic Development in Turkeys

The objective of this study was to determine the effect of dietary selenium source on the growth and development of turkey embryos, and egg hatchability. White broad-breasted BUT Big 6 turkeys (1800 females and 150 males) were placed under optimum management conditions. Turkey diets were supplemented with organic selenium, and in the other with inorganic selenium, in the amount of 0.3 ppm. Eggs intended for incubation and examination were collected in week 2, 10, 18 and 23 of the laying season. The average egg weight was higher (p < or = 0.05) in laying hens fed a diet with organic selenium than in layers receiving inorganic selenium. The rate of yolk sac retraction was faster in embryos from the group fed a diet with inorganic selenium, and it reached 0.59 of the complete yolk sac on day 25 of incubation (p < or = 0.05). Selenium source had no effect on the hatching rates of fertilized eggs, which reached 79.61% and 79.84% in laying hens fed organic and inorganic selenium, respectively. In the flocks fed diets supplemented with organic selenium, dead embryos were more frequently characterized by problems with protein utilization (19.28%) and delayed pipping (10.83%). Embryo death rates at the first mortality peak were higher in layers fed inorganic selenium than in those receiving organic selenium (15% vs. 13.5%). The second embryo mortality peak occurred earlier (day 26) in laying hens fed inorganic selenium than in those fed organic selenium (day 28).

Evaluation of a quail embryo model for the detection of botulinum toxin type A activity

Day 15 quail embryos were evaluated as a bioassay to detect biologically active botulinum toxin serotype A (BoNT/A). Embryos injected with ≥20 ng BoNT had >74% determined nonviable; embryos injected with 10 to 0.5 ng BoNT were 70 to 45% nonviable; embryos injected with 1.0 to 0.1 ng BoNT were 59 to 18% nonviable. The LD50 for quail embryos was approximately 0.2 ng BoNT/embryo (28 μg BoNT/kg of body weight). Injection with BoNT did not interfere with yolk sac retraction into the abdominal cavity, but did restrict aircell and eggshell pipping, initiating morbidity and nonviable status and enabling preemptive euthanasia.

Effect of Blocking T4-Monodeiodination on Hatching in Chickens

Chick embryos were injected with iopanoic acid (IOP) on either day 17 or 18 of incubation, and radioimmunoassays of triiodothyronine (T3) and thyroxine (T4) in serum and thyroid glands were performed from day 19 on through pipping and hatching and 1 day after hatching. The IOP was able to block T4 to T3 conversion in chick embryos from day 19 of incubation. Blocking T4 conversion did not delay hatching significantly, nor did it affect embryonic mortality significantly. Yolk sac retraction was not affected at hatching. A rise in serum reverse T3 (rT3 ) and T4 was observed after IOP administration. The rise in T4 could not be explained solely by a decreased T4 conversion. The results indicated that peripheral monodeiodination occurs in the late chick embryo.

Thyroxine and duodenal development in chicken embryos.

To test whether thyroxine (T4) can stimulate duodenal development in chickens, it was administered to 16.5-day-old embryos (strain Hyline 934F of Gallus gallus) (approximately stage 42). Treatment time was closer to the prehatching phosphatase increase, and the single dosage (5 μg) larger than before. Control groups received the following: (1) D-T4 for possible physicochemical variables, (2) windowed shells and saline vehicle, (3) windowed shells or (4) no treatment. Subsequent accumulation of duodenal alkaline phosphatase activity (EC 3.1.3.1) and protein content were monitored as developmental parameters (n = 8–43). Yolk sac retraction, distribution of developmental stages, and mortality were used as indices of maturation and survival. L-Thyroxine treatment increased duodenal alkaline phosphatase significantly (p &lt; 0.01) within 48 h, 24 h sooner than normal. This precocious increase was transient in embryos treated at stage 41. Duodenal protein content was elevated significantly in stage 43 embryos treated with L-T4, but it was not different from control values at later stages. Pooling of time data did not greatly alter duodenal parameters. Yolk sac retraction and shell pipping began sooner in embryos treated with L-T4 than control embryos, however, distribution of developmental stages was unaltered. Increased mortality was found 72 h after L-T4 treatment. After D-T4 treatment no parameter was significantly different. The parameters responding after treatment may be stimulated by thyroxine during development.

Photographic Study of Chick Embryo Development In vitro

A photographic study of development of chick embryos cultured in vitro was conducted in order to demonstrate the relationship between embryos and extraembryonic membranes during culture. Survival of embryos in this system has been extended to 21 days of total incubation (3 days in shell plus 18 days in vitro) and development to Hamburger-Hamilton stage 45 (partial or complete yolk sac retraction). A few mature cultured embryos have “pipped” through the chorioallantoic membrane and have emitted audible peeping.Three-day embryos and egg contents were cultured in commercial plastic wrap suspended in plastic tripods. The yolk sac expanded and flattened to cover the bottom of the culture chamber by five days of total incubation. Downgrowth of the yolk sac vascular system along the plastic wrap walls of the chamber began by six days, while downgrowth of the chorioallantoic membrane (CAM) began by eight days. The CAM often completely enclosed cultured egg contents by 17 days, an event which occurs in ovo by 11 to 12 days. Lack of formation of the albumen sac resulted in inhibition of albumen uptake during the latter portion of incubation.A small number of embryos were on their right side rather than on the normal left side during the first two days of culture. Many of the right side cultured embryos experienced “compensatory torsion” onto their left side by three days of culture (six days of total incubation).

Differential effects of hormones on precocious yolk sac retraction in chick embryos following administration by a new technique

Abstract A simple new technique allowing continuous application of hormones to the chorioallantoic membrane of the embryonated chicken egg is described. By use of this technique, by grafting the pars distalis, and by monitoring the hormonal response, with inhibitors and with induction of glucocorticoid-dependent liver enzymes, yolk sac retraction has been shown to be linked with thyroidal and not with adrenocortical or several other hormones. Evidence is also presented that the pars distalis, from chickens up to at least 18 months old, is capable of autonomous performance of certain adrenocorticotrophic or thyrotrophic functions when grafted on the chorioallantoic membrane of embryonated eggs.

Growth of the Chick Embryo In Vitro

An improved technique is described for in vitro culture of the chick embryo from three days through 21 days of total incubation (three days in shell plus 18 days in culture). Mean survival time for cultured embryos is 18 days of total incubation, and mean morphological stage is Hamburger-Hamilton stage 41 (15 days). Mean measurements of wet weight, dry weight, and right third toe length for stage 45 (partial or complete abdominal yolk sac retraction, 19–20 days) cultured embryos are comparable with corresponding means for stage 42–43 (16–17 days) embryos from control intact eggs. Possible causes of growth retardation in vitro are briefly discussed.

Effects of metopirone on duodenal differentiation and yolk sac retraction in chick embryos.

Effects of metopirone on duodenal differentiation and yolk sac retraction in chick embryos.

The hormonal activities associated with the cephalic and caudal regions of the cockerel pars distalis

The regional distribution of tropic hormone activities in the avian pars distalis was studied by transplanting the cephalic, middle, and caudal regions of the pars distalis of day-old cockerels onto the chorioallantoic membrane of 10-day-old partially decapitated (“hypophysectomized”) embryos. Bioassay was based on body growth (assessed by body weights and third toe lengths) and the growth and histological maturation of the adrenal and thyroid glands and the gonads. The experimental design consisted of normal embryos, hypophysectomized embryos, hypophysectomized embryos with one cephalic region graft, hypophysectomized embryos with one middle region graft, and hypophysectomized embryos with one caudal region graft. All embryos were examined at the end of 20 days of incubation. Hypophysectomy severely retarded growth, vitelline, and chorioallantoic vascular shutdown, yolk sac retraction, feather, and skin development and normal maturation of endocrine target organs. All regions of the pars distalis may contain a grwothsustaining activity (STH? and/or prolactin?) capable of normalizing the length of the third toe in hypophysectomized embryos. The cells of each region apparently retained a normal histological appearance in the grafts. Probable ACTH, TSH, and FSH activities were exclusively associated with the cephalic region of the pars distalis whereas a presumed LH activity originated from the caudal region of the gland. A STH activity may occur throughout the gland but there was no indication of the presence or distribution of MSH or prolactin activities. The data indicate that the secretory repertoire of the pars distalis cells did not apparently change over a 10-day period; in the absence of the hypothalamus or even when the regions were isolated. This indicates that perhaps the hypothalamus in day-old cockerels is not important for the maintenance of the secretory integrity or regional differentiation of pars distalis cells. Apparently the cells of one region do not stimulate or inhibit the secretory differentiation of the other region.

Pulmonary ventilation in a population of hatching chick embryos.

Synopsis Two experiments were made to study pulmonary ventilation in the hatching chick embryo with particular reference to the part played by the air cell. The hatchability of embryos without access to the air cell was the same as for normally positioned embryos. The lungs of about 35 per cent of the normally hatching embryos were inflated in the air cell, but 65 per cent were inflated after breathing atmospheric air. The shell was cracked but not pipped before the outer membrane was penetrated. Comparisons between different groups of normally and abnormally positioned unhatched embryos revealed that the air cell had an insignificant respiratory value, but that the mechanical advantages of the large end seemed apparent. The time relationships between lung inflation, inner membrane perforation, pipping, yolk sac retraction, outer membrane perforation, lung discoloration and hatchability were studied. Equations were derived for the regression on time of each of the seven variables studied. Statistically insignificant differences in hatchability were observed between the 2 groups of embryos which hatched from the large or small end of the egg. It is suggested that lung inflation occurs when a certain threshold in the respiratory movements of thoracic muscles is reached. The threshold is attained by the rising anoxia, and probably other stimuli. The chick embryo's lungs, which lack elastic recoil, respond to the threshold and start utilising air. It is doubtful whether the embryo needs the very high partial pressure of carbon dioxide in the air cell. It is feasible to believe that CO2 is an inevitable metabolic by‐product, and that it is stored in the air cell. The air cell also serves as a resting place for the chick while retracting the yolk sac. Through evolution, however, the chick embryo may have built up a high physiological tolerance to the CO2 which it encounters upon entering the air cell.