Comparative cytological study of Phasianus colchicus,Meleagris gallopavo,and Gallus domesticus

Summary Since viable intergeneric hybrids between the chicken (Gallus domesticus) and the pheasant (Phasianus colchicus) have been reported, as well as interfamilial hybrids between the chicken and the turkey (Meleagris gallopavo), the chromosome complements of the pheasant and the turkey were compared with that of the chicken. In these three species belonging to the order Galli, the Z-chromosomes appeared to be identical, while the autosomal complements of the pheasant and the turkey differed radically from that of the chicken. It was noted with some surprise that the pheasant of the family Phasianidae and the turkey of the family Meleagridae have very similar chromosome complements, at least so far as gross morphology of somatic metaphase chromosomes is concerned.This work was supported in part by grant C-5138 from the National Cancer Institute, U.S. Public Health Service, and grant C-17601 from the National Science Foundation.The authors gratefully acknowledge the generosity of Rea's Game Birds, Paramount, California, who supplied the pheasant chicks, and the McPherin Hatcheries, Sunnymead, California, who furnished the turkey chicks. The authors also appreciate the editorial assistance of'Patricia A. Ray.     

Intestinal adaptation to diet in the young domestic and wild turkey (Meleagris gallopavo)

The short-term effects of diet on jejunal growth, alanine transport rate, and leucine aminopeptidase activity (LAP) were compared in the domestic and wild turkey poult. One-day-old poults of each strain were fed diets of high vs., low protein, with carbohydrate varied to maintain isocaloric conditions. Prior to feeding, relative jejunal mass and alanine transport rates were not significantly different in the two turkey strains, whereas LAP activity was 270% higher in wild poults. After feeding for 72 h, relative jejunal mass doubled in both turkey strains. In domestic turkeys, alanine transport rate and LAP activity were reduced by approximately 42% and 25%, respectively, in poults fed a 24% protein-69% carbohydrate diet vs. a 49% protein-35% carbohydrate diet. Analysis of the combined data from feeding experiments revealed that alanine transport rate was not correlated with total food, protein or lipid intake, but was negatively correlated with carbohydrate consumption (P<0.05). In wild turkeys, neither alanine transport rate nor LAP activity were altered by diet. These results reveal that domestic turkey hatchlings can modulate protein digestive and absorptive functions as protein/carbohydrate composition of the diet changes and suggest that high dietary carbohydrate down-regulates the intestinal alanine transporter.     

FHF-2 in the turkey (Meleagris gallopavo)

A cDNA clone homologous to the fibroblast growth factor homologous factor (FHF-2) was isolated and sequenced from the turkey (Meleagris gallopavo). The DNA sequence of the turkey was almost identical to that of the chicken (99% similarity) differing at only 8 of 770 nucleotides in the coding region resulting in a single amino acid difference between these poultry species. The 3'UTR of the turkey FHF-2 gene was 445 nucleotides in length and included an imperfect CT microsatellite (ms) repeat. The sequence of the 3'UTR was amplified from genomic DNA of the chicken and found to be highly conserved differing at only three nucleotides when compared to the turkey. Length of the CT repeat was indifferent in a sample of 52 turkeys (monomorphic) however, the number of CT repeats was greater in the turkey than in the chicken. No inter-individual polymorphism was detected in multiple sequences of the 3'UTR of the FHF-2 gene in the turkey. Based on comparison of the turkey and chicken sequences, the mutation rate for coding and associated non-coding (3'UTR) regions of FHF-2 are approximately equal.     

Chemical and biological evidence for presence of estrogens in the domestic turkey (Meleagris gallopavo)

Solvent partitioning, column chromatography on activated alumina, and Ittrich extraction of Kober chromogens were employed to isolate, identify and quantitate estrone, estradiol-17B and estriol from blood of individual turkey hens. The intravaginal tetrazolium method was used to estimate the biological potencies of the three fractions separated chromatographically. The data show that estrone is the main estrogen present in heart blood of laying turkeys, with lesser amounts of estradiol-17B and estriol. Data are presented on the accuracy, precision, sensitivity, and specificity of the methodology used.     

Demonstration of W chromosome-specific repetitive DNA sequences in the domestic fowl,Gallus g. domesticus

Evidence is presented to demonstrate the presence of W chromosome-specific repetitive DNA sequences in the female White Leghorn chicken, Gallus g. domesticus, based on two different experimental approaches. First, ³H-labelled, female chicken DNA was hybridized with excess, unlabelled, mercurated, male DNA, and unhybridized single-stranded ³H-DNA (³H-SHU-DNA) was recovered by SH-Sepharose and hydroxyapatite column chromatography. Approximately 24% of the hybridizable ³H-SHU-DNA was female-specific and localized on the W chromosome. The second approach was to examine female-specific DNA fragments among the digests of chicken DNA with various restriction endonucleases. Among them, we found that digestion with XhoI produced two prominent female-specific bands of 0.60 kb (= kilobase pairs) and 1.1 kb. The 0.60 kb fragment was isolated and ³H-labelled by nick-translation. Female-specificity of the ³H-XhoI—0.60 kb DNA was judged to be at least 95% under the conditions of hybridization with membrane filter-bound DNA. Presence of amplified XhoI—0.60 kb DNA on the W chromosome seems to be limited to different lines of G. g. domesticus and no such repeat was detected in three species belonging to other genera in the order Galliformes and in three species belonging to other avian orders.     

Metabolism and motility of turkey (Meleagris gallopavo) spermatozoa in the presence or absence of oxygen, glucose and fructose

Sugar consumption by turkey spermatozoa for 1 hr at 37 degrees C was similar in the presence or absence of oxygen, and with glucose or fructose in the medium. Motility of the spermatozoa at the end of the above incubation period was lower under anaerobic than aerobic conditions. Fructose enhanced the oxygen uptake of spermatozoa in comparison with that in the glucose-containing medium. Omission of sugar from the medium depressed respiration but not motility of the spermatozoa. The rate of oxygen uptake by the spermatozoa during a 3-hr incubation period was higher in a 3.3-mM than a 15.0-mM glucose medium. Fructose was formed from glucose under aerobic but not under anaerobic conditions. Fructose originating from glucose was used for fructolysis, when the glucose reserve in the medium was almost exhausted.     

Lung growth of the turkey, Meleagris gallopavo: I. Morphologic and morphometric description

To describe lung growth qualitatively and quantitatively from prehatch to adulthood of an unselected line of turkey, a precocial avian species, 36 male turkeys, three in each age group, were killed at 22 and 25 days of incubation, on hatch day, and at 1, 4, 7, 10, 14, 21, 28, 112, and 420 days of age. Body weight and lung volume were measured. A three-level cascade sampling system was used to prepare lung tissue for morphologic and morphometric observation by light microscopy. Point and intersection counting were used to estimate volume and surface densities of lung compartments relative to lung volume. Absolute volumes and surfaces of lung compartments were calculated. Bilogarithmic regressions provided allometric equations to describe growth of the lung in three phases: Tissue proliferation--explosive growth of lung volume relative to body weight and of the gas-exchange compartment within the lung. At 22 days of incubation there were few air and blood capillaries and a great deal of tissue that looked like mesenchyme between the parabronchi. Within the 6 days prior to hatch, the surface area of air capillaries increased 11-fold and of blood capillaries 27-fold, whereas the volume of interparabronchial tissue decreased 58%. Equilibrated growth--from hatch day to 28 days of age, most lung compartments grew evenly with lung volume. Regulated growth--from 28 days of age to adult, all lung compartments, except large vessels and exchange compartment, grew more slowly than the entire lung. Interatrial septa lengthened and their epithelial covering thinned, infundibula became more apparent, and interparabronchial connective tissue reached a minimal volume density in the adult lung.     

The mitochondrial genome sequence and molecular phylogeny of the turkey, Meleagris gallopavo

The mitochondrial genome (mtGenome) has been little studied in the turkey ( Meleagris gallopavo ), a species for which there is no publicly available mtGenome sequence. Here, we used PCR-based methods with 19 pairs of primers designed from the chicken and other species to develop a complete turkey mtGenome sequence. The entire sequence (16 717 bp) of the turkey mtGenome was obtained, and it exhibited 85% similarity to the chicken mtGenome sequence. Thirteen genes and 24 RNAs (22 tRNAs and 2 rRNAs) were annotated. An mtGenome-based phylogenetic analysis indicated that the turkey is most closely related to the chicken, Gallus gallus , and quail, Corturnix japonica . Given the importance of the mtGenome, the present work adds to the growing genomic resources needed to define the genetic mechanisms that underlie some economically significant traits in the turkey.     

Ovarian steroidogenesis during follicular maturation in the domestic fowl (Gallus domesticus)

The steroidogenic potential of various physiological compartments within the ovary of the hen were examined using in vitro systems. Three-hour incubations of individual whole small follicles (less than 1 mm-1 cm) or 100,000 collagenase-dispersed theca cells of the five largest ovarian follicles (F1-F5) were conducted in 1 ml of Medium 199 at 37 degrees C in the presence and absence of luteinizing hormone (LH) (0.39, 0.78, 1.56, 3.13 and 6.25 ng), progesterone (5 ng), and dehydroepiandrosterone (DHEA, 5 ng). Steroid output was measured by radioimmunoassay of incubation media. Progesterone was not produced by small follicles although they are a major source of DHEA and estradiol and a significant source of androstenedione. Output of DHEA, androstenedione and estradiol was highly stimulated by LH. The substrate for androstenedione and estradiol in small follicles is probably DHEA. Output of DHEA and androstenedione in theca cells of F2-F5 was stimulated by LH in a dose-related manner. A dose-response relationship between estradiol output and the concentration of LH in media was not apparent in theca cells from F2-F5. Steroidogenesis in theca tissue of large follicles occurs predominantly via the delta 4 pathway. The ability of these theca cells to metabolize progesterone to androstenedione is lost between 36 and 12 h before ovulation. Their ability to metabolize DHEA to androstenedione is still present 12 h before ovulation. Aromatase activity is significantly reduced between 36 and 12 h before ovulation. These data indicate that both large and small follicles can be stimulated by LH. The small follicles are the major source of estrogen. As the large yolky follicles mature, steroidogenesis shifts from the delta 5 to the delta 4 pathway. By 12 h before ovulation, the F1 follicle has lost the ability to convert progesterone to androstenedione. The inability of the largest ovarian follicle to convert progesterone to androstenedione contributes at least in part to the preovulatory increase in the plasma concentration of progesterone that generates the preovulatory LH surge by positive feedback.     

Comparative embryonic development of the skeleton of the domestic turkey (Meleagris gallopavo) and other galliform birds

Ossification sequences are poorly known for birds in general, even for common domestic and experimental species. Such sequences constitute a rich source of data on character evolution, and may even provide phylogenetic information. It is not clear, however, what factors influence ossification sequences and what the relative importance of phylogeny is to the sequences. Galliformes constitute a good group to examine these variables. These birds are osteologically conservative, have precocial young, but have a broad spectrum of body sizes and incubation periods. Here, I describe the embryonic ossification of the skeleton in the domestic turkey (Meleagris gallopavo), and compare it to the domestic chicken (Gallus gallus) and the Japanese quail (Coturnix coturnix). Ossification sequences in this group are not affected by egg size or incubation period. They also appear to be independent of both the spatial location and the embryonic tissue from which the osteogenic cells originated. Accumulation of a wider sample of ossification sequences from more morphologically variable avian taxa will be necessary in order to test functional and phylogenetic effects.     

The passage of spermatozoa through the vitelline membrane in the domestic fowl,Gallus gallus

Summary The developing outer layer of the vitelline membrane of the ovum in the posterior part of the infundibulum of the domestic fowl contains many spermatozoa in nearly parallel orientation with its inner layer. When the acrosomal region of a spermatozoon approaches or contacts the inner layer, promptly undergoes the acrosome reaction. The outer acrosomal membrane and overlying plasma membrane fuse together and the apical region of the acrosome opens, so that the acrosomal contents are released. Meanwhile the spermatozoon remains a time in contact with the surface of the inner layer, and the network of the inner layer just under the tip of the sperm head begins to be dissolved. This dissolution extends downward forming a tunnel, approximately 9 m in diameter. The spermatozoon then passes through the inner layer obliquely via the central region of the tunnel and arrives at the perivitelline space.The authors are greatly indebted to assoc. prof. Dr. Osamu Koga for his valuable advices. The authors also wish to thank Mr. Takayuki Mori for his helpful suggestions and technical advices. This investigation was supported by a grant from the Ministry of Education of Japan (156185)     

Effects of temperature on the immobilization and the initiation of motility of spermatozoa in the male reproductive tract of the domestic fowl, Gallus domesticus

1. The motility of undiluted fowl spermatozoa taken from testis, epididymis and ductus deferens was negligible at 40 degrees C, around the normal avian body temperature. 2. The immobilization was not permanent and motility was restored by decreasing the temperature to 30 degrees C or by suspending in a NaCl/TES buffer with 2 mM Ca2+, 2 mM HCO3- or 10% seminal plasma at 40 degrees C. 3. Demembranated spermatozoa taken from testis, epididymis and ductus deferens were also immotile at 40 degrees C. However, these spermatozoa were restored the motility at 30 degrees C except testicular spermatozoa. 4. These results suggest that the capacity of movement of fowl spermatozoa can be readily obtained from testis, but that these spermatozoa are immotile due to temperature-dependent immobilization in the male reproductive tract. 5. Furthermore, it is possible that changes in environmental temperature at ejaculation are one of the important exogenous physiological factors of the initiation of fowl sperm motility.     

Fertilizing competency of multiple ovulated eggs in the domestic fowl (Gallus domesticus)

Fertilizing competency of multiple ovulated eggs in the domestic fowl was examined by fertilization in vitro and early development in culture. Normal laying hens (White Leghorn) were treated with 75 IU of PMSG for 7 days followed by injection of anterior pituitary extracts from chickens (CAPE). Ovulation began to occur 7.5 h after injection of CAPE. These hens ovulated 1-7 ova but some premature ovulation of GV stage ova were observed. In vitro fertilization of the multiple ovulated ova was examined by inseminating 10(6)-10(7) sperm onto the germinal disks in m-Ringer's solution. The gamete or zygote nuclei were detected by DNA specific fluorescence using DAPI (4',6'-diamidino-2-phenylindole) in the histological section prepared from the germinal disk. Process of fertilization was examined in the eggs incubated for 4 h after insemination in DMEM + liquid albumen at 41 degrees C under the atmosphere of 5% CO2 in air. Fertilization rate of the total multiple ovulated eggs was 55% (11/20), in which 90% (9/10) and 10% (1/10) in the eggs recovered 7.5-8.5 h and 9.0-9.5 h after CAPE injection were obtained, respectively. Normal pronuclei were formed in five eggs of those recovered 7.5-8.5 h after CAPE injection. Early development after fertilization in vitro was also examined by incubation for 12 h in DMEM + liquid albumen at 41 degrees C under the atmosphere of 5% CO2 in air. Although development in vitro was delayed compared to that in utero condition, normal development was observed in naturally and multiple ovulated eggs.(ABSTRACT TRUNCATED AT 250 WORDS)