Molecular heterosis at the conalbumin locus in the ring-necked pheasant (Phasianus colchicus)

Summary Egg whites of Phasianus colchicus containing conalbumin of the heterozygous type show a stronger inhibitory effect on the growth of Saccharomyces cerevisiae than egg whites with conalbumin of the common homozygous type. This fact is interpreted as an example of heterosis at the molecular level.     

Enzymatic esterification of alkane-2,3-diols by the microsomes of the uropygial glands of ring-necked pheasants (Phasianus colchicus)

Extracts of uropygial glands of ring-necked pheasants (Phasianus colchicus) catalyzed diester formation from tritiated C₁₈ alkane-2,3-diol. Monoacylated diol was also tentatively identified in the enzymatic product. Subcellular fractionation showed that the esterifying activity was located mainly in the microsomal fraction. ATP and CoA were required for the esterification process, and this reaction was stimulated by Mg²⁺. Source of the acyl moieties for esterification was endogenous, and addition of exogenous fatty acid inhibited the reaction. When microsomes were treated with bovine serum albumin (BSA) in order to remove the endogenous source of acyl moieties, palmitoyl-CoA substituted for the ATP and CoA requirement. The pH optimum with ATP and CoA was between 6.0–9.0, while maximal rates of esterification were obtained with palmitoyl-CoA from pH 7.0 to 9.0. Borate ions stimulated esterification. The half maximal velocity was obtained with 2.0 × 10^?4, m diol, and 7.2 × 10^?5, m palmitoyl-CoA. Thiol reagents severely inhibited the esterification reaction with ATP and CoA, while much less inhibition was observed when palmitoyl-CoA was used. It is concluded that a microsomal acyl-CoA-diol transacylase catalyzes stepwise acylation of alkane-2,3-diols to give the diol diester which constitute the major component of the uropygial lipids of ring-necked pheasants.     

Responses of ring-necked pheasant chicks (Phasianus colchicus) to conspecific calls

The locomotor responses of pheasant chicks to conspecific calls and the vocalizations of the chicks relating to their locomotor responses were measured in a test apparatus permitting approach or retreat movements. The brood-gathering call and the content call elicited strong approach from chicks. The alarm call and the squeak call inhibited locomotion in chicks. The hiss call, brood-caution call, fright call and flock call do not greatly affect the locomotion of subjects. The flock call appears to be primarily a care-soliciting call. Conspecific calls appear to be important to the survival of young pheasant chicks in the wild.     

Survival of released pheasants, Phasianus colchicus, in Ireland

The survival of 250 hand-reared pheasants was assessed by resightings of tagged individuals following their release into an open-roofed pen on an estate in Ireland. The death rates per 10 days after release were approximated as 5.5% during the first 30 days, 11.6% between 31–70 days, 6.0% between 70–240 days and 2.3% between 241–365 days. The birds suffered their highest rate of loss (48.2%) during their first 10 days after leaving the release pen. This emergence-related mortality was the major factor influencing changes in the observed death rate following release. Predators, mainly foxes, were initially attracted to the area by the presence of inaccessible prey. Males suffered a higher rate of loss following their emergence from the release pen than did the females, possibly associated with the greater proportion of time thereafter spent outside the pen and hence at risk. The factors affecting the survival of hand-reared pheasants are discussed. It is suggested that reducing densities of birds within pens may increase subsequent survival without resorting to predator control.     

Laying characteristics of one- and two-year old pheasants (Phasianus colchicus, L.)

The aim ofthe study was to assess laying traits, the weight of eggs and characters ofthe laying rhythm of pheasants in the first and second years of reproduction. Pheasants (10 cockerels and 50 hens) were kept in aviaries. Daily, individual control of laying was performed beginning with the day of the first laying and ending with the last egg. The following parameters were evaluated: age at first laying, length of the laying period, number of laid eggs and the average weight of the egg in the 8th week of laying. The laying rhythm was also assessed and comprised: the number of egg clutches, the number of eggs in a clutch, the number of eggs in the longest clutch, the number of intervals, the length of intervals and the longest interval between clutches. During the first period of reproduction, in comparison with the second, pheasants laid slightly more eggs of similar average weight. The first laying period was longer than the second and was characterised by a greater number of egg clutches and greater number of intervals between clutches. The greatest number of eggs was laid in 10-egg and longer clutches, although the l-egg clutches were the most numerous. A positive correlation was found between the number of eggs and the number of clutches, the greatest number of eggs in a clutch and the number of intervals between clutches. The similar values of the reproductive characters of one- and two-year old pheasants point to the possibility of longer utilization of these birds than only for one laying period. On the other hand, the considerable variability between the experimental hens with regard to the number and the length of egg clutches, as well as the intervals between them, indicate the possibility to carry out selection taking into account traits characterising the laying rhythm.     

Experimental manipulation of yolk testosterone affects digit length ratios in the ring-necked pheasant (Phasianus colchicus)

In humans, most of the mammals and one bird species studied so far, the relative length of individual digits is sexually dimorphic. Most studies of humans have been concerned with the ratio between second (2D) and fourth digits (4D), whereas some studies of humans and other mammals have also investigated other digit ratios. Inter- and intra-sexual variation in 2D:4D may depend on differential exposure to androgens during embryonic life, and the genetic mechanisms linking 2D:4D to androgens may be mediated by Hox genes. Because Hox genes are conserved in vertebrates, similar patterns of variation in digit ratios might be expected across vertebrate classes. The observation of correlations between digit ratios and physiological, psychological and performance traits in humans has generated interest in exploring the possibility that digit ratios are a marker of embryonic exposure to androgens, which have diverse consequences on several phenotypic traits. However, the hypothesis that digit ratios depend on androgen effects during development has never been tested experimentally. In this study, we increased testosterone concentration in ring-necked pheasant eggs and measured length ratios between the second, third and fourth digits of both feet in fully grown offspring. Females from testosterone-injected eggs had larger 2D:3D in the left foot, whereas this was not the case in males. The other digit ratios were unaffected by hormone treatment in both sexes. However, digit ratios showed no sexual dimorphism among controls. Thus, present results are consistent with the hypothesis that variation in testosterone levels during development affects digit ratios.     

Consequences of prenatal androgen exposure for the reproductive performance of female pheasants (Phasianus colchicus)

Maternal hormones in vertebrate eggs can mediate important forms of maternal effects. However, the function of hormone transfer to the eggs is still debated, especially because long-term fitness consequences have been little studied. We investigated the effect of prenatal exposure to physiologically elevated yolk testosterone (T) levels on reproduction of female pheasants (Phasianus colchicus) in captivity. We found that females hatching from T-injected eggs (T-females) had a lower egg-laying rate than controls, and their eggs were more frequently infertile than those laid by control females. There were no effects of prenatal maternal treatment on egg size and yolk T concentration, but eggs carrying a female embryo laid by T-females had smaller yolks than eggs with a male embryo, while there was no sex difference in yolk size among the eggs laid by control females. Progeny sex ratio was unaffected by maternal treatment. These findings suggest that the transfer of high androgen levels to the eggs by the mother is constrained by complex trade-offs between direct effects on her daughters' reproduction and by trans-generational differential consequences on male and female descendants.     

Mercury accumulation in the muscles and feathers of pheasants, Phasianus colchicus (L. 1758)

Mercury concentrations were determined in muscles and feathers of 58 cock pheasants. Birds were collected from seven different polluted sites in southern Poland in 1987. The mercury concentrations in the muscle ranged from 0.010 to 0.026 mug g dry mass. The significantly highest values were found in muscle samples from Przylasek and Przemysl. The levels found in the flight feathers were higher than in breast feathers. Average concentrations in flight feathers ranged from 0.050 mug g (Przemysl) to 0.240 mug g dry mass (Przylasek). © Rapid Science 1998     

Identification of the major histocompatibility complex in the ring-necked pheasant, Phasianus colchicus

Reciprocal immunization between parents of an Illinois family of ring-necked pheasants, Phasianus colchicus, resulted in antisera detecting two pairs of alloantigens segregating among 13 progeny. The four alloantigens were tentatively designated as 1 and 2, transmitted antithetically by the sire, and 3 and 4, transmitted antithetically by the dam. Genetic segregation occurring in second-generation progeny demonstrated that these two pairs of antigens belonged to a single genetic system. This alloantigen system was shown to correspond serologically to the major histocompatibility complex (MHC) of the chicken by cross-reactivity of the antigens of this system with specific subregional chicken MHC reagents, appropriately absorbed with erythrocytes of individual pheasants. These four haplotypes of the pheasant MHC were subsequently designated as MhcPhco-B1, MhcPhco-B2, MhcPhco-B3 and MhcPhco-B4. Traditional immunogenetic analysis of 30 pheasant families produced in this study disclosed a minimum of 14 pheasant haplotypes of this alloantigen system (MHC) to be segregating in the population under evaluation.     

The effect of an indirect anthelmintic treatment on parasites and breeding success of free-living pheasants Phasianus colchicus

In Great Britain free-living common pheasants Phasianus colchicus are often managed at high densities owing to their popularity as a quarry species. They are prone to infection by a range of parasite species including Heterakis gallinarum, Capillaria spp. and Syngamus trachea. In 1995 the efficacy of an indirect anthelmintic technique for controlling parasitic worm burdens of pheasants was determined in a pilot study on a shooting estate in the south of England. Between 2000 and 2003 a large-scale field experiment was conducted on nine estates in eastern England to determine the effect of the technique on parasite burden and pheasant breeding success. In the absence of anthelmintic treatment worm burdens increased rapidly through March and April, whereas birds given anthelmintic-treated grain had lower worm burdens during the same period. The breeding success of pheasants was significantly higher on plots provided with anthelmintic treatment, although no long-term increases in population densities were observed. The burdens of the most common parasite H. gallinarum were significantly lower in pheasants from treatment plots six weeks after the anthelmintic treatment had ceased, but spring treatment did not influence parasite burden in the following winter.     

Biosynthesis of alkane-2,3-diols: enzymatic reduction of 3-hydroxyoctadecane-2-one to octadecane-2,3-diol by a NADPH (B-side) specific microsomal reductase from the uropygial glands of ring-necked pheasants (Phasianus colchicus).

Cell-free preparations from the uropygial gland of ring-necked pheasant catalyzed the reduction of a synthetic R,S-mixture of 3-hydroxyl[3-¹⁴C]octadecane-2-one (acyloin) to a mixture of threo- and erythro-[3-¹⁴C]octadecane-2,3-diol, the final step in the postulated pathway for the biosynthesis of alkane-2,3-diols. The product of enzymatic reduction was identified by Chromatographic techniques and chemical degradation studies. The acyloin reductase showed a pH optimum near 4.0 and specificity for NADPH. With stereospecifically labeled [³H]NADPH, it was shown that acyloin reductase preferentially transferred hydride from the B-side of the nicotinamide ring to the acyloin. A typical Michaelis-Menten substrate saturation was observed for the acyloin and an apparent K_m of 70 μm was calculated from linear double reciprocal plots. Acyloin reductase was inhibited by thioldirected reagents such as p-chloromercuribenzoate and N-ethylmaleimide. Subcellular fractionation of the gland homogenates using sucrose density gradient centrifugation showed that acyloin reductase activity coincided with NADPH:cytochrome c reductase activity, strongly suggesting that acyloin reductase is localized in the microsomal membranes.     

Detection and characterization of primordial germ cells in pheasant (Phasianus colchicus) embryos

The developmental similarity between the chicken and pheasant (Phasianus colchicus) allows the novel biotechnologies developed in the chicken to be applied to the production of transgenic pheasants and interspecies germline chimeras. To detect pheasant primordial germ cells (PGCs) efficiently, which is important for inducing germline transmission, the ultrastructure of PGCs and their reactivity to several antibodies (2C9, QB2, anti-SSEA-1, and QCR1) and periodic acid-Schiff's solution (PAS) were examined. To obtain PGCs, blood was taken from embryos incubated for 62-72 h or from gonads from embryos incubated for 156-216 h. The PGCs collected from both sources had the typical ultrastructure of pluripotent cells: a large nucleus with a distinct nucleolus, a high ratio of nuclear to cytoplasmic volume, and a distinct cytoplasmic membrane. In comparing the morphology of PGCs collected from different sites, more mitochondria and better-developed membrane microvilli were found in gonadal PGCs than in circulating PGCs. The nucleus of gonadal PGCs was flattened and had a large eccentrically positioned nucleolus. Of the antibodies tested, only QCR1 antibody reacted with an epitope in pheasant PGCs, and no specific signal was detected to other antibodies. The temporal change in the PGC populations in the blood and gonads of embryos was examined. In blood, the population was greater (P < 0.0001) in embryos incubated for 64 h than in embryos incubated for 62 or 66-72 h (31.4 versus 5.6-16.2 microL(-1)). In embryonic gonads, the number of PGCs increased continuously from 156 to 216 h of incubation (193-2,718 cells/embryo), although the ratio of PGCs to total gonadal cells did not change significantly (0.50-0.61%). In conclusion, pheasant PGCs have typical germ cell morphology and possess the QCR1 epitope. Circulating blood and the gonads of embryos incubated for 64 and 216 h, respectively, are good sources of PGCs.     

A note on meat quality traits of pheasants (<Emphasis Type=Italic>Phasianus colchicus</Emphasis>)

Meat yield, proximate composition, pH and drip loss of breast and thigh muscles were studied in 29 hunted male and 32 slaughtered female pheasants. In the breast muscles of additional 14 hunted male pheasants, colour, cooking loss and shear force were measured. Weight of muscles of hunted male pheasants was higher than that of slaughtered females, but the percentages of breast and thigh muscles relative to the dressed carcass did not differ. Average protein concentrations in lean muscles were above 22%, and average fat was below 1.2%. In breast muscles, pH₂₄ was lower than in thigh (ca. 5.6 vs. 6.0), and, consequently, drip loss was higher (2.2-3.0% vs. 1.0-1.5%). Colour of breast muscles was characterised by L*a*b* values of about 55, 4 and 8-9, respectively. The shear force of breast muscles was about 30 N/cm².     

Complete mitochondrial genome of ring-necked pheasant Phasianus colchicus alaschanicus from China's Helan Mountains and description of its phylogenetic relationships in Galliformes

Phasianus colchicus alaschanicus, Phasianidae, Galliformes is known only from the Helan Mountains of Ningxia and Inner Mongolia Autonomous Regions, China. Due to few studies on this subspecies, the taxonomic status of Phasianus colchicus alaschanicus in Galliformes is unclear. We sequenced the mitochondrial genome of one P. c. alaschanicus and downloaded 36 species of 22 genera from GeneBank to construct a phylogenetic tree based on the Maximum Likelihood (ML) method. The mitochondrial genome sequence length of P. c. alaschanicus was 16,688 bp with a base composition of 30.6% A, 25.3% T, 30.8% C, and 13.3% G, including two rRNA genes (12S rRNA, 16S rRNA), 22 tRNA genes, 13 protein-coding genes, and a control region. We confirmed the genetic classification status of P. c. alaschanicus in Galliformes. The Phasianidae formed a complex clade, which could be separated into eighteen lineages. P. c. alaschanicus was a sister group of the remaining taxa (posterior probabilities 100% in ML).     

Expression of claudin-1 and -11 in immature and mature pheasant (Phasianus colchicus) testes

The expression of claudin-1 and -11, tight junctions (TJs) proteins was examined in immature and adult pheasant (Phasianus colchicus) testes. Claudin-1 and -11 cDNA were highly similar to those of human, mice, and chicken. Claudin-1 mRNA and protein (21 kDa) levels in immature testes were higher than those of adult testis. In immature testes until 6 weeks of age, Claudin-1 was found at contacts between adjacent Sertoli cells and between Sertoli cells and germ cells. In adult testis, Claudin-1 was found in early spermatocytes migrating the blood testis barrier (BTB). Blood vessels were positive for claudin-1. Claudin-11 mRNA and protein (21 kDa) increased during adulthood development of testis. In immature testis, Claudin-11 was found in apicolateral contacts between adjacent Sertoli cells, indicating its involvement in cell adhesion in immature testis. In adult testis, strong wavy Claudin-11 immunoreactivity was parallel to basal lamina at the basal part of seminiferous epithelium, indicating that Claudin-11 at the inter-Sertoli TJs may act as a structural element of the BTB. Weak Claudin-1 and -11 immunoreactivity at contacts between Sertoli cells to elongating/elongated spermatids, meiotic germ cells, and basal lamina suggests that they also participate in the cell-cell and cell-extracellular matrix adhesion in pheasant testis. Testosterone increased claudin-11 mRNA in testis organ culture and Sertoli cell primary culture, suggesting positive regulation of claudin-11 gene by androgen in Sertoli cells of pheasant testis. This is the first report on the claudins expression at BTB in avian testis.