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The abnormality resulting in legless condition which appeared in one pedigree mating in the R.I.R. stock is reported. The condition was lethal to the affected embryos between five and seven days of the incubation period. The matings carried out suggested that the condition was not hereditary but since only two males were raised from the original mating it cannot be stated with certainty.
Because of the paucity and inconsistency of information on blockage of the chicken autonomic nervous system for extended periods, the effects of atropine, phenoxybenzamine and propranolol in the anesthetized hen were examined. It was found that cholinergic blockade by atropine was very short lived. For effective (80%) parasympathetic blockage a priming dose of 0.25 mg./kg;, followed by an infusion at the rate of 17.5 microgram/kg./min., was required. Similarly, inhibition of the beta-sympathetic system required propranolol in a priming dose of 0.25 mg./kg. and an infusion of 5 microgram/kg./min. The alpha-sympathetic inhibitor, phenoxybenzamine, was effective when given as a single dose of 5 mg./kg. Using these levels of inhibitor it was possible to ensure blockade in all cases for periods of two hours or more.
Five experiments were conducted to determine the influence of potassium iodide (KI) on serum calcium in the laying hen. Serum calcium was significantly increased when hens were fed a diet containing 5000 p.p.m. I as KI. This occurred even though feed consumption, egg production and size of ovary and oviduct were significantly decreased. In some hens fed KI, serum calcium was increased to as high as 70 mg. %, a 163% increase. Most of the increase was in the form of non-diffusible calcium. Hens fed a diet containing 0.05% calcium had significantly reduced serum calcium values. When these calcium-deficient hens were fed 5000 p.p.m. I as KI, a significant increase in serum calcium occurred within 3 days and within 7 days their average serum calcium value was significantly greater than that of hens fed a diet containing 3.00% calcium. A combination of KI plus estradiol was significantly more effective in increasing serum calcium than was either compound alone. Although these data gave no indication as to the mechanism of action of KI on serum calcium they do offer a new model in which to study calcium metabolism in the laying hen.
Adult, male Single Comb White Leghorn chickens (SCWL) were housed unrestrained in individual cages in a controlled environment room with a photoperiod of 12L:12D. By means of surgically implanted radio transmitter, body temperatures were recorded hourly for five consecutive days at each of six experimental temperatures: 23, 26, 29, 32, 35, and 38 C. The data were evaluated statistically by correlogram, periodogram, and harmonic analysis. Period length of each cycle was about 24 hr at all ambient temperatures. No significant differences in deep body temperature were observed until the ambient temperature reached 32 C; but highly significant increases were detected between 32, 35, and 38 C. Diurnal differences in body temperature ranged from .6 to 1.1 C. It has been suggested that the body temperature of male chicken may be under the control of a biological clock that synchronizes with the solar day.
The basic vitamin requirements of the bird must be more clearly established before the true effects of temperature can accurately be measured. Although the literature reveals progress, the knowledge gained (as in many other fields of scientific investigation) is spotty, contradictory, vague, and intriguing, providing a basis for further planned comprehensive investigation. A review of literature leads to some general conclusions on the effects of temperature on vitamin requirements. 1) Feed consumption regulates vitamin intake, and feed consumption is closely moderated by environmental temperature, both high or low and to a varied extent. 2) Factors involved in management, growth, egg production, light, etc. are very influential interactions. 3) High environmental temperature and subsequent heat stress will result in altered availability and utilization of specific nutrients. 4) There are factors regulating nutrient intake that relate to utilization, such as energy-protein ratio, management, age of bird, and genetic composition of the bird. 5) Care and treatment of feed, age, storage conditions, pelleting, and characteristics of the ingredients are important influences.
The tricolored plumage patterns known as speckled, mille fleur, porcelain, and spangled (Old English Game type) were studied along with the black and white mottled plumage pattern. Crosses between birds carrying these phenotypes showed the mo gene to be common to all of these plumage color patterns. Crosses between Speckled Sussex and Black-tailed White Japanese Bantams resulted in a new plumage color pattern in which silver replaced gold to change a tricolored to a bicolored pattern. The recessiveness of the mo gene was verified by crossing birds of the wild-type plumage coloration which differed only at the mo locus. Also, a hypothesis for the gene action of mo is offered to account for the many different phenotypes produced by it.
Twenty-two cockerels were adenohypophysectomized by the improved transbuccal approach to observe histological changes in the testis during 60 postoperative days. Total adenohypophysectomy induced a collapse of spermatogenic cells and a decrease in the diameter of seminiferous tubules, accompanied by a rapid decrease in testicular weight. The patterns of degeneration of various spermatogenic cells were different from each other. Spermatozoa and spermatids were detached from the epithelium by day 5, spermatocytes by day 10, and more than half of spermatogonia by day 20 after the operation. Sertoli cells reduced their cytoplasmic processes on day 3 but still retained their height to sustain an indented form of epithelium between days 3 and 10, when most spermatogenic cells were disengaged from the epithelium. Sertoli cells were never sloughed off into the lumen. On and after day 20, seminiferous epithelium was monolayered, consisting of atrophied Sertoli cells with small sized nuclei and spermatogonia. Interstitial cells tended to agglomere maximum on day 60. Interstitium occupied more than 30% of estimated total volume of testis from day 20 onward. According to the observation on day 30, the degree of degeneration of seminiferous tubules in later stages depended on the location within the testis. The network of cytoplasmic processes of Sertoli cells persisted in the central but not in the peripheral region.
Five chromosomal rearrangements involving chromosome 1 were utilized to test linkage relationships of the blue egg--pea comb--naked neck (O-P-Na) linkage group. An F1 stock was created by crossing rearrangement carriers with individuals carrying the traits being studied. The F1 was then backcrossed to recessive, normal chromosome tester stocks. Chromosomal and phenotypic descriptions were made for each of the segregating progeny. Significant linkage relationships were shown for blue egg and pea comb on the proximal one third of the short (p) arm of chromosome 1. No linkage was found for naked neck. Barring and silver were tested against the two arms of the Z (sex) chromosome, and the linkage values suggest that these loci are on opposite arms. Blood group loci linkages between Ea-H and W4, Ea-P and Na, and Ea-A and Ea-E were confirmed. However, no linkage was observed between these loci and the marker rearrangements on the p arm of chromosome 1.
The effect of epinephrine, phenoxybenzamine (alpha-receptor blocker), and propranolol (beta-receptor blocker) on the oviductal motility in an in vitro system was investigated in strips from infundibulum, magnum, isthmus, and uterus from laying hens. Epinephrine resulted in a significant (P less than .05) contraction of both infundibulum (+166.6%) and magnum (+70.3%) and relaxation of the uterus (-56.9%), while the response of the isthmus was inconsistent. Epinephrine induced contractions in propranolol blocked strips in all four oviductal segments studied (infundibulum, +138.1; magnum, +70.4; isthmus, +35.9; and uterus, +30.1%). Epinephrine, in phenoxybenzamine-blocked strips, resulted in relaxation of all segments (infundibulum, -27.5; magnum, -40.5; isthmus, -63.4; and uterus -53.6%). These results suggest that the activity of alpha-excitatory adrenergic receptors is greater in the anterior than in the posterior segment of the oviduct. conversely, greater activity of beta-inhibitory receptors seems to be present in the posterior than in the anterior segment of the oviduct.
The effects of environmental temperature on serum estradiol, progesterone, and calcium concentration in White Plymouth Rock pullets were investigated from 12 to 24 weeks of age. Pullets were grown from 10 weeks of age in individual cages at constant environmental temperatures of 13 C, 25 C, or 35 C. Serum estradiol land progesterone concentrations were measured by the use of radioimmunoassay. Serum calcium was measured by an atomic absorption spectrophotometer. There were no significant differences in growth rate or concentration of serum estradiol, progesterone, or calcium between pullets kept at 13 C and 25 C. There was a marked increase in serum estradiol and calcium concentration before onset of lay. There were high correlations between serum estradiol and calcium concentration in pullets kept at 13 C (r = .803) and 25 C (r = .813). Progesterone concentration in pullets kept at 13 C and 25 C reached a peak at 20 weeks of age. By contrast, pullets kept at 35 C had significantly lower growth rates and lower concentrations of serum estradiol, progesterone and calcium than those kept at the other two environmental temperatures. The high environmental temperature of 35 C inhibited growth and delayed sexual maturation of pullets.
Carbon particles suspended in saline were injected into the vagina, the uterus, or into the magnum, 5 to 10 or 50 to 55 min after an oviposition. Carbon particles injected into the uterus 5 to 10 min postoviposition reached the infundibulum within 5 to 10 min, and particles introduced 50 to 55 min after an oviposition were not transported to the anterior oviduct. When particles were injected intramagnally 50 to 55 min following an oviposition, they moved distally toward the uterus. Particles introduced into the uterus 5 to 10 min after an oxytocin-induced oviposition were transported to the anterior oviduct. Carbon particles deposited into the vagina remained in situ irrespective of the time deposited. These results suggest that a special oviducal movement, which is though to be caused by oviposition, participates in spermatozoal transport through the hen's oviduct.
A comparative study has been made of the accumulation and synthesis of cholesteryl esters in the liver, yolk sac membrane, and yolk contents of the chick embryo during the last week of development. This involved a comparison of the cholesteryl esters synthesized during incubation in vitro with 14C-cholesterol with those accumulated during incubation in vivo. Results indicated that the considerable accumulation of cholesteryl esters, mainly cholesteryl oleate, that occurred within the liver during embryo development arose from synthesis in the yolk sac membrane. This suggested a specific role in the transport of yolk lipid into the embryo. With the approach of hatching the ability of the liver to synthesize its own cholesteryl esters increased while that of the yolk sac membrane decreased.
The purpose of this study was to examine the maturation of the avian corticosterone diurnal rhythm in relation to other indices of adrenocortical maturation. Female chickens were studied at 1, 5, 11, 17, 23, and 55 weeks of age. Blood samples were drawn at 4-hr intervals during a 24-hr (14 hr light: 10 hr dark) photoperiod. The diurnal rhythm in corticosterone concentration was not apparent until 11 weeks of age. At this age, unlike at 17 weeks of age, the maximal corticosterone concentration occurred during the light period. This indicates that although a rhythm is present at 11 weeks, a phase shift apparently occurs before the adult-like diurnal rhythm is attained. Injection of adrenocorticotropin (ACTH) produced an increase in the circulating corticosterone concentration in chickens at all ages. These results indicate 1) a phase shift must occur between the time of the initial emergence of a diurnal corticosterone rhythm and the attainment of the characteristic adult-like diurnal rhythm, and 2) the avian adrenal cortex is capable of responding to an ACTH stimulus with an increase in circulating corticosterone before the central nervous system rhythmically controls the pattern of circulating ACTH or corticosterone.
Two experiments using 64-week-old Single Comb White Leghorn roosters were conducted to determine the meal response to an abrupt change in dietary energy or environmental temperature. In the first experiment, dietary energy level was changed from 200 kcal to either 250 or 150 kcal/75 g. In the second experiment, environmental temperature was changed from 22.2 C to either 13.3 or 30.0 C. Feeding behavior was recorded throughout both experiments. Meal size, meal frequency, and time spent eating a meal were measured. Roosters changed to high-energy or low-energy diets consumed low or high amounts of feed, respectively. Those fed the high-energy diet tended to decrease meal size and meal duration and to increase the number of meals. Roosters changed to the low-energy diet decreased meal size and meal duration and increased the number of meals eaten. The results tend to confirm the chemostatic mechanism in birds as food intake was related to energy in the diet. Roosters changed to high or low environmental temperature responded by decreasing or increasing their feed intake, respectively. Roosters changed to a high environmental temperature significantly decreased meal size, meal duration, and increased the number of meals. Those changed to a low environmental temperature significantly increased meal size and decreased meal frequency and meal duration.
Nephrons in the avian kidney have an extremely heterogeneous size distribution. The shortest nephrons have very small glomeruli, and the larger nephrons have very large glomeruli. Physiological, nutritional, and disease factors may be correlated with the functioning of different sized nephrons. The present study was conducted to compare two techniques for measuring glomerular size distributions. A postmortem India ink infusion technique gave results that were highly comparable to an in vivo alcian blue infusion technique. Single Comb White Leghorn pullets were found to have approximately 270,000 glomeruli per kidney; glomerular circumferences and diameters ranged between .07 to .42 mm and .02 to.14 mm, respectively. A unimodal size distribution was found, with most glomeruli falling within the circumference range of .15 to .26 mm. The alcian blue technique should provide a quantitative in vivo method for evaluating selective tubular damage or physiological glomerular intermittency.
Neonatal development, as influenced by the autosomal albino (ca/ca), recessive white (c/ca), or colored (C+/-) genotype, was investigated. Albino chicks exhibited smaller (P less than or equal to .005) body weights at 3, 6, and 9 days of age. A significant (P less than or equal to .005) reduction in growth rate also occurred in albinos from hatching to 3 days of age. Associated with the suppression of growth was the retention of greater (P less than or equal to .05) amounts of yolk sac contents. Albino chicks exhibited smaller (P less than or equal to .01) bursal weights at hatching and 6 days of age. Plasma glucose and protein levels were depressed (P less than or equal to .005) in albinos at hatching when compared to recessive white or colored chicks. No significant differences in plasma glucose or protein were noted at any other time periods. These data provide evidence for the retardation of neonatal development and a reduction in maternal yolk utilization by the ca/ca embryo. We suggest that there may exist additional physiological functions for melanin/functional tyrosinase that are not directly involved with pigmentation.
Serum prolactin (PRL) and luteinizing hormone (LH) levels were measured in White Leghorn hens induced to pause by fasting and exposure to 8L:16D photoschedule. Both PRL and LH levels declined during the fast and increased upon refeeding. Prolactin levels changed primarily in response to the fasting/refeeding component of the pause-inducing procedure, as exposure of non-fasted hens to an 8L:16D photoschedule exerted little effect on serum PRL levels. Injections of ovine prolactin during the pause-inducing procedure significantly reduced the subsequent rate of loss of primary wing feathers, suggesting that in certain physiological states, PRL may function to suppress molting.
A previously published technique for producing renal insufficiency in chicks involves ligating the caudal renal vein together with the ureter near the midpoint of the kidney. This ligation occludes the normal route (caudal renal vein) by which blood exits the medial and posterior kidney divisions. The present study was conducted to evaluate kidney function following chronic caudal renal vein and ureter occlusion. The ureters and caudal renal veins of 2 to 3-week-old chicks were clamped with hemostatic clips (Clamp Group), and kidney function evaluations were conducted when the birds reached 14 weeks of age. Plasma values [osmolality, Na, K, Ca, inorganic P (Pi)] of control, sham, and clamp groups did not differ significantly. Plasma uric acid concentrations did not differ when the control and clamp groups were compared. Clamping the ureter near the midpoint of the kidney caused a significant reduction in the number of filtering glomeruli per kidney, but due to compensatory hypertrophy the kidney weights of the groups did not differ significantly. Kidney function comparisons (urine flow rates, glomerular filtration rates, renal plasma flow rates, urine pH, fractional excretion of Na, K, Ca, Pi, and uric acid) revealed a significant reduction in Na and K excretion by the clamp group, but other renal function parameters did not differ significantly. These experiments demonstrate that chickens have a remarkable capacity to survive significant reductions in renal mass and to adapt to major disruptions of blood flow patterns.