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In the course of some studies on house flies, it became desirable to determine the respiratory exchange of individuals. Since the metabolism of such insects is low, a fairly sensitive apparatus was required. Existing micro-respirometers were not well adapted for use with whole active insects, consequently the apparatus described herein was constructed.

EGGS from individual hens have been shown to be quite uniform with regard to many chemical and structural constituents: The nitrogen, fat and phosphorus content of the yolk (Malcolm, 1901–1902); egg size, shape, and color (Benjamin, 1920); the rate of water evaporation (Dunn, 1923); shell strength (Romanoff, 1929); proportion of thick albumen (Lorenz, Taylor and Almquist, 1934); dry matter (solids) content of albumen (Almquist and Lorenz, 1933); and rate of growth of yolk (Lorenz, 1943). Recent studies on other species such as man and rat (Williams and others, 1951) and the dairy cow (Hancock, 1950) indicate that the intensity of many, if not all, metabolic processes are inherent and collectively form a pattern which is characteristic of the animal. The nature of the environment is known to affect the composition of the egg, and is even more influential than heredity on variation in egg production (Gutteridge and O’Neil, 1942)… .

The effects of the ingestion of diets containing different concentrations of protein on the remaining kidney in adult white rats after a unilateral nephrectomy has been studied. In the animals on the high protein diet (85 per cent casein), actual glomerular and tubular lesions were observed in the kidneys of animals maintained for 90, 120 and 150 days after nephrectomy. In the animals on the standard ration, 18 per cent casein, no significant renal lesions were observed within the experimental period. Spontaneous focal lesions in the kidneys of rats maintained on Sherman's diets "A" and "B" were inconspicuous at the age of 350 days but became progressively more frequent and were commonly observed after 500 days. The animals on the high protein and standard rations were all under 350 days old at the completion of the experiment. It is suggested that the age factor is of importance in that young animals may have greater powers of adaptation in withstanding the injurious effect of high protein rations. The animals on the high protein ration excreted definitely larger quantities of protein in the urine, and showed a higher incidence of casts in periods roughly corresponding to those in which anatomic lesions were observed than did the rats on the standard diet.

(Received for publication, March 16, 1960) The “citric acid cycle” is now regarded as the final common pathway of metabolism serving as the primary route for the oxi- dation of metabolites. Likewise, the thyroid hormone is con- sidered a major regulatory substance for biological oxidations. It, therefore, seemed logical to study possible quantitative altera- tions in the cycle acids in experimental hypo- and hyperthyroid states. The concentrations of the cycle acids in metabolically active tissues, liver and muscle, were determined in experimental hypo- and hyperthyroid and control rats.

IONIZING radiations have long been known to affect biological systems, and a great many radiation effects have been described (Duggar, 1936; Hollaender, 1954). Biological processes are generally inhibited by ionizing radiations, except at low levels, and the biological response to the irradiations is proportional to the dose (i.e., the quantity of radiant energy absorbed by the tissue or organism). Although the mechanism of action of ionizing radiations is not completely understood, they can be used to great advantage in the study of biological processes. Functional alteration of tissues, resulting from irradiation, may be used to interpret the normal process of the tissue. In a study of the physiological processes that lead to the formation of the egg shell and albumen, the surgically exposed oviduct was irradiated with graded doses of X-rays, and the nature of the post-irradiation eggs determined. This procedure resulted in some changes of egg production rate and …

IN BIRDS, a cycle of development and involution of the reproductive organs generally accompanies the mating season. These changes are associated with a renewal of the plumage (i.e., a molt), but the causal relationships between these processes are not certain (Greenwood, 1936). These natural changes in the reproductive organs have been largely eliminated in the domestic chicken, with eggs being produced more or less regularly throughout the year. The hen, however, retains the capacity for involution and regeneration of its reproductive organs, and this sequence may be induced in a number of ways: by withholding feed and water or by excluding light (Hall, 1946), by thyroid administration (Van der Meulen, 1939), by progesterone administration (Adams, 1955; Shaffner, 1955), or by Enheptin feeding (Pino, 1955). The rate of development of the fowl’s reproductive organs with the onset of sexual maturity has been described (Hafez and Kamar, 1955). The size of the …

SummaryOrgan and body mass changes in restrained adult, male domestic fowl were compared with tissue from control and fasted animals. Body mass loss rate in the restrained animals was 63.5% (p < .001) greater than in the fasted group, yet the two groups recovered at the same rate. Compared with controls and fasted animals, restrained fowl exhibited an increase in size of heart, lungs, kidneys, liver, and adrenals but a greater loss of spleen, superficial pectoral muscle, small intestine, and pancreas masses. Relative water content of organs generally increased in restrained and decreased in fasted animals. The data suggest that restraint—although accompanied by inanition—affects organ and body mass in the domestic fowl in a different way than does fasting.

Summary and ConclusionsArtificial decrease in albumen quality and quantity caused by local X-irradiation of the oviduct reduces the hatchability of eggs. The distribution of embryo mortality is different from that encountered in normal eggs: very early mortality is markedly increased. Chicks from such eggs have a lower hatch weight; however, no effect on subsequent chick growth was observed.

Comparison of two kinds of physiological chronic erythrocytic polycythemias in order to differentiate the specific effect of erythrocytic polycythemia from the general effects of high altitude upon the plasma volume. The two kinds were produced hormonally in female chickens, at sea level, or by protracted high-altitude exposures. It appears that the vascular system of the body may account for an increase in red blood cell mass either by reduction in plasma volume, or by no change in plasma volume, resulting in differential changes in total blood volumes.

IN A previous report (Smith et al., 1957), the weight of the oviduct in the normal laying hen was compared with the secretory state of the magnum, as estimated by the position and condition of eggs found in the oviduct on autopsy. The oviduct was considered “pre-secretory” if it contained a hard-shelled uterine egg since these birds, if not sacrificed, soon would have deposited albumen on a new egg; it was considered “post-secretory” when a soft-shelled uterine or isthmian eggs were found. Assuming that albumen is accumulated in the magnum during the intersecretory period (as is indicated by histological findings; Richardson, 1935), one would expect the weight of the “pre-secretory” oviduct to exceed that of the “post-secretory” oviduct by approximately the weight of the deposited albumen (i.e., 20 gms.). Since this anticipated difference in oviduct weight was not found (Smith et al., 1957), another experiment, reported herein, was carried out …

THE shell gland 1 segment of the avian oviduct transfers water to and deposits a shell about the forming egg. Previous studies of shell gland function involved collection of the secreted fluid by catheterizing this organ while it contained a forming egg (Beadle, Conrad and Scott, 1938). This study was undertaken to determine the effect of the functional state of the shell gland (i.e., the stage of egg formation) and the degree of mechanical stimulation (i.e., catheter size) on the rate of secretion. The process of egg formation has recently been reviewed by Sturkie (1954). The rates at which the various processes take pace and the times of their occurrence in the cycle of egg formation have been reported (Bradfield, 1951). A recent description of the histology of the shell gland is available (McCallion, 1953) METHODS Laying White Leghorn hens from the departmental flock were used in these experiments. Housing birds . . .

In an attempt to explain the discrepancy between the results reported by different investigators on the relation between dietary protein and renal lesions, Moise and Smith1 have postulated that young rats may have greater powers of adaptation than old ones, and accordingly may be less susceptible to the injurious effect of an excessively high protein ration. This suggestion was based upon the observation of Arataki,2 that the formation of glomeruli continues throughout the first hundred days of life, and upon the fact that a very large proportion of the published observations reporting absence of pathologic renal lesions were initiated on young rats. In studies (Moise and Smith1) with adult rats fed adequate diets rich in protein, structural lesions were observed at intervals from 90 to 150 days after unilateral nephrectomy. These lesions included both glomerular and tubular changes. The former consisted in serum in the capsular spaces, proliferation of the epithelium of Bowman's capsule with and without ...

EXTERNAL traits of the hen, in particular the comb, vent, and pubic bones, are used as indicators of current egg production. Comparative descriptions of these traits for layers and non-layers may be found in any standard poultry text. A detailed description is given by Rice et al. (1930), who credit Walter Hogan as first describing the modern method of identifying the laying hen. These external criteria were apparently established by observing pullets as they came into production. There is little or no information on the rate of regression of these external traits when laying stops. The regression of the hen’s reproductive organs, however, has been described in an earlier paper (Smith et al., 1957). The purpose of this study was to determine the changes that occur in these external indicators when the hen has been out of production for varying lengths of time up to 100 days. MATERIALS AND METHODS

Domestic fowl exposed to chronic acceleration (prolonged centrifugation) do not appear to “habituate” to repeated rotatory stimulation, as do similarly treated birds maintained at normal gravity. Chronically accelerated birds frequently exhibit postural or locomotor abnormalities, and such individuals lack a nystagmic response to rotatory stimulation. Submitted on August 21, 1961

SummaryMammary tissue of rats at the end of pregnancy and at the height of lactation was analyzed for dry matter and nitrogen content, and the metabolic rate of this tissue was measured in vitro.Lactation increased the water content of the mammary tissue and the protein content of the mammary dry matter.Lactation did not affect the metabolic rate per unit of fresh tissue in vitro; it increased the metabolic rate per unit of dry matter and decreased the metabolic rate per unit of nitrogen in the tissue.Observations were also made on rats that suckled only 1-3 instead of 6 young; and measurements were taken on rats with 6 young at earlier stages of lactation before full milk production was reached. These indicate a positive correlation between the intensity of lactation and the magnitude of the effect that lactation has on the composition and metabolic rate of mammary tissue.

SummaryCitric acid administered to the rat is absorbed since no extra citric acid appears in the feces and intestinal contents do not destroy it. The albino rat has the ability to completely metabolize maximum non-fatal quantities of free citric acid.

The rate of fasting metabolism depends on the level of previous food intake. In order to measure the influence on the metabolic rate of any condition which lowers the appetite one must therefore reduce the food intake of controls to that of the experimental animals in order to eliminate the influence of food level. The rats whose food intake is thus reduced but whose appetite is not affected may eat their daily ration at once while their pair mates with their decreased appetite on unlimited food supply extend their food intake over the whole day.Table I shows the feeding habit of 18 rats during 12 days. The amounts eaten during the various daily periods are expressed in percent of the daily intake. The behavior of 9 rats that had previously been on a restricted ration was essentially the same as that of their controls whose food intake had never been restricted. The previously restricted rats ate, however, during the first 4 hours of unlimited food supply 17 g of food which is more than their later averag...

X-irradiation of the surgically exposed oviduct of the hen reduces the formation of albumen dry matter (which is composed essentially of protein). Over a dosage range of 0–4000 r, the irradiation effect is logarithmically related to the dose, with the albumen (dry basis) formation being reduced 40% at 4000 r. At higher doses (5000 r) irreversible changes apparently take place, since very few birds so treated return to egg production. Radioinhibition of albumen formation requires direct irradiation of the oviduct magnum tissue and, once established, appears to be more or less permanent. The functional status of the magnum tissue, relative to albumen secretion, at the time of irradiation does not appear to influence the result.

Review of current knowledge, research, and research planning on the influence of gravity upon living organisms. Discussed factors affecting the adaptability of animals to increased acceleration fields include age, sex, posture, and body size. Affected functions and aspects reviewed cover growth and mature body size, body composition, maintenance feed requirements, and feed utilization efficiency. It is expected that research involving the exposure of animals to altered gravity states will lead to new biological concepts of very broad importance.

Conclusions1. Tissue respiration studies show that oxygen consumption rate of mature chicken liver slices fits body weight-tissue metabolic rate relationship derived by Kleiber (5) for mature mammals. The oxygen consumption rate of mature chicken kidney slices, however, is much lower than that of mature mammals(7). 2. The relationship between tissue and whole animal metabolic rate in growing chickens is different for the kidney and liver. The Qo2 of kidney tissue (homogenate or slice) is essentially the same for all age groups of birds tested. The Qo2 of liver tissue in vitro is the same for very young and mature birds, but is significantly higher in one-month-old birds. This same sequence has been noted by Kleiber(2) in the whole animal metabolic rate (per unit weight) of growing birds.

On the basis of 926 respiration trials, metabolic rates of normal female rats are presented as means of 42 different age groups from birth to 1000 days of age. The means with their standard errors are given for the metabolic rates per rat, per kilogram weight, per unit of the 2/3 power of body weight (surface), and per unit of the 3/4 power of body weight (inter specific unit of metabolic body size). A minimum of 72.6 Cal/kg.3/4 occurs between the ages of 200 and 300 days. An equation with two exponentials predicts the metabolic rate of rats from 77–1000 days of age with a standard deviation between prediction and observation of 2.2% of the mean.

THE use of human radio-iodinated (I131) serum albumin in birds as a method for determining whole body blood volumes has been reported previously by others (Kotula and Helbacka, 1966; Portman et al., 1952). It has also been used in our laboratory as a method to determine blood volumes in chickens. Human radio-iodinated serum albumin (I131) has been recommended for the determination of plasma volume (directly) and blood volume (indirectly) in humans. Since it is not foreign to the human body, the loss rate is slow; i.e., limited to the rate of metabolization by the body (Abbott, 1966). Its use in other species however probably results in an altered loss rate (Portman et al., 1952). The use of human radio-iodinated serum albumin and its physiological characteristics to determine whole body blood volumes in chickens were investigated and reported herein. METHODS Single Comb White Leghorn adult female chickens were used in this . . .

SummaryIn cockerels raised at high altitude and sea level, and with the sexual development of some repressed by stilbestrol treatment, it is possible to differentiate the erythropoietic effect of androgens and chronic hypoxia. The actions of these factors appear to be independent of each other, a particular level of androgen (indicated by gonad size) producing equal increments in the hematocrit, in either the presence or absence of hypoxia.

The Chinese hazel or litchi nut (Litchi Chinensis) has long been cultivated for medicinal and edible purposes in the Orient, and has attained a certain vogue in this country. A study of the therapeutic and food values of this fruit was made by Read, who describes the nut as “nearly globose with a dull brick-red pericarp which, when ruptured, exposes a sweet, brown, fleshy arillus surrounding a glossy chestnut-brown obicular seed ….”1 If this fleshy edible part corresponds in nutritive value to most of the fruits used in the American dietary, it should constitute a source of certain of the accessory food factors. The present study deals with the assay for vitamins A and B in the litchi nut.Young rats 25 to 30 days old, weighing 40 to 50 grams, were given the following diets:The growth of rats on the first ration was rather prolonged, lasting from 40 to 50 days before cessation. The diet was then irradiated with light from a quartz mercury vapor lamp, with the result that growth was immediately resumed for ...