Roger A. McNabb

The development of thermoregulatory ability, heat seeking activities, and thyroid function in hatchling Japanese quail (Coturnix coturnix japonica)

SummaryThermoregulatory ability of precocial Japanese quail hatchlings was examined by measuring their cooling rates during exposure to 30 ° C for 30 min. From day 3 to day 11 after hatching, the cooling rates decrease, which indicates an increase in thermoregulatory ability during this period. By 13 to 15 days after hatching the quail appear to be homeothermic but regulate their temperature at levels below typical adult body temperatures (Figs. 2, 3).Heat-seeking activity, as indicated by the time per day they kept a heat lamp operating, decreased markedly from 3 to 11 days of age, then did not change further from 11 to 16 days of age (Fig. 4). Quail chicks raised in a thermal gradient achieved adult body temperatures at 13 days of age.Body weight increased 6.0 X, surface area increased 3.8 X, and plumage weight per unit of surface area increased 4.4 X during the first 16 days after hatchings (Figs. 5, 6).Histological studies (thyroid follicle cell heights, colloid diameter, colloid staining properties) and stable iodine analyses indicate that the time course of developing thyroid function parallels the time course of developing thermoregulatory ability (Figs. 7, 8). From 3 to 5 days after hatching until 13 days after hatching the chicks show increased resistance to cooling and hormone release from the thyroid gland exceeds hormone production (Fig. 8). Between 13 and 15 days of age, the chicks appear to be homeothermic and some thyroid parameters approach adult levels. These results suggest that the activity of the thyroid gland is an important factor in the development of thermoregulation in Japanese quail chicks.

Urate and cation interactions in the liquid and precipitated fractions of avian urine, and speculations on their physico-chemical state

1. 1. Bird urine typically consists of two fractions : a supernatant liquid and an insoluble, precipitated fraction. 2. 2. We have examined the concentration of Na+, K+ and NH4+ and urate in these two fractions in urine from roosters given diets of different protein content and drinking solutions of different NaCI concentration. 3. 3. In liquid urine the concentrations of Na+ and NH+4 are high enough to suggest that urate must be present in the form of lyophilic colloids, stabilized by some additional components of the urine. 4. 4. Abundant precipitated urate appears to aid in the excretion of Na+ and K+, butnot of NH4+.

Physiological chemistry of uric acid: Solubility, colloid and ion-binding properties

Abstract 1. 1. In vitro , interactions between common cations (Na + , K + , NH + 4 , Ca 2+ and Mg 2+ ) and excess uric acid were examined. 2. 2. Each of these cations reduced the solubility of uric acid over time; the reductions produced by NH + 4 , Ca 2+ and Mg 2+ were most rapid and complete. 3. 3. Each of these five cations became incorporated into excess, undissolved uric acid. These ion incorporations apparently did not result in monobasic urate salt formation; the reasons are discussed. 4. 4. Na + and K + exhibit competition for inclusion into excess undissolved uric acid; K + can displace Na + from uric acid in protein free systems, but not when 1% avian plasma is included in the buffer. 5. 5. Under a variety of circumstances, the excess uric acid can be transformed from angular crystals into small spheres or needles. The spheres are similar to those present in avian and reptilian urine, insect fat body and snail kidney. 6. 6. The presence of avian plasma proteins can alter both the final structural form of excess uric acid and the extent to which it can include cations.

The effects of dietary protein content on water requirements and ammonia excertion in pigeons,Columbia livia

Abstract 1. Ad lib. drinking rates, minimum water requirements, and the rates of urine flow and ammonia excertion in the pigeon vary directly with the dietary protein content. 2. Increased dietary protein content does not alter qualitatively the physiological handling of excretory ammonia. 3. Restriction of water availability fromad libitum drinking to minimum water requirements alters the physiological handling of excretory ammonia and may alter the proportion of nitrogen excreted as ammonia.

Urate excretion by the avian kidney.

Abstract 1. 1. Our work does not support fully the idea that uric acid and urate nitrogen excretion is solely a device for the economical elimination of waste nitrogen by birds. 2. 2. It may participate significantly in renal cation excretion as well. 3. 3. Moreover, the presence of precipitated constituents in urine may render invalid the use of conventional osmotic U P ratios as the sole indicator of renal concentrating abilities of birds.

The excretion of urate and cationic electrolytes by the kidney of the male domestic fowl (Gallus domesticus)

SummaryFour groups of roosters were obtained from combinations of high and low protein diets (33% or 11%), and two drinking solutions (tap water or 1% NaCl solution). Ureteral urine was analyzed for urate, Na+ and K+, in both the liquid and precipitated fractions of the urine.Birds fed a high protein diet-salt water combination excreted unusually large amounts of urate. In all groups, most of the excreted urate was in the form of a precipitate. This precipitate also contained large amounts of Na+ and K+ (Table 2).The presence of abundant urinary urate, due to high protein diet and large NaCl intake, aids in the excretion of Na+ and K+, by reducing their contribution to the osmotic pressure of the urine. However, some of these cations, although present in the urine precipitates, do not appear to be in the form of monobasic urate salts. The significance of urate in the excretion of electrolytes is discussed.

The effects of changes in dietary protein and water availability on urinary nitrogen compounds in the rooster, Gallus domesticus--I. Urine flow and the excretion of uric acid and ammonia.

Abstract 1. 1. Increased dietary protein content caused increases in the rates of drinking, urine flow, uric acid excretion and ammonia excretion of roosters. Urinary uric acid concentrations increased while ammonia concentrations remained constant, which resulted in changes in the distribution of nitrogen between these components. 2. 2. Water restriction caused an increase in the proportion of the urinary nitrogen excreted as ammonia and a decrease in the proportion excreted as uric acid. Thus, our results do not support the generalization that increasing the excretion of uric acid is an adaptive means by which birds minimize excretory water loss under limited water conditions.

Skin and plumage changes during the development of thermoregulatory ability in Japanese quail chicks

Abstract 1. 1. Measurements of heat transfer across skin-feather pelts of Japanese Quail chicks (Coturnix coturnix japonica) indicated a 22% increase in insulative capacity during the first 13 days after hatching. The molt from down feathers to the first juvenile plumage occurred during this time. 2. 2. Skin permeability decreased to adult levels by 13 days of age. This appeared to be due to an increase in thickness of the cornified layer of the epidermis.

Thyroid function in embryonic and perinatal Japanese quail

Abstract Thyroid function in Japanese quail embryos is similar to that of domestic fowl embryos, suggesting the existence of a common pattern of thyroid development in precocial birds, regardless of differences in body size. From 10 to 15 days of incubation there are steady increases in the capacity for hormone production and release, but circulating triiodothyronine (T 3 ) and thyroxine (T 4 ) concentrations are low. During the perinatal period hormone secretion rises sharply. Serum concentrations of both T 3 and T 4 are significantly higher in embryos that have penetrated the chorioallantoic membrane than in ones that have not. Thus high thyroid hormone concentrations are associated with the beginning of pulmonary respiration and the high metabolic demands of the hatching process.

The effects of changes in dietary protein and water availability on urinary nitrogen compounds in the rooster, Gallus domesticus—II. Diurnal patterns in urine flow rates, and urinary uric acid and ammonia concentrations☆

Abstract 1. 1. Excretory parameters of roosters exhibit diurnal patterns of variation that are altered by changes in dietary protein, water availability and time of feeding. Patterns of urine flow rate are influenced most by changes in water availability, while patterns of urinary uric acid and ammonia concentration are altered most by changes in dietary protein content. 2. 2. Urinary flow rates and uric acid concentrations are inversely related for individual time periods. 3. 3. Changes in feeding time altered some excretory parameters but did not result in a predictable pattern of changes.