Mercury toxicity as compared to adrenocorticotropin-induced physiological stress in the chicken.
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Adrenocorticotropic Hormone↗
Biomedical subjects
J Brake
Publications and source records attributed to J Brake.
Physiological changes in caged layers during a forced molt. 4. Leucocytes and packed cell volume.
Packed cell volume and circulating leucocyte numbers in force-molted, Single Comb White Leghorn (SCWL) hens were examined. Two groups of SCWL hens, reared under commercial conditions, were subjected to force molting (FM) at 70 (Trial 2) and 72 weeks of age (Trial 1). The force molting procedure consisted of a reduced photoperiod (6 hr), feed removal for 12 days (Trials 1 and 2), and water withdrawal for 1 day (Trial 1 only). Cessation of egg production was achieved in 6 days. Control (CON) hens were maintained in each trial with no change in daylength, and feed and water were available ad libitum. The FM hens exhibited a significant increase in packed cell volume (PCV) from the time of feed removal until immediately prior to resumption of egg production. This effect was not associated with water deprivation. The FM hens exhibited numerically increased numbers of total leucocytes (TWBC) and monocytes throughout the nonlaying period. However, the increase was significant on Day 14 of both trials for TWBC and on Days 21 and 35 (Trial 1) and Days 14 and 48 (Trial 2) for monocytes. A significant eosinophilia was observed on Days 7 and 14 of both trials. Changes associated with lymphocytes, heterophils, and basophils were inconsistent. Lymphocytes were increased significantly in the FM hens of Trial 2 from Day 21 to Day 48, but no significant difference occurred in Trial 1. A heterophilia was exhibited by the FM hens of Trial 1 on Days 7 and 14, but not in Trial 2. Conversely, a significant basophilia was observed on Days 7 and 14 in Trial 2, but not in Trial 1. These data suggested that an increased PCV, eosinophilia, and possibly increased TWBC and monocyte numbers were associated with a forced molt in caged SCWL hens.
Animals↗
External bone volume, ash, and fat-free dry weight of femurs of laying hens fed diets deficient or adequate in phosphorus.
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Animal Feed↗
Recrudescence of the thymus and repopulation of lymphocytes during an artificially induced molt in the domestic chicken: proposed model system.
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Animals↗
Effect of mercury toxicity on serum osmolality, plasma sodium and potassium, and serum proteins in the chicken.
Juvenile male chickens were exposed continuously to 300 micrograms/ml of mercury (Hg) in the form of mercuric chloride (HgCl2), via the drinking water, from hatching through six weeks of age. Serum osmolality and plasma potassium were increased significantly as a result of the Hg treatment. Plasma sodium was increased numerically in two of the three trials. Of the serum proteins, only albumin and the transferrins exhibited a consistent significant increase. It is concluded that alterations in serum ions and proteins account for the significant increase in plasma osmolality. The increase in transferrins may represent a mechanism to bind and detoxify Hg.
Animals↗
Physiological changes in caged layers during a forced molt. 1. Body temperature and selected blood constituents.
The effects of forced molting on body temperature and selected blood constituents were studied. Caged layers, reared under commercial conditions, were force molted successively at 72 and 104 weeks of age. This was accomplished by removing feed for up to 12 days and water for up to 3 days while simultaneously reducing the day length to 10 hr or less. This procedure resulted in a cessation of egg production within one week of the initiation of feed removal. There was a significant increase in body temperature during feather loss and renewal. Packed cell volume and hemoglobin increased significantly immediately upon removal of feed and water and remained elevated above control levels for the duration of the pause in egg production, while plasma total calcium, and inorganic phosphate decreased significantly during the corresponding period. Plasma total protein and plasma glucose did not exhibit consistent trends. Body temperature and the levels of the measured plasma consituents returned to normal levels upon the resumption of egg production.
Animal Feed↗
Physiological changes in caged layers during a forced molt. 2. Gross changes in organs.
The effects of forced molting on body weight and the absolute and relate weights of the liver, ovary, oviduct, right adrenal, and spleen were studied. White Leghorn hens which were reared and maintained under commercial conditions were force molted by reducing daylength as well as by withdrawing feed and water. This procedure induced a pause in egg production within one week of the initiation of feed removal. Four trials were conducted. In Trial 1 the hens were sampled at weekly intervals for 56 days beginning at the time feed was removed. In Trials 2, 3, and 4 the hens were sampled either daily or on alternate days for up to 22 days beginning at the time of feed removal. The absolute and relative weights of the liver, ovary, and oviduct were decreased significantly. Body weight decreased consistently. No consistent trend over the four trials was found in the absolute or relative weights of the right adrenal or the spleen.
Adrenal Glands↗
Physiological changes in caged layers during a forced molt. 3. Plasma thyroxine, plasma triiodothyronine, adrenal cholesterol, and total adrenal steroids.
The effects of forced molting on plasma levels of thyroxine (T4), triiodothyronine (T3), and adrenal cholesterol and total adrenal steroid content were studied. Commercially available strains of Single Comb White Leghorn (SCWL) hens, reared and maintained under commercial conditions, were used in the three trials. The hens were moved to environmentally modified facilities prior to the forced molt which was accomplished by reducing daylength and by withdrawing feed and water. Egg production ceased within one week of initiation of this procedure. The hens were sampled either daily or an alternate days for up to 22 days beginning at the time of feed removal. Plasma T4 initially decreased upon removal of feed, but increased above control levels by the sixth day of feed withdrawal. Plasma T3 levels remained relatively constant throughout the feed withdrawal period. Resumption of feeding with a fortified ground corn ration resulted in a decrease in T4 and concomitant increase in T3. Changes in adrenal cholesterol and total adrenal steroids were not consistent. However, there was a trend toward increased total adrenal steroids during feed withdrawal, and an increase in adrenal cholesterol upon the resumption of feeding.
Adrenal Cortex Hormones↗
The excretory system of young chickens experiencing mercury toxicity--effects on kidney development, morphology, and function.
Four trials were conducted to determine if toxic levels of mercury affect kidney development, morphology, and renal function. Mercury, administered via the drinking water as mercuric chloride caused a reduction in gross kidney weight, an increase in relative kidney weight and a slight but significant increase in the percentage water retained by left kidney of 6-week-old cockerels. Mercury had no effect on renal function of 6-week-old birds as indicated by the clearance of phenol red from circulation. Histological discontinuity of the kidney was extensive and evidenced by foamy cell degeneration and nuclear pyknosis. Although mercury caused gross alterations in the morphology of the kidney, normal excretory function was maintained.
Animals↗
Mercury induced cardiovascular abnormalities in the chicken.
Juvenile chickens were either chronically exposed to 300 microgram/ml of Hg in the drinking water (chronic dosage--CD) or acutely exposed to either 3 mg of Hg/kg body wt (acute low dosage--ALD) or 12 mg of Hg/kg body wt (acute high dosage--AHD) administered intramuscularly for five consecutive days. Only the CD and AHD treatments retarded normal growth. Relative heart weights were increased by the CD treatment, decreased by the AHD treatment, and remained unchanged during the ALD treatment. Relative aorta weights were increased by the CD treatment but decreased by the AHD treatment. ECG analyses revealed a consistent decrease in the amplitude of the R-S and T waves with the greatest effects present in the acute (ALD and AHD) treatments. Histological examination revealed that Hg caused myocardial histopathological changes characterized as a myocarditis with polymorphonuclear and lymphocytic infiltration and fatty degeneration. It is concluded tha Hg causes cardiovascular disturbances in chickens even when administered at levels which do not inhibit normal growth.
Animals↗
Immunosuppression in chickens by passive transfer of preparations of specific immunoglobulins.
The immunosuppressive effects of passive transfers of specific immunoglobulin preparations obtained from immune or hyperimmune sera were evaluated in chickens which were challenged with sheep red blood cells. The data indicate that IgY, fractionated from immune sera, and IgY and IgM, fractionated from hyperimmune sera, when passively administered at the doses employed in this study resulted in antibody-mediated suppression.
Animals↗
Enhanced immunosuppression in bursectomized chickens by passive transfer of antibody.
Three trials were conducted using commercial broiler cockerels to determine the immunological consequences of passive transfers of immune sera to bursectomized chickens. The data illustrate that passive transfers of immune sera to juvenile chickens which had been surgically bursectomized immediately after hatching caused a suppression of the primary hemagglutination response which was greater than that caused by bursectomy or passive transfer of immune sera alone. However, when these same birds were given a secondary challenge of antigen the resulting secondary hemagglutination response was normal. These data indicate that the passive transfer of immune sera to bursectomized chickens greatly limits their ability to mount primary humoral responses, while not affecting the ability to develop anamnestic immunity.
Animals↗