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Packed cell volume, total leukocytes, total erythrocytes, hemoglobin, mean cell volume and mean corpuscular hemoglobin concentration of the poult were analyzed daily for the first 10 days posthatch. Sexually dimorphic effects on hematological parameters were not apparent, but there was a sex X day interaction for all parameters except hemoglobin indicating that males were slower to develop/respond to critical stimuli. The study revealed a latency in production of erythrocytes and leukocytes in posthatch males and females which coincided temporally with early poult mortality.

The role of reserpine in modifying a primary humoral immune response was evaluated in three experiments with young chickens. It was found that chickens injected with reserpine prior to an intravenous antigenic challenge with sheep red blood cells exhibited an enhanced primary humoral immune response. The enhanced response occurred concomitant with an elevation in adrenal cortical activity as evidenced by the significant elevation of serum corticosterone in the reserpine-treated chickens. These data suggest that both the adrenal cortex and medulla may influence immune responsiveness in the chicken.

Daily body, heart, liver, spleen, pancreas and bursa of Fabricius weights of developing turkey poults were measured. Neither organ nor body weight was affected by sex of the poults during the first 10 days posthatch. Decreases in growth were apparent between days 3 and 6 or 7 and 9 posthatch and coincided with peaks in early mortality.

Eight-week-old broiler cockerels were injected intravenously with avian saline containing additional Na+ as Na Cl or Ca++ as CaC12. After the injections half of the chickens were heated at 45° C. and the others were maintained at 24° C. Cloacal body temperatures were determined and blood samples were collected before heat exposure and at 30 minute intervals until the chickens had been heated for 120 minutes. Na+ did not affect body temperature of chickens in the 24° C. environment, but Na+-treated chickens in the 45° C. environment had significantly elevated body temperatures compared to the heated controls. Ca++ caused a significant decrease in body temperature of the non-heated chickens, but it was without effect in heated chickens. Neither Na+ nor Ca++ altered the responses of plasma glucose, cholesterol, and calcium during the heating episode. However, Ca++ caused a significant rise in plasma inorganic phosphate in non-heated chickens and prevented the rapid decline in the heated chickens. Na+ caused a significant fall in plasma inorganic phosphate in non-heated chickens, but it did not alter the plasma phosphate response to acute heat stress. The present experimental results suggest that Ca++ but not Na+ injection influences body temperature regulation in chickens in a moderate temperature environment, and suggests that Ca++ initially exerts a peripheral rather than a central effect in decreasing the body temperature.

Shells of hatching and nonhatching Large White turkey eggs were examined for magnesium, calcium, and phosphorus content. Eggshells containing embryos that hatched contained significantly (P less than .05) more magnesium than shells from nonhatching eggs. No differences were seen in their calcium content. Eggshells from pipped eggs contained significantly (P less than .05) more phosphorus than shells from eggs that were not pipped or those that hatched. Calcium and magnesium in turkey eggshells declined as time in lay increased. Injections of exogenous magnesium both at setting and transfer significantly (P less than .05) depressed hatchability, whereas exogenous calcium injected at transfer significantly (P less than .05) improved hatchability. Injections of exogenous calcium at the time of setting significantly (P less than .05) depressed hatchability. It was concluded that the mineral content of turkey eggshells may influence embryo physiology and hatchability.

1. The tolerance of chickens to acute heat stress, evaluated by the time required to reach the critical body temperature (Tr) of 44.5 degrees C, was markedly enhanced as the period of fasting was extended. 2. Fasting reduced the rates of heat-induced changes in blood acid-base and electrolyte status. 3. Changes in Tr were correlated with changes in blood pH, pCO2, [Cl-] and [Pi] but not with changes in [Na+] or [K+]. 4. Blood acid-base and electrolyte status were related to Tr rather than time of exposure to heat stress.

The interaction of nutritional status on the tolerance of young chicks to acute heat stress (HS) was investigated. The results of experiment 1 demonstrated that fasting for 24, 48 or 72 hours progressively increased survival time (ST) of chicks exposed to HS. When compared to that of non-fasted (NF) chicks ST more than doubled for 48 and 72 hour fasted chicks. During HS plasma glucose increased in fasted chicks but decreased in NF chicks. Conversely, plasma free fatty acids decreased in fasted chicks and increased in NF chicks. Plasma phosphate of all chicks fell markedly as a result of HS. Chicks of experiment 2 were fed a "carbohydrate-free" diet (CF). Survival time of NF chicks fed CF was significantly greater than that of NF chicks fed a diet containing glucose. The apparent metabolic responses of NF chicks fed CF corresponded to those of fasted chicks of experiment 1. It was suggested that the metabolic substrate utilized by chicks during HS influences ST. The effect of CF diet on ST was also observed in chicks which were fasted for 48 hours prior to HS. Plasma phosphate of chicks exhibiting fasting metabolic responses was not significantly different at heat induced prostration despite marked differences in ST. The results of experiment 3 demonstrated that ST of fasted (24 hour) chicks previously fed a low phosphorus diet was markedly lower than compared to that of fasted chicks fed adequate dietary phosphorus. The effect of diet was found to be dependent on metabolic status since level of dietary phosphorus fed had no effect on ST of NF chicks. The results of the present study indicated that metabolic and nutritional status affect the tolerance of young chicks acutely exposed to high ambient temperature.

Two experiments were conducted to investigate the effect of intravenous injections of bacterial endotoxin in broiler chicks. In both experiments 5-week-old chicks were given a single intravenous injection of either distilled water (control) or 1 mg/kg Escherichia coli endotoxin (serotype 0127:B8) in a volume of 1 ml/kg. In Experiment 1 rectal body temperatures were taken every hour for 24 hr postinjection. In Experiment 2, rectal temperatures and blood samples were taken at 3, 6, 9, 12, 15, and 24 hr following the administration of endotoxin. Hematocrits and plasma glucose, protein, sodium, potassium, magnesium, calcium, and inorganic phosphorus were measured at each time interval. Birds receiving endotoxin showed a significant increase in rectal temperature from 2 hr until 17 hr postinjection. The febrile response was biphasic with temperatures peaking at 3 to 5 hr and again at 9 to 12 hr. No significant changes in hematocrits occurred following endotoxin injection. Plasma protein, potassium, and calcium decreased significantly, while glucose increased significantly after endotoxin administration. No significant changes in plasm a magnesium, sodium, or inorganic phosphorus were observed in endotoxin-treated chicks.

INTRODUCTION The environment in which an animal exists is composed of many interacting factors, each capable, in great enough magnitude, of eliciting a defensive reaction in the animal's biochemical and physiological constitution (Selye, 1963). The environment includes all external factors (temperature, population density, nutrition, light, etc.) as well as internal factors (pathogenic organisms, parasites, or any other foreign substance). Any change in the “environment” will cause both specific and nonspecific responses that are directed at re-establishing a state of homeostasis in the animal. Siegel (1980) presented a general review of physiological stress in birds and pointed out the differences between specific and nonspecific physiological reactions to environmental stressors. Specific reactions are elicited in response to a particular stressor. For example, when an animal becomes hypovolemic there is a decrease in cardiac output, stroke volume, and arterial pressure. The primary compensating mechanisms then are increased heart rate, increased pulse pressure, increased …

Long-Evans rat pups were dosed orally from birth to 21 d with particulate Mn3O4 to obtain a daily dose of 0, 71, or 214 micrograms Mn/body weight . d. Assessments of the hypothalamic, pituitary, or testicular functions were determined by measuring the endogenous or stimulated serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and/or testosterone (T) at 21 or 28 d of age. Body, testes, and seminal vesicles weight and tissue concentrations of Mn were also evaluated. Only slight Mn treatment effects were seen in body and testes weights. No effects were seen either on unstimulated or stimulated FSH or LH serum concentrations. Although no Mn treatment effects were seen on endogenous or 2 h human chorionic gonadotropin (hCG) stimulate serum T concentrations, there was a reduction in the serum T following 7 d of hCG stimulation. The hypothalamic Mn concentrations in animals with these reproductive effects were three times those where alterations in the dopaminergic pathway have been reported. However, no indication of hypothalamic or pituitary malfunction was found. These results suggest that the site of Mn damage that causes depression of sustained serum T concentration is in the testicular Leydig cell.

SUMMARY The serum levels of corticosterone, total calcium, inorganic phosphorus, protein, sodium, and potassium were determined for turkey poults from 1 to 42 days of age. Corticosterone levels were higher at days 10, 14, 21, and 28 in Alcaligenes faecalisinfected turkeys than in uninfected poults. The corticosterone responses in this study indicate that A. faecalis infection stimulates adrenal cortical function even in the very young poult, which ordinarily does not show adrenal cortical responsiveness to various environmental and physical stressors. No differences were observed between infected and uninfected turkey poults in other serum chemistries. RESUMEN

Six hours post-hatch, large white turkey poults were inoculated intranasally with 5 X 10(7) organisms of the "W" isolate of Bordetella avium. Three hours after inoculation and subsequently on days 7, 10, 14, 21, and 28 postinoculation, 30 infected and 30 uninfected control poults were injected intramuscularly with alpha methylparatyrosine (AMPT, 250 mg/kg), and an additional 30 of each group received a saline vehicle. Three hours after AMPT injection, whole brains from treated and untreated poults from both infected and control groups were removed, weighed, and frozen until assayed for norepinephrine (NE), dopamine (DA), and serotonin (5-HT). B. avium-infected poults had a significant reduction in steady-state NE and Da and a greater depletion of NE and DA after AMPT treatment compared with control poults. Infected poults had significantly reduced whole brain 5-HT concentrations, which persisted through 21 days postinoculation. Altered brain NE, DA, and 5-HT concentrations suggest that the B. avium-infected poults may be less able to cope with additional stressors.

The effects of subclinical NH3 toxicity on circulating and regulatory hormone concentrations were investigated in seven Hereford steers. Ammonium chloride (NH4Cl) was infused via a right jugular vein catheter at a rate of 12 mumol NH4Cl.kg BW-1.min-1 for 240 min. This was preceded (PRE) and followed (POST) by saline infusions of 120 and 180 min, respectively. Blood samples were taken at 20-min intervals via a left jugular vein catheter. Metabolite and hormone concentrations during NH4Cl and POST periods were compared to PRE values using the Student's t-test procedure. Plasma NH3 was elevated rapidly (P less than .001) and peaked at 503 micrograms/dl 220 min into NH4Cl infusion. Plasma urea-N and glucose increased (P less than .001) 39 and 12%, respectively, during NH4Cl infusion and remained elevated 180 min POST. Whole blood L-lactate concentrations peaked (P less than .05) at 18% above PRE between 160 and 240 min into the NH4Cl infusion and gradually returned to PRE values, whereas pyruvate levels were not altered (P greater than .10). Plasma nonesterified fatty acids peaked (P less than .001) at 94% above PRE levels 40 min into NH4Cl infusion, thereafter declining to PRE concentrations. Whole blood acetoacetate and beta-hydroxybutyrate concentrations were not altered (P greater than .10) by NH4Cl administration. Plasma insulin concentration decreased (P less than .05) 26 to 46% during NH4Cl infusion and increased (P less than .05) 89 to 122% during POST. Plasma glucagon levels were not altered by NH4Cl infusion, so molar insulin:glucagon ratio changes resembled those of insulin. Plasma epinephrine, norepinephrine and dopamine did not vary (P greater than .10) with treatment. These results support the hypothesis that the hyperglycemia observed during hyperammonemia may result from an under-utilization of glucose by insulin-sensitive tissues.

Six hours post-hatch, large white turkey poults were inoculated intranasally with 5 x 10(7) cells of the W isolate of Bordetella avium. Three hours after inoculation and subsequently on days 7, 10, 14, 21, and 28 postinoculation, poults from infected and control groups were killed by cervical dislocation. Thymus, spleen, and bursa of Fabricius were removed, weighed, and frozen until assayed for norepinephrine (NE), dopamine (DA), and serotonin (5HT). B. avium infection caused a reduced concentration of NE, DA, and 5HT in the spleen, thymus, and bursa of Fabricius. The reduced concentrations of these monoamines in lymphoid tissues of diseased poults may be a normal response during the course of a disease or during the mounting of an immune response.