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Biomedical subjects

D M Denbow

Publications and source records attributed to D M Denbow.

At least 109 records · Page 6Linked to original sources
PubMed1985

Food and water intake of broiler chicks as affected by intracerebroventricular injections of cholinomimetics.

The effects of intracerebroventricular (ICV) injections of the cholinomimetics, acetylcholine, methacholine, and carbachol on food and water intake in free-feeding broiler chicks were investigated. At 4 weeks of age, a 23-gauge, thin-walled stainless steel guide cannula was implanted stereotaxically into the right lateral ventricle of each bird. Following a minimum of 3 days to recover, the birds were injected with the various drugs. Acetylcholine and methacholine had no significant effect on food intake whereas carbachol significantly decreased food intake. Methacholine significantly increased water intake while acetylcholine and carbachol had no significant effect. These results suggest that cholinergic pathways within the central nervous system may be involved in the control of food and water intake in the domestic fowl.

Acetylcholine↗
PubMed1985

Food and water intake response of turkeys to intracerebroventricular injections of angiotensin II.

The effects of intracerebroventricular (ICV) injections of angiotensin II on food and water intake were studied in adult Medium White turkey hens. Food intake was not significantly affected by ICV injections of angiotensin II. The ICV injection of 50, 100, and 200 ng of angiotensin II significantly increased water intake in a dose-dependent manner. The dipsogenic effect of angiotensin II was significantly attenuated by Saralasin, an angiotensin blocker. These results suggest that angiotensin II functions in neural pathways within the central nervous system to control water intake, but not food intake, in turkeys.

Angiotensin II↗
PubMed1984

Changes in Ca2+ ion activity within unrestrained rat's hippocampus perfused with alcohol or acetaldehyde.

In the freely moving rat, the kinetics of Ca2+ ion activity were determined at circumscribed sites in the hippocampus, which was perfused with ethanol, tertiary-butyl alcohol or acetaldehyde. Initially, a region in CA1 or other cell field of the dorsal hippocampus was prelabelled by microinjection of 45Ca2+ through a permanently implanted guide tube. Then the tip of a concentric push-pull cannula assembly was lowered through the guide tube to the labelled site, and an isotonic artificial cerebrospinal fluid was repeatedly perfused at a rate of 25 microliter/min. Each perfusion was timed for 5.0 min with a 5.0 min interval between each. Once the washout curve of 45Ca2+ activity had begun to approach its asymptote, ordinarily in the midpoint of a series of perfusions, an isotonic solution of ethanol (188-942 mM), tertiary-butyl alcohol (12-580 mM) or acetaldehyde (10-98 mM) was added to the fourth perfusate. Thereafter, the hippocampal site was again perfused with the normal cerebrospinal fluid for the remainder of the experiment. Although the lowest concentration of ethanol exerted no effect on 45Ca2+ ion activity, an intermediate concentration caused mixed effects in either enhancing or suppressing the efflux into the perfusate of this cation. The highest concentration of ethanol produced in most experiments an initial suppression in Ca2+ ion efflux which was followed frequently by an elevation in the release of 45Ca2+. Similar changes in Ca2+ ion activity were produced by tertiary-butyl alcohol, but the magnitude of its effect was generally less than that of ethanol, suggesting that its effect on brain tissue differs from that of ethanol. Acetaldehyde evoked an intense and concentration-dependent enhancement of Ca2+ ion efflux from the perfused tissue at all of the sites in the hippocampus examined. These results suggest that in the unrestrained rat ethanol could unbind Ca2+ ions from hippocampal membranes or retard their uptake into cells of the hippocampus. The dual excitatory and inhibitory effect of ethanol on Ca2+ ion activity corresponds to the electrophysiological effects of this alcohol and could alter neurotransmitter release from neurons in this subcortical structure. The mechanism of action of acetaldehyde is envisaged to be due to its affinity to membrane sulfhydryl groups which alters protein conformation and thus interferes with both Ca2+ channels and Ca2+ binding properties.

Acetaldehyde↗
PubMed1984

Behavior and growth parameters of large white turkeys as affected by floor space and beak trimming. 1. Males.

The effects of floor space and beak trimming on behavior and growth of Large White male turkeys were investigated Floor space allowances were 6.5, 9.3, and 12.1 dm2/bird at 0 to 8 weeks; 11.7, 16.7, and 21.8 dm3/bird at 8 to 12 weeks; and 28, 35, and 42 dm3/bird at 12 to 20 weeks. Floor space was adjusted by changing the pen size while maintaining a constant number of birds per pen. Body weight, feed intake, feed efficiency, feather score, live market quality, and mortality were measured. In addition, agonistic behavior including "threat avoids", "peck avoids", "threat chases", "peck chases" and "fights", and nonagonistic behavior including feather "pecks" and "pecks and pulls" were determined at 12 and 20 weeks of age. Floor space had no significant effect on any parameter measured through 8 weeks. At 12 weeks, feed efficiency and body weight were significantly decreased with decreasing floor space. By 20 weeks, the body weight of the birds grown at the intermediate floor space allowance from 8 to 12 weeks was no longer significantly different from those grown at the highest floor space allowance; however, the birds grown at the highest density from 8 to 12 weeks remained significantly lighter at 20 weeks. Compensatory growth, if present, appeared limited. Beak trimming had no significant effect on body weight or feed efficiency. Food intake was significantly greater in the beak trimmed birds from 12 to 18, but there was no significant difference from 12 to 20 weeks. From 12 to 20 weeks, mortality was significantly less in beak-trimmed birds.(ABSTRACT TRUNCATED AT 250 WORDS)

Aggression↗
PubMed1984

Tyrosine and tryptophan influence on tonic immobility in the chicken.

The serotonergic and catecholaminergic systems have been shown to affect both tonic immobility and food intake in the domestic fowl. Tryptophan, the amino acid precursor of serotonin, has been demonstrated to influence tonic immobility and food intake when injected intraperitoneally. Tyrosine, amino acid precursor of the catecholamines, is also known to affect food intake when administered orally. In two experiments, tryptophan and tyrosine were intubated intragastrically into male chickens at levels known to affect food intake, and their effect on tonic immobility was measured. Tryptophan and tyrosine delivered intragastrically had no effect on either duration or susceptibility of tonic immobility. These data suggest that changes in appetite observed as a result of orally administered tyrosine and tryptophan were not due to a general inhibition or stimulation of the central nervous system.

Animals↗
PubMed1984

Ultrastructural analyses of uterovaginal sperm storage glands in fertile and infertile turkey breeder hens.

The ultrastructure of the uterovaginal (UV) sperm storage glands of fertile turkey breeder hens was characterized. Sperm glands were also studied over the course of an entire egg-laying season to determine if changes in ultrastructure occurred with time. In addition, ultrastructural comparisons were made between glands from fertile and infertile hens. Protein synthesis by the sperm gland epithelial cells appeared to be limited. The rough endoplasmic reticulum was not well developed. Intracellular glycogen storage was also minimal. However, lipid stores within the epithelial cells were relatively elevated. The degree of development of the apical microvilli and the presence of baso-lateral plasma membrane folds suggested that a primary function of the glandular epithelium was absorption. The length of time that a hen had been producing eggs did not influence the ultrastructure of UV gland epithelial cells. The morphology of glands from hens collected immediately prior to the commencement of egg production was similar to that of glands taken from hens that had completed an entire season of egg production. Aside from the observation that very few spermatozoa were found in the UV sperm glands of infertile hens, no detectable ultrastructural differences were observed between glands from fertile and infertile hens. Furthermore, there was no ultrastructural evidence of a microbial infection, nor was there evidence of an immunological response at the level of the sperm glands in the infertile hens.

Animals↗
PubMed1983

Feeding, drinking and body temperature of Leghorn chicks: effects of ICV injections of biogenic amines.

The effects of dopamine (DA), norepinephrine (NE), epinephrine (E) and 5-hydroxytryptamine (5-HT) on food intake, water consumption and colonic body temperature (Tc) were investigated using Leghorn-type chicks. Food intake was not significantly affected by the intracerebroventricular injections of DA, NE or E. In contrast, 5-HT significantly decreased food intake in both sated and fasted chicks. Tc was significantly decreased by NE and E whereas DA and 5-HT prevented the decline seen in controls. Water consumption was not significantly affected by DA, NE or E; however, 5-HT increased water consumption of sated chicks and decreased water consumption in fasted ones. The feeding response of Leghorn chicks following ICV injection of these biogenic amines differs from that previously observed in the broiler-type chicks. This disparate response is discussed in relation to the different growth rates of the two types of birds.

Animals↗
PubMed1983

Food intake and temperature response to injections of catecholamines into the lateral ventricle of the turkey brain.

The effects of dopamine, norepinephrine, and epinephrine on food intake, water intake, and colonic body temperature (Tc) were investigated in adult Medium White turkey hens. Solutions containing dopamine, L-norepinephrine, or L-epinephrine were prepared in concentrations of 0, 33, and 67 micrograms/10 microliters in artificial cerebrospinal fluid and injected into the lateral cerebral ventricles. Dopamine, norepinephrine, and epinephrine significantly decreased Tc. Food intake was significantly decreased by norepinephrine and epinephrine whereas dopamine had no effect. These results suggest that brain catecholamines are involved in the neural control of food intake and body temperature of turkeys.

Animals↗
PubMed1983

Influence of age on the temperature response of chickens to Escherichia coli and Salmonella typhimurium endotoxins.

An experiment was conducted to investigate the influence of age on the temperature responses of chickens given bacterial endotoxins. Broiler cockerels 1 to 8 weeks of age received a single intravenous injection of either distilled water (controls), Escherichia coli 0127:B8, or Salmonella typhimurium endotoxins. Rectal temperatures were recorded before and after injection, the birds were placed in an environmental chamber preheated to 33 C, and thereafter rectal temperatures were taken every 30 min for 180 min. In one-week-old chicks, a significant temperature loss was found 30 min after E. coli treatment, and this was followed 60 min later by a significant increase in rectal temperature. The E. coli and S. typhimurium treatments caused a .4 and .5 C increase, respectively, in 2-week-old chicks. Birds aged 3 to 8 weeks developed fevers with maximum changes in rectal temperatures ranging from .3 to 1.6 C. Seven- and eight-week-old chicks developed the highest and most persistent fevers. The febrile response of 5 to 8 week-old chicks was of longer duration than that of younger chicks. It was concluded that the febrile response following endotoxin administration is affected by age.

Age Factors↗
PubMed1982

Unique contribution of catecholamine receptors in the brain of the cat underlying feeding.

After a Collison cannula was implanted bilaterally in the cat for intracerebroventricular (ICV) injection, individual patterns of food intake were determined. A mixture of dry and canned cat food was provided to the animal every morning at the same time for 1.0 hr. Once intakes had stabilized, either norepinephrine (NE) or an adrenoreceptor blocking agent was infused in one lateral ventricle by gravity flow over an interval of 30-60 sec. NE given ICV in a dose of 25-75 micrograms 15 min before the period of feeding enhanced both the amount of food consumed by the cat and the duration of its feeding for up to 1.0 hr. When phentolamine in a dose of 25-100 micrograms was infused 15 min prior to the feeding interval, the cat's intake of food was attenuated in a dose-dependent manner, again in terms of both the quantity consumed and the interval of eating. Propranolol was essentially without effect on food intake. In the fully satiated cat, NE infused ICV 15-45 min following the termination of its morning feeding episode tended to augment food intake at the highest 100 micrograms dose, but the effect was not significant. The dose-dependent hypothermia typically observed after NE is given ICV to the cat was found to be entirely independent of the feeding response. Overall, these findings show that noradrenergic pathways in the cat's feeding system apparently bias or otherwise modulate the amount of food consumed. As in other species, the feeding mechanism appears to be mediated through alpha-adrenergic receptors presumed to be in the diencephalon of the cat.

Animals↗
PubMed1982

Feeding and drinking response of young chicks to injections of serotonin into the lateral ventricle of the brain.

The effects of serotonin [5-hydroxytryptamine (5-HT)] on food intake and water consumption were investigated in young broiler chicks. Artificial cerebrospinal fluid containing either 0, 33, 67, or 100 microgram of 5-HT/10 microliter was injected into the lateral ventricle of either 24-hr fasted or fully fed chicks maintained in a thermoneutral environment with continuous lighting. Neither cannulation per se nor injection of 10 microliter of artificial cerebrospinal fluid had an effect on food intake or water consumption. Furthermore, food intake was not affected by 5-HT in fasted chicks. In fully fed chicks, however, food intake was significantly decreased by 67 and 100 microgram of 5-HT. Water consumption was affected by 5-HT injection in fully fed chicks. Results with fasted chicks remain equivocal. Data suggest that 5-HT may be involved in the neurohumoral control of food intake.

Animals↗
PubMed1982

Peripherally administered cations do not modify febrile responses induced in chickens by Escherichia coli.

Two experiments were conducted to investigate the effects on intramuscular injections of Escherichia coli strains B and W on rectal temperature in broiler chicks and to investigate the effects of various cations on the temperature response. In Experiment 1, 4 birds were randomly assigned to each of three treatments. Control birds received a dextrose (50 mg/100 ml) solution and treated birds received a suspension of either E. coli B or E. coli W lyophilized cells (100 mg/kg) in a volume of 2 ml/kg. Rectal temperatures were recorded before injection and thereafter every 4 hr for a period of 24 hr. In Experiment 2, 10 birds were assigned randomly to each of two treatments. Birds received intramuscularly 2 ml/kg body weight injections of either dextrose (50 mg/100 ml) solution or a suspension of E. coli B lyophilized cells (100 mg/kg) in a volume of 2 ml/kg. At 16 hr after injection, rectal temperatures were recorded and birds were divided into the following treatments with 5 birds per group. Birds previously receiving dextrose (50 mg/100 ml) were given intramuscular injections (2 ml/kg body weight) of demineralized distilled water or a 2 ml/kg injection of .5 M solution of either Na+, K+, Ca+2, or Mg+2 made from their chloride salts. Birds previously receiving E. coli B were given intramuscular injections (2 ml/kg body weight) of demineralized distilled water or an injection of a .5 M solution of either Na+, K+, Ca+2, or Mg+2. Five birds served as uninjected controls. Rectal temperatures were taken every 30 min for 90 min thereafter. In Experiment 1, intramuscular injections of E. coli B and E. coli W resulted in an initial fall in rectal temperatures of chickens followed by a rise after 4 hr that peaked at 16 hr postinjection and at 24 hr remained significantly above preinjection values. The injection of the cations Na+, K+, Ca+2, or Mg+2 in Experiment 2 did not significantly affect the febrile response produced by E. coli B.

Animals↗
PubMed1982

Food and water intake following injection of glucose into the lateral ventricle of the brain of broiler type chicks.

The effects of glucose and 2-deoxy-D-glucose (2-DG) on food intake and water consumption were investigated in broiler chicks. Artificial cerebrospinal fluid (aCSF) containing either glucose or the glucose antimetabolite 2-DG was injected into the lateral brain ventricles of fasted and satiated chicks. The satiated chicks received 10 microliters of CSF containing either 5 or 10% 2-DG, whereas those fasted for 24 hr received CSF with 10, 20, or 30% glucose (dextrose) in 10 microliters volumes. Chicks were maintained in a thermoneutral environment with continuous lighting. Intraventricular injections of 5 or 10% 2-DG had no significant effect on food intake or water consumption in the fully-fed chicks. In the 24-hr fasted chicks, 10% glucose had no effect on food or water intake. The decrease in food intake observed following the injection of 20 and 30% glucose appeared to be an osmotic effect. Based on results obtained, it was suggested that selection for increased growth rate, such as in broilers, may have resulted in a decrease in glucoreceptor sensitivity. Such a decrease in sensitivity could lead to an increased food intake as occurs in broilers.

Animals↗
PubMed1981

Gaseous metabolism of leghorns and broilers during early growth: existence energy rate.

Existence energy rate (EER) was measured on male Ross x Arbor Acre broilers and DeKalb 231 x Cornell White Leghorns from day of hatch to 8 weeks of age. The EER was measured in an open circuit respirometer with feed and water available ad libitum. The log of heat production (kilocalories per bird per day) was plotted against the log for body weight (kilograms) for each type bird. Data from broilers and Leghorns were then compared using analysis of covariance. The equations best describing EER for Ross x Arbor Acre broilers and DeKalb 231 x Cornell White Leghorns were Y = 148W.77 and Y = 110W.74, respectively, where Y equals kcal/bird-day and W equals body weight (kg). There was no significant difference in slope (.77 compared to .74) between the two types of poultry; however, broilers had a significantly higher EER than Leghorns (147 compared to 110) when analyzed at equal body weights. Apparently the greater food intake and activity associated with feeding effected the marked increase in heat production by broilers.

Animals↗
PubMed1981

Rectal temperature and blood chemical responses of young chickens given E. coli endotoxin.

Two experiments were conducted to investigate the effect of intravenous injections of bacterial endotoxin in broiler chicks. In both experiments 5-weeks-old chicks were given a single intravenous injection of either distilled water (control) or 1 mg/kg Escherichia coli endotoxin (serotype 0.127:B8) in a volume of 1 mg/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 plasma magnesium, sodium, or inorganic phosphorus were observed in endotoxin-treated chicks.

Animals↗