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At least 613 records · Page 34Linked to original sources
PubMed1992

The effect of triacylglycerol chain length on food intake in domestic fowl.

Triacylglycerols of varying chain lengths were tested for their effects on food intake in fasted Single-Comb White Leghorn cockerels 9-12 weeks of age. Tributyrin, tricaprylin, triolein, or saline were intubated intragastrically or infused intrahepatically. All triacylglycerol administrations were in 10 ml volumes with 10 kcal being infused intrahepatically and 10 or 20 kcal being infused intragastrically. When administered intragastrically, the short-chained triacylglycerol tributyrin decreased food intake at most times tested; the medium chain-length tricaprylin and the long chain-length triolein affected food intake sporadically. When infused into the liver, tributyrin and tricaprylin decreased food intake at most times tested, whereas triolein decreased food intake at 60 and 180 minutes only. Satiating effectiveness was related to triacylglycerol chain length when intubated, which may reflect rate of absorption from the gut; however, hepatic satiety receptors were also differentially sensitive to triacylglycerol chain length indicating that more than rate of assimilation from the gut must be considered.

Animals↗
PubMed1991

Red cell size and various lung arterial measurements in different strains of domestic fowl.

Red cell size and various lung arterial measurements were examined in different strains of young commercial broiler and layer fowls. The broilers were: Marshall, Cobb, Ross 'selected', Ross 'relaxed' and the layers were: Isa Brown, Ross Brown and Hisex Brown. The Ross relaxed bird had a significantly larger red cell than any other strain. Overall, broilers had larger red cells than layers. The internal elastic lamina, a measure of arterial size, was small in the Ross relaxed bird (138 microns) and was at its maximum (163 microns) in the selected Ross strain. The medial area (muscle coat) was least in the Ross relaxed bird (984 microns2) and greatest in the Cobb strain (1516 microns2). In some strains there was a slight correlation among birds between red cell and arterial size but not with the medial area. The results appeared to indicate that red cell size may not be the only important correlating factor in the aetiology of pulmonary hypertension in fowls.

Animals↗
PubMed1978

A study of the effect of SO2 on pacing and intrapulmonary chemoreceptor discharge in the domestic fowl.

Kunz and Miller )1974) described a phenomenon called pacing in which FCO2 oscillations forced in the lungs of unanesthetized unidirectionally ventilated chickens cause one ventilatory movement per ECO2 oscillation. In the present study SO2 (0.08--0.32 vol%) added to the ventilating gas stream caused a loss of pacing in 11 of 12 birds. In 7 of the 11 birds in which SO2 was effective, pacing returned 3.2--7.0 min after removal of SO2. Intravenous infusion of a similar quantity of SO2 (dissolved in saline) did not block pacing. In a second series of experiments chickens were again unidirectionally ventilated and single nerve fiber recording was used to investigate the effect of SO2 on individual intrapulmonary chemoreceptors (IPC). Of necessity, this work was done on birds which were anesthetized and paralyzed. Discharge was abolished in 10 of 12 IPC by doses of SO2 similar to those which blocked pacing. In 6 of the 10 fibers in which SO2 was effective, discharge resumed after a mean period of quiescence lasting 7 min. It is concluded that pacing is mediated by intrapulmonary rather than systemic chemoreceptors.

Animals↗
PubMed1983

Effects of PCO2 on respiratory pattern during thermal and exercise hyperventilation in domestic fowl.

The relationship between respiratory pattern and arterial PCO2 was investigated during hyperventilation induced by graded exercise and hyperthermia. Treadmill exercise was performed both in isothermic and hyperthermic conditions. Isothermic exercise was induced by spraying the birds with water before exercise at environmental temperatures of 18 +/- 2 degrees C. Hyperthermic exercise was performed in unsprayed birds at temperatures of 18 +/- 2 degrees C and 30 +/- 2 degrees C. During isothermic exercise there was no significant change in arterial PCO2 at moderate work loads and only a small drop in PCO2 at the heaviest work loads; ventilation was increased by coupled increases in tidal volume and respiratory frequency. During exercise in unsprayed birds rectal temperature rose progressively and arterial PCO2 fell progressively with work load. At each work load ventilation was higher and breathing was more rapid and shallow than during isothermic exercise. These effects were more pronounced during exercise at 30 +/- 2 degrees C than at 18 +/- 2 degrees C. When normal PCO2 was maintained during hyperthermic exercise, as a result of the administration of CO2-enriched air, polypnea was suppressed and the tidal volume-respiratory frequency relationship became identical to that observed during graded isothermic exercise. Maintenance of normal PCO2 in resting birds subjected to a gradual increase in environmental temperature also resulted in changes in respiratory pattern identical to those obtained during eucapnic exercise. It is concluded that, provided arterial PCO2 is held constant, the pattern of breathing is the same for hyperventilation induced by exercise or by body temperature increases.

Animals↗
PubMed1980

Tonic immobility in domestic fowl: anticataleptic effects of quipazine.

Quipazine, a putative serotonergic agonist, produced marked decreases in tonic immobility (TI) duration in doses of 5--25 mg/kg. Quipazine-treated animals required more elicitation attempts before displaying TI. Quipazine also blocked the haloperidol enhancement of tonic immobility. In a third experiment, quipazine produced stereotyped responses in chickens which yielded increases in activity on a stabilimeter platform. The results are discussed in terms of catalepsy and serotonerigic and dopaminergic mechanisms.

Animals↗
PubMed1980

Biphasic effects of serotonin on tonic immobility in domestic fowl.

In two experiments, groups of 2 1/2 to 3 week old chickens were injected intravenously with various dosages of serotonin and tested for tonic immobility. Relatively low doses of serotonin produced significant increases in the duration of immobility, while high doses only produced slight decreases in duration. Serotonin also reduced the activity levels of chickens before testing for immobility and made the response easier to induce, but there were no apparent differences due to dosage for either of these behaviors. The effects by serotonin on the immobility response and activity level were found to persist for over two hours with little decrease in their potency. The data in this study are used to explain the contradictory effects produced by serotonins on immobility during past research and are discussed in terms of the importance of differential responding by prey during predatory encounters.

Animals↗
PubMed1981

Differential effects of alpha-adrenergic antagonists on tonic immobility in domestic fowl.

Groups of young chickens were injected with various dosages of several alpha-adrenergic antagonists and tested for the effects of these drugs on tonic immobility. Yohimbine, a very potent alpha2 antagonist, produced a significant decrease in the duration of tonic immobility at doses of 1 mg/kg, while prazosin, a potent alpha1 antagonist, had no apparent effect on immobility duration. Phentolamine, a on-specific alpha antagonist, produced a significant decrease in the duration of immobility at doses of 0.1 mg/kg, but had no effect at higher or lower doses. These results support the involvement of the alpha-adrenergic system with the duration of the tonic immobility reflex, but at the same time they also suggest that alpha2 receptors are more closely involved with the immobility response than alpha1 receptors. However, none of these drugs had any apparent effect on the initial susceptibility of subjects to the immobility reflex, as measured by the number of inductions required to produce tonic immobility.

Adrenergic alpha-Antagonists↗
PubMed1981

Tonic immobility in domestic fowl: possible interaction of serotonergic and dopaminergic mechanisms.

Treatment with the dopamine (DA) receptor blocker, haloperidol, enhanced tonic immobility (TI) duration. Fenfluramine, a receptor agonist for serotonin (5-HT), reversed this effect. Tryptophan produced long TI reactions, and is believed to do so due to impaired synaptic transmission of 5-HT following its direct inhibitory effects on 5-HT neurons. DA receptor stimulation by apomorphine prevented the tryptophan potentiation of tonic immobility. The results suggest that serotonergic and dopaminergic systems may interact with respect to tonic immobility.

Animals↗