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At least 253 records · Page 14Linked to original sources

ICV administration of anti-NPY antisense oligonucleotide: effects on feeding behavior, body weight, peptide content and peptide release.

Neuropeptide-Y (NPY) is a potent stimulator of feeding, and chronic administration of the peptide has been shown to increase body weight. This study determined the chronic effects of repeated daily injections of an antisense phosphorothioate oligonucleotide complementary to the rat mRNA for NPY (aNPY) on food intake, feeding behavior and body weight change in rats. Five micrograms of the aNPY oligonucleotide in ten microliters of vehicle or a missense control oligonucleotide were administered intracerebroventricularly (ICV) for seven consecutive days. Cumulative food intake, meal size and meal duration were significantly lowered in aNPY-treated animals. Body weight change of aNPY-injected animals was significantly lower than controls, and the effect was reversed after treatments ceased. A two-bottle taste aversion paradigm was employed to determine the behavioral specificity of the anorectic effect, and the phosphorothioate oligonucleotide was found not to be aversive at the dosage used. Following an additional five day injection period, animals were killed and paraventricular nuclei (PVN) were dissected. In vitro release and tissue content of NPY from this brain area were evaluated by heterologous radioimmunoassay. Content of NPY was unchanged in this brain area. Paradoxically, in vitro release of NPY was increased in aNPY-treated animals.

Animals↗

Feeding behavior of different species of Chagas' disease vectors stimulated with blood sources at different temperatures.

1. The feeding behavior of six triatomid species toward latex condoms filled with blood at 26 +/- 1 and 36 +/- 1 degrees C was observed for 4 h. 2. The species studied were Triatoma infestans, Triatoma brasiliensis, Triatoma vitticeps, Triatoma pseudomaculata, Rhodnius prolixus and Panstrongylus megistus, and 34 to 348 insects were studied in each group (average, 190). All the life stages of each species were used. 3. Although most insects (80%, average for 6 species) preferred the warmer blood, 54% of the individuals of all species fed on blood kept at 26 degrees C. For Triatoma pseudomaculata, a higher proportion of insects fed on blood at 26 degrees C (92%) than on blood at 36 degrees C (65%). 4. These results suggest that bait containing insecticides which are effective through the digestive tract may be useful in the control of these vectors even at room temperature.

Animals↗

Coping with rising food costs in a closed economy: feeding behavior and nocturnal hypothermia in pigeons.

The pigeon's response to increasing fixed-ratio schedules in a 24-hr closed economy is marked by changes in feeding behavior during the daily light phase and by changes in body temperature during the dark phase. The time course of these responses to increasing behavioral cost of obtaining food is very different. Feeding is most affected immediately, within the first day of exposure to moderate fixed ratios. The number of times the pigeons produce the food hopper each day decreases, and the rate at which they eat from the food hopper (grams per minute) when it is available increases, as the fixed ratio is raised. Body temperature is affected later, falling to progressively lower resting levels during the dark phase as body weight drops at the higher fixed ratios when food intake is reduced. The changes in feeding and in body temperature that occur as the fixed-ratio schedule increases seem to reduce daily energy expenditures, within the constraints imposed by the experiment. The ascending and descending limbs of the bitonic function obtained when total daily operant responding is plotted as a function of fixed-ratio schedule in the closed economy is possibly related to the occurrence of thermoregulatory strategies for energy conservation. The energetic analysis of performances in the closed economy requires consideration of a variety of energetic strategies available to the species being studied.

Animals↗

Targeted disruption of Huntingtin-associated protein-1 (Hap1) results in postnatal death due to depressed feeding behavior.

HAP-1 is a huntingtin-associated protein that is enriched in the brain. To gain insight into the normal physiological role of HAP-1, mice were generated with homozygous disruption at the Hap1 locus. Loss of HAP-1 expression did not alter the gross brain expression levels of its interacting partners, huntingtin and p150glued. Newborn Hap1(-/-) animals are observed at the expected Mendelian frequency suggesting a non-essential role of HAP-1 during embryogenesis. Postnatally, Hap1(-/-) pups show decreased feeding behavior that ultimately leads to malnutrition, dehydration and premature death. Seventy percent of Hap1(-/-) pups fail to survive past the second postnatal day (P2) and 100% of Hap1(-/-) pups fail to survive past P9. From P2 until death, Hap1(-/-) pups show markedly decreased amounts of ingested milk. Hap1(-/-) pups that survive to P8 show signs of starvation including greatly decreased serum leptin levels, decreased brain weight and atrophy of the brain cortical mantel. HAP-1 is particularly enriched in the hypothalamus, which is well documented to regulate feeding behavior. Our results demonstrate that HAP-1 plays an essential role in regulating postnatal feeding.

Animal Nutritional Physiological Phenomena↗

A system for the automated recording of feeding behavior and body weight.

A method that uses passive integrated transponder (PIT) tags for the continuous recording of feeding behavior and body weight from multiple individual animals is described. We have used this method in the field and in semi-natural captive conditions with black-capped chickadees (Poecile atricapillus) to determine daily and seasonal patterns in body weight and to estimate the proportions of food cached and consumed.

Animals↗

Effect of yolk sac removal at hatch on growth and feeding behavior in lines of chickens differing in body weight.

Influence of residual yolk on growth, feeding behavior, and development of certain internal organs during the first week after hatch were measured in lines of chickens that had undergone long-term selection for high (HW) or low (LW) 56-day body weight. At hatch chicks were assigned to one of the following treatments: removal of residual yolk (Y), sham operated (S), or no surgery (I). Body weight gains of HW chicks began on day 1 while LW chicks did not begin to gain weight until several days after hatch. Food intake increased linearly in both lines, but at a higher rate for HW than LW chicks. Seven days after hatch, relative to body weight, shanks were longer and pancreases and small intestines heavier for HW than LW chicks. Among treatments, body weight gains were greater for I and S than for Y chicks in the HW line, but not the LW line, demonstrating a differential response by fast and slow growing chicks to removal of the yolk sac. Feed intake differed on day 3, with Y chicks eating less than S chicks; I chicks were intermediate. Results indicate that presence of residual yolk sac during the first three days after hatch are critical to growth and development of chicks.

Animals↗

Evoked potentials as indicator of possible involvement of ventromedial hypothalamus and lateral nucleus of the amygdala in the formation of feeding behavior.

Electrical stimulation of the ventromedial hypothalamus in cats leads to the appearance of an additional component in the structure of evoked potentials of the amygdala lateral nucleus; this component disappears after discontinuation of food reinforcement (suppression of the conditioned reflex). It was concluded that the lateral nucleus of the amygdala and ventrolateral hypothalamus, the structures belonging to the system of defense behavior, can change their congenital characteristics depending on the situation, when involved in the feeding behavior system.

Amygdala↗

Internal stimuli enhance feeding behavior in the mollusc Aplysia.

The hypothesis that subsatiating levels of internal food stimuli can arouse and potentiate feeding behavior was examined in the mollusc Aplysia californica. Animals were fed a small quantity of seaweed and their latencies to show biting responses were determined after food arousal was permitted to partially decay. Control animals were stimulated with food, but were not permitted to ingest it, or were fed nonnutritive glass-fiber filter paper. Compared to controls, animals that were fed showed significantly shorter latencies to respond when tested up to 80 min after previous exposure to food. These results indicate that internal stimuli can function like external stimuli to enhance responsiveness to food and suggest the hypothesis that satiation may be viewed as an interactive process involving the interplay of excitatory and inhibitory influences arising from the alimentary system.

Animals↗

Effect of feeding space on the inter-cow distance, aggression, and feeding behavior of free-stall housed lactating dairy cows.

The objectives of this study were to determine whether doubling the amount of feeding space from 0.5 to 1.0 m per cow leads to increased spacing between cows at the feeder, fewer aggressive social interactions among cows, and ultimately increased feeding activity. Twenty-four lactating Holstein cows were provided with 0.5 and 1.0 m of feeding space per cow in a 2 x 2 crossover design replicated over time. Time-lapse video was used to quantify the inter-cow distance and incidence of aggressive displacements at the feed alley. An electronic feed alley monitoring system was used to monitor the feeding behavior of the cows. When animals had access to 1.0 m per cow, there was at least 60% more space between animals and 57% fewer aggressive interactions while feeding than with access to 0.5 m of feeding space. These changes in spacing and aggressive behavior in turn allowed cows to increase feeding activity throughout the day, especially during the 90 min after providing fresh feed (an increase of 24%). This increase in feeding activity was particularly evident for subordinate cows. These results indicate that increasing space allowance at the feeder increases feeding activity and reduces competition among lactating dairy cows.

Aggression↗

Feeding behavior and venom toxicity of coral snake Micrurus nigrocinctus (Serpentes: Elapidae) on its natural prey in captivity.

The feeding behavior and venom toxicity of the coral snake Micrurus nigrocinctus (Serpentes: Elapidae) on its natural prey in captivity were investigated. Coral snakes searched for their prey (the colubrid snake Geophis godmani) in the cages. Once their preys were located, coral snakes stroke them with a rapid forward movement, biting predominantly in the anterior region of the body. In order to assess the role of venom in prey restraint and ingestion, a group of coral snakes was 'milked' in order to drastically reduce the venom content in their glands. Significant differences were observed between snakes with venom, i.e., 'nonmilked' snakes, and 'milked' snakes regarding their behavior after the bite. The former remained hold to the prey until paralysis was achieved, whereas the latter, in the absence of paralysis, moved their head towards the head of the prey and bit the skull to achieve prey immobilization by mechanical means. There were no significant differences in the time of ingestion between these two groups of coral snakes. Susceptibility to the lethal effect of coral snake venom greatly differed in four colubrid species; G. godmani showed the highest susceptibility, followed by Geophis brachycephalus, whereas Ninia psephota and Ninia maculata were highly resistant to this venom. In addition, the blood serum of N. maculata, but not that of G. brachycephalus, prolonged the time of death of mice injected with 2 LD(50)s of M. nigrocinctus venom, when venom and blood serum were incubated before testing. Subcutaneous injection of coral snake venom in G. godmani induced neurotoxicity and myotoxicity, without causing hemorrhage and without affecting heart and lungs. It is concluded that (a) M. nigrocinctus venom plays a role in prey immobilization, (b) venom induces neurotoxic and myotoxic effects in colubrid snakes which comprise part of their natural prey, and (c) some colubrid snakes of the genus Ninia present a conspicuous resistance to the toxic action of M. nigrocinctus venom.

Animals↗

Effect of hypothalamic administration of growth hormone-releasing factor (GRF) on feeding behavior in rats.

To examine the role and working site of growth hormone-releasing factor (GRF) in feeding behavior, we first tested the effect of the intracerebroventricular (i.c.v.) injection of GRF on food intake after 24 h of food deprivation. Cumulative food intake was measured 1, 3 and 6 h after injection. A lower dose of GRF stimulated food intake in a dose dependent manner (3 h; GRF 100 pmol 8.64 +/- 1.06 g vs saline 5.50 +/- 0.60 g, P less than 0.05), while a higher dose (1 nmol, 500 pmol) suppressed food intake (3 h; GRF 1 nmol 2.65 +/- 0.70 g vs saline 5.50 +/- 0.60 g, P less than 0.01). Second, the effect of i.c.v. injection of 100 pmol of GRF on peripheral metabolites was examined. The subsequent levels of plasma insulin, glucagon, glucose and non-esterified fatty acid showed no significant difference from those of saline administration. Third, the effect of microinjection of GRF (5 pmol) into several hypothalamic areas on food intake was examined. Injection into the ventromedial hypothalamic nucleus (VMN) stimulated food intake (3 h; GRF 5 pmol 10.32 +/- 1.04 g vs saline 6.92 +/- 0.32 g, P less than 0.05), but no significant effect was observed following injection either into the lateral hypothalamic area (LHA), paraventricular nucleus (PVN) or medial preoptic area (MPOA). Finally, we tested the stimulatory effect of GRF on food intake in bilateral VMN lesioned rats. I.c.v. injection in these animals had no more significant effect on food intake than did saline injection in VMN lesioned rats (3 h; GRF 100 pmol 6.27 +/- 0.87 g vs saline 5.34 +/- 0.44 g).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Feeding behavior of Lutzomyia pseudolongipalpis (Diptera: Psychodidae), a putative vector of visceral leishmaniasis in Venezuela.

Lutzomyia pseudolongipalpis Arrivillaga & Feliciangeli is the first new sand fly species in the L. longipalpis species complex that has been formally described since it was separated by genetic as well as by morphological characters. It is the putative vector of the American visceral leishmaniasis in La Rinconada, Curarigua, a restricted focus in central western Venezuela. We investigated the feeding behavior of this species. The blood meals from 210 of 429 (48.9%) engorged females caught by CDC light traps were identified by a dot enzyme-linked immuno-absorbent assay using antisera against humans and common domestic animals. We propose a new index, the host selectivity index, which is the number of sand flies fed on a given host relative to the available biomass of that host, as an indicator of the feeding behavior of this phlebotomine sand fly. The host selectivity index is compared with the forage ratio, which is the percentage of sand flies fed on a given host by the percentage which that host represented in the total census of available animals and humans. The most attractive animal for L. pseudolongipalpis in Curarigua was the dog, whereas humans were shown to be relatively unattractive. However, not only selectivity or biomass, but also the accessibility to this host may have influenced these results. The low population density of dogs and the low accessibility of L. pseudolongipalpis to humans in relation to domestic animals might help to explain the sporadic transmission of visceral leishmaniasis in this focus.

Animals↗

Feeding behavior and entrainment limits in the circadian system of the rat.

The entrainment limits of the circadian rhythms of feeding activity were studied in Wistar rats exposed to gradually increasing and decreasing or to static light-dark cycles. In the former, the entrainment limits of feeding behavior were 22 h 10 min and 26 h 40 min. In the latter, the upper limit was higher, because rats under zeitgeber period (t) length = 27 h (t27) and t28 met the criteria of entrainment. The lower limit, on the other hand, was not modified because none of the t22 animals showed entrained rhythms and one-half of the t23 rats exhibited two components in their circadian feeding rhythms, one with a period of 23 h and the other free running. This 23-h component reflected not only the masking effect of light-dark cycles but also seemed a true light-entrained component. In well-synchronized animals, food intake seemed to depend more on the number of cycles that the animal experienced than on actual time lived; however, other feeding parameters, such as meal frequency and feeding duration, remained constant when expressed per 24 h, irrespective of the t cycle. These results concerning feeding duration, meal frequency, and food intake revealed that the homeostatic and circadian controls interacted to a degree that depended on the type of variable considered. In conclusion, the entrainment limits appeared much more imprecise than they were previously thought to be, because the circadian system can only be partially synchronized near its entrainment limits. The hypothesis that the rat's circadian system is composed of multiple oscillators with different intrinsic frequencies and varying capacities for light synchronization would explain the partial desynchronization observed near the entrainment limits.

Animals↗

Research on "feeding behavior": quantitative information vs. qualitative perceptions about where it is published.

To gain some understanding of where research on "feeding behavior" is published, a Medline search was conducted for the years 1980-1990 inclusive using the above key phrase to capture published articles coded in this way. Furthermore, an eight-item questionnaire was mailed to all 451 persons listed in the 1990 membership directory of the Society for the Study of Ingestive Behavior (SSIB) soliciting views on the top five journals publishing the greatest number, as well as the most "prestigious," articles in this field, along with demographic information about the respondents. After deleting journals that published agriculturally based research relating to insects or parasites, the Medline search generated 1,813 articles in the top 25 journals, the top 5 of which were Physiology and Behavior (462 articles), Pharmacology, Biochemistry and Behavior (211 articles), Brain Research (118 articles), American Journal of Physiology (106 articles) and Brain Research Bulletin (87 articles). This fact accorded well with weighted scores generated from perceptions of SSIB respondents (24.4% return rate), whose top 25 rankings correlated highly (r14 = +0.829, p < .001) with the Medline data. Although the top 5 number 1 choices of "prestige" journals by SSIB members did not match up well with the Medline list, weighted "prestige" scores correlated reasonably well with the Medline data (r15 = +0.766, p < .001), but a bit less so with SSIB perceptions of where greatest numbers of articles appeared (r12 = +0.588, p < .05). Discussion is presented about the validity of these data, their implications, and their potential utility in helping researchers decide where to publish work in this field.

Animals↗

Steroid saponins from fenugreek seeds: extraction, purification, and pharmacological investigation on feeding behavior and plasma cholesterol.

The seeds of fenugreek (Trigonella foenum graecum L.) are traditionally assumed to have restorative properties. We have recently shown that a fenugreek seed extract containing steroid saponins increased food consumption and induced hypocholesterolemia in rats. This study aims to investigate the specific role of purified steroid saponins in these properties. For this purpose, an original technique for extraction and purification of steroid saponins was carried out. Thereafter, the effects of these steroid saponins were investigated on feeding behavior and metabolic endocrine changes in normal and diabetic rats. All the steroid saponins (furostanol type) were extracted from the seeds and separated from all other constituents of the entire extract by using several purification procedures to give an extract containing at least 90% of steroid saponins. Pharmcological experiments were performed in vivo in normal and streptozotocin diabetic rats: steroid saponins were administered chronically mixed with food (12.5 mg/day per 300 g body weight). Our data show that the treatment with steroid saponins significantly increased food intake and the motivation to eat in normal rats, while modifying the circadian rhythm of feeding behavior; it also stabilized the food consumption in diabetic rats, which resulted in a progressive weight gain in these animals, in contrast to untreated diabetic controls. Both in normal and diabetic rats, steroid saponins decreased total plasma cholesterol without any change in triglycerides. In conclusion, the present work reports a clear methodology to obtain all the steroid saponins and demonstrates that these saponins enhance food consumption and motivation to eat, and reduce plasma cholesterol levels in rats.

Animals↗

Within-day feeding behavior of lactating dairy cows measured using a real-time control system.

The suitability of a statistical model for describing within-day feeding behavior, and potential relationships between model parameters and commonly measured experimental variables were examined. Forty multiparous, midlactation Holstein cows were fed using a real-time control system to record the date of each visit to a feeder, entrance time, exit time, and feed consumed over a 6-wk period. Daily feed consumption, number of visits, meal duration, and within-visit rate of food intake were then calculated. Two peaks in within-day rates of feed intake were indicated, suggesting that feeding activity was randomly distributed around each peak, that is, binormal. Parameters describing the distributions (means, standard deviations, and the percentage of total feeding activity associated with each peak) were estimated. An adjusted average of 91% of the variation in within-day feeding activity was explained by the binormal model. Relationships between model parameters and commonly measured experimental variables were also identified; behavioral traits were correlated with total feed intake. Feeding activity patterns in literature data were also amenable to reanalysis by the binormal model. Lactating cows consistently exhibited a distinct diurnal pattern in feeding activity; they were most active near sunrise and again near sunset (crepuscular). Effects of various management operations (e.g., feeding and milking times and frequencies, and lighting) on within-day feeding patterns remain to be established, although a statistical model for evaluating them is now available. The patterns may have important implications for scheduling management activities to maximize feed intake and production.

Animal Feed↗

Pharmacologically induced elements of the hunting and feeding behavior in the pteropod mollusk Clione limacina. I. Effects of GABA.

1. The pteropod mollusk Clione limacina is a predator, feeding on the small pteropod mollusk Limacina helicina. Injection of gamma-aminobutyric acid (GABA) into the hemocoel of the intact Clione evoked some essential elements of the hunting and feeding behavior, i.e., protracting the tentacles, opening the mouth, and triggering the rhythmic movements of the buccal mass. This pattern resembled that evoked by presentation of the prey: Clione grasped the Limacina by its tentacles, extracted the prey's body from the shell and then swallowed it. 2. In electrophysiological experiments, several targets of GABA action have been found: 1) direct application of GABA to isolated cerebral motor neurons projecting to the protractor muscles of tentacles resulted in their excitation; 2) GABA activated the feeding rhythm generator located in the buccal ganglia; 3) GABA exerted excitatory or inhibitory effects on the receptor cells of statocysts, the effects being mediated by the efferent input to these cells; 4) GABA suppressed the defense reaction, which is an inhibition of the locomotor activity and of tentacle motor neurons, arising in response to stimulation of the head afferents; and 5) GABA potentiated an excitatory action of the serotoninergic metacerebral cells on the feeding rhythm generator. 3. Effects of GABA on the tentacle motor neurons and the feeding rhythm generator are pharmacologically distinguishable. The action of GABA on the feeding rhythm generator was mimicked by baclofen (which activates the GABAB receptors in mammalian neurons) and was not sensitive to bicuculline (the GABAA receptor antagonist in mammals). On the other hand, bicuculline competitively inhibited the GABA-induced excitation of the tentacle motor neurons. 4. GABAergic neurons have been located in the cerebral, pedal, and buccal ganglia by means of immunohistochemical methods.

Animals↗