Food Preference Test Research Articles

Microstructural analysis of chlordiazepoxide's effects on food preference behavior in Roman high-, control- and low-avoidance rats

The effects of chlordiazepoxide (CDP) on feeding performance and on rearing activity were investigated using a food preference test in three Roman strains: Roman Low Avoidance (RLA), Roman Control Avoidance (RCA), and Roman High Avoidance (RHA). The aims of the study were to assess the responses of the three strains to a free choice of familiar and novel foods following a period of food deprivation, and to answer the important psychopharmacogenetic question of whether or not the strains would display differential responsivity to CDP challenges. No strain differences were discovered in relation to the latency to begin feeding, the response to familiar food, or the frequency of rearing in the 10 min food preference test. However, clear differences did emerge in relation to the animals' responses to novel foods. In contrast to the RCA and RHA lines, RLA rats sampled a greater variety of the available foodstuffs, and devoted a greater duration to the consumption of novel foods. Despite previous reports that under conditions of mild stress, RLA animals display greater emotionality, there was no evidence from the present study to show that RLA animals were more neophobic (a possible index of emotionality) than the other two Roman lines. Indeed, the evidence clearly suggests that RLA animals may under certain circumstances pay greater attention to novel cues. CDP treatments produced reductions in rearing, reductions in eating latency, and strongly potentiated the time devoted to feeding. Effects of CDP treatments on familiar and novel foods were dissociable. CDP at 10 mg/kg reliably increased the novel food feeding duration, an effect occurring mainly within the first 5 min of the test. CDP at 5 and 10 mg/kg reliably increased familiar food feeding duration, but this effect was in evidence for both halves of the test. Despite the multiple significant effects of CDP treatments in the food preference test, as well as the capacity of the test to demonstrate selective behavioral differences between the Roman lines, no evidence emerged for a significant interaction between strains and CDP treatments. So far as the behaviors measured in the food preference test were concerned, there was no differential sensitivity separating the Roman strains in response to CDP treatments.

Dietary selectivity in the field and food preferences in the laboratory for two herbivorous fishes (Cebidichthys violaceus and Xiphister mucosus) from a temperate intertidal zone

Diets and food selectivity of two stichaeid fishes (Cebidichthys violaceus and Xiphister mucosus) from the rocky intertidal zone of the central California coast (USA) were studied at each season of the year by gut content analysis and abundance measurements of potential macrophyte food items. Both fishes, after reaching a standard length of about 44 mm, were almost exclusively herbivorous. The bulk of the diet consisted of 8 to 10 species of chlorophytes and rhodophytes. These main dietary components were chiefly annual seaweeds with high surfaceto-weight ratios (sheetlike forms or small, highly branched forms). Perennial seaweeds were eaten in relatively large amounts only during the winter. Macrophytes eaten in only trace amounts included about 20 species of chlorophytes, chrysophytes, phaeophytes, rhodophytes and a spermatophyte. The small amount of animal material in the diet (never more than 2% by weight) could well have been ingested incidentally while the fishes were feeding on seaweeds. Food preference tests with up to 19 macrophyte species in the laboratory revealed that both fishes chose to eat three annual rhodophytes (Smithora naiadum, Porphyra perforata and Microcladia coulteri) in preference to Ulva lobata, an annual chlorophyte that was more abundant in the diets of field-caught specimens.

Evidence of a role for GABA in benzodiazepine effects on food preference in rats.

It has previously been shown that chronic treatment with the GABA-transaminase inhibitor ethanolamine-O-sulphate (EOS), which elevates brain GABA levels by around 200%, selectivity enhances novel food consumption in rats treated with chlordiazepoxide (CDP) and given a food preference test. To replicate and extend these findings, the effects of two doses of CDP with and without EOS pretreatment were compared with those of EOS or saline alone. EOS alone had no significant effects except to decrease eating rate but, in combination with 2.5 mg/kg CDP, it antagonised the increase in weight of familiar food eaten found with CDP alone and marginally increased weight eaten and duration of novel foot eating episodes. EOS magnified the effects of 5.0 mg/kg CDP to increase markedly the weight eaten and duration of episodes for novel chocolate drops. As no additive effects of EOS and CDP on rate of eating were found, the results are consistent with a facilitation of novel food consumption by an anxiolytic action of the two drugs, rather than by a rate-retarding action which might bias animals toward novel food. Finally, that EOS alone did not mimic the effects of CDP suggests that the role of GABA in the anxiolytic action of CDP may be indirect.

Effects of chronic chlordiazepoxide treatment on novel and familiar food preference in rats.

Chlordiazepoxide (CDP) given acutely has been found to have dose-related effects in rats given food preference tests. Low doses selectively increase consumption of familiar food, while high doses increase novel food consumption. The present study examined the effects of three doses of CDP given chronically. All doses (2.5, 5.0 and 10.0 mg/kg) selectively increased novel food eating. There was some evidence for a selective retardation of eating rate for familiar food and an enhanced taste preference for sweet food in CDP-treated rats. However, the overall results suggest that increased consumption of novel food represents an antineophobic action of CDP, which is potentiated by chronic treatment over a low to medium dose range.

Food preference following acute or chronic chlordiazepoxide administration: tolerance to an antineophobic action.

Chlordiazepoxide (CDP) at 15 mg/kg produced two distinct actions in a food preference test, firstly a general appetite-enhancing effect, and secondly an anti-neophobic effect. Following acute injection of CDP the rats changed from eating predominantly familiar food to a novel food. This may signify an anti-neophobic effect of CDP. However, following 10 days of treatment with CDP, the anti-neophobic effect was abolished and the choice of familiar food was enhanced. This could be an indication of a more general appetite-enhancing effect. Hence some form of tolerance may develop to CDP's effects over 10 days of treatment which selectively abolishes anti-neophobic action whilst leaving the appetite effect further enhanced. There were no indications of tolerance developing to the actions of CDP in animals familiarized with all the test foods before the preference test was run. Hence the presence of food novelty may be critical to the observation of some form of selective tolerance.

Effects of benzodiazepines and naloxone on food intake and food preference in the rat

After four days of administration, chlordiazepoxide (5 mg/kg) increased the weight gain of rats on ad libitum food and water, whereas chlordiazepoxide (7·5 mg/kg) and lorazepam (0·25 and 0·5 mg/kg) decreased it. After a period of food deprivation, chlordiazepoxide (7·5 mg/kg) and lorazepam (0·5 mg/kg) increased food consumption after ½, 2 and 6 h. In a food preference test chlordiazepoxide (5 mg/kg) enhanced consumption of chocolate chips, whereas lorazepam (0·25 and 0·5 mg/kg) enhanced consumption of familiar chow. Chlordiazepoxide (5 and 7·5 mg/kg) enhanced consumption of unfamiliar chow, whether this was preferred or not, whereas lorazepam (0·25 and 0·5 mg/kg) enhanced consumption of familiar chow. Naloxone (4 mg/kg) reduced food intake in the first ½ h after injection and reduced consumption of unfamiliar chow. Naloxone (2 and 4 mg/kg) abolished consumption of chocolate chips in the food preference test.

Effects of chlordiazepoxide and diazepam on feeding performance in a food-preference test.

Chlordiazepoxide (5 and 10 mg/kg) and diazepam (2.5 mg/kg) reduced the latency to eat and enhanced feeding response to familiar food in a food-preference test. The increased feeding response resulted from an increased frequency of individual eating episodes (bouts) without significant change in the episode duration. Experiment II indicated that this facilitatory action of the two drugs was not dependent on the presence of principal novelty cues in the food-preference test. Diazepam (5 mg/kg), in contrast, enhanced the feeding responses to novel food in the food preference test. Experiment III demonstrated that although diazepam can counteract induced food neophobia, its facilitory action on the response to novel foods may be mediated by a mechanism which can operate independently of food neophobia.

The Influence of Carrier of Gustatory Stimulation on the Cephalic Phase of Canine Pancreatic Secretion

The pancreatic secretory responses of dogs to various taste stimuli were examined in this study. Additionally, taste preferences were examined in 24-hour exposure tests to taste stimulus solutions as well as in short exposure tests to taste solutions mixed with commercial stock diet. The liquid and solid food preference tests produced quite different results. In dogs with cannulated gastric and duodenal fistulas, gustatory receptors were stimulated orally with 100 ml of taste stimulus solution (water 0.05 M monosodium glutamate (MSG), 0.05 M citric acid or 0.3 M sucrose) mixed with 25 g of a carrier (commercial stock diet, purified diet or cellulose). Pancreatic secretory responses to the taste stimuli varied with the type of carrier. Stock diet carrier was a better stimulant than the purified diet for both protein output and volume flow. Taste stimuli with a cellulose carrier did not produce any pancreatic response at all. The differences in responses to the different carriers were greater than the differences between taste stimuli when the same carrier was used. This experiment indicates that gustatory stimulation does influence the function of pancreatic secretion depending on the carriers used.

Effects of spiperone on feeding performance in a food preference test.

Spiperone reduced latency to feed and prolonged the total duration of feeding in a food-preference test in which novel and familiar foods were presented simultaneously to food-deprived rats. The increase in feeding duration could be accounted for in terms of an increase in time devoted to eating the novel foods, leaving the time devoted to eating the familiar food relatively unaltered. However, closer analysis of the data revealed that, at the level of mean duration of individual eating episodes, spiperone prolonged the eating-episode duration equally for both novel and familiar foods. This apparent paradox was resolved by noting that whilst spiperone did not alter the number of eating episodes in the test, it did alter the ratio of eating episodes in favour of novel foods. The data was incorporated into a control system model which depicts actions of spiperone in the food-preference situation with total eating duration as the final behavioural output.

Influence of Collembolan Feeding Activities on Soil Metabolism at a High Arctic Site

The feeding biology of Hypogastrura tullbergi Schaffer and Folsomia regularis Hammer, the two most abundant species of Collembola on Devon Island, was examined. Gut contents of both species contained mainly organic matter, although H. tullbergi ingested significantly more fungus than F. regularis. In food preference tests H. tullbergi selected fungi over organic matter, whereas F. regularis preferred organic matter to fungus. At field temperatures, H. tullbergi grew rapidly on fungal diets, but lost weight on decaying organic matter. F. regularis showed similar growth rates on either fungus or organic matter. Transition Zone soil cores containing microorganisms and Collembola exhibited respiratory rates significantly higher than those containing microorganisms only, and this enhancement was greater than could be accounted for by the respiration of the animals themselves. Highest respiratory rates occurred in cores containing microorganisms and F. regularis. At the Beach Ridge this enhancement of soil metabolism in the presence of Collembola was less obvious, and it was suggested that abiotic factors were more important than biotic interactions in controlling soil respiration. Mechanisms whereby the different feeding habits of H. tullbergi and F. regularis might influence decomposition rates were discussed.

Enhanced choice of familiar food in a food preference test after chlordiazepoxide administration.

Chlordiazepoxide (5.0 and 10.0 mg/kg) increased the time spent eating familiar laboratory chow, in a food-choice test in which both familiar and novel food objects were available. Chlordiazepoxide did not affect the feeding response to the novel food. Prior handling of the rats and repeat testing affected feeding responses in the test, although in ways which were different from and independent of the effect of chlordiazepoxide. Chlordiazepoxide may facilitate feeding responses by a direct enhancement of feeding motivation, and not necessarily secondarily by either a release of suppression of feeding or as attenuation of anxiety evoked by unfamiliarity.

The Functional Morphology of the Mouthparts and Foregut in the Terrestrial Isopod Philoscia Muscorum (Scopoli, 1763)

This was found to be true for isopods by Jones (1972) who reviewed numerous descriptions by previous authors. Moreover in isopods details of proventriculus structure can also provide insight concerning the nature of ingested materials; a conclusion reached by Flasarov? (1967) in a comprehensive review of foregut structure. Thus by comparing the mouthparts and proventriculus of Philoscia muscorum (Scopoli, 1763) with those of other isopods, indications of the natural diet of this species may be obtained and then used to substantiate conclusions drawn from food preference tests in the laboratory. The proventriculus is also of physiological interest because the midgut caeca open through it into the intestinal tube. Thus this region is of importance in determining how and when digestive enzymes are mixed with the food. MATERIALS AND METHODS The mouthparts of Philoscia muscorum were prepared for structural studies by removing the head capsule intact. The whole capsule was treated for 30 minutes with 10% KOH, rinsed, stained for 15 minutes in each of fast green and acid fuchsin, rinsed again, dehydrated, cleared in euparal essence and transferred to euparal. The individual mouthparts were removed using electrolytically sharpened tungsten needles, mounted on separate slides, then drawn with the aid of a camera lucida. The mouthparts were observed functioning on specimens that had previously been starved for several days and then given blades of decaying grass, positioned so that the animals could feed while clinging to the undersides and edges of the blades. Thus the dorsal bulk of the head capsule did not obscure the mouthparts as they bit into the margins of the leaves. Feeding was observed directly under a stereomicroscope at a magnification of 100 x and indirectly using a Bolex Hl6 reflex cin? camera in conjunction with a Zeiss epitechnoscope, with subsequent frame by frame analysis of the feeding action on an L.W. 16 mm projector analyser.

Coulometric Recorder for Timing and Counting Events in the Field

An event recorder for timing and counting was developed specifically for field application. The new recorder uses inexpensive coulometers for data storage and requires only microwatts of power from long-lasting batteries. Stored data are retrieved from the recording cells with a simple laboratory readout instrument. Six of these recorders were used to record the number of visits and accumulated feeding time in a food preference experiment with ricefield rats (Rattus rattus mindanensis). The results indicated that such visit count and feeding time records can be used to estimate accurately food preference based on consumption and, with suitable regression equations, predict weight of food consumed. When accuracy was checked by simultaneous recordings at one of the feeders, readings from the coulometric recorders never deviated more than about + 6 percent from those obtained with conventional electromechanical counters and timers. These results show that valid measurements of activity can be made with the event recorders when used as rat feeding monitors. Other applications are suggested. J. WILDL. MANAGE. 40(2):278-282 Biological studies often require the counting and timing of events, and it is convenient if this can be done with automatic recording equipment. Unfortunately for the field biologist, most electromechanical counters and timers are expensive and complex devices that are designed for use in the laboratory. We developed a simple event recorder by using coulometers as data storage cells. These recorders offer several advantages to the field biologist: they are silent, battery-operated, long-lived, operationally simple, and relatively inexpensive (less than $20 in electrical parts). A special readout instrument recovers stored data and clears the cells for reuse. Our event recorders performed well when tested as feeding activity monitors in food preference tests with ricefield rats. The data recorded (number of feeding visits and accumulated feeding time) proved sufficiently accurate and sensitive to allow prediction of the food consumed. DESCRIPTION OF THE EVENT RECORDER The recorder system consists of two parts: a data recorder and a data readout instrument. The uniqueness of the recording syst m lies in its coulometric method of storing data for later retrieval.

Some aspects of herbivore-plant relationships on Caribbean reefs and seagrass beds

Fishes, particularly parrotfishes (Scaridae) and surgeonfishes (Acanthuridae) and the regular sea urchins (Echinoidea) are abundant, conspicuous, and in some areas commercially important consumers of algae and seagrasses in the Caribbean. Diet—food availability studies show that herbivores generally take food in proportion to its abundance and availability in the field. These studies combined with direct food preference tests indicate that some plants or parts of plants are avoided by herbivores. The possibilities of chemical or structural factors which render plants unpalatable are being investigated. Herbivores attain large population densities and their feeding activities greatly influence plant distributions and community structure. Dense algal growth generally occurs only in areas inaccessible to herbivores such as wave-washed reef surfaces or beachrock benches. Herbivores are also responsible for the halo region of sparse and grazed seagrasses separating reefs from surrounding seagrass beds. Experimental manipulations of herbivores on reefs lead to rapid changes in the structure of plant communities.

Altered food preferences after lesions in the basolateral region of the amygdala in the rat.

Rats with lesions in the basolateral amygdala chose different foods from control rats in 10-min. food-preference tests. The normal rats ate primarily familiar chow, while the amygdala-lesioned rats ate primarily novel foods. The lesioned rats did not select indiscriminately but showed definite preferences. With repeated testing, the normal rats' preferences became similar to those of the amygdala-lesioned rats. Food-preference tests in a disturbing environment suggested that the difference between the lesioned and control groups was not due to a general alteration in behavior such as fear. Other aspects of ingestive behavior, such as body weight regulation, were not primarily altered by the lesions. The basolateral amygdala may therefore be concerned with the selection of foods on the basis of previous experience. Amygdaloid neurons are activated in eating and drinking elicited by electrical stimulation of the lateral hypothalamus in rats (E. T. Rolls, 1972). This indication that amygdaloid neurons are involved in eating and drinking is strengthened by the finding that the amygdaloid neurons directly excited by the stimulation have the same absolute refractory period as the neurons through which the eating and drinking are elicited (E. T. Rolls, 1973). To investigate further the role of the amygdala in eating, ingestive behavior following amygdaloid lesions was analyzed, as described here. The lesion electrodes were aimed at the basolateral region of the amygdala, which is the area in which neurons were activated in the electrically elicited eating and drinking (E. T. Rolls, 1972). Electrophysiological and behavioral studies (see E. T. Rolls, 1972) support the hypothesis that the amygdala is involved in reinforcement. This hypothesis was utilized in the experiments described here. A choice of foods was given to the lesioned animals to determine whether the reward value of different foods measured by food preference is altered by the lesions.

Attraction of Coprophagous Beetles to Feces of Various Animals

Beetles were attracted to pit traps baited with the feces of one of 12 different animals in 3 habitats. Comparison of the 3 habitats showed marked differences in beetle fauna. Most dung beetles were captured in traps baited with swine feces. Swine and opossum feces attracted 57.7% of all beetles captured and 74.8% of the Phanaeus species which are the major intermediate hosts of swine spirurids in southern Georgia. Captured beetles comprised 12 genera with more than 18 species. The presence and abundance of coprophagous beetles in a given biome is determined by the supply of excrement for food. Other factors that may influence the distribution of these beetles are fauna, flora, solar radiation, temperature, soil type, soil pH, and rainfall. These factors are so closely linked that none can independently regulate the presence or absence of a given dung beetle species. The microclimatic conditions of animal droppings can restrict the small Aphodiinae, according to Landin (1961). Mohr (1943) reported that the environment in which dung is dropped has a profound effect on the composition of its fauna, i.e., droppings in densely shaded woods have a different set of dominant insects than those in sunny, open pastures. Many adult coprophagous beetles of the family Scarabaeidae are intermediate hosts of various helminths of domestic and wild animals. Phanaeus spp. have been found to be important intermediate hosts for spirurids of swine in southern Georgia (Porter, 1939; Stewart and Kent, 1963; Fincher, Stewart, and Davis, 1969). Cooper (1938), Ritcher (1945, 1966), and Lindquist (1933, 1935) found the adults of Phanaeus to be associated with cattle droppings while Miller (1954) found that Phanaeus igneus was one of the principal dung beetles burying human feces. Received for publication 11 November 1969. * Journal Series Paper No. 599 of the University of Georgia College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, Georgia 31794. t Animal Parasite Research Laboratory, Animal Disease and Parasite Research Division, ARS, USDA, Tifton, Georgia 31794. t Department of Entomology, University of Georgia, Athens, Georgia 30601. Present address: Market Quality Research Division, Stored Product Insects Research and Development Laboratory, USDA, ARS, Savannah, Georgia 31403. In a short-term food preference test using a limited number of animal feces, Stewart (1967) found that more dung beetles were attracted to swine feces than to the other feces tested. This paper reports a food attraction study of dung beetles to 12 different animal feces in three different habitats. This study was conducted in the same manner as the previous work by Stewart (1967) using the same three locations on the Georgia Coastal Plain Experiment Station, Tifton, Georgia. MATERIALS AND METHODS Replicas were made in each of 3 different habitats. One habitat was an open area on the Experiment Station dairy farm approximately 1 mile away from the nearest wooded area. Other than dairy cattle, the only other domestic animals within a 0.5 mile radius were farm dogs and several horses. The second area was located on the Experiment Station's swine farm. The only animals present in numbers in this area were swine, although some wild animals were probably in nearby woods. The third area was located in woods near the Animal Disease Laboratory of the Experiment Station, where cattle, chickens, dogs, ducks, horses, sheep, and swine have all been kept in an assortment of pens and lots for years. Of the 3 areas studied, this was the closest to what could be considered a wild habitat. The heavily wooded area extended from the trap site along the sides of a stream bed for a distance of a mile or more. The 3 areas were separated from each other by distances of 2 to 3 miles. At each of the 3 locations, 12 holes spaced 30 ft apart held a 1-lb. coffee can with the rim buried to ground level. Funnels 4 by 3 inches were placed in each can. The top of each funnel had a 2.25-inch metal disk attached across the funnel opening to hold the bait. A 1-inch clearance between the edge of the disk and the top edge of the funnel permitted beetles to fall through into the can. The feces from each animal were placed on the same funnel throughout the experiment at approximately 9:00 AM (EDT) each day. The pit traps were baited, emptied, and the funnels randomly moved to different cans at the time of baiting each day, to avoid a position bias. Daily

Food Habits of Two Sympatric Colorado Sciurids

The golden-mantled ground squirrel (Citellus lateralis lateralis) and the least chipmunk (Eutamias minimus consobrinus) were studied in the mountains of west central Colorado where the two species are sympatric and display marked similarities in habitat selection, life cycles and general behavior patterns. Detailed investigation of the energy relationships and food habits of these animals, including field observations, stomach-content analyses and food preference tests, demonstrated a slight divergence in general food preferences and a profound dependence by both species upon the common dandelion (Taraxacum officinale) for summer food. This plant provided more than 80% of the June–August diet of both chipmunk and mantled squirrel. The chipmunk preferred and consumed the flowers, seeds, and seed-laden heads of the dandelion, while the mantled squirrel preferred the stems and rarely ate the heads or seeds. These behavior patterns effectively removed, in part, the two sciurids from direct competition for energy sources in summer although their foraging territories greatly overlapped.

OBSERVATIONS ON THE FEEDING OF THE HEDGEHOG (ERINACEUS EUROPAEUS L.)

The feeding of the hedgehog in captivity is described and the degree to which this seems to be affected by hibernation.Altogether 167 food preference tests were performed by nine hedgehogs and the results seem to indicate that though hedgehogs will eat most of the small invertebrates that they find in their natural habitat, they consistently select some rather than others.