Non-preferred Food Research Articles

AN EVALUATION OF SIMULTANEOUS AND SEQUENTIAL PRESENTATION OF PREFERRED AND NONPREFERRED FOOD TO TREAT FOOD SELECTIVITY

In the current investigation, we compared two methods of food presentation (simultaneous vs. sequential) to increase consumption of nonpreferred food for 3 children with food selectivity. In the simultaneous condition, preferred foods were presented at the same time as nonpreferred food (e.g., a piece of broccoli was presented on a chip). In the sequential condition, acceptance of the nonpreferred food resulted in presentation of the preferred food. Increases in consumption occurred immediately during the simultaneous condition for 2 of the 3 participants. For 1 participant, increases in consumption occurred in the simultaneous condition relative to the sequential condition, but only after physical guidance and re-presentation were added to treatment. Finally, consumption increased for 1 participant in the sequential condition, but only after several sessions. These results are discussed in terms of possible mechanisms that may alter preferences for food (i.e., establishing operations, flavor-flavor conditioning).

Social transmission and memory of food preferences in pine voles (Microtus pinetorum).

The social transmission of food preferences is affected by factors including the length of time a preference is maintained. The authors investigated the social transmission of food preferences in pine voles (Microtus pinetorum) and whether food items had to be present for memory to persist. A demonstrator vole was fed cocoa-flavored food, a nonpreferred food. After interacting with a demonstrator vole, observer voles preferred cocoa-flavored food as compared with either naive voles that had not interacted with demonstrators or voles that had been exposed to odors. Observers retained this preference for 72 hr after interacting with an observer whether or not flavored foods were present. The ability to learn which food items are palatable and safe may benefit a generalist herbivore that has faced selection to avoid toxic baits.

Do earthworms help to sustain the slug predator Pterostichus melanarius (Coleoptera: carabidae) within crops? Investigations using monoclonal antibodies.

Earthworms provide a major potential source of alternative food for polyphagous predators, such as carabid beetles, that are natural enemies of slugs, aphids and other agricultural pests. Non-pest prey may foster larger numbers of natural enemies, which then help to control pests, or alternatively may help to divert the predators away from pest control. An earthworm-specific monoclonal antibody was developed to study carabid-earthworm interactions in the field and assess the role of earthworms as alternative prey. The antibody could identify as little at 7 ng of earthworm protein in an ELISA, and could detect earthworm remains in the foregut of the carabid beetle Pterostichus melanarius for 64 h after consumption. Thirty-six per cent of field-collected beetles contained earthworm remains. Quantities of earthworm proteins in the beetle foreguts were negatively related to total foregut biomass, suggesting that earthworm consumption increased as total prey availability declined. There was also a negative relationship between foregut biomass and beetle numbers, but both quantities and concentrations of earthworm proteins in beetle foreguts were positively related to beetle numbers. This suggests that as beetle activity-density increased, total prey availability declined, or, as prey availability declined, beetles spent more time searching. In these circumstances, beetles fed to a greater extent on earthworms, an acceptable but nonpreferred food item. Earthworms may, therefore, provide an ideal alternative prey for P. melanarius, helping to sustain it when pest numbers are low but allowing it to perform a 'lying-in-wait' strategy, ready to switch back to feeding on pests when they become available.

Chemosensory discrimination of plant and animal foods by the omnivorous iguanian lizard Pogona vitticeps

Most iguanian lizards are insectivores that do not use chemical cues sampled by tongue-flicking to identify prey before attacking, but the sole iguanian herbivore previously studied did so. To investigate the effects of a partially herbivorous diet on responses to food chemicals, I conducted an experiment to determine whether the omnivorous bearded dragon (Pogona vitticeps) has a similar ability. Chemical stimuli from crickets and carrots, both preferred foods, and alfalfa sprouts, and deionized water (a nonpreferred food and odorless control, respectively) were presented on cotton-tipped applicators. The lizards responded more strongly to both preferred foods than to the controls, performing more tongue flicks and biting the cotton in a greater number of trials. It is hypothesized that lingually mediated food-chemical discrimination is useful to herbivorous and omnivorous lizards for identifying plant and animal foods and for evaluating the quality of plant foods. The insectivorous ambush foragers ancestral to P. vitticeps could not locate prey by tongue-flicking repeatedly at an ambush post and do not exhibit prey-chemical discrimination. Adding plants to the diet altered the selective milieu because plants approached using visual cues can be evaluated using chemical cues, allowing the evolution of the ability to discriminate between plant-food chemicals. The ability to identify animal prey by tongue-flicking may have evolved through correlated evolution with chemosensory identification of plants or specifically for locating or identifying immobile prey.

The rewarding properties of neuropeptide Y in perifornical hypothalamus vs. nucleus accumbens

There is a high coexistence of substance abuse in humans with eating disorders. One theory offered to account for this fact is that a common biochemical substrate may exist that mediates both processes. Brain neuropeptide Y (NPY) is one neurochemical system that might contribute to these separate, yet related, problems. To clarify the role of NPY in mediating reward processes and the possible interaction between reward and feeding, the present study examined the effects of injecting NPY bilaterally into the perifornical hypothalamus (PFH) vs. the nucleus accumbens (NAC) on intake of preferred vs. non-preferred food types, as well as on conditioned place preference (CPP) learning. NPY (24, 78, 156 and 235 pmol/side) stimulated intake of both regular powdered chow and sucrose when injected into the PFH, but not the NAC. A CPP that was negatively correlated with food intake occurred with the low (24 pmol/side) dose of NPY in the PFH, while a CPP that was not correlated with food intake was produced with the same dose in the NAC. The extent of the CPPs produced by NPY injection in both brain sites mirrored that produced by peripheral injection of amphetamine (2.5 mg/kg). These results indicate that NPY elicits reward-related behavior, but not feeding, from the NAC, and both behaviors from the PFH. However, the feeding effect derived from the PFH appears to overshadow a rewarding effect derived from this site. Considered together, these findings suggest that altered NPY functioning in both brain regions may contribute to some of the pathophysiological processes observed in eating disordered patients who have additional proclivities for substance abuse.

The Effect of Changes in Availability on Food Selection at Different Levels of DeprIvation

In the present study, two experiments investigated the effect of a change in food availability on selection between two food items at different deprivation levels. In the first study, 6 pigeons chose between a nonpreferred food item (i.e., checkers) after a fixed delay and a preferred food item (i.e., corn) after an adjusting delay. The delay to the preferred food item adjusted depending upon the pigeon’s choices. The dependent measure was the amount of delay added to corn to produce indifference at 70% and 95% of body weight. Results showed that less delay had to be added when pigeons were more deprived. In the second study, the availability of both corn and checkers was varied by manipulating the amount of each food item presented to the pigeons at 70% and 95% of body weight. The dependent measure was the amount of each item taken. For the nonpreferred food item, consumption depended on an interaction between deprivation and availability. A decrease in availability only affected checker consumption when body weight was at 70%. Together these two studies showed that the effect of a change in food availability on selectivity was greater when pigeons were more deprived.

Naltrexone administered to central nucleus of amygdala or PVN: neural dissociation of diet and energy.

There is evidence that opioids may affect food consumption through mechanisms as diverse as reward or energy metabolism. However, these hypotheses are derived from studies employing peripheral or, more rarely, intracerebroventricular administration of drugs. Opioid receptors have a wide distribution in the central nervous system and include a number of regions implicated in food intake such as the hypothalamic paraventricular nucleus (PVN) and the central nucleus of the amygdala (ACe). It is not known whether local opioid receptor blockade in either of these regions will produce similar effects on food intake. To examine this issue, a chronic cannula was aimed at either the PVN or ACe of rats that were fed a choice of a high-fat and high-carbohydrate diet, which allows for the measurement of both preference and total energy consumption. Naltrexone influenced preferred and nonpreferred food consumption, depending on the site of administration. Consumption of both preferred and nonpreferred diets was suppressed after PVN naltrexone administration, whereas only preferred diet intake was reduced after ACe injection of naltrexone. The present evidence indicates that direct stimulation of different brain regions with naltrexone may be associated with diverse effects on diet selection, which may be accounted for by manipulation of specific functional neural circuitry.

Do Spalax ehrenbergi blind mole rats use food odours in searching for and selecting food?

This laboratory study examined responses of Israeli blind subterranean mole rats (of the Spalax ehrenbergi superspecies) to food odours (Narcissus tazetta and Urginea maritima bulbs) and assessed to what extent mole rats’ odour preferences are indicative of their food preferences and whether these preferences influence their foraging behaviour. Prior to odour testing, mole rats ate Narcissus bulbs preferentially and avoided Urginea bulbs when both types of bulbs were available, as is the case in nature. In phase 1, mole rats (n = 20) spent significantly more time sniffing the odour of Narcissus bulbs than the odour of Urginea bulbs, indicating a preference for the odour of the preferred bulb. In phase 2 in a six-tunnel radial arm maze, the presence of preferred or non-preferred food odours at the ends of the 20 em tunnels did not affect mole rats’ (n = 12) movement into the tunnels. The results suggest that mole rats can identify food items by their odours and thus can discriminate between edible (e.g., Narcissus) and poisonous (e.g., Urginea) bulbs without the necessity of biting into them. Because there is limited air movement in mole rats’ sealed tunnel systems, the food odours do not travel far underground, and thus mole rats probably do not use detection of airborne food odours to facilitate their foraging underground. Our results suggest that mole rats could use food odour discrimination to select edible food items for collection and to sort food items in their nest stores.

Chemosensory discrimination of plant and animal foods by the omnivorous iguanian lizard <i>Pogona vitticeps</i>

Most iguanian lizards are insectivores that do not use chemical cues sampled by tongue-flicking to identify prey before attacking, but the sole iguanian herbivore previously studied did so. To investigate the effects of a partially herbivorous diet on responses to food chemicals, I conducted an experiment to determine whether the omnivorous bearded dragon (Pogona vitticeps) has a similar ability. Chemical stimuli from crickets and carrots, both preferred foods, and alfalfa sprouts, and deionized water (a nonpreferred food and odorless control, respectively) were presented on cotton-tipped applicators. The lizards responded more strongly to both preferred foods than to the controls, performing more tongue flicks and biting the cotton in a greater number of trials. It is hypothesized that lingually mediated food-chemical discrimination is useful to herbivorous and omnivorous lizards for identifying plant and animal foods and for evaluating the quality of plant foods. The insectivorous ambush foragers ancest...

Lethal Toxins in Non-preferred Foods: How Plant Chemical Defences Can Drive Microtine Cycles

We hypothesize that periodic lethal toxin production by non-preferred food species can explain the precipitous decline phase of vole cycles in arctic and alpine tundra regions. For plants that cannot respond to grazing damage by compensatory shoot growth, periodic production of toxins can have an adaptive advantage at the individual level. Several plants in the diet of cyclical small mammals do produce lethal toxins and some production is known to be cyclical. Despite the wealth of indirect and anecdotal observation in support of the hypothesis, there remains a lacuna in the hard core of evidence: periodic production of lethal toxins and toxin-related deaths in microtines. We argue that this is only because it has not been sought among likely plants or has been sought at the wrong place or time. Strong candidate species are non-preferred foods with circumpolar distributions such asEmpetrum nigrumorVaccinium uliginosum. The right place to expect lethal toxin production is the high altitude or latitude epicentres of population crashes, in regions where recovery is by immigration as well as births; the right time is at the cusp of the crash. We propose an experimental design to test the hypothesis.

Cultural Influences on Sharer and Recipient Behavior

Seventy-two 4-year-old Chinese and Indian children were paired with a friend and with an acquaintance in their class. One child (sharer) was given 10 pieces each of his or her preferred and nonpreferred foods, whereas the partner (recipient) was given one piece of each of the same foods. Sharing incidents were classified to indicate whether they were initiated by the sharer (spontaneous sharing) or due to the recipients’ behavior (elicited and passive sharing). Friendship did not influence either the quantity or quality of sharing. Results indicated that young Asian children were more likely to share spontaneously and less likely to elicit sharing. Chinese children showed more spontaneous sharing than did Indian children; the majority of sharing incidents in the Indian sample were classified as passive sharing. Findings highlight the importance of cultural beliefs on young children’s behavior and of considering the interactive effects of the sharers’ and recipients’ behaviors on each other.

273 Objective evaluation of the psychophysiological response induced by preferred or non-preferred foods

The importance of perceived complexity, a ‘collative property’ as defined by [Berlyne, D. E. (1967). Arousal and reinforcement. In Nebraska symposium on motivation (pp. 1–110). University of Nebraska Press], to the dynamic development of preference was investigated. Eighty-six female and 82 male subjects rated their liking for and various collative properties of seven very similar orange drinks that differed only in perceived complexity as a result of adding small quantities of other flavours. This was done before and after giving each subject extended experience of one of the drinks, each being used equally often for this purpose. As predicted by the theory of [Dember, W. N., & Earl, R. W. (1957). Analysis of exploratory, manipulatory and curiosity behavior. Psychological Review, 64 (2), 91–96] exposure to a stimulus with a slightly higher complexity than an individual subject’s optimally preferred level of perceived complexity, caused an upwards shift in that level, whereas exposure to a less complex stimulus had no such effect. Changes in the appreciation of the drinks predicted by the theory were also observed.

Adaptations to and Consequences of an Herbivorous Diet in Grouse and Waterfowl

I review diet selection in grouse and waterfowl in the context of their herbivorous diets and discuss adaptations to herbivory in these groups. Both grouse and waterfowl prefer plant foods containing higher concentrations of protein than nonpreferred foods; grouse and small waterfowl include invertebrates in the diet to meet protein demands during periods of high tissue production. Grouse tend to avoid plant foods containing high concentrations of anti-herbivore compounds and the relative roles of these compounds versus nutrients in diet selection by grouse is presently unclear. Grouse and waterfowl have similar digestive morphology, except for the ceca, which are 5 times longer in grouse than in geese. Enlarged ceca are associated with improved nitrogen economy in grouse; evolution of these structures in geese may have been precluded by energetic costs of carrying enlarged ceca during migration.

Diet choice and nutrition of captive snowshoe hares (Lepus americanus): Interactions of energy, protein, and plant secondary compounds

:We examined consumption and digestibility of winter browse in captive snowshoe hares (Lepus americanus Erxl.) to determine how energy content, protein quality and plant secondary chemicals interact to affect their diet choice and nutrition. We found that preferred foods of snowshoe hares have higher apparent digestibilities of dry matter and energy than nonpreferred foods. Digested crude protein was unaffected by increased consumption of preferred foods, but declined when hares consumed nonpreferred foods. Rate of weight loss in hares increased with increasing consumption of nonpreferred twigs. Hares did not compensate for low protein or low energy content by eating more twigs. Weight changes were correlated with the energy content of the food and its digestibility, whereas consumption was correlated with phenol and protein content. If hares can increase consumption of preferred foods, they may simultaneously meet both their energy and protein requirements. If they are obliged to increase consumption of nonpreferred foods, then protein requirements may never be met due to the effects of secondary compounds. During periods of limited food availability, snowshoe hares should select a mixed diet that may include small quantities of poor-quality food items, regardless of preference, allowing them time to find good-quality foods.

Use of cues by grazing animals to locate food patches: an example with sheep

The ability of sheep to form spatial associations between two cues and two food rewards and to distinguish between the two cues prior to grazing them was examined. At 12 locations within a long, thin field, individual sheep chose between a pair of patches (plastic bowls) containing either preferred (cereal pellets) or non-preferred (lucerne, Medicago sativa pellets) food. Each patch had either a turf of perennial ryegrass ( Lolium perenne) or white clover ( Trifolium repens) associated with it as a cue. The cues were placed in wire mesh cages immediately in front of each patch. The cage meant the cue could be seen and smelled, but not eaten. Each sheep received a series of trials in one of three cue-patch associations: (i) ‘WC’, preferred patch always behind white clover and non-preferred patch always behind ryegrass; (ii) ‘RG’, preferred patch always behind ryegrass and non-preferred patch always behind white clover; (iii) ‘R’, preferred and non-preferred patches associated with cues at random. Five sheep were tested with each association. The spatial location of the food patches and cues was randomised within trials and rerandomised between successive trials to preclude animals from using spatial memory to locate patches. In the first trial, the proportion of times that the preferred food patch was chosen first at each pair of patches was similar in the WC (0.42), RG (0.46) and R (0.48) associations. In the sixth trial, the proportion of times that the preferred food patch was chosen first at each pair of patches was greater in the WC (0.81) and RG (0.82) associations than in the R association (0.46). The WC and RG data indicate that sheep formed associations between cues and rewards and distinguished between the two cues by sight or smell. The ability to form flexible associations between cues and food would be an important mechanism, acting independently of memory of spatial locations, that would help sheep select diets that are better than the average in spatially and temporally complex food environments. The ability to discriminate between white clover and ryegrass prior to grazing them indicates that the mixed diets (partial preference) exhibited by sheep given a choice between these two species do not simply arise because of a need for the sheep to sample the two species to know what each species is.

Treating chronic food refusal in young children: home-based parent training.

We evaluated the effects of behavioral parent training program on parent and child feeding-related behaviors in the home. We trained mothers to initiate regular offerings of previously rejected (target) foods and to provide contingent attention (i.e., specific prompts, positive reinforcement) to increase their child's acceptance of nonpreferred foods. For 1 subject, we also directed training at increasing self-eating. Results of a nonconcurrent multiple baseline design across 3 mother-child dyads demonstrated that, with training, all mothers increased offerings of target foods and use of specific prompts, and 2 mothers increased levels of positive attention. In turn, children increased their acceptance of target foods and self-eating, thus demonstrating the functional effects of parent training on in-home meal times. Temporary increases in food refusals occurred when treatment was initiated but declined as treatment continued. We discuss the results in terms of the potential benefits and limitations of a home-based treatment model.

Children's Lunch Intake: Effects of Midmorning Snacks Varying in Energy Density and Fat Content

To determine the effects of preloads differing in energy density and fat content on subsequent lunch intake, 24 preschool children 113 g ice-cream preloads as mid-morning snacks (containing 0, 12, or 18 g of fat, and 4 g of protein), followed nearly 2 h later by an ad libitum lunch consisting of a variety of foods. A fat-free baseline preload, consisting of dry cereal and apple juice, was also included. The baseline, fat-free, medium and high-fat preloads contained 334, 740, 953, and 1150 kJ per serving. All three ice-cream preloads produced significant but equivalent suppression of ad libitum lunch intake relative to baseline; lunch intake was not related to the fat content or energy density of the ice-cream preloads. Compensation at lunch was not macronutrient specific; children did not increase their fat intake at lunch following the fat-free preload. As energy and fat content of the preloads increased, children consumed significantly fewer foods at lunch, confirming previous findings. These changes in the variety of foods consumed were related to preference: regardless of preload, children continued to consume their preferred foods, while non-preferred foods tended to be eliminated following the higher energy preloads. Because compensation for energy was incomplete, energy intake of meals plus snacks increased with the energy content of the preload. Additional research is required to determine whether manipulating the fat and energy content of snacks produces similar effects when the unit of analysis is the child's total daily diet, rather than a single meal.

Food-elicited vocalizations in golden lion tamarins: design features for representational communication

Abstract. These studies were performed to determine whether, and what type of, information is contained in the vocalizations uttered by golden lion tamarins, Leontopithecus rosalia, to 12 different foods. Information encoded may be of two general types: (1) affective: when the signal contains emotional and/or individually identifying information, or (2) representational: when the signal contains information about events external to the sender in addition to any affective information. Six tamarins were presented with all possible pairs of 12 foods. Data were collected on the food chosen and on the latency to choose. Preference hierarchies were constructed for each tamarin, and a general preference hierarchy was constructed for all the tamarins. A within-groups ANOVA indicated that the tamarins had significant preference differences. The tamarins seem to divide their food into two preference categories: preferred foods (mealworms, grapes, raisins, dried pineapple, crickets) and non-preferred foods (cooked chicken, raspberries, kiwi fruit, dried apricot, walnuts, peanuts, and sunflower seeds). The vocalization rate to the 12 foods in this study were significantly correlated with food preference scores for those foods, and there were significant differences between the vocalization rate given to preferred foods versus non-preferred foods. Multivariate analysis of variance (MANOVA) conducted on the five preferred foods revealed significant differences between the vocalizations uttered in the presence of different foods, and discriminant function analysis revealed that there was enough information in the vocalizations to correctly predict the elicitor 52% of the time, when the foods were grouped as protein, dried fruit and grape.

Food preference of young rhesus monkeys fed marginally zinc deficient diets

Zinc deprivation has been shown to produce hypogeusia in rhesus monkeys but the possible consequences of altered taste sensitivity for food preference and selection is not known. We studied 13 rhesus monkeys (2.5 to 3 years of age) for food preference in a structured choice situation. These animals were fed two levels of dietary zinc: marginally zinc deprived (fed 4 µg zinc/g diet from conception and throughout development;N=6), or control (fed a 100 µg zinc/g diet throughout the study;N=7). Preference for familiar vs unfamiliar food items, order of food preferences, persistence in retrieval of preferred and nonpreferred foods, and preference under four deprivation periods were examined. Animals were offered a choice of two food items, both containing minimal zinc levels, and food choice and latency of choice were measured. Results indicate that animals fed the marginal zinc diets had reduced preference for unfamiliar foods relative to controls and different patterns of food preference. These results may be relevant to maintenance of appropriate food selection in marginally zinc deprived populations.

Heart rate changes during consumption of preferred and non-preferred food under amphetamine treatment

Heart rate was recorded in five dogs while they ate three kinds of foods varying in preference. Heart rate increased during the initial phase of eating, to the greatest extent with the most preferred food. dl-Amphetamine sulfate (0.2 mg/kg) injected intramuscularly produced a general decrease of heart rate. Nevertheless, the heart rate increase during first period of eating was as great as before treatment. Furthermore, the difference in heart rate increase between the most and least palatable foods was still present, and in some dogs even enhanced. It was concluded that amphetamine at this dose in dogs does not attenuate the hedonic properties of food, but may even intensify them. Therefore, the food intake-reducing effect of amphetamine cannot be due to its suppression of hedonic value of food but is the result of its action on other mechanisms such as hunger drive or control of movement.