Efeitos da alteração dos níveis de ansiedade no desempenho de ratos em uma tarefa de discriminação apetitiva

The plus-maze discriminative avoidance paradigm has been used to study the relationship between aversive memory and anxiety. The present study aims to verify if the elevated plus-maze can provide information about appetitive memory and anxiety, through a task motivated by food reward. Animals were allowed to explore an elevated plus-maze and received reinforcement in one of the enclosed arms. In a test session performed 24h later, in the absence of reward, rats showed preference for the previously rewarded enclosed arm over the neutral enclosed arm. The administration of diazepam and pentylenetetrazole before training induced, respectively, anxiolytic and anxiogenic effects (as evaluated by open-arm exploration). Both drugs induced amnestic effects, i.e., lack of preference for the rewarded arm in the test session. The results suggest that appetitive memory can be influenced by anxiety levels as well. The plus-maze appetitive discrimination task seems to be a useful model to investigate the relationship between memory and anxiety

Efeitos de vocalizações de co-específicos e do escuro sobre o ritmo circadiano da atividade motora em sagüis (Callithrix jacchus)

The principal zeitgeber for most of species is the light-dark photocycle (LD), though other environment factors as food availability, temperature and social cues may act. Daily adjustment of the circadian pacemaker may result from integration of environmental photic and non-photic cues with homeostatic cues. Characterization of non-photic effects on circadian timing system in diurnal mammals is scarce in relation to nocturnal, especially for ecologically significant cues. Thus, we analyzed the effect of conspecific vocalizations and darkness on circadian activity rhythm (CAR) in the diurnal primate Callithirx jacchus. With this objective 7 male adults were isolated in a room with controlled illumination, temperature (26,8 ± 0,2°C) and humidity (81,6 ± 3,6%), and partial acoustic isolation. Initially they were under LD 12:12 (~300:2 lux), and subsequently under constant illumination (~2 lux). Two pulses of conspecific vocalizations were applied in total darkness, separated by 22 days, at 7:30 h (external time) during 1 h. They induced phase delays at circadian times (CTs) 1 and 10 and predominantly phase advances at CTs 9 and 15. After that, two dark pulses were applied, separated by 14 days, during 1 h at 7:30 h (external time). These pulses induced phase delays at CTs 2, 3 and 18, predominantly phase advances at CTs 8, 10 and 19, and no change at CT 14. However, marmosets CAR showed oscillations in endogenous period and active phase duration influenced by vocalizations from animals outside the experimental room, which interfered on the phase responses to pulses. Furthermore, social masking and relative coordination with colony were observed. Therefore, phase responses obtained in this work cannot be attributed only to pulses. Afterwards, pulses of conspecific vocalizations were applied in total darkness at 19:00 h (external time), during 1 h for 5 consecutive days, and after 21 days, for 30 consecutive days, on attempt to synchronize the CAR. No animal was synchronized by these daily pulses, although oscillations in endogenous period were observed for all. This result may be due to habituation. Other possibility is the absence of social significance of the vocalizations for the animals due to random reproduction, since each vocalization has a function that could be lost by a mixture of sounds. In conclusion, conspecific vocalizations induce social masking and relative coordination in marmosets CAR, acting as weak zeitgeber

Caracterização da neofobia alimentar em crianças de três a seis anos

Alimentation is essential in life. Concerning omnivores, characterized by the necessity of a varied diet to satisfy their metabolic needs, it is extremely advantageous the assumption of new foods. However, the assumption of new unknown foods is, potentially dangerous, because of possible intoxications. In this sense, one of the most important behaviors related to reducing risks is the so called food neophobia, characterized by the rejection of new foods and/or an ingestion of very little amounts. The aim of the present study was to investigate if age, sex and socio-economical status were able to influence food neophobia. The neophobia has been described in a range of 3-6 years old children taken both from public and private schools within the city of Natal-RN. Four different type of ice-creams, each one characterized by a different flavor, have been utilized. Two flavors were known to the young and the remaining two flavor were new. We didn't find significant differences between the investigated variables. However, the exploitation of data from the survey conducted showed that the ease or not to accept new foods obtained, was correlated with the variables under the same guidelines observed in literature. Aspects related to the stimulus used probably eased the neophobic answer. Then, it is suggested that the food neophobia can be influenced by sex, age and socioeconomic factors of individuaIs. Neophobia tends to be more common in girls, with ages between three to four years old and with a low leveI socioeconomic. In this sense, given the importance of kid neophobic reaction to the development of dietary patterns of other life's stages, it is necessary to make further studies to better explain this phenomenon. Given the pivotal role of food neophobia to the development of alimentary habits within all ages of life, other studies will be necessary for a better comprehension of such phenomena. Key-words: food neophobia; Evolutionary Psychology;children food intake; diet restriction; children's diet development

Estudo da preferência manual durante o desenvolvimento ontogenético em sagüi comum ( Callithix jacchus)

The study of manual preference is a widely used approach to investigate cerebral laterality in nonhuman primates. However, in New World primates, little is known about the ontogenesis of hand use asymmetry, in both forced and spontaneous activities, as well as how they correlate with sexual hormones. Accordingly, a longitudinal study was conducted on the manual preference of 6 female and 4 male common marmosets (Callithrix jacchus). The study included the record of forced tests to reach for the food using only one hand (forced activity) and activities such as grooming (auto and social), scratching, grasping the food and hanging, in weekly sessions from the infantile (4 months) to the early adult phase (15 months). Feces samples were also collected, at least once a week, to evaluate the level of gonadal steroids and their influence on these behaviors. In the forced activity, the results confirm the influence of the development period on manual preference during feeding, shown by the increase in lateral stability when grasping the food between the juvenile and adult phases. During this period, a sexual hormone effect on development was also observed, mainly of progesterone in females and androgen in males, but no difference between sexes was found. In the females, progesterone also influenced the manual preference index, with a proportional increase in the degree of manual asymmetry during puberty. With respect to spontaneous activities, the animals showed proportional use of both hands when scratching, hanging, holding the food and grooming. A positive correlation was also found between the preference for holding the food in forced activities and in spontaneous activities

O gato doméstico (Felis catus) responde à sinais gestuais? possíveis implicações do convívio social

The cats (Felis catus) were domesticated about 9,500 years ago due to the advent of agriculture, being used to control the pests that devastated the food harvested. These animals went through an artificial selection and over generations and millennia had their behavior and morphology changed by humans. This process of domestication by man gave rise to a special ability, the understanding of human pointing gestures, clearly noticed while we feed our pets. Our goal in this study was to assess the comprehension of pointing gestures by cats and also verify the influence that social interactions exerts on the development of this ability. We found that experimental subjects from both groups, solitary animals and social animals, were able to follow human indication in order to find hidden food. However, social interaction had no effect on cats performances. The ability tested here probably evolved during the process of domestication of this species, and social interaction seems to exert little or no influence upon its expression

Comportamento alimentar do camarão marinho farfantenaeus subtilis em condições laboratoriais

Shrimp culture represents an important activity to brazilian economy. The northeastern region has presented high levels of production because of its climatic conditions. An important factor for the activity´s major development is related to the introduction of the species Litopenaeus vannamei. The use of an exotic species can disturb the ecosystem. In the last decades, L. vannamei has been the only species cultivated in Brazilian farms, there not being an alternative species for shrimp culture. So, there is an urgent need to developing new studies with the native species, which might represent an alternative concerning shrimp production, with emphasis on Farfantepenaeus subtilis. Another important aspect related to the activity is feeding management, once it is quite usual that feed offer on the pond does not take into account either the species´ physiology and behavior or the influence of environmental variables, such as light cycle and substrate. That knowledge may optimize management and so reduce the impact of effluents in the environment. This study´s objective was characterizing feeding behavior of F. subtilis in laboratory. For that, an ethogram was developed, using 20 wild animals which were observed through ad libitum and all occurrences methods. Two experiments were developed in order to register feeding behavior on different substrates, along 15 days, each. In the first experiment, 40 animals were distributed in eight aquaria, half being observed during the light phase of the 24 hour cycle and the other half in the dark phase, both in halimeda substrate. In the second experiment, 20 animals were distributed in four aquaria, under similar conditions as the previous ones, but in sand substrate. In both experiments, animals were observed respectively one, four, seven and ten hours after the beginning of the phase, for light phase, for the dark phase, in ten minute observation windows, before and immediately after feed offer. The following behaviors were registered: feed ingestion, ingestion of other items, inactivity, exploration, vertical exploration, swimming, crawling, digging, burrowing, and moving by the animals. Observation windows after feed offer also included latency to reach the tray and to ingest feed. Nineteen behaviors were described for the species. F. subtilis presented more behavioral activities in halimeda substrate even in the light phase, while burrowing was predominant in sand substrate. In both substrates, moving, crawling and exploration were more frequent after feed offer, but inactivity and burrowing were more frequent before that. Feed ingestion was more frequent in halimeda, both in light and dark phases. Weight gain was also more prominent in that substrate. In sand substrtate, ingestion was more frequent in the dark phase, which suggests that higher granulometry facilitates feed ingestion in F. subtilis juveniles. Our results demonstrate the importance of studies for the better knowledge of the species, specially its response to environmental stimuli, in order to improve animal management

O papel das rotas e da obtenção de informações sobre a eficiência no forrageio de dinoponera quadriceps em ambiente natural

In this study, we investigated the role of routes and information attainment for the queenless ant species Dinoponera quadriceps foraging efficiency. Two queenless ant colonies were observed in an area of Atlantic secondary Forest at the FLONA-ICMBio of Nisia Floresta, in the state of Rio Grande do Norte, northeastern Brazil, at least once a week. In the first stage of the study, we observed the workers, from leaving until returning to the colony. In the second stage, we introduced a acrylic plate (100 x 30 x 0,8 cm) on a selected entrance of the nest early in the morning before the ants left the nest. All behavioral recordings were done through focal time and all occurence samplings. The recording windows were of 15 minutes with 1 minute interval, and 5 minute intervals between each observation window. Foraging was the main activity when the workers were outside the nest. There was a positive correlation between time outside the nest and distance travelled by the ants. These variables influenced the proportion of resource that was taken to the nest, that is, the bigger its proportion, the longer the time outside and distance travelled during the search. That proportion also influenced the time the worker remained in the nest before a new trip, the bigger the proportion of the item, the shorter was the time in the nest. During all the study, workers showed fidelity to the route and to the sectors in the home range, even when the screen was in the ant´s way, once they deviated and kept the route. The features of foraging concerning time, distance, route and flexibility to go astray by the workers indicate that decisions are made by each individual and are optimal in terms of a cost-benefit relation. The strategy chosen by queenless ants fits the central place foraging and marginal value theorem theories and demonstrate its flexibility to new informations. This indicates that the workers can learn new environmental landmarks to guide their routes

Uso de rotas na área de uso e a relação com comportamento alimentar em Callithrix jacchus

Callithrix jacchus are small primates that live in cooperative reproductive family groups. They explore their home range in search of fruits, exudates and animal prey. In this study we investigate the existence of traveling routes and its relation with the feeding habits in a group of Callithrix jacchus. The group was followed for 6 months in an area of Atlantic secondary Forest at the FLONA-ICMBio of Nísia Floresta, Rio Grande do Norte. Two observers in alternated days collected data referring to the group s location using a GPS navigation device, plotting data in 5 minute intervals, and with a position accuracy under 9 meters. All behavioral recordings were done through focal time samplings. The recording windows were 15 minutes with 1 minute intervals. The main activity was foraging, which propelled the animals to explore the environment with inconsistent intensity through the months, and correlated with the location of fruits, exudates and sleeping sites. From another standpoint, most activities were focused in the core areas that featured most sleeping sites, exudates trees and fruit trees. Insects, mostly Orthopterans, were hunted in all areas. The greater ratio of movement was registered during the last hours of sunlight, when animals returned to the sleeping sites and ate a greater number of fruits. The spatial and seasonal distribution of fruits forced the animals to travel long routes. The capacity to remember the location and navigate efficiently through feeding sources is important to save energy and time costs. Learning and familiarizing with the environment through the use of landmarks and acquisition of new information is extremely important to increase the chances of survival in a constantly changing environment

A influência do status social no forrageio de itens camuflados e avermelhados em sagüis (Callithrix jacchus) cativos

Seeing colors can be advantageous, because they are an important signal for providing information about the environment, such as the location of food. However, not every animals sees these chromatic signals in the same way. In primates, the group of Plathyrrhini has polymorphic sex-linked vision with males always dichromats and dichromats or trichromats females. Studies indicate that trichromats during foraging would benefit by seeing better than dichromats ripe fruits against the green foliage background. On the other hand, dichromats appear to distinguish camouflaged insects better than trichromats. The marmoset (Callihtrix jacchus) is a neotropical primate species that have color vision polymorphism. This species establishes family groups with highly reproductive bias, with breeding females often having preferential access to food. This work aims to study whether the social context influences the foraging ability of camouflaged and red items in groups of C. jacchus. Four groups of captive marmosets were presented to four food tasks, involving difficult, easy, reddish and camouflaged food targets. Foods were presented in a concentrated and dispersed manner, to check whether there was monopolization of the resources by the dominant subjects and if this would affect the ability of individuals to find the food targets. Success was measured by latency to food acquisition and number of targets consumed. Males and females differed in their foraging success for camouflaged and reddish items, although this difference has not appeared in all situations and experimental conditions. In general males were more successful for detecting camouflaged items while females succeeded more in identifying reddish items. There were no differences in foraging success between individuals of different social status, however, there were differences in the success of consumption of food items for different situations when food was concentrate compared with dispersed food. Taken as a role, there was a greater difficulty in detecting food items when they were presented in concentrated arrangement, which is supposed to be related to a higher difficulty to approach and stay near the food. Although it appears that there was no direct competition seems to have group's indirect influence on the detection of food items and foraging success of individuals, affecting mainly those items more difficult to detect

Otimização no uso de martelos e bigornas para quebrar sementes por macacos prego (Cebus flavius e C. libidinosus) no Bioma Caatinga

Recently, capuchin monkeys (Cebus spp.) inhabitants of dry environments and with restriction of fleshy fruits, have been the subject of several studies regarding the use of instruments. During behaviour of using stones to crack open nuts there is evidence of selection of more effective hammers, as well as selection of anvils related to reducing the risk of predation. The aim of this study was to determine whether two groups of capuchin monkeys (C.flavius and and C.libidinosus) inhabitants of the Caatinga of Rio Grande do Norte make choice of hammers and anvils. The record of weight and location of stones indicated active choices of with what (choice of hammers) and where (selection of anvils) to crack open encapsulated seeds. The choice of hammers to break nuts depended on the type and degree of ripeness seed. Thus, smaller seeds were smashed with lighter hammers and larger seeds with heavier hammers. Still, C. flavius was the only species that presented a refinement in the choice of hammers that depended on the ripeness of seeds. For both species of capuchin monkeys studied, the nut-crack sites were not spread in accordance with the spatial distribution of seed-producing species, suggesting that the capuchin monkeys promote active choice of anvils. Thus, in environments with more escape routes through the trees, the nut-crack sites were found further apart than in regions that had less chance of escape through the trees. Also, there was a difference in the spacing of the anvils to depend on the type of seed: sites used to crack larger and more caloric seeds were found farther apart than the sites used to crack smaller and less caloric seeds, suggesting a pattern of avoiding direct competition. We conclude that the capuchin monkeys maximize energy savings and reduced risk of predation and the costs of food competition during the behaviour of using stones to crack open nuts

Sincronização dos ritmos de atividade motora e temperatura central à disponibilidade de glicose em ratos

Food is essential for the survival of all animals. Its temporal availability is an important enviromental cue for the behavioral and physiological organization throughout the 24 hours of day in different species. Rats and mice, for example, show increased locomotion in the hours before food availability when it is presented in a recurrent manner, a behavior named foodanticipatory activity. Several lines of evidence indicate that this anticipation is mediated by a circadian oscillator. In this work, based on the hypothesis that pre- or post-ingestive humoral signals are involved in the entrainment process, we tested whether the daily intake of glucose is sufficient to induce anticipatory activity in rats. The rhythms of motor activity and central temperature were recorded in animals undergoing 10 days of temporal glucose (solution at 50%) or chow restriction in light-dark (LD) and constant darkness (DD). Animals under temporal glucose restriction increase motor activity and and central temperature in the hours preceding glucose availability and such aticipation is extremely similar to that observed in animals under temporal chow restriction. Glucose ingestion is, therefore, a sufficient temporal cue to induce anticipation in rats. It is possible that the increase in plasma glucose after food ingestion constitutes one of the signals involved in the behavioral entrainment process to food availability

O efeito da dessincronização circadiana sobre o metabolismo

The lost of phase relationship between rhythms and behaviour can, and often do, undesirable consequences. The purpose os study was to ascertain the effect of circadian desynchronization in T22 about metabolism of wistar rats. The subjects consisted of 24 animals separated in two groups: control (n=12) T24 with 8 weeks of aged and experimental group (n=12) T22, also with 8 weeks of aged. Both the groups were subject to register of locomotor actitivity, body temperature, body weight and food intake in all the experiment. And more, both the groups were subject to food deprivation, running in treadmill and forced swimming. The results show rhythm of locomotor activity and body temperature desynchronized. Dont exist diference in body weight between both the groups (T24 = 386,75±40,78g e T22 380,83±44,28g) . However, the food intake was different between the phases, light and dark, in intergroup and intragroup. The body temperature was not different in food deprivation. The same ocurred for running in treadmill and forced swimming. Since similar alterations occur in shift workers, it is proposed that the experimental paradigm presented in this manuscript is a useful model of shift work. That is, alterations in activity/rest cycles and consummatory behavior can affect the health of organism

Ontogênese comportamental de Callithix jacchus em ambiente natural

In most primates, the mother is primarily responsible for care in early life of the infants, since, as in other mammals, infants depend on their mother to nutritional conditions. However, unlike most of them, in some species, infants are also dependent on other individuals with respect to transportation, supervision, and food sharing. To understand the distribution of care to offspring is essential to understand the social dynamics of the group. Several studies conducted in the natural environment, during the infant have been studied mainly through the careful transport of the infants. Our study approached the different forms of care to infants (transport, supervision and food sharing) and the development of behavioral repertoire throughout all phases of infant and juvenile seeking to better understand how to establish the development and survival of offspring of Callithrix jacchus, in natural environment. The seasonality in the caatinga was striking in this study and the collection had two distinct seasons for each of the sets observed, one dry and one rainy. These environmental changes seem to have influenced the distribution of activities in animal development. Yet the greater availability of resources in the rainy season seems to have been the main factor influencing the pattern of activities. Results will be presented in two manuscripts

Fatores que influenciam a neofobia alimentar em fêmeas e filhotes de sagüis (Callithrix jacchus)

Considering the constant environmental changes, the ability to introduce new food items in the diet is crucial to omnivore animal survival. For optimal nourishment and lessening of intoxication risks, the animals must detect signs that indicate which items are adequate for their intake. We investigate some factors that interfere in the responses to non familiar food, modulating their neophobic behavior, of marmosets Callithrix jacchus, an omnivore and generalist primate, native to Northeast Brazil, known for being cautious in ingesting not known food. We analyzed the influence of food taste (sweet or salty), pregnancy and sex in feeding behavior and neophobic responses in these animals. 10 captive females were first selected, 5 of them being then pregnant. The females, pregnant or not, ate more when presented to the sweet items than to the salty ones. Pregnant females, however, themselves were less neophobic to both tastes, being also strongly neophilic to the sweets. We verified then the influence of nourishment during pregnancy on young males and females post natal feeding behavior. We observed 10 young divided in two groups, one whose mother ate that food item during pregnancy and one whose mother had no contact to it. In the first group that food was more easily accepted by the young, suggesting that neofobia and feeding behavior had a pre natal influence. Female young also ingested more food and were less neophobic than males, a difference already observed in behavior of adults of these specie. These results suggest that the low neophobic behavior to sweet food showed by females can be adaptive, and might have bestowed more fitness to those who presented it

A influência da recompensa e da experiência na discriminação visual simultânea em sagüi comum (Callithrix jacchus)

The discrimination learning is assessed through instrumental tasks in which the individual is rewarded for choosing one item over another. Thus, in concurrent visual discrimination of objects the animal must learn that only one of the objects will be rewarded. The concurrent visual discrimination is relatively simple, and already been observed Callithrix jacchus is able to accomplish this task. As yet wasn't seen the influence of the qualitative aspects of the rewards, in the performance of concurrent visual discrimination of objects in nonhuman primates, and as in most tests are used isolated animals, the present study had two stages: at first we had as objective to analyze the influence of the caloric value of the reward on the performance in concurrent visual discrimination of objects in isolated animals; in the second, we had the intention analyze performance of C. jacchus in realization of discrimination task in different social contexts, as well as, analyze the influence of previous experience in task performance. In the first stage (Study 1), the animals were not able to discriminate foods that presented small caloric differences . This incapacity in discriminates the rewards was responsible by generating randomness in task of concurrent visual discrimination of objects. In the second stage (Study 2), observed that, independent of social context in which the task was presented, the performance both of the experienced animals as the inexperienced animals tended to randomness. In the first case, is likely that the pattern of responses of the experienced animals is a reflection of their own performance when they were observed in isolation. In the second case, in turn, the randomness was probably due to the small number of sessions. Although present a pattern of performance similar to inexperienced individuals, we verify that the experienced animals monopolize the food consumption when they were in the presence of inexperienced individuals. This was a consequence of the experienced animals have presented lower latency the approximation of apparatus and, consequently, obtain more food. In turn, the inexperienced animals, when were in the presence of experienced, had to adopt alternative strategies to obtain food. Thus, C. jacchus is able to use the previous information he had about the task of solving their own benefit.