FR3062783A1 - DEVICE FOR STUDYING ANIMAL BEHAVIOR. - Google Patents

Abstract

A device for studying animal behavior (S) comprises: at least one chamber (10) for receiving an animal (S), the chamber (10) has a plurality of doors (11), the device having an access station for accessing a supply device (12) behind each door (11) from said chamber (10), and motorization means for operating each door (11) in opening and closing, control means (2) arranged to maneuver the opening of the doors (11) according to a predetermined cycle.

Description

Holder (s): UNIVERSITY OF BOURGOGNE, HIGHER NATIONAL INSTITUTE OF AGRICULTURAL SCIENCES OF FOOD AND THE ENVIRONMENT, INSERM.

Extension request (s)

Agent (s): OFFICE FREYLINGER.

104 / DEVICE FOR THE STUDY OF ANIMAL BEHAVIOR.

FR 3 062 783 - A1 (5 /) A device for studying animal behavior (S) comprises:

? at least one room (10) for receiving an animal (S),? the chamber (10) has a plurality of doors (11), the device comprising an access station for accessing a supply device (12) behind each door (11) from said chamber (10), and? motorization means for operating each door (11) during opening and closing,? control means (2) arranged to operate the opening of the doors (11) according to a predetermined cycle.

DEVICE FOR THE STUDY OF ANIMAL BEHAVIOR

FIELD OF THE INVENTION

The invention relates to a device for studying animal behavior, in particular for studying taste. It also relates to a method for studying animal behavior using this device.

PRIOR ART

The purpose of the devices for studying animal behavior for nutrition is to explore different characteristics of behavior with, among other things, the immediate satisfaction brought by a food relative to other foods, the learning capacities to find it and the determination to obtain this food. Research studies distinguish these components, with an affective component called "liking" which corresponds to the immediate pleasure in consuming a food, a motivational component called "wanting", which corresponds to the determination to obtain the expected food reward, and the cognitive component. so-called “learning”, which corresponds to the ability to memorize previous eating experiences allowing a hierarchy of the hedonic valence of food.

Such behavioral studies are frequently conducted in laboratory rodents, such as rats or mice. Equipment is used which makes it possible to present food in solid or liquid form in a controlled manner and to measure certain elements of behavior.

For example, document EP 2 246 799 A1 shows a device comprising a chamber for receiving an animal. From the bedroom, the animal has access to water bottles and a basket for solid food. The device is equipped with an image acquisition and analysis system to characterize the behavior of the animal. The bottles and the basket are equipped with sensors to provide signals when the animal accesses them.

There is also known a device for testing the taste of food sold under the reference DAVIS MS 160 by Dilog Instruments. This device has different bottles containing liquid food, for example with different concentrations, parading in front of a door. When the door is opened, the animal’s behavior is measured by detecting licks on the bottle nipple. We measure the delay after opening the door, frequency and number, for example. We thus assess the affective comio of the behavior induced by the food presented. However, this device has the disadvantage of presenting the food always in the same place. As a result, the animal is not active, it just stays in the same place to access food. Thus, parameters of its state escape observation.

i5 Document WO 2010/144494 A1 shows a housing system for animal experimentation in which a central cage is provided on various walls with stations for distributing food in solid form. The system is modular and the central cage can be extended by tunnels leading to other cages or stations of different functions.

Document EP 2 859 889 A1 shows the use of a cage for square-shaped mice, the four corners of which are provided with food distribution stations. The stations are equipped with normally closed doors which open on the action of the mouse placed in the cage. Such a cage allows for example to implement a shuttle protocol.

According to this protocol, two stations have their doors closed and inactive, while two other stations have their doors active alternately, i.e. a door which has just closed will only open after the door of the second station has been activated. This material and this protocol make it possible to study the cognitive component of mouse behavior.

OBJECTIVES OF THE INVENTION

To solve these problems, the invention aims to provide a device making it possible to explore the affective, motivational, and learning components of an animal.

DESCRIPTION OF THE INVENTION

With these objectives in view, the invention relates to a device for the study of animal behavior comprising:

io> at least one room for receiving an animal,> the room has a plurality of doors, the device comprising an access station for accessing a supply device behind each door from said room, and> motorization means for operate each door in opening i5 and in closing, characterized in that it further comprises control means arranged to operate the opening of the doors according to a predetermined cycle chosen randomly from a collection of cycles.

With the invention, we have the means to carry out an experimentation with animal behavior in a more detailed manner than according to the prior art. We can for example present a different food behind each door and open one by one the doors behind which there is a food, in a predetermined order that is not regular or expected. For each door opening, the quantification of the animal's interest in the food makes it possible to assess the attractiveness of this food for the animal. The animal must move from door to door, which makes it possible to perceive additional behavioral indications important for the comparative phenotyping of animals: state of stress, motivation. The order of presentation of food is perceived by the animal as random, which eliminates from the test a conditioning character in order to assess the affective component of the behavior. You can vary the nature of the food in the same test or the concentration of the same food or substance. The drawing of successive cycles in the cycle collection allows you to vary the order of opening the doors from one cycle to the next so as not to interfere with learning the animal. Each cycle is developed by ensuring that it respects certain rules, such as the number of openings of each door in the cycle, this number may be zero, or the repetitions of openings possible or not. The cycle can be previously determined and stored, or alternatively calculated with a random factor on demand just before its implementation. The collection of cycles is then formed by the finite set of possible arrangements respecting the rules used.

Preferably, the predetermined cycle includes an opening and a single i5 of each door.

According to an advantageous arrangement, the feeding device comprises a reservoir provided with a teat for supplying a liquid to the animal, the teat comprising detection means for detecting that the animal is fed by said teat. We can thus quantify the number of laps of the animal, and therefore the appreciation of the food by the animal, the greater the number of laps, the greater the interest of the animal for the food. The presentation in liquid form also makes it possible to specifically study the perceived taste of the food. It also makes it possible to easily vary the concentration with a more or less diluted substance.

According to an improvement, the detection means are capable of providing a signal for each lick of the animal. This allows you to closely monitor the amount of liquid absorbed by the animal, in total and quickly. One of the preferred means for this measurement is the detection of the closing of an electrical circuit between the teat and the animal, thanks in addition to a conductive grid serving as a floor for the chamber.

According to an advantageous arrangement, the control means are arranged to control the closing of the open door after a predetermined period depending on the moment when the detection means have detected that the animal is feeding. Thus, the door remains open until the animal has come to bed. This allows, by measuring the time between the opening of the door and access to the food, to assess the motivation and learning of the animal.

According to an additional provision, the opening of a next door according to the predetermined cycle is ordered at the end of a predetermined period following the moment when the previous door was closed.

io According to a constructive arrangement, the doors are slidably mounted vertically by opening upwards. This optimizes the lateral dimensions of a door.

According to another constructive arrangement, the top of the chamber is closed by a cover pierced by at least one orifice. The animal cannot escape is but the ventilation of the room is ensured by this orifice. The cover can also be removable to allow easy access to the animals for the experimenter.

In addition, the device includes a ventilation system to evacuate odors.

According to a constructive arrangement, the access station comprises a removable tunnel between the door and the supply device. The device is thus distant from the chamber. We can thus assess the motivational component of the animal for access to food.

According to an improvement, the device includes measuring means for measuring the journey time of the animal from the start of a test until the animal has reached the feeding device.

The subject of the invention is also a method of studying animal behavior with a device comprising at least one chamber,> the chamber comprising a plurality of doors,> the device comprising an access station for accessing a feeding device behind each door from said chamber, and> motorization means for operating each door during opening and closing, process according to which a food is supplied in each feeding device, the animal is placed in the room, characterized in that the doors are opened according to a predetermined cycle chosen randomly from a collection of cycles and the quantity of each food taken by the animal is observed.

In particular, a food is provided in liquid form, the concentration in the liquid of a sapid substance to be evaluated being different between each feeding device.

In particular, the instant at which the animal begins to absorb the food accessible by an open door is detected and said open door is closed after a predetermined period following said instant.

In particular, one of the doors is opened according to the predetermined cycle after a predetermined period following the closing of the previous door.

The invention will be better understood in the light of the embodiments, the detailed description of which will follow, illustrated by the drawings among which:

> Figure 1 is a perspective view of a device according to a first embodiment of the invention, with an enlargement of detail I in Figures la and lb in two different positions;

> Figure 2 is a schematic top view of the device of Figure 1;

> Figure 3 is a time diagram of the opening of the doors of the device of Figure 1;

> Figures 4 and 5 are schematic top views of the device according to other modes of use;

> Figure 6 is a graph plotting the number of sucks as a function of a concentration of sucrose solutions, for two different populations of mice;

> Figures 7 and 8 are histograms respectively showing the number of sucks and the number of cycles for each of the mouse populations.

DETAILED DESCRIPTION

A device 1 for studying animal behavior according to the invention is shown in FIGS. 1, 1a and 1b. It comprises a chamber 10 for receiving an animal S delimited by eight doors 11 with vertical leaves 110 distributed in a regular octagonal plane, a metal grid 14 in the floor and a cover 16 is pierced by a plurality of orifices, not shown, in the ceiling . Each leaf 110 of door 11 is mounted to slide vertically in slides 111 and comprises a door orifice 112. The study device 1 further comprises behind each door 11 a supply device 12 comprising a support 120 for supporting a tank under bottle shape 121 in an inclined position. Each bottle 13 has a teat 122 oriented downwards and towards the door 11.

Each leaf 110 struggles between two positions, an open position in which the door orifice 112 of door 11 is opposite the teat 122, like the leaf identified 110a, and a closed position in which the orifice 112 is below the level of the grid 14, like the leaf identified 110b. The leaf 110 is driven by motorization means, not shown, on command between the open position and the closed position.

The device also comprises control means 2 which control the motorization means. These control means typically include a programmable microcontroller, not shown, the operation of which is not detailed here.

The control means 2 are further connected to each of the teats in order to detect each lap of the animal S. The detection is carried out by the establishment of an electrical circuit of very low intensity between the animal S, connected to the mass by the grid 14, and the nipple 122. Such a detection means is known by the name of "lickometer" in English.

With this embodiment of the device 1, experiments were carried out according to the protocol which will be described. The protocol was based on that which was developed by Glendinning et al. (Chem. Senses 2002, 27: 461-474). The device was placed in a ventilated enclosure 3 to eliminate odors and acoustically isolated to limit disturbances.

The animals S undergo three learning phases which aim to reduce their contextual neophobia (knowledge of the device: environment, door noises) and to understand the course of the test.

Training 1: knowledge of the environment

The animal S such as a mouse or a rat is placed in the study device 1 for the first time, after a water deprivation of 9:30 pm, as shown in FIG. 2. The eight leaves 110 are in the open position, allowing unlimited access to all 121 bottles containing water, for 30 min from the first lick. Animal S becomes familiar with this new environment and, being thirsty, associates it with a reward (free access to water). At the end of the test, the control means 2 control the closing of the leaves. Animal S is returned to its original cage and has access to a bottle of ad libitum water for 1:30. This will allow animals that have not fully quenched their thirst to drink before another deprivation period. They are then placed in water restriction again for stage 2.

Training 2: learning the protocol

After another water deprivation of 9:30 p.m., the animals S are again placed one by one in the study device 1. This second training corresponds to the real situation of the test with the difference that the eight bottles 121 contain only water. Referring to Figure 3, at time tO, the control means 2 control the opening of a first of the leaves 110. The door 11 remains open until the rodent has lapped. From the first lap, at time tl, a predetermined delay of 10 seconds elapses before door 11 closes again at time tl + lOs: these first 10 seconds correspond to a test. This very short test duration makes it possible to limit the behavior observed (number of laps) to the only orosensory component. After the expiration of a predetermined time of 10s since the closing of the previous door 11, therefore at tl + 20s, the control means 2 control the opening of a door 11. The door remains open as long as the animal does not come to eat. From the first lap, at time t2, the control means 2 begin i5 to count down again a predetermined delay of 10 seconds. The training stops 30 minutes after the first try. The order of opening doors 11 at each cycle is chosen randomly by computer draw. In each cycle, all the doors 11 open once and only once. An experiment comprises a number of cycles not predetermined in advance, which is a function of the response time of the animal to taste the solution proposed behind each door. At the end of this training, the animal S is replaced in its cage, containing water and food ad libitum for 2 to 3 days.

The order to open the doors 11 is carried out according to a succession of predetermined cycles chosen randomly from a collection of cycles. The cycles are predetermined so that in the cycle, all the doors 11 open once and only once.

Training 3: reinforcement

After this time of rest, the food and the water are withdrawn from the cage of the animal S during 21:30. This last learning phase, which is carried out with a very attractive sapid molecule (sucrose), aims to reinforce the exploratory behavior of animals in the device by motivating them with a taste reward. This training also makes it possible to verify that the protocol does not inflict excessive deprivation on rodents. In fact, we will have to observe an increase in the number of laps depending on the sucrose concentration of the 121 bottles and not according to their order of appearance.

Experimentation

The experiment focused on the comparison of two groups of S animals, one comprising thin animals, the other comprising obese animals. io After each animal S has followed the three training phases, they have followed an exercise with a strong gustatory stimulus. This exercise was carried out with 8 121 bottles containing 0; 0.01; 0.03; 0.06; 0.1; 0.2; 0.3; and 0.6 M sucrose, diluted in water. These solutions were randomly placed in the device. The sequence of training 3 has been implemented. We measured the number of lapsed per bottle 121 and the number of cycles for each animal S. The results are presented in FIGS. 5 to 7.

Figure 5 has two curves, the std curve for thin animals and the hf curve for obese animals. They represent the number of laps per animal S as a function of the concentration of the sucrose solutions. There is a growing interest in the higher concentrations for the two populations, but at a lower level for obese animals.

Indeed, it has recently been shown that obesity is accompanied by a drop in taste detection of sugars, and therefore of the affective component. In accordance with the literature (Shin et al. Am J Physiol 2011, 301: R1267-80), we note:

1. that the number of laps is higher the higher the sugar content, regardless of the group of mice studied (thin or obese animals), and

2. that the number of laps is systematically lower in obese mice than in control animals.

In another use of the device, shown in FIG. 4, a tunnel 15 is interposed behind one of the doors 11 of the device before the supply device. The purpose of this configuration is to measure the motivational component of eating behavior. The chamber 10 corresponds to the place of departure of the test, closed by the door 11, the opening of which is controlled by the control means 2. The tunnel 15 allows the animal S to reach the feeding device more or less quickly 12 which contains a food reward.

io Rodents are first placed in the apparatus during two 10 min sessions in order to accustom them to the environmental context. This habituation continues with two additional sessions during which the animals have access to the reward in the feeding device 12. This second step will allow to continue to decrease the contextual neophobia but i5 will also allow to decrease the food neophobia (chosen reward ). The test starts from the opening of door 11 giving access to tunnel 15 and ends when animal S has found the reward or after 10 minutes of testing. The behavior of animal S is recorded by means of a camera and is analyzed by tracking software. We measure in particular the time it takes the rodent to get out of room 10 and the time it takes to access the reward. These values could also be measured with other means such as photocells or infrared sensors.

In another configuration, illustrated in Figure 5, the goal is to measure the cognitive component of eating behavior. It is based on the principle of the labyrinth. The control means 2 are connected to a movement analysis system, not shown, comprising at least one camera and analysis software making it possible to characterize the movements of the animal

S. In this configuration, the octagonal chamber 10 is extended behind the doors 11 by eight tunnels 15 ”of transparent synthetic material such as transparent polymethyl methacrylate and several visual cues are placed around the system. Among the eight 15 ”tunnels, four have a reward (palatable food) at their end in the feeding device 12. The animal S follows a protocol, based on that of ValladolidAcebes et al. (Neurobiology of learning and memory 2011, 95, 80-85) consisting of several phases:

> an habituation phase during which he can move freely in the labyrinth for 10 min,> an acquisition phase of two consecutive trials (5 min each) during eight consecutive days where the animal S will have access to the four awards , io> a retention phase which consists of a test of 5 min, 2, 3, 4, 5 and 6 days after the end of the acquisition sessions.

The behavior of animal S is recorded by means of a camera and is analyzed by the analysis software. In particular, we count the number of errors of animal S, translated by entries into 15 ”tunnels where the food has already been eaten or which did not include a reward.

Claims (14)

Claims 1. Device for the study of animal behavior (S) comprising: > at least one room (10) for receiving an animal (S),> the room (10) has a plurality of doors (11), the device 5 comprising an access station for accessing a supply device (12) behind each door (11) from said chamber (10), and> motorization means for operating each door (11) during opening and closing, characterized in that it further comprises control means (2) io arranged to maneuver the opening of the doors (11) according to a predetermined cycle chosen randomly from a collection of cycles. 2. Device according to claim 1, wherein the predetermined cycle comprises an opening and only one of each door. 3. Device according to claim 1 or 2, wherein the feed device (12) comprises a reservoir (121) provided with a teat (122) for supplying a liquid to the animal (S), the teat ( 122) comprising detection means for detecting that the animal (S) feeds on said teat (122). 4. Device according to claim 3, according to which the detection means 20 are capable of providing a signal for each lick of the animal (S). 5. Device according to claim 3 or 4, wherein the control means (2) are arranged to control the closing of the door (11) opened after a predetermined period depending on the time when the means of 25 detection detected that the animal (S) is feeding. 6. Device according to one of the preceding claims, according to which the opening of a next door (11) according to the predetermined cycle is controlled after a predetermined period following the instant when the previous door (11) has been closed. 7. Device according to one of the preceding claims, in which the doors (11) are slidably mounted vertically by opening upwards. 8. Device according to one of the preceding claims, in which the top of the chamber (10) is closed by a cover (16) pierced by at least one orifice. 9. Device according to one of the preceding claims, in which the access station comprises a removable tunnel (15) between the door (11) and the supply device (12). 10. Device according to claim 9, characterized in that it comprises io measuring means for measuring the travel time of the animal (S) from the start of a test until the animal (S ) has reached the feed device (12). 11. Method for studying animal behavior (S) with a device comprising at least one chamber (10), i5> the chamber (10) comprising a plurality of doors (11),> the device comprising an access station for access a supply device (12) behind each door (11) from said chamber (10), and> motor means for operating each door (11) in 20 opening and closing, process according to which the animal (S) is placed in the chamber (10), a food is provided in each feeding device (12), characterized in that the opening of the doors is operated (11) according to a predetermined cycle chosen randomly from a collection of cycles and the quantity is observed 25 of each food taken by the animal (S). 12. The method of claim 11, according to which a food is provided in liquid form, the concentration in the liquid of a sapid substance to be evaluated being different between each feeding device (12). 13. Method according to one of claims 11 or 12, according to which one detects 30 the instant at which the animal (S) begins to absorb the food accessible by an open door (11) and said open door (11) is closed after a predetermined delay following said instant. 14. Method according to one of claims 11 to 13, according to which one of the doors (11) is opened according to the predetermined cycle after a predetermined time after the closing of the previous door (11). 1/3