WO2005067703A2

WO2005067703A2 - Devices and system for measurement of individual feed intake for laboratory animals

Info

Publication number: WO2005067703A2
Application number: PCT/EP2005/000666
Authority: WO
Inventors: Hans Rasmussen
Original assignee: Hans Rasmussen
Priority date: 2004-01-20
Filing date: 2005-01-20
Publication date: 2005-07-28
Also published as: WO2005067703A8; WO2005067703A3

Abstract

Devices and systems for measuring feed intake of an individual animal living in a group or alone are provided.

Description

Devices and System for Measurement of Individual Feed Intake for Laboratory Animals

Introduction This patent application claims the benefit of priority from U.S. Provisional Patent Application Serial No. 60/537,531, filed January 20, 2004, which is herein incorporated by reference in its entirety.

Background of the Invention Measuring the feed intake of laboratory animals is a common method to assess the influence of agents on the animal. The most common method is to have each animal in its own cage and measure the amount of food that the animal eats, by weighing the food before it is placed in the cage and after the animal finishes feeding. This method assumes that the animal is behaving naturally regarding food consumption. In many cases, this assumption is incorrect. Most laboratory animals live in groups when in nature. It is unlikely that they maintain a natural behavior when isolated in their own cage. As a result, the use of their feed intake as a parameter to measure the influence of agents may not be accurate. In the past, in order to compensate for potentially invalid test results, large numbers of animals have been used. Mechanical feeders have been described which are capable of delivering a set amount of food to an animal over a set period of time. Feeding systems capable of identifying individual animals, usually with the use of a transponder embedded under the animal s skin, and a transponder antenna, near where the food is distributed have also been described. Transponders for identifying an animal and collecting data relating to that animal are described, for example, in U.S. Patent 5,355,833, U.S. Patent 6,067,933, U.S. Patent 6,427,627, U.S. Patent 6,113,539 and U.S. Patent 6,651,585. A feeding device for livestock which automatically supplies a set amount of food over a set amount of time to the livestock has also been described by Voogd et al. in U.S. Patent 6,619,228. The device comprises a feeding parlor, a computer and an animal identification system. This feeding device for livestock controls and/or limits the amount of food given to each individual animal.

Summary of the Invention An object of the present invention is to provide a device for measurement of feed intake of individual laboratory animals. The device can be used to measure feed intake of individual animals living in a group setting or living alone. This feed intake device comprises an entrance chamber with an open front and open rear adjustably sized to permit a single laboratory animal to fit within the entrance chamber. This entrance chamber is equipped with a means, preferably a transponder antenna, which is capable of identifying the laboratory animal when it is in the chamber and transmitting this identification to a computer linked to the device. It is furthermore equipped with a switch which is integrated in the bottom of the entrance chamber. This switch is activated by the animal's forelegs, or any other part of the animal's body touching the switch. The switch is connected to the computer linked to the device as well. A food tray is located adjacent to the open rear of the entrance chamber. In a preferred embodiment, a portion of the bottom of the entrance chamber is mesh and the food tray extends under the entrance chamber below this mesh so that any food dropped by the animal and not ingested during feeding is still accounted for in the weight of the food tray. A movable food dispensing unit is located above the food tray and controls access of the animal to the food tray. The food dispensing unit can moving linearly from a closed position to an open position or circularly with either axial or radial transportation to control filling of the food tray and/or access to the food tray by the animal. The food dispensing unit is also movable to a position beneath the food hopper where it can be filled with food and then moved to re- fill the food tray. Movement of the food dispensing unit is controlled preferably via a motor also linked to the computer. A first weighing means is located -beneath the food tray and measures contents of said rooα tray before, during, and/or after an animal feeds. The first weighing means is also preferably connected to the computer and transmits this weight information thereto. In some embodiments, a second weighing means is placed below the entrance chamber to record the weight of the laboratory animal as it enters and/or exits the feed intake device. It is preferred that this second weighing means also be connected to the computer so that individual animal weights can also be recorded. Another object of the present invention is to provide a system for measuring feed intake of individual animals preferably grouped in the same cage which comprises the above feed intake measuring device and a plurality of transponders for implantation in the animals of the group. This system may further comprise a computer for recordation of animal identity, calculation of feed intake from weight information transmitted by the first weighing means, recordation of individual laboratory animal weight from information transmitted by the second weighing means and/or control of movement of the food dispensing unit.

Description of the Figures Figure 1 shows a diagram of a side view of one embodiment of the feed intake measuring device of the present invention with a linearly movable food dispenser unit in the closed position. Figure 2 shows a diagram of a side view of the same feed intake measuring device of Figure 1 with the linearly movable food dispenser unit in the open position. Figure 3 provides a more detailed view of a linearly movable food dispensing unit of the present invention in the open position with relation to the food hopper and the food tray. Figure 4 provides a detailed view of a circularly movable food dispensing unit with axial transportation which controls access to the food tray by the animal. Figure 5 provides a detailed view of a circularly movable food dispensing unit with radial transportation which controls access to the food tray by the animal. Detailed Description of the Invention The present invention provides devices and systems for measuring the amount of food taken in by an individual laboratory animal. Unlike the prior art, the present invention measures amount of food taken, and does not define a set amount of feed given to an animal. These devices can be used to measure feed intake in individual laboratory animals caged with a group of animals or living individually. A preferred arrangement for elements of this feed intake measuring device is depicted in Figures 1-2. The embodiment depicted in Figures 1-2 is shown with a linearly movable food dispensing unit. In the simplest form, as shown in Figures 1 and 2, the device of the present invention comprises an entrance chamber 4 equipped with a transponder antenna 6 capable of identifying an animal implanted with a transponder and a switch 9 integrated in the bottom 4c of the entrance chamber 4 that can be activated by the animal, a food tray 3 located adjacent to the entrance chamber 4, a movable food dispensing unit 5 positioned above the food tray 3, a platform 8 located beneath the food dispensing unit 5, a motor 7 for movement of the food dispensing unit 5, a first weighing means 1 located beneath the food tray 3, and a food hopper 2 for storage of excess feed. In the feed intake measuring device of the present invention, an animal enters the device through an open front 4a of the entrance chamber 4. The entrance chamber 4 is preferably adjustably sized in accordance with the size of the animals being caged so that entry is limited to a single animal at one time. Animals using the device of the present invention have embedded under their skin a transponder so that the identity of the animal can be recorded when it is in the entrance chamber 4 via the transponder antenna 6 located at the open front 4a of the entrance chamber 4. Methods for implanting and/or embedding transponders in animals, and their general use, are well known in the art . As will be understood by those of skill in the art upon reading this disclosure, embodiments of this device of the present invention used to measure feed intake in individually caged animals need not contain the transponder antennae nor is it required that the animal be implanted with a transponder.

A switch is integrated into the bottom of the entrance chamber. This switch is activated by touching by a body part of the animal in the chamber. The switch is linked to a computer linked to the device as well and its activation is required for appropriate feeding of the animal in the entrance chamber . To obtain ood the animal must proceed through the entrance chamber to the open rear 4b of the entrance chamber 4 where a food tray 3 is located adjacent to the open rear 4b of the entrance chamber 4. In a preferred embodiment, the food tray preferably extends beneath at least a portion of the bottom of the entrance chamber 4c. In this embodiment, it is preferred that at Least a portion of the bottom of the entrance chamber closest to the open rear be comprised of mesh so that any food dropped by the animal while eating falls back into the food tray. This embodiment provides more accurate information regarding feed intake as wasted food not ingested is accounted for. It is preferred that the food tray only extend under a portion of the entrance chamber so that animal waste, namely feces and urine, do not fall into the food tray as well. The food tray 3 has an open top 3a for access to food and a closed bottom 3b to hold or retain food in the food tray 3. A first weighing means 1 is located beneath the food tray

3 and records weight of any food in the food tray 3 before, during and/or after: feeding of an animal. Recorded weights are preferably transmitted by the first weighing means 1 to a computer linked to the weighing means 1. Access by the animal to the food tray 3 is controlled by a movable food dispensing unit 5 positioned parallel to the food tray 3, between the food tray 3 and the entrance chamber 4. Various configurations for movable food dispensing units can be used. For example, in one embodiment, as shown in Figures 1—3, wherein the food dispensing unit moves linearly, the food dispensing unit 5 comprises a solid rectangle portion 5a with a open region 5b extending through the food dispensing unit near the center of the solid rectangle portion 5a. As shown in Figure 1 and 2, the solid rectangle portion 5a of the movable food dispensing unit 5 is sized to extend from beneath the entrance chamber 4 to beneath a food hopper 2, which is adjacent to the food tray 3. The open region 5b of the food dispensing unit 5 is sized to permit access by the animal to the food tray 3 when positioned directly above the food tray 3. This open region 5b, in combination with a platform 8, also serves as a means for re-filling the food tray with food stored in the food hopper 2. The movable food dispenser unit 5 has multiple positions, including a closed position as depicted in Figure 1 wherein access of the animal to the food tray 3 is blocked by the solid rectangle portion 5a of the food dispensing unit 5 acting as a cover over the food tray 3, an open position as depicted in Figure 2 wherein the open region 5b of the food dispensing unit 5 is positioned above the food tray 3 so that the animal has access to food in the food tray 3, and a filling position wherein the open region 5b of the movable food dispensing unit 5 is placed beneath the food hopper 2. A more detailed view of the linearly movable food dispensing unit of the present invention in the open position with relation to the food hopper and the food tray is depicted in Figure 3. As shown in this Figure, the linearly movable food dispensing unit may further comprise sides 5c and 5d extending perpendicularly with respect to the solid rectangular portion 5a and the open region 5b of the movable food dispensing unit. As shown in Figure 3, these sides 5c and 5d preferably extend over the food dispensing unit from the rectangular portion of the food dispensing unit residing beneath the food hopper through at least the open region of the food dispensing unit. These sides 5c and 5d assist in containing food during refilling. Movement of the food dispensing unit 5 is controlled by a motor 7 integrally linked to the food dispensing unit. A shown in Figure 1 and 2, the linearly movable food dispensing unit 5, slides between its open, closed and filling positions over a platform 8 located parallel to the food dispensing unit 5 and between the food dispensing unit 5 and the food tray 3. Like the movable food dispensing unit 5, this platform 8 also comprises a solid rectangular portion 8a and an open region 8b and extends from beneath the entrance chamber 4 to beneath the food hopper 2. Unlike the movable food dispensing unit 5, however, the platform 8 is fixed so that the open region 8b remains above the food tray. Thus, when the food dispensing unit 5 is in the open position, the open region 5b of the food dispensing unit 5 aligns with the open region 8b of the platform 8, allowing access by the animal to the food tray 3 below (see Figure 2) . As shown in Figures 1 and 2, a food hopper 2 is positioned adjacent to the food tray 3 above the food dispensing unit 5. The food hopper 2 remains closed by the solid rectangle portion 5a of the food dispensing unit 5 when in its open and closed positions. When in its refilling position, food from the food hopper 2 moves from the food hopper 2 via gravity into the open region 5b of the food dispensing unit 5, which in that position is sealed via the solid rectangle portion 8a of the platform 8. When the food dispensing unit 5 is moved to the open position, food in the open region 5b falls through the platform's open region 8b into the food tray 3. In a preferred embodiment, the transponder antenna transmits the identity of the animal to a computer when the animal is in the entrance chamber. It can then be determined whether or not the animal is to be fed, for example, based upon its prior feeding. If the animal is to be fed, and the animal has activated the switch which is an integrated part of the bottom of the entrance chamber, the computer transmits this information to the motor which then moves the food dispensing unit to the open position, exposing the food tray. When the animal is moving away from the food tray and no longer activates the switch integrated in the bottom of the entrance chamber, this information is transmitted to the computer, and then to the motor, which then moves the food dispensing unit back to the closed position. Thus, the food dispensing unit preferably automatically resets to the closed position after each feeding, and is only reopened when given a command from a computer. Weight of the food tray is determined by the first weighing means and this information is also preferably transmitted to the computer. Weight prior to consumption of food in the tray and following consumption of food in the tray are transmitted to the computer via the first weighing means. In some embodiments, the computer can be programmed to move the food dispensing unit into a closed position prior to exiting of the animal from the entrance chamber based upon a set amount of food consumption. When the amount of food in the food tray falls to a predetermined amount, the motor moves the food dispensing unit to its filling position under the food hopper. The volume of the area exposed by the open region 5b of the food dispensing unit, beneath the food hopper determines the amount of feed transferred from the hopper to the open region and ultimately to the food tray. The platform 8 beneath the open region of the food dispensing unit acts like a bottom, holding the food within the food dispensing unit. Once filled, the motor then moves the entire food dispenser unit back to the open position above the food tray so that the feed is released into the food tray. Alternative embodiments of movable food dispensing units in relation to the food hopper and food tray are depicted in Figures 4 and 5. These embodiments move circularly either axially (see Figure 4) or radially (see Figure 5) . In the axially movable food dispensing unit, the food tray and food hopper are in fixed positions beneath and above, respectively, the food dispensing unit. Figure 4 shows the axially movable food dispensing unit in a closed position with respect to the food tray and food hopper. When turned 120° clockwise, the opening in the food dispensing unit is beneath the food hopper in a filling position. The food dispensing unit can be filled with food. The axially movable food dispensing unit can then be moved counterclockwise to a position above the food tray so that food in the food dispensing unit falls into the food tray. In the radially movable food dispensing unit, depicted in Figure 5, the food tray and food hopper are again in fixed positions beneath and above, respectively, the food dispensing unit which rotates along a horizontal axis. In this embodiment, there is slot at the bottom of the food hopper so that when the movable food dispensing unit is rotated up so that the opening in the movable food dispensing unit is aligned with the slot, food falls into the movable food dispensing unit. When the movable food dispensing unit is rotated down so that the opening is above the food tray, the food falls out into the food tray. In a preferred embodiment, the feed intake device of the present invention further comprises a second weighing means placed beneath the entrance chamber which records the weight of the laboratory animal as it enters and/or exits the feed intake device. It is preferred that this second weighing means also be connected to the computer so that individual animal weights can also be recorded. The advantage to the device of the present invention over prior art is that the food dispenser unit allows the device to transport a well defined amount of food from the food hopper, to the food tray. Further, in some embodiments, access to the food tray by a feeding animal is also controlled, all in one movement. While the present invention can be used to measure feed intake in individually caged laboratory animals, the device is particularly useful in a laboratory setting to monitor feed intake of individual animals grouped together in a cage. Traditionally, each animal had its own cage, and feeding was monitored by manually weighing the food tray before and after feeding. However, it is believed that the single animal s feeding behavior in an individual lab cage may not emulate natural feeding behaviors. To compensate for that possibility, large numbers of animals have been used in the past. The present invention allows animals to be placed as a group in a cage, presenting a more natural environment, while still providing a means to measure an individual animal's consumption. The present invention also relates to systems comprising the above described feed intake measuring device and a plurality of transponders for implantation into animals. The systems- of the present invention may further comprise a computer for collection of information relating to animals' identities, their food consumption and for control of movement of the food dispensing unit.

Claims

What is claimed is :

1. A device for measuring feed intake of an individual animal comprising: a) an entrance chamber having an open front and an open rear and a bottom; b) a switch integrated into the bottom of the entrance chamber which can be activated by an animal in the entrance chamber; c) a transponder antenna located so it will detect an animal in the entrance chamber, said transponder antennae capable of transmitting information to a computer regarding identity of an animal entering and exiting the entrance chamber; d) a food tray located adjacent to the open rear of the entrance chamber; e) a weighing means located beneath the food tray which measures weight of the food tray before, during or after an animal feeds; f) a movable food dispensing unit positioned between the food tray and a food hopper; g) a food hopper located adjacent to or above said food tray and above the movable food dispensing unit which holds excess food; and h) a motor linked to the movable food dispensing unit capable of moving said movable food dispensing unit between the food tray and the food hopper to re-fill the food tray.

2. The device of claim 1 further comprising a computer which collects information transmitted from the switch integrated in the bottom of the entrance chamber, the transponder antennae and the weighing means and controls movement of the food dispensing unit via the motor.

3. The device of claim 1 wherein said movable food dispensing unit moves linearly with respect to the device and comprises a solid rectangle portion with an open region extending through the movable food dispensing unit near the center of the solid rectangle portion sized to permit access by the animal to the food tray when positioned directly above the food tray.

4. The device of claim 1 wherein said movable food dispensing unit moves circularly with respect to the device via axial transportation to control filling of the food tray from excess food in the food hopper.

5. The device of claim 1 wherein said movable food dispensing unit moves circularly with respect to the device via radial transportation to control filling of the food tray from excess food in the food hopper.

6. The device of claim 1 further comprising a second weighing means beneath the entrance chamber to record animal weight upon entry or exit of an animal.

7. The device of claim 1 wherein the entrance chamber comprises a bottom mesh portion and the food tray extends under the entrance chamber beneath this bottom mesh portion to catch any food dropped by an animal feeding in the entrance chamber.

8. A system for measuring feed intake of an individual animal comprising the device of claim 1 and a plurality of transponders for implantation into animals.

9. The system of claim 8 further comprising a computer which collects information transmitted from the switch integrated in the bottom of the entrance chamber, the transponder antennae and the weighing means and controls movement of the food dispensing unit via the motor.