1 ORAL-FEEDING DEVICE This invention relates to an oral-feeding device, more particularly to an oral-feeding device that delivers a flowable material such as food or medicine into a mouth of 5 an animal that is relatively small in size. When feeding a pet or a laboratory animal that is relatively small in size, it is relatively difficult to successfully deliver a desired amount of food or medicine into the mouth of the animal. Especially when the animal 10 has a loss of appetite or suffers from sickness, the animal may refuse to eat, which makes the feeding process even more difficult. Under such circumstances, an aiding tool, such as a chopstick, may have to be used to force the mouth of the animal to open for delivery of the food or medicine. 15 This force-feeding process is not only effortful but also time-consuming. In addition, tracheas of some animals such as reptiles are located above the rear ends of their tongues, so that when a conventional syringe, which includes a barrel and a plunger, is used for feeding a reptile, the food or 20 medicine may accidently flow into the trachea of the reptile and may result in asphyxia if the plunger of the syringe is pushed too rapidly. Referring to FIG. 1, a conventional oral-feeding device is shown to include a feeding tube 4 that defines a passage 25 43 having opposite front and rear open ends 431, 432, and a connecting member 42 that is connected to the rear open end 432 of the passage 43 and that is integrally formed with 1001214992 2 the feeding tube 4. The feeding tube 4 includes a ball-shaped insert end portion 41 having the front open end 431. Prior to feeding, the conventional oral-feeding device is connected to a syringe (not shown) filled with a food. 5 When in use, a user holds the syringe and makes the insert end portion 41 of the feeding tube 4 abut against the mouth of the animal, and then exerts a force so as to permit entry of a portion of the feeding tube 4 into the mouth. Once the insert end portion 41 is brought to pass past the trachea 10 and inserted into the oesophagus of the animal, the user can then push the plunger of the syringe to allow the food to flow out from the front open end 431 and into the oesophagus, thereby preventing the food from accidently entering the trachea of the animal. However, if the animal 15 to be fed has an oral organ that is hard and stiff, e.g., beak of a bird, it is still difficult to manipulate the insert end portion 41 of the feeding tube 4 into the mouth of the animal since the insert end portion 41 is ball-shaped. The user may still have to rely on an aiding tool, such as 20 a slab, to pry open the mouth of the animal prior to feeding using the conventional oral-feeding device. Therefore, an object of the disclosure is to provide an oral-feeding device that facilitates delivery of food or medicine into a mouth of an animal without the need of 25 using an aiding tool. According to the disclosure, the oral-feeding device is adapted for delivering a flowable material into a mouth of 1001214992 3 an animal that is located in front of the oral-feeding device. The oral-feeding device includes a hollow feeding tube. The feeding tube includes a main tubular portion and a flat portion. The main tubular portion defines a passage 5 that is adapted for delivering the flowable material and that has an outlet located at a front end of the main tubular portion. The flat portion extends forwardly from the front end of the main tubular portion, receives the flowable material from the outlet, and is adapted to be inserted into 10 the mouth of the animal for delivering the flowable material flowing out of the outlet. Other features and advantages of the disclosure will become apparent in the following detailed description of the embodiment with reference to the accompanying drawings, 15 of which: FIG. 1 is a perspective view of a conventional oral-feeding device; FIG. 2 is a perspective view of an embodiment of an oral-feeding device according to the disclosure; 20 FIG. 3 is a sectional side view of the embodiment; FIG. 4 is a perspective view illustrating the embodiment connected to a delivering device; and FIG. 5 is a schematic view illustrating how the embodiment is used to feed an animal. 25 Referring to FIGS. 2 to 3, an embodiment of an oral-feeding device according to the disclosure is adapted for delivering a flowable material 5 into a mouth of an 1001214992 4 animal such as a turtle 6 (see FIG. 5) that is located in front of the oral-feeding device. The flowable material 5 is, for example and not limited to, food or medicine in the form of liquid, slurry, gel or powder suspension. The 5 oral-feeding device includes a hollow feeding tube 1 and a connecting member 2. The hollow feeding tube 1 extends along an axis (L), and includes a main tubular portion 10 and a flat portion 11. The main tubular portion 10 has an annular cross section, 10 surrounds the axis (L), and defines a passage 101. The passage 101 is adapted for delivering the flowable material 5, and has opposite inlet 102 and outlet 103. The inlet 102 is located at a rear end of the main tubular portion 10. The outlet 103 is located at a front end of the main tubular 15 portion 10. The front end of the main tubular portion 10 has an inclined end surface 104 that is formed with the outlet 103. The inclined end surface 104 has a higher rear end 105, and a lower front end 106 that is below the higher rear end 105. The flat portion 11 of the feeding tube 1 20 extends forwardly and upwardly from the lower front end 106 of the inclined end surface 104, and has an arc-shaped front edge. The flat portion 11 has a receiving surface 111 for receiving the flowable material 5 from the outlet 103, and is adapted to be inserted into the mouth of the animal for 25 delivering the flowable material 5 flowing out of the outlet 103. In greater detail, the receiving surface 111 of the flat portion 11 forms an obtuse angle with the inclined end 1001214992 5 surface 104 of the main tubular portion 10. It should be noted that the main tubular portion 10 of the feeding tube 1 is straight in the embodiment. Alternatively, in other variations of the embodiment, the 5 main tubular portion 10 may be configured to have different shape depending on the size or the anatomical structure of the mouth and throat of the animal. For example, the main tubular portion 10 may be configured to have a curved-shape. The connecting member 2 is connected to the rear end 10 of the main tubular portion 10 of the feeding tube 1, and defines an accommodating space 21 that is in spatial communication with the passage 101 and that has a cross sectional area larger than that of the passage 101. The connecting member 2 and the feeding tube 1 are integrally 15 formed as one piece in the embodiment. Referring to FIG. 4, the oral-feeding device is used with a delivering device 3. In this embodiment, the delivering device 3 is configured as, for example and not limited to, a syringe removably connected to the 20 oral-feeding device. The delivering device 3 includes a hollow syringe barrel 31 that defines a containing space 311 in fluid communication with the passage 101 of the feeding tube 1, and a plunger 32 that is slidably disposed in the containing space 311. 25 Referring to FIGS. 3 to 5, in use, the containing space 311 of the syringe barrel 31 of the delivering device 3 is first filled with the flowable material 5, and then the 1001214992 6 front end of the delivering device 3 is inserted into the accommodating space 21 of the connecting member 2. Prior to feeding of the turtle 6 (see FIG. 5) by the oral-feeding device, the plunger 32 of the delivering device 3 is pushed 5 until the flowable material 5 is advanced into and completely filled in the passage 101 of the feeding tube 1 so as to prevent air in the passage 101 from being injected into the oesophagus (not shown) of the turtle 6. Next, the flat portion 11 of the feeding tube 1 is brought to abut 10 against the mouth of the turtle 6, and then inserted into the mouth of the turtle 6, passed past the trachea of the turtle 6 and inserted into the oesophagus. At this time, the plunger 32 of the delivering device 3 can be pushed again so that the flowable material 5 from the containing space 15 311 of the syringe barrel 31 flows out from the outlet 103 via the passage 101 and onto the receiving surface 111 of the flat portion 11, and eventually enters the oesophagus of the turtle 6. Since the flat portion 11 of the feeding tube 1 is flat 20 and thin, it can be easily inserted into the mouth of the turtle 6 even when the mouth of the turtle 6 is closed tightly or the turtle 6 refuses to be fed. The arc-shaped front edge of the flat portion 11 provides a relatively low possibility of injuring the mouth of the turtle 6. The inclined end 25 surface 104 of the main tubular portion 10 of the feeding tube 1 allows the main tubular portion 10 to be gradually and easily guided into the mouth of the turtle 6. The designs 1001214992 7 of the flat portion 11 of the feeding tube 1 and the inclined end surface 104 effectively reduce the time and effort spent on feeding the turtle 6, and enable successful delivery of a desired amount of the flowable material 5 into the mouth 5 of the turtle 6 without the need of using an aiding tool. Moreover, since the outlet 103 is formed in the inclined end surface 104 of the main tubular portion 10, the area of the outlet 103 is larger than that of the inlet 102. Such configuration enables a user to easily spot the flowable 10 material 5 flowing out of the outlet 103. In addition, the receiving surface 111 of the flat portion 11 of the feeding tube 1 receives the flowable material 5 flowing out of the outlet 103 and thus prevents the flowable material 5 from dropping onto the ground or into the environment when the 15 plunger 32 of the delivering device 3 is pushed for venting out the air in the passage 101 of the main tubular portion 10 of the feeding tube 1. In this embodiment, the turtle 6 is used as an example of the feeding object. In actual use, the animal may be, 20 for example and not limited to, pets such as birds, snakes, lizards, monkeys, minks, or laboratory animals such as rats, rabbits, etc. It should be noted that the oral-feeding device is not limited to be used for feeding purpose, and may be used for 25 cleaning or injection purposes. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute 1001214992 8 an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. 5 1001214992