A tigon is a hybrid cross between a male tiger (Panthera tigris) and a female lion (Panthera leo). Thus, it has parents with the same genus but of different species. The tigon is not currently as common as the converse hybrid, the liger.The tigon’s genome includes genetic components of both parents. Tigons can exhibit visible characteristics from both parents: they can have both spots from the mother (lions carry genes for spots—lion cubs are spotted and some adults retain faint markings) and stripes from the father. Any mane that a male tigon may have will appear shorter and less noticeable than a lion’s mane and is closer in type to the ruff of a male tiger. It is a common misconception that tigons are smaller than lions or tigers. They do not exceed the size of their parent species because they inherit growth-inhibitory genes from the lioness mother, but they do not exhibit any kind of dwarfism or miniaturization; they often weigh around 180 kilograms (400 lb).
Bella may be breathing normally if she is otherwise acting like herself, but she may be having breathing difficulties. Typically when cats are having problems breathing, they don't lie comfortably, and she may be fine. If you are not sure, with any breathing issue it is always better to be safe than sorry, and it would be wise to have her examined.