Nice close shot, but I fear that by NOT showing the Lions surroundings there is doubt as to the authenticity of where he was photographed. As long as you do truthfully mention it then no problem. He is also too pristine to be a wild lion. One noticeable scratch on the nose ridge and a near perfect mane is sign of a pampered lion. A few wildlife togs, myself included, often try to get the natural AFRICAN bush in the shot so that there is no doubt. This can however stifle creativity, especially animal abstracts. Sure NG have done stories about captive animals so this is not a reason for them not to publish. However, it's blurred due to a too slow shutter speed and thus camera/lens shake and would not pass their strict selection.
I like the subject matter but the focus needs to be better on the eyes, the colour just isn't reaching me and I'd like to see the top of the mane too please.