Hi DaudLa,
I have been feeding my Maine Coons with a combination of raw chicken livers, chicken fillet and top side beefs daily and occassionally on weekends with Salmon or Mackerel for the past 6 months and they love it to bits. Vitamin supplements on weekends too.
Each individual cat have different needs exactly. What you need to focus on is what works with your cat. If kibbles such as Orijen/Acana/Evo works for your cat than Orijen/Acana/Evo it is and if it is Whiskas; Whiskas it is. When it is even nasi with boiled fish, as long as your cat enjoys it and is healthy eating it.
My Maine Coons are big in size, healthy and no vet visit at all since I fed them with raws compare to kibbles. Not even a flu. My Queen Maine Coon just delivered 1 healthy kitten on January 23rd 2012. As I am typing this, I am looking at her feeding her baby with no problem at all.
You can read this
http://www.petfinder.my/blogs/posts/..._Caviar_HQ.htm for more infos and this following statement "Mr Teh hit the nail on the head when he said there is actually no one food that is THE best food. It is all about finding the best food for your dog and every dog has its own needs. He cites the example of a dog that was given ultra premium kibble but had diarrhoea. This particular dog only does well on one of the cheapest kibble brands! His coat would be ever shiny and his health at its peak…on that cheap kibble food!". Substitute the "Dog" statement with "Cat" and it carries the same message.
Have a great endeavor and love with your Maine Coon. Please visit a Vet for the 'Boroi" tummy, just to be sure. It is normal for cat to get sick as human does too, any living thing exactly.