Crude fiber content of medium and large pigs

What is the appropriate content of crude fiber in medium and large pigs without affecting growth? How much do you add to wheat bran?-the fiber is about 10%. The quality of wheat bran is difficult to control. It seems that some feed factories are looking for substitutes. -- preferably less than 8%. Wheat bran has a mild diarrhea effect, so it's best to control it within 15%-- usually 10%.