Effect of protein source and enzyme supplementation on ileal protein digestibility and fattening performance in rabbits

An experiment was conducted to determine the effects of source of protein (soybean vs sunflower meal) and enzyme supplementation (no enzyme vs protease addition vs protease + xylanase addition) on digestion and growth traits of rabbits. Treatments were arranged factorially in six isonutritive diets. Two hundred and forty rabbits weaned at 25 or 35 days were used to measure dry matter and crude protein apparent ileal digestibility of diets at 35 or 45 days of age, respectively. Another one hundred and eighty animals weaned at 35 days were fed ad libitum in individual cages during four weeks to determine fattening performance. Source of protein did not affect digestion efficiency or feed conversion rate in the whole fattening period, but animals fed soybean meal-based diets showed higher feed intake, grew faster and had higher mortality than those fed sunflower meal-based diets. Addition of enzymes increased ileal apparent digestibility, especially in youngest animals when supplements contained xylanase besides protease activity. Enzyme supplementation did not affect any of the growth traits studied, but decreased fattening mortality in sunflower meal-based diets.