Apparent digestibility coefficient of soybean meal,rapeseed meal,meat and bone meal and feather meal for Nile tilapia(Oreochromis niloticus)

Apparent digestibility coefficient(ADC)of dry matter,protein and energy of soybean meal,rapeseed meal,meat and bone meal and feather meal for Nile tilapia,Oreochromis niloticus(body weight 101 g)were measured in an indoor experiment.The test diets were formulated to contain 70% the reference diet and 30% the tested ingredient.Chromic oxide(Cr2O3)was added at 1% in the reference diet as an inert marker.The fish were fed the reference diet for three days,and then fed the test diets in following four days every week.Fecal samples were collected from the second day after feeding of each diet during the experiment.Results of the present study revealed that the ADC of dry matter of soybean meal,rapeseed meal,meat and bone meal and feather meal for Nile tilapia was 68%,47%,58% and 58%,the ADC of protein of these feed ingredients was 100%,83%,78% and 77%,the ADC of energy of these feed ingredients was 76%,61%,78% and 70%,respectively.In comparison,soybean meal is an excellent dietary protein source for Nile tilapia.The use of rapeseed meal as dietary protein source in Nile tilapia diets can result in low digestible energy,and the use of rapeseed meal and meat and bone meal in combination could be a solution to this problem.