Digestibility of crude protein and fat from feed rations for minks with different proportions of meat - bone meal

The aim of the experiments was to find out the digestibility of crude protein and fat in feed rations for minks with different percentage proportions of meat-bone meal as well as the digestibility of the nutrients in meat-bone meal. Five male standard minks at the age of one year were used in the experiment. The experiment consisted of three periods. During the first period (K) were the animals fed the control diet, which contained the least amount of meat-bone meal - 8.1 %. The content of meat-bone meal raised to 15.6, 18.8 % out of the original matter during the following two periods (P1, P2). The animals were housed in special balance cages one month before the start of the experiment to adapt themselves to the new environment. Each period of the experiment consisted of two stages - the preparation stage and the trial. The preparation stage lasted seven days during which the animals became used to the new diet, and the trial itself lasted five days. The individual stages followed each other immediately. The animals were fed two times a day at 9.00 o'clock and 15 o'clock. During the experiment we followed the parameters necessary for the calculation of digestibility coefficients in animals, i.e. the feed intake, residua of unconsumed feed and amount of excrements. Samples were taken two times a day, always one hour before feeding. The content of nutrients was determined in samples of feed and excrements by the chemical analyses. Digestibility of crude protein and fat was determined by the balance substance digestibility (indirect method). The obtained results were processed statistically by two-way variance analysis with selected comparisons of feed digestibility. The value of the coefficient of crude protein digestibility was 62.14 % in the first period of trial with control feed ration, 57.61 % with 15.6 % proportion of meat-bone meal in the second period, and 56.79 % with 18.8 % proportion of meat-bone meal in the third period. The value of digestibility coefficient in fat was 94.65 %, 93.47, and 93.24 % in the studied periods. The average digestibility of crude protein in meat-bone meal was 33.44 % and of fat 87.12 %. On the basis of the results we recommend for the agricultural practice 8 % proportion of meat-bone meal as the maximum in the feed rations for minks