METHODOLOGICAL ASPECTS OF THE MOBILE NYLON BAG TECHNIQUE IN PIGS

Six pigs fitted with duodenal cannulas were used to determine the influence of washing the bags on the apparent digestibility of the dry matter and the protein in two diets (high or low digestibility) determined with the mobile nylon bag technique. The results were compared with those obtained by conventional methods. When the bags were washed, the digestibilities observed were higher than the in vivo values but the variability was low, while the unwashed bags gave lower results with a high variability between the bags. A second experiment was performed with two pigs to determine the influence of the predigestion of the samples to simulate the gastric digestion, the size of the bags, the nylon pore size, the grinding of the samples and the weight of the samples. Each factor, except the size of the bags, did influence the results of digestibility determined.