Influence of different cannulation techniques on the pre-caecal digestibility of protein, amino acids and cell wall constituents from diets, containing different protein meals, in pigs

Abstract A direct comparison of the ileal digestibility of protein, amino acids and cell wall constituents, measured using the simple cannula (spot sampling) and re-entrant cannula (quantitative sampling) techniques, was carried out with six pigs fitted with each type of cannula. During the experiment, the live weights of the animals ranged from 40 to 90 kg. Six diets were offered, including the following: a commercial ration commonly used in China which is based on maize, rice husk meal and fish meal (B); two diets in which part of Diet B was replaced by 15% oil-tea camellia cake (BTM) or rapeseed meal (BRM); two monodiets of maize with a high (MHL) or low (M) lysine content, plus Diet M with 15% of the maize replaced by peanut meal (MPM). Chromic oxide formed 2 g kg −1 of the diets to permit calculation of digestibility by spot sampling. With the exception of one maize diet and the MPM diet, the spot-sampling method gave higher digestibilily values for dry matter, protein and amino acids than the quantitative sampling method. Conversely, the digestibility values of neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) measured with the simple cannula technique were considerably lower than these measured with the re-entrant technique. This study indicated that the re-entrant cannula technique cannot be replaced by the simple cannula technique in the determination of pre-caecal digestibility in monogastrics, particularly the digestibility of cell wall constituents of compound feeds.