Evaluation of in vivo techniques for the determination of apparent ileal amino acid digestibilities in feedstuffs for piglets

Three in vivo techniques were evaluated in terms of their suitability for d etermination of the apparent ileal amino acid digestibility (AID) of protei n sources for piglets. The techniques were: ileo-rectal anastomosis (IRA), cannulation at the distal ileum and a slaughter technique. A standard diet and three diets in which 20% of the standard diet was substituted with eith er skim milk powder (SMP), fish meal or roasted full-fat soya beans (FFS) w ere used. Piglets were weaned at 21 days of age, and the respective diets w ere fed in 24 equal hourly portions per day from days 29-37. Ileal digesta was collected from day 33-37 in IRA and cannulated piglets. Piglets used fo r the slaughter technique were killed at 37 days of age and ileal digesta w as collected. Chromium III oxide was used as an indigestible marker with al l three techniques. Although AID means did not differ (p > 0.05) between th e different techniques, the cannulation technique resulted in the lowest va riation (standard error of the mean) of all treatments (8.2 vs 13.7 and 14. 1 for the slaughter and IRA-techniques respectively). AID means obtained us ing the cannula technique were 1.8 percentage units higher for the SMP diet than values obtained using the other techniques (83.2 versus 81.4 %), and up to 9.3 percentage units higher for the FFS diet (75.4 versus 66.1 %). Gr owth data suggested that the cannulation technique caused less trauma for t he piglets than the IRA-technique. IRA-piglets had not yet regained their i nitial weaning weight by 37 days of age, while the other piglets gained wei ght over the trial period. The cannulation technique is the most attractive method for use with piglets in terms of the lower variation in digestibili ty values. Practical aspects such as ease of handling and sampling, surgica l trauma and piglet stress, are also important and contribute to the select ion of the cannula technique as the most appropriate.