The effect of a high ambient temperature on the apparent ileal digestibility of amino acids and nitrogen in growing pigs

A total of 7 gilts (initial BW 50.5 ± 1.7 kg) fitted with a simple T-cannula in terminal part of ileum were used for the determination the effect of high ambient temperature on the apparent ileal digestibility (AID) of amino acids (AA) and nitrogen (N) and on the apparent total tract digestibility (ATTD) of N and dry matter (DM). After the 5 d adaptation period two 14 d experimental periods followed. After the 1st 14 d period when the animals were housed at thermo-neutral (TN) temperature (20.6 ± 0.1 ºC), the 2nd 14 d period followed at high temperature (HT) (30.4 ± 0.4 ºC). On d 7 and 14 of each experimental period, two 24 h collections of ileal digesta and 2 collections of faeces were performed. The pigs were fed twice a day in two equal doses at a daily rate of 90 g*kg BW -0.75. The content of AA in samples of diets and ileal digesta was determined by an automatic amino acid analyzer (AAA 400, Ingos, Prague) after previous acid hydrolysis in 6M HCl with the exception of methionine and cysteine which were determined after oxidative hydrolysis. Water was offered ad libitum. The ATTD of N and DM at TN was 84.9 and 85.3%, respectively and the ATTD at HT was 84.7% and 86.5% for N and DM, respectively. Apparent ileal digestibility of AA and N were similar at both TN and HT ambient conditions. High ambient temperature had no adverse effect on ATTD of N and DM nor on the AID of N and AA in pigs