Ileal amino acid digestibility in high protein sunflower meal and pea protein isolate fed to growing pigs with or without multi-carbohydrase supplementation

Amino acids are the second most expensive nutrients in practical pig and poultry diets after energy. High protein sunflower meal (HiPSF) and pea protein isolate (PPI) are potential alternative protein sources for soybean meal and there is a great interest to explore their utilization as dietary ingredients for swine. Thus, eight ileal-cannulated barrows (initial BW = 23.5 ± 0.9 kg) were used to determine the apparent (AID) and standardized (SID) ileal amino acid (AA) digestibilities in HiPSF and PPI with or without multi-carbohydrase enzyme (MC) supplementation. Pigs were randomly assigned to 1 of 5 treatments in a replicated 4 × 5 incomplete Latin square design to give 8 observations per treatment. The experimental diets consisted of HiPSF or PPI as the sole source of protein with or without MC and a low-protein diet (5% casein) used to quantify endogenous AA losses. All diets contained titanium dioxide (0.3%) as an indigestible marker. Pigs were given their daily feed allowance at a rate of 4.5% of BW determined at the beginning of each experimental period. Each experimental period lasted for 7 d and the ileal digesta were collected on d 6 and 7. In general, AA digestibilities were higher in PPI than in HiPSF, with the exception of Met and Cys. There was no effect of MC on AA digestibility except for Lys, Ala, Cys and Pro in PPI. The AID and SID of essential AA in HiPSF and PPI (without MC) were, respectively: Arg, 0.86, 0.90 and 0.92, 0.95; His, 0.45, 0.54 and 0.58, 0.67; Ile, 0.78, 0.83 and 0.86, 0.90; Leu, 0.77, 0.81 and 0.86, 0.90; Lys, 0.71, 0.77 and 0.89, 0.92; Met, 0.85, 0.88 and 0.84, 0.87; Phe, 0.79, 0.82 and 0.86, 0.88; Thr, 0.68, 0.77 and 0.77, 0.85; Val, 0.75, 0.80 and 0.82, 0.87. The MC increased (P < 0.05) the AID of Lys (0.89 vs 0.91), Cys (0.59 vs 0.62) and Pro (0.79 vs 0.85) and SID of Lys (0.92 vs 0.94), Ala (0.88 vs 0.91) and Pro (0.89 vs 0.95) in PPI. Compared to HiPSF, PPI had better digestible AA profile for growing pigs. However, no differences were detected for the digestibility of most AA when diets were supplemented with MC.