Comparison of standardized ileal amino acid digestibilities in protein supplements and cereal grains for weaned pigs.

Standardized ileal digestibility (SID) of AA in protein ingredients and grains was determined in weaned piglets (5 kg initial BW) using the difference method. Animals were fitted with a simple ileal T-cannula on day 24 or 25 of age. A synthetic diet based on corn (Zea mays) starch and casein was either supplemented with an extruded soybean (Glycine max) meal (ESM), rice (Oryza sativa) protein concentrate (RPC), full fat heat-treated soybeans (SB), corn, barley (Hordeum vulgare), or wheat (Triticum aestivum). The contribution of CP and AA from casein and from the assay feed ingredients to the assay diet averaged 50% each. Each diet was fed to 6 animals according to a row-column design with 3 periods. Apparent ileal digestibility was corrected for basal ileal endogenous losses of AA to obtain SID values. Between RPC and soy products, differences (P < 0.05) in SID of most AA such as Lys, Met, and Thr were greater than within soybean products (ESM and SB). The SID of indispensable AA did not differ (P > 0.05) between barley and wheat, except for Met (P < 0.05). Furthermore, SID of Arg, His, Ile, Phe, and Trp was lower (P < 0.05) in corn than wheat. In conclusion, SID of most AA in the present study with piglets was lower than tabulated SID values determined in studies with grower-finisher pigs. Furthermore, the use of RPC, despite its high CP content, in diets for weaned piglets is limited due to its low SID of AA.

Short-term effect of dietary yeast nucleotide supplementation on total and diurnal variation of small intestinal enzyme activities in piglets.

A study was carried out to investigate, whether short-term supplementation of dietary yeast nucleotides affects total and diurnal variation of enzyme activities in the small intestine of weaned piglets. Twelve barrows, weaned at 18 d of age (5 kg initial BW), were fitted with a simple T-cannula at the distal ileum. Twice daily (0730 and 1930 h), 6 piglets each received a cereal-soybean (Glycine max) meal-based diet with or without supplementation of 1 g/kg of a yeast nucleotide product in 2 consecutive periods. In each period, digesta samples were collected 6 times at given intervals during 24 h digesta collection. Dietary supplementation with yeast nucleotides did not affect (P > 0.05) total enzyme activities for α-amylase, leucine aminopeptidase (LAP), maltase, and lactase in ileal digesta. Therefore, data of both treatments were pooled to determine diurnal variations in enzyme activities. For α-amylase, a diurnal variation in enzyme activity could be observed (P < 0.05). Variations in diurnal activities of LAP, maltase, and lactase were not observed (P > 0.05). In conclusion, yeast nucleotides do not affect total small intestinal enzyme activities. Independent of diet composition, α-amylase activities may vary over time, with peak flow at 6 h postprandially.