DIGESTIBILITY AND AVAILABILITY OF PROTEIN AND PHOSPHORUS IN PIGS FED WET BARLEY PROTEIN AND WET DISTILLERS SOLIDS FROM INTEGRATED STARCH-ETHANOL PRODUCTION

The nutritive value of two high protein feeds from the integrated star ch-ethanol production from barley, wet barley protein (WBP) and wet di stillers solids (WDS) were studied in two experiments with pigs. In ex periment 1 the apparent ileal and total tract digestibility of protein and ileal digestibility of amino acids were determined using six grow ing pigs fitted with a T-shaped cannula at the end of the ileum. In ex periment 2 the apparent total tract digestibility and availability of protein and phosphorus were determined using nine finishing pigs. Expe riments were carried out on different batches of feeds. Feeds were inc luded in semi-purified diets as the only source of protein (experiment s 1 and 2) and as the only source of phosphorus (experiment 2). WBP co ntained less protein and phosphorus than WDS (332 and 7.0 g kg(-1) dry matter (DM) vs. 518 and 11.3 g kg(-1) DM, respectively). The crude pr otein in WBP also contained less lysine (3.0 g 16 g(-1) N) than the cr ude protein in WDS (3.9 g 16 g(-1) N). The apparent ileal digestibilit y of protein and most of the amino acids were significantly higher for WBP than for WDS. The respective values were: for protein 83.6% and 7 9.9% (P < 0.01), for lysine 84.7% and 80.5% (P < 0.01), for methionine 91.6% and 85.5% (P < 0.001), for cystine 85.1% and 79.6% (P < 0.001) and for threonine 80.1% and 74.3% (P < 0.01). Similarly the feeds also differed in the apparent total tract digestibility of protein. Pigs r etained more nitrogen after feeding on lysine-supplemented diets conta ining WDS than on those containing WBP. Phosphorus availability tended to be higher for WDS diets than for WBP diets (42.3% vs. 33.2%, P < 0 .10) and accordingly differed in its retention in pigs (P < 0.05).