UTILIZATION OF PROTEIN FROM PEAS, BARLEY, BUTTERMILK POWDER AND SOYBEAN MEAL BY EARLY-WEANED PIGS

Abstract

Six pairs of newly weaned 21-day-old pigs were assigned to each of four diets where 80% of the dietary protein originated from soybean meal (SBM), buttermilk powder, barley protein concentrate or pea protein concentrate (PPC). The remainder of the protein came from naked oats. From 21 to 42 days of age, daily gains on the SBM (327 g) and buttermilk powder diets (355 g) did not differ, but were lower (P < 0.05) on the barley protein concentrate (259 g) and PPC (171 g) diets. Daily feed intake was less (P < 0.05) for the PPC diet (262 g) than for the SBM, buttermilk powder or barley protein concentrate diets (448, 445 and 368 g, respectively). Apparent digestibility of dietary crude protein increased by 5–10 percentage points from 28 to 41 days of age. On the basis of the known protein digestibility of the naked oats, and using the mean protein digestibility value of each diet, the protein digestibility of each protein source was calculated to be: SBM, 76%; buttermilk powder 86%; barley protein concentrate, 86%; and PPC, 69%. In a second experiment, diets were formulated so that PPC supplied 0, 27, 53 or 80% of the dietary protein. There was a general decline in growth rate and in feed intake as pea protein increased, with a marked decrease in growth rate at the final PPC increment. It is suggested that PPC should not contribute more than 27% of the dietary protein (10% of the diet) for weanling pigs. Key words: Weanling pigs, pea protein, buttermilk powder, barley protein, soybean meal, digestibility