Feeding Value and Digestibility of Soybean Hulls for Swine

Abstract

The inclusion of soybean hulls (mill feed or mill run) in swine diets was evaluated in three trials using 240 crossbred pigs (initial weights3x2014; 16 to 30 kg) fed fortified corn-dehulled soybean meal diets containing from 2 to 24% hulls. All diets were isonitrogenous and were fed ad libitum. A 16% protein diet was fed to 52 kg and a 14% for the remainder of each trial. Soybean hulls analyzed (% on dry matter basis): crude protein, 13.6; crude fiber, 47.0; ether extract, 2.5; ash, 5.1; NFE, 31.8; cell walls, 67.2; cell content, 32.8; hemicellulose, 17.7; ADF, 49.5; cellulose, 45.8; lignin (KMnO₄ method), 3.2. Gross energy of hulls was 4,320 kcal/kg. Daily feed intake increased linearly as the proportion of hulls in the diet increased. Average daily gain was depressed when the diet contained 4% hulls and appeared to be highest when the diet contained 6% hulls. Feed per gain was similar for diets containing up to 6% hulls, but was increased in a linear manner for diets containing 12 and 24% hulls. Twelve crossbred barrows initially weighing 46.3 kg were used in a 3 ✕ 3 Latin square digestion trial to determine the digestibility of various nutritive components of soybean hulls. Hulls were substituted at levels of 15 and 30% for a 13% crude protein diet containing 63% corn, 20% oats, 5% dehydrated alfalfa meal, 10% soybean meal plus minerals and vitamins. Barrows were fed 11% of metabolic body size each day in two equal feedings. As soybean hulls were substituted for the basal diet, digestion coefficients for dry matter, energy, crude protein, ether extract, NFE, cell content and ash were decreased, while digestion coefficients for ADF, cellulose and lignin were increased. There was a trend for crude fiber digestion to increase as hulls were substituted while the digestion of cell walls and hemicellulose was unaffected. The predicted digestibilities for soybean hulls calculated by difference using the percentage of that nutrient which was from hulls were (%): dry matter, 49.7; energy, 47.5; crude protein, 32.0; ether extract, 20.4; ash, 31.1; NFE, 73.0; cell content, 47.5; crude fiber, 44.2; cell walls, 54.2; ADF, 48.8; cellulose, 47.6; hemicellulose, 60.8; lignin, 65.9. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.