Abstract:
Animal Production in Australia Vol. 15 EVALUATION OF EXTRUDED SOYBEANS AS A RATION INGREDIENT FOR PIGS WEANED AT 24 DAYS OF AGE R.R. CARTER*, D.F. EVANS** and D. LOVATT*** Wilson et al (1981) showed that the substitution of milk protein by soybean meal reduced growth in pigs from seven to 28 days of age. Whilst pigs younger than 18 days of age were not able to utilize soybean flour efficiently, from 21 to 36 days of age soybean flour was equivalent to milk protein (Jones et al 1977). This experiment was designed to evaluate whole soybeans processed by the 'Insta-Pro' dry extrusion method as a dietary ingredient for pigs weaned at 24 days of age. Four wheat-based diets were compared with the following levels of test ingredients: 380g/kg extruded soy containing three trypsin inhibitor units/ mg (AOCS, 1982) (1); 380g/kg extruded soy containing 17 trypsin inhibitor units/ mg (2); 48Og/kg dried skim-milk powder (3); 360g/kg extruded soy (three TIU/mg) plus 32Og/kg dried whey powder (4). These diets were fed ad lib for 28 days and were blocked such that each treatment had four replicates with seven mixed sex pigs per replicate. Chromic oxide was used as a marker. TABLE 1 Effects of diet on ADG, apparant DM and N digestibility for the periods 24-38 days, 38-52 days and 24-52 days of age *Superscripts denote significant differences (a-c) (P(O.05) Low trypsin inhibitor extruded soy plus whey resulted higher ADG than other diets for the first 14 days. Improved and FCR for the first 14 days resulted from the inclusion of lower trypsin inhibitor level in diet one resulted in higher ibility coefficients for the first 14 days compared with the two. in a significantly ADG for the 28 days milk products. The DM and N digesthigher level in diet Pig growth will benefit from feeding 'Insta-Pro' extruded soy provided processing ensures low trypsin inhibitor levels. Further improvements in growth and FCR are incurred by the combination with whey powder. AMERICAN OIL CHEMISTS' SOCIETY (1982) 'The Official and Tentative Methods of the American Oil Chemists' Society' Ed. R-0. Walker (American Oil Chemists' Society). JONES, E.E., COALSON, J.A. and LECCE, J.G. (1977). J.Anim.Sci. WILSON, R-H. and LEIBHOLZ, Jane (1981). Br.J.Nutr. 45:301, 45:1073. *Bayer Aust. Ltd., Veterinary Division, 47-67 Wilson St., Botany,N.S.W. **Wonga Projects Ltd., P-0. Box 50, Young, N.S.W. ***Petersville Aust. Ltd., 254 Wellington Rd., Mulgrave, Vic. 662
