GROWTH-PERFORMANCE AND GUT FUNCTION OF PIGLETS WEANED AT 4 WEEKS OF AGE AND FED PROTEASE-TREATED SOYBEAN-MEAL

Two experiments were carried out to investigate the effects of the pro tease-treatment of soya-bean meal (SBM) on its composition and nutriti ve value when fed to piglets weaned at 4 weeks of age in cereal-based diets. In experiment 1; two proteases, active at either alkaline (prot ease P1) or acid pH (protease P2), were compared with alkali or acid t reatment alone, In experiment 2, treatment with protease P2 at acid pH was compared with untreated-SBM, acid-treated SBM, a soya protein con centrate or skim milk powder + fishmeal. Protease treatment increased SBM alpha amino nitrogen concentrations and reduced in vitro SBM antig enicity, Protease P1 reduced in vitro antigenicity to a greater extent than protease P2. However, protease P1 hydrolysed SBM polypeptides no n-specifically whereas protease P2 preferentially hydrolysed a high mo lecular weight polypeptide, In experiment 1, piglets (12 diet(-1)) fed alkali-treated SBM gained more weight than piglets fed acid-treated S BM in the first 7 days after weaning, Protease Pi did not improve live -weight gain compared with alkali-treatment whereas protease P2 did im prove live-weight gain compared with acid treatment. In experiment 2, piglets (24 diet(-1)) fed protease P2-treated SBM or skim milk powder + fishmeal gained significantly more weight over the first 7 days post -weaning than piglets fed untreated SBM. In neither experiment were th ere significant differences between diets in piglet serum anti-SBM spe cific antibodies, There were no consistent changes in small intestine enzyme specific activities in response to the diets fed. Histopatholog ical examination of the small intestine of piglets in experiment 2 rev ealed no evidence of enteric disease. Neither were there any differenc es between diets in villus height or crypt depth. (C) 1998 Elsevier Sc ience B.V.