EFFECT OF EXPANDER CONDITIONING AND OR PELLETING OF A DIET CONTAININGTAPIOCA, PEA AND SOYBEAN-MEAL ON THE TOTAL TRACT DIGESTIBILITY IN GROWING PIGS/

A study was carried out with piglets fed a complete diet containing ma inly peas, soybean meal and tapioca. The diet had been processed in fo ur different ways: by pelleting without steam addition (CP), steam pel leting (SP), expander treatment (E) and expander-pelleting (EP). Expan der-pelleting clearly increased pellet durability and pellet hardness as compared with CP and SP treatment. The effect on the diet starch ge latinization degree (SGD) was small due to the high SGD of the unproce ssed meal. A total tract digestibility experiment with piglets reveale d no differences in the apparent digestibility coefficients for dietar y protein, dry matter and nitrogen-free extract. The digestibility coe fficient for fat was significantly (P < 0.01) lower for the expandate compared with the SP diet. Both expander treatments decreased the dige stibility of crude fibre (P < 0.10). N-balance (g body N retained day( -1)) in pigs was similar for all diets but a trend was observed for a higher N-balance of pigs fed the CP diet. Under the conditions of the present study, the use of high-shear conditioning (expander treatment) prior to pelleting had no favourable effect on the apparent digestibi lity of nutrients in diets for growing pigs. (C) 1997 Elsevier Science B.V.