Effect of expander conditioning and/or pelleting of a diet containing tapioca, pea and soybean meal on the total tract digestibility in growing pigs

A study was carried out with piglets fed a complete diet containing mainly peas, soybean meal and tapioca. The diet had been processed in four different ways: by pelleting without steam addition (CP), steam pelleting (SP), expander treatment (E) and expander-pelleting (EP). er-pelleting clearly increased pellet durability and pellet hardness as compared with CP and SP treatment. The effect on the diet starch gelatinization degree (SGD) was small due to the high SGD of the unprocessed meal. l tract digestibility experiment with piglets revealed no differences in the apparent digestibility coefficients for dietary protein, dry matter and nitrogen-free extract. The digestibility coefficient for fat was significantly (P < 0.01) lower for the expandate compared with the SP diet. Both expander treatments decreased the digestibility 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. the conditions of the present study, the use of high-shear conditioning (expander treatment) prior to pelleting had no favourable effect on the apparent digestibility of nutrients in diets for growing pigs.