Effect of extrusion on the quality of soybean-based catfood

Cat digestibility studies were carried out using 10 adult, castrated cats. The composition of the tested diet was as follows: 20 % fullfat soybean mea l, 40 % meat meal, 39 % corn, 0.5 % salt and 0.5 % mineral-vitamin premix. The trial was carried out in three phases. First the digestibility of the d ry extruded pellet was measured. The digestibility of the raw mixture was m easured by indirect trial, using a rabbit meat-based basal diet: 60 g basal and 30 g unextruded diet were mixed. The digestion of the different diets varied: dry matter 71, 56 and 72 %; organic matter: 76, 58 and 76 %; crude protein: 75, 58 and 76 %; ether extract: 93, 88 and 91 %; and N-free extrac t: 72, 34 and 72 %, for the extruded, unextruded and rabbit meat, respectiv ely. Extrusion significantly improved the palatability of the fullfat soybe an-containing diet, so that sufficient dry matter intake can be assured by feeding this type of diet. The digestibility of the corn-soybean-based, ext racted mixture is as good as that of the rabbit meat-based diet. The digest ibility of nutrients of the untreated raw mixture were 5-36 % lower than th ose of the extruded food.