Broken beans (Phaseolus vulgaris) use on extruded diets for cats
Broken beans (BB) is the result of bean selection for human consumption, mainly composed of open seeds in good sanitary and nutritional quality, with a potential use as protein and energy source for companion animals. Beans have antinutritional factors, among then protease inhibitors (PI) and hemagglutinin (HA) that reduces the ingredient nutritional value. These factors are thermolabile, and the extrusion process used to produce kibble diets for cats may possibly inactivate them. We evaluated the inclusion of BB on extruded diets for cats, and the effect of the extrusion process on PI and HA inactivation. Thirty adult cats, with 7.6±0.3 years old and 5.0±0.3 kg of BW were used. Five diets with similar composition (average: 94% DM, 30% CP, 16% fat, 2.8% crude fiber, 7% ash) were formulated for cat maintenance, presenting increasing amounts of BB: 0.0%, 7.5%, 15.0%, 22.5% and 30.0%. The BB sample presented 22.1% of CP, 1.5% of fat, 3.7% of crude fiber, and 2.9% of ash, and was included at the expense of the poultry by-product meal. Diets were extruded under similar conditions in a laboratory scaled complete extrusion system, with a single screw extruder. Samples from the mash diet and the food after the preconditioner, extruder, and dryer were collected and used to measure TI and HA. The experiment followed a complete randomized block design, with 2 blocks of 15 cats, and 3 cats per diet in each block, totaling 6 cats per diet. The blocking factor was time. The coefficients of apparent total tract digestibility and nitrogen balance was determined through total collection of feces and urine. Cats were kept in metabolism cages during 14d, and feces and urine were totally collected on the last 7d. Data were submitted to analysis of variance, and means compared by polynomial contrasts (P<0.05). The extrusion process was very efficient in inactivate the PI and HA of the BB. After the preconditioner, the activity of these compounds was reduced in 40% to 50%, after the extrusion, they were reduced more than 90%, and after the dryer their values were practically zero. Addition up to 30% BB did not change food intake, nutrient and energy digestibilities (average digestibility: DM, 81%; OM, 84%; CP, 85%; acid-hydrolyzed fat, 89%; gross energy, 86%), fecal traits (dry matter, production, and score), and nitrogen balance, suggesting that bean is a suitable ingredient for extruded diets for cats.
Keywords: co-products, protein, antinutritional factors