Metabolism and Nutrition: Nutrition

The urease activity index (UI) is a laboratory test to identify underprocessed soybeans. An experiment was conducted to compare the cor­ relation coefficient of laboratory test with some biological experiment to evaluation of extruded full fat soybean (EFFSB). One hundred fortyfour day-old male broiler chicks were divided into 12 groups including 3 treatments with 4 replicates and fed 3 diets containing 15% full fat soybean wet extruded at 145, 155, and 165°C from 0 to 42 d of age. The UI measured in EFFSB samples as a laboratory index to identify under-processed soybeans. Some biological data including weight gain (WG), pancreas relative weight (PRW), blood oxygen saturation (BOS) and jejunal villi length (JVL) measured during the experimental period then determined the correlation coefficients of these biological data with laboratory test (UI). Results showed that PRW at 21 and 42 d chicks had highest correlation with UI (80 and 89%, respectively) as compared with other biological data. Also the UI values showed higher correlation with all biological data in 42-d chicks as compared with biological data of 21-d chicks. It is concluded that the best biological test to evaluate the FFSB extrusion in broilers is measuring the pancreas relative weight of chicks at 42 d of age.