Evaluation of protein degradation parameters of processed oilseed meals using NorFor system

The aim of this study was to evaluate the effects of gamma and electron irradiation on protein degradation parameters of cottonseed, sunflower, soybean and canola meals using NorFor system. The meals were processed by gamma and electron irradiation each at doses of 25, 50 and 75 kGy. Soluble crude protein (sCP) measured in vitro and both potentially degradable crude protein (pdCP) and fractional degradation rate of pdCP (kdCP) were mature determined in situ for 0, 2, 4, 8, 16, 24 and 48 hours of rumen incubation by three ruminally fistulated bulls. Gamma ray (GR) at dose of 75 kGy had the most effect on reducing sCP content of cottonseed, sunflower, soybean and canola meals (63.52, 133.22, 58.74 and 119.20 g kg-1 CP, respectively).The highest level of pdCP in cottonseed (656.41 and 759.50 g kg-1 CP respectively), canola (790.91 and 768.39 g kg-1 CP, respectively) and soybean (847.49 and 858.89 g kg-1 CP, respectively) meals was belong to the dose of kGy of GR and electron beam (EB), While in sunflower meal just the dose of 25 kGy of GR resulted in a significant increase (P<0.001) in pdCP compared to control (706.21 vs 540.25 g kg-1 CP). Results showed a high similarity between NorFor and Cornell Net Carbohydrate and Protein System (CNCPS). Utilization of NorFor system is recommended to animal nutritionists, because of facility of NorFor system in comparison to CNCPS.