Effect of different irradiation methods on different protein fractions, ruminal degradability and intestinal digestibility of sunflower meal protein

Irradiation can be used as substitute method for oilseeds processing in ruminant nutrition. This experiment was conducted to compare the effect of roasting and gamma, electron, microwave and infrared irradiation on different protein fractions, ruminal degradability and intestinal digestibility of sunflower meal protein. Sunflower meal processed by different irradiations. Four ruminally fistulated Moghani rams with average body weight of 61±2 kg were used to measure ruminal degradability of crude protein using nylon bag technique. Intestinal digestibility and different protein fractions were measured using three-step enzymatic procedure and Cornell net carbohydrate and protein system, respectively. Roasting and different irradiation methods decreased protein A and B1 fractions of sunflower meal and increased B2 fraction (P<0.05). The highest value of B3 and C fractions were observed in microwave and infrared irradiated sunflower meal (P<0.05). The highest and the lowest values of quickly degradable fraction ("a" fraction) of protein were observed in unprocessed and infrared irradiated sunflower meal, respectively (P<0.05). Roasting and different irradiation methods decreased slowly degradable fraction ("b" fraction), degradability rate ("c") and effective degradability of sunflower meal protein (P<0.05). The lowest effective degradability of protein at 0.02, 0.05 and 0.08/h passage rate was observed in gamma irradiated sunflower meal (P<0.05). Intestinal digestibility of sunflower meal protein increased by roasting and different irradiation methods (P<0.05). Gamma and infrared irradiation had better effect on reduction of ruminal degradability and increase of intestinal digestibility of sunflower meal protein compared to electron radiation and microwave.