Effect of processing on the protection of highly degradable protein sources in steers

Abstract

The effect of heat treatment (125°C for 3 m), formaldehyde treatment (3.4g /100 g CP) or extrusion cooking on the protein disappearance and the effective protein degradability (EPD) of protein sources such as babul seed meal, coconut cake, dried poultry waste, guar meal, mustard cake, rape seed meal and tobacco seed cake in the rumen was studied by nylon bag technique using 4 fistulated steers fed at maintenance ration. Formaldehyde treatment was highly effective in reducing the EPD of babul seed meal, mustard cake, rape seed meal and tobacco seed cake. Heat treatment was effective in protecting the protein of rape seed meal, mustard cake and coconut cake. The effect of extrusion cooking in reducing EPD was low (5.96%) as compared to 31.8% in heat treatment and 39.2% in formaldehyde treatment. The dried poultry waste and guar meal were found to be resistant to different processing methods employed. Method of processing did not influence the nitrogen content of protein sources as there was no loss or gain in nitrogen content due to processing.