Protein Degradation by Rumen Microbes of Heat-Treated Whole Cottonseed

In vitro and in situ rumen digestion trials were conducted to measure the effect of heat treatment on protein degradation by rumen microbes of cottonseed autoclaved and dry-heated (120, 140, 160 and 180 C) for different lengths of time (20, 40, 60, 90 and 120 min). Autoclaving (120 C, 1 kg/cm2 of pressure for 60 min) was effective in reducing ammonia nitrogen concentration in vitro, but dry heat at this temperature was without effect. Dry heating caused a linear decrease of in vitro ammonia concentration as temperature increased from 140 to 180 C and as exposure time increased from 20 to 120 min. The in situ results corroborated the in vitro findings. Crude protein disappearance from dacron bags decreased from 87 to 48% as temperature increased from 140 to 180 C after 20 min of heating.