| Popis: |
Whole cottonseed extruded at temperatures (°C) and rates (kg/h) of 131, 314; 135, 182; 146, 195; and 156, 286 was evaluated by protein solubility, in vitro ammonia concentration, and in situ disappearance techniques. These techniques were used to estimate potential of extruded whole cottonseed for protein escape from the rumen. In addition, raw whole cottonseed, soybean meal, corn gluten meal, and whole cottonseed and soybean meal heated for 4h at 127, 138, and 149°C were used for comparison. Solubility was by three methods: cold water mixed for 30min, cold water homogenized for 5s, and hot water refluxed for 1h. In vitro ammonia concentration was measured after 2, 4, and 6h of incubation. Dry matter and CP disappearance was estimated using nylon bags suspended in the rumen for 1, 2, 4, 8, 12, and 24h. Extrusion reduced solubility of cottonseed as measured by all three methods. There was no difference in ammonia concentration due to extrusion. Whole cottonseed responded similarly to extruded products at all time intervals. Extruded products differed over time with the in situ technique. The two highest extrusion temperatures resulted in mean DM and CP disappearance rates of 1.32 and 1.32%/h compared with whole cottonseed (1.52, 6.08) and the other extrusion treatments (1.96, 2.92). |
