Authors : H. Paya , A. Taghizadeh , H. Janamohamadi and G.A. Moghadam
Abstract: The in situ ruminal dry matter (DM) and crude protein (CP) degradation and in vitro DM and CP disappearance of corn grain, soybean meal, wheat bran and alfalfa were compared. For in situ technique duplicate dacron bags were incubated for 0, 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96 h in two wethers fitted with ruminal cannulas. The in vitro degradability of DM and CP calculated at 0, 2, 12, 36 and 48 h incubation time for test feeds. The model of Ørskov and McDonald as y = a + b (1-e-ct) was used for determination of degradation characteristics for both of methods. Wheat bran had higher soluble DM (a) (30.3%), corn grain had higher insoluble potentially degradable DM (b) (59.9%) and soybean meal had higher degradation rate (9.67% h 1) than other feeds, inverses corn grain (14%), alfalfa (40.1%) and alfalfa (3.40% h 1) had lower soluble DM, insoluble potentially degradable DM and degradation rate than other feeds, respectively. Wheat bran had higher soluble CP (a) (33.3%), corn grain had higher insoluble potentially degradable CP (b) (54.5%) and soybean meal had higher degradation rate (9.78% h 1) than other feeds, inverses soybean meal (5.7%), alfalfa (43.9%) and alfalfa (3.75% h 1) had lower soluble CP, insoluble potentially degradable CP and degradation rate than other feeds, respectively. There were differences (p<0.05) among test feeds in dry matter and crude protein degradability after several incubation times. There was strong coefficient of correlation between extent of in situ dry matter and crude protein degradation and in vitro dry matter and crude protein disappearance. The key protein parameters in the proposed Metabolizable protein system, quick digestible protein, slowly digestible protein and digestible undegradable protein are derived from measurements of the rates of degradation of feed proteins suspended in a dacron bag in the rumen. The Metabolizable protein of soybean meal (381 g kg 1) was numerically rather than the other feeds and for corn grain (86 g kg 1) was numerically less than the other feeds.
H. Paya , A. Taghizadeh , H. Janamohamadi and G.A. Moghadam , 2008. Ruminal Dry Matter and Crude Protein Degradability of Some Tropical (Iranian) Feeds Used in Ruminant Diets Estimated Using the in situ and in vitro Techniques. Research Journal of Biological Sciences, 3: 720-725.