Degradability characteristics of dry matter and crude protein of Growia tenax using the in situ and in vitro techniques in ruminants

الملخص EN

Leaves, Green shoots, fruits and Seed cake of Growia tenax were evaluated in terms of the following, dry matter (DM) and crude protein (CP) digestion characteristics: soluble fraction A, degradable fraction B, degradation rate, , and effective degradability .

For situ technique duplicate nylon bags were incubated for 0, 2, 4, 6, 12, , 24, 36, 48, 72 and 96 h in three bulls fitted with rumen cannulae.

The model of Ørskov and McDonald as y = a + b (1-e-ct) was used for determination of degradation characteristics.

Significant (P < 0.05) differences in degradation characteristics occurred within Leaves, Green shoots, fruits flesh and Seed cake of Growia tenax with regard to the soluble and potentially degradable DM and CP fractions.

Fruits flesh had higher soluble DM (a) (16.90 %) and soluble CP (a) (20.75 %),, Leaves had higher insoluble potentially degradable DM (b) (74.95 %) insoluble potentially degradable CP (b) (66.65 %).

Leaves had higher dry matter and crude protein degradability (62.48 %) and (72.05) respectively, followed by fruits flesh after 48 hours incubation.

It was concluded that differences in ruminal degradability exist between Leaves, Green shoots, fruits and Seed cake of Growia tenax with more variations observed for ruminal DM than for CP degradability.

Leaves can be considered an excellent source of protein for grazing and nongrazing ruminants, and can be used an emergency feed or as part of a complete diet providing that the diet contains an adequate amount of degradable protein.