PSVIII-33 In vitro DM and NDF degradability of signal grass and forage peanut. (7th December 2018) - Cardoso, L
Abstract: The objective of this study was to evaluate the in vitro dry matter (DM) and neutral detergent insoluble fiber (NDF) degradability of Urochloa decumbens (UD), Arachis pintoi (AP), and 50:50 mixture (UD: AP). A half gram of sample ground to 1-mm sieve was conditioned in Ankom ® bags, in duplicate for each incubation time (0, 3, 6, 12, 24, 48, 72, and 96 h), in three incubation periods. Ruminal content was collected from sheep receiving a similar diet, with 15 days of adaptation to diets followed by three periods of seven days each. The ruminal content was collected on the last day of each period, stored in preheated thermal bottles under anaerobiosis condition, hermetically isolated, and the inoculum filtered through a double cheesecloth layer under continuous injection of CO2 and subjected to water bath at 39 ºC. The bags containing the samples were placed in reverse order in a Daisy II incubator, so that they were all removed at the same time, washed manually, and subsequently subjected to DM and NDF analyzes. The degradability was calculated through the equation: ŷ = a/[1+(C)(e -bt )], in which ŷ is degradation in time (g), a is the asymptote when time is zero, C is the constant related to degradation, b is the degradation rate (g/h), and t is the incubation time (h). The adjusted equations for DM and NDF degradability were, respectively, UD: ŷ=0.17439/[1+(0.11398) (e -0.02425T )] (R 2 =0.92) and ŷ=0.02627/[1+(0.2701)(e -0.0046T )] (R 2 =0.95); UD:AP: ŷ= 0.116198/[1+(0.09373)(e -0.02973T )] (R 2 =0.92) and ŷ=0.03364/[1+(0.2103)(e -0.0045T )] (R 2 =0.93); AP: ŷ=0.13395/[1+(0.12054)(e -0.105288T )] (R 2 =0.92) and ŷ=0.13099/[1+(0.08354)(e -0.04455T )] (R 2 =0.92). The DM degradation rate was 0.02425, 0.02973, and 0.105288 g/h and NDF degradation rate was 0.0046, 0.0045, and 0.04455 g/h, respectively, for UD, UD:AP, and AP. The DM and NDF degradation rates in A. pintoi were, respectively, 4.3 and 9.7 times higher than in U. decumbens .