The objective of this study was to evaluate the effects of ultrasound processing (sonication) and 2 exogenous pure cellulase enzyme supplements on the rumen degradability of palm date seeds (PDS) under in vitro condition. The 2 enzymes were derived from Trichoderma Ressei (TR) or from Aspergillus niger (AN). The sonicated palm date seeds(SPS) were obtained by placing the PDS into 400 mL metal reactor containing 4% NaOH and then sonicating the seeds for 5 min using an ultrasonic processor (900 W, 20 kHz, 100% power level). The SPS were then recovered and freeze-dried. The PDS and SPS were then placed in Dacron bags (2.5g/bag) and incubated in 250 mL jars containing 120 mL of buffer, 30 mL of rumen fluid and 2 g of a TMR diet (50:50 forage and concentrate). Enzyme supplements were added at the rate of 60 mg/kg of diet DM. Jars were incubated in a water bath at 39°C under anaerobic and treatments were run in quadruplicate. Data were analyzed using 2-way ANOVA model of JMP. After 24 h of incubation, the average NDF_om and OM degradability of PDS were 26.4 and 23.4%, respectively, and were not affected (P > 0.05) by enzyme supplements. On the other hand, the average NDF_om and OM degradability of SPS increased to 72.2 and 67.6%, respectively, and the addition of TR, but not the AN, enzyme supplement slightly but significant (P < 0.05) increased the SPS NDF_om and OM degradability to 77.0 and 71.9%, respectively. In conclusion, sonicating PDS in NaOH solution increased their rumen degradability. The cellulase enzyme supplements had no effect on the rumen degradability of PDS but TR addition improved the rumen degradability for SPS. Table 1 (Abstr. W155). The effect of sonication and cellulase enzyme supplement on the in vitro ruminal degradability of palm date seeds¹

	PDS				SPS			MSE	P-value
PDS	PDS+AN	PDS+TR	SPS	SPS+AN	SPS+TR	Seeds	Enzymes	Seeds × enzymes
NDFom,%	26.44c	25.75c	25.88c		72.38b	72.09b	77.00a	0.763	0.01	0.01	0.01
OM,%	23.41d	22.85d	23.24d		67.56b	65.80c	71.94a	0.507	0.01	0.01	0.01

^a–cMeans with different letters within the same row are significantly different (P < 0.05). ¹PDS = palm date seeds; SPS = sonicated palm date seeds; AN = Aspergillus niger; TR = Trichoderma reesei.