Abstract #M331

Section: Ruminant Nutrition
Session: Ruminant Nutrition: Beef I
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Gatlin Ballroom

# M331
Effects of essential oils and exogenous enzymes on in vitro rumen fermentation kinetics.
Camila Delveaux Araujo Batalha¹, Lucas Jado Chagas¹, João Ricardo Rebouças Dórea^*2, Tiago Sabella Acedo², Luis Fernando Tamassia², Cristina Simões Cortinhas², Flávio Augusto Portela Santos¹, ¹University of São Paulo, Piracicaba, SP, Brazil, ²DSM Produtos Nutricionais Brasil SA, São Paulo, SP, Brazil.

The objective with this trial was to evaluate the combination of essential oils and exogenous enzymes on ruminal DM degradation kinetics in feedlot diets. The treatments were MON (Monensin, Tortuga – 26 mg/kg DM), CRINA (Essential Oils: Crina Ruminants, DSM – 90 mg/kg DM), CRINA+MON (90 and 26 mg/kg DM, respectively), CRINA+RUM (CRINA + α-amylase: Ronozyme RumiStar, DSM – 90 and 560 mg/kg DM, respectively) and CRINA+RUM+P (CRINA+RUM+Protease: Ronozyme Proact, DSM – 90; 560 and 840 mg/kg DM, respectively). The incubated diets were composed by corn (82.5%), sugarcane bagasse (8.5%), soybean meal (5%), mineral (3%) and urea (1%). The experimental design was completely randomized, with 5 treatments and 3 replicates per incubation time. The estimated parameters of rumen degradation kinetics were soluble fraction (A), potentially degradable fraction (B), degradation rate (kd), lag time (Lag), potential degradability after 120 h of incubation time (PD = A+B). The substrate (1 g) was incubated with rumen inoculum (10 mL) and bath culture (90 mL). For each incubation time (0, 2, 4, 8, 16, 24, 48, 72, 96 and 120 h) the flask contents were filtered, dried and weighted to determine de DM disappearance. The rumen degradation parameters were analyzed using SAS system. The A and B fractions and kd were not affected by treatments (P > 0.05). The MON diet had higher Lag (P < 0.05) in comparison with other treatments. The reduction on lag is related to the increases on dry matter PD for CRINA+MON, CRINA+RUM and CRINA+RUM+P diets, probably because the rumen microorganisms starts the DM degradation earlier, reaching more extension of degradation compared with MON. In conclusion, the use of enzymes (amylase and protease) improves rumen DM degradation. Table 1. Combination of essential oils and exogenous enzymes on in vitro rumen fermentation kinetics

Parameter	MON	CRINA	CRINA+MON	CRINA+RUM	CRINA+RUM+P	P-value	SEM
A	20.16	20.97	19.48	21.79	19.83	0.6986	1.24
B	56.56	57.55	58.22	58.36	58.98	0.7486	1.32
kd	0.0822	0.0687	0.0739	0.0698	0.0723	0.7317	0.0064
Lag	5.34^a	3.74^b	3.07^bc	2.78^bc	2.16^c	0.0025	0.40
PD	76.71^c	78.51^abc	77.70^bc	80.15^a	78.80^ab	0.0700	0.73