Effects of exogenous fibrolytic enzymes on in sacco and in vitro degradation of diets and on growth performance of lambs

Figures & data

Table 1 Ingredients and chemical composition of experimental diets.

Enzyme (g/kg DM)
Control (0 g)		Low (3 g)	High (6 g)
Ingredients, % DM
Corn grain, ground	30.0	30.0	30.0
Sorghum grain, ground	28.1	27.7	27.4
Soybean meal, 44% CP	10.9	10.9	10.9
Alfalfa hay	15.0	15.0	15.0
Corn stover	15.0	15.0	15.0
Mineral premix^*	1.0	1.0	1.0
Enzyme°	0.3	0.6
Chemical composition
Dry matter, %	88.0	88.9	89.1
Crude protein, % DM	14.4	14.6	13.9
Neutral detergent fibre, % DM	34.0	33.9	33.6
Acid detergent fibre, % DM	12.0	12.8	12.5
Ash, % DM	5.0	5.7	5.8

* DM base: selenium 10 mg/kg; potassium 215 mg/kg; iron 50 mg/kg; cobalt 20 mg/kg; zinc 50 mg/kg; manganese 1600 mg/kg; copper 300Mg/kg; iodine 70 mg/kg; calcium 220 mg/kg; phosphorus 280 mg/kg; sulphur 30 g/kg; salt 950 g/kg.

° Fibrozyme, Alltech Inc., Nicholasville, KY, USA.

Table 2 Effect of fibrolytic enzymes on kinetics of ruminal in vitro gas production of dry Matter fermentation.

		Enzyme (g/kg DM)
	Control (0 g)	Low (3 g)	High (6 g)	SEM	Polynomial
Parameters of kinetic^*
V, mL/100 mg DM	42.6	43.5	43.1	0.59	ns
L, h	0.05	0.19	0.48	0.12	Linear
R, %/h	0.039	0.043	0.047	0.001	Linear
At 48 h fermentation^°
Degradation, %	73.6	73.9	76.5	0.44	Quadratic
Acetate, %	26.7	26.9	27.5	2.81	ns
Propionate, %	11.1	12.5	12.1	0.62	Quadratic
Butyrate, %	8.7	7.6	7.5	0.40	Quadratic
Total VFA, %	46.5	47.0	47.1	3.58	ns
A:P ratio	2.4	2.2	2.3	0.18	ns
Ammonia, N mg/L	250.2	244.8	221.9	23.22	Linear

* V, total gas produced; L, initial duration of initial gas volume; R, gas production rate.

° A:P, acetate propionate ratio. SEM, standard error of the mean.

Figure 1 Effect of fibrolytic enzymes on in sacco disappearance (ISD) of dry matter and neutral detergent fibre of high concentrate diets.

Table 3 Effect of fibrolytic enzymes on kinetics of ruminal in sacco disappearance.

		Enzyme (g/kg DM)
	Control (0 g)	Low (3 g)	High (6 g)	SEM	Polynomial
Dry matter, %
Soluble fraction a	22.4	21.9	22.3	1.82	ns
Potential disappearance b	51.3	51.0	52.0	3.29	ns
Total disappearance a + b	73.7	72.9	74.3	3.97	ns
Disappearance rate c,%/h	2.9	3.0	3.3	0.11	Quadratic
Neutral detergent fibre, %
Potential disappearance b	44.1	43.6	44.4	3.34	ns
Disappearance rate c, %/h	3.6	3.5	3.7	0.29	ns

SEM, standard error of the mean.

Table 4 Effect of fibrolytic enzymes in lambs.

		Enzyme (g/kg DM)
	Control (0 g)	Enzyme (3 g)	SEM
Initial BW, kg	17.6	17.1	0.32
Final BW, kg	35.8	35.5	0.61
Total gain, g	18.2	18.4	0.38
Average daily gain, ADG, g	216.2	218.6	2.91
Dry matter intake, DMI, g/d	919.9	921.1	7.48
Feed conversion, DMI/ADG	4.3	4.2	0.13

SEM, standard error of the mean; BW, body weight.