Evaluation of rations supplemented with fibrolytic enzyme on dairy cows performance. In situ ruminal degradability of different feedstuffs

This experiment was conducted to study the effect of fibrolytic enzymes supplementation on in situ degradability of DM, CP and CF of different feedstuffs included concentrate feed mixture (CFM), berseem hay (BH), dried sugar beet tops (DSBT), corn silage (CS), rice straw (RS) and wheat straw (WS). The fibrolytic enzyme (fibrozyme) was added to the ground feedstuffs at the levels of 0, 1 and 1.5 g/kg DM diluted with distilled water (1:10 w/v) and sprayed with 10 ml per kg of ground feedstuffs overnight and samples incubated in canulated multiparous Friesian cows for 2, 4, 8, 16, 24, 48 and 72 hours.

Concentrate feed mixture showed the highest values of DM, CP and CF disappearance followed by DSBT, while both RS and WS had the lowest values (P<0.05). Moreover, the added fibrozyme at the level of 1 g/kg showed the highest in situ ruminal DM and CF disappearance for CFM and DSBT and CP disappearance for CFM, BH and DSBT, while the level of 1.5 g/kg recorded the highest DM and CF disappearance for BH, CS, RS and WS and CP disappearance for CS, RS and WS. The DSBT showed the highest rapid degradable fraction (a), CS the highest potential degradable fraction (b), CFM had the highest degradation rate (c) and RS and WS had the highest undegradable fraction (u) for both DM and CP (P<0.05). While, CFM showed the highest rapid degradable fraction (a), CS recorded the highest potential degradable fraction (b), CFM had the highest degradation rate (c), but RS and WS showed the highest undegradable fraction (u) for CF (P<0.05). Moreover, CFM showed the highest outflow rate of degradable DM at 2, 5 and 8%/ hour from the rumen for DM, CP and CF, but both RS and WS had the lowest values. Fibrozyme added at the level of 1 g/kg showed the highest in situ ruminal DM and CF degradation for CFM and DSBT and CP degradation for CFM, BH and DSBT, while the level of 1.5 g/kg recorded the highest DM and CF degradation for BH, CS, RS and WS and CP degradation for CS, RS and WS.

Introduction

Forages are the major and cheapest source of energy for ruminants. Improvement in forage fiber digestion increases the energy available to ruminants. During the last decade, the use of exogenous fibrolytic enzymes to enhance fiber digestion has been investigated. Several studies using enzyme additives have reported improvements in digestion in vitro (Lewis et al 1996, Colombatto 2000, Hristov et al 2000, Bowman et al 2002, Kung et al 2002) and feed utilization in vivo (Lewis et al 1996, Schingoethe et al 1999, Yang et al 1999).

In a recent study, 23 commercial enzyme products were examined for enzyme activity and in vitro feed degradation. Five of these products significantly improved the 18-h degradation of alfalfa hays, and nine of them improved degradation of maize silage (Colombatto et al 2002a,b). However, other studies (Sheperd and Kung 1996, Vicini et al 2003) showed enzyme application did not improve animal performance. Beauchemin et al (2001) concluded that results concerning the effects of enzyme addition to ruminant diets on animal performance are variable and responses to some commercial enzyme products can be contradictory.

These reports suggest that effects of exogenous enzyme treatment of forages are inconsistent due to enzyme type, concentration, diet type and application method, and more detailed knowledge of exogenous enzyme interaction with feed, host and rumen micro-organisms is necessary to apply this technology successfully (Morgavi et al 2000). Many studies with forages treated with enzymes have examined responses after ensiling. Few data are available involving application of mixture enzymes to forage that is not subsequently ensiled. Specifically, research is needed to examine the effects of exogenous mixture enzymes applied to dry forages used in ruminant diets. The enzymes selected for this study have only previously been used in poultry.

The objective of the present study was to investigate the effect of fibrolytic enzyme (Fibrozyme) additive on in situ ruminal DM, CP, CF degradability of different feedstuffs.

Materials and methods

The experimental work of this study was conducted at Sakha Animal Production Research Station, Animal Production Research Institute (APRI), Agricultural Research Center, Ministry of Agriculture in co-operation with the Department of Animal Production, Faculty of Agriculture, Kafrelsheikh University during the period from July to November 2008.

This trial was conducted to study the effect of fibrozyme additive on in situ ruminal degradability of DM, CP and CF of different feedstuffs concluded concentrate feed mixture (CFM), berseem hay (BH), dried sugar beet tops (DSBT), corn silage (CS), rice straw (RS) and wheat straw (WS).

Fibrolytic enzyme (fibrozyme) ingredients are Aspergillus Niger, Trchodema Longibrchiatum, fermentation extracts and fermentation soluble. Also, it contains 20% CP, 8% ash and 100 U xylanase / g (International Free Trade Co., Cairo, Egypt). The fibrozyme were added to the ground feedstuff at the levels of 1 and 1.5 g/kg DM. The fibrozyme was diluted with water at 100 and 150 g/liter for the levels of 1 and 1.5 g/kg, respectively and sprayed with 10 ml per kg of ground feedstuffs overnight according to the procedure stated by Kung et al (2000).

Three multiparous Friesian cows were used for studying degradability of the different feedstuffs in a 3×3 Latin Square Design. The ruminal degradability of DM, CP and CF for three samples of different feedstuffs were determined by in situ technique (Mehrez and Ørskov 1977). Samples of different feedstuffs were ground and 5 gm weighed into 7x12 cm nylon bags with mean pore size 50 µm, bags were tied near the end of 60 cm nylon cord anchored by a 70 gm steel weight and incubated in the rumen (in triplicate for each silage) for different extends times (0, 2, 4, 8, 16, 24, 48 and 72 hrs). Zero hour bags were washed to estimate the disappearance due to both solubility and washing procedure. The bags after incubation in the rumen were also washed. All bags then dried at 60 ^oC for 48 hrs to determine DM. The results of DM, CP and CF disappearance were fitted to the following exponential models of Ørskov and McDonald (1979) and the degradation was calculated by using the NAWAY computer programme with the following exponential model: P = a + b (1 - e^-ct): Where, P = percentage disappearance at time t. a = rapidly soluble fraction. b = slowly degradable fraction. a + b = potential degradability. c = fractional rate constant at which b will be degraded. t = time. u = undegradable fraction. Effective degradability of DM, CP and CF were calculated using the rumen outflow rate (K), P and the constants a, b and c from the above model. K was assumed to be 0.02, 0.05 or 0.08 per h. Effective degradability (ED) in the rumen was calculated as ED = a + [(bx c)/(c + k)] where a is the water soluble fraction, b is the potentially degradable (insoluble) fraction, c is the degradation rate of b, and k is the fractional passage rate out of the rumen.

The representative samples of the different feedstuffs before and after incubation were chemically analyzed for DM, CP, CF, EE and ash determinations according to the official methods of AOAC (1990). Fiber constituents, neutral detergent fiber (NDF) was determined according to Van Soest and Marcus (1964). While, acid detergent fiber (ADF) and acid detergent lignin (ADL) was determined according to Van Soest (1963).

The obtained data were subjected to statistical analysis using general linear models procedure adapted by SPSS (2008) for user’s guide with one-way ANOVA. Duncan test within program SPSS was done to determine the degree of significance between the means (Duncan 1955).

Results and discussion

Chemical composition of tested feedstuffs:

Table 1. Chemical composition of tested feedstuffs
Item	CFM*	BH	DSBT	CS	RS	WS
DM %	91.5	89.9	90.1	33.9	91.6	92.0
Composition of DM %:
OM	91.8	85.6	76.1	92.3	82.8	86.0
CP	16.1	13.5	14.5	8.75	3.01	2.17
CF	12.3	31.3	12.3	26.3	35.7	39.5
EE	2.98	2.25	1.76	2.56	1.25	1.16
NFE	60.5	38.7	47.5	54.7	42.8	43.2
Ash	8.52	14.4	23.9	7.69	17.3	14.0
Fiber fractions %:
NDF	26.9	46.8	32.1	55.4	74.6	76.5
ADF	12.3	27.2	13.4	28.4	44.9	46.5
ADL	3.76	4.83	2.30	5.20	3.12	5.78
* CFM consisted of 32% undecorticated cotton seed cake, 24% wheat bran, 22% yellow corn, 12% rice bran, 5% linseed cake, 3%molasses, 1% limestone and 1% common salt

The composition revealed many variations among the different feedstuffs. DM content in corn silage (CS) was low, while OM content in dried sugar beet tops (DSBT) was low. The CP content was medium in CS and low in rice (RS) and wheat (WS) straws, but CF, NDF and ADF contents were low in concentrate feed mixture (CFM) and DSBT compared with RS and WS. The EE content was medium in DSBT and low in both of RS and WS. The NFE content was high in CFM and CS. Ash content was low in CFM and CS and high in DSBT. These results agreed with those obtained by Sallam (2005) who found that the highest value of NDF, ADF and ADL were observed in rice straw.

In situ ruminal degradability

Table 2. In situ ruminal DM disappearance (%) of different feedstuffs
Enzyme level	Incubation times, hours
Enzyme level	0	2	4	8	16	24	48	72
Concentrate feed mixture (CFM)
0	27.9^c	34.4^c	40.2^b	49.8^b	63.1^b	71.2^b	81.0^b	83.2^b
1	31.6^a	38.8^a	45.1^a	55.6^a	70.4^a	78.7^a	88.1^a	90.2^a
1.5	28.9^b	37.1^b	44.2^a	55.4^a	69.7^a	78.2^a	87.3^a	88.8^a
Mean	29.5^B	36.8^B	43.2^A	53.6^A	67.7^A	76.0^A	85.5^A	87.4^A
Berseem hay (BH)
0	16.9^c	23.1^c	27.7^b	33.7^c	43.8^b	52.0^c	67.8^b	74.9^b
1	21.0^b	24.4^b	28.8^a	35.2^b	45.5^b	53.3^b	68.2^b	76.3^ab
1.5	22.8^a	26.1^a	29.3^a	38.3^a	52.1^a	60.7^a	72.0^a	77.4^a
Mean	20.2^C	24.5^C	28.6^B	35.7^C	47.1^C	55.3^C	69.3^C	76.2^B
Dried sugar beet tops (DSBT)
0	34.3^b	38.4^b	42.0^b	48.3	52.8^b	58.1^b	75.2	76.6^b
1	40.4^a	42.0^a	44.1^a	49.6	58.4^a	65.2^a	76.3	81.2^a
1.5	40.0^a	41.1^a	43.5^ab	48.5	53.4^b	58.6^b	75.8	79.1^ab
Mean	38.2^A	40.5^A	43.2^A	48.8^B	54.9^B	60.6^B	75.8^B	79.0^B
Corn silage (CS)
0	10.9^c	12.6^c	16.9^c	22.3^c	32.1^b	38.8^b	53.9^b	63.6^b
1	15.5^b	17.8^b	20.1^b	24.4^b	32.3^b	40.3^ab	57.6^a	71.3^a
1.5	17.7^a	20.0^a	22.2^a	26.4^a	34.2^a	41.1^a	59.6^a	73.0^a
Mean	14.7^D	16.8^D	19.7^C	24.4^D	32.9^D	40.1^D	57.0^D	69.3^C
Rice straw (RS)
0	3.9	6.2^b	8.2^c	14.0^c	19.0^c	25.1^c	39.6^c	49.6^c
1	4.4	8.3^a	14.1^b	17.5^b	23.7^b	29.2^b	42.5^b	52.4^b
1.5	4.8	9.1^a	16.0^a	19.9^a	27.3^a	33.2^a	47.4^a	55.9^a
Mean	4.4^E	7.9^E	12.8^D	17.1^E	23.3^E	29.2^E	43.2^E	52.6^D
Wheat straw (WS)
0	3.0^b	4.5^c	6.5^c	9.9^c	16.2^c	22.2^c	37.5^c	50.2^c
1	3.5^ab	11.5^b	13.8^b	18.2^b	25.5^b	31.8^b	45.1^b	52.8^b
1.5	3.8^a	13.2^a	15.5^a	19.9^a	27.6^a	34.1^a	47.7^a	55.6^a
Mean	3.4^E	9.7^E	11.9^D	16.0^E	23.1^E	29.4^E	43.4^E	52.9^D
a, b, c: Values in the same column for each item with different superscripts differ significantly (P<0.05) A, B, C, D, E: Means in the same column with different superscripts differ significantly (P<0.05)

Concentrate feed mixture (CFM) showed significantly (P<0.05) the highest values of DM disappearance followed by DSBT, while both RS and WS had the lowest values. Moreover, added fibrozyme at the level of 1g/kg recorded the highest percentages of in situ DM disappearance for CFM and DSBT, while the level of 1.5 g/kg showed the highest percentages of in situ DM disappearance for BH, CS, RS and WS at the different incubation times. So, the level of added fibrozyme should be increased with increasing the fiber content of feedstuffs. The results also showed a positive correlation between DM disappearance and NFE content (r = 0.31), while there was a negative correlation between DM disappearance and CF content (r = - 0.57). The differences in DM disappearance among the different feedstuffs might be due to the differences in chemical composition as shown in Table 1. These results are in accordance with those obtained by Hoffman et al (1993) who stated that legumes exhibited more extensive ruminal DM degradation than did grasses. Feng et al (1996) and Giraldo et al (2008) reported that fibrolytic enzymes improves in situ DM digestibility. Gaafar et al (2008) found that enzyme treated corn stover silage increased in situ DM disappearance. Eweedah (2007) who found that DM disappearance increased with increasing NFE content and found the DSPT recoded the highest DM disappearance value due to the lower CF content.

The effects of fibrozyme on the degradation fractions and effective degradability of DM at different out flow rate for different feedstuffs are presented in Table 3.

Table 3. Ruminal degradation and effective degradability (%) of DM for different feedstuffs
Enzyme level	Effective degradability				Degradation fractions
Enzyme level	a	b	c	u	K=0.02	K=0.05	K=0.08
Concentrate feed mixture (CFM)
0	27.8^b	55.9^b	0.06	16.3^a	70.2^b	58.5^b	52.3^b
1	31.6^a	60.3^a	0.07	8.1^b	76.7^a	64.9^a	58.0^a
1.5	30.6^a	59.8^a	0.07	9.6^b	74.5^a	64.7^a	57.7^a
Mean	29.8^B	58.7^BC	0.07^A	11.5^CD	73.8^A	62.7^A	56.0^A
Berseem hay (BH)
0	16.9^c	59.1^b	0.03^b	24.0^a	58.2^c	43.8^c	37.4^c
1	21.0^b	63.7^a	0.03^b	15.3^b	59.4^b	45.2^b	38.9^b
1.5	22.8^a	64.2^a	0.06^a	13.0^b	60.6^a	48.1^a	41.3^a
Mean	20.2^C	62.3^B	0.04^B	17.5^B	59.4^C	45.7^C	39.2^C
Dried sugar beet tops (DSBT)
0	32.7^b	57.8	0.02^b	9.5	64.9	53.7^b	49.5^b
1	34.3^a	58.3	0.05^a	7.4	66.8	65.5^a	51.2^a
1.5	32.7^b	58.3	0.02^b	9.0	65.7	54.2^b	50.2^ab
Mean	33.2^A	58.1^BC	0.03^C	8.7^D	65.8^B	57.8^B	50.3^B
Corn silage (CS)
0	10.6^b	70.2^b	0.02	19.2^a	47.0^b	33.1	26.4^c
1	12.6^a	71.3^ab	0.02	16.1^ab	50.4^a	33.4	27.7^b
1.5	12.7^a	73.2^a	0.02	14.1^b	51.3^a	33.6	29.6^a
Mean	12.0^D	71.6^A	0.02^D	16.4^BC	49.6^D	33.4^D	27.9^D
Rice straw (RS)
0	4.1^b	49.0^c	0.01	46.9^a	33.6^c	20.1^c	15.1^c
1	4.5^ab	58.2^ba	0.02	37.3^b	37.4^b	24.8^b	20.2^b
1.5	5.8^a	65.4^a	0.02	28.8^c	40.5^a	28.0^a	23.0^a
Mean	4.8^F	57.5^C	0.02^D	37.7^A	37.2^E	24.3^E	19.4^E
Wheat straw (WS)
0	8.9^c	54.7	0.01	36.4^a	33.5^c	18.1^c	13.0^c
1	9.1^b	55.5	0.02	35.4^b	37.9^b	25.9^b	21.0^b
1.5	10.7^a	56.2	0.02	33.1^b	40.4^a	28.1^a	23.0^a
Mean	9.6^E	55.5^C	0.02^D	34.9^A	37.3^E	24.0^E	19.0^E
a, b, c: Values in the same column for each item with different superscripts differ significantly (P<0.05) A, B, C, D, E, F: Means in the same column with different superscripts differ significantly (P<0.05)

The DSBT showed the highest rapid degradable fraction (a) followed by CFM, while RS had the lowest value (P<0.05). CS recorded the highest potential degradable fraction (b) followed by BH, while WS had the lowest value (P<0.05). CFM had the highest degradation rate (c) followed by BH, while CS, RS and WS had the lowest values (P<0.05). However, RS and WS showed the highest undegradable fraction (u) followed by BH, while DSBT had the lowest value (P<0.05). Moreover, CFM showed the highest outflow rate of degradable DM at 2, 5 and 8%/ hour from the rumen followed by DSBT, while RS and WS had the lowest values (P<0.05).

Fibrozyme treated feedstuffs led to increase in the rapid and potential degradable fractions, degradation rate and the outflow rate of degradable DM at 2, 5 and 8%/ hour from the rumen and decrease in the undegradable fraction (P<0.05). The highest rapid and potential degradable fractions, degradation rate and the outflow rate of degradable DM at 2, 5 and 8%/ hour from the rumen and the lowest undegradable fraction recorded with added fibrozyme at the level of 1g/kg for CFM and DSBT and at the level of 1.5g/kg for BH, CS, RS and WS (P<0.05). These results agreed with those obtained by Jallilvand et al (2008) who found that forages showed different DM rumen degradation kinetics. Gaafar et al (2008) reported that enzyme treated corn stover silage increased degradation fractions and outflow rates of DM in the rumen. For DM, enzyme treatment significantly (p<0.01) increased the rapidly soluble fraction a, the potentially degradable fraction b, and effective degradability (Jalilvand et al 2008).

Crude protein disappearance

Table 4. In situ ruminal CP disappearance (%) of different feedstuffs
Enzyme level	Incubation times (hours)
Enzyme level	0	2	4	8	16	24	48	72
Concentrate feed mixture (CFM)
0	26.9	35.7^b	42.7^b	54.1^c	69.3^b	78.1^c	85.9^b	87.9^b
1	28.0	36.9^a	45.2^a	57.8^a	72.7^a	80.9^a	89.4^a	90.9^a
1.5	27.7	36.9^a	44.5^a	56.7^b	72.4^a	80.0^b	87.9^ab	89.8^ab
Mean	27.5^A	36.2^A	44.1^A	56.2^A	71.5^A	79.7^A	87.7^A	89.5^A
Berseem hay (BH)
0	13.7	20.0^b	25.5^b	34.7^b	49.0^b	59.0^b	74.1^b	78.0^b
1	15.0	20.8^a	26.2^a	35.8^a	50.7^a	60.5^a	75.5^a	80.5^a
1.5	14.5	20.2^b	25.8^ab	35.7^a	50.1^a	60.1^a	74.6^b	80.0^a
Mean	14.4^B	20.3^C	25.8^C	35.4^C	49.9^C	59.9^C	74.7^C	79.5^C
Dried sugar beet tops (DSBT)
0	26.5^c	31.8^b	36.6^b	44.9^b	57.1^b	64.9^c	76.3^b	79.5^b
1	29.7^a	34.8^a	39.6^a	48.0^a	62.7^a	68.4^a	78.4^a	82.5^a
1.5	29.1^b	34.6^a	39.5^a	47.5^a	60.3^ab	67.2^b	78.3^a	81.6^a
Mean	28.4^A	33.7^B	38.6^B	46.8^B	60.0^B	66.8^B	77.7^B	81.2^B
Corn silage (CS)
0	7.1^b	10.4^c	13.7^b	19.9^b	31.0^b	40.5^b	61.9^c	75.3
1	9.2^a	12.6^b	16.0^a	22.5^a	33.8^a	43.2^a	63.4^b	75.6
1.5	9.5^a	13.0^a	16.4^a	22.9^a	34.2^a	43.8^a	64.1^a	75.9
Mean	8.6^C	12.0^D	15.4^D	21.8^D	33.0^D	42.5^D	63.1^D	75.6^D
Rice straw (RS)
0	1.0^b	3.3^b	5.5^c	9.8^c	17.7^c	25.0^c	43.2^c	57.0^c
1	2.1^a	6.9^a	10.0^b	15.0^b	24.4^b	32.3^b	49.9^b	60.9^b
1.5	2.4^a	7.7^a	10.9^a	16.2^a	25.8^a	34.0^a	52.1^a	63.6^a
Mean	1.8^D	6.0^E	8.8^E	13.7^E	22.6^E	30.4^E	48.4^E	60.5^E
Wheat straw (WS)
0	0.7^b	3.2^b	6.7^b	10.8^b	18.6^b	26.7^b	45.2^b	59.0
1	1.8^a	5.0^a	7.2^ab	11.8^b	19.8^b	27.1^b	45.5^b	59.4
1.5	2.6^a	5.0^a	8.9^a	15.7^a	23.2^a	37.7^a	53.0^a	60.8
Mean	1.7^D	4.4^F	7.6^E	12.8^E	20.5^F	30.5^E	47.9^E	59.7^E
a, b, c: Values in the same column for each item with different superscripts differ significantly (P<0.05) A, B, C, D, E, F: Means in the same column with different superscripts differ significantly (P<0.05)

Concentrate feed mixture (CFM) showed the highest values of in situ CP disappearance followed by DSBT, while both RS and WS had the lowest values (P<0.05). Moreover, the level of added fibrozyme 1 g/kg showed the highest percentages of in situ CP disappearance for CFM, BH and DSBT, while the level of 1.5 g/kg recorded the highest percentages of in situ CP disappearance for CS, RS and WS (P<0.05). The results also showed a positive correlation between CP disappearance and CP content (r = 0.64). These results are in accordance with Eweedah (2007) who reported that the CP disappearance was lower for CS than BH and DSPT at incubation period. Gaafar et al (2008) found that enzyme treated corn stover silage increased In Situ CP disappearance.

The effect of fibrozyme on the degradation fractions and effective degradability of CP for different feedstuffs are presented in Table 5.

Table 5. Ruminal degradation and effective degradability (%) of CP for different feedstuffs
Enzyme level	Effective degradability				Degradation fractions
Enzyme level	a	b	c	u	K=0.02	K=0.05	K=0.08
Concentrate feed mixture (CFM)
0	26.9	59.8^c	0.07^b	13.3^a	75.9^b	63.8^b	56.5^b
1	28.0	64.5^b	0.09^a	7.5^c	78.0^a	66.0^a	58.7^a
1.5	27.7	63.2^a	0.07^b	9.1^b	76.1^b	65.5^a	58.7^a
Mean	27.5^A	62.5^D	0.08^A	10.0^C	76.7^A	65.1^A	58.0^A
Berseem hay (BH)
0	13.4^b	66.1^b	0.05	20.5^a	61.1^b	46.5^b	38.7
1	15.0^a	68.4^a	0.04	16.6^b	62.3^a	47.4^a	39.6
1.5	14.5^a	68.3^a	0.05	17.2^b	61.5^b	47.0^a	38.7
Mean	14.3^B	67.6^C	0.05^B	18.1^B	61.6^C	47.0^C	39.0^C
Dried sugar beet tops (DSBT)
0	26.5^c	53.4	0.05	20.1^a	65.7^c	54.1^c	47.7^b
1	29.7^a	54.6	0.05	15.7^b	68.8^a	57.4^a	50.9^a
1.5	29.1^b	54.4	0.05	16.5^b	67.9^b	56.5^b	50.1^a
Mean	28.4^A	54.1^E	0.05^B	17.4^B	67.5^B	56.0^B	49.6^B
Corn silage (CS)
0	7.1^b	83.0	0.02	9.9^a	51.8^c	32.4c	24.6^c
1	9.0^a	83.5	0.02	7.5^ab	52.7^b	34.5^b	27.0^b
1.5	9.4^a	84.0	0.02	6.6^b	53.3^a	35.0^a	27.5^a
Mean	8.5^C	83.5^A	0.02^C	8.0^D	52.6^D	34.0^D	26.4^D
Rice straw (RS)
0	1.0^b	68.2^c	0.01	30.8^a	37.3^c	19.6^c	13.5^c
1	1.0^b	70.5^b	0.01	28.5^ab	41.3^b	25.2^b	18.8^b
1.5	1.2^a	71.2^a	0.01	27.6^b	43.3^a	26.8^a	20.2^a
Mean	1.1^D	70.0^B	0.01^D	28.9^A	40.6^E	23.9^E	17.5^E
Wheat straw (WS)
0	1.1^c	66.7^b	0.01	32.2^a	36.9^b	19.2^b	13.2^b
1	3.0^b	67.1^b	0.01	29.9^ab	39.7^a	22.1^a	15.8^a
1.5	3.3^a	69.3^a	0.01	27.4^b	39.9^a	22.3^a	16.8^a
Mean	2.5^D	67.7^C	0.01^D	29.8^A	38.8^F	21.2^F	15.3^F
a, b, c: Values in the same column for each item with different superscripts differ significantly (P<0.05) A, B, C, D, E, F: Means in the same column with different superscripts differ significantly (P<0.05)

The DSBT showed the highest rapid degradable fraction (a) followed by CFM, while RS had the lowest value (P<0.05). CS recorded the highest potential degradable fraction (b) followed by RS, while DSBT had the lowest value (P<0.05). CFM had the highest degradation rate (c) followed by BH and DSBT, while RS and WS had the lowest values (P<0.05). However, RS and WS showed the highest undegradable fraction (u), but CS recorded the lowest value (P<0.05). Moreover, CFM showed the highest outflow rate of degradable CP at 2, 5 and 8%/ hour from the rumen followed by DSBT, while WS had the lowest values (P<0.05).

Fibrozyme treated feedstuffs led to increase in the rapid and potential degradable fractions, degradation rate and the outflow rate of degradable CP at 2, 5 and 8%/ hour from the rumen and decrease in the undegradable fraction. The level of 1 g/kg showed the highest values for CFM, BH and DSBT, while the level of 1.5 g/kg recorded the highest values for CS, RS and WS. These results agreed with those obtained by Eweedah (2007) who reported that the CP degradability increase as the period of incubation prolonged and the degradability of N was consistently greater than DM. Jallilvand et al (2008) found that the soluble CP fraction a was higher for both alfalfa hay and maize silage than for wheat straw, whereas the potentially fermentable fraction b was higher for maize silage than for the other forages and parameter c for alfalfa hay was significantly higher than for the other forages. Gaafar et al (2008) reported that enzyme treated corn stover silage increased degradation fractions and outflow rates of DM in the rumen. Many factors influence the ruminal degradability of forage CP content such as stage of maturity, forage species and preservation method (Hoffman et al 1993).

Table 6. In situ ruminal CF disappearance (%) of different feedstuffs
Enzyme level	Incubation times (hours)
Enzyme level	0	2	4	8	16	24	48	72
Concentrate feed mixture (CFM)
0	28.3^c	36.4^b	42.0^b	51.0^b	63.5^b	71.3^b	76.5^c	77.2^b
1	33.2^a	39.4^a	44.2^a	53.8^a	66.4^a	74.0^a	83.4^a	85.6^a
1.5	30.7^b	36.7^b	43.2^ab	53.5^a	65.7^a	71.7^b	80.9^b	83.2^b
Mean	30.7^A	37.5^A	43.1^A	52.8^A	65.2^A	72.3^A	80.3^A	82.0^A
Berseem hay (BH)
0	11.5^b	18.0^b	24.0^b	34.1^b	48.9^b	58.8^b	72.9	76.7^b
1	11.9^b	18.4^b	24.1^b	34.3^b	49.4^b	59.3^b	73.0	77.2^ab
1.5	15.0^a	21.4^a	27.7^a	37.9^a	52.8^a	64.3^a	74.1	78.2^a
Mean	12.8^C	19.3^C	25.3^C	35.4^C	50.4^C	60.8^B	73.3^B	77.4^B
Dried sugar beet tops (DSBT)
0	25.5^b	30.4^b	34.9^c	41.5^b	49.6^c	56.2^c	69.0^c	74.7^b
1	31.2^a	34.1^a	38.0^a	44.9^a	55.6^a	63.3^a	75.4^a	79.7^a
1.5	29.9^a	34.0^a	36.6^b	42.6^b	53.8^b	61.2^b	71.6^b	75.6^b
Mean	28.9^B	32.8^B	36.5^B	43.0^B	53.0^B	60.2^B	72.0^B	76.7^B
Corn silage (CS)
0	9.9^b	12.3^b	14.6^b	19.0^c	27.2^c	34.5^b	52.4^c	65.4^b
1	11.0^a	13.6^a	16.0^a	20.5^b	28.9^b	36.3^c	53.7^b	65.7^b
1.5	11.1^a	13.7^a	16.3^a	21.2^a	30.3^a	38.2^a	56.9^a	69.8^a
Mean	10.7^D	13.2^D	15.6^D	20.2^D	28.8^D	36.3^C	54.3^C	67.0^C
Rice straw (RS)
0	4.3^b	6.7^b	9.0^c	13.4^c	21.0^c	28.0^c	43.1^c	52.7^c
1	5.7^a	8.2^a	10.6^b	15.1^b	23.2^b	30.1^b	45.4^a	55.0^b
1.5	5.8^a	9.2^a	12.0^a	17.4^a	26.6^a	34.2^a	50.0^b	58.8^a
Mean	5.3^E	8.0^F	10.5^F	15.3^F	23.6^F	30.8^D	46.2^E	55.5^D
Wheat straw (WS)
0	5.4^c	7.8^c	10.1^c	14.4^c	21.9^c	28.7^c	44.3^b	53.6^b
1	6.9^b	9.9^b	12.8^b	18.2^b	27.1^b	34.1^b	47.4^b	54.3^b
1.5	8.5^a	11.6^a	14.6^a	20.0^a	29.2^a	36.3^a	56.7^a	56.8^a
Mean	6.9^E	9.8^E	12.5^E	17.5^E	26.1^E	33.0^D	49.5^D	54.9^D
a, b, c: Values in the same column for each item with different superscripts differ significantly (P<0.05) A, B, C, D, E, F: Means in the same column with different superscripts differ significantly (P<0.05)

Concentrate feed mixture (CFM) showed the highest values of CF disappearance followed by DSBT, while both RS and WS had the lowest values (P<0.05). Moreover, the addition of fibrozyme at the level of 1 g/kg resulted in increase the percentage of in situ CF disappearance for CFM and DSBT, while the level of 1.5 g/kg recorded the highest values for BH, CS, RS and WS at the different incubation times (P<0.05). The CF disappearance for different feedstuffs increased with increasing NFE content (r = 0.26), however it decreased with increasing CF content (r = - 0.48). The differences in CF disappearance among the different feedstuffs might be due to the differences in chemical composition as shown in Table 1. These results agreed with those obtained by Gaafar et al (2008) who found that enzyme treated corn stover silage increased in situ CF disappearance. Eweedah (2007) found that the higher CF content was associated with lower its in situ ruminal disappearance.

The effect of fibrozyme on the degradation fractions and effective degradability of CF for different feedstuffs are shown in Table 7.

Table 7. Ruminal degradation and effective degradability (%) of CF for different feedstuffs
Enzyme level	Effective degradability				Degradation fractions
Enzyme level	a	b	c	u	K=0.02	K=0.05	K=0.08
Concentrate feed mixture (CFM)
0	28.3^c	49.0^b	0.06^b	22.7^a	68.4^c	59.7^b	53.5^b
1	33.2^a	53.2^a	0.09^a	13.6^b	73.0^a	62.5^a	56.3^a
1.5	30.7^b	53.1^a	0.06^b	16.2^b	70.6^b	59.8^b	54.3^b
Mean	30.7^A	51.8^D	0.07^A	17.5^D	70.7^A	60.7^A	54.7^A
Berseem hay (BH)
0	11.3^b	63.6^b	0.05	25.1^a	59.8^b	45.5^b	37.8^b
1	12.0^b	67.1^a	0.05	20.9^ab	60.6^ab	45.6^b	37.8^b
1.5	14.8^a	67.3^a	0.05	17.9^b	61.8^a	48.4^a	40.9^a
Mean	12.7^C	66.0^B	0.05^B	21.3^C	60.7^B	46.5^C	38.8^C
Dried sugar beet tops (DSBT)
0	25.8^b	50.5	0.05^a	23.7^a	61.0^b	49.6^c	44.5^c
1	31.2^a	54.7	0.04^ab	14.1^b	65.5^a	53.9^a	48.0^a
1.5	30.2^a	52.7	0.02^b	17.1^ab	61.8^b	51.1^b	45.2^b
Mean	29.1^B	52.6^D	0.04^C	18.3^CD	62.8^B	51.5^B	45.9^B
Corn silage (CS)
0	9.9^b	82.1	0.01^b	8.0^a	45.9^c	30.3^c	22.9^c
1	11.1^a	83.6	0.02^a	5.3^ab	49.2^b	45.9^b	24.3^b
1.5	11.1^a	84.9	0.02^a	4.0^b	64.6^a	49.2^a	25.2^a
Mean	10.7^D	83.5^A	0.02^E	5.8^E	53.2^C	41.8^D	24.1^D
Rice straw (RS)
0	4.4^b	64.1	0.02	31.5^a	36.0^c	22.1^c	16.7^c
1	5.7^a	65.3	0.02	29.0^ab	38.0^b	24.0^b	18.5^b
1.5	6.2^a	65.7	0.02	28.1^b	41.1^a	26.9^a	20.7^a
Mean	5.4^E	65.0^B	0.02^E	29.5^B	38.4^E	24.3^F	18.6^F
Wheat straw (WS)
0	5.4^c	53.4^b	0.02^b	41.2^a	38.3^c	23.5^c	17.7^c
1	6.9^b	54.8^b	0.03^a	38.3^a	40.1^b	26.8^b	21.4^b
1.5	8.5^a	63.0^a	0.03^a	28.5^b	43.6^a	28.8^a	22.9^a
Mean	6.9^E	57.1^C	0.03^D	36.0^A	40.7^D	26.4^E	20.7^E
a, b, c: Values in the same column for each item with different superscripts differ significantly (P<0.05) A, B, C, D, E: Means in the same column with different superscripts differ significantly (P<0.05)

CFM showed the highest rapid degradable fraction (a) followed by DSBT, while RS and WS had the lowest value (P<0.05). CS recorded the highest potential degradable fraction (b) followed by BH and RS, while CFM had the lowest value (P<0.05). CFM had the highest degradation rate (c) followed by BH, while CS and RS had the lowest values (P<0.05). However, WS showed the highest undegradable fraction (u) followed by RS, while CS had the lowest value (P<0.05). Moreover, CFM showed the highest outflow rate of degradable DM at 2, 5 and 8%/ hour from the rumen followed by DSBT, while RS and WS had the lowest values (P<0.05).

Fibrozyme treated feedstuffs led to increase in the rapid and potential degradable fractions, degradation rate and the outflow rate of degradable CF at 2, 5 and 8%/ hour from the rumen and decrease in the undegradable fraction (P<0.05). The enzyme level of 1g/kg showed the highest rapid and potential degradable fractions, degradation rate and the outflow rate of degradable DM at 2, 5 and 8%/ hour from the rumen and the lowest undegradable fraction for CFM and DSBT, while the level of 1.5 g/kg revealed the highest values for BH, CS, RS and WS (P<0.05). These results are in agreement with those obtained by Gaafar et al (2008) who reported significant increased degradation fractions and outflow rates of CF in the rumen with enzyme treated corn stover silage. Also, Pirmohammadi et al (2006) reported that the higher CF degradation when treated the forage with fibrolytic enzyme.

Conclusion

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Evaluation of rations supplemented with fibrolytic enzyme on dairy cows performance. In situ ruminal degradability of different feedstuffs

M I Bassioun, H M A Gaafar, M S Saleh, A M A Mohi El-Din and M A H Elshora*

Department of Animal Production, Faculty of Agriculture, Kafrelsheikh University, Egypt.
hamedgaafar@gmail.com
Animal Production Research Institute, Agricultural Research Center, Dokki, Giza, Egypt.

Abstract

Introduction

Materials and methods

Results and discussion

Chemical composition of tested feedstuffs:

In situ ruminal degradability

Crude protein disappearance

Conclusion

References

Evaluation of rations supplemented with fibrolytic enzyme on dairy cows performance. In situ ruminal degradability of different feedstuffs

M I Bassioun, H M A Gaafar*, M S Saleh, A M A Mohi El-Din* and M A H Elshora*

Department of Animal Production, Faculty of Agriculture, Kafrelsheikh University, Egypt. hamedgaafar@gmail.com Animal Production Research Institute, Agricultural Research Center, Dokki, Giza, Egypt.

Abstract

Introduction

Materials and methods

Results and discussion

Chemical composition of tested feedstuffs:

In situ ruminal degradability

Crude protein disappearance

Conclusion

References

M I Bassioun, H M A Gaafar, M S Saleh, A M A Mohi El-Din and M A H Elshora*

Department of Animal Production, Faculty of Agriculture, Kafrelsheikh University, Egypt.
hamedgaafar@gmail.com
Animal Production Research Institute, Agricultural Research Center, Dokki, Giza, Egypt.