Utilization of Cellulolytic Enzymes to Improve the Nutritive Value of Banana Wastes and Performance of Lactating Goats
M.H. Abdel Gawad
An in vitro study was conducted to evaluate the effect of cellulases addition to banana wastes on dry matter (IVDMD) and organic matter (IVOMD) disappearances. Laboratory produced cellulase (Asperozym) and a commercial cellulolytic enzyme source (Bacillozym®) were added separately to banana wastes at 4 levels (0, 0.77, 1.54, 2.31 and 3.08 Unit/kg DM). Increasing the Asperozym levels up to 3.08 U kg-1 DM exhibited the highest (p<0.05) IVDMD and IVOMD, while Bacillozym® recorded the highest (p<0.05) IVDMD and IVOMD values at 1.54 U kg-1 DM compared with the untreated banana wastes (Control). Nine lactating Zaraibi goats (about 3 years old and weight on average 31±0.2 kg) after parturition were divided into three groups of three animals each, using 3x3 Latin square designs to evaluate the effect of Asperozym and Bacillozym® addition to diets on the productivity of lactating goats. Animals were fed on 50% Concentrate Feed Mixture (CFM), 25% banana wastes and 25% berseem (clover) straw (control diet). Control diet+ Asperozym at level of 3.08 U kg-1 DM (T1); control diet+Bacillozym® at level of 1.54 U kg-1 DM. (T2). Apparent digestibility for all nutrients were improved (p<0.05) by cellulases treatments. Milk and 4% Fat Corrected Milk (FCM) yields were higher (p<0.05) for T1 group followed by T2 group than control group while milk composition was not affected (p<0.05). Blood plasma Aspartate aminotransferase (AST) and glucose concentration were not affected by treatments. The addition of Asperozym and Bacillozym® to diets improved the performances of lactating Zaraibi goats with no deleterious effects on general health.
Received: November 04, 2011;
Accepted: February 07, 2012;
Published: May 10, 2012
In some small ruminant production systems, roughages constitute the major portion
of all available feed resources (Kabir et al., 2002;
Hossain et al., 2004). Because of continuously
elevating feed prices, attempts to use new sources of roughages such as banana
wastes had been evaluated by several workers (Khattab et
al., 2000; El-Ashry et al., 2003; Amarnath
and Balakrishnan, 2007).
Each hectare of banana crop generates 13 to 20 tones dry matter/year of plant
residual waste (leaves and pseudostems) that consists mainly of lignocellulose
material (Amarnath and Balakrishnan, 2007). The main
shortcoming of agricultural by-products like banana wastes as a sole ruminant
feed lies in their low protein and high crude fiber content, low digestibility
coefficients and containing some anti-nutrients factors such as tannins and
alkaloids (Kholif et al., 2005; Aritonang,
2009). Thus, to increase digestibility of banana wastes, it is important
to degrade their compact lignocellulytic tissue. There have been attempts to
achieve such objective by biological treatments which could be conducted by
administration of the microbial cells, microbial extracts or microbial enzymes
(Ghorbani et al., 2007; Khadem
et al., 2007; Murad and Azzaz, 2010; Akinyele
et al., 2011; Murad and Azzaz, 2011).
Recent research has demonstrated that supplementing diets of ruminants with
cellulase can improve feed utilization and animal performance by enhancing fiber
degradation in vitro (El-Adawy et al., 2008;
Rodrigues et al., 2008), in situ (Tricarico
et al., 2005; Krueger and Adesogan, 2008)
and in vivo (Gado et al., 2007; Gado
et al., 2009; Khattab et al., 2011).
Also, milk production was increased by adding cellulolytic enzyme preparations
to lactating small ruminants diets (Titi and Lubbadeh,
2004; Stella et al., 2007).
Cellulase with its immense importance is being imported for use in Egypt at a high cost. The local production of such enzymes may reduce the cost of importation and encourages self-reliance.
This study was conducted to, (1) Evaluate potential use of the laboratory produced cellulase in vitro for degradation of banana waste compared with commercial cellulolytic enzyme source, (2) Study effects of adding these cellulolytic enzymes to lactating goat's diets on nutrients digestibility, blood parameters, as well as on milk yield and its composition.
MATERIALS AND METHODS
This study was carried out at the Experimental Farm Station of the Faculty of Agriculture, Cairo University and Dairy Department, National Research Center, Dokki, Giza, Egypt.
Collecting banana wastes: Green banana wastes (leaves and pseudostems) were collected from banana farms after harvesting at Om Dinar, Embaba, Giza province. The wastes were cut and sun-dried, then chopped to 0.5-1 cm and stored in dry place at room temperature until used.
Enzyme sources: Bacillozym®; Product of IBEX International is a commercial cellulolytic enzyme source produced from Bacillus subtilis. Each kg contains 15000 commercial units of cellulase, Bacillus subtilis 0.75x1010 (CFU).
Asperozym; Laboratory produced cellulase from Asperigillus niger. Each kg contains 770 international units (IU) of cellulase. One unit of Asperozym is equivalent to 19.48 unit of Bacillozym®.
Enzymes assay: The carboxymethyl-cellulase activity (CMC) for Bacillozym®
and Asperozym was determined according to Mandels et al.
(1974). The reducing sugar liberated was determined by modified Dinitrosalicylic
acid method (DNS) of Miller (1972). One cellulase unit
is defined as the amount of enzyme that liberates reducing sugar at the rate
of one μmol/mL/min under assay condition.
In vitro study: In vitro dry matter and organic matter
disappearance (IVDMD and IVOMD) was determined for banana waste powder. A 500
mg samples of banana waste powder were weighed into 120 mL serum bottles. The
experimental banana waste (five replicates) was separately supplemented with
rumen liquor, buffer solution and Asperozym and Bacillozym solutions at different
levels (0, 0.77, 1.54, 2.31 and 3.08 U kg-1 DM). Rumen contents were
collected by stomach tube from rams fed berseem hay ration before the morning
feeding, then moved directly to the laboratory in separate warmed oxygen-free
plastic jars. Rumen liquor contents were strained through two layers of cheese-cloth
and the obtained liquor was mixed with the buffer solution at 39°C under
continuous flushing with CO2 using two stage technique according
to method of Norris et al. (1976). Bottles were
sealed with rubber stoppers and incubated at 39°C for 48 h.
Lactation trial: According to results of in vitro trial, the proper dry matter and organic matter disappearances of different levels of Asperozym and Bacillozym® addition, Asperozym at 3.08 U kg-1 DM and Bacillozym® at 1.54 U kg-1 DM were chosen to be used in the lactation trial.
Feeding and management: Nine Zaraibi lactating goats (about 3 years old and weighting on average 31±0.2 kg) after parturition were assigned randomly into three groups of three animals each using 3x3 Latin square design. The experimental periods were 12 weeks (84 days) and consisted of three equal periods (28 day each). The goats were individually fed at 3% of body weight changed continuously according to animal weight changes. The concentrate:roughage ratio was 1:1 on DM basis. The concentrate feed mixture consisted of 60% corn, 20% soybean meal, 15% wheat bran, 3% limestone, 1% minerals and 1% NaCl. The first group was fed on 50% concentrate Feed Mixture (CFM), 25% berseem (clover) straw and 25% banana waste (control diet). The second group was fed control diet+Asperozym at 3.08 U kg-1 DM (T1). The third group was fed control diet+Bacillozym® at 1.54 U kg-1 DM (T2). The concentrate feed mixture was offered once daily at 8.00 a.m., berseem straw and banana waste were offered once daily at 9.00 a.m. The enzymes were introduced to each animal as a capsule before roughage feeding. The control group was getting a capsule free from any enzyme. The chemical composition of feed ingredients is shown in Table 1.
Apparent digestibility: Three digestibility trials were applied during
the last seven days every each experimental period (28 day) using all animals
from each group. Silica was used as an internal marker for determining the digestibility
(Ferret et al., 1999). Four hours after the distribution
of morning meal (09:00 h) feces were collected in cloth bag connected to the
animal back. The collected feces were dried at 55°C for 48 h and then ground
to pass a 1 mm sieve in a feed mill (FZ102, Shanghai Hong Ji instrument Co.,
Ltd., Shanghai, China) for chemical analysis. Dry matter excreted in feces was
calculated by dividing silica input in the feeds (grams of silica per day) by
silica output in the feces (grams of silica per day).
|| Chemical analysis of feed ingredients (on DM basis)
|NDF: Neutral detergent fiber, ADF: Acid detergent fiber, ADL:
Acid detergent lignin, CFM: Concentrate feed mixture consisted of 60% corn,
20% soybean meal, 15% wheat bran, 3% ground limestone, 1% NaCl and 1% Mineral
and vitamin mix contained 42 ppm Co, 3500 ppm Cu, 20,000 ppm Fe, 12,000
ppm Mn, 12, 00 ppm Zn, 1200 ppm I, 3800 IU g-1 of vitamin A,
1200 IU g-1 of vitamin D and 3 IU g-1 of vitamin E
The digestibility coefficient of nutrient was calculated according to the following
formula (Ferret et al., 1999):
Feed and fecal analysis: Feedstuffs and fecal samples were analyzed
according to the AOAC (1995) methods to determine Crude
Protein (CP), Ether Extract (EE), Crude Fiber (CF) and ash contents. Organic
Matter (OM) and Nitrogen Free Extract (NFE) contents were calculated by difference.
The Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) contents were
determined using the methods described by Van Soest et
Blood plasma analysis: Blood samples were collected from the jugular
vein of each animal at the last day of each period (4 h after the 09:00 h feeding).
They were centrifuged at 4000 r.p.m./ 20 min. The plasma was stored at -18°C
till analysis. Plasma was collected and plasma total protein was determined
as described by Armstrong and Carr (1964), albumin (Doumas
et al., 1971), urea (Fawcett and Soctt, 1960),
glucose (Siest et al., 1981) and plasma Aspartate
aminotransferase (AST) and Alanin aminotransferase (ALT) (Reitman
and Frankel, 1957). Globulin and albumin/globulin ratio were calculated.
Sampling and analysis of milk: Animals were milked twice daily at 8.00
a.m. and 4.00 p.m. during the last three days of each experimental period (28
day). Samples of milk were collected immediately from each animal after morning
and evening milking and milk yield was recorded. Milk samples were analyzed
for total solids, fat, true protein and lactose by infrared spectrophotometry
(Foss 120 Milko-Scan, Foss Q3 183 Electric, Hillerød, Denmark) according
to AOAC (1995) procedures. Solids-not-fat (SNF) was calculated.
Fat corrected milk (4% fat) was calculated by using the following equation according
to Gaines (1928):
where, M is milk yield (g) and F is fat yield (g).
Statistical analysis: Data obtained from this study were statistically
analyzed by SAS (1998) as follow:
Latin square design for milk yield and composition, nutrients digestibility
and blood parameters using the general linear model procedure:
where, Yijkl is the parameter under analysis of the ijk goat, μ
is the overall mean, Ri is the effect due to the lactation period
on the parameter under analysis, Cj is the effect due to the animals
on the parameter under analysis, Tk is the effect due to treatment
on the parameter under analysis, eijk is the experimental error for
ijk on the observation. The Duncan's multiple range tests was used to test the
significance between means (Duncan, 1955).
RESULTS AND DISCUSSION
In vitro study: All levels of Asperozym and Bacillozym®
increased (p<0.05) DM and OM disappearance of banana waste compared with
the untreated banana waste (Control), which gave the lowest values of IVDMD
and IVOMD (Table 2). This may be due to that Asperozym and
Bacillozym® were able to degrade complex substrate (cellulose)
to simpler ones which might have altered the structure of banana wastes making
them more amenable to ruminal microorganisms and allowing a faster ruminal microbial
colonization and fermentation. Till now, little is known about the way that
exogenous fibrolytic enzymes improve feed by rumen microorganisms. Several potential
modes of action have been proposed. These include: (a) increase in microbial
colonization of feed particles (Yang et al., 1999)
enhancing attachment and/or improve access to the cell wall matrix by ruminal
microorganisms and by doing so, accelerate the rate of digestion (Nsereko
et al., 2000b) and (c) enhancing the hydrolytic ability of the ruminal
microorganisms due to added enzyme activities and/or synergy with rumen microbial
enzymes (Morgavi et al., 2000). On the other
hand the IVDMD and IVOMD were highest with the highest level of Asperozym (3.08
U kg-1 DM) and Bacillozym® (1.54 U kg-1
DM). This may be related to some different biochemical properties of the experimental
enzymes such as source organism, molecular size, etc. (Vahjen
and Simon, 1999). Also, Eun and Beauchemin (2007)
suggested that the relationship between enzymatic activity and substrate degradation
may depend on the amount of enzymatic activity added or may be due to the different
kinds of enzymes used.
Digestibility and nutritive values: Diets treated with Asperozym (T1)
and Bacillozym® (T2) increased (p<0.05) all nutrients
digestibility and fiber fraction digestibility compared with the control diet
(Table 3). The goats fed (T1) diet showed increase
(p<0.05) most of nutrients digestibility than those fed (T2) diet,
also, the nutritive values of the experimental diets expressed as Total Digestible
Nutrients (TDN) and Digestible Crude Protein (DCP) take the same trend of digestibility
(Table 3). These data in line with Gado
et al. (2009) who reported increase total tract digestibility of
DM, OM and NDF, following treatment with fibrolytic enzymes. The higher values
of CF, NDF, ADF and ADL digestibility of the diets treated with Asperozym or
Bacillozym® compared to the control diet could be attributed
to that Asperozym contains combination of fungal cellulases and; Bacillozym®
contains combination of bacterial cellulases which solubilize fibers and subsequently
may provide some essential nutrients or growth factors to rumen microorganisms.
|| Effect of cellulases on in vitro dry matter and organic
matter disappearance of banana wastes
|1Enzyme efficiency % (DM) = IVDMD% (sample)-IVDMD%
(control) / IVDMD% (control) x100, 2 Enzyme efficiency % (OM)
= IVOMD% (sample) IVOMD% (control) / IVOMD% (control) x100. Each
value of means obtained from five samples. a, b, c and d with different
superscripts in the same column are significantly different (p<0.05)
|| Effects of cellulases on digestion coefficients and nutritive
values of experimental diets fed to goats
|Each value represents an average of six samples, TDN: Total
digestible nutrients, DCP: Digestible crude protein. NDF: Neutral detergent
fiber, ADF: Acid detergent fiber, ADL: Acid detergent lignin, Means in the
same row within each treatment having different superscripts differ significantly
(p<0.05), SE: standard error, T1: control diet+Asperozym at
3.08 U kg-1 DM, T2: control diet+Bacillozym®
at 1.54 U kg-1 DM
|| Effect of cellulases on blood plasma parameters of lactating
goats fed with different experimental diets
|Each value represents an average of eight samples. a, b, c:
Means in the same row within each treatment having different superscripts
differ significantly (p<0.05), SE: Standard error, T1: Control
diet+Asperozym at 3.08 U kg-1 DM, T2: Control diet+bacillozym®
at 1.54 U kg-1 DM, AST: Aspartate amino transferase, ALT: Alanin
Superiority of Asperozym over Bacillozym® for improving apparent
digestibility of treated diets may be due to differences of cellulase type used
and enzyme stability (Nsereko et al., 2000a,
b) reported that variation of responses to fibrolytic
enzymes supplementation could be attributed to the retention time of different
types of fiber in the rumen; exposure time of fiber to the fibrolytic enzymes
process, rate of particle size reduction, particle density and rate of digestion.
Blood plasma parameters: Cellulases treated diets (T1 and
T2) had higher (p<0.05) plasma total protein than those fed the
control diet. This may be attributed to the improvements occurred in metabolic
process as a response to the cellulases additives and indicate that these goats
cover their protein needs. Our finding are in line with those reported by Gado
et al. (2007) who reported that biological treatment (cellulase;
rumen liquor and Cellumonas cellulasea) of bagasse increased plasma total
protein. In addition, plasma albumin, globulin, urea and alanin aminotransferase
(ALT) concentrations were higher (p<0.05) in goats fed (T2) diet
than in those fed control diet (Table 4). This may be due
to a higher organic matter and crude protein (CP) digestibility for these goats
compared with those fed control diet. The variation of plasma urea is in line
with that reported by Gado et al. (2007) who
stated that biological treatment (cellulase; rumen liquor and Cellumonas
cellulasea) of bagasse increased plasma urea concentrations.
|| Effects of cellulases on goat's milk yield and composition
|Each value represents an average of twenty seven samples,
Means in the same row within each treatment having different superscripts
differ significantly (p<0.05), SE: Standard error, T1: Control
diet+asperozym at 3.08 U kg-1 DM, T2: Control diet+Bacillozym®
at 1.54 U kg-1 DM, SNF: Soliels-not-fat
Blood plasma, aspartate aminotransferase (AST) and glucose concentration were
not affected by cellulases treatments. Our results are in line with those obtained
by Kholif (2006) who found that animals fed on fibrolytic
enzymes or fungi treated silage had no significant increase in serum glucose
and AST concentration. The concentrations of ALT and AST were in the normal
range for healthy animals. These results indicated that adding cellulases to
lactating goat's diets were not negatively affected liver activity or animals
Milk yield and composition: Milk composition was not affected by cellulases
treatments, while milk and 4% Fat Corrected Milk (FCM) yields were higher (p<0.05)
for goats fed (T1) and (T2) diets than those fed the control
diet. Goats fed (T1) diet produce more milk than those fed (T2)
diet (Table 5). Adding Asperozym to lactating goat's diets
increased milk production by 18% and fat corrected milk production by 9% , while
adding Bacillozym® to lactating goat's diets increased milk production
by 11% and fat corrected milk production by 8% compared with untreated diets
(control). Our findings are in agreement with the results obtained by Yang
et al. (1999), Titi and Lubbadeh (2004) and
Gado et al. (2009). This response may be attributed
to improved nutrient digestion after cellulases supplementation by goats. Milk
fat and protein yields were higher (p<0.05) for goats fed (T1)
diet than goats fed control diet, reflecting the higher milk yields but goats
fed (T2) diet had higher (p<0.05) milk protein yield but not fat
yield compared with goats fed control diet. It is not clear why the fat and
protein yields of milk were higher when goats were fed cellulases-treated diets
but is likely indirectly related to changes in energy and protein digestion
(Beauchemin et al., 1997). The use of enzyme
additives has been associated with an improved efficiency of synthesis of microbial
protein in the rumen (Jacobs and McAllan, 1992). Therefore,
it is probable that improved efficiency of microbial protein synthesis is a
result of enzyme action on the roughages structural polysaccharides altering
the rate of ruminal degradation of structural carbohydrates (Lewis
et al., 1996) and the provision of a suitable ruminally degradable
nitrogen source (Beauchemin et al., 1999). However,
yield of total solids was significantly increased due to the cumulative effect
of cellulases treatment on the fat and protein concentrations as both were numerically
higher for the treated groups compared to the control group. Milk lactose yield
was higher (p<0.05) for goats fed (T1) and (T2) diets
than those fed the control diet, this could be attributed to the generation
of more nutrients which become available as a result of improvements in feed
digestibility. Specifically, the increase in ruminally fermented OM, which resulted
in a numerical downward shift in the ratio of acetate to propionate, would have
increased delivery of glucogenic precursors to the mammary gland (Yang
et al., 1999).
It could be concluded that Asperozym and Bacillozym® supplementation were more effective for in vitro degradation of banana waste and improve nutrient digestion and milk production by goats fed the experimental diets. Asperozym showed superiority compared with Bacillozym® for improving feed digestion and milk production by Zaraibi goats.
Animal Feeds: Official Methods of Analysis of AOAC International. 16th Edn., Vol. 1, AOAC International, Virginia, USA
Akinyele, B.J., O.O. Olaniyi and D.J. Arotupin, 2011.
Bioconversion of selected agricultural wastes and associated enzymes by Volvariella volvacea
: An edible mushroom. Res. J. Microbiol., 6: 63-70.CrossRef | Direct Link |
Amarnath, R. and V. Balakrishnan, 2007.
Evaluation of the banana (Musa paradisiaca
) plant by-product`s fermentation characteristics to asses their fodder potential. Int. J. Dairy. Sci., 2: 217-225.CrossRef | Direct Link |
Armstrong, W.D. and C.W. Carr, 1964.
Physiological Chemistry Laboratory Direction. 3rd Edn., Burses Publishing Co., Minnesota, USA
Beauchemin, K.A., S.D.M. Jones, L.M. Rode and V.J.H. Sewalt, 1997.
Effects of fibrolytic enzymes in corn or barley diets on performance and carcass characteristics of feedlot cattle. Can. J. Anim. Sci., 77: 645-653.
Beauchemin, K.A., W.Z. Yang and L.M. Rode, 1999.
Effects of grain source and enzyme additive on site and extent of nutrient digestion in dairy cows. J. Dairy Sci., 82: 378-390.CrossRef | Direct Link |
Doumas, B.T., W.A. Watson and H.G. Biggs, 1971.
Albumin standards and the measurement of serum albumin with bromcresol green. Clin. Chim. Acta, 31: 87-96.CrossRef | PubMed | Direct Link |
Duncan, D.B., 1955.
Multiple range and multiple F tests. Biometrics, 11: 1-42.CrossRef | Direct Link |
El-Adawy, M.M., A.Z.M. Salem, B.E. Borhami, H.M. Gado, M.S. Khalil and A. Abo-Zeid, 2008. In vitro
cecal gas production and dry matter degradability of some browse leaves in presence of enzymes from anaerobic bacterium in NZW rabbit. Proceedings of the 9th WRSA World Rabbit Congress, June 10-13, Verona, Italy, pp: 643-647Direct Link |
El-Ashry, M.A., A.M. Kholif, M. Fadel, H.A. El-Alamy and H.M. El-Sayed, 2003.
Effect of biological treatments on chemical composition and in vitro
and in vivo
digestibilities of poor quality roughages. Egypt. J. Nutr. Feeds, 6: 113-126.
Eun, J.S., and K.A. Beauchemin, 2007.
Assessment of the efficacy of varying experimental exogenous fibrolytic enzymes using in vitro
fermentation characteristics. Anim. Feed Sci., Technol., 132: 298-315.CrossRef |
Ferret, A., J. Plaixats, G. Caja, J. Gasa and P. Prio, 1999.
Using markers to estimate apparent dry matter digestibility, faecal output and dry matter intake in dairy ewes fed Italian ryegrass hay or alfalfa hay. Small Rumin. Res., 33: 145-152.CrossRef | Direct Link |
Gado, H.M., A.Z.M. Salem, P.H. Robinson and M. Hassan, 2009.
Influence of exogenous enzymes on nutrient digestibility, extent of ruminal fermentation as well as milk production and composition in dairy cows. Anim. Feed Sci. Technol., 154: 36-46.CrossRef | Direct Link |
Gado, H.M., H.M. Metwally, H. Soliman, A.Z.L. Basiony and E.R. El-Galil, 2007.
Enzymatic treatments of bagasse by different sources of cellulase enzymes. Conf. Animal Nutr., 10: 607-613.
Gaines, W.L., 1928.
The energy basis of measuring milk yield in dairy cows. Bulletin No. 308, University of Illinois at Urbana-Champaign, Champaign, IL., USA., May 1928, pp: 403-438.
Ghorbani, G.R., A. Jafari, A.H. Samie and A. Nikkhah, 2007.
Effects of applying exogenous, non-starch polysaccharidases to pre-weaning starter concentrate on performance of holstein calves. Int. J. Dairy. Sci., 2: 79-84.CrossRef | Direct Link |
Hossain, S.M.J., M.R. Alam, N. Sultana, M.R. Amin and M.M. Rashid, 2004.
Milk production from indigenous black Bengal goat in Bangladesh. J. Biological Sci., 4: 262-265.CrossRef | Direct Link |
Jacobs, J.L. and A.B. McAllan, 1992.
Protein supplementation of formic acid- and enzyme-treated silages. 2. Nitrogen and amino acid digestion. Grass Forage Sci., 47: 114-120.CrossRef | Direct Link |
Kabir, F., M. Shahjalal, S.A. Chowdhury, J. Alam and M.R. Islam, 2002.
Effect of protein supplementation to grazing on growth and reproductive performance in female goats and sheep. Pak. J. Biol. Sci., 5: 719-721.CrossRef | Direct Link |
Khadem, A.A., M. Pahlavan, A. Afzalzadeh and M. Rezaeian, 2007.
Effects of live yeast Saccharomyces cerevisiae
on fermentation parameters and microbial populations of rumen, total tract digestibility of diet nutrients and on the in situ
Degradability of alfalfa hay in Iranian Chall sheep. Pak. J. Biol. Sci., 10: 590-597.CrossRef | PubMed | Direct Link |
Khattab, H.M., A.M. Kholif, H.A. El-Alamy, F.A. Salem and A.A. El-Shewy, 2000.
Ensiled banana wastes with molasses or whey for lactating buffaloes during early lactation. Asian-Australasian J. Anim. Sci., 13: 619-624.CrossRef | Direct Link |
Khattab, H.M., H.M. Gado, A.E. Kholif, A.M. Mansour and A.M. Kholif, 2011.
The potential of feeding goats sun dried rumen contents with or without bacterial inoculums as replacement for berseem clover and the effects on milk production and animal health. Int. J. Dairy Sci., 6: 267-277.CrossRef | Direct Link |
Kholif, A.M., M.A. El-Ashry, H.A. El-Alamy, H.M. El-Sayed, M. Fadel and S.M. Kholif, 2005.
Biological treatments banana wastes for feeding lactating goats. Egypt. J. Nutr. Feeds, 8: 149-162.
Kholif, S.M., 2006.
Effect of improving the nutritional value of poor quality roughages on the yield and composition of goat's milk. Egypt. J. Dairy Sci., 34: 197-205.
Krueger, N.A. and A.T. Adesogan, 2008.
Effect of different mixtures of fibrolytic enzymes on the digestion and fermentation of bahiagrass hay. Anim. Feed Sci. Technol., 145: 84-94.Direct Link |
Lewis, G.E., C.W. Hunt, W.K. Sanchez, R. Treacher, G.T. Pritchard and P. Feng, 1996.
Effect of direct-fed fibrolytic enzymes on the digestive characteristics of a forage-based diet fed to beef steers. J. Anim. Sci., 74: 3020-3028.PubMed | Direct Link |
Mandels, M., L. Hontz and J. Nystrom, 1974.
Enzymatic hydrolysis of waste cellulose. Biotechnol. Bioeng., 16: 1471-1493.CrossRef | Direct Link |
Miller, G.L., 1972.
Use of dinitrosalicyclic acid reagent for determination of reducing sugar. Biotechnol. Bioeng. Symp., 5: 193-219.
Morgavi, D.P., K.A. Beauchemin, V.L. Nsereko, L.M. Rode and A.D. Iwaasa et al
Synergy between ruminal fibrolytic enzymes and enzymes from Trichoderma longibrachiatum
. J. Dairy Sci., 83: 1310-1321.CrossRef | Direct Link |
Murad, H.A. and H.H. Azzaz, 2010.
Cellulase and dairy animal feeding. Biotechnology, 9: 238-256.CrossRef | Direct Link |
Murad, H.A. and H.H. Azzaz, 2011.
Microbial pectinases and ruminant nutrition. Res. J. Microbiol., 6: 246-269.CrossRef | Direct Link |
Norris, K.H., R.F. Barnes, J.E. Moore and J.S. Shenk, 1976.
Predicting forage quality by infrared reflectance spectroscopy. J. Anim. Sci., 43: 889-897.
Nsereko, V.L., D.P. Morgavi, K.A. Beauchemin and L.M. Rode, 2000.
Inhibition of ruminant feed enzyme polysaccharidase activities by extracts from silages. Can. J. Anim. Sci., 80: 523-526.Direct Link |
Nsereko, V.L., D.P. Morgavi, L.M. Rode, K.A. Beauchemin and T.A. McAllister, 2000.
Effects of fungal enzyme preparations on hydrolysis and subsequent degradation of alfalfa hay fiber by mixed rumen microorganisms in vitro
. Anim. Feed Sci. Technol., 88: 153-170.CrossRef | Direct Link |
Reitman, S. and S. Frankel, 1957.
A colorimetric method for the determination of serum glutamic oxalacetic and glutamic pyruvic transaminases. Am. J. Clin. Pathol., 28: 56-63.CrossRef | PubMed | Direct Link |
Rodrigues, M.A.M., P. Pinto, R.M.F. Bezerra, A.A. Dias and C.V.M. Guedes et al
Effect of enzyme extracts isolated from white-rot fungi on chemical composition and in vitro
digestibility of wheat straw. Anim. Feed Sci. Technol., 141: 326-338.CrossRef | Direct Link |
Aritonang, S.N., 2009.
The effect of forage energy level on production and reproduction performances of Kosta female goat. Pak. J. Nutr., 8: 251-255.CrossRef | Direct Link |
Statistical Analysis System User's Guide. SAS Institute Inc., Cary, NC
Siest, G., J. Henny and F. Schiele, 1981.
Interpretation Des Examens Laboratories. Karger, Switzerland, pp: 206-223
Stella, A.V., R. Paratte, L. Valnegri, G. Cigalino and G. Soncini et al
Effect of administration of live Saccharomyces cerevisiae on milk production, milk composition, blood metabolites and faecal flora in early lactating dairy goats. Small Rumin. Res., 67: 7-13.CrossRef | Direct Link |
Titi, H.H. and W.F. Lubbadeh, 2004.
Effect of feeding cellulase enzyme on productive responses of pregnant and lactating ewes and goats. Small Rumin. Res., 52: 137-143.CrossRef | Direct Link |
Tricarico, J.M., J.D. Johnston, K.A. Dawson, K.C. Hanson, K.R. McLeod and D.L. Harmon, 2005.
The effects of an Aspergillus oryzae
extract containing alpha-amylase activity on ruminal fermentation and milk production in lactating Holstein cows. Anim. Sci., 81: 365-374.CrossRef | Direct Link |
Vahjen, W., and O. Simon, 1999.
Biochemical characteristics of non starch polysaccharide hydrolyzing enzyme preparations designed as feed additives for poultry and piglet nutrition. Arch. Anim. Nutr., 52: 1-14.PubMed | Direct Link |
Van Soest, P.J., J.B. Robertson and B.A. Lewis, 1991.
Methods for dietary fiber, neutral detergent fiber and nonstarch polysaccharides in relation to animal nutrition. J. Dairy Sci., 74: 3583-3597.CrossRef | PubMed | Direct Link |
Yang, W.Z., K.A. Beauchemin and L.M. Rode, 1999.
Effects of an enzyme feed additive on extent of digestion and milk production of lactating dairy cows. J. Dairy Sci., 82: 391-403.CrossRef | PubMed | Direct Link |
Fawcett, J.K. and J.E. Scott, 1960.
A rapid and precise method for the determination of urea. J. Clin. Pathol., 13: 156-159.CrossRef | PubMed | Direct Link |