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Vol. 8(2), pp. 23-31, February, 2014
DOI: 10.5897/AJPAC2013.0532
ISSN 1996 - 0840 ©2014 Academic Journals
http://www.academicjournals.org/AJPAC
African Journal of Pure and Applied
Chemistry
Full Length Research Paper
Studies on urea treated rice milling waste and its
application as animal feed
Simon Terver Ubwa*, James Abah, Barnabas Atsinafe Oshido and Esther Otokpa
Department of Chemistry, Benue State University, P. M. B 102119, Makurdi, Nigeria.
Accepted 17 January, 2014
The composition of urea treated rice milling waste and its application as animal feed was studied. The
proximate analysis of the urea treated rice milling waste showed that it contained 94.90% dry matter,
10.38% crude protein, 5.89% crude fibre, 0.16% ether extract, 7.47% ash, and 54.81% nitrogen-free
extracts. The untreated rice milling waste contained 94.34% dry matter, 9.11% crude protein, 6.37%
crude fibre, 0.18% ether extract, 8.11% ash, and 54.69% nitrogen-free extracts. Four experimental diets
were prepared containing two different levels (30 and 35%) each of untreated and urea treated rice
milling waste mixed with commercial pelletized chick mash to assess their effects on weaner rabbits.
Data on the feed intake, growth rate, and feed conversion ratio (FCR) of weaner rabbits fed diets
containing two different levels each of untreated and urea treated rice milling waste were compared
using two-way analysis of variance (ANOVA). There were no significant effects (P > 0.05) of dietary
treatment and level of inclusion for average feed intake, average body weight gain, and the FCR. The
study indicated that rabbits can be successfully raised on a commercial chick mash mixed with 35%
rice milling waste treated or untreated without any adverse effect on growth.
Key words: Rice milling waste, weaner rabbit, proximate analysis, analysis of variance, animal feed, urea.
INTRODUCTION
Rice milling waste is one of the commonest agro-
industrial wastes generated in large quantities in most
parts of Nigeria. Rice processing generates a great
volume of by-products that constitute a large proportion
of agro-industrial waste in many parts of the world
(NAERLS and PCU, 2004). Although, one can hardly
classify rice milling waste among hazardous wastes, its
treatment is very important in view of the great volume of
waste materials involved. Waste treatment techniques
are normally employed to alter the physical, chemical, or
biological characteristics of waste and make it safer for
disposal. These include composting, pyrolysis,
gasification, and combustion. In Nigeria and many other
developing countries, where the bulk of rice produced is
for consumption, the most common waste treatment
technique employed is combustion which has several
disadvantages including environmental pollution
(Thipwimon et al., 2004; Bhattacharya et al., 1999).
Moreover, some countries under the environmental
protection legislation now strongly oppose and even
prohibit this practice.
Rice milling waste is believed to contain various
nutrients that would enable it to serve as animal feed.
The major challenges are however, its high level of fibre
and low protein and energy. Studies have shown that the
nutritional value of rice milling waste can be significantly
improved by processing/treatment techniques such as
mechanical treatment, ensilage, biological treatment, and
*Corresponding author. E-mail: drsimonterverubwa@gmail.com. Tel: +2347036704880.
24 Afr. J. Pure Appl. Chem.
chemical treatment with alkalis and urea (Belewu and
Babalola, 2009; MacDonald et al., 1987a) since urea
treatment increases rice milling waste utilization and fibre
fraction degradation .In developed countries, the by-
products of the rice industry are separated into different
components and converted into value-added products. In
Nigeria, however, these by-products are largely dumped
together. The quantity of rice milling by-products
generated in Nigeria annually was estimated at about
1,032,993.6 metric tons (NAERLS and PCU, 2004). A
large amount of these by-products is dumped as waste
thereby posing disposal problems and bringing about
methane emissions (Thipwimon et al., 2004;
Bhattacharya et al., 1999). The disposal problems posed
by rice milling waste have led to indiscriminate burning of
the waste and subsequent accumulation of ash in rice
producing areas resulting in environmental pollution and
loss of land. Rice milling waste can also cause
respiratory problems due to its characteristics
(Thipwimon et al., 2004; Beagle, 1978).
The problems associated with rice milling waste can be
greatly reduced if the waste can be effectively utilized as
animal feed. Effective utilization of rice milling waste as
animal feed has not been possible and reports have
shown that the major constraints to this utilization include
low crude protein, energy and mineral content (Belewu
and Babalola, 2009; MacDonald et al., 1987b; Maikano,
2007; Yakubu et al., 2007). However, some research
findings indicated that rice milling wastes contain
moderate level of crude protein, and also have low crude
fibre and high metabolizable energy (Crampton and
Harris, 1969; Ambasankar and Chandrasekan, 2002;
Singh and Marwaha, 1968). Crude fibre consists of
cellulose, hemicelluloses and lignin (Yakubu et al., 2007)
which are not well utilized by monogastric animals (Amdt
et al., 1980). Lignin, which envelopes some nutrients, is
highly resistant to chemical and enzymatic degradation
and is poorly degraded by rumen microbes (Belewu and
Babalola, 2009; MacDonald et al., 1987a). Strong
chemical bonds exist between lignin and many plant
polysaccharides and cell wall proteins, which render
these compounds unavailable during digestion. These
bonds are however, broken by chemical treatment
thereby increasing the digestibility of fibrous feeds
(Belewu and Babalola, 2009; MacDonald et al., 1987b;
Rexen and Vestergaard, 1976). Among the chemicals
that have been utilized, sodium hydroxide has proven to
be the most effective in improving digestibility but lacks
nitrogen. Furthermore, there is increased sodium load in
animals fed with diets treated with sodium hydroxide
(Adeniji, 2010). Another effective chemical that has been
used successfully in achieving this is ammonia, which
weakens the hard cell walls, allowing better penetration
by rumen microorganisms to produce more effective
fermentation and liberation of nutrients (Chenost, 1995).
In developing countries like Nigeria, one of the more
successful procedures available to improve the digestibility
and therefore nutritional value of fibrous feeds is urea
treatment since this requires little equipment or
expenses, even subsistence farmers can apply urea
treatment. Chemical treatment of rice milling waste with
urea can lead to significant improvement in nutritional
quality and therefore greater utilization (Taiwo et al.,
1992). The effective utilization of rice milling waste as
animal feed will greatly reduce its disposal problems and
contributes towards value addition in the rice sector. This
research was therefore designed to study the urea
treated rice milling waste and its application as animal
feed.
MATERIALS AND METHODS
Rice milling waste collection
The sample was obtained from Naka rice processing industry waste
dump 25 km from Makurdi, Benue State, Nigeria. Random sampling
technique was employed to collect samples of the waste taken at
depths of 10 cm from different points using a clean plastic container
and shovel. The sub-samples were pooled together, mixed
thoroughly and packed into an empty 10 kg polyethene bags which
were conveyed to animal laboratory.
Sources of feed and experimental animals
The rice milling waste was obtained from Naka rice processing
industry dumpsite along Makurdi road. 5.0kg of urea (fertilizer
grade) was purchased from a certified dealer. The experimental
animals (16 weaned rabbits) were purchased at the University of
Agriculture Quest House, Makurdi. A small quantity (2 kg) of
commercial chick mash was obtained from a certified dealer at
Wurukum, Makurdi and fed to the rabbits before the experiment
began. 25 kg of the commercial feed was later obtained at Asaba,
Delta State and used for the experimental feed preparation. The
experiment was conducted at the Federal College of Education
(Technical) Asaba, in the animal unit using a metabolic cage
constructed under the supervision of certified animal scientist and
biochemist.
Sample treatment
The rice milling waste was treated by dissolving 2.5 kg of urea in 50
dm3 of water and applied to 50 kg of rice milling waste. The treated
rice milling waste was placed in a plastic container and made
airtight by covering it with polyethene sheets and the container’s lid.
It was then allowed to ferment for 3 weeks after which it was
removed and sun dried for several days (Adeniji, 2010; Sundstol
and Coxworth, 1984). A portion of the rice milling waste was left
untreated and used for the control experiment.
Feed preparation
Four diets (Diets 1, 2, 3, and 4) were prepared by thoroughly mixing
the rice milling waste samples and the commercial pelletized chick
mash in different ratios. Diet 1 contained 30% urea treated rice
milling waste and 70% commercial diet, Diet 2 contained 30%
untreated rice milling waste and 70% commercial diet, Diet 3
contained 35% untreated rice milling waste and 65% commercial
diet while Diet 4 contained 35% urea treated rice milling waste and
Ubwa et al. 25
Table 1. Chemical composition of urea treated and untreated rice milling waste.
Parameter
Components (%)
DM
CP
CF
EE
Ash
NFE
UTRMW
94·90
10.38
5·89
0.16
7.47
54.81
UNTRMW
94·34
9.11
6·37
0.18
8.11
54.69
UTRMW = Urea treated rice milling waste; UNTRMW = untreated rice milling waste; DM = dry matter;
CP = crude protein; CF = crude fibre, EE = ether extract; NFE = nitrogen-free extracts.
65% commercial diet. Diets 2 and 3 served as the first and second
control (2 for Diet 1 and 3 for Diet 4), respectively.
Experimental animals design and diets
In this experiment, 16, weaned, mixed breeds male rabbits of age
28 days were used. The rabbits were kept for a week and fed with
commercial diet and fresh potato (Ipomoea batatas) leaves under
laboratory conditions. They were then fed with the experimental
diets for an adaptation period of 2 weeks. During this period, no
data on feed intake and body weight was recorded. The rabbits
weighed between 530 and 560 g when the experiment started. The
rabbits were randomly assigned to four treatment diets with four
rabbits per treatment after balancing for body weight. The rabbits
were housed in a metabolic cage constructed and partitioned with
wood and wire gauze.
The cage was raised above the ground to allow for separation of
urine and faeces. The animals were fed twice daily (morning and
evening). Clean water was provided ad libitum and Anupco Vitalyte
Extra (a combination of vitamins, electrolyte, and amino acids),
Embazin-forte (anticoccidial with vitamin K) and Neotreat WSP
(antibiotics and vitamins) were added to the water at intervals and
according to the manufacturer’s prescription throughout the
experimental period of 9 weeks.
Data collection
The animals were weighed when the experiment started and then
once weekly during the growth period. The weekly body weights
were determined by weighing the animals individually. This was
usually done early in the morning prior to feeding. The quantity of
feed offered as well as the leftover was weighed each day to
determine the daily intake. The daily feed consumption was
recorded as the quantity of feed served minus the leftover. Data on
feed intake, weight gain, and feed conversion ratio (FCR) were
computed. Nutrient digestibility study was done on the 9th week of
the experiment.
Digestibility study
The faeces were collected individually during 4 consecutive days.
The faecal samples from each experimental unit were bulked, sun
dried, and analysed for proximate composition.
Proximate analysis
The proximate compositions of the treated and untreated rice waste
samples as well as the faecal samples were determined according
to official methods of analysis (AOAC, 1980). All samples were
ground to pass a 1-mm sieve prior to analysis.
RESULTS AND DISCUSSION
Chemical composition of urea treated and untreated
rice milling waste
The results of the chemical compositions of the urea
treated and the untreated rice milling waste are
presented in Table 1.
Chemical composition of diets
The result of the chemical compositions of the
experimental diets is presented in Table 2.
Feed intake of weaner rabbits
The results of the weekly average feed intake (g) of the
weaner rabbits fed with different levels of untreated and
urea treated rice milling waste based diets are presented
in Table 3. The average feed intakes were comparable
among the four groups of rabbits.
Weekly weight of weaner rabbits
The result of the average weekly live weight (g) of
weaner rabbits fed with the experimental diets is
presented in Table 4.
Performance of the weaner rabbits fed with the
experimental diets
The performance of the weaner rabbits fed with varying
levels of rice milling waste based diets is shown in Table
5.
Feed intake
The feed conversion ratio was calculated as:
Weight gain
Coefficients of digestibility of nutrients were determined
according to the formula:
[(quantity of feed × nutrients of feed) – (quantity of faeces × nutrients of faeces)] × 100
(Quantity of feed × nutrients of feed)
26 Afr. J. Pure Appl. Chem.
Table 2. Chemical composition of the experimental diets.
Component (%)
Diet 1
Diet 2 (T1)
Diet 3 (T2)
Diet 4
Dry matter
96.20
96.07
96.37
96.27
Crude protein
15.71
15.33
14.89
15.33
Crude fibre
5·97
6·26
6·13
6·11
Ether extract
6.00
6.00
5.59
5.59
Ash
3.85
4.11
4.33
4.04
NFE
59.28
59.25
58.92
58.96
T1 = Control 1; T2 = Control 2; NFE = Nitrogen-free extracts.
The nutritive compositions of the urea treated and
untreated rice milling waste are presented in Table 1. The
results showed that the both feedstocks have comparable
nutrient profile although the urea treated rice milling
waste had a higher crude protein value (10.38%) than the
untreated rice milling waste (9.11%). This suggests that
urea treatment increased the crude protein content of rice
milling waste. The treatment of rice milling waste with
urea increased its nitrogen content due to the addition of
non-protein nitrogen. This collaborate the reports of other
studies that urea ammoniation increases the crude
protein content of feed materials (Yakubu et al., 2007;
Ambaye, 2009; Amaefule et al., 2003, 2006; Oluokun,
2005). The percentage increase in crude protein
(13.94%) due to urea treatment in this study is lower than
the values reported by Yakubu et al. (2007) and Ambaye
(2009). This may be attributed to the higher content of
crude protein in the original material. The crude protein
value of 9.11% for the untreated rice milling waste is
within the range, 7.8 and 9.4% reported by Ambasankar
and Chandrasekan (2002) and Crampton and Harris
(1969), respectively. It is however, higher than the 5.03,
5.83, and 6.00% previously reported by Maikano (2007),
Yakubu et al. (2007), and Aduku (2004). The crude fibre
content of the urea treated rice milling waste was slightly
lower than that of the untreated rice milling waste. The
reduction in crude fibre content of the urea treated rice
milling waste is in agreement with the report of Yakubu et
al. (2007). The crude fibre value of 6.37% obtained in this
present study is higher than the 0.96% reported by
Ambasankar and Chandrasekan (2002) and 3.14%
reported by Singh and Marwaha (1968) but much lower
than the 30.39, 42.15, and 33.00% obtained by Maikano
(2007), Yakubu et al. (2007), and Aduku (2004),
respectively. The dry matter, ether extract, ash, and
nitrogen-free extract values are 94.90, 0.16, 7.47, and
54.81% for the urea treated rice milling waste and 94.34,
0.18, 8.11 and 54.69% for the untreated rice milling
waste, respectively. The urea treated rice milling waste
had slightly higher dry matter and nitrogen-free extract
contents but lower ether extract and ash contents than
the untreated rice milling waste. The dry matter content of
the untreated rice milling waste in this study was quite
similar to that (94.42%) published by Maikano (2007) but
higher than the 89.50 and 90.53% previously reported by
Yakubu et al. (2007) and Ambasankar and
Chandrasekan (2002), respectively. Maikano (2007),
Yakubu et al. (2007), Ambasankar and Chandrasekan
(2002), and Aduku (2004) reported ether extract values of
rice milling waste of 3.40, 6.45, 3.20, and 5.60% and
Maikano (2007), Yakubu et al (2007), and Aduku (2004)
reported ash content of 16.67, 21.76 and 19.10%,
respectively. The rice milling waste used in the present
study contained considerably less ether extract and ash.
The nitrogen-free extract (54.69%) obtained in this
experiment was higher than the 46.10 and 30.05%
reported by Maikano (2007) and Yakubu et al. (2007),
respectively but considerably lower than the value
(85.26%) reported by Aduku (2004). The variations
between the proximate compositions of different rice
milling waste have been attributed to the rice variety,
growing conditions, pre-treatment before milling, milling
system, degree of milling, and the proportion of husk
(Saunders, 1990; Farell, 1994).
The proximate compositions of the experimental diets
(Table 2) showed that the four dietary treatments have
comparable nutrient compositions. The dry matter
content of the four dietary treatments ranged from 96.07
to 96.37%, crude protein ranged from 14.89 to 15.71%,
crude fibre ranged from 5.97 to 6.26%, ether extract
ranged from 5.59 to 6.00%, ash ranged from 3.85 to
4.33%, and nitrogen-free extract ranged from 58.92 to
59.28%. The comparable nutrient compositions of the
experimental feed may be attributed to the initial quality
of the treated material. It has been reported that the
effect of urea treatment is more pronounced for materials
whose initial quality is very poor compared to those with
better original quality (Chenost, 1995).
The result of the average daily feed intake of the
weaner rabbits from Week 1 to 8 is shown in Table 3.
The average daily intake did not follow any defined
pattern. The least average daily intake (61.65 ± 11.34 g,
57.29 ± 10.32 g, 55.65 ± 3.76, and 58.57 ± 13.45 g for
Diets 1, 2, 3, and 4, respectively) was recorded in Week
1. The highest average daily intake recorded (79.68 ±
14.10 g, 76.29 ± 22.36 g, 67.35 ± 12.01 g, and 75.45 ±
Ubwa et al. 27
Table 3. Weekly average feed intake (g) of the weaner rabbits fed with different levels of
untreated and urea treated rice milling waste based diets.
Week
Diet 1
Diet 2
Diet 3
Diet 4
1
61.65 ± 11.34
57.29 ± 10.32
55.65 ± 3.76
58.57 ± 13.45
2
65.15 ± 6.07
61.96 ± 16.01
58.24 ± 6.73
60.75 ± 12.49
3
79.68 ± 14.10
76.29 ± 22.36
65.71 ± 10.18
75.45 ± 9.32
4
66.86 ± 12.20
63.57 ± 13.45
60.35 ± 5.59
62.14 ± 12.20
5
64.65 ± 9.51
62.05 ± 11.67
64.09 ± 8.70
65.10 ± 8.00
6
70.45 ± 11.10
68.55 ± 6.55
63.70 ± 11.32
69.15 ± 13.25
7
75.39 ± 7.69
71.93 ± 9.65
67.35 ± 12.01
74.65 ± 11.30
8
67.26 ± 10.12
63.28 ± 13.00
61.30 ± 7.07
63.45 ± 9.78
Total
551.29 ± 22.65
524.92 ± 18.56
496.39 ± 13.17
529.26 ± 23.50
Values measured as mean ± standard deviation, n = 7.
Table 4. Average weekly weight per diet (g) of the weaner rabbits fed with treated diets.
Average weight (g)
Diet 1
Diet 2
Diet 3
Diet 4
Initial weight
550.00
555.00
540.00
540.00
Week 1
665.00
662.00
638.00
641.00
Week 2
776.00
798.00
760.00
761.00
Week 3
895.00
900.00
875.00
867.00
Week 4
1021.00
1020.00
1000.00
1002.00
Week 5
1161.00
1151.00
1137.00
1145.00
Week 6
1303.00
1295.00
1284.00
1284.00
Week 7
1456.00
1444.00
1434.00
1429.00
Week 8
1616.00
1601.00
1580.00
1584.00
Weekly average
133.25 ± 18.63
130.75 ± 19.75
130.00 ± 18.25
130.50 ± 19.42
Values measured as mean weight of four animals, except for weekly average, which equals Mean ± standard
deviation of eight measurements.
9.32 g for animals on Diets 1, 2, 3, and 4, respectively
was on different weeks.
The average daily feed intake (Table 5) of the rabbits
fed with the four treatment diets, D1, D2, D3, and D4 (in
grams) for the experimental period of eight weeks are
68.89, 65.62, 62.05, and 66.16, respectively. The rabbits
fed with diets containing urea treated rice milling waste
(D1 and D4) consumed more feed than those fed with
diets containing untreated rice milling waste (D2 and D3).
The trend of the average daily feed intake showed that
D1 > D4 > D2 > D3. The higher feed intake of animals on
D1 and D4 may be due to urea treatment, which is
believed to increase intake (Preston and Leng, 1987).
The higher intake however, did not result in better growth
performance of rabbits. The 2-way analysis of variance
(ANOVA) result of Tests of Between-Subjects Effects
[TBSE (Table 6)] showed no significant main effect (P >
0.05) of treatment and level of inclusion. There was also
no significant interaction effect between the treatment
and level of inclusion (P > 0.05). The parallel lines of the
marginal means in the profile plot (Figure 1) further
illustrate the non-significant interaction effect.
The average weekly weight gains of the experimental
rabbits per treatment diet are recorded in Table 4. The
TBSE result (Table 7) indicated that average weekly
weight gain was not significantly affected (P > 0.05) by
the dietary treatments and the level of inclusion of rice
milling waste. The interaction effect was also not
significant as revealed by the profile plots of the marginal
means (Figure 2). The average weekly weight gain per
diet (g) over the eight weeks are 133.25, 130. 75, 130.00,
and 130.50 (Tables 4) for D1, D2, D3, and D4,
respectively. The pattern for the weight gain per diet
revealed that D1 > D2 > D4 > D3. Generally, the animals
in this study irrespective of the dietary treatment and the
level of inclusion of the rice milling waste did not record
significant (P > 0.05) difference in the average weekly
weight gain. There were however, significant effects of
initial weight on performance of animals during the first 2
weeks with the heavier animals having a higher rate of
gain. Similar findings were reported for growing rabbits
fed low protein diets supplemented with or without urea
28 Afr. J. Pure Appl. Chem.
Table 5. Performance of the weaner rabbits fed with different levels of untreated and urea treated rice milling waste based
diets.
Parameter
Diet 1
Diet 2
Diet 3
Diet 4
SEM
SL
No. of days of trial
56
56
56
56
No. of animals
4
4
4
4
Average initial live weight (g)
550.00
555.00
540.00
540.00
Average final live weight (g)
1616.00
1601.00
1580.00
1584.00
Total weight gain (g)
1066.00
1046.00
1040.00
1044.00
Average weekly weight gain (g)
133.25
130.75
130.00
130.50
3.36
NS
Average daily weight gain (g)
19.04
18.67
18·57
18.64
Total feed intake (g)
3859.03
3674.44
3474.73
3704.82
Average daily feed intake (g)
68.89
65.62
62.05
66.16
1.01
NS
FCR
3.62
3.51
3.34
3.55
0.11
NS
FCR = Feed conversion ratio; SEM = Standard error of the mean; SL = Significance Level, NS = not significant.
Table 6. ANOVA tests of between-subjects effects
Source
Type iii sum of squares
df
Mean square
F
P/Sig.
DT
108.892
1
108.892
3.367
0.077
LI
79.286
1
79.286
2.452
0.129
DT * LI
1.399
1
1.399
0.043
0.837
Error
905.472
28
32.338
Dependent Variable: Feed Intake, (α = 0.05); DT = Dietary treatment; LI = Level of inclusion; df = Degrees of
freedom.
Figure 1. Profile plots of marginal means of feed intake. N = Untreated diets, T = Treated diets,
VAR00001 = Dietary treatment, VAR00002 = Level of inclusion, VAR00003 = Dependent variable
(Feed Intake).
or methionine (Raharjo, 1986).
The FCR obtained (Table 5) showed the same trend as
the average daily feed intake: D1 > D4 > D2 > D3. The
FCR of 3.67, 3.59, 3.39, and 3.62 for the rabbits on D1,
D2, D3, and D4, respectively did not show significant (P >
0.05) (Table 8) interaction within the dietary treatments
Ubwa et al. 29
Table 7. ANOVA tests of between-subjects effects.
Source
Type III sum square
df
Mean square
F
P/Sig
DT
18.000
1
18.000
0.050
0.825
LI
24.500
1
24.500
0.068
0.797
DT * L
I 8.000
1
8.000
0.022
0.883
Error
10135.000
28
361.964
Dependent variable: Weight Gain, (α = 0.05); TM = Dietary treatment, LI = Level of inclusion, df =
Degrees of freedom.
Figure 2. Profile plots of marginal means of weight gain. N = Untreated diets, T =
Treated diets, VAR00001 = Dietary treatment, VAR00002 = Level of inclusion,
VAR00003 = Dependent variable (Weight Gain).
Table 8. ANOVA tests of between-subjects effects.
Source
Type III sum of squares
df
Mean square
F
P/Sig.
DT
0.194
1
0.194
0.550
0.465
LI
0.137
1
0.137
0.387
0.539
DT * LI
0.047
1
0.047
0.134
0.717
Error
9.861
28
0.352
Dependent Variable: Feed Conversion Ratio, (α = 0.05); TM = Dietary treatment, LI = Level of inclusion, df =
Degrees of freedom.
and level of inclusion. The non significant level of
interaction is demonstrated in the profile plots of the
marginal means (Figure 3). This indicates similar
utilization of nutrients by the experimental rabbits. The
similar performance of rabbits observed in this study may
be due to the similar proximate composition of the
experimental diets.
The results of the nutrient digestibility of the rabbits are
presented in Table 9. The feed dry matter, crude protein,
crude fibre, and ash showed similar digestibility within the
dietary treatments and the different levels of inclusion.
The digestibility ranged from 77.25 to 78.55% for dry
matter, 67.51 to 69.45% for crude protein, 49.80 to
50.45% for crude fibre, and 63.89 to 65.35% for ash. The
similar nutrient digestibility recorded among the different
group of the rabbits may be attributed to the similarity in
the chemical composition of the diets. Report has shown
that feed which vary relatively little in composition will
show little variation in digestibility (McDonald et al., 1987
a, b). The values obtained in the present study are
30 Afr. J. Pure Appl. Chem.
Figure 3. Profile plots of marginal means of feed conversion ratio. N = Untreated
diets, T = Treated diets, VAR00002 = Dietary treatment, VAR00003 = Level of
inclusion, VAR00004 = Dependent variable (Feed conversion ratio).
Table 9. Nutrient digestibility by rabbits fed different levels of untreated and urea
treated rice milling waste based diets.
Parameter (%)
D1
D2
D3
D4
Dry matter
78.55
78.07
77.40
77.25
Crude protein
69.45
68.27
67.51
68.01
Crude fibre
50.03
51.15
49.80
50.45
Ash
65.35
64.27
63.89
64.02
comparable with those earlier reported for weaner rabbits
fed with similar diets (Abonyi et al., 2012).
Conclusion
The result of this study indicated that the chemical
composition of rice milling waste can be highly varied
when treated with urea which resulted in modification of
the chemical composition of the waste. The modification
however, did not significantly affect the growth
performance and nutrient digestibility of the experimental
rabbits in this work. Thus, weaner rabbits can be
successfully raised on a commercial chick mash diet
blended with 35% rice milling waste with good initial
quality treated or untreated without any adverse effect on
growth performance and nutrient digestibility.
ACKNOWLEDGEMENT
The authors would like to thank the management of
Federal College of Education (Technical) Asaba, for
allowing the use of their metabolic cage for rearing the
rabbits.
REFERENCES
Abonyi FO, Iyi EO, Machebe NS (2012). Effects of feeding sweet potato
(Ipomoea batatas) leaves on growth performance and nutrient
digestibility of rabbits. Afr. J. Biotechnol. 11(15):3709-3712.
Adeniji AA (2010). Effects of dietary grit inclusion on the utilization of
rice rusk by pullet chicks. Trop. Subtrop. Agroecosyst. 12:175-180.
Aduku AO (2004). Animal nutrition in the tropics: feeds and feeding,
pasture management, monogastric and ruminant nutrition. Zaria,
Nigeria, pp. 31-43.
Amaefule KU, Iheukwumere FC, Lawal AS, Ezekwonna AA (2006). The
effect of treated rice milling waste on performance, nutrient retention,
carcass and organ characteristics of finisher broilers. Int. J. Poult.
Sci. 5(1):51-55.
Amaefule KU, Nwogu RK, Ohazuluike N (2003). Influence of treatment
of rice mill waste on its nutritional value for broilers. J. Sustain. Agric.
Environ. 5:196-203.
Ambasankar K, Chandrasekan D (2002). Feeding value of rice waste
for layers and its effect on egg quality. Indian Vet. J. 79:39-42.
Ambaye TD (2009). On-farm evaluation of urea treated rice straw and
rice bran supplementation on feed intake, milk yield and composition
of fogera cows, North Western Ethiopia. MSc. Thesis, Bahir Dar
University, Bahir Dar, pp.6-10.
Amdt DC, Richardson CR, Sheirol LB (1980). Digestibility of chemically
treated cotton plant by-product and effect on mineral balance, urine
volume, and pH. J. Anim. Sci. 51(1):215-218.
AOAC (1980). Association of Official Analytical Chemists, Official
methods of analysis. 15th ed., Washington DC.
Beagle EC (1978). Rice husk conversion to energy.FAO Consultant.
Rome, Italy.
Belewu MA, Babalola FT (2009). Nutrient enrichment of waste
agricultural residues after solid state fermentation using
Rhizopusoligosporus. J. Appl. Biosci. 13:695-699.
Bhattacharya SC, Joe MA, Kandhekar ZP, Salam A, Shrestha RM
(1999). Greenhouse-gas emission mitigation from the use of
agricultural residues: the case of rice husk. Energy 24:43-59.
Chenost M (1995). Optimizing the use of poor quality roughage through
treatments and supplementation in warm climate countries with
particular emphasis on urea treatment.First Electronic Conference on
Tropical Feeds FAO, Rome.
Crampton EW, Harris LE (1969). Applied animal nutrition.
In:Ambasankar, K.and Chandrasekan, D (2002). Feeding value of
rice waste for layers and its effect on egg quality. Indian Vet. J.
79:39-42.
Farell DJ (1994). Utilization of rice bran in diets for domestic and
ducklings. Worlds Poult. Sci. J. 50:115-132.
Maikano A (2007). Utilization of rice offal in practical ration of broilers.
Zoologist 5:1-7.
McDonald P, Edwards RA, Greenhalgh JFD (1987a). Animal nutrition
Longman Group (FE) Ltd 4thed., pp. 24-25.
McDonald P, Edwards RA, Greenhalgh JFD (1987b). Animal nutrition
Longman Group (FE) Ltd 4thed., pp. 24-25.
NAERLS and PCU (2004). Field situation assessment of 2004. In:
Maikano A (2007). Utilization of rice offal in practical ration of broilers.
The Zoologist. 5:1-7.
Oluokun JA (2005). Intake, digestion and nitrogen balance of diets
blended with urea treated and untreated cowpea husk by growing
rabbit. Afr. J. Biotechnol. 4(10):1203-1208.
Ubwa et al. 31
Preston TR, Leng RA (1987). Matching ruminant production system with
available resources in tropics and sub-tropics; Australia, Penambul
Books, Armidale, Australia. P. 259.
Raharjo YO, Cheeke PR, Patton NM (1986). Growth and reproductive
performance of rabbits on a moderately low crude protein diet with or
without methionine or urea supplementation. J. Anim. Sci. 63:795-
803.
Rexen F, Vestergaard KT (1976).The effect of digestibility of a new
technique for alkali treatment of straw. Anim. Feed Technol. 1:73-83.
Saunders RM (1990). The properties of rice bran as a food stuff. Cereal
Foods World 35:632-639.
Singh KS, Marwaha VK (1968). In Ambasankar, K. and Chandrasekan,
D. (2002).Feeding value of rice waste for layers and its effect on egg
quality. Indian Vet. J. 79:39-42.
Sundstol F, Coxworth EM (1984). Ammonia treatment. In: Sundstol,F.
And Owen, E.(Eds). Straw and other fibrous by-products as feed.
Elsevier, Amesterdam., pp. 196-247.
Taiwo AA, Adebowale EEA, Greenhalgh JFD, Akinsoyinu AO (1992).
Effects of urea treatment on the chemical composition and
degradation characteristics of some crop residues. Nig. J. Anim.
Prod. 19:25-34.
Thipwimon C, Shabbir HG, Suthum P (2004).Environmental profile of
power generation from rice husk in Thailand. The Joint International
Conference on“Sustainable Energy and Environment (SEE)”.
Yakubu B, Adegbola TA, Bogoro S, Yusuf HB (2007). Effect of urea
treated and untreated rice offal on the performance of broilers: growth
performance and economy of production. J. Sustain. Develop. Agric.
Environ. 3:7-13.
