Malnutrition is a great problem facing people in the developing countries
due to inability to afford proteins from animal sources which are highly
nutritious. Hence, majority of these people depend on proteins of plant
origins because they are cheap and more accessible. This implies that
only a small proportion of the food consumed in these countries is derived
from livestock products (Abalu, 1982). This nutrition problem has led
to failing health, children malnutrition and high rate of mortality in
developing countries especially in Africa. Hence, to alleviate malnutrition
and its attendant problems, efforts are been diverted to production of
livestock that can meet the rising demand of animal protein such as swine,
poultry, rabbits and fish as against cattle, sheep and goat which are
less prolific and have longer generation interval.
The rabbit is a small sized monogastric herbivorous animal with a short
gestation period of 28-30 days. Rabbits are prolific and can have a litter
size of up to 14 rabbits. Rabbits are easy to manage and they can turn
80% of forage consumed into edible meat. Rabbits produce nutritionally
excellent meat that is easily digested, high in protein and minerals and
low in fat, steric and oleic acids than the meat of some other animals.
Rabbit has a dressing percentage of 48.1% which is higher than that of
As feed represents the major cost in any livestock production, cost of
feeding is the major challenge facing rabbit production. Atteh (2002)
reported that the price of maize increased from 15 Naira (N) per kg in
January to N40 in June of year 2000. Maize accounts for about 45% of the
diet of rabbits, hence such price changes will induce a classic increase
in the price of finished feed. There is therefore the need to research
into the use of cheap and unconventional feed ingredients for compounding
rabbit diets so as to boost rabbit production.
Bovine rumen content which is the content of the first stomach compartment
of slaughtered cattle is a material that has been utilized as feedstuff
in poultry, swine and ruminant diets. Rumen Content (RC) is made up of
undigested feed eaten by the ruminant animal, lots of micro-organisms
that aid in feed degradation, the feed and synthesized protein, fatty
acids and vitamins produced by the microbes. RC is highly fibrous; hence
supplements that can aid digestion of fibre such as enzyme may be needed
when using RC in feed formulation especially for monogastrics feed.
The enzyme used in this research work is Allzyme which is a naturally
occurring enzyme complex produced by a fungus called Aspergillus niger,
using the process of solid state fermentation. Allzyme consists of 7 active
enzymes which are amylase, betaglucanase, protease, cellulose, pectinase,
phytase and xylanase.
This study was aimed at determining the amount of maize that can be replaced
by DRC in the diet of weaner rabbits in order to reduce the cost of rabbit
feed which will consequently lead to a boost in rabbit meat production
and consumers accessibility to cheaper meat. The aim is to reduce the
use of maize (which is expensive) in rabbit feed.
MATERIALS AND METHODS
A total of 48 weaner rabbits were used in this trial that lasted for
8 weeks. The experiment was carried out in year 2006 at University of
Ilorin, Ilorin, Nigeria. The rabbits were randomly allocated to four dietary
treatments. Each treatment had 3 replicates of 4 rabbits per replicate.
The 4 dietary treatments had DRC replacing maize at 0, 33.33, 66.67 and
100% levels (Table 1). All the dietary treatments except 0% DRC were supplemented
with allzyme (Recommended inclusion is 200 g t-1 of feed).
The rumen content was collected at the abattoir at slaughter time, immediately
the rumen was split open. The RC was left in a container to decompose
for five days. On the fifth day, the RC was boiled cin a drum for 2 ½
h with constant stirring. The boiled RC was then spread to dry until the
moisture content was below 10% after which it was milled. The DRC fed
was analysed to contain 9% crude protein, 16.20% crude fibre, 4.25% ether
extract, 16% ash and 95.86% dry matter.
||Composition of experimental diets (kg/100kg)
|*: Biomix-Vit. Premix used contained Vit. A: 330,000IU;
Vit D3: 330,000IU; Vit E: 16,500IU, Vit A3:
506 mg: Riboflavin: 3.3 g; Pantothenic acid: 9.9 g; Niacin: 11 g;
Vit B12: 20 mg; Chlorine: 220 g, Zinc: 207 g; Fe: 20.7
g; Copper: 2.07 g; Mg: 4.17 g; I: 62 mg; Se: 62 mg
The rabbits were allowed 1 week adaptation period to adjust to the feeds
and cage prior to the 8 weeks data collection. At the commencement of
the experiment, the rabbits were dewormed with ivomec and embazin fort
(Coccidiostat) was also administered to them. Feed and water were supplied
ad libitum throughout the experimental period. At the last week
of the experiment, the rabbits were placed in metabolic cages for digestibility
trial which lasted for 72 h. The total collection method was adopted.
Faeces were collected, dried, measured and stored, while the urine collected
was stored in plastic bottles and Tetraoxosulphate (6) acid (H2SO4)
added as preservative.
Proximate analysis was conducted using the methods of AOAC (1980). Records
of initial and weekly live-weight and daily feed intake were kept and
feed to gain ratio calculated. All data were subjected to analysis of
variance using the completely randomized design and significant differences
in treatment means were compared using Duncan`s multiple range test (Duncan,
RESULTS AND DISCUSSION
The growth performance characteristics of weaner rabbits fed diets in
which DRC replaced maize is shown in Table 2. No significant effect (p>0.05)
of treatment was observed on feed intake by the rabbits fed on 0, 33.33
and 66.67% DRM diets with values of 96.83, 95.44 and 96.43 g, respectively.
100% DRM diet however, had a significant effect (p<0.05) on feed intake
with a value of 84.48g. There was no significant difference in the weight
gain values obtained for 0%, 33.33% and 66.67% DRC replacement for maize
diets (DRM), although the weight gain of rabbits tended (p>0.05) to
decrease with increasing level of DRC. However, 100% DRM diet showed a
significant effect (p<0.05) on weight gain. Feed to gain ratio obtained
in rabbits fed 0, 33.33 and 66.67% DRM diets were highly comparable (p>0.05).
At 100% replacement level of DRC, feed to gain ratio showed a significant
decrease (p<0.05) with a value of 8.16 compared to 7.44, 7.42 and 7.68
for rabbits fed 0, 33.33 and 66.67% DRM diets, respectively.
Feed cost decreased with increase in the level of DRC in the weaner diets
from N33.50 at 0% to N 17.14 at 100% replacement level. However, profitability
of the dietary treatments decreased with increasing DRC in the diets.
The result of the nutrients digestibility trial for weaner rabbits fed
DRC replacement for maize diets (DRM) is shown in Table 3. There was significant
effect of treatments on nitrogen and crude fibre digestibility obtained,
while treatment effect on crude oil fat digestibility is insignificant
(p>0.05). Both nitrogen and crude fibre utilization decrease with increasing
DRC in the diets, while crude fat digestibility tended to increase with
increasing DRC level. Crude protein digestibility value obtained in rabbits
fed 100% DRM diets is significantly (p<0.05) lower than that of the
other diets while 0% DRM diet gave a significantly higher (p<0.05)
protein digestibility value than other diets. However, the digestibility
values obtained at 33.33 and 66.67% DRM diets were highly comparable (p>0.05)
(70.35 vs. 70.30).
||The effect of replacing maize with drc on the growth
performance and cost benefit of rabbits
|Means in the same column not followed by the same superscript
letter(s) are significantly different (p<0.05), *: N 130 = $ 1
as at the time the experiment was conducted in 2006
||Effect of DRC replacement for maize on nutrient digestibility
|Means in the same column not followed by the same superscript
letter(s) are significantly different (p<0.05)
The different dietary treatments had significant effect (p<0.05) on crude
fibre digestibility of the fed rabbits, hence fibre utilization of the rabbits
fed different diets were not comparable. In crude fat digestibility, the
values obtained at different levels of DRM are comparable (p>0.05), 100%
DRM diet however, gave the highest value of 81.18. There was no mortality
throughout the experimental period.
The significantly different feed intake, weight gain and feed to gain
ratio observed at 100% DRC replacement for maize (DRM) diet as compared
to the other test diets may be attributed to the higher fibre content
of 100% DRM diet. According to Scott et al. (1969), the amount
and constitution of crude fibre in the diet; as well as the type and stage
of development of the animal have marked effects on monogastric nutrition.
Kass and Pond (1980) also stated that high fibrous feeds have depressing
effect on body weight gain and feed to gain ratio in non ruminants. However,
the highly reduced feed intake of rabbits on 100% DRM (45% DRC) observed,
is in contrast to the report of Lindderman (1986) that pigs fed peanut
hills consumed 24 to 71% more feed than the control pigs. This difference
in feed consumption of the pigs and rabbits may be due to the type and
stage of development of each of the monogastrics as explained by Scott
et al. (1969).
The observed reduction in feed intake is however supported by Onwudike
(1986), who reported that the grittiness of PKC as a result of its highly
fibrous nature was responsible for reduced feed intake of starter and
The insignificant effect of DRC on weight gain, feed intake and feed
to gain ratio obtained at 0, 33.33 and 66.67% is similar to the report
of Aduku et al. (1988). This could be due to the fact that rabbits
as non-ruminant herbivores can tolerate considerable levels of fibre in
their diets. Aduku et al. (1988) suggested that high crude fibre
level of PKC did not have effect on growth parameters off rabbits because
of coprophagy which allows further digestion of the fibre. Barnes et
al. (1963) was also in support that coprophagy contributes 12-25%
of the growth in rabbits. Harris et al. (1983) also observed insignificantly
different weight gains for rabbits fed high and low crude fibre.
Increasing the replacement level of DRC for maize resulted in decreasing
cost of feed because DRC is a cheap abattoir waste that can be collected
freely and the only costs incurred are in transportation and processing
of the rumen content. Hence, DRC is a good substitute for maize in reducing
feed cost of rabbits especially during periods of maize scarcity or when
maize is highly expensive. Although 33.33% DRM diet had a higher feed
cost than the other diets containing DRC, it gave the highest profitability
estimate among the DRM diets.
The significantly decreasing crude protein and crude fibre digestibility
as DRC level increased in the diets may be attributed to poor utilization
of the nutrients as a result of increasing fibre content of the diets.
This is in agreement with the report of Babatunde et al. (1975)
that linked the low digestibility values for PKC to its fibre content.
Proximate analysis of the test diets (Table 1) showed increasing crude
fat content with increasing DRC level. This may explain the insignificantly
increasing crude fat digestibility observed.
The results obtained in this experiment showed that DRC has a high feedstuff
potential in rabbit nutrition. The result also showed that growth performance
characteristics of the test rabbit were not adversely affected as a result
of replacing DRC for maize in their diets. For economic rabbit production,
66.67% of enzyme supplemented DRC replacement for maize is being recommended
for weaner rabbit diet.