Livestock Research for Rural Development 19 (4) 2007 | Guide for preparation of papers | LRRD News | Citation of this paper |
Thirty rabbits of mixed sexes with an average initial weight of 600g were used to evaluate the effect of replacing maize with sun dried cassava waste meal on growth performance and carcass characteristics of rabbits. Five experimental isonitrogenous (18%cp) diets were formulated such that sun dried cassava waste replace maize at 0%, 25%, 75% and 100%. The rabbits were randomly allocated to these 5 isonitrogenous diets. Each dietary treatment consists of 2 replicates with 3 rabbits in each replicate. Water and feed were provided ad-libitum throughout the experimental period of 91 days.
The result shows that dietary treatment did not have effect on feed in take, average daily weight gain, feed efficiency and carcass characteristics. The cost of producing a unit weight of rabbit was greatly reduced by replacing maize with cassava waste meal. Cassava waste meal may therefore be used instead of maize in rabbit diets to reduce cost of feed and the heavy dependence on maize in animal feeding.
Key words: carcass characteristics, cassava waste, growth performance, rabbit
There has been for quite sometimes a continuous call for the improvement of the nutritional status of the citizens of many third world countries like Nigeria through substantial increase in the intake of protein of animal origin (Owen 1976)
In Nigeria and other developing countries, there is animal protein malnutrition. An average Nigeria takes about 5.5g of animal protein per day which is quite very low when compared to the recommendation of food and Agricultural organization (FAO 1990) in which a minimum animal protein intake of 30g per person per day is recommended for an adult. The problem of low intake of animal protein is due to poor economics situation as well as high cost of feeds in intensive commercial units.
Rabbit industry is now growing in many African countries. The
population of rabbit in Nigeria as at 1993 was estimated to be
1.7million (Nigeria Tribune 1993). Commercial and research units
which depend mainly on concentrate and pellet for their animals are
now being faced with the same feeding problems associated with
poultry and pig farming. The cereal grain supplies the bulk of the
livestock feed. However in the less developed countries, cereal
grains are in high demand for human uses and the production has
never been adequate to meet the need of the increasing population,
consequently, there is little or no excess grain for livestock
feed. In addition, the little maize available are very expensive.
For instance, in the year 2005, the price of maize rose from about
#30 to #70 per kilogramme. This continuous increase in the cost of
conventional ingredients used in compounding livestock feed has
necessitated intensive investigation into cheap alternative source
of energy yielding unconventional ingredients. This research work
therefore aimed at investigation the effect of replacing maize with
sun-dried cassava waste meal in the diet of rabbits on their growth
performance and carcass characteristics. It also aimed at
determining the cost-benefit of replacing maize with cassava waste
meal in the diet of rabbits.
Cassava peel of mixed varieties were collected within 24 hours after peeing the tuber from a gari- processing industry at Taiwo road, Ilorin Kwara State, Nigeria, then sun dried for 5 days under intensive sunshine and grounded in an hammer mill. The feed ingredients used were purchased at ROFAT feed mill in Ilorin.
Thirty (30) rabbits of mixed sexes with an average weight of 0.6kg were used for this experiment. The animals were randomly allocated into 5 dietary treatments with 2 replicates and 3 animals per replicate. All the diets (Table 1) were made isonitrogenous (18% crude protein).
Table 1. Percentage composition of the diets |
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Ingredients |
0% Replacement Diet 1 |
25% Replacement Diet 2 |
50% Replacement Diet 3 |
75% Replacement Diet 4 |
100% Replacement Diet 5 |
Maize |
32.00 |
24.00 |
16.00 |
8.00 |
0.00 |
Cassava waste meal |
0.00 |
8.00 |
16.00 |
24.00 |
32.00 |
Wheat offal |
6.00 |
6.00 |
6.00 |
6.00 |
6.00 |
Corn brain |
27.50 |
27.00 |
27.00 |
26.00 |
25.50 |
Soya bean meal |
9.00 |
9.00 |
9.00 |
10.00 |
11.00 |
Palm kernel cake |
16.50 |
16.50 |
16.00 |
16.00 |
16.00 |
Blood meal |
5.00 |
5.60 |
6.00 |
6.00 |
6.00 |
Bone meal |
3.50 |
3.50 |
3.50 |
3.50 |
3.50 |
Vitamin premix |
0.25 |
0.25 |
0.25 |
0.25 |
0.25 |
Salt |
0.25 |
0.25 |
0.25 |
0.25 |
0.25 |
Total |
100.0 |
100.00 |
100.00 |
100.00 |
100.00 |
Moisture content |
9.40 |
7.90 |
8.20 |
8.50 |
8.30 |
Crude protein |
18.16 |
18.48 |
18.38 |
18.48 |
18.38 |
Crude fibre |
6.83 |
8.24 |
9.67 |
11.10 |
12.53 |
Crude fat |
3.50 |
6.00 |
6.00 |
3.50 |
4.50 |
Ash |
9.50 |
8.00 |
8.00 |
9.50 |
9.00 |
Nitrogen free extract |
56.69 |
59.28 |
57.95 |
52.42 |
55.59 |
The initial weights of the animal were taken before introducing them to the experimental diets. They were supplied water and feed ad-libitum twice daily for a period of 13 weeks. Drugs were administered to prevent coccidiosis. The records of feed offered and left over were kept daily to estimate daily feed consumption. At the end of the feeding trial, four (4) rabbits were randomly selected from each treatment (i.e 2 rabbits per replicate) for carcass evaluation. These were weighed, fasted overnight and re-weighed prior to slaughtering. The animals were thoroughly bled by hanging them head down through the hind leg on a nail, then the carcass were dissected and eviscerated. The weight of internal and external offal were taken and recorded. The carcass were chilled in a freezer for twenty-four hours and re-weighed (after thawing) to determine the cold carcass weight and then dissembled into wholesale cut and each primal part was weight. Percentage lean content (determined by the ratio of lean meat to the total carcass), water holding capacity of the meat (determined by spinning 5g of chopped meat in a centrifuge, the water on top of the meat was decanted and the remaining meat sample was weight, then ratio of weight of water to the original sample was multiplied by 100) and the fat content of the meat (extracted using solicit extractor) were determined.
To calculate the cost per kg feed, the price of each ingredient was taking and this was used to multiply the quantity (kg) of ingredients used in compounding each diet. Then summed up for different experimental diets for the calculation of feed cost per kg weight gain.
Data collected on the various parameters were analysed using
the complete Randomized Design (CRD) (Steel and Torries 1980).
Differences between treatment means were examination by Duncan
multiple Range test (Duncan 1955).
The results of growth performance and cost analysis are presented in table 2.
Table 2. Mean values for growth performance and cost analysis of rabbits as influenced by the dietary inclusion of cassava peel meal |
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Parameters |
Diet 1 0% Replacement |
Diet 2 25% Replacement |
Diet 3 50% Replacement |
Diet 4 75% Replacement |
Diet 5 100% Replacement |
SEM |
Significance |
Initial weight, g |
576 |
481 |
490 |
460 |
505 |
46.84 |
NS |
Final weight, g |
1503 |
1193 |
1093 |
1307 |
1527 |
108.76 |
NS |
Daily weight gain, g |
10.22 |
7.80 |
6.55 |
9.34 |
11.27 |
1.04 |
NS |
Daily feed intake, g |
44.47 |
45.15 |
39.83 |
46.15 |
49.03 |
2.79 |
NS |
Feed conversion ratio |
4.36 |
5.20 |
6.23 |
4.98 |
4.36 |
0.72 |
NS |
Cost/kg feed # |
16.33 |
15.13 |
13.95 |
13.08 |
12.22 |
– |
– |
Feed cost/kg weight (#) |
71.11 |
78.60 |
86.84 |
65.07 |
53.22 |
– |
– |
*NS – Not significant (p>0.05) |
There was no significant difference (p> 0.05) in the initial average weight, final average weight, average daily weight gain, average feed intake and feed conversion ratio for rabbits on the five diets, although rabbits on 100% replacement diet recorded highest daily feed intake and daily weight gain. The high feed intake value observed in rabbit fed diet 5 (100% maize replaced with sun- dried cassava peel meal) could be attributed to favourably high crude fibre content of cassava peels. According to Lebas (1983) an increase crude fibre will result in increase voluntary feed intake for growing rabbits. This result was similar to the observation of Agunbiade et al (1999) when they included cassava peel and leaves in the diet for growing rabbits.
The cost per kilogramme of feed was reduced generally with increased dietary cassava waste meal. Diet 5 (100% maize replacement diet) also showed the best cost per kg weight gain and this tends to increase as the inclusions level of cassava peel meal declines (Table 2)
The replacement of maize with cassava waste meal in rabbit diet did not have significant influence (p>0.05) on live shrunk weight, dressed carcass weight, carcass length, percentage muscle and bone ratio as shown in table 3.
Table 3. Slaughter characteristics of rabbits as influenced by the dietary inclusion of cassava peel meal |
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Parameters |
Diet 1 0% Replacement |
Diet 2 25% Replacement |
Diet 3 50% Replacement |
Diet 4 75% Replacement |
Diet 5 100% Replacement |
SEM |
Significance |
Liveweight at slaughter, g |
1450 |
1225 |
1210 |
1231 |
1495 |
130 |
NS |
Dressed carcass weight, g |
692 |
595 |
582 |
627 |
737 |
74 |
NS |
Dressing Percentage, g |
49.2 |
48.1 |
47.8 |
49.6 |
49.2 |
1.62 |
NS |
Carcass length, cm |
24.2 |
22.5 |
22.2 |
23.4 |
23.4 |
0.90 |
NS |
Percentage Muscle, % |
86.4 |
85.4 |
88.9 |
83.4 |
88.7 |
2.41 |
NS |
Percentage bone, % |
13.6 |
14.5 |
11.0 |
16.5 |
11.3 |
2.41 |
NS |
*NS- Not significant (p>0.05) |
Dressing percentage reported in this study are comparable to the observation of Agunbiade et al (1999) for rabbits fed varying levels of cassava peel and cassava leaves meal diet but Ogunboyede (1991) reported that cassava peel could comprise of about 40% of the diet of growing rabbits as suggested earlier by Omole and Sonaiya, (1981) who reported that growing rabbits efficiently utilized a ration containing 40% cassava peel.
Effect of replacing maize with varying levels of sun dried cassava waste meal on rabbits carcass primal cuts is shown in table 4.
Table 4. Primal cuts of rabbit as influenced by the dietary inclusion of cassava peel meal |
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Parameters, % |
Diet 1 0% Replacement |
Diet 2 25% Replacement |
Diet 3 50% Replacement |
Diet 4 75% Replacement |
Diet 5 100% Replacement |
Significance |
Right side shoulder |
14.24 |
13.21 |
12.95 |
12.14 |
12.59 |
NS |
Right side rib |
6.23 |
6.71 |
6.72 |
5.90 |
6.83 |
NS |
Right side Loin |
10.18 |
9.14 |
11.90 |
10.54 |
12.19 |
NS |
Right side leg |
19.24 |
20.15 |
20.74 |
19.65 |
20.48 |
NS |
Shoulder muscle |
12.73 |
11.25 |
10.94 |
10.46 |
10.49 |
NS |
Rib Muscle |
5.28 |
5.71 |
5.72 |
5.05 |
5.58 |
NS |
Loin Muscle |
8.84 |
8.12 |
10.02 |
9.27 |
10.74 |
NS |
Leg Muscle |
16.47 |
17.69 |
17.85 |
17.16 |
17.45 |
NS |
Shoulder bone |
1.51 |
1.97 |
2.01 |
1.86 |
1.77 |
NS |
Rib bone |
0.95 |
1.00 |
1.00 |
0.85 |
1.26 |
NS |
Lion bone |
1.35 |
1.02 |
1.88 |
1.27 |
1.45 |
NS |
Leg bone |
2.77 |
2.56 |
2.84 |
2.49 |
3.05 |
NS |
NS – Not significant (p>0.05) |
It was observed that the replacement of maize with cassava waste meal in rabbit rations had no significant effect (p>0.05) on the weight of carcass primal parts. Higher values in primal cuts were observed in the animal fed with diet 5 than those fed with control diet.
The influence of replacing maize with cassava peel meal in rabbit diet on the internal and external offal of rabbit was as presented in table 5.
Table 5. Internal and external offal of rabbits as influenced by the dietary inclusion of cassava peel meal |
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Parameters |
Diet 1 0% Replacement |
Diet 2 25% Replacement |
Diet 3 50% Replacement |
Diet 4 75% Replacement |
Diet 5 100% Replacement |
SEM |
Significance |
External offals, % |
|
|
|
|
|
|
|
Head |
10.17 |
10.62 |
11.26 |
10.41 |
9.86 |
0.41 |
NS |
Pelt |
7.98 |
8.65 |
7.87 |
7.98 |
8.81 |
0.65 |
NS |
Tail |
0.50 |
0.60 |
0.56 |
0.43 |
0.56 |
0.07 |
NS |
Fore feet |
0.64 |
0.70 |
0.72 |
0.58 |
0.63 |
0.08 |
NS |
Hind feet |
1.65 |
2.01 |
1.92 |
1.86 |
1.72 |
0.13 |
NS |
Internal offals, % |
|
|
|
|
|
|
|
GIT |
41.25 |
42.60 |
44.75 |
39.85 |
46.45 |
5.39 |
NS |
Liver |
5.71 |
5.08 |
4.98 |
4.99 |
5.49 |
0.55 |
NS |
Kidney |
1.39 |
1.26 |
1.13 |
0.91 |
1.18 |
0.16 |
NS |
Lung with trachea |
0.89 |
1.32 |
1.07 |
1.10 |
1.44 |
0.18 |
NS |
Heart |
0.45 |
0.46 |
0.50 |
0.33 |
0.45 |
0.06 |
NS |
NS – Not significant (p>0.05) |
The carcass internal and external offal were not significantly affected (p>0.05) by the dietary replacement of maize with cassava peel meal. The result obtained for the external offal in this study were in close range with the result obtained by Olorunsanya et al (1999) for rabbits fed diet with varying levels of pueriaria seed meal.
The result of chemical characteristics of rabbit meat as influenced by the diets is shown in Table 6.
Table 6. Chemical properties of rabbit meat as influenced by the dietary inclusion of cassava peel meal |
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Parameters |
Diet 1 0% Replacement |
Diet 2 25% Replacement |
Diet 3 50% Replacement |
Diet 4 75% Replacement |
Diet 5 100% Replacement |
SEM |
Significance |
Moisture content of the Loin Muscle, % |
74.84 |
76.41 |
75.83 |
77.34 |
76.04 |
2.54 |
NS |
Crude fat of the Loin Muscle, % |
17.14 |
15.06 |
17.56 |
12.14 |
14.30 |
5.09 |
NS |
Water Holding Capacity of the Loin muscle, % |
5.35a |
14.95b |
6.57a |
8.69a |
16.15b |
2.35 |
* |
*Mean value within row carrying different superscript differ significant (p<0.05) |
The water holding capacity of the meat was significantly improved (p<0.05) by the diets. Rabbits fed diet 2 and 5 (25 and 100% maize replaced with cassava peel meal respectively) had significantly (p<0.05) higher water holding capacity compared with the control diet.
The moisture contents of the rabbit meat is not significantly
different (p>0.05) among the treatment groups and the value
obtained in this study is slightly higher than that reported by
Fisher et al (1985). Also there was no significant different
(p>0.05) in the crude fat of the loin muscle of rabbits across
the treatment.
The result of this study indicates that the cassava waste meal,
which is economically cheaper than maize can be used successfully
to replace maize in conventional rabbit feed without any depression
or adverse effect on the growth performance and carcass
characteristics.
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Received 18 July 2006; Accepted 25 February 2007; Published 2 April 2007