Nutrient Intake, Digestion, and Utilization by Rabbits Fed Cowpea Hull and Soybean Hull-Based Diets
Chapter One
Objective of the study
The study aims at determining the nutrient intake, digestibility and utilization by rabbits fed cowpea hull and Soybean hull based diet.
The specific objectives of the study are as follows:
- To determine the dietary levels of cowpea hull and soybean hull on growth performance of rabbits.
- To determine the optimum levels of inclusion of cowpea and soybean hulls in the diets of growing rabbits.
- To determine the effects of graded levels of cowpea hull and soybean hull on haematology and organ characteristic of rabbits.
- To determine the cost implication of feeding graded levels of cowpea hull and soybean hull to rabbits
- To determine the gross pathological effects on and mortality of rabbits fed graded levels of cowpea hull and soybean hull.
CHAPTER TWO
Rabbit: An Overview
There is no concise account on the history of domestication of rabbit as various dates have suggested. Cheeke et al., (1982) stated that rabbits were domesticated in Spanish Peninsula or southern France as early as 1000AD. Zeuner (1963) gave an interesting account of the origin of rabbits from antiquity to the second half of 20th century when he stated that rabbit originated in the Iberian Peninsula and has been kept in captivity by man since Roman times and were not truly domesticated until the first century BC.
The domestic rabbit descended from the wild European rabbit (Oryctolagus Cuniculus) of the order Lagomorpha and family Leporidae.
The Attributes of rabbit in small farming system.
- Rabbit is a small docile herbivorous animal that stands midway between ruminant and non-ruminant (Lebas et al.1986), with characteristic features such as a small body size weighing between 1kg for small breeds and 9kg for some breeds like Flemish giant in temperate countries (Odubote, 1988). There are a number of advantages of the small body size e.g., it requires small amount of feed and use inexpensive, easily constructed housing. The small body size provides a small carcass that can be consumed by a family in one meal, eliminating the need for meat storage and refrigeration. The meat is stored on the live animal until needed. Rabbits are biological refrigerators (Cheeke, 1986; Lebas et al., 1986).
- Short generation time and high reproductive potential. The reproduction capacity of rabbits is legendary! Rabbits are induced ovulators, and will breed within 24h of parturition (Dickerson, 1978). Thus it is theoretically possible to produce over 11 litters per year (Cheeke, 1986). This intensive type of production could not be obtained in developing countries but it is quite feasible to produce three to five litters per year, or about 20 offspring per doe per year with only three does and a buck (Cheeke, 1986). The potential for year-round production is another advantage of rabbit.
- Utilization of Non-competitive feeds. Like ruminants rabbits can be successfully raised on grain-free diets, based on forages and by-products (Owen et al., 1977). Acceptable performance can be obtained using greens such as weeds, trees, leaves tropical legume and grass forages, vegetable tops, waste fruits and vegetables with supplement of table scraps and by-products such as rice bran and corn bran (Adam, 1976).
- Rapid growth. In American and European rabbit production, market weight fryers (2kg) is reached in 8 to10 weeks of age while the growth rate is usually lower in developing countries. Rabbits reach market or consumable size much faster than larger livestock (Cheeke, 1986).
- Potential for genetic improvement. There is a high degree of diversity in the rabbit genetic resource pool. Mature body weight ranges from less than 1kg to over 10kg, while there is much variability in traits such as maternal ability, fecundity, resistance to heat stress, etc; thus it should be possible, by selection and use of breed diversity, to make rapid improvement in animal performance.
- Production of high quality meat and useful by-products. Rabbits’ meat is high in protein and low in fat (Holmes et al., 1984), particularly when the animals are raised on a high forage low energy diet. Holmes et al. (1984) reported the fat content of cooked rabbit meat to range from 4.2 to 4.8%, Pote et al. (1980a) reported significantly higher carcass fat levels in rabbits fed high energy diets than those fed low energy diets, while Spreadbury and Davidson (1978) observed similar trends. Pote et al.(1980b) noted meat fat levels (as percentage of dry weight) to be 4.9% in rabbits fed a low energy diet of fresh forage and 14.4% in animals fed a pelleted commercial diet. The skin can be used in the production of toys, craft work and garment for such purposes (Leach and Barrett 1984). Rabbit manure is a useful fertilizer for crops and gardens. Thus rabbit production can be well-integrated into small farming systems.
Nutrient Requirements of Rabbit
The ability of the rabbit to utilize predominantly forage-based diets and so not compete with man is seen as its major attribute in developing countries with chronic protein deficiencies (Owen et al., 1977; Schlolaut, 1985).
Rabbits are simple stomached animal and are herbivorous. They have enlarged caecum more than other simple stomached animals such as swine and poultry. Rabbits kept in hutches or colonies are totally dependent on the keeper for their food. Wild rabbits pick and choose their own food. They have instinctive wisdom that helps them to select a good balanced diet, the rabbit farmer does not have this instinctive wisdom and must therefore think carefully about what is the best food for rabbit (Fielding, 1991). The nutrient requirement of rabbits cannot be over-emphasized as they are essential for rabbit’s body growth, maintenance and reproduction. A number of studies have been carried out in the temperate countries but few scientists have conducted such studies in the tropics (Omole, 1982). The nutritional requirement of rabbit for productivity like those of any other group of animals falls under the following categories: protein, energy, vitamin and mineral requirements.
Protein and Energy Requirements
The importance of protein quality in rations for rabbit is now well recognized, like other simple –stomached species, the rabbit has a reduced growth rate and food consumption when offered protein with an unbalanced amino acid protein (Adamson and Fisher, 1971 and 1973; Spreadbury, 1978). Below are the current recommendations for the requirements for essential amino acids for rabbits.
CHAPTER THREE
MATERIALS AND METHOD
Materials
The cowpea hulls used for the experiment were collected from local bean cake (popularly called “akara” in Igbo vernacular) sellers located in Okpuno-Egbu, Umudim, Nnewi North Local Government Area of Anambra State. The cowpea hulls were produced from blanched and decorticated cowpea seeds used for the production of bean cake. The hulls were sun-dried for 48hrs and passed through pental attrition mill for particle size reduction. The Soybean hulls were collected at Nkwo Nnewi Main Market, Anambra State. The hulls were produced from toasted soybean seeds which were passed through pental attrition mill for cracking and separated by blowing. Other ingredients used were obtained from different locations within Nsukka Local Government Area, Enugu State.
CHAPTER 4
RESULTS
Experiment 1
Proximate composition of experimental diets and test ingredient
Table 5 shows the proximate composition of cowpea hull used for the study while Table 6 shows the result of the proximate analysis of the experimental diets.
CHAPTER FIVE
DISCUSSION
Experiment 1
Performance of weaner Rabbits
As shown in Table 7, the control diet and the 10% CBH produced similar average final body weight that was significantly higher than that produced by 20% and 30% CPH diets. Although daily weight gain showed a linear decrease with increasing level of CPH, the daily weight gain of rabbits fed 20 and 30% CPH diets were comparable. This suggests that up to 10% CPH can be included in the diets of growing rabbits. This is because beyond 10% level, the bodyweight gain significantly decreased. Akinmutimi (2004) had observed that most processing methods employed in improving the feed value of non conventional or alternative feed stuffs do not completely eliminate anti-nutritional factor (ANF) but only reduce their concentration to tolerate levels in feed stuffs. He observed that the quantity of ANF present in formulated rations therefore will depend on the concentration (remnants) of these substances in feedstuffs which invariable is determined by processing methods. Weight gain of 8.8-11.8g obtained in this study is higher than those (2.08-6.70g) reported by Iyeghe- Erakpotobor et al (2006) with 80g bean cheese waste maize offal diet. However, it is within the range (8.53-17.22g) reported by Onyimonyi and Ene (2003) with Panicum maximum and concentrate diet.
CHAPTER SIX
SUMMARY AND CONCLUSION
SUMMARY
Animal production vis-à-vis rabbit production is seriously affected by the high cost of compounded feeds which is derived largely from the exorbitant prices and scarcity of conventional feed ingredients in Nigeria. Rabbit production remains one of the veritable ways of achieving sustainable and rapid production of high quality animal protein to meet the increasing demand of the Nigerian teeming populace. Towards attaining this goal, it is desirable to focus on nutritional strategies that will ensure greater productivity of rabbitry and offer nutritionist more flexibility to use cheap fibrous ingredients and by-products or waste in feed formulations and will variable reduce scarcity and feed cost. Cowpea hull and soybean hull are by-products from the processing of stable food e.g. akara, moi-moi, soymilk, soy powder, etc. Its continuous availability all year round informed the decision to evaluate their nutritional relevance in the production of rabbits. Results (experiment I) showed that rabbits fed 0 and 10% CPH diet had higher average final body weight and average daily weight gain than rabbits fed 20% and 30% CPH diets. Increasing levels of CPH in the diets had no significant effect (P>0.05) on the average daily feed intake, daily protein intake and protein efficiency ratio. Differences between the treatments in nutrient digestibility coefficients were significant (P<0.05). Rabbits on 10% CPH diet had higher nutrient digestibility coefficients than those on 20% and 30% CPH diets. Generally, digestibility coefficients decreased as the level of CPH in the diets increased beyond 10%. The inclusion of CPH in the rabbits’ diet resulted in the reduction of the cost of producing rabbits in terms of feed cost per kg weight gain. Dietary treatments did not have any adverse effect on such haematological values as the Hb, PCV, RBC, MCH, MCHC and MCV of rabbits. However, the WBC was observed to decrease at the 30% level of inclusion. Data on carcass and organ weights showed that rabbits fed 0 and10% CPH diets had comparable live body and this was higher than that of rabbits fed 20% and 30% CPH diets. Similarly, rabbits fed 30% CPH diet had higher dressed carcass weight and dressing percentage than those fed other diets. Dietary treatments had no significant effect on organ weights.
In experiment 2, rabbits fed the 10, 20 and 30% SBH diets had comparable average final body weight, feed conversion ratio, and daily protein intake with the control diet. No significant (P>0.05) differences were observe among rabbits in daily feed intake and average daily weight gain. Rabbits fed 10% SBH diet had similar crude protein, crude fibre and nitrogen-free extract digestibility coefficients with those on the control diet. The digestibility coefficients of the 20% and 30% SBH diets were significantly (P<0.05) higher than those of the 0% and 10% SBH diets. Inclusion of SBH in the diets reduced significantly the cost of production in terms of feed cost per kg weight gain and thus spared the use of rather expensive soybean meal. This reduction in feed cost per kg weight gain was more pronounced in the 20% SBH diet. The inclusion of SBH in the diets did not have any adverse effect on haematological values among all the treatments. The weights of heart, liver, kidney, lungs, and intestine were not significantly (P>0.05) affected by dietary treatments. Rabbits fed 20% SBH diet had superior live body weight while rabbits on 10% SBH diet had significantly (P<0.05) higher dressed carcass weight and dressing percentage than those on other treatments.
Generally, the overall performance of rabbits fed the soybean hull based diets was not inferior to that of rabbits fed the control diet.
CONCLUSION
Results from this study show that up to 10% cowpea hull can be successfully incorporated into the diet of rabbits without any adverse effect on growth performance, carcass yield, internal organ weights and haematological parameters. It is evident also from the results obtained in this study that up to 30% soybean hull can be included in rabbits’ diet without any deleterious effect on growth performance, haematology and internal organs of rabbits. The use of these hulls in commercial quantity when compounding diets for rabbits could also reduce costs and production and make rabbit products available at cheaper prices in such developing country as Nigeria where these hulls are readily available and prices of conventional feed ingredients are on the high side.
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