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.
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 FOUR
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
5 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. This indicates that CPH encourages growth rate as type and quality of feed fed to rabbits has an effect on their growth rate, it could also be said that the test ingredient compares favourable with other non conventional feed ingredients. No significant difference was observed in daily feed intake, protein efficiency ratio (PER) and protein intake (PI). The non significant difference (P>0.05) observed in the feed intake could be due to the fact that the rabbits’ energy requirement 2390-2500 kcal (Aduku and Olukosi, 1990) was met at the different CPH inclusion level of the diet. Cheeke and Amberg (1972) reported that voluntary feed intake increased in rabbits as a means of compensating for lower energy density of the feed. The nutrient content of the CPH based diets could also be said to be sufficient for the weaner rabbits hence the rabbits did not consume more feed inspite of the increase in dietary fibre level.
Digestibility coefficient of cowpea hull based diets.
It could be observed (Table 8) that there were significant differences among treatments in the dry matter, crude protein, crude fibre, ether extract and nitrogen-free extract digestibility. Generally digestibility decreased gradually with increase in the addition of CPH in the diet. Apparently, the increase in the fibre level of cowpea hull based diets occasioned by the increasing level of the CPH in the diet resulted in the gradual decrease in the digestibility coefficients observed. This supports the findings of McDonald et al (2002) that the increasing fibre levels results in the decrease of digestibility. The DM and CP digestibility values obtained in this study were within the range reported by Uko et al. (1999) for rabbits fed cereal by-products as energy source in the diets. But values obtained with fermented and unfermented cocoa pod (Adejinmi et al., 2007) were lower than the value recorded in this study. The difference might be related to the nature of fibres in the two feedstuffs in question. The nature and type of dietary fibres are known to influence digestibility.
The control diets were consistently and significantly better digested than the cowpea hull based diets. Exception to this trend was the similarity observed in dry matter and crude fibre digestibility at the 10% CPH inclusion level. The high nutrient digestibility observed at the 10% CPH inclusion level could mean that at this level of inclusion, rabbits compare favourable with the control diet.
Haematological evaluation
As shown in Table 9, the haemoglobin concentration (Hb), PCV and RBC increased significantly with increasing level of CPH in the diet. However, values obtained ranged within the normal values for rabbit (Mitruka and Rawnsley, 1997; Ross et al., 1979). This implies that the inclusion of CPH in the diets of the rabbits did not reduce dietary protein high quality (Abu et al. 1998) and hence did not have detrimental effect on the haematological indices. Besides, it does appear that CPH was not toxic to the rabbits. Studies have shown that low PCV value for instance indicates the presence of toxic factor such as haemagglutin which is known to have adverse effect on blood formation (Oyawole and Ogunkunle, 1998). The inclusion of 10% CPH in the diet resulted in significant increase in WBC concentration. However, WBC decreased at the 20% and 30% CPH inclusion. Incidentally, the values obtained (3.98 and 4.83 x 103/mm3) are below the normal range reported by Ross et al., (1979). Perhaps, the inclusion of CPH at 20% and 30% levels might have mildly suppressed haemopoietic tissues with the resultant production of lower WBC (Ojebiyi et al., 2007). The fact that there was no evidence of disease infestation within the treatment group could strongly support the lack of significant increase in WBC. Although MCH%, MCHC and MCV values differed significantly among the various treatments, the values obtained in the present study were within the normal range for rabbits
Cost implication of feeding graded levels of cowpea hull to growing rabbits
Increasing levels of CPH in the diets led to reduction in feed cost (Table 10). Inclusion of carrying levels of CPH in the diets also had a significant effect on cost of feed per kg weight gain (N). The highest cost per kg wt gain (N400) was recorded at the 0% inclusion level (control) while the least cost per kg weight gain (N51.65) was recorded at the 30% CPH inclusion level. As the level of inclusion of CPH in the diet increased, feeding the animals with dietary CPH became very economical. Considering the reported finding of Whyte and Wadak (2002) that the cost per unit weight gain increased with increasing level of sweet potato in poultry and rabbit diets, it does seem that it is more economical to include CPH in the diets of rabbits than to include sweet potato in their diets.
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.
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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