UTILIZATION OF FERMENTED CASTOR OIL SEED ( RICINUS COMMUNIS , L ) MEAL IN DIETS FOR COCKEREL CHICKS

The effect of including 0, 50, 100 and 150 gkg-1 of fermented castor oil seed (FCSM) meal in the diets of 160 day old chicks of Nera strain, on performance, nutrient digestibilities, haematology and carcass yield, was assessed for 56 days. The final live weight, weight gain, feed intake and feed conversion ratio were affected (p<0.05) by treatments. The final live weight decreased (p<0.05) as FCSM increased in the diets. There were no differences in the weight gain of chicks fed control and 50 gkg-1 FCSM diet. The apparent nutrient digestibility of chicks fed control diets were higher (p<0.05) than those fed other dietary treatments. Chicks fed control diets recorded the highest (p<0.05) carcass yield in terms of plucked and eviscerated weight. These values obtained in chicks fed 50 gkg-1 were higher (p<0.05) than those fed 100 and 150 gkg-1 FCSM. There were no differences in back, breast, gizzard, and intestines weights. The white cell and platelet counts were affected (p<0.05) for chicks fed 100 and 150 gkg-1 FCSM diets. Higher (p<0.05) values of serum creatinine were obtained in chicks fed 100 and 150 gkg-1 FCSM. FCSM could successfully be included in chick starter diets at 50 gkg-1 inclusion.


INTRODUCTION
Plant protein and oil seeds used in livestock feed formulation over the years have suffered serious competition between man, livestock and agro-industries.Hence, there is a need to explore alternative protein sources to reduce the competition.Castor oil bean (Ricinus communis) is grown in tropical and temperate regions, where the dehulled seeds are processed for use as flavour-enhancing food condition.
Studies in animal nutrition have shown that castor oil bean meal can be used as a protein supplement for ruminants, rabbits, pigs and chicks (Okorie et al., 1985).However, its utilization in monogastrics, especially poultry, has been limited because of possible deleterious effect due to the presence of ricin, a poisonous protein component, ricinine, an alkaloid, and thermostable castor allergen (Vilhjalmsdottir and Fischer, 1971;Okoye et al., 1987).Ricin is a group of phytotoxin which is toxic, antigenic, thermolabile and agglutinating red blood cell while ricinine is a white alkaloid usually extracted with the oil (Jerkins, 1963).The complex allergen represents about 12.5% of weight of the cake.It is a protein composed of nontoxic, thermally stable, but with allergenic actions (Carrielo-Gama, 2006;Machado and Silver, 1992).The castor allergen according to Thorpe et al. (1988) caused congestion of the nose, eyes, resulting in vomiting, gastroenteritis, hepatic and renal damage.
In the quest to removing these deleterious factors, various aqueous heating, combined extraction and heat treatment procedures have therefore been developed.Adedeji et al. (2006) assessed the utilization of boiled castor seed cake in diet for weaner rabbits and observed a tolerant level of not more than 15%.The feeding value of castor bean in diets for growing chicks can be improved by roasting.Puttaraj et al. (1993) explored the reduction of the antinutritional factors using lime cum heat treatment and obtained a good response with rats.Roasting of the castor seed followed by oil extraction in the hammer mill resulted in the reduction of the deleterious factor (Pablo et al., 1976).
Researches are currently on going to discover physical and chemical treatments (Anandan et al., 2005) that will improve the inclusion of this meal in poultry nutrition while maintaining its nutritive quality.Ani and Okorie (2002) in their studies explored the possibility of reducing these deleterious factors by cooking and dehulling the seeds and they reported a reduced feed intake and weight gain in finishing broilers fed 15% inclusion level and above.
However, there is limited information on the possible reduction of the deleterious factor using locally acceptable medium of soaking and natural fermentation which could be acceptable by peasant and large scale farmers.Hence, this study was carried out to ascertain the effect of replacing soybean meal with graded levels of air tight, water soaked, naturally fermented castor oil seed (FCSM) and its effect on the performance, nutrient digestibility, haematological parameters and carcass characteristics of cockerel starters.

TEST INGREDIENT
The castor seed used in the study was obtained from the Raw Material Research and Development Council, Kaduna, Nigeria.The seeds were soaked in water to allow natural fermentation at a ratio of 1:4 under an air tight environment for 5 days.The water was drained off at end of the fermentation process, seeds were washed several times with water to remove the sour taste and fermenting odour.The washed seeds were then sun dried to a moisture content of 100-120 gkg -1 .The seed were later hammer milled and screw pressed to obtain the meal while the oil drained off using the manual hydraulic extractor.The milled samples were later packaged and used to compound the experimental diets.

EXPERIMENTAL MANAGEMENT AND DESIGN
One hundred and sixty day old cockerels of Nera strain were allotted to four diets containing 0, 50, 100 and 150 gkg -1 FCSM in a completely randomized design.Each dietary treatment consisted of 40 birds replicated 4 times with 10 birds per replicate.The experiment lasted for 8 weeks during which feeds and water were offered ad libitum.Feeding was done daily while the feed intake on a daily basis was computed as the difference between the feed offered and leftovers.The chicks were weighed weekly while weight gain was computed as the difference between the final liveweight and initial weight.Feed conversion ratio was computed as the ratio of the total feed consumed to weight gain.The proximate composition of the feed samples were determined according AOAC (1990).

MEASUREMENT OF NUTRIENT METABOLIZITY
At the end of the experiment, two birds per replicate were housed individually in metabolic cages.Three days acclimatization period were allowed prior to the start of the trial.Known weights of feed were given the birds and total feacal droppings were collected, dried and samples assayed on dry matter basis for proximate constituents.The proximate constituents were used to calculate the nutrient metabolizity of each constituent.Gross energy of the feed and faecal droppings was determined using the calorimeter bomb.

SERUM AND HAEMATOLOGICAL PARAMETERS
Blood samples (2.5 ml) were collected at 8 weeks according to the procedure of Varley et al. (1980) via the wing vein of two birds per replicate into ethytlene diamine tetraacetic acid (EDTA) bottles for haematological analysis while another set were collected into vials without EDTA and allowed to clot as outlined by Baker and Silverton (1985).The serum from the clotted blood samples were used to determine the serum biochemistry.The packed cell volume (PCV), red blood cell (RBC), haemoglobin (Hb) and white blood cell (WBC) were determined using Wintrobes microhaematocrit and improved Neubauer haemocytometer as described by Baker and Silverton (1985).The total serum protein (TSP) was determined according to the method of Colowich and Kaplan (1955) while the serum albumin (SA) and globulin (SG) was determined using bromocresol purple method of Varley et al. (1980).Serum creatinine (SC) was determined using the principle of Jaffe reaction as described by Bonsnes and Tausslay (1945) while the serum uric acid (SUA) was determined using the Kit (Quinica clinica spam) as described by Wootton (1964).

CARCASS EVALUATION
At the expiration of the experiment, 8 birds per treatment (2 birds per replicate) were selected and used for the carcass evaluation.The birds were slaughtered via neck slit, defeathered, dressed and cut into parts according to the procedure outlined by Oluyemi and Robert (1979).Each of the parts were weighed and recorded.

STATISTICAL ANALYSIS
Data collected were laid out as completely randomized design and analysed with oneway Analysis of Variance using SPSS (1999).Model sum of squares were partitioned to test linear, quadratic and cubic trend (Gomez and Gomez, 1983).

CHEMICAL COMPOSITION OF FERMENTED CAS-TOR SEED MEAL (FCSM)
Table I shows the proximate composition of the FCSM used in this study compared with soya bean meal.FCSM has a lower crude protein and P level of 242.0 gkg -1 and 1.70 gkg -1 than SBM which was reported by Aduku (2000) to have crude protein and P level of 440.0 gkg -1 and 6.0 gkg -1 .However, the ether extract, ash, NFE, dry matter, crude fibre and Ca contents of FCSM were found to be higher than that of the SBM.The proximate composition obtained for FCSM in this study was similar to the findings of Okorie et al. (1987) who reported that the crude protein of castor oil seed meal ranged between 240-320 gkg -1 depending on processing.The crude protein, crude fibre, ether extract, ash and nitrogen free extract values obtained in this study were however lower than the value reported by Adedeji et al. (2006) who reported values of 390, 190, 70, 80 and 430 gkg -1 respectively.The composition of the experimental diets as revealed in table II shows that the metabolizable energy of the diet reduced as the level of FCSM inclusion increased in the diet from 10.94 MJ/kg (in control) to 10.54 MJ/kg (150 gkg -1 FCSM based diet).This was due to the fact that FCSM had a lower gross energy than SBM and replacing SBM with FCSM will eventually leads to a lower energy based diet.

DIGESTIBILITY
Performance characteristics and nutrient digestibility of cockerel chicks fed FCSM based diet is shown in table III.The final live weight and average weight gain of the chicks reduced (L, Q; p<0.05) with increased dietary level of FCSM.However, the average weight gain recorded in the control diet and chicks placed on 50 gkg -1 FCSM based diet recorded similar values.The similarity observed among the groups fed control and 50 gkg -1 FCSM based diets could be related to their similar energy values, since chicks have been reported to consume feeds in order to first fulfill their energy requirements (Gibson et al., 1989).The linear (L; p<0.01) and quadratic decline (Q; p<0.05) in the feed intake and weight gain observed with corresponding increase in FCSM inclusion level from chicks fed control diet to those fed with 100 gkg -1 FCSM was in agreement with the findings of Okorie et al. (1987) who reported that broiler starter fed heat treated castor seed meal based diets at 150 and 200 gkg -1 inclusion level exhibited a reduced performance in terms of feed intake, weight gain and feed conversion ratio.This could    also be due to the residual effect of the antinutritional factors present in the meal which increased with increase in the level of FCSM in the diet.There has been reports of reduced growth response in poultry due to residual effect of castor allergen in castor bean meal based diets (Okorie et al. (1987); Margeret et al., 1979).As the FCSM inclusion level increased, there was also a dilution effect of fibre on the diets reducing the utilization of other nutrients in the body of the chicks.This is in agreement with the report of Longe and Ogedengbe (1989) which stated that diluting diets with fibre source contributed immensely to the bulkiness of the resultant diets, hence reducing nutrient digestibilities.This dilution effect reduced the actual nutrient intake by the birds most especially protein intake.This caused the reduced linear and quadratic trend in (L, Q; p<0.05) protein digestibility and dry matter digestibility as the level of FCSM in the diet increased.This reduced nutrient digestibility and intake as FCSM inclusion increased could go a long way to reduce the actual protein intake and also lead to a lower resultant body weight gain of broilers as FCSM inclusion level increased.This was also confirmed by the reports of Gibson et al. (1989) who reported that body weight gain of broilers reduced with decrease in dietary protein and performance.The absence of mortality recorded in this study however was contrary to the reports of Ani and Okorie (2002) who reported that 150 gkg -1 castor oil bean based diet caused (p<0.05)mortality in chicks.The absence of mortality in this study could be due to fermentation which reduces the toxicity level of the antinutritive factors in castor oil bean.Significant differences observed in this study for feed intake, weight gain and feed conversion ratio were similar with the report of Ani and Okorie (2002).
The dietary treatment has no effect on ether extract digestibility while exhibiting a quadratic increase (Q; p<0.05) in crude fibre digestibity.However, the dry matter digestibility and crude protein digestibility reduced with increase in FCSM inclusion from 684.9 gkg -1 and 677.5 gkg -1 to 500 gkg -1 and 480 gkg -1 respectively.Birds fed control diet had higher values of (L, Q; p<0.05) crude protein digestibility than the rest dietary treatments.The effect of reduced linear (p<0.05)dry matter digestibility and crude protein digestibility (L,Q; p<0.05) reported in this study could be attributed to the effect of residual ricin-an antinutritional factor in castor oil bean.Ricin has been shown to interfere with digestion of nutrient, absorption and nutrient utilization.The reduced digestibility values observed could also be due to the increasing fibrous nature of the diet as FCSM inclusion increased (Longe and Ogedengbe, 1989).

HAEMATOLOGICAL PARAMETERS, SERUM BIOCHEMISTRY AND CARCASS CHARAC-TERISTICS
The haematological and carcass characteristics of cockerel chicks shown in table IV revealed no significant effect on packed cell volume (PCV), haemoglobin (Hb), red blood cell (RBC), neutrophil, eosinophil, basophil, total serum protein, serum albumin, serum globulin and serum uric acid.However FCSM inclusion revealed a significant (L; p<0.01;Q; p<0.05) effect on white blood cell (WBC), platelet (Pl) and serum creatinine with their values increasing as FCSM inclusion increased from 6.0 x 106/mm 3 , 210.5 x 109/l and 0.55 mg/dl in chicks fed control diet to 6.25 x 106/mm 3 , 226.5 x 109/l and 0.79 mg/dl respectively in chicks fed 150 gkg -1 FCSM diet.WBC has been known to play an important role with the production of antibodies and recognition of foreign bodies (Eggum, 1989).Values recorded were still within the normal range for birds.The increase in WBC values as FCSM inclusion increased has been attributed to a physiological efforts of the birds in increasing its immunity after a lowered immunity caused by the deleterious factors in castor bean.High values of WBC have been found in infectious inflammatory conditions, under stress conditions, in association with allergy, parasitism and chronic tissue damage (Eggum, 1989).Increased blood platelet production could be as a result of increasing physiological stress created in the birds as FCSM inclusion increased.Marked increase in thrombopoiesis has been linked with stress, occlusion of large vessels, chronic inflammatory disease and iron deficiency (MacWilliam et al., 1982).Jacobs (1966) reported a positive relationship between erythrocyte and blood platelets production.Blood platelets values of chicks placed on the control diet and 50 gkg -1 FCSM were similar with close range and differs widely from those on 100 and 150 gkg -1 FCSM based diet.The higher (p<0.05)values of creatinine obtained in chicks fed 100 and 150 gkg -1 is an indication of muscle wastage in the chicks due to treatment imposed.Serum creatinine levels indicate the extent of muscle degradation in animals.
When the vales are high, it shows a high degradation of muscle phospho-creatinine to form creatinine and the values varies from 0.50 -1.35 mg/dl (MacWilliam et al., 1982).
The findings in this study was contrary to the report of Ani and Okorie (2002) who reported higher (p<0.05)packed cell volume (PCV) in birds fed 0, 10 and 15 gkg -1 castor bean meal (CBM) diets.
The result of the carcass characteristics shows that the plucked weight, breast weight and eviscerated weight reduced significantly (L; p<0.05) as FCSM inclusion level increased in the diet.Back weight also reduced significantly (L, Q; p<0.05) as FCSM inclusion level increased in the diet The reduction in carcass weight was as a result of reduced weight gain and final live weight which later translated into reduced carcass and cut parts weight.
In conclusion, FCSM could be included at 50 gkg -1 level inclusion in starting cockerels without any deleterious effect on growth response, nutrient digestibility, haematological parameters and carcass yield.

Table II .
Gross composition of diets.

Table III .
Performance characteristics and nutrient digestibility in cockerel chicks fed experimental diets.(Rendimiento y digestibilidad de nutrientes en pollitos alimentados con las dietas experimentales).