Introduction
Nigerian intake of animal protein is 15 g per day, which is far below the recommended minimum level of 35g per day of animal protein intake according to FAO (2003) figures. The main reason for this poor intake of animal protein is poor livestock productivity, which is as a result of poor nutrition, breeding, management and disease control. Cassava production was 41.6 mill tons in 2005 but currently it stands at 54 million tons (Elemo, 2013 unpublished; IITA, 2013). Okara is a by-product of soybean processing; it is the solid residue remaining after making soymilk (Jimenez et al., 2008). Okara contains shell, husk or hull of ground soybean. It is beige in colour, and has a light, crumbly, fine grained texture like grated coconut (Espinosa and Ruperez, 2009). Okara according to O’Toole (1999) is both a source of energy and protein. This soybean waste is used most extensively as a source of energy and protein, especially in poultry diets and piggery production. Its crude protein content ranged between 22%~26% according to O’Toole (1999).

Nigeria is the world’s largest producer of cassava and about 90% of the production is utilized for human consumption internally (Eruvbetine et al., 2003). Cassava root peel constitutes 20.1% of the tuber (Hahn and Chukwuma, 1986) and as such it is a major by-product of the cassava tuber processing industry. Cassava root peel contains 91.8 dry matters, 8.4% ash, 14.0% starch, 3%~6.0% crude protein, 1.5% ether extract, 37.4% crude fibre, 72.1% NDF, 61.7% ADF and 34.2 Lignin (Blank, 2009). However, it has higher hydrogen cyanide (HCN) content than the pulp. Locally, it is used in farms to raise pigs, chickens, sheep and goats (Tewe and Egbunike, 1992). Different authors had used cassava peel at different percentages but not with okara inclusion. This research therefore is set out to see the response of broiler chickens to cassava peel and okara inclusion in the diet.

1 Material and Methods
The experiment was carried out in the deep litter section of the Animal House of the Food Department of the Federal Institute of Industrial Research, Oshodi (FIIRO) Lagos State, Nigeria with good ventilation and wood shavings litter material at 8cm depth. One hundred and eighty (180) day old Marshall broiler chicks were used for the study. The birds were weighed on arrival at the farm (initial weight) and weekly thereafter. Using a completely randomized design (CRD) arrangements, the birds were assigned to six treatments with three replicates of ten birds each. Analysis of variance was done using SAS (2007) and significant differences were separated using the Duncan Multiple Range Test (DMRT). Birds were housed in pens on deep litter and were brooded for two weeks before allotting to their respective pens after brooding stage. At the starter and finisher phases of growth, a compounded broiler starter and finish feed were given (Tables 1 and Table 2). The vaccination programmes was strictly adhered to and water was provided ad libitum.

Table 1 Gross Composition of the Starter Diets Used in the Experiment (g/kg)

Table 2 Composition of the Finisher Diet Used in the Experiment (g/kg)

 
2 Results and Discussion
The results of the determined analysis (Table 3) showed that the crude protein content of cassava peel was 3.09% while that of okara was 24.27% which was close to 25.06 and 25.34% reported by O Toole, (1999) and Espinosa et al. (2009).

Table 3 Determined Analysis of the Test Ingredients

 
The growth performance results (Table 4) showed that the final liveweight showed significant difference (P<0.05) among the treatments. A significantly highest (P<0.05) highest final live weight was recorded at the 40% inclusion level with a value of 2055.20 kg compared to a significantly lowest value of 1805.40g in the 30% inclusion. There was a significantly higher feed intake value of 125.05 g recorded at the 50% inclusion but this did not transmit to a higher weight gain which could be due to higher crude fibre content in the diet compared to others. The feed conversion ratio (FCR) showed significant differences (P<0.05) where the best FCR value of 2.90 was recorded in the 40% inclusion compared to 3.57 in the highest inclusion level (50%) and 3.24 in the control (0%). The cost of feed per kg weight gain was significantly lowest at the 40% inclusion level (N130.54) compared to N175.11 and N163.34 recorded at the 50% and 0% inclusion level.

Table 4 Effect of feeding treatments on overall growth performance and cost effectiveness of broiler chickens

 
The results of the blood profiles of the treatments (Table 5) showed that the white blood cells values were not significantly (P>0.05) different from one another though 40% inclusion level recorded the highest value of 31.82 cu mm3 compared to the lowest value of 29 cu mm3 in the control. The values obtained are close, this could mean that there were no hydrocyanide traces in the blood as this was expected to shoot up the WBC values of the birds if highly present. The serum creatinine of the 40% inclusion was significantly (P<0.05) highest with a value of 1.48 mg/dl compared to a significantly (P<0.05) lowest value of 1.34 mg/dl recorded the 0% inclusion. The packed cell volume, red blood cell and the mean cell volume values were not significantly (P>0.05) affected by the inclusion levels (Table 6).

Table 5 Effects of feeding treatments on haematology and serum chemistry of broiler chickens

Table 6 Effects of feeding treatments on digestibility trials of broiler chickens

 
The digestibility of the feeding treatments showed that the 0 to 40% inclusions were not significantly (P>0.05) from one another compared to a significantly (P<0.05) lower value recorded in the 50% inclusion which was directly reflected in the lower growth performance recorded by the birds.

3 Conclusion
It is concluded that okara and cassava peel inclusion in the diet of finishing broiler chickens up to 40% inclusion had a positive effects on the growth performance of the broiler chicks. It posed no negative or any deleterious effect on the feed efficiency and helps to reduce the cost of feeding. The digestibility coefficients showed that there was a higher dry matter digestibility especially at the 10% and 40% inclusion compared to that of the 50% inclusion. Also, the blood profiles showed that the okara and cassava peel meal are well processed since the red blood cells and the white blood cells are all within an acceptable ranges.

Acknowledgements
We want to thank the Director- General, CEO of Federal Institute of Industrial Research Oshodi (FIIRO) Lagos State for her interest in giving the grant in financing and visiting the research centre during the course of this research work with the management staff of the Institute. We appreciated all the support.

Also, the Acting Director of Food Division for her visits and encouragement during the course of the research. The research team members are all appreciated for their serious mindedness and discipline to make sure the research attain this international success. We thank you all.

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