DEVELOPMENT AND NUTRITIONAL EVALUATION OF “CASIYEAST” (A CASSAVA SIEVATE AND BREWERS SPENT YEAST COMBINATION) AS A FEED RESOURCE FOR RABBITS

ABSTRACT

The study was initiated to determine the chemical characteristics of cassava sievates and brewers spent yeast as well as the nutritive value of “casiyeast” ( a developed feed grade resource which is a combination of cassava sievates and brewers spent yeast) in rabbit diets. Also, to compare the effects of feeding rabbit diets containing two levels of three feed grades of casiyeast 25%, casiyeast 50% and casiyeast 75% as a gradual replacement of soyabean meal in the diets on their performance characteristics, some blood metabolites and carcass characteristics. Cassava sievate samples obtained from four different locations namely Agbarho, Mosogar, Warri and Benin City were sundried and screened for locational differences in chemical characteristics. The physical and chemical characteristics of brewers spent yeast was also evaluated. A mixture of cassava sievates and brewers spent yeast at the three grades were Casiyeast 25% (75% cassava sievates + 25% Brewer spent yeast), Casiyeast 50% (50% cassava sievates + 50% Brewers spent yeast) and Casiyeast 75% (25% cassava sievates + 75% Brewers spent yeast) evaluated chemically.

The casiyeast experimental diets (2700/KCalME.kg ^-1 and 18%Crude Protein) (CP) were formulated by proportional replacement of soyabean meal with “Casiyeast” on weight-for-weight basis. Also 100g Tridax procumbens were served to each rabbit daily.

Result of the survey conducted showed that there were no significant (p>0.05) differences in the chemical characteristics of cassava sievates collected from Agbarho, Mosogar, Warri and Benin City. The obtained mean chemical compositions (%) were Dry matter (DM) = 96.12, Crude fibre (CF) = 1.67, Crude protein (CP) = 1.17, Ether extract (EE) = 0.46, Ash = 1.71 and Nitrogen free extract (NFE) = 91.10, Calcium (Ca) (mg/100g) =19.60, and Total Phosphorus (P) mg/100g 42.14. Brewers spent yeast %DM = 95.00, CF = 0.00, CP = 51.74, EE = 0.92, Ash = 5.58, NFE = 36.76, P (mg/100g) = 63.05, Ca (mg/100g) = 8.16; Casiyeast 25, grade %DM = 95.8, CP = 18.98, CF = 0.56, EE = 0.90, Ash = 2.48, NFE = 72.88, P (mg/100g) = 27.93, Ca (mg/100g) = 37.00; Casiyeast 50% grade %DM 95; CP = 32.38, CF = 0.34, EE = 0.90, Ash 3.50, NFE = 57.88, P (mg/100g) = 56.42, Ca (mg/100g) = 52.86 and Casiyeast 75% grade; CP = 42.67, CF = 0.16, EE = 0.91, Ash = 4.53, NFE = 46.23,P (mg/100g) = 69.88 Ca (mg/100g) = 73.11). Also the hematological results are: Diet 1 Packed Cell Volume (PCV)% = 31.9, Haemoglobin (Hb) (g/dl) = 8.15, Red Blood Cell (x10¹²/l) (RBC) = 8.80, White Blood Cell (WBC) (x 10⁹/l) (WBC) = 7.00 Total Protein (mg/dl^-1) = 6.65, Albumin (mg.dl^-1) = 3.50 Globulin (mg/dl^-1) = 3.05. Diet 2 (PCV)% = 33.45, Hb (g/dl) = 8.73, RBC (x10¹²/l) = 8.35 WBC (x10⁹/¹) = 7.20, Total Protein (mgdl^-1) = 7.00, Albumin (mgd/^-1) = 4.85, Globulin (mgd/^-1) = 2.15 Diet 3 (PCV)% = 36.70, Hb (g/dl) = 9.50, RBC (x10¹²/l) = 8.20 WBC (x10⁹/l) = 7.65, Total Protein (mgdl^-1) = 7.45, Albumin (mg/dl^-1) = 5.00, Globulin (mgdl^-1) = 2.20. Diet 4 (PVC)% = 35.00, Hb (g/dl) = 9.40, RBC = (x10¹²/l) = 8.00, WBC (x10⁹/l) = 8.65, Total Protein (g/dl^-1) = 7.95, Albumin (mgdl^-1) = 5.25, globulin (mg dl^-1) = 2.05. Diet 5 (PVC)% = 35.75, Hb (g/dl) = 8.95, RBC (x10¹²/l) = 9.10, WBC (x10⁹/l) = 8.65, Total Protein (mg.dl^-1) = 7.95, Albumin (mgdl^-1) = 5.25 and Globulin (mg/dl^-1) = 2.70. Diet 6 (PVC)% = 37.75, Hb (g/dl) = 9.55, RBC (x10¹²/l) = 9.00, WBC (x10⁹/l) = 6.70, Total Protein (mg/dl^-1) = 8.05, Albumin (mg/dl^-1) = 5.45, Globulin (mgdl^-1) = 2.60. Diet 7 (PVC)% = 41.65, Hb (g/dl) = 10.65, RBC (x10¹²/l) = 9.25 WBC (x10⁹/l) = 7.40, Total Protein (mgdl^-1) = 8.35, Albumin (mgdl^-1) = 6.1, Globulin (mgdl^-1) = 2.25.There were no significant (P>0.05) differences on the effect of the different grades of Casiyeast on performance indices, carcass and organ characteristics, hematological indices and physical health of the animals though the values obtained for these parameters were even higher in the Casiyeast based diets. No mortality was recorded during the study. The three Casiyeast grades (25%, 50% and 75%) at 30% and 60% levels of inclusion under the condition of this study can replace soyabean meal in practical rabbit diets with biological and commercial effects comparable to 100% soyabean meal in the diet.