Chemical composition of Manihot esculentum crantz (var. umucass 36)
Cassava (Manihot esculentum) is one of the most drought tolerant crops, adapted to varying agro-ecological zones and has a high potential for livestock and poultry production in Nigeria. Thus, proximate, macro and micro minerals, anti-nutrients, gross energy and amino acid profile of cassava (Manihot esculentum crantz var. UMUCASS 36) were carried out using freshly harvested cassava. The cassava root was washed, peeled and chopped into small pieces. This was oven dried and milled to form cassava root meal (CRM). The harvested leaf and petiole was chopped, oven dried and milled as cassava foliage meal (CFM). The tender, green apical part of the stem was equally harvested, chopped, oven dried and milled as cassava tender stem meal (CTSM) while the cassava composite meal(CCM) was a mixture of the root meal, foliage meal and the tender stem meal at the ratio of 10:4:1 respectively. The proximate, gross energy, macro (Na, P, K, Ca and Mg) and micro (Fe, Zn, Mn and Cu) minerals, anti nutritional factors (hydrocyanic acid, tannin and trypsin inhibitor) and the amino acids were determined in line with the internationally accepted standard. There were significant (P<0.05) differences among various parts of the UMUCASS 36 cassava for all the parameters considered. The crude protein was least in cassava root meal (2.29%) and best in cassava foliage meal (21.79%). CCM had the highest (P<0.05) gross energy of 3.77kcal/g. CFM had the best contents of sodium (0.27%), potassium (0.88%) and phosphorous (0.38%).CRM had the highest value of calcium (0.29%), CTSM (potassium, 0.88%) and CCM (magnesium, 0.34%). In micro mineral contents, significant(P<0.05) differences existed across the parts examined. CFM was superior in both iron and zinc contents while CTSM had best values of copper and manganese. Hydrocyanic acid value ranged from 1.26mg/kg in CFM to 6.57mg/kg in CCM while trypsin inhibitor had highest value of 9.62TIU/mg in CRM and CFM had tannin value to be 0.086% being the highest. All the anti-nutritional factors measured were at tolerable levels to broiler chicken. Percentages of amino acids like arginine, cysteine, histidine,
phenylalanine and valine in leaf meal were high with these values 6.46, 3.09, 1.34, 3.14, and 8.27% respectively. The nutritive contents of UMUCASS 36 revealed that the root meal with gross energy of 3.66Kcal/g is a potential energy source and therefore can be used as an energy source in poultry ration. The high content of crude protein and its attendant amino acids in the UMUCASS 36 foliage meal placed it at a better level for consideration as replacement for the expensive soybean.
Keywords: UMUCASS 36, proximate composition, minerals, anti-nutrients, amino acid