Nutrient and feed value analysis in leaves of cassava wild species and cultivars

Abstract

Objective: In order to provide reference for developing cassava leaves as feed resources nutritional components in leaves of cassava wild species and cultivars were studied. Method: Nutritional components including crude lipid, crude protein, soluble sugar, starch, carotenoid and HCN contents in functional leaves of eight cassava germplasms (three cassava wild species and five cultivars) were determined. The expression levels of proteases (UGPase, AGPase, GBSSI and Linamarase) were determined using Western blotting method. Result: Among eight cassava germplasms，wild species Manihot cecropiaefolia Phhl contained the highest starch content in functional leaves, which was 2.5 g/100 gDW, the highest soluble sugar content which was 30.0 g/100 gDW and the highest carotenoid content which wsa 91.9 mg/100 gFW, but protein and hydrocyanic acid contents were at moderate level. Cultivar SC9 contained moderate protein and soluble sugar contents in functional leaves，and the lowest HCN content which was 167 mg/kgFW. According to Western blotting analysis，expression levels of key enzymes, UGPase, AGPase and GBSSI, for sugar and starch metabolic pathway were the highest in M. cecropiaefolia Phhl; while key enzyme Linamarase for SC9 HCN metabolic pathway was the lowest. Expression levels of all proteins were in accordance with related physiological indexes variation trend. Principal component analysis revealed that, the cassava germplasms with high starch and soluble sugar content in leaf were tend to contain low crude lipid content; and the ones with high soluble sugar, crude protein and carotenoid contents would contain low HCN content. Conclusion: Comprehensive nutritional value of functional leaves in cassava wild species M. cecropiaefolia Phhl is high, which may be developed as feed resources for livestock and silkworm. HCN content in cultivar SC9 fresh leaf is low, thus it can be used as feed for silkworm.