Investigations on nutritional aspects of Cassava (Manihot esculenta Crantz) Leaf and its enrichment

Abstract

The study entitled “Investigations on nutritional aspects of cassava (Manihot esculenta Crantz) leaf and its enrichment” was carried out at the Division of Crop Utilization, ICAR – Central Tuber Crops Research Institute, Sreekariyam, Thiruvananthapuram during the year 2018 – 2019. Cassava (Manihot esculenta Crantz) is a major stable food crop for sustainable agricultural practice and food security in both developing and under developed countries. Cassava leaves are rich in protein, carotenes, vitamins B1, B2, and C, and minerals such as calcium, magnesium and also rich in anti-nutritional factors such as cyanogens. Efficient use of cassava products resulted in reduced feed costs. With proper processing the inclusion levels of cassava leaves in diets can be increased and can be used as an alternative energy source. The total fresh weight and dry weight (in grams), and number of leaves (per plant) were studied. For the ten different genotypes the fresh weight and dry weight of the leaves ranged from 168.33 g – 398.77 g plant-1 and 129.67 to 44.57 g plant-1. The number of leaves per plant also varied greatly in number per plant of each genotypes. The crude fibre content of the leaves ranged from 6.4 to 10.3% (Oke, 1966). In the present study the fibre content of leaves was obtained ranging from 18.73 to 48.67% for different genotypes. The lignin content in cassava leaves determines its anti nutritional quality. Higher content of lignin in feed limits its consumption. The lignin content obtained from the study ranges from 0.06 – 0.15 g/g for different genotypes. The linamarin content present in the leaves of the ten cassava genotypes were analysed and it ranged from 0.75 to 6.04 mg g-1 on a fresh weight basis. On a dry weight basis the content ranges from 0.34 to 1.2 mg g-1. The linamarin content at 7th day and 20th day of enrichment of the genotypes H1687 was found to be 0.3549 and 0.3504 mg g-1 while for the genotype Malayan 4 it was found to be 0.3631 and 0.355 mgg-1 respectively. The content can be reduced greatly as the duration of fermentation increases. The rapid reduction in the level of cyanide 75

after ensiling implies that ensiling is an effective way of reducing HCN in cassava leaves and roots before feeding them to dairy animals. In the present study, different genotypes of cassava leaves showed that the content of trypsin inhibitors reaches up to a maximum value of 33.41% for the genotype Sree Jaya (three month old plants). The protein content of the cassava leaves was found to be higher in all genotypes. The protein content of the enriched samples was found to be reduced at 7th day and 20th day when compared to the samples at 0th day. Addition of additives such as molasses resulted in reduction of protein content in the silage, The presence of high content of mineral elements particularly Ca, Mg, K elements in cassava leaves confirms its importance as a rich source of mineral elements. The mineral elements Cu, Zn, Fe, Mn, P present in leaves ranges between 24.7 to 29.7 (mg/L), 123.2 to 230.9 (mg/L), 420 (mg/L) to 476.7 (mg/L), 151.3 (mg/L) – 385.9 (mg/L) and 1.53395 (mg/L) -2.9466 (mg/L) respectively. The mineral elements was found to have a slight decrease in the content on enrichment at 7th and 20th day when compared to initial days. For the present study urea was added as N source, yeast and molasses are also added into the silage for the enrichment purposes which enhance the fermentation rate of the silage that resulted in a characteristic odour, flavour and colour of the silage. The H1687 and Malayan 4 (M4) genotypes having high dry matter and protein content is suitable for use as leaf meal and preparation of silage from cassava leaves.