Cassava leaves as animal feed: Potential and limitations

Abstract

Abstract:The nutrient composition and potential productivity of cassava (Manihot esculenta Crantz) leaves are examined, and their usefulness as a protein supplement in animal nutrition in the tropics is reviewed. On average, meal prepared from cassava leaves contains (on a dry matter basis) 210 g kg-' crude protein, 250 g kg-' acid detergent fibre, 85 g kg-' ash, 14.5 g kg-' calcium and 4.5 g kg-' phosphorus. Cassava leaf protein is well balanced, except for a deficiency of sulphur-containing amino acids. The presence of hydrocyanic acid and tannins is considered, but a leaf meal with low levels of these anti-nutritional factors may be prepared using simple processing techniques. The most immediate prospects for the use of cassava leaf products are in the following areas: (i) low level inclusion of leaf meal in feed formulations for monogastric animals, and (ii) fresh forage as a protein supplement to low-quality roughages in ruminant feeding. Relevant future research needs are also identified.

Effect of harvest period on the quality of storage roots and protein content of the leaves in five cassava cultivars (Manihot esculenta, Crantz)

“…Cassava plant is cultivated mainly for its storage roots (Ravindran, 1993), and it produces potentially more calories per area unit than any other crop in the world except sugar cane (Cassava, 2000). Energy production from the cassava crop is 250 x 10 3 cal.ha , produced by maize, rice, sorghum and wheat, respectively (Balagopalan et al, 1988).…”

“…However, besides the storage roots being rich in starch, the cassava plant canopy has gained importance because it might be a source of proteins, vitamins and minerals for human and animal nutrition (Carvalho et al, 1985;Carvalho et al, 1993a). Among the reasons for these speculations is the fact that the leaf protein content is high for a non-leguminous crop, being on average around 210.0 g.kg -1 (Ravindran, 1993) although values vary from 147.0 g.kg -1 to 400.0 g.kg -1 in dry matter. The variations have been attributed to several factors, both in the dry matter and starch content in the roots and the cassava leaf protein content, but the most important are those which refer to differences among cultivars, as well as the harvesting period of the storage roots (Jesus et al, 1986;Fukuda and Borges, 1990) and of the canopy (Carvalho et al, 1985;Ravindran, 1993).…”

“…Among the reasons for these speculations is the fact that the leaf protein content is high for a non-leguminous crop, being on average around 210.0 g.kg -1 (Ravindran, 1993) although values vary from 147.0 g.kg -1 to 400.0 g.kg -1 in dry matter. The variations have been attributed to several factors, both in the dry matter and starch content in the roots and the cassava leaf protein content, but the most important are those which refer to differences among cultivars, as well as the harvesting period of the storage roots (Jesus et al, 1986;Fukuda and Borges, 1990) and of the canopy (Carvalho et al, 1985;Ravindran, 1993). Thus studies are needed to establish the most suitable crop stage for harvest by regions and by cultivar that would provide highly nutritious foliage (Carvalho et al, 1991) and storage roots with high dry matter and starch contents (Wholey and Booth, 1979).…”

Effects of Gradual Feed Dilution With Inert or Less Nutritive Materials on Growth Performance, Feed Cost and Meat Organoleptic Properties of Broiler Chicken

“…This suggests that the utilization efficiency of the nutrients was negatively affected when CLM, GLM and SD are used. In fact, CLM and GLM and SD are reported to contain antinutritional factors, such as tannins and alkaloids that can negatively affect digestion, absorption, and nutrient utilization efficiency (Ravindran, 1993;Ranaweera et al, 1981;Osei et al, 1990). In addition, when those materials were used, feed cost per kg of live weight gain was also higher than that of the control diet.…”

Ileal digestibility of amino acids of cassava, sweet potato, cocoyam and erythrina foliages fed to growing pigs

“…In fact, secondary metabolites such as tannins are known to interact with both dietary and endogenous proteins in the digestive tract and cause decreased true AA digestibilities (Kumar and Singh, 1984;Jansman, 1993). Inhibition of trypsin activity by tannins has been reported in vitro (Griffiths, 1986), which may affect the digestibility of CP and AA by growing pig (Oke, 1984;Ravindran, 1993). Tannins increase the amount of specific EPL either by enhancing endogenous secretions and/or by decreasing degradation and re-absorption of endogenous nitrogen (Nyachoti et al, 1997), with negative consequences on AA SID.…”