Cassava wastewater can be safely used in the diet of feedlot lambs

Abstract

Cassava wastewater is a potential environmental pollutant, which can become a serious issue when improperly disposed into water bodies due to the toxic effects of cyanogenic glycoside. However, the presence of organic nutrients (starch and soluble sugars, mainly) supports the possibility of using this by-product in animal feeding. This study was conducted to examine the intake, apparent digestibility, performance, and carcass characteristics of feedlot lambs fed diets with increasing concentrations of cassava wastewater. The experiment involved 35 uncastrated Santa Inês crossbred lambs at approximately 3 months old, with an average bodyweight of 20 kg (standard deviation ± 3.4 kg). Diets were formulated with hay of cassava shoots (roughage), a maize- and soybean-based concentrate (50:50 roughage-to-concentrate ratio), and cassava wastewater at 0, 12, 24, 36 or 48 g kg−1 of the total diet (as-fed basis). Dietary inclusion of cassava wastewater led to a linear decrease (P < 0.05) in the intakes of dry matter, organic matter, crude protein, neutral detergent fibre, non-fibrous carbohydrates, and total digestible nutrients. Ether extract intake was not significantly (P > 0.05) influenced by cassava wastewater inclusion in the diets. There was no influence of cassava wastewater on the apparent digestibility of the nutritional components or on any parameter related to animal performance or carcass characteristics. Depending on the quantity, the use of cassava wastewater does not affect the feedlot performance of lambs. Cassava wastewater can be included in feedlot finishing diets at a level of up to 48 g kg−1 (as-fed basis).