Calorimetry, chemical composition and in vitro digestibility of sugarcane treated with calcium hydroxide

Abstract

Sugarcane is a source of roughage in animal feeding. It presents high production per unit of cultivated area, relatively easy cultivation and low cost of production per hectare, and better quality and a high dry matter (DM) yield in periods when forage is scarce. This study aimed to evaluate the effect of increasing levels of calcium hydroxide (Ca(OH)2) in sugarcane forage on chemical composition, in vitro digestibility values of DM, neutral detergent fibre (NDF) and acid detergent fibre (ADF), and kinetics of thermal decomposition processes of weight loss and heat flow. Sugarcane was collected close to the ground and 50-kg heaps of the fresh material were formed and mixed with four doses of Ca(OH)2 (0, 8, 16 and 24 g kg–1 sugarcane). Concentrations of NDF and ADF decreased linearly with increasing amount of Ca(OH)2, whereas concentration of hemicellulose increased linearly. In vitro digestibilities of DM, NDF and ADF were enhanced in a quadratic manner with increasing amounts of Ca(OH)2. The release of heat, measured by ΔH, increased linearly with increased Ca(OH)2 levels, likely due to enhanced digestibility of the fibre components. Weight loss decreased linearly between 272.2°C and 397.7°C with increased amounts of Ca(OH)2 added to sugarcane, likely due to changes in cellulose structure, which became denser and thermodynamically more stable than native cellulose following the alkaline treatment. Calcium hydroxide changed chemical composition and digestibility of the fibrous fraction of sugarcane, resulting in better nutritional value. The greatest release of heat and highest in vitro digestibility of fibre were observed when adding 15.2 g Ca(OH)2 kg–1 sugarcane; therefore, this dose is recommended to enhance the nutritive value of sugarcane as ruminant feed.

Agronomical and breeding approaches to improve the nutritional status of forage crops for better livestock productivity

“…Daur and Bakhashwain (2013) reported that humic acid 25 kg/ha had improved N, P, K, Ca, Mg and CP content in fodder maize. Several other studies also reported that the application of fertilizers (nitrate, urea, K and Ca) had improved the nutritional quality by reducing oxalic acid, an anti-nutritional compound (Dias et al, 2018;Jayanegara et al, 2017;Rahman & Kawamura, 2011). Chen et al (2017) reported that application of Mg fertilizer had improved pigment composition, root and shoot biomass; N, P and Mg contents; plant stoichiometry; the activity of arbuscular mycorrhizal fungi (AMF); and rhizobium in maize and soybean (Glycine max).…”

Urban sewage sludge stabilization by alkalization-composting-vermicomposting process: Crop-livestock residue use

“…This is because the addition of an alkaline agent, such as lime, for at least two hours, increases the pH up to 12 and maintains it constant for several days [9][10][11], altering the colloidal nature of pathogenic microorganisms' cellular protoplasm lethally [2]. In an agricultural context, alkalization with hydrated lime solubilizes structural carbohydrates and lignin from sugarcane (Saccharum officinarum) [12], caused by the thermo-decomposition process, verified by the energy release [13]. These processes speed up the mineralization of organic compounds during vermicomposting, while rapid changes in pH do not allow bacteria to adapt to this environment, impacting growth and spore formation and promoting its lethality [14].…”