Nutritional composition, in vitro gas production and in sacco degradability of processed Croton megalocarpus nuts for ruminant feeding

Abstract

This study was conducted to evaluate the effects of processed croton nut on chemical composition, in vitro gas production and in sacco degradability. Four forms of croton nut namely: whole nut (WN), peeled nut (PN), De-husked nut (DhN) and De-fatted seed (DfS) were subjected to proximate analysis, Van Soest fibre fractionation, mineral composition analysis, phytochemical and aflatoxin tests. Degradability analyses were conducted using in vitro gas production and in sacco degradability techniques. Defatted seeds recorded significantly high level of CP and NFE (198 g/kg and 174 g/kg), whereas, ash content and ether extract (EE) were significantly high in WN (59 g/kg) and DhN (362 g/kg) respectively. Low fibre fractions of NDF (556 g/kg) and ADF (490 g/kg) were observed in DhN, while the mineral content was high in DfS which had calcium at 2.13 g/kg and phosphorus at 5.04 g/kg. High level of flavonoid was recorded in WN (124 g/kg), whereas low level of alkaloids was found in DfS (60 g/kg) and tannins in PN (7.1 g/kg). The potential in vitro gas production (a+b) was highest in DfS (22.2 ml/0.2 gDM) while potential in sacco degradability (a+b) was highest in DhN (58.4 %). High level of organic matter digestibility (OMD) (41 %) was observed in DfS. At kp=0.025 rumen outflow rate, DhN had the highest effective degradability of dry matter (56.6%), while the rate effective crude protein degradability was 80.0 %. Processing through peeling and dehusking improved the protein, energy and mineral content of DhN and DfS while crude fibre content reduced. Nutritional composition and degradability characteristics of all forms of croton nuts imply that they could be used in a total mixed ration (TMR) to supply requisite nutrients for maintenance of ruminant animals, while DhN and DfS could be used to supplement energy and protein for increased productivity.