Detoxified Castor Bean Meal as a Protein Supplement in Sugarcane Silage for Sheep: Intake, Digestibility, and Performance

Castor (Ricinus communis) is a toxic seed used to extract oil for the chemical industry, with castor meal as a by-product. A recently developed industrial method allows its detoxification, enabling its use as a protein-rich feed for ruminants. This study evaluated the safety of detoxified castor meal based on intake, digestibility, and performance of sheep fed sugarcane silage containing increasing levels of this ingredient. The detoxified castor meal, supplied by an oil extraction industry, underwent no additional detoxification treatment. Twenty-four intact male sheep were randomly assigned to diets containing 0%, 10%, 20% or 40% fresh matter castor meal in sugarcane silage. Diets were balanced with soybean meal and ground corn. After 60 days of feeding, no signs of intoxication were observed. Crude protein (CP) intake decreased from 0.157 to 0.128 kg/day (p = 0.03) and ether extract (EE) intake from 0.068 to 0.044 kg/day (p = 0.04). Crude protein digestibility declined from 754 to 473 g/kg (p < 0.01), and EE digestibility from 813 to 725 g/kg (p = 0.02). All other intake, digestibility, and performance variables were not significantly affected (p ≥ 0.05). Industrially detoxified castor meal was shown to be a safe additive in sugarcane silage up to 40% by fresh matter, with no adverse effects on sheep performance.