Abstract

The nutritional value of sago pith is limited due to its low protein content, making it less suitable for poultry feed. To increase the benefit values of the sago pith, it is necessary to process it through fermentation. The current study aimed to determine the effects of substrate composition and fermentation time of fermented sago (Metroxylon sagu) pith (SP) and Indigofera (Indigofera zollingeriana) leaves (IL) mixture using Rhizopus oligosporus as an inoculum on crude protein, crude fat and crude fiber content of fermented SP and IL, nitrogen retention, crude fiber digestibility, and energy metabolism in broiler chickens. The study was performed on 30 broiler chickens, average weighing ± 1.5 kg at 6 weeks of age, along with SP, IL, and R. oligosporus. This experiment was conducted using a randomized design in a 3x3 factorial with three replications. Substrate composition, or factor A, was made up of A1 (80 SP + 20 IL), A2 (60 SP + 40 IL), and A3 (50 SP + 50 IL). Fermentation time as Factor B entailed B1 (2 days), B2 (3 days), and B3 (4 days). The findings demonstrated a significant interaction between the time of fermentation and the composition of the substrate in relation to crude protein content, nitrogen retention, crude fat, crude fiber digestibility, and energy metabolism. It can be concluded that the composition of substrate 50 SP and 50 IL with 3 days of fermentation yielded the best result, with crude protein at 25.45, nitrogen retention at 59.72, crude fat at 0.020, crude fiber at 6.40, crude fiber digestibility at 57.34, and metabolic energy at 2658.44 kcal/kg. © The Author(s) 2023. All Rights Reserved.