PSX-29 Application of substandard jujube meal in pig diets: Energy value and nutrient availability.

Abstract Substandard jujube (Ziziphus jujuba Mill.) fruits—cracked, undersized, or mechanically/insect damaged—account for 20% to 35% of global production yet retain high levels of sugars, polysaccharides, phenolics, and flavonoids. Converting these abundant by-products into jujube meals offers a sustainable, value-added alternative to traditional cereals, such as corn, reducing feed costs and environmental waste while delivering bioactive compounds. However, baseline data on its nutritive value in swine are lacking. This study therefore aimed to (1) establish the digestible energy (DE), metabolizable energy (ME), and apparent nutrient digestibility of high-quality and substandard jujube meals in pigs, and (2) apply these values to formulate diets containing graded levels of substandard jujube meal to assess effects on energy utilization and apparent nutrient digestibility. Two sequential metabolism trials were performed using Duroc × Landrace × Yorkshire barrows in individual crates. In Exp. 1, eight pigs (50.04 ± 0.76 kg) were used in a 4 × 4 Latin-square design (7 d adaptation + 7 d total collection). About 50% of the corn in a basal diet was replaced by high-quality jujube (HJ) or one of three substandard grades (SJ1, SJ2, SJ3) collected from different regions to determine DE, ME, and apparent nutrient digestibility of crude protein (CP), ether extract (EE), neutral-detergent fiber (NDF), acid-detergent fiber (ADF), calcium, and phosphorus. In Exp. 2, ME and nutrient digestibility values from Exp. 1 guided the formulation of four growing diets containing 0% (JP0), 5% (JP5), 10% (JP10), or 15% (JP15) substandard jujube meal. Sixteen pigs (57.40 ± 0.60 kg) were provided with grower diets. Each diet was fed for 14 d (7 d of adaptation + 7 d of collection) to measure DE, ME, and apparent nutrient digestibility. The data were analyzed using SAS 9.4 (Cary, NC, USA) with a one-way ANOVA test. Results showed that HJ provided higher (P < 0.05) DE (13.76 MJ/kg) and ME (13.22 MJ/kg) than SJ1 (11.57 MJ/kg, 11.13 MJ/kg), SJ2 (10.96 MJ/kg, 10.42 MJ/kg), and SJ3 (10.58 MJ/kg, 10.20 MJ/kg). The DE/GE and ME/GE ratios were greater (P < 0.05) for HJ (83.2%, 80.0%) than for SJ1, SJ2, and SJ3 (68.6 - 71.3%, 66.1 - 68.6%), and ME/DE did not differ (95 - 96%). In Exp. 2, inclusion of up to 15% of substandard jujube powder did not affect DE, ME, apparent digestibility, or nitrogen retention relative to JP0. In conclusion, this work provides the first comprehensive dataset on the nutritive value of jujube meals for pigs. It demonstrates that substandard jujube can replace up to 15% of corn in finishing diets without compromising energy utilization or nutrient digestibility, thereby enabling the formulation of jujube-based feed and supporting future research on functional benefits in swine production.