Transcriptome Analysis Identifies Signaling Pathways Related to Performance, Meat Quality, and Organ Development in Multienzyme-Supplemented Kampung Unggul Balitbangtan (KUB) Chickens.

Kampung Unggul Balitbangtan (KUB) chicken is a superior Indonesian native breed with high adaptability, good growth potential, and desirable meat quality. Nutritional strategies such as multienzyme supplementation are increasingly applied to improve productivity and meat quality without altering basal diet composition. This study investigated the effects of dietary multienzyme supplementation, consisting of phytase and protease, on growth performance, carcass characteristics, organ development, meat quality, and muscle-related gene expression in KUB chickens. Sixteen one-day-old male KUB chicks were randomly allocated to four dietary treatments: a control diet without multienzymes and three diets supplemented with phytase (200 mg/kg) combined with protease at 300, 500, or 700 mg/kg of feed. Growth performance parameters were measured up to 45 days of age, followed by carcass evaluation, organ weight analysis, meat quality assessment, and transcriptomic and quantitative real-time PCR analyses of breast muscle tissue. Multienzyme supplementation significantly improved final body weight and feed conversion ratio, particularly during the finisher phase, while reducing feed intake at higher enzyme inclusion levels. Carcass percentage and breast weight were enhanced in multienzyme-treated groups, accompanied by favorable changes in digestive and immune organ development. Meat quality analysis showed increased water-holding capacity, reduced cooking loss, and improved color characteristics, notably higher redness and lower yellowness values. Transcriptomic profiling and gene expression analysis revealed significant modulation of key muscle growth-related genes, including ACTA1, MYBPC1, TGFβ2, IGF2, and MYH9, indicating adaptive transcriptional responses associated with improved nutrient utilization rather than direct structural muscle alterations. In conclusion, dietary supplementation with a combination of phytase and protease effectively enhances growth performance, feed efficiency, carcass traits, and meat quality in KUB chickens while modulating growth-related gene expression. Multienzyme inclusion represents a promising and cost-effective nutritional strategy for improving productivity and meat quality in native chicken production systems.