Ziziphus spina‐christi (L.) Leaf Extract Improves Growth, Feed Utilization, Digestive Enzymes and Blood Metabolites in Broiler Chickens

Background Ziziphus spina‐christi has been a part of traditional medicine for centuries in North Africa and the Middle East. Numerous secondary metabolites have been isolated from this plant, such as alkaloids, flavonoids, polyphenols, vitamin C and bioactive polysaccharides. Therefore, using Z. spina‐christi leaf extract (ZSLE) is one of the recommendations for improving poultry performance and health. Objectives The goal of this study was to explore the influences of ZSLE as a feed additive on broiler growth, carcass traits, digestive enzymes, immunological and antioxidant parameters, lipid profile and blood metabolites. Methods A total of 250 one‐week‐old Arbor Acres broilers were distributed into 5 groups; each group contained 5 replicates with 10 birds each. The treatments were (1) basal diet (no additive, ZSLE‐0), (2) basal diet + 2 g ZSLE/kg (ZSLE‐2), (3) basal diet + 4 g ZSLE/kg (ZSLE‐4), (4) basal diet + 6 g ZSLE/kg (ZSLE‐6) and (5) basal diet + 8 g ZSLE/kg diet (ZSLE‐8). Results Z. spina‐christi reduced feed intake while improving body weight gain and feed conversion ratio (FCR) ( p < 0.05). During the 3–6 and 1–6 weeks, birds fed ZSLE‐4 improved FCR compared with the other birds ( p < 0.05). Compared to ZSLE‐0, ZSLE‐6 and ZSLE‐8 had substantially greater gizzard and giblet percentages. However, ZSLE had no effect on carcass, dressing, liver or heart percentages. Birds fed ZSLE‐4, ZSLE‐6 and ZSLE‐8 showed increases in amylase, lipase, protease, haemoglobin % (Hb), red blood cells (RBCs) and white blood cells (WBCs) count ( p < 0.05). ZSLE supplementation had no effect on aspartate aminotransferase (AST) ( p > 0.05), whereas ZSLE‐4 and ZSLE‐6 decreased alanine aminotransferase (ALT) levels ( p < 0.05). All ZSLE‐supplemented groups showed improvements in total protein, globulin and lipid profiles. ZSLE significantly decreased cholesterol, low‐density lipoprotein (LDL) and LDL/high‐density lipoprotein (HDL) ratio. HDL was increased in ZSLE‐4, ZSLE‐6 and ZSLE‐8 ( p < 0.05). Birds fed ZSLE‐6 and ZSLE‐8 improved the immunoglobulins (IgA, IgY and IgM), bursa of Fabricius%, thymus% and spleen% compared with the other birds ( p < 0.05). Additionally, lysozyme and C3 showed a significant linear influence. All ZSLE‐supplemented groups showed low blood glucose, creatinine, uric acid and malondialdehyde (MDA) ( p < 0.05). ZSLE improved antioxidant capacity, and ZSLE‐6 and ZSLE‐8 showed the highest reduced glutathione (GSH), catalase (CAT) and total antioxidant capacity (TAC) levels ( p < 0.05). Conclusion Collectively, ZSLE exhibits growth‐promoting, immunostimulant, antioxidant and hypolipidemic properties and can be employed as a natural extract in the diet of broiler chickens.