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.