Effects of ascorbic acid and lighting schedule on tibiotarsus strength and bone characteristics in broilers

Abstract. This study was conducted to determine the effects of two lighting programs (continuous program; 24 h lighting or intermittent; 12 h daylight followed by three cycles of 1 h lighting and 3 h dark program during the night period) and three different ascorbic acid (AA) supplementations (0, 200 and 400 mg/l, added to water) on some serum parameters, ash content and mechanical properties of tibiotarsus. For this purpose one-day-old male commercial (Ross PM₃) broiler chicks (n=600) were divided into 6 treatment groups (2×3) with random replicates (4 replicates per treatment). At the end of 6 weeks, intermittent lighting program negatively influenced serum alkaline phosphatase (ALP) and calcium (Ca) levels (P<0.001) while continuous lighting program had positive influence on bone ash, Ca and phosphorus (P) content (P<0.001). The AA addition decreased serum inorganic phosphorus (Pi) level and positively affected bone chemical characteristics (P<0.001). On the mid-section of the bone, although intermittent lighting had positive effect on bone mechanical parameters (P<0.001), no remarkable effect was observed by AA supplementation. The results of the present study suggest that interaction of intermittent lighting and AA supplementation (200 mg/ l) may have positive effect on chemical composition and mechanical characteristics of bone in broilers.