The efficacy of a standardised product from dried leaves of Solanum glaucophyllum as source of 1,25-dihydroxycholecalciferol for poultry

1. Chemical characterisation of an extract of Solanum glaucophyllum (SG) leaves affirmed the predominant presence of 1,25-dihydroxycholecalciferol (1,25(OH)(2)D-3) glycosides. The compound 1-(ss-D-glucopyranosyl)-1,25-dihydroxycholecalciferol was isolated for the first time from a natural source.2. Vitamin D activity of the extract was confirmed by the calcaemic properties shown in a quail eggshell bioassay. The results suggested a 1,25(OH)(2)D-3 bioavailability of approximately 15%.3. A broiler feeding experiment replicated in time was carried out with 6 treatments. A basic control diet containing 25 g cholecalciferol/kg was supplemented with 2.5 and 5 g free 1,25(OH)(2)D-3/kg, with a product based on dried SG leaves (Panbonis) providing 10 g of 1,25(OH)(2)D-3-glycosides/kg, with two concentrations of an SG extract providing 8.8 and 37.8 g of 1,25(OH)(2)D-3-glycosides/kg.4. Tibia breaking strength and stiffness were numerically greater in all treatment groups with free 1,25(OH)(2)D-3 and with SG products compared to controls, though the overall treatment effects only had probabilities in the range of P=0.07 to P=0.1. Values for both characteristics increased progressively, with additions of synthetic 1,25(OH)(2)D-3; values with the dried SG product were similar to those with 5 g synthetic 1,25(OH)(2)D-3/kg.5. Plasma calcium was mildly elevated (P