1,25-dihydroxycholecalciferol from Solanum glaucophyllum supports normal growth and reduces the negative effects of calcium and phosphorus restriction on broilers’ bone tissue

Abstract

Feed supplementation with 1,25-dihydroxycholecalciferol (1,25(OH)2D3) has been studied as a means to decrease the incidence of bone abnormalities in broilers and reduce dietary inclusion of calcium and phosphorus. The objective of this research was to determine the optimal level of feed supplementation with 1,25(OH)2D3 from Solanum glaucophyllum for growing broilers restricted in calcium and available phosphorus. A total of 648 day-old male chicks were distributed in a completely randomized design with six dietary treatments and six replications of 18 birds. Treatments consisted of one positive control (PC: corn-soybean-meal diet formulated to reach or exceed Rostagno et al. (2011) nutritional recommendations), one negative control (NC: PC diet with 15% reduction of calcium and available phosphorus), and four NC diets supplemented with 0.5, 1.0, 1.5, or 2.0 µg kg-1 of 1,25(OH)2D3. Performance and bone development characteristics were evaluated at days 21 and 33. Negative control did not modify broilers’ performance in comparison with PC, but birds fed with NC plus 1.0 µg kg-1 of 1,25(OH)2D3 showed higher (p = 0.01) daily weight gain than PC at day 21. Negative control reduced (p < 0.01) tibia weight, ash, breaking strength, and Seedor index at day 21, but supplementation with 1,25(OH)2D3 mitigated all these negative effects. A quadratic effect of 1,25(OH)2D3 level was found for daily weight gain (p = 0.03), tibia weight (p < 0.01), breaking strength (p < 0.01), and Seedor index (p < 0.01) at this age. At day 33, NC broilers still had lower tibia weight (p = 0.01), ash (p < 0.01), and Seedor index (p < 0.01) than those fed PC. Only tibia ash did not return to the same value as that observed in PC after NC supplementation with 1,25(OH)2D3. A quadratic effect (p < 0.01) of 1,25(OH)2D3 level was found for tibia ash and Seedor index at this age. On average, dietary supplementation of 1.15 µg kg-1 of 1,25(OH)2D3 was identified as the optimal level for bone characteristics in this trial. For performance, this level was 0.98 µg kg-1. In conclusion, feed supplementation with 1,25(OH)2D3 from standardized leaves of Solanum glaucophyllum sustains normal growth and reduces the negative effects of calcium and phosphorus restriction on broilers’ bone tissue.