Effects of Corn Naturally Contaminated with Aflatoxins on Performance, Calcium and Phosphorus Metabolism, and Bone Mineralization of Broiler Chicks

抄録

The objective of this study was to investigate the effects of corn naturally contaminated with low levels of aflatoxins (AF) on performance, calcium (Ca) and phosphorus (P) metabolism, and bone mineralization in broilers. Four hundred and fifty 1-d-old male broiler chicks were randomly allotted to control (no AF), and the diet with the corn contaminated with AF as a substitute for 50% or 100% of the corn in control (HAC or AAC). The broilers in HAC and AAC were administered with 6.5-8.0 and 13.0-16.0 μg AF/kg BW per day respectively in overall period (1-42 d). Ten birds per treatment were selected at d 43 to explore the apparent digestibility of Ca and P using all excreta collection method after 2 days adaptation. The AAC diet reduced (P<0.05) the performance of birds in overall period, whereas the HAC diet temporarily decreased (P<0.05) the performance of birds in starter phase (1-21 d). The corn contaminated with AF had no effect (P>0.24) on the apparent digestibility of Ca and P. The increasing AF intake content linearly increased (P<0.001) serum parathyroid hormone (PTH) level, and decreased (P<0.05) serum 1,25-dihydroxychocalciferol and P concentrations on d 42. On d 21, the AAC diet reduced (P<0.05) tibia breaking strength (TBS) when compared to control or HAC group, however, it did not affect (P>0.10) the percentages of ash, Ca and P in tibia. On d 42, the increasing AF intake level linearly decreased (P<0.05) TBS, and the percentages of Ca and P in tibia. These results indicated that the low level of AF intake had negative effects on the P metabolism and bone mineralization of broilers at exposure of 42 days, which might relate to the changes in vitamin D and PTH metabolism.