Antagonistic effects of different selenium sources on growth inhibition, oxidative damage, and apoptosis induced by fluorine in broilers

Fluorosis can induce oxidative stress through leading to reactive oxygen species (ROS) generation. Selenium (Se) can eliminate ROS by direct and indirect manners. In this study, therefore, we investigated the possible protective effects of sodium selenite (SS) and selenomethionine (Se-Met) on fluorine (F)-induced oxidative stress in broilers. A total of 720 1-day-old Lingnan Yellow broilers were allotted to 4 groups (6 replicates of 30 birds each group) and fed with basal diet (control group), 800 mg/kg F (high F group), 800 mg/kg F+0.15 mg Se/kg as SS (SS group), or Se-Met (Se-Met group), respectively. The experiment lasted 50 d. High F group significantly decreased (P < 0.05) the average daily gain (ADG) and feed efficiency (FE) in comparison with control group. The contents of ROS, malondialdehyde, 8-hydroxydeoxyguanosine, protein carbonyl, and cysteinyl aspartate specific proteinases 3 in serum, liver, and kidney were higher (P < 0.05) in high F group than those in control group. Compared with control group, the decreased (P < 0.05) activities of glutathione peroxidase (GSH-Px) and cytoplasmic thioredoxin reductase (TrxR1) as well as contents of selenoprotein P (SelP), total protein (TP), and B-cell lymphoma-2 in serum and tissues were observed in high F group. Moreover, the pathological lesions of liver and kidney in high F group were more than those in control group. However, supplementation with SS and Se-Met could improve ADG and FE, increase SelP and TP concentrations, elevate GSH-Px and TrxR1 activities, minimize the changes of oxidative stress and apoptosis parameters as well as ultrastructure of liver and kidney, whereas the effects of Se-Met were better than those of SS. The results indicated that excess F could result in growth inhibition of broilers through inducing oxidative stress and subsequently caused oxidative damage to biological macromolecules and soft tissues as well as apoptosis, whereas dietary SS and Se-Met supplementation could antagonize high F induced growth retardation by inhibiting oxidative stress and a mechanism of apoptosis regulation and the impact was more with Se-Met.