Effects of Long-Term Mineral Block Supplementation on Antioxidants, Immunity, and Health of Tibetan Sheep

Tibetan sheep have been observed with mineral deficiencies and marginal deficiencies in Qinghai-Tibetan Plateau. Adequate amounts of essential minerals are critical to maximize the productivity and health of livestock. The objectives of this study were to evaluate the effects of 6 months of mineral block supplementation on the antioxidants, immunity, and health of Tibetan sheep. The study was conducted in Qinghai-Tibetan Plateau. The consumed values of mineral blocks were measured. Blood samples were collected at the end of the experiment to evaluate the trace elements, malondialdehyde (MDA) and glutathione (GSH) activities, and antioxidant enzyme activities. Additionally, levels of IgA, IgG, IgM, IL-2, IL-12, tumor necrosis factor-alpha (TNF-alpha), triiodothyronine (T3), tyroxine (T4), and insulin-like growth factor-1 (IGF-1) were determined. The toxic effects of the mineral block were also monitored. For Tibetan sheep, the average consumed value of mineral block was 13.09 g per day per sheep. Mineral block supplementation significantly increased the serum levels of Mn, Fe, and Se (P < 0.01), decreased the level of MDA (P < 0.05), and increased GSH activity (P < 0.05). Additionally, the mineral block-treated sheep blood had greater total antioxidative capacity (T-AOC) and total superoxide dismutase (T-SOD) activities (P < 0.01 or P < 0.05) than control sheep. Moreover, the mineral block supplementation improved the levels IgA, IgM, and IGF-1 (P < 0.01 or P< 0.05). Additionally, there were no significant histopathological changes in the organs of Tibetan sheep after long-term treatment with the mineral block. The results demonstrated that the mineral block was non-toxic and safe; the protective effects of the mineral block might be caused by an increase in the antioxidant defense system, as well as an increase in the benefits from immunity-related parameters.