Effect of Nano-potassium Molybdate on the Copper Metabolism in Grazing the Pishan Red Sheep

The aims of this study were to investigate the impact of different levels of nano-potassium molybdate (nano-K2MoO4) fertilization on the copper (Cu) metabolism in grazing the Pishan red sheep in the natural pasture. The fertilization and grazing experiments were conducted on the Pishan farm in Southern Xinjiang, China. The natural pastures of 16 hm(2) were randomly divided into four groups (4 hm(2)/group), consisting of group C (no fertilized), group I, group II, and group III. The fertilizing amount of Mo from nano-K2MoO4 was 0, 7, 8, and 9 kg/hm(2) for group C, group I, group II, and group III, respectively. The 40 Pishan red sheep were randomly distributed to the tested pastures for 90 days, and the 10 sheep/group. The results showed that the contents of Mo and N in forage from the fertilized pastures were extremely increased (P < 0.01). The yield and dry matter digestibility of forage in fertilized pastures were significantly higher than those in no fertilized pasture (P < 0.01). The values of crude protein (CP) and crude fat (EE) in forage from fertilized pastures were significantly increased (P < 0.01). The Mo contents in the blood and liver in the Pishan red sheep from fertilized pastures were greatly increased (P < 0.01). The Cu contents in the blood and liver in the Pishan red sheep from the fertilized pastures were greatly decreased (P < 0.01). The activities of serum superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) in group I, group II, and group III were extremely lower than those in group C (P < 0.01), and the contents of serum malondialdehyde (MDA) in group I, group II, and group III were greatly higher than those from group C (P < 0.01). In summary, the application of nano-K2MoO4 improved the nutritive values and the yield of forage, but overuse will remarkably reduce the Cu contents of blood and greatly interfere with the Cu metabolism, leading to the Cu deficiency and low antioxidant capacity in grazing the ruminants.