## 4 Discussion  
Many studies have shown that Mo levels less than 3 or 2 ug/g (DM) in forage and soil samples, respectively, are very safe for ruminants [25]. In our study, Mo levels were much higher (\(p<0.01\)) than those in the healthy pasture. At the same time, an increase of Mo content in forage will affect the absorption of Cu by animals. The Cu contents in hair and blood in affected gazelles were lower (\(p<0.01\)) than those in unaffected gazelles, while Mo levels were higher (\(p<0.01\)) than those in healthy gazelles. This leads to secondary Cu deprivation caused by body absorption disorder [26; 27; 28]. The Cu contents in affected gazelles were 0.17 ug/g, but the average blood Cu values of <0.50 ug/g are a sign of severe Cu deficiency for ruminants [6]. The Cu concentration in hair is also a common index to evaluate mineral nutrition status of animals [29; 30]. The mean level of Cu in hair sample in affected gazelles of 3.99 \(\pm\) 0.33 ug/g was also well below the 5.5 ug/g level of secondary Cu deprivation [6; 9]. In addition, the Cu concentrations in hair and blood of affected gazelles reached the normal level after oral administration of CuSO\({}_{4}\) until the 10 th day. Thus, it was reasonable to conclude that the ailment in gazelles in the Qinghai Lake watershed might be Cu deprivation caused by the high Mo content in forage. Many studies in animals and humans have shown that there is a significant correlation between Cu deprivation and anemia [31; 32]. In this study, the blood routine parameters showed that the values of RBC, Hb and PCV in Cu-deprived gazelles were very decreased, indicating that Cu deprivation had different effects on blood cells of gazelles. The levels of AST, ALT and ALP in blood were commonly used as indices to evaluate animal liver health, and the activities of LDH and CPK in blood were commonly used as indices to reflect the degree of muscle and kidney injuries. The content of ALB changed with the change of feed protein. The content of ALB decreasing indicated that there was a lack of protein, and it might also be the decrease of ALB synthesis caused by liver diseases. GLB was synthesized by the immune organs of animals, most of which were produced outside the liver cells, but also related to the immune system of the organism [33; 34]. The concentrations of ALB and GLB complement each other to maintain a constant level of total protein [35]. The activities \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Elements**} & \multicolumn{3}{c}{**Treatment Group**} & \multicolumn{3}{c}{**Control Group**} \\ \cline{2-7}  & **0 d** & **10 d** & **20 d** & **0 d** & **10 d** & **20 d** \\ \hline Cu & 0.17 \(\pm\) 0.04 * & 1.53 \(\pm\) 0.17 * & 1.77 \(\pm\) 0.16 * & 0.17 \(\pm\) 0.03 & 0.16 \(\pm\) 0.03 & 0.14 \(\pm\) 0.04 \\ Mo & 0.22 \(\pm\) 0.02 & 0.19 \(\pm\) 0.02 & 0.17 \(\pm\) 0.01 & 0.24 \(\pm\) 0.03 & 0.22 \(\pm\) 0.04 & 0.21 \(\pm\) 0.03 \\ Fe & 441.43 \(\pm\) 61.87 & 443.75 \(\pm\) 62.38 & 442.86 \(\pm\) 59.32 & 441.65 \(\pm\) 60.65 & 439.68 \(\pm\) 63.48 & 439.65 \(\pm\) 67.86 \\ Mn & 0.53 \(\pm\) 0.02 & 0.52 \(\pm\) 0.01 & 0.52 \(\pm\) 0.02 & 0.54 \(\pm\) 0.03 & 0.53 \(\pm\) 0.02 & 0.51 \(\pm\) 0.02 \\ Co & 0.54 \(\pm\) 0.04 & 0.54 \(\pm\) 0.04 & 0.56 \(\pm\) 0.02 & 0.55 \(\pm\) 0.04 & 0.57 \(\pm\) 0.03 & 0.56 \(\pm\) 0.03 \\ \hline \hline \end{tabular}
* Indicates great difference at \(p<0.01\).  
\end{table} 
Table 6: The mineral element level in animal blood (ug/g). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Items** & **Affected Gazelles** & **Healthy Gazelles** \\ \hline T-AOC (U/mL) & 2.23 \(\pm\) 0.11 * & 4.75 \(\pm\) 0.21 \\ GSH-Px (U/mL) & 227.54 \(\pm\) 11.77 * & 351.65 \(\pm\) 17.36 \\ MDA (mmol/L) & 42.48 \(\pm\) 4.27 * & 13.76 \(\pm\) 2.26 \\ SOD (U/mL) & 58.37 \(\pm\) 4.52 * & 99.72 \(\pm\) 9.96 \\ CAT (U/mL) & 6.76 \(\pm\) 0.21 * & 14.36 \(\pm\) 1.76 \\ \hline \hline \end{tabular}
* Indicates great difference at \(p<0.01\).  
\end{table} 
Table 5: The antioxidant levels in serum in gazelles.