70 Effect of Diamond V NaturSafe on receiving period cattle performance and markers of oxidative stress relative to transit.

摘要

Bawling beef steers (n=48; 257 ± 18 kg) were used to determine the effect of Diamond V NaturSafe® ( ) on performance and oxidative stress post-transit. Seven days after arrival (d-19; start of preconditioning; ) steers were weighed, stratified by BW, sorted into pens (n=1 pen/treatment; 12 steers/pen) and pens assigned to treatments: NS at 0 g·steer ·day ( ), 12 g·steer ·day ( ), 18 g·steer ·day ( ), or 0 g·steer ·day during PRE, then 18 g·steer ·day during receiving ( ; ). On d -1, steers were weighed then transported 1,748 km over 19-h. On d 0 (start of REC) steers were weighed, stratified by BW and sorted into pens with bunks that measured individual intake (experimental unit=steer; n=12 steers/treatment). Blood was collected on d -1, 1, and 8 for determination of red blood cell lysate superoxide dismutase ( ) activity. Liver biopsies collected on d -20 and -3 were analyzed for glutathione concentrations. Data were analyzed as a completely randomized design using ProcMixed of SAS with the fixed effect of treatment and the random effect of steer. Contrast statements compared dose or timing of treatments. Blood variables were analyzed as repeated measures. Transit resulted in 7% shrink. Steers fed NS12 had greater REC ADG and G:F from d 0 to 30 vs. NS18-fed steers ( ≤0.05). Total and Cu/Zn-SOD activity were lowest on d 1, greatest on d 8, and intermediate on d -1 ( ≤0.01). Manganese-SOD activity was lowest on d -1 and greatest on d 1 and 8 ( ≤0.01). Mn:Total-SOD activity was greatest on d 1 vs. d -1 and 8 ( ≤0.01). On d -3 NS12-fed steers had greater liver concentrations of total, oxidized, and reduced glutathione vs. NS18-fed steers ( ≤0.04). Supplementing NS at 12 g·steer ·day had positive implications on early receiving period performance and pre-transit antioxidant concentrations and could therefore be a beneficial addition to receiving cattle diets.