Selenium-methionine and chromium-methionine supplementation of sheep around parturition: impacts on dam and offspring performance

To examine the effects of maternal energy restriction along with selenium-methionine (Se-Met) and chromium-methionine (Cr-Met) supplementation on performance of pregnant sheep and their offspring, the following treatments were allotted randomly to 40 multiparous Baluchi ewes (53.9 +/- 1.15kg of body weight [BW]) from 5weeks prior to 5weeks after parturition: (1) Control diet (60% and 100% of NRC energy requirements in pre- and post-partum, respectively); (2) Control diet plus 5mg Se-Met/kg dry matter (DM); (3) Control diet plus 3mg Cr-Met/kg DM and (4) Control diet plus 5mg Se-Met and 3mg Cr-Met/kg DM (Se-Cr-Met) of concentrate diet. The results indicated that Cr-Met alone or in combination with Se-Met increased average DM intake of ewes. In addition, Group Cr-Met had higher average BW than the Control (p<0.05). Se-Met and/or Cr-Met supplementation led to decreased average serum cholesterol of the ewes (p<0.05). Groups Cr-Met and Se-Cr-Met displayed decreased average serum malondialdehyde compared to the Control (p<0.05). At 24h post-partum, Group Se-Cr-Met had a greater serum Se content than the Control (p=0.006). Compared with the Control, the Se concentration in milk was significantly increased from 30 to 138 mu g/l and 197 mu g/l in Groups Se-Met and Se-Cr-Met, respectively (p<0.01), which proved that Se-Met supplementation can increase the Se concentration of ewe milk. Furthermore, feeding Cr-Met may attenuate BW loss post-partum and Se-Met and/or Cr-Met supplements may ameliorate oxidative stress condition in ewes around parturition.