The effect of dietary organic and inorganic selenium supplementation on serum Se, Cu, Fe and Zn status during the late pregnancy in Merghoz goats and their kids

The present study aims to determine the effect of dietary Se supplement on Merghoz goats at the last stage of gestation on serum Se, Cu, Zn and Fe status of goats and their kids. Thirty Merghoz does (30 ± 3 kg) were fed the same basal diet containing 0.11 mg Se kg−1 DM and randomly assigned to one of three dietary treatments in a randomized complete block design. Three weeks before the expected kidding, the basal diet was supplemented with 0 (control) or 0.3 mg Se head−1 d−1 in the form of l-selenomethionin (Se-Met) and 0.3 mg Se head−1 d−1 in the form of sodium selenite (SS). Blood samples were collected from the does three weeks before the expected kidding and on the kidding day. Blood samples of newborn kids were also taken from the jugular vein at birth and 7 days of age. The results indicated that the serum concentration of Se increased in supplemented does compared with the control ones. The selenium concentration was also significantly increased in colostrum of treated does (P < 0.05). There was no significant difference between Se sources on the Se status although there was higher efficiency of Se-Met than sodium selenite supplement. The serum concentration of copper increased in supplemented doses, which was concomitant with a reduction in Zn concentration in serum and colostrums. It seems that an increase in serum concentration of Cu at the end of pregnancy in goats given Se supplement could disturb the Zn:Cu ratios which in turn lead to Zn reduction. Serum Se, Cu and Fe concentrations of kids of treated doses increased at birth and first week of age, while the serum concentration of Zn decreased in newborn kids. It seemed that there was a positive correlation between serum Se concentration with Cu and Fe levels and also a negative correlation between Se and Zn in treated dose (P < 0.05).