ABSTRACT
This study conducted to evaluate the effect of zinc element, either in Large particles (LP-Zn) or Nano particles (NP-Zn)] forms, as a feed supplement in rations of Ossimi ewes on feed intake, digestibility, feeding value, milk yield and offspring performance. Fifteen ewes used before lambing. They averaged 39.37±0.64 kg live body weight and aged 3-4 years. Animal allotted randomly into three similar groups (5 animals each) to receive one of the experimental diets. The control ration (CR) consisted of concentrate feed mixture (CFM), Berseem hegazi hay (BHH) and rice straw (RS). The two tested groups fed the same control ration supplemented either with 10 mg large size particles of zinc (LP-Zn) or 5 mg nano particles of zinc (NP-Zn) per kg CFM, G2 and G3 respectively.
Results indicated that digestibility of most nutrients (DM, OM, CF and NFE) were significantly the highest with NP-Zn ration in comparison with other treatments. Similar trends observed with TDN and DCP values among treatments. Percentage of body weight changes during experimental period increased (P<0.05) by 4.96 and 12.54 % for ewes treated by LP-Zn and NP-Zn, respectively. In addition, the feed intake calculated as DMI, TDN and DCP were significantly higher with NP-Zn ration than other ones. Actual daily milk yield (ADMY) and 6% fat corrected milk yield (FCMY) were higher for both tested rations (LP-Zn & NP-Zn) than control, with superiority of NP-Zn ration. Data indicated that supplementation of diet with NP-Zn affected positively (P<0.01) the total antioxidant capacity (TAC), glutathione-S-transferase (GST) activity, prolactin, triiodothyronine (T3), and thyroxin (T4) concentrations at 15, 45 and 75 days post-lambing in comparison to control group for ewes and their lambs. Also, concentration of immunoglobulin (IgG) in serum samples of ewes and their lambs recorded the highest values with NP-Zn group. Serum total protein, albumin, globulin and glucose values in NP-Zn group recorded the highest values, followed by LP-Zn group, while control group had the lowest, either for ewes or suckling lambs. Serum AST, ALT and urea measurements were within the normal range for healthy sheep.
It conclude that small amount of zinc in nano size, could replace zinc in normal size without any side effects on animal performance. In addition, zinc supplementation could improve nutrients digestibility, feed conversion, milk production and some related serum biochemical indicators.