The effect of zinc-methionine supplement on performance, nutrients digestibility and blood metabolites of fattening lambs

In order to investigate the effect of feeding zinc-methionine (Zn-Met) supplementation on growth performance, nutrients digestibility, ruminal fermentation parameters and some blood metabolites, an experiment was conducted on fifteen Kermani male lambs with average initial body weight of 32.1 ± 0.88 kg as a completely randomized design with 3 treatments and 5 replicates for 8 weeks. The experimental treatments were basal diet without supplemental Zn (Control), basal diet plus 50 mg Zn/kg diet of Zn-Met, and basal diet supplemented with 100 mg Zn/kg diet of Zn-Met. The results showed that lambs fed with 100 mg/kg diet of Zn supplementation had lower feed intake than the other treatments (P<0.01). Lambs received 50 mg Zn /kg of diet had higher average daily gain than those on control diet (P<0.05). Lambs fed with Zn supplementation (50 or 100 mg/kg) had better feed conversion ratio than the control group (P<0.05). The apparent digestibility of dry matter, organic matter and neutral detergent fiber (NDF) was higher in lambs fed 50 mg/kg of Zn supplementation than those of the control (P<0.05). However, no difference in fat and acid detergent fiber (ADF) digestibility was observed between treatments. Additionally, feeding Zn-Met supplementation diet had no significant effect on pH and ammonia nitrogen of ruminal fluidas well as serum glucose, total protein, triglyceride and urea concentrations of lambs. According to these results, feeding 50 mg/kg diet of Zn supplemented increases feed nutrients digestibility and compared with 100 mg of the supplement, has better effects on growth performance of fattening lambs.