The Effect of Organic Chromium Supplement on Growth Performance, Nutrients Digestibility and Some Ruminal Fermentation parameters and Blood Metabolites in Fattening Lambs

In the present study, fifteen Kermani male lambs with average body weight of 31.9±1.2 kg were used in a completely randomized design with 3 treatments and 5 replicates each, for 10 weeks including 2 weeks of adaptation to basal diet and 8 weeks of data collection. The experimental groups were (1) control group (without chromium-methionine (Cr-Met) supplementation), (2) lambs fed with 1.5 mg Cr/kg diet of Cr-Met, and (3) lambs received 3 mg Cr/kg of Cr-Met supplement. The results showed that average daily feed intake of lambs received 1.5 (p=0.002) and 3 (p =0.0004) mg/kg of Cr supplement was higher than that of the control animals. Chromium supplement had no influence on final body weight and average daily gain, however, feed conversion ratio decreased in lambs fed with 3 mg/kg diet of Cr supplement (p=0.04). The digestibility coefficients of dry matter, organic matter, fat and neutral detergent fibre (NDF) were not affected by the experimental treatments; however, acid detergent fibre (ADF) digestibility was higher in lambs fed with 1.5 (p=0.003) and 3 (p=0.02) mg Cr/kg of diet than those fed the control diet. Chromium supplement had no significant effects on pH and ammonia nitrogen (NH3-N) concentration of ruminal fluid. Similarly, serum glucose, total protein, albumin, globulin, triglyceride and urea concentrations were not different among experimental groups. It can be concluded that feeding 3 mg/kg diet of Cr-Met supplement improves feed conversion efficiency of fattening lambs. Moreover, both Cr-Met levels decrease feed intake and increase ADF digestibility.