Effects of three sources of chromium on growth traits, fermentation parameters, protozoa population and some blood metabolites in Mehraban male lambs

The aim of this study was to evaluate the effect of three sources of chromium (Nano-Cr, Met-Cr and Bonza-Cr) on growth performance, ruminal fermentation, some blood metabolites and rumen protozoan population in Mehraban fattening lambs. Twenty-eight lambs 7 month of age (mean body weight of 27.30 ± 3.98 kg), were randomly allocated to four dietary treatments for 63 days during winter season, -6 to 15 centigrade, using completely randomized design. The feed conversion ratio of Cr supplemented groups were not different from that of control group (P=0.11). The gas production, organic matter degradability and metabolizable energy in lambs receiving Met-Cr and Cr-Bonza on day 60 were higher than those of other groups (P˂0.001). The ammonia nitrogen decreased (P˂0.05) in lambs receiving Met-Cr and Bon-Cr compared to other groups on days 40 and 60 of experiment. Total volatile fatty acids of rumen liquor of lambs supplemented with Cr were increased (P=0.03) compare to control on day 40 of experiment. The protozoa count did not influence due to incorporation of Cr to diet (P>0.05). The serum albumin of lambs received Nano-Cr and blood urea concentration of Cr supplemented animals were affected (P<0.05). The overall results indicated that the addition of Met-Cr and Bonza-Cr increased the growth of lambs, but it did not affect the population of protozoa and gross profits.