Meta-analysis of organic chromium dietary supplementation on growth performance, carcass traits, and serum metabolites of lambs

There are inconsistent results on the effects of organic chromium (OCr) dietary supplementation on productivity, carcass traits, and blood metabolites of sheep. Therefore, this study aimed to evaluate the effects of OCr dietary supplementation on growth performance, carcass traits, meat composition, and serum metabolites of lambs using a meta-analytical approach. The final database included 16 studies from which the variables of interest were obtained. Data were analyzed using a random effects model, and results are presented as weighted mean differences (WMD) between OCr-supplemented and non-OCr treatments. OCr dietary supplementation did not affect dry matter intake; however, average daily gain increased, and feed conversion ratio decreased in response to OCr dietary supplementation. Dietary supplementation with OCr increased hot carcass weight, hot carcass yield, cold carcass weight, and Longissimus dorsi muscle area but decreased backfat thickness. In meat, OCr supplementation increased Warner-Bratzler shear force and protein content and decreased intramuscular fat content. In the blood, OCr dietary supplementation increased the serum concentration of insulin and triiodothyronine. However, serum concentrations of glucose, cholesterol, triglycerides, and thyroxine decreased in response to OCr dietary supplementation. In conclusion, organic chromium can be used as a dietary additive to improve average daily gain and feed conversion ratio in lambs and, at the same time, improve carcass traits, meat chemical composition, and serum metabolites.