Potential use of chromium to combat thermal stress in animals: A review

International audienceHeat stress (HS) has adverse effects on the body: it decreases body weight, feed efficiency, feed intake, carcassquality, and nutrient digestibility. Chromium (Cr) can prevent lipid peroxidation induced by HS through itsstrong antioxidant activities, especially when it is added to the poultry diet. It improves the action of insulinand nutrient metabolism (of lipids, proteins, nucleic acid, and carbohydrates) through activation of enzymes associated with such pathways. The results of the studies on Cr added to diets with concentrations of 0.05 mg Cr/kgof Cr-methionine led to improved feed efficiency and DM intake by cows and Holstein dairy calves exposed tohigh environmental temperatures. Moreover, calves that received Cr at levels of 0.05 mg/kg of body weighttended to have higher serum concentrations of glucose and higher ratios of insulin to glucose. In heat-stressedpigs, Cr addition (200 ppb) increased blood neutrophils by about 37%. Several studies have asserted that Cr caninhibit inflammation in lactating cows by promoting the release of Hsp72, assisting production of IL-10 andinhibiting degradation of IκBα in HS conditions. In addition, Cr supplementation was observed to possibly havepositive impacts on both cell-mediated and humeral immunity in heat-stressed buffalo calves. Studies over thelast two decades have shown with certainty that chromium supplementation has an impact on many variablesin chickens. Moreover, Cr is believed to increase insulin action in insulin-sensitive tissues (i.e., adipose and muscles), resulting in increased farm animal productivity through the improvement of feed intake, growth rate, carcass quality, reproductive parameters and immune functions