Dietary high -tannin sorghum and oxidative stability of muscle and muscle foods

The main hypothesis of this work was that feeding animals with high-tannin sorghum (HTS) would produce muscle tissue more resistant to oxidative deterioration, reducing the rates of discoloration and lipid oxidation during aerobic display of the muscle tissue.;In rats fed HTS we observed a reduction in protein oxidation in muscle after six days of aerobic storage, while in steers fed HTS we observed an accelerated rate of discoloration and lipid oxidation during aerobic display of beef. Furthermore, in steers we observed lower markers of lipid oxidation in Gluteus medius muscle from animals fed the HTS diet. Thus, dietary HTS appears to be modulating lipid oxidation in beef by at least two different mechanisms: first, one that reduced oxidation before aerobic storage, and second, one that accelerates oxidation during aerobic display of the tissue. Less lipid oxidation before aerobic display could be explained by a muted response to stress in steers fed HTS, while the accelerated rate of lipid oxidation during display could be at least in part explained by a numerically lower concentration of tocopherols in the tissue.;In consequence, we rejected the null hypothesis that feeding animals with HTS would have no effect in the oxidative stability of the muscle. Our alternative hypothesis was that feeding animals with HTS would produce muscle tissue more resistant to oxidative deterioration. Our results support the alternative hypothesis only in muscle tissue from rats, while in muscle tissue from steers we observed the opposite effects with HTS diets increasing the rates of discoloration and lipid oxidation during beef display.;The secondary hypothesis of this work was that partial replacement of corn by HTS in the diets would not have a detrimental effect in the growth of animals. We gathered evidence to reject the null hypothesis that partial replacement of corn by high-tannin sorghum would reduce the growth rate of animals. Up to 50% of diet dry matter as HTS did not reduce weight gain of young and adult rats, while up to 38% of diet dry matter as HTS did not reduce weight gain in finishing steers.