The invention provides a mineral complex comprising about 40 wt. % to about 60 wt. % SiO2, about 6 wt. % to about 16 wt. % Fe2O3, about 4 wt. % to about 12 wt. %. CaO, and about 2 wt. % to about 8 wt. % MgO. The invention also provides animal feeds comprising the mineral complex. Methods for increasing the feed efficiency and weight gain in an animal by administering the mineral complex or an animal feed comprising the mineral complex also are provided.