**4.7 Combating metal toxicity**

Several researches have highlighted the problems of metal toxicity in poultry; which led to the establishment of nutritional guidelines on safety levels to protect both birds and humans from metal toxicity [54]. Nutritionally beneficial ones for good health but whose dietary excesses create health problems include iron, copper, manganese, zinc, etc.; whereas poisonous ones which may contaminate feeds from the environment include arsenic, mercury, lead, cadmium, vanadium, etc. [55, 56].
