**7.2 Toxicological studies**

All toxicity assessment for GM material should be performed based on a case-bycase approach, considering the toxicological profile of new introduced substances [35]. The purpose of toxicological studies is to characterize intended changes and detect active substances or compounds that could have unexpected toxic effects for non-targeted organisms [36]. The assessment of toxicity analysis in animal new strategies have been identify for GM feed and foods. Research on the in-planta metabolism pathway, such as "-omics" techniques that may generate a better understanding of the complex pleotropic effects of new plant cultivars [37]. Additionally, *in vitro* assays with gastric enzymes, cultured cell lines, receptor proteins, and *in vivo* animal studies can be performed [36]. When performing *in vivo* studies, toxicology acute (14 days studies), subacute (28 days studies), chronic (90 days studies), or specific toxicity (reproductive, mutagenicity, etc.) assessment can be considered [38]. In long term studies (>100 days), no toxic effects were found in cattle and chickens fed with Bt maize. The toxicological evaluation of proteins introduced into GM crops must be carried out for introduced or release of GMO crops and carefully assess the modification of amino acid sequences that make a non-toxic protein to toxic protein [39].
