Nutritional Comparison of Transgenic and Local Cowpea Grown in Nigeria

Abstract

Cowpea, a common nutritious legume in Nigeria, faces significant productivity challenges from the pod-boring pest, Maruca vitrata. This study investigated the nutritional differences between genetically modified varieties expressing Cry1Ab (a recombinant insecticidal toxin) and local cowpea varieties. Four cowpea varieties, including a transgenic variety (Sampea-20T), its non-transgenic counterpart (Sampea-10), and two improved varieties (Iron Beans and Ife Brown), commonly found in Nigerian markets, were evaluated for proximate, mineral and amino acid profiles using standard techniques. Sampea-20T and Sampea-10 were substantially similar in terms of crude protein, crude fiber, and crude fat, with slight differences in ash and carbohydrate content. Sampea-20T significantly differed from Ife brown and iron beans cowpea varieties in multiple nutritional components. Ife brown had a significant mineral profile, while Sampea-20T and Sampea-10 were similar except for potassium (K) and magnesium (Mg). Sampea-20T had notably higher levels of histidine, isoleucine, and leucine compared to the other varieties but lower levels of tryptophan. Sampea-20T had considerably higher levels of five out of nine non-essential amino acids compared to Sampea-10, along with comparable quantities to Ife brown and iron beans in four amino acids. This study has shown that there were no biologically significant differences (p<0.05) found among the compositional parameters measured in cowpea samples taken from the transgenic cowpea (Sampea-20T), its non-transgenic counterpart (Sampea-10), and local commercial varieties (Ife brown and Iron beans).