Comparative Studies on the Free Amino Acid Composition in the Total Body Homogenate of some Lepidopterous and Neuropterous Insects دراسة لمقارنة محتوى الأحماض الأمینیة لبعض حشرات رتبتی حرشفیة وشبکیة الأجنحة

Abstract

Three different insect species belonging to three families [i.e. P. gossypiella (PBW), S. littoralis (CLW) and C. carnea (APL)] were studied for their amino acid composition. Seventeen free amino acids (FAA) figured out in the total body homogenate of the tested insects. The essential AA were threonine (THR), valine (VAL), methionine (MET), isoleucine (ILE), leucine (LEU), phenylalanine (PHE), lysine (LYS). Semi-essential AA were histidine (HIS), arginine (ARG), cysteine (CYS), and Non-essential were aspartic acid (ASP), serine (SER), glutamic acid (GLU), glycine (GLY), alanine (ALA), tyrosine (TYR), and proline (PRO). Generally, results showed that non-essential AA were the most predominant fraction of FAA, following by essential then semi-essential AA, and the PBW had the highest average of AA (1.89, 1.32 & 2.41 for essential, semi-essential & non-essential AA, respectively), followed by APL (1.78, 1.22 & 2.34, respectively), then CLW (1.66, 1.16 & 2.17, respectively). In details, from the results it could be grouped AA in 3 groups as follows: 1-A high AA concentration (more than 3 mg/100mg). 2-A moderate AA concentration (more than 2 mg/100mg). 3-A low AA concentration (less than 2 mg/100mg).The results showed that the PBW characterized by a high AA concentration of ASP (3.19 mg/100mg) and GLU (4.24 mg/100mg), while CLW and APL had only a high AA concentration of GLU (3.98 & 5.24 mg/100mg, respectively), and a moderate concentration of ASP (2.46 & 2.90 mg/100mg, respectively). In addition, GLU had a highest concentration in APL. The obtained results indicated that glutamic acid and aspartic acid (non-essential AA) were the most predominant FAA. For moderate AA, PBW characterized by an amino acids VAL and TYR (2.28 mg/100mg; 17.26% & 2.53 mg/100mg; 13.88%, respectively). In contrast, CLW and APL had a low VAL and TYR concentration (1.73 & 1.78 mg/100mg; 14.91 & 14.25% & 1.63 & 1.87 mg/100mg; 9.96 & 10.61% for VAL & TYR, respectively). Also, ALA had a moderate concentration in PBW (2.28 mg/100mg) and CLW (2.50 mg/100mg), while had a low concentration in APL (1.83 mg/100mg). In addition, CYS had a least concentration of AA (0.55, 0.59 and 0.57 mg/100mg for PBW, CLW and APL, respectively.