Influence of morphotypes and sex on the morphometry, meat yield traits, nutritional composition, fatty acid, and amino acid contents of Macrobrachium rosenbergii (De Man 1879)

Abstract

The present study examined the morphometrical characteristics, yield data, proximate composition, fatty acid, and amino acid profiles of the different male and female morphotypes of Macrobrachium rosenbergii. The prawn samples were collected from the grow-out ponds after a 120-day culture period, and they were segregated into four distinct groups such as small males (SM), orange claw males (OC), blue claw males (BC), and females (FE), following the standard identification methods. Out of 1000 specimens collected, the relative proportion study found a higher occurrence of small males (32.59 ± 2.18%) compared to other morphotypes and females. The morphometrical study revealed significantly higher body weight (66.59 ± 2.61 g) and dactyl length (4.33 ± 0.15 cm) in blue claw males. On the other side, the meat yield study revealed significantly higher cephalothorax weight (45.52 ± 1.81 g) and weight of the second leg (15.16 ± 1.08 g) in blue claw males, whereas tail weight percentage (49.89 ± 1.66% and 48.50 ± 0.48%) and somatic yield (96.02 ± 0.30% and 95.29 ± 0.38%) were found to be higher in females and small males, respectively. Proximate composition revealed higher levels of protein (22.23 ± 0.13% and 21.90 ± 0.25%) and lipid (5.77 ± 0.19% and 6.87 ± 0.19%) in small males and females, respectively. Upon analyzing the fatty acid profile, females had higher levels of omega-3 fatty acids (9.13 ± 0.05%), eicosapentaenoic acid (EPA) (7.84 ± 0.02%), omega-6 fatty acids (21.32 ± 0.05%), and PUFA/SFA ratio (0.72 ± 0.01). Interestingly, small males recorded higher levels of lignoceric acid (6.68 ± 0.02%). The essential amino acids, such as histidine (1.05 ± 0.03%), arginine (3.67 ± 0.10%), and methionine (0.53 ± 0.02%), were significantly higher in females. In contrast, the total amino acid level was found to be significantly higher in the small males (22.40 ± 0.65%). Overall, the findings of the present study recommend that females and small males have higher processing potential as they possess higher meat yield and better nutritional quality than other male morphotypes, which suggests that the processing industry could potentially use all morphotypes of males and females of M. rosenbergii for the sustainable expansion of the prawn farming industry.