Proximate Composition And Mineral Content Of Fish Species Fillets In Relation To The Fish Size: In The Case Of Koka Reservoir, Ethiopia

Abstract

Fish is essential for food security and nutrition. The nutritional quality of the fish is affected by age, sex, food availability, environment, and season. The estimation of these contents aids in ensuring their dietary needs and commercial specifications. The current study aimed to estimate the proximate composition and mineral content of four fish species in the Koka reservoir. Fish samples were randomly collected from Koka reservoir at landing sites, kept in an icebox at 4oC and immediately transported to the Ambo University Biology Department Laboratory. Prior to determining the proximate and mineral composition, the fillet parts of the fish were immediately taken and stored in the refrigerator. An experimental correlational design that involved the quantitative data collection approach was used in this study. The proximate composition and mineral contents of the samples were determined following the standard procedures of the Association of Official Analytical Chemists. C. carpio and L. intermedius had the highest mean moisture (80.79±2.44%) and protein (17.38±1.61 mg/100g) contents, but C. gariepinus had the highest crude fat content (0.84±0.31g/100g) and ash contents (3.06±0.60 g/100g). In other words, there was no significant difference in moisture content among the three size groups of all fishes (p>0.05), except for C. carpio (p<0.05), but protein and carbohydrate content did (p<0.05). The fat content of all fishes varied between sizes (p<0.05), except for C. carpio (p>0.05), but only O. niloticus and C. carpio showed a significant difference in ash contents (p<0.05), all mineral contents varied significantly among the fish species (p<0.05) except for copper (p>0.05) C. carpio had the highest mean calcium (103.33 mg/100g) and magnesium (412.67 mg/100g) contents, but the mean iron (256.83 mg/100g), zinc (15.5mg/100g), manganese (3.8 mg/kg), and copper (3.26mg/100g) were found to be highest in O. niloticus. Except for Cu, the results revealed a significant difference in mineral content among fish species (p<0.05). All mineral contents differed significantly between the different size groups of O. niloticus and C. carpio (p<0.05). In general, the proximate and mineral contents recorded in the fish species are moderate and promising enough to support people's nutritional security. Therefore, it is pivotal to cultivate these fish species to improve their nutritional quality and further contribute to food security.