Antioxidant Potentials of Blue Whiting Fish (Micromesistus poutassous) Oil Extracts in Streptozotocin Induced Diabetic Rats
Authors: Orji U. J. O. , Brown H. , Nwachuku E. O. , Boisa N. 
Published: July 2021

Aim: The aim of this study was to assess the antioxidant potentials of Blue Whiting Fish (Micromesistus poutassous) oil extracts in streptozotocin induced diabetic rats.

Study Design:  An experimental study.

Place and Duration of Study:  Animal House, Department of Applied and Environmental Biology, Rivers State University, Port Harcourt and University of Port Harcourt Rivers State, Nigeria, between February 2020 and August 2020.

Methodology: Thirty Six (36) albino rats were purchased and allowed to acclimatize for two (2) weeks in the laboratory at the animal farm house of the Department of Animal and Environmental Biology, Rivers State University. They were fed the normal rat feed (Chow feed) and water was allowed ad libitum.  The rats were weighed and randomly grouped into six (6) groups with six rats in each group. Group 1 (Negative control) was placed on normal diet while groups 2 to 6 were placed on a high fat diet (HFD) prior to the induction with Streptozotocin to achieve diabetes and the animals were treated according to their groupings for four weeks by means of oral gavage. The dose of Blue Whiting Fish (Micromesistus poutassous) oil extracts administered to the rats was extrapolated from human doses. The high fat diet was prepared by mixing the animal feed (Chow diet) with margarine in a ratio of 3:1. After each period of treatments, blood samples were collected from the rats at the end of the treatments via cardiac puncture by anaesthetizing the rats with chloroform after a six (6) hour fast. Fasting blood glucose was determined using the Glucose Oxidase method, total antioxidant capacity, malondialdehyde, superoxide dismutase and glutathione were analysed quantitatively and measured spectrophotometrically and the GC–MS analysis of bioactive compounds from Blue Whiting Fish (Micromesistus poutassous) oil was done using Agilent Technologies GC systems with GC-7890A/MS-5975C model. Data generated were analysed using SPSS version 22.0 of windows statistical package. Results were considered statistically significant at 95% confidence interval (p < 0.05).

Results: After week 1 - 4 of exposure, the mean SOD (Superoxide dismutase) value of the Negative control group (NC), Positive control (PC) group, diabetic groups exposed for weeks 1, 2, 3 and 4 expressed in U/ml were 299.41 ± 5.49, 217.38 ± 5.33, 220.56 ± 4.14, 240.45 ± 1.21, 258.19 ± 1.73 and 278.03 ± 1.98  respectively. The mean TAC (Total antioxidant capacity) value expressed in U/ml were 2.97 ± 0.10, 1.84 ± 0.04, 1.97 ± 0.04, 2.16 ± 0.02, 2.26 ± 0.02 and 2.46 ± 0.02 respectively. The mean GSH (Glutathione) expressed in µg/ml were 56.05 ± 0.60, 47.37 ±1.04, 47.94 ± 0.87, 50.80 ± 0.35, 53.07 ± 0.36 and 55.38 ± 0.33 respectively. The mean MDA (Malondialdehyde) expressed in nmol/l were 2.40 ± 0.13, 4.56 ± 0.28, 4.66 ± 0.06, 4.39 ± 0.01, 4.16 ± 0.03 and 3.70 ± 0.06 respectively. Comparison of different groups showed varying significant differences across groups.

Conclusion: Hyperglycaemia induced in rats studied led to an increase in oxidative stress, depletion of antioxidant parameters was observed. However, after treatment with Blue Whiting Fish (Micromesistus poutassous) Oil extracts, it was observed that there was improvement in the overall antioxidant status of the rats.