فهرست نشریات علمی دسترسی آزاد ایران

Oxidation is a key factor in reducing the quality of aquatic feed and lead to undesirable changes in the nutritional composition of the diet. The usageof antioxidants in aquatic diets can reduce the damage caused by oxidative stress. Although synthetic antioxidants are used in livestock and aquatic feed, there are growing concerns about their toxicity and long-term effects on consumer health. Due to possessing a wide range of secondary metabolites, seaweeds have been considered as a natural source for producing natural antioxidants. Therefore, this research investigated the in vitro antioxidant properties of the red seaweed Gelidium pusillum from the Oman Sea. The seaweed was collected during low tide from the Oman Sea, dried, and powdered. Extraction was performed using methanol, chloroform, dichloromethane, and hexane solvents over 24 hours. After calculating the total phenolic content in the extracts, the antioxidant properties of the extracts were evaluated using three methods: free radical scavenging (DPPH), ferrous ion chelating activity, and reducing power. The IC50 value was calculated by plotting a graph. For statistical analysis, one-way ANOVA was used, and the Tukey post-hoc test was used for mean comparison. Experiments were performed in triplicate. Investigation of extraction yield revealed that the methanolic extract (1.5%) had the highest extraction yield compared to dichloromethane, chloroform, and hexane extracts. Examination of total phenolic compounds in Gelidium pusillum showed that the methanolic extract (23.14 mg GA/100g) had the highest total phenolic content, and the hexane extract (22.9 mg GA/100g) ranked second. The highest free radical scavenging activity was observed in the methanolic extract (90%), followed by the hexane extract (80%). The highest chelating activity (31.3%) was observed at a concentration of 1 mg/mL of the methanolic extract. The methanolic extract showed the highest reducing power (λ=0.56) among the extracts at different concentrations and had a significant difference with the other three extracts (p< 0.05). The antioxidant effect was dose-dependent and all extracts showed a significant difference in all three tests compared to the positive control (p< 0.05). Total phenolic content had a positive effect on the antioxidant activity of the seaweed extract, and solvents with higher total phenolic content exhibited higher antioxidant activity compared to other extracts. The high free radical scavenging activity of the methanolic extract confirmed its potential for further studies. Accordingly, investigating the in vivo activity of the methanolic seaweed extract in aquatic diets is recommended.