Document Type : Research Paper
Authors
1
student of the Faculty of Natural Resources of Gilan University
2
Professor in Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Iran.
3
International Sturgeon Research Institue
4
College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang, 443002, Hubei, China
10.22124/japb.2024.27770.1547
Abstract
Progress, ease of use and spread of plastics waste have led to the current era, being called the era of plastic. The stability and consistency of plastics have led to a large accumulation in water resources and environmental pollution. Large pieces of plastic can be collected, but it is not possible to collect particles smaller than 5 mm, which are called Microplastics, and they have many ecological risks for aquatic life. Polyethylene is one of the most abundant particles that can be found everywhere. This research aims to investigate the effects of high-density polyethylene (HDPE) microplastics on the growth indices and food conversion ratio (FCR) of juvenile stellate sturgeon, Acipenser stellatus. This research was carried out in the International Sturgeon Research Institute. Twelve 200-L tanks, in each tank 10 stellate sturgeon fry were stocked with an average weight of 18-20 g, for 30 days, to evaluate the effects of adding microplastics to the diet (encapsulated). In this study, three treatments with 3 repetitions were fed with diet containing 1, 10 and 100 mg/kg for each treatment and a control group without any additive. The fish were fed three times a day. The biometric characteristics of the fish were performed at the end of the course and after starving the fish for 24 hours, with an accuracy of 0.1 g for weight and 1 mm for total length. The growth indices such as final weight, final length, specific growth rate (SGR), percent body weight gain (BWI), condition factor (CF), average daily growth (ADG), feed conversion ratio (FCR) and survival rate (SR) were assayed. According to the present research, according to the investigations obtained, it was found that high-density polyethylene microplastics on exposed fish caused a decrease in appetite and desire for diet. In addition, some adverse effects were observed on growth parameters such as the average final weight (p = 0.045), the percentage of weight gain (p = 0.042), daily growth (p = 0.032), specific growth rate (p = 0.041) and food conversion ratio (p = 0.042) with a significant difference compared to the control. The presence of microplastics in diet caused false satiety in the fish, leading to not eating with an increase in the doses of microplastics in the diet. The presence of microplastics in diet with doses of 1, 10 and 100 mg/kg of diet reduced the growth of fish and reduced diet digestion and absorption of food and had adverse effects on juvenile fish such as weight loss and lack of proper growth.
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