Integrated multi-trophic aquaculture (IMTA) has been proposed as a potential solution to supply aquatic food in an environmentally friendly way. However, little is known regarding the impacts of IMTA on the growth rates and food quality of both animals and plants, as well as the seasonal effects. In this study, we conducted field mesocosm experiments using monoculture and coculture systems with the shrimp Litopenaeus vannamei and the macroalga Ulva linza for four weeks in different seasons (autumn, spring and summer) to address the research gap. To evaluate the environmental pollution caused by shrimp culture, there was no water exchange for culture systems including shrimps. Compared to monoculture of L. vannamei , coculture with U. linza significantly reduced dissolved inorganic nitrogen (DIN, 98.5–99.0%) and dissolved inorganic phosphorus (DIP, 98.2–98.8%) but enhanced dissolved oxygen (DO, 56.2–68.7%) and pH (10.7–18.6%) by the end of culture. Compared to monoculture, coculture stimulated the growth rates of L. vannamei by 38.1–58.8% and U. linza by 241.9–290.4% in all seasons, and increased the lipid content of L. vannamei by 24.2% in autumn and by 37.9% in summer and the contents of protein and ash of U. linza by 23.8–29.0% and by 27.6–68.6%, respectively, in all seasons. Coculture enhanced the content of most amino acids in U. linza and the content of total fatty acids (FA) and polyunsaturated fatty acids in L. vannamei in all seasons in comparison with monoculture. In addition, coculture lifted swelling capacity by 28.9–40.5%, water holding capacity by 39.8–43.3% and oil holding capacity by 31.4–32.4% for U. linza in autumn and summer. Apart from relieving eutrophication , deoxygenation and acidification, IMTA increased growth rates of both shrimp and Ulva and improved functional properties of U. linza , suggesting a green and productive aquaculture mode.
Chunmei Xu,Zhengqun Zhang,Kaidi Cui,Yunhe Zhao,Jingkun Han,Feng Liu,Wei Mu
To better understand the sublethal effects of cyantraniliprole on the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae), several studies were carried out to investigate sublethal effects on development stages, population parameters, feeding indices and nutrient content of A . ipsilon . The result of a bioassay showed that cyantraniliprole had high toxicity against A . ipsilon fourth-instar larvae with an LC 50 of 0.354 μg.g −1 using an artificial diet. Compared with controls, sublethal doses of cyantraniliprole at LC 5 , LC 20 and LC 40 levels prolonged larval and pupal duration and extended mean generation time and total preovipositional period. In addition, survival rate, reproductive value, intrinsic and finite rates of increase and net reproduction rate declined significantly. Meanwhile, cyantraniliprole had markedly antifeedant effects; decreased the relative growth rate (RGR), the relative consumption rate (RCR), the efficiency of conversion of ingested food (ECI), the efficiency of conversion of digested food (ECD); and increased the approximate digestibility (AD) significantly. This phenomenon contributed to the decrease of nutrient contents, including lipids, protein and carbohydrates, to the point that insufficient energy was available for normal growth. Therefore, sublethal concentrations of cyantraniliprole decreased growth speed and reduced population reproduction of A . ipsilon . This result provides information useful in integrated pest management (IPM) programs for A . ipsilon .