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The rapid expansion of the aquaculture industry is accompanied by high organic and nutrient loadings from formulated feeds. This leads to water deterioration and pathogenic microorganisms. Natural biota (e.g., bacteria, phytoplankton, zooplankton, and zoobenthos) in ponds form important parts of cultured aquatic animals’ diets. They contain essential proteins, lipids, carbohydrates, amino acids, and fatty acids and are considered promising supplementary nutrition sources for cultured aquatic animals. Particularly, they are available to aquatic animals throughout the day, and an adequate supply of them as starter foods during the larvae stage ensures high survival. Since formulated feeds constitute more than 50% of aquaculture production costs, optimizing the utilization of natural biota and reducing dietary nutrient input without compromising animals’ growth should be a priority to improve the economic success and sustainability of aquaculture. From this scenario, the present review offers an updated view of the natural biota category in aquaculture systems, their nutritional components, and their contributions to the growth of cultured aquatic animals. Taken together, this review emphasizes the significant roles of natural biota playing in the growth of aquatic animals and encourages maximizing utilization of natural biota to improve feed conversion efficiency and aquaculture sustainability.

Sarcoptic mange, a disease caused by the burrowing mite Sarcoptes scabiei, is globally endemic and an emerging threat to wildlife. Although many studies have shown that wildlife diseases play key roles in biodiversity conservation, knowledge about sarcoptic mange is still insufficient. In this study, we aim to improve the understanding of the impacts of sarcoptic mange on wildlife populations, the mechanisms involved in its ecoepidemiology, and the associated risks to public and ecosystem health by investigating mass death events in gorals and serows in the Qinling Mountains. We conducted interviews with practitioners and local people in the central Qinling Mountains. From the same locations, we collected 24 cutaneous samples from various animals and surveillance data from infrared cameras. Pathological, parasitological and microbiological examinations of the samples were performed. Mite-induced cutaneous lesions, mites and eggs were observed in samples from dead gorals and one dead serow, but not in other species. Molecular analysis confirmed the mites to be S. scabiei that originated from rabbits. The data obtained from the interviews and infrared cameras indicated that the death of wildlife was related to sarcoptic mange infection and that there had been a decrease in the goral population since the outbreak of the disease. We confirmed that sarcoptic mange was the major cause of the mass death events and may have spread from the western to eastern Qinling Mountains. Based on our findings, we propose several protection strategies to help preserve biodiversity in the Qinling Mountains.

Overfeeding in aquaculture can lead to suboptimal growth and increased production costs. Red swamp crayfish, Procambarus clarkii, is one of the most noteworthy species cultured in China, but little information is available on the optimal feeding levels of this species, especially in ponds cultured with macrophytes. In this study, we tested the effects of five different feeding levels (20%, 40%, 60%, 80% and 100% satiation) of an artificial diet on growth performance and muscle composition of juvenile P. clarkii in 15 concrete ponds cultured with the macrophyte Hydrilla verticillata (three replicates for each treatment). The results showed that growth performance decreased only when feeding levels were below 60% satiation. Muscle composition analysis revealed that the moisture and ash contents of muscle did not vary significantly with feeding levels but that the lipid and protein contents of muscle significantly decreased when P. clarkii was fed to 40% satiation. Stable isotope analysis suggested a shift in crayfish diets to easily available H. verticillata when feeding levels decreased. With this study, we hope to encourage crayfish farmers to reduce feeding levels and increase natural food items such as macrophytes in cultured ponds to maximize crayfish yields and reduce production costs.