Manipulative experiments networks on response and adaptation of terrestrial ecosystems to environmental changes: Building the research methods and technology system.

The feedback relationship between organisms or ecosystems and environment has been a key issue in ecological research. Manipulative experiments with changing biological or environmental factors and large-scale field experiment networks were regarded as effective approaches to understand and accurately quantify the process and mechanisms underlying ecosystem response and adaptation to environmental changes. In recent years, a few networks have been developed, including large-scale networks of field physics simulation experiment (i.e., ECOTRON), ecosystem analysis and experiment platform (AnaEE), international Drought Network, Nutrient Network, and experiment networks based on regional ecological observation stations (i.e., USA-ILTER) at global scale. The development of continent-scale experiment network platform is attracting more attention from the academic community, and will play a more important role in understanding the process and mechanism underlying ecosystem responses to environmental change. We reviewed the development of method and experiment system of ecosystem manipulative experiments, and clearly pointed out that different experiments should form a joint collaborative system to answer fundamental scientific questions about the response and adaptation of ecosystem to global environment change. Manipulative experiments could be classified into four types: 1) Physiological and ecological experiments in closed laboratory equipment; 2) semi-open experiments with changing environmental factors in the field; 3) near-natural field experiments; 4) experiment networks based on field ecological station. Furthermore, we discussed the trends in network design of manipulative experiments focusing on ecosystem response and adaptation to environmental changes and the advantages of large-scale experiments based on natural environmental gradients. We put forward a proposal of integrating the technical advantages of different types of experiments and developing a new generation of field experiment network system. The study discussed the research system based on field experiment network, demonstrated the possibility to understand the patterns and mechanisms of the ecosystem short-term response and long-term adaptation to environmental changes, and proposed some equations to quantify the environmental response of ecosystems. The application of the design plan of the manipulative experiments network proposed here will greatly promote the scientific research level of ecosystems and environmental changes in China and even over the whole world, which has important scientific significance for the national response to climate change and ecological environmental construction.

Effects of dietary fermentation concentrate of Hericium caput-medusae (Bull.:Fr.) Pers. on growth performance, digestibility, and intestinal microbiology and morphology in broiler chickens.

BACKGROUND: The present study was undertaken to investigate the effects of fermentation concentrate of Hericium caput-medusae (Bull.:Fr.) Pers. (HFC) on growth performance, digestibility, intestinal microbiology, and intestinal morphology in broiler chickens. A total of 600 male Arbor Acres broilers were randomly divided into five dietary treatments (20 broilers per pen with six pens per treatment): CON (basal diet), ANT (basal diet supplemented with 5 mg kg(-1) flavomycin) and HFC (basal diet supplemented with 6, 12, and 18 g kg(-1) HFC). The experimental lasted for 42 days. RESULTS: The results revealed that the average daily gain [linear (L), P < 0.01; quadratic (Q), P < 0.01] of broilers increased when the HFC levels increased during the starter (days 1-21), finisher (days 22-42), and the overall experiment period (days 1 to 42). In the small intestinal digesta and the caecum digesta, the Escherichia coli count (L, P < 0.05; Q, P < 0.001) decreased while the Lactobacilli count (L, P < 0.01; Q, P < 0.001) and Bifidobacteria count (L, P < 0.001; Q, P < 0.001) increased when the HFC levels increased. The crude protein digestibility of broilers (L, P < 0.01; Q, P < 0.001) increased when the HFC levels increased. In the duodenum, jejunum, and ileum of broilers, the villus height and villus height to crypt depth ratio (L, P < 0.001; Q, P < 0.001) increased when the HFC levels increased. CONCLUSION: Dietary supplementation with HFC increased gut Lactobacilli and Bifidobacteria counts and inhibited E. coli growth, improved nutrient utilisation and intestine villus structure, and thus improved the growth of broilers.