Effects of partially replacing fishmeal with corn gluten meal on growth, feed utilization, digestive enzyme activity, and apparent nutrient digestibility for juvenile white shrimp, Litopenaeus vannamei.

This experiment was conducted to assess the possibility of replacing fishmeal (FM, Fishmeal content of the control group: 30%) with corn gluten meal (CGM) at the following levels: 0, 10, 20, 30, 40, and 60%. The experimental diets, formulated to be isonitrogenous and isocaloric, were studied for their effects on growth, feed utilization, digestive enzyme activity and apparent nutrient digestibility in juvenile white shrimps, Litopenaeus vannamei (initial mean weight = 0.71 ± 0.01 g). Seven hundred twenty healthy and uniformed-size shrimp were distributed to six groups of three replicates, each with 40 shrimp in each tank (0.5 m3). Each experimental diet was fed to shrimp four times daily to apparent satiation at 7:00, 11:30, 17:00, and 21:30, respectively, for 8 weeks. At the end of the experiment, the total weight of fish in each tank was weighed and randomly selected for testing, including fish nutrient composition and digestive enzyme activity. Results showed that no significant differences were observed in the weight gain rate (WGR), feed coefficient rate (FCR) and specific growth rate (SGR) of shrimp after 30% FM was replaced with CGM (P > 0.05), but these indicators significantly decreased at higher replacement rates. As CGM content increased, the content of crude protein and phosphorus in the shrimp decreased significantly (P < 0.05), whereas the crude fat content first increased significantly and then decreased (P < 0.05). Compared to the control group, the protease activity was significantly lower in the 40% group and the lipase activity was significantly lower in the 60% group (P < 0.05). Amylase activity was significantly increased with increasing CGM levels (P < 0.05). The digestibility of protein and lipid was significantly reduced by CGM replacement of more than 30% FM (P < 0.05). As CGM content increased, the digestion of energy and dry matter was first significantly increased and then significantly decreased (P < 0.05). In the 30, 40, and 60% groups, the digestibility of all amino acids (AA), except methionine (Met), arginine (Arg) and serine (Ser), was significantly lower than in the control group (P < 0.05). In summary, FM could be partially replaced by CGM in the feed of L. vannamei. Based on the broken-line regression analysis of WGR, the optimal dietary CGM replacement was 27.47%.

The Effect of Glycerol Monolaurate on Intestinal Health and Disease Resistance in Cage-Farmed Juvenile Pompano Trachinotus ovatus.

This research studied the effects of glycerol monolaurate (GML) to diets on the digestive capacity, intestinal structure, intestinal microbiota, and disease resistance for juvenile pompano Trachinotus ovatus (mean weight = 14.00 ± 0.70 g). T. ovatus were, respectively, fed six diets containing 0.00, 0.05, 0.10, 0.15, 0.20, and 0.25% GML for 56 days. The highest weight gain rate was observed in the 0.15% GML group. In the intestine, amylase activities in the 0.10, 0.15, 0.20, and 0.25% GML groups were significantly increased, compared with 0.00% GML group (P < 0.05). Lipase activities in the 0.10 and 0.15% GML groups were significantly increased (P < 0.05). Similar significant elevations in the protease activities were also found in the 0.10, 0.15, and 0.20% GML groups (P < 0.05). Amylase activities were significantly higher in the 0.10, 0.15, 0.20, and 0.25% GML groups than that in the 0.00% GML group (P < 0.05). Villus lengths (VL) and muscle thicknesses (MT) of the 0.05, 0.10, 0.15, and 0.20% GML groups were significantly enhanced, and the villus widths (VW) in the 0.05, 0.10, and 0.15% groups were significantly increased (P < 0.05). Additionally, 0.15% GML significantly improved the intestinal immunity by upregulating interleukin 10 (il-10), increasing beneficial bacteria abundances (e.g., Vibrio, Pseudomonas, and Cetobacterium), downregulating nuclear factor kappa b (nf-κb) and interleukin 8 (il-8), and decreasing harmful bacteria abundances (e.g., Brevinema and Acinetobacter) (P < 0.05). After challenge test, GML significantly increased the survival rate (80%-96%) (P < 0.05). In addition, ACP and AKP activities in the GML-supplemented groups were significantly higher than those in the 0.00% GML group, and LZM activity was significantly higher in the 0.05, 0.10, 0.15, and 0.20% GML groups than that in the 0.00% GML group (P < 0.05). In summary, 0.15% GML significantly promoted the intestinal digestibility, improved the intestinal microflora, regulated intestinal immune-related genes, and increased resistance to V. parahaemolyticus of juvenile pompano T. ovatus.

Effect of Rice Protein Meal Replacement of Fish Meal on Growth, Anti-Oxidation Capacity, and Non-Specific Immunity for Juvenile Shrimp Litopenaeus vannamei.

This study assessed the effect of rice protein meal replacement for fish meal on the growth, nonspecific immunity, and disease resistance on juvenile shrimp Litopenaeus vannamei. Six groups of iso-nitrogenous and iso-lipid feeds named FM, R10, R20, R40, R60, and R80 were prepared by replacing 0%, 10%, 20%, 40%, 60%, and 80% in FM protein with RPM, respectively, and then fed to the shrimps (0.54 ± 0.01 g). An amount of 720 healthy and evenly sized shrimps were allocated to six groups (three replicates per group) and fed four times a day (7:00, 11:00, 17:00 and 21:00) for eight weeks. Results revealed no significant differences in WG, FCR, and SGR of shrimps after replacing FM with 10% RPM (p > 0.05). In the R10 and R20 groups, SOD and T-AOC activities were significantly higher than those in the FM group, whereas the opposite was observed for MDA content (p < 0.05). CAT, ACP, and LZM were all significantly higher in the R10, R20, and R40 groups than in the FM group (p < 0.05). GSH-Px activity in the R10 group was significantly higher than the activity in the FM group (p < 0.05). AKP, PO, TYS, GPT, and GOT activities were significantly higher in the R10 group than in the FM group (p < 0.05). Compared to the FM group, the eukaryotic translation initiation factor 3K (eif3k) gene was significantly up-regulated in the R10 group, whereas the penaiedin 3a (pen 3a) and anti-lipopolysaccharide factor (alf) genes were significantly up-regulated in the R10 and R20 groups (p < 0.05). The crustin a (cru a), immune deficiency (imd), and lysozyme (lzm) mRNA levels were significantly higher in the R10, R20, and R40 groups than in the other groups (p < 0.05). The prophenoloxidase (PO) mRNA levels in the R20 group were significantly higher than those in the FM group (p < 0.05). The replacement of 10−40% of FM with RPM improved the gut flora composition of shrimps, increasing beneficial bacteria (Bacteroidetes) abundance and reducing harmful bacteria (Aspergillus and Vibrio) abundance. After the challenge test of Vibrio parahaemolyticus (7 days), the cumulative mortality in the R10 group significantly decreased (p < 0.05). In conclusion, replacement of 10% FM by RPM significantly improved digestibility, protein synthesis, antioxidant capacity, and disease resistance in L. vannamei.

Enhanced CO2 Photoreduction through Spontaneous Charge Separation in End-Capping Assembly of Heterostructured Covalent-Organic Frameworks.

It is well known that charge separation is crucial for efficient photocatalytic solar conversion. Although some covalent-organic frameworks (COFs) exhibit visible-light harvest, the large exciton binding energies reduce their photocatalytic efficiencies. Herein, we developed a novel method to post-treat the olefin-linked COFs with end-capping polycyclic aromatic hydrocarbons (PAHs) for spontaneous charge separation. Interestingly, a type-II heterostructure is constructed in our perylene-modified COFs which displays drastically enhanced performance for photocatalytic CO2 reduction, with an efficiency of 8-fold higher than that of unmodified COF. A combination of electrochemical, steady-state, and time-resolved spectroscopic measurements indicates that such drastically enhanced performance should be attributed to photoinduced spontaneous charge separation in the heterostructure. These results illustrate the feasibility of engineering the charge-separation properties of crystalline porous frameworks at a molecular level for artificial photosynthesis.

Synergic emissions reduction effect of China's "Air Pollution Prevention and Control Action Plan": Benefits and efficiency.

Large amounts of fossil fuels that are consumed in association with the urbanization process, lead to billions of tons of greenhouse gases and air pollutants. Air pollution control policies have the synergic effects on carbon emissions reduction, but whether they can improve the synergic emission reduction efficiency (SERE) needs to be studied. 279 Chinese cities are selected as research samples. We evaluate the synergic effect of China's "Air Pollution Prevention and Control Action Plan" (APPCAP) from the perspectives of benefits and efficiency with the Difference-in-differences (DID) model. We further decompose the SERE into synergic emission reduction technological efficiency change (SEREEC) and synergic emission reduction technological change (SERETC) to analyze the internal impact mechanisms. The result shows that: (1) SERE has increased by 8 % from 2010 to 2017, for the expansion of the possibility boundary. (2) The APPCAP has co-benefit of carbon emissions reduction by 1.5 %, but inhibits the SERE increase by 1.2 % because of the lack of resource allocation efficiency improvement. (3) The APPCAP has an inhibitory effect on SEREEC and a promoting effect on SERETC. Therefore, the government should emphasize the source control and treatment efficiency, and further strengthen the system innovation for achieving urban sustainable development effectively.

Study on the Co-Benefits of Air Pollution Control and Carbon Reduction in the Yellow River Basin: An Assessment Based on a Spatial Econometric Model.

To assess the green and low-carbon development of the Yellow River Basin (YRB) in China, this study utilizes an evaluation index system based on the framework of driving force, pressure, state, impacts, response, and management, and it measured the comprehensive scores of the co-benefits of carbon reduction and air pollution control in the YRB. The global Moran index was used to analyze the spatial correlation characteristics of co-benefits, and a generalized spatial measurement model was constructed to demonstrate their spatial spillover effects. The results show that the co-benefits steadily increased every year. The co-benefits had a significant positive spatial correlation and showed a development trend of "up-down-up". According to the spillover effect test, the economic development level, education level, and intensity of environmental regulations had significant positive effects, while the level of urbanization and foreign investment had significant negative effects. Considering these results and the aim of promoting green and low-carbon development, clear detection of the spatial spillover characteristics of the co-benefits should be prioritized, followed by an understanding of the spatial transmission mechanism of carbon and air pollutant emission and transfer. Policy recommendations are also proposed including upgrading industrial structure, focusing on the development of modern services and high-tech industry, and strictly implementing the industrial environment access system.

New Insights into the Co-Occurrences of Glycoside Hydrolase Genes among Prokaryotic Genomes through Network Analysis.

Glycoside hydrolase (GH) represents a crucial category of enzymes for carbohydrate utilization in most organisms. A series of glycoside hydrolase families (GHFs) have been classified, with relevant information deposited in the CAZy database. Statistical analysis indicated that most GHFs (134 out of 154) were prone to exist in bacteria rather than archaea, in terms of both occurrence frequencies and average gene numbers. Co-occurrence analysis suggested the existence of strong or moderate-strong correlations among 63 GHFs. A combination of network analysis by Gephi and functional classification among these GHFs demonstrated the presence of 12 functional categories (from group A to L), with which the corresponding microbial collections were subsequently labeled, respectively. Interestingly, a progressive enrichment of particular GHFs was found among several types of microbes, and type-L as well as type-E microbes were deemed as functional intensified species which formed during the microbial evolution process toward efficient decomposition of lignocellulose as well as pectin, respectively. Overall, integrating network analysis and enzymatic functional classification, we were able to provide a new angle of view for GHs from known prokaryotic genomes, and thus this study is likely to guide the selection of GHs and microbes for efficient biomass utilization.

A novel optimal-hybrid model for daily air quality index prediction considering air pollutant factors.

Accurate and reliable air quality index (AQI) forecasting is extremely crucial for ecological environment and public health. A novel optimal-hybrid model, which fuses the advantage of secondary decomposition (SD), AI method and optimization algorithm, is developed for AQI forecasting in this paper. In the proposed SD method, wavelet decomposition (WD) is chosen as the primary decomposition technique to generate a high frequency detail sequence WD(D) and a low frequency approximation sequence WD(A). Variational mode decomposition (VMD) improved by sample entropy (SE) is adopted to smooth the WD(D), then long short-term memory (LSTM) neural network with good ability of learning and time series memory is applied to make it easy to be predicted. Least squares support vector machine (LSSVM) with the parameters optimized by the Bat algorithm (BA) considers air pollutant factors including PM2.5, PM10, SO2, CO, NO2 and O3, which is suitable for forecasting WD(A) that retains original information of AQI series. The ultimate forecast result of AQI can be obtained by accumulating the prediction values of each subseries. Notably, the proposed idea not only gives full play to the advantages of conventional SD, but solve the problem that the traditional time series prediction model based on decomposition technology can not consider the influential factors. Additionally, two daily AQI series from December 1, 2016 to December 31, 2018 respectively collected from Beijing and Guilin located in China are utilized as the case studies to verify the proposed model. Comprehensive comparisons with a set of evaluation indices indicate that the proposed optimal-hybrid model comprehensively captures the characteristics of the original AQI series and has high correct rate of forecasting AQI classes.