Search

Fish feeding habit determines the digestive tract structure and intestinal microflora. However, the relationship between feeding habit, digestive intestinal morphology, and microbial diversity of omnivorous, herbivorous, plankton feeder, and carnivorous fish from the same environment has not been compared. This study compared the digestive enzyme activities, intestinal morphology, and intestinal microflora of omnivorous (Carassius auratus), herbivorous (Ctenopharyngodon idellus), carnivorous (Siniperca chuatsi), and plankton feeder (Schizothorax grahami) fishes and predicted the potential functions of specific microflora on different nutrients. Twelve intestine samples were collected from each of the four fishes from Dianchi Lake. The composition and diversity of microbial communities were determined by using high‐throughput sequencing of 16S rDNA. The results showed that the carnivorous fish (S. chuatsi) had higher trypsin and pancrelipase activities in the hepatopancreas and enteropeptidase in the intestine, but lower amylase activities in the intestine. The carnivorous fish intestine had more microvilli branches and complex structures than other fish species in the order carnivorous > herbivorous > plankton feeder > omnivorous. The intestinal microflora diversity was higher in the omnivorous fish and followed the order omnivorous > herbivorous > plankton feeder > carnivorous. Acinetobacter species and Bacteroides species were the most dominant flora in the carnivorous and herbivorous fishes, respectively. Acinetobacter species and Pseudomonas species might help the host to digest protein, while Bacteroidetes species may help the host to digest cellulose. Taken together, feeding habit determines the digestive enzyme activities, intestinal tissue morphology, and differential colonization of fish intestinal flora. The knowledge obtained is useful in feed formulation and feeding practices for the studied fish species. [ABSTRACT FROM AUTHOR]

In order to solve the problem of dynamic pure-water electrical conductivity measurement in the process of calculating water content of oil-water two-phase flow of production profile logging in horizontal wells, a six-group local-conductance probe (SGLCP) is proposed to measure dynamic pure-water electrical conductivity in horizontal oil-water two-phase flow. The structures of conductance sensors which include the SGLCP and ring-shaped conductance probe (RSCP) are analyzed by using the finite-element method (FEM). In the process of simulation, the electric field distribution generated by the SGLCP and RSCP are investigated, and the responses of the measuring electrodes are calculated under the different values of the water resistivity. The static experiments of the SGLCP and RSCP under different mineralization degrees in horizontal oil-water two-phase flow are carried out. Results of simulation and experiments demonstrate a nice linearity between the SGLCP and RSCP under different mineralization degrees. The SGLCP has also a good adaptability to stratified flow, stratified flow with mixing at the interface and dispersion of oil in water and water flow. The validity and feasibility of pure-water electrical conductivity measurement with the designed SGLCP under different mineralization degrees are verified by experimental results.

To study the influence of Chinese Pinyin on detecting and correcting text errors in speech recognition, a text proofreading model based on Chinese semantic and phonological information was proposed. Five Pinyin coding methods were designed to construct the character-Pinyin embedding vector that was employed as the input of the Seq2Seq model based on gated recurrent unit. At the same time, the attention mechanism was adopted to extract the Chinese semantic and phonological information of sentences to correct speech recognition errors. Aiming at the problem of insufficient labeled corpus, a data augmentation method was introduced, which could automatically obtain annotated corpora by exchanging the initials or finals of Chinese Pinyin. The experimental results on AISHELL-3's public data show that phonological information is conducive to the text proofreading model to detect and correct text errors after speech recognition, and the proposed data augmentation method can improve the error detection performance of the model. [ABSTRACT FROM AUTHOR]

In order to investigate the effects of temperature on the growth performance, biochemical indexes and genes expression in juvenile hybrid sturgeon (Acipenser baerii♀ × Acipenser schrenckii♂), five temperature treatment groups (18 °C, 21 °C, 24 °C, 27 °C, 30 °C) were set in this study. After 25 days of domestication, the specific growth rate (SGR) and relative weight gain rate of juvenile sturgeon increased at first and then decreased with the increase in temperature in the range of 18–30 °C and reached the highest value at 21 °C. A quadratic equation was used to fit the regression equation of SGR and temperature (T). The result showed that the temperature of the maximum SGR is 23.45 °C. Moreover, the expression level of the growth hormone (gh) and the content of blood glucose (GLU) increased significantly at 21 °C, while the expression level of the growth hormone receptor (ghr) in the liver decreased significantly. When the temperature exceeded 27 °C, the thyroid hormone levels were significantly affected, and the levels of total antioxidants (T-AOC) and reduced glutathione (GSH) were significantly higher than those in the control group. In addition, with the increase in temperature, the expression levels of hsp70 and hsp90 in the liver increased significantly, while the expression level of the luteinizing hormone (lh) in the brain decreased significantly. To summarize, the effect of temperature on the growth and development of juvenile sturgeon mainly occurs through the effects of glucose metabolism, thyroid hormone level, total antioxidant capacity and growth-related genes. Therefore, in a temperature range between 21 and 24 °C, juvenile sturgeon can obtain the maximum growth rate and survival rate. [ABSTRACT FROM AUTHOR]

Arginine (Arg) is an important essential amino acid required for optimum fish growth. However, its role in plant‐rich diets on growth and the required level in juvenile Hemibagrus wyckioides are currently unknown. This study evaluated the effects of Arg supplementation in plant‐rich diets on growth, feed utilization, whole body composition, blood biochemical indicators and gene expressions of the target of rapamycin (TOR) signaling pathway in juvenile H. wyckioides. A total of 450 fish (6.40 ± 0.06 g) were randomized into six equal groups and fed on diets with graded Arg levels: 0 (control), 3, 6, 9, 12 and 15 g/kg of dry feed for eight weeks. The results revealed that specific growth rate (SGR) and feed conversion ratio of juvenile H. wyckioides were significantly improved and reduced, respectively in fish fed on 9 g/kg of Arg supplementation (p <.05). The optimum amount of dietary Arg content in plant‐rich diets for H. wyckioides was 63.77 g/kg diet based on SGR. Feeding fish with dietary Arg supplementation ranging from 9 to 12 g/kg improved significantly (p <.05) whole body protein contents and decreased lipid deposition. The mRNA levels of TOR, eukaryotic translation initiation factor 4E (4EBP) and ribosomal protein S6 kinase 1 (S6K1) in muscle and liver were significantly affected by increasing dietary Arg levels. Meanwhile, the mRNA relative expression levels of TOR and S6K1 in the liver and muscle increased significantly as Arg supplementation increased. On the other hand, the mRNA relative expression levels of 4EBP was significantly higher in fish fed on the 9 g/kg Arg diet compared to those fed on the control and 15 g/kg Arg diets. In conclusion, our current results indicate that dietary Arg supplementation in plant‐rich diets, might activate the TOR signaling pathway, which promotes protein synthesis and reduces lipid accumulation of H. wyckioides, resulting in improved growth. [ABSTRACT FROM AUTHOR]