Phylogenetic analysis based on the complete mitochondrial genome of Discogobio brachyphysallidos (Cypriniformes: Cyprinidae) suggests the need for taxonomic revision at the genus level.

Discogobio brachyphysallidos Huang 1989 is a Cyprinidae fish species that is endemic to the upper Pearl River. In the present study, the complete mitochondrial genome of D. brachyphysallidos collected from the Nanpanjiang River was sequenced and annotated. The mitochondrial genome encompassed 13 protein-coding genes, two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and the control region (D-loop). The total length of the mitochondrial genome was determined to be 16,594 base pairs (bp), with a GC content of 41.7%. Phylogenetic analyses revealed that D. brachyphysallidos may be a sister to D. longibarbatus and D. macrophysallidos. These findings provide insight into the genetic information and phylogenetic relationships of D. brachyphysallidos.

Influence of dietary fermented Folium mori on growing performance, lipometabolism and disease resistance of golden pompano Trachinotus ovatus.

Folium mori, as a plant unconventional feedstuff, are comparatively available due to cost-effectiveness, whereas their usage as aquafeed in pure form is restricted owing to the great fibre and antinutritional factors (ANFs) levels. Thereof, several methods of processing are introduced to remove antinutrient factors from the plant products, leading to improvement of bioactivity and digestibility. The assay was completed to evaluate the method of fermentation and the role of dietary fermented Folium mori (FFM) in golden pompano. Each of 5 diets with FFM at contents of 0.0%, 2.0%, 4.0%, 6.0% and 8.0% (D0.0, D2.0, D4.0, D6.0 and D8.0) was fed to the fishes with original body weight of 9.02g in triplicate sea cages for 56 days. The outcomes revealed that FFM in D4.0 and D6.0 elevated the growing performance of the fishes and the growing performance of D4.0 was remarkably improved in contrast to D0.0 and D2.0(P < 0.05). Whole body lipidic levels were obviously elevated when the diet FFM contents were below 8.0% (P < 0.05), whereas the contents of muscular moisture were generally reduced. In addition, FFM significantly increased serum high density lipoprotein (HDL) and remarkably reduced overall triglyceride (TG) in D2.0 to D6.0(P < 0.05). Moreover, FFM remarkably elevated the activities of lipase of stomach and hepatopancreas in contrast to D0.0 (P < 0.05) as well as intestinal tryptic enzyme in the entire FFM groups (P < 0.05). Eventually, FFM remarkably ameliorated disease-resistant characters of golden pompano to Vibrio harveyi in D4.0 and D6.0 (P < 0.05) and the RPS in D4.0 was optimal. To sum up, the present research displayed favorable role of FFM in growing performance, digestion, lipometabolism and disease-resistant characters, and the recommendation as to the supplementation content of diet FFM in compound feed of juvenile golden pompano is 4.0% as per the experiment status herein.

Interactions between dietary carbohydrate and thiamine: implications on the growth performance and intestinal mitochondrial biogenesis and function of Megalobrama amblycephala.

A12-week experiment was conducted to evaluate the influences of thiamine ongrowth performance, and intestinal mitochondrial biogenesis and function of Megalobramaamblycephala fed a high-carbohydrate (HC) diet. Fish (24·73 (sem 0·45) g) were randomly assigned to one of four diets: two carbohydrate (CHO) levels (30 and 45 %) and two thiamine levels (0 and 1·5 mg/kg). HC diets significantly decreased DGC, GRMBW, FIMBW, intestinal activities of amylase, lipase, Na+, K+-ATPase, CK, complexes I, III and IV, intestinal ML, number of mitochondrial per field, ΔΨm, the P-AMPK: T-AMPK ratio, PGC-1ß protein expression as well as the transcriptions of AMPKα1, AMPKα2, PGC-1ß, mitochondrial transcription factor A, Opa-1, ND-1 and COX-1 and 2, while the opposite was true for ATP, AMP and reactive oxygen species, and the transcriptions of dynamin-related protein-1, fission-1 and mitochondrial fission factor. Dietarythiamine concentrations significantly increased DGC, GRMBW, intestinal activities of amylase, Na+, K+-ATPase, CK, complexes I and IV, intestinal ML, number of mitochondrial per field, ΔΨm, the P-AMPK:T-AMPK ratio, PGC-1ß protein expression as well as the transcriptions of AMPKα1, AMPKα2, PGC-1ß, Opa-1, ND-1, COX-1 and 2, SGLT-1 and GLUT-2. Furthermore, a significant interaction between dietary CHO and thiamine was observed in DGC, GRMBW, intestinal activities of amylase, CK, complexes I and IV, ΔΨm, the AMP:ATP ratio, the P-AMPK:T-AMPK ratio, PGC-1ß protein expression as well as the transcriptions of AMPKα1, AMPKα2, PGC-1ß, Opa-1, COX-1 and 2, SGLT-1 and GLUT-2. Overall, thiamine supplementation improved growth performance, and intestinal mitochondrial biogenesis and function of M. amblycephala fed HC diets.

Molecular characterization of thioredoxin-interacting protein (TXNIP) from Megalobrama amblycephala and its potential roles in high glucose-induced inflammatory response.

This study aimed to characterize the full-length cDNA of thioredoxin-interacting protein (TXNIP) from Megalobrama amblycephala, and investigate its roles in high glucose (HC)-induced inflammatory response. The cDNA obtained covered 2706-bp with an open reading frame of 1203-bp encoding 400 amino acids, compared to Cyprinus carpio, it showed 89.96% homology. The highest expression of txnip was observed in head kidney followed by spleen and liver. After a 12-week feeding trial, high-carbohydrate diet remarkably increased txnip expression in liver and white muscle. Glucose administration resulted in a remarkably increased liver txnip expression, which peaked at 1 h. Thereafter, the expression decreased remarkably to the basal value at 12 h. However, insulin injection resulted in a significant decrease in txnip expression with minimum values attained at 2 h. Subsequently, it gradually increased to the normal values. Moreover, in the in-vitro study, over-expression of txnip along with remarkably increased il-1ß and il-6 expression in hepatocytes, and its knockdown led to remarkably reduced il-1ß expression. Furthermore, metformin treatment remarkably increased the cell viability and trx expression of hepatocytes under high glucose, while the opposite was true for ROS levels, LDH activity, the ALT/AST ratio, Txnip protein content and the transcriptions of txnip, tnfα and il-1ß.

Effects of woody forages on biodiversity and bioactivity of aerobic culturable gut bacteria of tilapia (Oreochromis niloticus).

The present study investigated the effects of four woody forages (Moringa oleifera Lam (MOL), fermented MOL, Folium mori (FM) and fermented FM) on biodiversity and bioactivity of aerobic culturable gut bacteria of tilapia (Oreochromis niloticus) by a traditional culture-dependent method. A total of 133 aerobic culturable isolates were recovered and identified from the gut of tilapia, belonging to 35 species of 12 genera in three bacterial phyla (Firmicutes, Actinobacteria and Proteobacteria). Among them, 6 bacterial isolates of Bacillus baekryungensis, Bacillus marisflavi, Bacillus pumilus, Bacillus methylotrophicus, Proteus mirabilis and Pseudomonas taiwanensis were isolated from all the five experimental groups. The Bray-Curtis analysis showed that the bacterial communities among the five groups displayed obvious differences. In addition, this result of bioactivity showed that approximate 43% of the aerobic culturable gut bacteria of tilapia displayed a distinct anti-bacterial activity against at least one of four fish pathogens Streptococcus agalactiae, Streptococcus iniae, Micrococcus luteus and Vibrio parahemolyticus. Furthermore, Bacillus amyloliquefaciens and Streptomyces rutgersensis displayed strong activity against all four indicator bacteria. These results contribute to our understanding of the intestinal bacterial diversity of tilapia when fed with woody forages and how certain antimicrobial bacteria flourished under such diets. This can aid in the further exploitation of new diets and probiotic sources in aquaculture.

Woody forages effect the intestinal bacteria diversity of golden pompano Trachinotus ovatus.

To understand the effect of woody forages on golden pompano (Trachinotus ovatus) intestinal bacteria diversity and exploit new aquafeed ingredients, the diets of Moringa oleifera Lam (MOL), Broussonetia papyrifera (BP), Neolamarckia cadamba (NC) and Folium mori (FM) formulated with 70% of reference (Ref) diet and 30% of the four woody plants leaves were fed to golden pompano with initial body weight of 34.4 ± 0.5 g for 56 days, respectively. Bacteria diversity of golden pompano intestine and tank water (W) samples were analyzed using high-throughput illumina sequencing and the result indicated that the dominate phyla of golden pompano intestine were Proteobacteria, Bacteroidetes, Firmicutes and Fusobacteria. Proteobacteria in BP was significantly higher than those in NC (P < 0.05). Firmicutes in NC were significantly higher than those in BP and FM (P < 0.05). At genera level, Lactobacillus in NC was significantly higher than those in BP, MOL and FM groups (P < 0.05). The PCoA and heat map analyses showed that the intestinal bacteria community of golden pompano fed with woody forages and Ref diet presented higher similarity and the bacteria community of golden pompano intestine were clearly distinguished from those of W. Phylogenetic investigation of communities by reconstruction of unobserved states showed that the intestinal bacteria dominant metabolism pathways of golden pompano fed with woody forages and Ref diet were biosynthesis of amino acids and carbon metabolism. Overall, the present study first successfully characterized the intestinal bacteria diversity of golden pompano.