Rhynchocypris Lagowskii Research Articles

Length-Weight Relationships for Ten Fish Species from Rivers in the Qinling Mountains, China

Length-weight relationships (LWRs) were reported for ten fish species (Abbottina rivularis, Hemibarbus labeo, Hemibarbus maculatus, Onychostoma macrolepis, Opsariichthys bidens, Rhynchocypris lagowskii, Schizothorax prenanti, Sinibrama macrops, Zacco platypus, and Siniperca scherzeri). Fishes were collected from 62 sampling stations covering an area of ∼7000 km2 in the Qinling Mountains, characterized by unique fauna and distribution pattern, using gillnets and ground cages during June to December 2022. The intercept a ranged from 0.013 for S. prenanti to 0.060 for H. labeo, and the slope b ranged from 2.537 for H. labeo to 3.079 for Z. platypus.

Beneficial effects of indigenous Bacillus spp. on growth, antioxidants, immunity and disease resistance of Rhynchocypris lagowskii

This study aimed to investigate the effect of Bacillus aryabhattai (LSG3-7) and Bacillus mojavensis (LSG3-8) on growth performance, antioxidant capacity, and immune response in Rhynchocypris lagowskii (Dybowski, 1869), at the trial and challenge periods. A 630 healthy fish (10.76 ± 0.05) were randomly divided into six groups: control group (D1) was fed the basal diet, D2 and D3 were supplemented with LSG 3–7 and LSG3-8 (1 × 108 CFU/g) for both of them, whereas D4 was supplemented with a mixture of both bacteria (0.5 × 108 CFU/g each), and D5 was supplemented with LSG3-7 0.75 × 108 CFU/g + LSG3-8 0.25 × 108 CFU/g, and D6 supplemented with LSG3-7 0.25 × 108 CFU/g + LSG3-8 0.75 × 108 CFU/g. After the trial, Aeromonas hydrophila was used in a challenge test for 14 days. Treatments showed significant differences (p < 0.05) in growth performance and antioxidant capacity (CAT, CuZn-SOD, GPX) in the liver and intestine compared to the control. The antioxidant-related genes CAT, CuZn-SOD, GPX, and Nrf2 in the liver and intestine showed upregulation compared with the control group. Serum IgM, LZM, C3, C4, and AKP showed a favorable superiority (p < 0.05) in treatments (D2 – D6) at the trial and challenge test compared to controls. In parallel, immune-related genes (IgM, NF-κB, TLR-1, TLR-2, and MyD88) showed an up-regulated level (p < 0.05) in treatments (D2 – D6) compared to the control. In addition, pro-inflammatory cytokines (IL-1, TNF-α) showed a downregulated level in treatments (D2 – D6). After the challenge test, the immune-related genes in the liver and muscle showed an up-regulated level in treatments compared to the controls. The survival rate showed a significant increase (p < 0.05) in the treatment groups (D2 – D6) compared to the control. Overall, individuals and the bacterial mixture of B. aryabhattai and B. mojavensis could improve the growth performance, antioxidant capacity, immune capacity, and survival rate of R. lagowskii and prevent side effects of A. hydrophila. However, B. mojavensis showed a slight improvement compared to B. aryabhattai without a significant difference between them.

Characterization of Bacillus spp. isolated from the intestines of Rhynchocypris lagowskii as a potential probiotic and their effects on fish pathogens

Probiotics sourced from fish intestinal microbiota have a merit over other bacterial sources due to colonization ability and effective time. This study aimed to evaluate the bacilli isolated from the Rhynchocypris lagowskii intestines and their validity as a probiotic. Three isolates were selected (LSG 2–5, LSG 3–7, and LSG 3–8) and defined by morphological and 16S rRNA analysis as Bacillus velezensis, Bacillus aryabhattai, and Bacillus mojavensis, respectively. Results showed the strain tolerant abilities to gastrointestinal fluid, bile salt, pH, and temperature expotures. Additionally, all bacterial strains showed anti-pathogenic activity against at least four strains out of six tested pathogen strains (Staphylococcus aureus, Aeromonas hydrophila, Escherichia coli, Aeromonas veronii, Edwardsiella, and Aeromonas sobria). The bacterial strains also showed a high percentage of co-aggregation activity, more than 70%, with Aer. hydrophile, Staph. epidermidis, and Klebsiella aerogenes. At the same time, the results of competition, rejection, and substitution activity with Aer. hydrophila and Aer. veronii indicated the ability of the isolated strains to reduce the adhesion of pathogens to mucin. All strains showed safety properties, non-hemolytic, and sensitivity characteristics for most of tested antibiotics. In vivo test after injecting these strains into fish at various concentrations showed no side effects in the internal or external organs of fish compared to controls, proving that this is safe for these fish. Furthermore, the three strains produced lipase, amylase, and protease enzymes. The strains also showed bile salt hydrolase activity and biofilm formation, allowing them to tolerate stressful conditions. Conclusion: Based on these strains characteristics and features, they could be considered a promising candidate probiotic and can be used as an anti-pathogenic, especially in aquaculture.

Effect of Bacillus amyloliquefaciens LSG2-8 on the intestinal barrier function of Amur minnow (Rhynchocypris lagowskii).

Probiotics have been widely used in aquaculture. This article aims to study the effect of Bacillus amyloliquefaciens LSG2-8 on the intestinal barrier function of Rhynchocypris lagowskii. B. amyloliquefaciens LSG2-8 were added to R. lagowskii basal diets (CK) as additives at four concentrations: 1.0 × 106 (D-6), 1.0 × 107 (D-7), 1.0 × 108 (D-8) and 1.0 × 109 (D-9) CFU/g by dry weight of basal diet. After a 56 days feeding experiment, the intestinal digestive enzymes and immune enzymes activity of R. lagowski on group D-6, D-7, D-8 and D-9 diet were significantly higher than the control (P < 0.05). In molecular experiments, we found that the levels of TGF-β mRNA, IL-10 mRNA, ZO-1 mRNA and Claudin-3 mRNA in group D-8 R.. lagowskii were significantly higher (P < 0.05) than the control and other groups. Furthermore, the levels of IL-1β and IL-8 mRNA of R. lagowski on group D-6, D-7, D-8 and D-9 diet were significantly lower than the control (P < 0.05). In addition, we found that B. amyloliquefaciens LSG2-8 can regulate the intestinal flora balance and improve the intestinal structure of R. lagowskii. In conclusion, B. amyloliquefaciens LSG2-8 can improve the intestinal barrier function of R. lagowskii,and can be used as a feed additive in aquaculture.

Species composition and distribution of fishes at the shallow waters of the low and middle Amur river in summer, 2018 and 2019

Based on the data of seine surveys (June 2018 and 2019, 57 and 38 catches), species composition and structure of fish communities of the middle and low Amur River were studied. The species richness of fish in the low Amur River is higher compared to the middle Amur River, 37 and 22 species, respectively. Upstream of the Amur River, fish biomass falls. At the beginning of summer, its average value in the low Amur was equal 1,354±0,209 g/m2, in the middle Amur – 0,324±0,058 g/m2. In the middle Amur River, the fish biomass was dominated by Hemiculter spp. (29,1%), Opsariichthys bidens (28,0%), Leuciscus waleckii (22,1%), Squalidus spp. (7,5%) and Tachysurus sinensis (3,9%). In the catches on the low Amur River, the fish biomass was dominated by Hemiculter spp. (26,2%), Leuciscus waleckii (21,0%), Hypomesus olidus (18,1%), Rhynchocypris lagowskii (7,6%), Carassius gibelio (7,2%), Rhodeus sericeus (5,0%) and Xenocypris macrolepis (4,6%). Local maxima of fish abundance were determined by the ecological preferences of most common fish species (in particular, their reopreferendum).

The protective role of vitamin C on intestinal damage induced by high-dose glycinin in juvenile Rhynchocypris lagowskii Dybowski

This study was to evaluate the mitigative effects of vitamin C (VC) on growth inhibition and intestinal damage induced by glycinin in juvenile Rhynchocypris lagowskii Dybowski. 270 healthy juvenile Rhynchocypris lagowskii Dybowski (4.65 ± 0.04 g) were randomly divided into 3 treatments, and fed with control diet, 80 g/kg glycinin diet and 80 g/kg glycinin+200 mg/kg VC diet respectively for 8 weeks. The results showed that glycinin significantly decreased the weight gain rate, specific growth rate, protein efficiency rate, feed efficiency rate and feeding rate of fish compared with the control group (P < 0.05), while VC supplementation improved the growth performance and feed utilization efficiency, and reached a level similar to the control group. Similarly, VC significantly increased the crude protein content of muscle and whole-body, and hepatopancreas and intestinal protease activities of fish fed with glycinin diet (P < 0.05). The distal intestine of fish in glycinin group showed typical damage characteristics, including breakage and atrophy of intestinal mucosal fold, and increased intestinal mucosal permeability. However, fish fed the glycinin + VC diet showed an unimpaired normal intestinal morphology. Usefully, VC supplementation could also restore impaired immune function and antioxidant capacity. VC down-regulated the mRNA levels of pro-inflammatory cytokines TNF‐α and IL-1β, and up-regulated the mRNA levels of anti-inflammatory cytokines IL-10 and TGF-β in the distal intestine of fish fed with glycinin. Furthermore, glycinin exposure could reduce the mRNA levels of HO-1, CAT and GPx by inhibiting the activation of Nrf2-Keap1 signaling pathway, while VC supplementation reversed this phenomenon and maintained the homeostasis of antioxidant defense system. Concluded, glycinin causes growth inhibition, digestive dysfunction and intestinal damage of Rhynchocypris lagowskii Dybowski, while sufficient VC intake is beneficial for fish to resist the adverse effects of glycinin.

Assessment of Aquatic Ecological Health Based on the Characteristics of the Fish Community Structures of the Hun River Basin, Northeastern China

Long-term ecological restoration can restore aquatic ecosystems to a certain extent and alleviate the crisis of freshwater fish biodiversity. In order to explore the fish community distribution patterns and key factors after ecological restoration and the health status of the watershed, fish and environmental data were collected from 39 sampling points in the Hun River Basin in the spring and autumn of 2021. A total of 51 fish species belonging to 11 families and 37 genera were collected during the survey, and the dominant species were Rhynchocypris lagowskii, Zacco platypus, Carassius auratus and Pseudorasbora parva. Compared with the results of past studies, the number of fish species has increased. The study found that the distribution of fish along the longitudinal gradient of the watershed showed obvious spatial differences and was divided into two groups. The results of canonical correspondence analysis (CCA) showed that agricultural land, urban land and grassland were the key factors for the spatial variation in fish communities in the Hun River Basin. The results of the F-IBI evaluation showed that the health status of the Hun River was fair or above fair, among which healthy, good, fair, poor and bad points accounted for 5.13%, 30.77%, 33.33%, 25.64% and 5.13%, respectively. The upper and middle reaches of the Hun River Basin were in better health, while the lower reaches were in poorer health, which was mainly affected by the intensity of human activities in different regions. This study will help watershed managers to make targeted restoration and protection measures for different regions.

Dietary L-carnitine supplementation changes lipid metabolism and glucose utilization of Rhynchocypris lagowskii fed diets with different lipid sources.

The widely available crop oil is an effective alternative to the increasingly scarce marine fish oil. However, simple alternative strategies have led to declining growth and the edible value of farmed fish. It is worthwhile to explore the effects of micro supplements in diets to improve the tolerance of fish to different dietary lipid sources, which finally optimizes the feeding strategies. This study aimed to investigate the regulation of L-carnitine and dietary oil conditions on nutrient composition, lipid metabolism, and glucose regulation of Rhynchocypris lagowskii. Four diets were prepared according to fish oil, fish oil supplemented with L-carnitine, corn oil, and corn oil supplemented with L-carnitine, and FO, LCFO, CO, and LCCO were labeled, respectively. R. lagowskii was fed experimental diets for 8weeks, and the glucose tolerance test was performed. The CO diet significantly resulted in higher crude lipid content in muscle but a lower level of serum lipid parameters of R. lagowskii than the FO diet. However, dietary L-carnitine supplementation significantly reduced the crude lipid content in the hepatopancreas and muscle of the fish fed with the CO diet yet increased the serum lipid parameters. Additionally, the crude lipid content of muscle was reduced in the fish fed with an FO diet supplemented with L-carnitine. Compared with the FO diet, the CO diet significantly reduced the ratio of n3/n6 polyunsaturated fatty acid in the hepatopancreas and muscle of R.lagowskii. Dietary L-carnitine supplementation significantly reduced the contents of total saturated fatty acids and total monounsaturated fatty acids in hepatopancreas under both dietary lipid sources. The CO diet significantly up-regulated the expression of genes related to lipid uptake and adipogenesis in hepatopancreas, including lipoprotein lipase (lpl), acetyl-coenzyme A carboxylase alpha (accα), and sterol regulatory element binding protein-1 (srebp1), compared with the FO diet. While dietary L-carnitine supplementation significantly down-regulated the expressions of lpl, accα, srebp1, and fatty acid synthase in hepatopancreas and muscle of fish under both dietary lipid sources, along with up-regulated expression of carnitine palmitoyltransferase 1 in hepatopancreas. Moreover, the fish fed with a CO diet significantly increased the expression of glucose uptake and clearance and significantly down-regulated the expressions of glucose regulation-related genes, including glucose transporter 1, glycogen synthase 1, and phosphofructokinase in hepatopancreas and muscle, resulting in slower glucose uptake and clearance than fish fed with FO diet. Nevertheless, dietary L-carnitine supplementation up-regulated the expression of gluconeogenesis-related genes, including glucose-6-phosphatase and phosphoenolpyruvate carboxykinase in the hepatopancreas of R. lagowskii under both dietary lipid sources. In conclusion, a higher dietary n6 PUFA resulted in lipid deposition, decreased serum lipid parameters, and limited serum glucose utilization of R. lagowskii. While the regulatory effect of L-carnitine on lipid metabolism and glucose utilization of R. lagowskii varies with dietary lipid sources and tissues.

РАЗНООБРАЗИЕ И ДИНАМИКА РЫБНЫХ СООБЩЕСТВ В БАССЕЙНАХ ГОРНЫХ ПРИТОКОВ АМУРА

Between 1975 and 2021 the diversity of fish communities of mountain rivers was studied in seven areas of the river Amur drainage: “Onon”, “Upper Zeya”, “Upper Bureya”, “Upper Amgun”, “Lower Amgun”, “Khingan”, “Lower Amur and Ussuri”. In these areas, various reaches of typical mountain watercourses were surveyed: 1) upper reaches (24), 2) “middle” (17) and 3) “lower” (10); 9 small mountain tributaries of lowland rivers – Amur and Ussuri, 5 mountain lakes and 6 floodplain reservoirs. According to the results of the research, 6 main types of communities were identified, including river ones: 1) upper reaches, 2) “middle” parts, 3) “lower” parts, 4) small mountain tributaries of large lowland rivers. Lake communities are represented by two main types of communities: 5) mountain lakes and 6) floodplain water bodies. In river communities, 30 fish species and one lamprey species were found; river communities are dominated by Barbatula toni, Cottus szanaga, Brachymystax tumensis, species of the genus Thymallus, as well as Rhynchocypris lagowskii and Phoxinus phoxinus. Upper reaches communities include from 4 to 12–13 species. Barbatula toni, Cottus szanaga, Brachymystax tumensis, and species of the Thymallus dominate here. In the communities of the middle parts of the rivers, there are from 7 to 17 species. Up to 23 species and one lamprey species are found in the lower parts. In the upper reaches and middle sections of the rivers, the composition of the community changes during the year as a result of seasonal migrations. In communities of mountain lakes 6 species of fish were found; three species are most common: Barbatula toni, Cottus szanaga, Brachymystax tumensis. 8 species inhabit floodplain water bodies, dominated by Rhynchocypris percnurus, Perccottus glenii, Misgurnus mohoity. The specificity of the region's coenotic diversity is determined by its position in the Amur basin, the presence or absence of mountain and floodplain lakes, as well as geomorphological and paleogeographic features.

Dietary supplementation of two indigenous Bacillus spp on the intestinal morphology, intestinal immune barrier and intestinal microbial diversity of Rhynchocypris lagowskii.

This study evaluated the effects of dietary administration of two indigenous Bacillus (A: basal control diet; B: 0.15g/kg of Bacillus subtilis; C: 0.1g/kg of Bacillus subtilis and 0.05g/kg of Bacillus licheniformis; D: 0.05g/kg of Bacillus subtilis and 0.1g/kg of Bacillus licheniformis; E: 0.15g/kg of Bacillus licheniformis) on the digestive enzyme activities, intestinal morphology, intestinal immune and barrier-related genes relative expression levels, and intestinal flora of Rhynchocypris lagowskii. The results showed that the fold height, lamina propria width, and muscle layer thickness of midgut and hindgut in group C were significantly higher than that of group A (P < 0.05). The activities of protease, amylase, and lipase in group C were significantly higher than those of group A (P < 0.05). The relative expression levels of IL-1β and IL-8 in the intestine of group C were significantly downregulated, and the relative expression levels of IL-10 and TGF-β were significantly upregulated (P < 0.05). The relative expression levels of Claudin-2 in group A significantly increased and the relative expression levels of Claudin-4 in group A significantly reduced compared with other groups (P < 0.05). The relative expression levels of ZO-1 in groups C and D were significantly higher than those of other groups (P < 0.05). The Bacillus in the intestine of group C has the highest relative abundance among all groups. Overall, it can generally be concluded that dietary supplementation of indigenous Bacillus subtilis and Bacillus licheniformis (group C) can improve the intestinal morphology, digestion, and absorption enzyme activities, enhance intestinal mucosal immunity and barrier function, and maintain the intestinal microbial balance of R. lagowskii.

Taurine can improve intestinal function and integrity in juvenile Rhynchocypris lagowskii Dybowski fed high-dose glycinin

The present study evaluated the protective effect and the regulatory mechanism of taurine on growth inhibition and intestinal damage induced by glycinin in juvenile Rhynchocypris lagowskii Dybowski. The control diets had no glycinin and taurine, the glycinin diets contained only 80 g/kg glycinin, and the glycinin + taurine diets contained 80 g/kg glycinin+10 g/kg taurine. Juvenile Rhynchocypris lagowskii Dybowski (4.65 ± 0.03 g/tail) were respectively fed with these 3 diets for 8 weeks. The results showed that glycinin significantly decreased the final body weight, weight gain rate, specific growth rate, protein efficiency rate, feed efficiency rate and feeding rate of fish compared with the control group (P < 0.05). While taurine supplementation improved the growth performance and feed efficiency, but final body weight, weight gain rate, specific growth rate of the glycinin + taurine group were still significantly lower than the control group (P < 0.05). Compared with the glycinin group, taurine supplementation significantly increased whole-body and muscle crude protein content, and hepatopancreas and intestinal protease activities (P < 0.05). Distal intestinal villous dysplasia and mucosal damage, and increased intestinal mucosal permeability were observed in the glycinin group, while taurine supplementation alleviated these adverse effects. Usefully, taurine supplementation could also partially restore the impaired immune function and antioxidant capacity of fish fed glycinin diets. Compared with the glycinin group, taurine supplementation down-regulated pro-inflammatory cytokines TNF‐α and IL-1β mRNA levels, and up-regulated anti-inflammatory cytokines IL-10 and TGF-β mRNA levels. Furthermore, taurine partially reversed the reduction of antioxidant genes Nrf2、HO-1, CAT and GPx mRNA levels in distal intestine induced by glycinin. Concluded, 80 g/kg glycinin led to intestinal damage, digestive dysfunction and increased intestinal mucosal permeability in juvenile Rhynchocypris lagowskii Dybowski, and these adverse effects were ultimately manifested in growth inhibition. But taurine supplementation could partially mitigate the negative effects induced by glycinin.

Alleviative effect of biofloc technology (BFT) on extruded soybean meal (ESBM)-induced growth inhibition and intestinal barrier dysfunction in Rhynchocypris lagowskii

This study evaluated the alleviative effect of bioflocs technology (BFT) on intestinal morphology, permeability, digestive function, immune function, antioxidant capacity and microbiota of Rhynchocypris lagowskii sensitized by extruded soybean meal (ESBM). In a 2 × 2 factorial design, R. lagowskii (6.40 ± 0.01 g) was randomly divided into 4 groups, which contains two culture modes (traditional mode and biofloc mode) and two levels of dietary ESBM (0% and 68%). At the end of the experiment (8 weeks), the results showed that the growth performance of R. lagowskii was significantly increased by BFT, but significantly decreased by feeding diets with 68% ESBM (P < 0.05). Culture mode significantly affected intestinal growth indexes, morphology, the levels of tight junction protein mRNA, the activities of digestive enzymes, immune function, inflammation response and antioxidant capacity in proximal intestines (PI), mid intestines (MI) and distal intestines (DI) (P < 0.05). These indexes (except fold height, lamina propria width, the levels of tight junction protein mRNA, the activities of protease, AKP and LZM, the levels of inflammation related mRNA, the levels of T-SOD and PC, the levels of Nrf2, Keap1, HO-1 and Maf mRNA in PI, the activities of CAT in MI, the activities of lipase and amylase in intestines) were also significantly affected the levels of dietary ESBM (P < 0.05). Intestinal permeability (DAO, 5-HT, ET-1 and D-LA) were only significantly affected by the levels of dietary ESBM (P < 0.05). In addition, the interaction between culture mode and the levels of dietary ESBM was observed for muscular layer thickness and T-AOC in PI, fold height, ZO-1, NF-κB and Nrf2 in MI, Claudin-2, IL-1β, TGF-β, T-AOC, Nrf2, HO-1 and Maf in DI (P < 0.05). Results of intestinal microbiota showed that relative abundance of Amaricoccus, Aquitalea, Chelatococcus and Nakamurella were significantly affected by culture mode, the levels of ESBM in diets and their interaction (P < 0.05). Therefore, this study indicated that intestinal morphology, permeability, digestive function, immune function, antioxidant capacity and microbiota in R. lagowskii could be affected by ESBM and alleviated by BFT.

Inhibitory effect of probiotic Bacillus spp. isolated from the digestive tract of Rhynchocypris Lagowskii on the adhesion of common pathogenic bacteria in the intestinal model

Diseases of fish caused by pathogenic bacteria are an important constraint on aquaculture production. Antibiotics have been widely used to control infectious diseases, but this has led to the emergence of drug-resistant bacteria and affected human health. In this context, probiotics are used as an alternative to antibiotics for the prevention and control of diseases in aquaculture. The aim of this study was to obtain probiotic candidate strains of Bacillus spp. from the gut of Rhynchocypris Lagowskii. Strains were screened by enzyme-producing ability, antagonism assay and antibiotic susceptibility. The safety of the strains to host fish has also been established. The isolated Bacillus licheniformis (LSG1-1) and Bacillus subtilis (LSG2-1) were characterized and performed well in tolerance experiments. In addition, LSG1-1 and LSG2-1 were detected to have higher self-aggregation ability and surface hydrophobicity. In the in vitro adhesion model, LSG1-1 and LSG2-1 showed good adhesion ability and had obvious adhesion inhibitory effect on three pathogens of Aeromonas. Based on the characteristics observed so far, Bacillus licheniformis LSG1-1 and Bacillus subtilis LSG2-1 could form potential probiotic candidates in the digestive tract of R. lagowskii to help combat diseases in aquaculture.

The effect of adding Bacillus amyloliquefaciens LSG2-8 in diets on the growth, immune function, antioxidant capacity, and disease resistance of Rhynchocypris lagowskii

The purpose of this study was to investigate the effect of Bacillus amyloliquefaciens LSG2-8 on the growth performance, immune function, antioxidant capacity, and disease resistance of Rhynchocypris lagowskii. Fish were fed with the feed containing five levels such as 0, 1.0 × 106, 1.0 × 107, 1.0 × 108, and 1.0 × 109 CFU/g of the B. amyloliquefaciens LSG2-8 for 56 days. After 56 days of feeding, twenty four fish were randomly selected to test various growth, immune and antioxidant parameters. Ten fish were challenged with Aeromonas hydrophila for 14 days; the mortality rate was recorded 14 days after infection. The results showed that B. amyloliquefaciens LSG2-8 could significantly increase the growth parameters of R. lagowskii's, such as final body weight, weight gain rate, specific growth rate, and feed efficiency (p < 0.05). Further examination revealed the activity of antioxidant enzymes, Nrf-2 mRNA, and Keap-1 mRNA gene expression in the intestine and liver, and the serum immune index of R. lagowskii in the 1.0 × 108 CFU/g were all significantly higher compared to the other groups. Furthermore, fish fed a diet supplemented with B. amyloliquefaciens LSG2-8 had a significantly lower (p < 0.05) post-challenge mortality rate than the control fish. In summary, the research results showed that B. amyloliquefaciens LSG2-8 could improve the growth performance, immune function, antioxidant capacity, and disease resistance of R. lagowskii and be used in aquaculture.

A comparative study on the effects of supplemental L-carnitine on fatty acids composition, energy status and related genes expression in Cyprinus carpio var. Jian and Rhynchocypris lagowskii (Dybowski, 1869)

This study was to compare study on the effects of supplemental L-carnitine on fatty acids composition, energy status and related genes expression in Cyprinus carpio var. Jian and Rhynchocypris lagowskii. Different concentrations of L-carnitine were added to the basal diets of two species of fish, in which Cyprinus carpio were supplemented with 0, 50 (LC), 200 (AC) and 800 (HC) mg/kg, and Rhynchocypris lagowskii were supplemented at 0, 200 (LC), 400 (AC) and 800 (HC) mg/kg, respectively, for 8 weeks. Results showed that in liver of AC group on C. carpio, the changes of HUFA and ∑DHA+EPA showed a significant downward trend, while the changes of PUFA, EFA and ∑n3 + n6 showed an upward trend. The above trend in liver of the AC group on R. lagowskii was opposite to C. carpio. With the exception of HUFA, the changes of fatty acids of AC group in muscles of the two fish were completely different. The content of ATP and AMP in liver and muscle in AC and HC groups of two fish species showed a decreasing trend, while the change trend of ADP content was opposite. AMP/ATP ratio in liver and muscle showed a trend of first increasing and then decreasing in the treatment groups of two fish species. The relative gene expression levels of AMPKα1, AMPKα2, ACC2 and CPT-I of liver and muscle in treatment groups of C. carpio showed a decreasing trend, while these values showed an opposite trend in liver of R. lagowskii. Consequently, the different fish species may be the main reason that affects the regulation of fatty acid metabolism by exogenous L-carnitine. In addition, AMPK, acting as an energy receptor is a key effector in regulation of fatty acids metabolism by L-carnitine. Further study of AMPK function in fatty acids metabolism of fish is thus warranted.

The phylogeographical pattern of the Amur minnow Rhynchocypris lagowskii (Cypriniformes: Cyprinidae) in the Qinling Mountains.

In this study, the phylogeographical pattern of the Amur minnow (Rhynchocypris lagowskii) widely distributed in the cold freshwaters of the Qinling Mountains was examined. A total of 464 specimens from 48 localities were sequenced at a 540‐bp region of the mitochondrial cytochrome b (Cytb) gene, and 69 haplotypes were obtained. The mean ratio of the number of synonymous and nonsynonymous substitutions per site (dN/dS) was 0.028 and indicated purifying selection. Haplotype diversity (h) and nucleotide diversity (π) of natural populations of R. lagowskii varied widely between distinct localities. Phylogenetic trees based on Bayesian inference (BI), maximum likelihood (ML), and maximum parsimony (MP) methods, and network analysis showed five well‐differentiated lineages, but these did not completely correspond to localities and geographic distribution. Meanwhile, analysis of molecular variances (AMOVA) indicated the highest proportion of genetic variation was attributed to the differentiation between populations rather than by our defined lineages. In addition, there was no significant correlation between the pairwise Fst values and geographic distance (p > .05). Based on the molecular clock calibration, the time to the most recent common ancestor (TMRCA) was estimated to have emerged from the Late Miocene to the Early Pleistocene. Finally, the results of demographic history based on the neutrality test, mismatch distribution, and Bayesian skyline plot (BSP) analyses showed that collectively, the populations were stable during the Pleistocene while one lineage (lineage E) probably underwent a slight contraction during the Middle Pleistocene and a rapid expansion from the Middle to the Late Pleistocene. Therefore, the study suggests the current phylogeographical pattern of R. lagowskii was likely shaped by geological events that led to vicariance followed by dispersal and secondary contact, river capture, and climatic oscillation during the Late Miocene to the Early Pleistocene in the Qinling Mountains.

Effects of Dietary Bacillus velezensis LSG2-5 on Growth, Immunity, Antioxidant Capacity, and Disease Resistance of Amur minnow (Rhynchocypris lagowskii Dybowski)

The study was aimed at investigating the effects of Bacillus velezensis LSG2-5 isolated from host’s intestinal tract on growth performance, immune response, antioxidant capacity, and disease resistance of Amur minnow (Rhynchocypris lagowskii Dybowski). 535 fish were divided into 5 groups with 3 replicates per group. Diets containing different doses (0, 106, 107, 108, and 109 CFU/g, respectively) of B. velezensis LSG2-5 were used to feed fish ( 9.95 ± 0.05 g) for 56 days. Results showed that compared with control, weight gain rate and specific growth rate of fish were significantly increased by dietary 107-109 CFU/g B. velezensis ( p &lt; .05 ). While for the feed conversion ratio, all treatment groups were significantly decreased ( p &lt; .05 ). In serum, the contents of lysozyme and immunoglobulin M were significantly increased by dietary 106-109 CFU/g B. velezensis ( p &lt; .05 ); the activities of component 3, component 4, and alkaline phosphatase were significantly increased by dietary 108 CFU/g B. velezensis ( p &lt; .05 ). The activities of catalase, glutathione peroxidase, total antioxidant capacity, and superoxide dismutase in hepatopancreas were significantly increased by dietary 108-109 CFU/g B. velezensis ( p &lt; .05 ). The activities of catalase, glutathione, glutathione peroxidase, total antioxidant capacity, and superoxide dismutase in the intestinal tract of 108 CFU/g group were significantly increased ( p &lt; .05 ). However, malondialdehyde levels in the hepatopancreas and intestines were significantly decreased by dietary 107-108 CFU/g B. velezensis ( p &lt; .05 ). Dietary 107-109 CFU/g B. velezensis significantly upregulated catalase, glutathione peroxidase, and copper/zinc superoxide dismutase mRNA levels ( p &lt; .05 ). The levels of transforming growth factor β and interleukin-10 mRNA in the hepatopancreas of fish fed with B. velezensis of 108 CFU/g were significantly increased ( p &lt; .05 ), and these in the intestinal tract of 106-109 CFU/g groups were upregulated ( p &lt; .05 ). Feeding dietary 107-108 CFU/g B. velezensis significantly downregulated interleukin-8, interleukin-1β, and tumour necrosis factor α mRNA levels in hepatopancreas and intestines ( p &lt; .05 ). After 56 days of feeding, 225 fish ( 23.20 ± 0.59 g) were challenged with Aeromonas hydrophila (108 CFU/g), and survival rates were recorded for the next 14 days. Meanwhile, the serum immune parameters of fish were determined. Results showed that compared with control, the survival rates of the treatment groups were significantly increased ( p &lt; .05 ). Lysozyme, component 3, component 4, immunoglobulin M, acid phosphatase, and alkaline phosphatase levels in serum by dietary106-109 CFU/g B. velezensis showed significant promoting effects ( p &lt; .05 ). In conclusion, dietary 107-109 CFU/g B. velezensis boosts the growth, immunity, antioxidant capacity, and against A. hydrophila infection of Amur minnow. Regression analysis suggested that the optimal dose of B. velezensis LSG2-5 in the Amur minnow diet was 5.00 × 10 8 CFU/g.

Evaluating the probiotic potential and adhesion characteristics of Bacillus spp. isolated from the intestine of Rhynchocypris lagowskii Dybowski

Evaluating the probiotic potential and adhesion characteristics of Bacillus spp. isolated from the intestine of Rhynchocypris lagowskii Dybowski

Effects of L‐carnitine supplementation on growth performance, histomorphology, antioxidant and immune function of Rhynchocypris lagowskii fed dietary fish oil replaced with corn oil

The effects of L-carnitine (LC) and dietary lipid on the growth and health of farmed fish are still conflicting. This study aimed to explore the effects of LC supplementation and dietary fish oil replacement by corn oil on growth performance, antioxidant, immune function and histomorphology of Rhynchocypris Lagowskii. Six diets were evaluated as follows: dietary fish oil as 50% and 100% replacement by corn oil, and differing in LC supplementation (0 and 400 mg/kg), were tested in R. Lagowskii for 8 weeks. The highest weight gain rate, specific growth rate and feed efficiency were observed in mix oil diets with LC. The diet with LC significantly increased the total antioxidant capacity level, total superoxide dismutase, alkaline phosphatase, lysozyme activities and immunoglobulin M, complement levels in liver and intestine compared with corn oil diet (p < 0.05). Moreover, the diet with LC significantly up-regulated the nuclear factor E2-related factor 2 (p < 0.05), and significantly down-regulated the interleukin-1-beta and tumour necrosis factor-alpha expression in liver and intestine compared with corn oil diet (p < 0.05). In conclusion, LC supplementation improved the weakening of growth performance, antioxidant capacity, immune function and tissue health caused by R. lagowskii intake of corn oil diets.

Биология рыб среднего течения реки Киренги

Kirenga River is the large (746 km long) right tributary of upper part of Lena River. River headwaters situated relatively close to west coast of Lake Baikal among the high peaks of the Baikal Ridge at 1470 m a.s.l. Fishes were collected from the Kirenga’s middle reaches during the investigations of biota of Tukolon’ nature protected territory along the 25 km section of riverbed (starting from approx. 375 km upstream from the mouth) in June 2013, June and September 2014, Oktober 2015 and April 2016. According to available data the ichthyofauna at this river section consists of 20 species in 11 families: Far Eastern brook lamprey Lethenteron reissneri, dace Leuciscus leuciscus baicalensis, roach Rutilus rutilus, Czekanowski's minnow Rhynchocypris czekanowskii, Amur minnow Rhynchocypris lagowskii, Eurasian minnow Phoxinus phoxinus, loach Cobitis melanoleuca, Siberian stone loach Barbatula toni, Northern pike Esox luceus, whitefish Coregonus pidschian, tugun Coregonus tugun, roundfish Prosopium cylindraceum, Baikal-Lena grayling Thymallus baicalolenensis, taimen Hucho taimen, lenok Brachymystax lenok, burbot Lota lota, sculpin (spotted sculpin, alpine bullhead) Cottus cf. poecilopus, Siberian sculpin Cottus sibiricus, ruff Gymnocephalus cernuus, perch Perca fluviatilis. Lamprey, burbot and sculpin in our findings were reported from guts of other piscivorous fich species but tugun and Czekanowski's minnow were not registered. Lenok and Baikal-Lena grayling are still most numerous in the river. Low abundance is characteristic to lamprey, loach, Siberian stone loach, burbot, sculpin and Siberian sculpin. Recent growth features in most species are generally similar with the ones for fishes from Kirenga’s low reaches and main course of Upper Lena. Their ages of maturation mostly coincides with other large streams in East Siberia.