Jiazhang Chen

Effects of dietary resveratrol supplementation on hepatic and serum pro-/anti-inflammatory activity in juvenile GIFT tilapia, Oreochromis niloticus

&NA; Dietary resveratrol (RES) supplementation may have some pharmacological effects including anti‐inflammation. Previous studies have shown that Kupffer cell activation and apoptosis induction increases the transcription of pro‐ and anti‐inflammatory cytokines. The main purpose of this study was to investigate the pro‐ and anti‐inflammatory activities of 0.1 or 0.3 g/kg RES as a dietary supplement in juvenile freshwater tilapia (Oreochromis niloticus). The results showed that hepatic and serum immunoglobulin M (IgM) significantly decreased and increased while anti‐ and pro‐inflammatory cytokines significantly increased and decreased, respectively, in the RES‐treated groups. The expression of serum and hepatic IgM and anti‐inflammatory cytokines [interleukin (IL)‐10] and its inverse inhibitor interferon (IFN)‐&ggr; significantly increased while pro‐inflammatory cytokine transcription significantly decreased. Hematoxylin‐eosin staining and scanning electron microscopy revealed intestinal deformation, irregular goblet cells, and apoptotic cells in the 0.3 g/kg RES groups. RES (0.3 g/kg) also induced necrosis, apoptosis, reduction in Kupffer cell number, compressed sinusoids, and deformation of epidermal cells in the liver of the treated groups. In conclusion, the results of the present study show that high doses of RES were absorbed in the gut and then damaged the liver and intestinal tissue. Graphical abstract Irregular goblet cells, apoptotic cells, necrosis, apoptosis, reduction in Kupffer cell number, compressed sinusoids, and deformation of epidermal cells has been revealed in the 0.3 g/kg RES groups. Figure. No caption available. HighlightsHepatic and serum IgM significantly decreased and increased.Anti‐ and pro‐inflammatory cytokines significantly increased and decreased.Serum and hepatic igm, IL‐10 and IFN‐&ggr; significantly increased.Pro‐inflammatory cytokine transcription significantly decreased.Irregular goblet cells, apoptosis, reduction in Kupffer cell number revealed.

Responses of glutathione‐related antioxidant defense system in serum of Nile tilapia (Oreochromis niloticus) exposed to sublethal concentration of methomyl and recovery pattern

Tilapia were exposed to sublethal concentrations of 0, 0.2, 2, 20, or 200 μg/L for 30 days, and then transferred to methomyl‐free water for 18 days. GST, GPx, GR, GSH, and GSSG in tilapia serum were examined at 0, 6, 12, 18, 24, and 30 days after methomyl exposure and at 18 days after transferring to methomyl‐free water. There were no significant changes in antioxidants activities and contents in serum of tilapia exposed to 0.2 μg/L. Significant increases in GST, GR, GPx, and GSSG accompanied by a decrease in GSH were observed following methomyl exposure to 2, 20, or 200 μg/L, suggesting the presence of oxidative stress. Thus, it would appear the 0.2 μg/L methomyl might be considered the no observed adverse effect level. Recovery data showed that the effects produced by lower concentration of 20 μg/L were reversible but not at the higher 200 μg/L concentration.

Dietary supplementation with rutin has pro-/anti-inflammatory effects in the liver of juvenile GIFT tilapia, Oreochromis niloticus

ABSTRACT Dietary supplementation with rutin may have some pharmacological qualities including anti‐inflammatory effects. Kupffer cell activation resulted in increased transcription of pro‐ and anti‐inflammatory cytokines. The main purpose of this study was to investigate the pro‐ and anti‐inflammatory activities in juvenile freshwater tilapia, Oreochromis niloticus, in response to 0.1 or 0.3 g/kg dietary supplementation of rutin. Results showed that hepatic IgM, anti‐inflammatory‐cytokines, and pro‐inflammatory cytokines were significantly decreased in groups treated with high doses of rutin. Hepatic IgM and anti‐inflammatory cytokines (IL‐10 and IFN‐&ggr;) transcripts were significantly decreased, whereas the transcripts of the pro‐inflammatory cytokines, TNF&agr; and IL‐1&bgr; were significantly decreased, whereas IL‐8 was significantly increased. The number of Kupffer cells in rutin‐treated groups was significantly decreased, and scanning electron micrographs showed that rutin enriched the number of gut microvilli and secretion pits. With the phenomena of cell apoptosis occurred in the rutin groups, the present study demonstrated that optimum levels of rutin may be beneficial but excessive level may cause liver impairment, which may be absorbed by the gut and then transported to the liver. HIGHLIGHTSHepatic IgM, anti‐inflammatory and pro‐inflammatory cytokines significantly decreased.Hepatic IgM, IL‐10, IFN‐&ggr;, TNF&agr; and IL‐1&bgr; significantly decreased, whereas IL‐8 increased.The number of Kupffer cells significantly decreased.Rutin enriched the number of gut microvilli and secretion pits.

Hepatic transcriptome analysis of juvenile GIFT tilapia (Oreochromis niloticus), fed diets supplemented with different concentrations of resveratrol.

The GIFT (Genetically Improved Farmed Tilapia) tilapia, Oreochromis niloticus, is cultured widely for the production of freshwater fish in China. Streptococcosis, which is related to pathogenic infections, occurs frequently in juvenile and adult female GIFT individuals. Resveratrol (RES) has been used in feed to control these infections in freshwater tilapia. To address the effects of RES on tilapia, we used high-throughput RNA sequencing technology (RNA-Seq, HiSeq. 2500) to explore the global transcriptomic response and specific involvement of hepatic mRNA of juvenile O. niloticus fed with diets containing different concentrations of (0, 0.025, 0.05, and 0.1g/kg) RES. A total of > 24,513,018 clean reads were generated and then assembled into 23,244 unigenes. The unigenes were annotated by comparing them against non-redundant protein sequence (Nr), non-redundant nucleotide (Nt), Swiss-Prot, Pfam, Gene Ontology database (GO), Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, and 12,578 unigenes were annotated to the GO database. A total of 1444 (0.025g/kg RES), 1526 (0.05g/kg RES), and 3135 (0.1g/kg RES) genes were detected as significant differentially expressed genes (DEGs), when compared with the controls. A total of 6 (0.025 vs 0.05g/kg RES), 19 (0.025 vs 0.1g/kg RES), and 124 (0.05 vs 0.1g/kg RES) genes were detected as significant DEGs. Six genes, including dnah7x1, sox4, fam46a, hsp90a, ddit4, and nmrk2, were associated with an immune response. These findings provide information on the innate immunity of GIFT and might contribute to the development of strategies for the effective management of diseases and long-term sustainability of O. niloticus culture.

Exploration of three heterotrophic nitrifying strains from a tilapia pond for their characteristics of inorganic nitrogen use and application in aquaculture water

Three heterotrophic nitrifying bacterial strains, HLf01, HBf01 and HHf01, were isolated from a pond where genetically improved farmed tilapia (GIFT) (Oreochromis niloticus) was intensively cultured during the annual peak breeding period. Analysis of biochemical, morphological characteristics and sequences analysis of 16S rDNA identified strains HLf01 and HBf01 as Pseudomonas sp., and strain HHf01 as Acinetobacter baumannii. Further analysis of heterotrophic nitrifying medium inorganic nitrogen used showed that most of the ammonia nitrogen was removed after 48 h. Strains HBf01 and HHf01 removed 67.9% and 76.7% of the total ammonia nitrogen after 24 h, recording the mass ratio of carbon to nitrogen used as 10.6 to 1 and 11.7 to 1, respectively. Strain HLf01 used a C:N ratio of 22.7 to 1 with a total of 43.8% ammonia nitrogen removed. In denitrifying media, strains HBf01 and HHf01 may have used nitrate and nitrite as the sole nitrogen source by strain HLf01. Generally, all the three strains used nitrogen in the order ammonia > nitrite > nitrate when all the three nitrogen forms were recorded present. Although the bacterial strains consumed dissolved organic carbon, it was limited when ammonia was the main source of nitrogen compared with other forms of inorganic nitrogen. Also, the test of the three strains on aquaculture water showed similar results of efficiency of ammonia nitrogen removal with the test of inorganic nitrogen use.

Archaeal community compositions in tilapia pond systems and their influencing factors

Archaea, like the bacterial communities are gradually being realized as key players in the biogeochemical progress of water ecosystems. In this study, tilapia aquaculture ponds were used for an in-depth understanding of archaeal community compositions in water and surface sediment. Some of the main functions, as well as the communities’ response patterns, to time variations, pond differences and some physio-chemical parameters were investigated. The results revealed the dominant phylum in both the water and surface sediment, as Euryarchaeota, while, the most abundant classes were: Halobacteria and Methanomicrobia respectively. Significant differences in the archaeal community compositions in the water and surface sediment, were observed in the early stages of cultivation, which became minimal at the later stage of the GIFT tilapia cultivation. Additionally to the differences in the most abundant classes, more OTUs were observed in water samples than in surface sediment samples. The methane generation could be attributed to the large proportion of methanogens found in both pond water and in the surface sediment. Furthermore, the archaeal community compositions in water and the surface sediment were shaped mainly by temporal variations and pond differences respectively. In the pond water, the archaeal community compositions were highly co-related to the concentration changes of ammonia, sulfate and total nitrogen; while in the surface sediment, the correlation to the content changes was significant in total phosphorus. The archaeal community compositions in surface sediment should be considered as an indicator for future environmental capacity studies in aquaculture.

Gut microbiota analysis of juvenile genetically improved farmed tilapia ( Oreochromis niloticus ) by dietary supplementation of different resveratrol concentrations

ABSTRACT The genetically improved farmed tilapia (GIFT, Oreochromis niloticus) is cultured widely for production of freshwater fish in China, while streptococcosis, likely related to pathogenic infections, occurs frequently in juvenile, mother, and operated GIFT. The gut microbiota plays an important role in nutrient digestibility in animals, and resveratrol (RES) has been used in feed for different freshwater fish species. Therefore, understanding changes in the tilapia gut microbiota across different concentrations of dietary RES supplementation is extremely important. The gut microbiota population in tilapia at 45 d after supplementation with different concentrations (0, 0.025, 0.05, 0.1 g/kg) of dietary RES was assessed by 16S rDNA gene sequencing. A total of 5445 operational taxonomic units were identified from all samples, and 14 phyla and 81 families were identified from all fecal samples. The bacteria of the phylum Firmicutes were significantly enriched in the 0.025 g/kg RES group when compared with the controls. Proteobacteria, Firmicutes and Cyanobacteria were the most dominant three phyla in all samples. With the increasing concentrations, the proportion of beneficial microbial taxa (Acetobacteraceae and Methylobacteriaceae) increased, whereas the proportion of harmful microbial taxa decreased, eg. Streptococcaceae except for 0.1 g/kg RES groups. RES did not affect the richness and diversity in tilapia gut microbiota. These findings provide information on the diversity and differences in GIFT gut microbiota database, and may contribute to developing strategies for management of diseases and long‐term sustainability of O. niloticus culture. HighlightsA total of 5445 operational taxonomic units were identified.The bacteria of the phylum Firmicutes were significantly enriched in the 0.025 g/kg RES group.Proteobacteria, Firmicutes and Cyanobacteria were the most dominant three phyla in all samples.With the increasing concentrations, the proportion of beneficial microbial taxa increased, whereas the proportion of harmful microbial taxa decreased.Richness and diversity of microbiota in GIFT tilapia not changed.

Effect of methomyl on sex steroid hormone and vitellogenin levels in serum of male tilapia (Oreochromis niloticus) and recovery pattern

Tilapia were exposed to sub‐lethal concentrations of 0, 0.2, 2, 20 or 200 μg/L for 30 days, then transferred to methomyl‐free water for 18 days. E2, T, 11‐KTand VTG in serum were examined. There were no significant changes in all the parameters in serum of tilapia exposed to 0.2 μg/L and 2 μg/L methomyl compared to the control. However, 20 μg/L and 200 μg/L have the potential to disrupt the endocrine system of male tilapia, as shown by its ability to increase VTG and E2 and decrease T and 11‐KT in serum. Thus it would appear the no observed adverse effect level for sexual steroid hormones of methomyl is lower than 2 μg/L. Recovery data showed that the effects produced by 20μg/L were reversible but not at 200μg/L. Furthermore, the sensitivity of above parameters to methomyl followed the order of VTG>E2>11‐KT>T>GSI, suggesting VTG being the better biomarkers.