Aranya Ponpornpisit

Modulation of intestinal morphology and immunity in nile tilapia (Oreochromis niloticus) by Lactobacillus rhamnosus GG.

The use of lactic acid bacteria from human origins as a potential probiotic supplementation in aquaculture feed is now widely accepted. Here, we examined some of the properties and mechanisms of the action of Lactobacillus rhamnosus GG, originating from humans, on growth performance, gut mucosal immunity and humoral and cellular immune response in tilapia (Oreochromis niloticus). The results suggested that supplementation of L. rhamnosus gave an advantage in promoting the intestinal structure and the mucosal immunity of tilapia. Probiotic fish had a greater villous height in all parts of the intestines and, significantly, in the proximal and middle part. The population of intraepithelial lymphocytes was significantly higher in the probiotic group than in the control group in all parts of the intestines. The population of acidophilic granulocyte in the probiotic group was significantly higher at the proximal and distal parts when compared with the control group. The higher serum complement activity as well as the enhanced phagocytosis and killing ability of the head kidney leukocytes in the probiotic supplemented fish corresponded with the higher level of TNF alpha and IL-1 gene expression, suggesting that the induction of IL-1 and TNF alpha cytokines by L. rhamnosus served as an important regulator of gut associated immune systems.

The analysis of expressed genes in head kidney of common carp Cyprinus carpio L. stimulated with peptidoglycan

We analyzed expressed genes in kidney of common carp Cyprinus carpio L. stimulated with peptidoglycan (PG). The results of single-pass sequencing of expressed sequence tags (ESTs) from 150 clones (AU279235-AU279382, AB086061, AU298711) from kidney cDNA are presented. Sequences of the cDNA clones were compared with sequences in the GenBank database. Fifty-five clones (36.7%) appeared to be completely unknown and are likely to represent newly described genes, whereas 95 clones (63.3%) were identified based on matches to sequences in the database. The clones contain several ribosomal proteins, cytochrome oxidase subunits and tumor-related proteins. Immune-related cDNAs identified from the kidney were bactericidal permeability-increasing protein/LPS binding protein (BPI/LBP), β-thymosin, CC-chemokine, CD18, cyclophilin, Fc gamma receptor (FcγR), granulocyte colony stimulating factor receptor (G-CSFR), heat shock 70-kDa protein 4 (HSP70-4), Ig lambda, Ig heavy chain, Ig light chain, integrin β2-α, Mx, interleukin-1β, lysozyme C, MHC class II associated invariant chain and tumor necrosis factor α-induced protein. Semiquantitative expression analysis showed that transcription levels of BPI/LBP, G-CSFR and HSP70-4 was increased by PG stimulation.

The Pathological Effects of Melamine and Cyanuric Acid in the Diet of Walking Catfish (Clarius batrachus)

The toxicity of melamine and its analogue in man and animals has been reported widely. The aim of the present study was to examine the pathological effects of feeding melamine and cyanuric acid, separately or in combination, to walking catfish (Clarius batrachus). The catfish developed darkening of the skin as early as 3 days post feeding. Melamine-related crystals were distributed multifocally throughout the liver, kidney, heart, spleen and corpuscle of Stannius of fish fed melamine and cyanuric acid in combination. Oil red O staining and electron microscopy revealed that the melamine-related crystals had structure resembling that of plastic polymer crystals. Elevations in the serum concentrations of alanine transaminase, aspartate transaminase, creatinine and uric acid were related to the crystal-associated granulomatous inflammation in the liver and kidney of affected fish. None of the catfish died during the 2-week experiment. Melamine and cyanuric acid are therefore systemically toxic to fish in addition to causing renal crystal formation and renal damage as seen in man and animals. The finding of extrarenal crystals implies that the metabolism and biotransformation of these toxic compounds should be further investigated in aquatic animals.

Short-term Exposure of Nile Tilapia (Oreochromis niloticus) to Mercury Histopathological Changes, Mercury Bioaccumulation, and Protective Role of Metallothioneins in Different Exposure Routes

To investigate effects of short-term mercury (Hg) exposure in tilapia (Oreochromis niloticus) including histopathological changes, Hg bioaccumulation, and protective role of metallothionein (MT) in different exposure routes, adult tilapias were intraperitoneally injected, orally intubated, or semistatically exposed to 0.5, 1, 2, 5 µg/g mercuric chloride. Histopathology, autometallography (AMG), inductive coupled plasma–atomic emission spectrometry (ICP-AES), and MT immunohistochemistry were determined at 0, 3, 6, 9, 12, and 15 days postexposure. Microscopic lesions were observed in the kidney, hepatopancreas, spleen, and intestine. AMG positive grains were found in renal tubule epithelium, melanomacrophage centers (MMCs), and intestinal epithelium of treated tilapias. Hg concentrations measured by ICP-AES in abdominal visceral organs were significantly higher than in other organs. All exposure routes caused lesions of increasing severity and Hg accumulations in a dose-dependent manner. Semistatic groups produced the highest intensity of lesions, AMG positive staining, as well as total Hg concentrations. Positive MT expression in renal tubule epithelium, pancreatic acini, and splenic MMCs was observed only in semistatic groups. The semistatic exposure route demonstrated the most significant microscopic lesions, Hg bioaccumulation, and MT expression.