Development and characterization of a fibroblastic‐like cell line from caudal fin of the red‐line torpedo,Puntius denisonii (Day) (Teleostei: Cyprinidae)

A fibroblastic‐like cell line was established from the ornamental fish, red‐line torpedo (Puntius denisonii). The red‐line torpedo fin (RTF) cell line is being maintained in Leibovitz's L‐15 medium supplemented with 10% fetal bovine serum (FBS) for over 1 year at 28 °C on a continuous basis in normal atmosphere. The growth rate of RTF cells increased as the FBS proportion increased from 5% to 20% at 28 °C with optimum growth at the concentrations of 10% FBS. The morphology of RTF cell was predominantly fibroblastic like. Propagation of these cell lines was serum dependent, with a low plating efficiency (<15%). Karyotyping analysis of RTF cells at the 25th passage indicated that the modal chromosome number was 2n=50. The cell line was cryopreserved in liquid nitrogen at ?196 °C and could be recovered from storage after 6 months with good cell viability. Polymerase chain reaction amplification of a fragment of two mitochondrial genes, 16S rRNA and CO1, confirmed the identity of these cell lines with those reported from this animal species, confirming that the cell lines originated from P. denisonii. The bacterial extracellular products from Vibrio cholerae MTCC3904 and Aeromonas hydrophila were found to be toxic to RTF. The cell lines were not susceptible to viral nervous necrosis virus, a marine fish virus.     

Responses of rainbow trout intestinal epithelial cells to different kinds of nutritional deprivation

In order to develop an in vitro system to study the cell biology of starvation in the fish intestine, rainbow trout intestinal epithelial cells were subjected to three kinds of nutrient deprivation and evaluated for 7 days. The RTgutGC cell line was grown into monolayers in Leibovitz’s basal medium supplemented with fetal bovine serum (L15/FBS) and then subjected to deprivation of serum (L15); of serum, amino acids, and vitamin (L15/ex); and of all nutrients (L15/salts). After 7 days of nutrient deprivation, the cells remained attached to the plastic surface as monolayers but changes were seen in shape, with the cells becoming more polygonal, actin and α-tubulin cytoskeleton organization, and in tight junction protein-1 (ZO-1) localization. Two barrier functions, transepithelial electrical resistance (TEER) and Lucifer Yellow (LY) retention, were impaired by nutrient deprivation. In L15/FBS, cells rapidly healed a gap or wound in the monolayer. In L15 and L15/ex, some cells moved into the gap, but after 7 days, the wound remained unhealed, whereas in L15/salts, cells did not even migrate into the gap. Upon nutrient replenishment (L15/FBS) after 7 days in L15, L15/ex, or L15/salts, cells proliferated again and healed a wound. After 7 days of nutrient deprivation, monolayers were successfully passaged with trypsin and cells in L15/FBS grew to again form monolayers. Therefore, rainbow trout intestinal epithelial cells survived starvation, but barrier and wound healing functions were impaired.     

Establishment and characterization of a kidney cell line from kelp grouper <Emphasis Type="Italic">Epinephelus moara</Emphasis>

A novel cell line, Epinephelus moara kidney cell line (EMK), was established from kidneys of kelp grouper E. moara. Cells were cultured at 24 °C in Leibovitz’s L-15 medium (L15) supplemented with antibiotics, basic fibroblast growth factor (bFGF), foetal bovine serum (FBS) and 2-mercaptoethanol (2-ME). EMK cells, fibroblastic in morphology, proliferated to 100% confluency in 3–4 days and were subcultured for over 50 passages. The cells could grow from 18 to 30 °C, with optimal growth at 24 °C. Chromosome analysis indicated that the modal chromosome number was 48 in the cells at passage 42. Green fluorescent signals could be observed in EMK cells when the cells were transfected with pEGFP-N3 plasmid. Moreover, a significant cytopathic effect (CPE) was observed in the cells after infection with Singapore grouper iridovirus (SGIV) or nervous necrosis virus (NNV), and viral replication was confirmed by quantitative real-time PCR (qPCR). These results suggested the potential of the EMK cell line for studies of transgene and pathogenesis of SGIV and NNV.     

Development of two cell culture systems from Asian seabass Lates calcarifer (Bloch)

Two new cell culture systems namely epitheloid cells of Lates (LCE) and fibroblastic cells of Lates (LCF) have been developed from fry and fingerling of the economically important brackishwater fish Lates calcarifer. Primary cultures were initiated by explant technique using caudal fin of fingerling and whole body tissue of the fry. The nutritional requirements and the growth pattern in response to different culture environment were similar for the two cell cultures. The culture medium used was Leibovitz‐15 supplemented with 20% fetal bovine serum (FBS) and 1% fish serum. The LCE comprised of epithelioid cells and LCF cells were fibroblastic. With a split ratio of 1:2, the confluency of cells was attained in 8–10 days at an incubation temperature of 28°C. The cells were found to grow well in a wide range of temperature (24–32°C) and stable at 20 and 36°C. The growth rate of LCF and LCE cells increased proportionately with the concentration of FBS from 5% to 20%. A decrease of serum level to 10% after eight subcultures produced no apparent change in cell morphology and growth rate. The viability of cells was found to be 70% when revived after a month of storage in liquid nitrogen (?196°C).     

Establishment,characterization of a new cell line from heart of half smooth tongue sole (<Emphasis Type="Italic">Cynoglossus semilaevis</Emphasis>)

A new cell line was established from the heart of a cultured marine fish, half smooth tongue sole (Cynoglossus semilaevis), designated as CSH (Cynoglossus semilaevis heart cell line). The CSH cells grow over 400 days in minimum essential medium (MEM) supplemented with 10% fetal bovine serum (FBS) and 2 ng/ml basic fibroblast growth factor (bFGF). The suitable temperature for the cell growth was 24–30°C with the optimum growth at 24°C and a reduced growth at 12 and 30°C. FBS and bFGF concentration were the two important components for CSH cells proliferation. Twenty percent FBS in the medium was found to be the optimum concentration and bFGF promoted the growth of CSH cells. The double time of the cells at 24°C was determined to 73.39 h. Chromosome analysis revealed that 44% of the cells maintained a normal diploid chromosome number (2n = 42) in the CSH cells at Passage 58. The fluorescent signals were observed in CSH after the cells were transfected with green fluorescent protein (GFP) reporter plasmids. CSH cells showed the cytopathic effect (CPE) after infection with lymphosystis disease virus (LCDV). Moreover, the LCDV particles can be observed in the cytoplasm of virus-infected cells by electron microscopy, and a segment of MCP gene for major capsid protein of LCDV was found by PCR amplification DNA of virus-infected cells.     

Establishment and characterization of a heart-derived cell line from goldfish (<Emphasis Type="Italic">Carassius auratus</Emphasis>)

The goldfish Carassius auratus, a freshwater fish in the family Cyprinidae, was one of the earliest fish to be domesticated for ornamental purposes. A cell line was established from goldfish heart (GH) tissue to create a biological monitoring tool for viral diseases. The GH cell line was optimally maintained at 25 °C in M199 medium supplemented with 10–20% fetal bovine serum. A chromosomal analysis indicated that the cell line remained diploid, with a mean chromosomal count of 100. In viral inoculation assays, significant cytopathic effects (CPEs) were caused by epizootic hematopoietic necrosis virus (EHNV), Andrias davidianus iridovirus (ADIV), and Bohle iridovirus (BIV) infections in the fish cells and the viral titers (average value) of EHNV, ADIV, and BIV in GH cells reached 10^5.0, 10^4.5, and 10^5.0 TCID₅₀/0.1 mL, respectively, within 7 days. However, no CPE was observed in the cells infected with viral hemorrhagic septicemia virus (VHSV), infectious hematopoietic necrosis virus (IHNV), spring viremia of carp virus (SVCV), infectious pancreatic necrosis virus (IPNV), channel catfish virus (CCV), or grass carp reovirus (GCRV). These results suggest that the GH cell line is a valuable tool for studying viral pathogenesis.     

Cryopreservation of male and female gonial cells by vitrification in the critically endangered cyprinid honmoroko <Emphasis Type="Italic">Gnathopogon caerulescens</Emphasis>

We investigated the feasibility of cryopreservation of spermatogonia and oogonia in the critically endangered cyprinid honmoroko Gnathopogon caerulescens using slow-cooling (freezing) and rapid-cooling (vitrification) methods. Initially, we examined the testicular cell toxicities and glass-forming properties of the five cryoprotectants: ethylene glycol (EG), glycerol (GC), dimethyl sulfoxide (DMSO), propylene glycol (PG), and 1,3-butylene glycol (BG), and we determined cryoprotectant concentrations that are suitable for freezing and vitrification solutions, respectively. Subsequently, we prepared the freezing solutions of EG, GC, DMSO, PG, and BG at 3, 2, 3, 2, and 2 M and vitrification solutions at 7, 6, 5, 5, and 4 M, respectively. Following the cryopreservation of the testicular cells mainly containing early-stage spermatogenic cells (e.g., spermatogonia and primary spermatocytes), cells were cultured for 7 days and immunochemically stained against germ cell marker protein Vasa. Areas occupied by Vasa-positive cells indicated that vitrification led to better survival of germ cells than the freezing method, and the best result was obtained with 5 M PG, about 50% recovery of germ cells following vitrification. In the case of ovarian cells containing oogonia and stage I, II, and IIIa oocytes, vitrification with 5 M DMSO resulted the best survival of oogonia, with equivalent cell numbers to those cultured without vitrification. The present data suggest that male and female gonial cells of the endangered species G. caerulescens can be efficiently cryopreserved using suitable cryoprotectants for spermatogonia and oogonia, respectively.     

Establishment and characterization of a fin cell line from blunt snout bream, Megalobrama amblycephala

This study established and characterized a new cell line (MAF) from the fin of blunt snout bream (Megalobrama amblycephala), a freshwater fish cultivated in China. MAF cells proliferated well in medium 199 supplemented with 10 % fetal bovine serum at 28 °C and have been subcultured more than 95 times in almost a year. MAF cells were revived at 90–95 % viability after 3–6 months of storage in liquid nitrogen. Karyotyping indicated that the modal chromosome number of MAF cells was 48. The MAF cell line consisted predominantly of fibroblastic and epithelial-like cells from M. amblycephala, which was confirmed by immunofluorescence and mitochondrial 12s rRNA sequencing. Viral susceptibility tests showed that MAF cells were susceptible to infection by snakehead rhabdovirus, spring viremia carp virus, and channel catfish virus, which was demonstrated by the presence of cytopathic effect, high viral titers, and PCR products. Bacterial cytotoxicity studies showed that extracellular products from Aeromonas hydrophila were toxic to MAF cells. Cu²⁺ was also cytotoxic to MAF cells, and the 24-h IC₅₀ value was 144.48 μmol/l. When MAF cells were transfected with pEGFP-N1 plasmid, bright fluorescent signals were observed, and the transfection efficiency reached up to 5 %. These results suggest that the MAF cell line may provide a valuable tool for studying virus pathogenesis, as well as cytotoxicity testing and genetic manipulation studies.     

Effects of variation in dietary contents of selenium and vitamin E on growth and physiological and haematological responses of yellowtail kingfish,Seriola lalandi

The effects of dietary selenium (Se) and vitamin E and their interaction in the nutrition of yellowtail kingfish, Seriola lalandi, were investigated. Six dietary treatments were prepared in a 3 × 2 factorial arrangement (not supplemented or supplemented with Se at 1 or 2 mg kg^?1 × supplemented with vitamin E at 40 or 180 mg kg^?1). A group of fish in triplicate were fed one of the six experimental diets for 6 weeks, and their growth performance, haematological and immune responses were measured. The results revealed positively interactive effects between dietary Se and vitamin E in yellowtail kingfish. Se significantly increased weight gain of fish fed diets low in vitamin E, but not high in vitamin E. Simultaneous supplementation of both micronutrients resulted in significant increase in serum bactericidal activity. There was no significant effect of Se or vitamin E on survival, feed intake, feed conversion ratio, haematocrit, white blood cell counts and fillet proximate composition. However, Se and vitamin E contents in fillets were significantly responsive to dietary Se and vitamin E, respectively. The supplemental level of Se at 2 mg kg^?1 significantly increased red blood cell counts and haemoglobin concentrations, while lysozyme activity in skin mucus was significantly stimulated by vitamin E. The findings of Se and vitamin E supplementation in this study can be applied to improve growth and health indices of yellowtail kingfish.     

Effect of prebiotic konjac mannanoligosaccharide on growth performances,intestinal microflora,and digestive enzyme activities in yellow catfish,Pelteobagrus fulvidraco

In the present study, konjac mannanoligosaccharide (KMOS) was evaluated as a prebiotic in yellow catfish. The fish were fed with diets containing KMOS in four concentrations: 0 g kg^?1 (C), 1.0 g kg^?1 (KM1), 2.0 g kg^?1 (KM2), and 3.0 g kg^?1 (KM3) for 49 days, respectively. Another group fed with diets containing 3.0 g kg^?1 yeast cell wall mannanoligosaccharide (MOS) (M3) was set as positive control. The results indicated that fish receiving the diets supplemented with KMOS or MOS showed higher relative gain rate (RGR), specific growth rate (SGR), and lower feed conversion ratio (FCR) with significantly differences (P < 0.05) than those fed with the basal diets. Moreover, fish receiving the diets with 2.0 g kg^?1 KMOS inclusion showed higher RGR, SGR, and lower FCR (P < 0.05) than that feeding the diets supplemented with 3.0 g kg^?1 MOS. The quantities of Bifidobacterium spp. were significantly increased (P < 0.05). Meanwhile, Escherichia coli and Aeromonas spp. were significantly reduced (P < 0.05) in the fish-feeding diets with 2.0 g kg^?1 KMOS supplement. Compared with the control group, the significantly enhancement of protease and amylase activity (P < 0.05) in intestine and pancreas was observed in fish fed with diets containing KMOS or MOS. Collectively, an optimum level of KMOS inclusion in diets could modulate intestinal microflora, induce digestive enzyme activity, and improve the growth performance of yellow catfish significantly.     

Establishment and characterization of a continuous cell line (GF-1) derived from grouper, Epinephelus coioides (Hamilton): a cell line susceptible to grouper nervous necrosis virus (GNNV)

A new continuous cell line (GF-1) was established and characterized. The GF-1 cell line, derived from the fin tissue of a grouper, Epinephelus coioides (Hamilton), was maintained in L15 medium containing 5% foetal bovine serum (FBS) at 28 °C, and has been subcultured more than 160 times since 1995. The majority of GF-1 cells are fibroblast-like, together with some epithelioid cells. Spontaneous transformation of GF-1 cells occurred during subculture 50 to subculture 80, and led to an increase of plating efficiency, less requirement of FBS and de novo susceptibility to grouper nervous necrosis virus (GNNV). Cytopathic effects (CPEs) could be observed in GF-1 cells 3–5 days post-infection with pancreatic necrosis virus (IPNV), hard clam reovirus (HCRV), eel herpes virus Formosa (EHVF) and GNNV. In addition, abundant GNNV particles were found in the cytoplasm of GNNV-infected GF-1 cells using electron microscopy and nucleic acids of GNNV virus were detected by polymerase chain reaction in the culture medium of GNNV-infected cells after CPE appeared. The experimental results indicated that GF-1 can effectively proliferate fish nodavirus and is a promising tool for studying fish nodavirus.     

The influence of feeding diets containing wheat gluten supplemented with dipeptides or free amino acids on structure and development of the skeletal muscle of carp (Cyprinus carpio)

A 28-day feeding trial was conducted to evaluate the influence of feeding diets containing plant protein wheat gluten supplemented with dipeptides or free amino acids on structure and development of the skeletal muscles of carp (Cyprinus carpio). Common carp fingerlings (1 month old) having an of average weight of 0.07 ± 0.02 g and total length of 17.79 ± 1.79 mm were fed three formulated diets—wheat gluten protein-based diets supplemented with Lys–Gly dipeptide (PP), free lysine and glycine (AA), control diet without lysine supplemented (CON)—and two other diets: restrictive diet—frozen zooplankton (Z) and commercial diet Aglo Norse (AN). After 28 days of experimental feeding, statistically significant higher survival was observed among fish fed AN and Z diets (99.5 ± 1.0 %; P ≤ 0.05). The feeding AN diet has had also a positive influence on weight and growth rate as well as on development and growth of skeletal muscles. Furthermore, carps fed AN diet had the largest area of red and white muscle as compared with the other feeding groups, and the differences were statistically significant (P ≤ 0.05). The increase in the number of proliferating cells (proliferating cell nuclear antigen) was observed on the last day of the experiment among carps fed PP, AA and CON. Moreover, fish fed PP significantly had the greatest number of MyoD- and myogenin-positive nucleus (P ≤ 0.05). Among the experimental diets based on wheat gluten, a positive impact on structure and development of muscles has been observed in carps fed PP diet.     

Hemato-immunological responses of Heros severus fed diets supplemented with different levels of Dunaliella salina

In this study, the effects of oral administration of different levels of Dunaliella salina (a natural β-carotene source) on growth parameters, immunological and hematological indices, as well as skin carotenoids, of Heros severus were investigated. One hundred and eighty H. severus weighing 27 ± 0.5 g were divided randomly into four groups in triplicate (15 fish in each replicate). Groups 1–4 received food supplemented with 0, 50, 100 and 200 mg kg^?1 D. salina powder, respectively. After 6 weeks, the growth parameters were compared among the groups. Blood samples were taken from each group, and hematological parameters including red blood cell count (RBC), white blood cell count (WBC), hematocrit (PCV), hemoglobin (Hb) and immunological indices (serum and mucus lysozyme and bactericidal activity, resistance against Aeromonas hydrophila infection) as well as carotenoid content of skin were evaluated. Results showed that some growth indices increased significantly in fish fed with 100 and 200 mg kg^?1 D. salina-supplemented food (P < 0.05). Although serum lysozyme activity was increased in fish fed with food supplemented with 100 and 200 mg kg^?1 D. salina (P < 0.05), no significant change was observed in serum and mucus bactericidal activity and mucus lysozyme activity among the groups (P > 0.05). Most of the hematological parameters such as WBC, RBC, PCV and Hb significantly increased in D. salina-treated fish compared with controls (P < 0.05). Mortality induced after challenge with A. hydrophila in 200 mg kg^?1 D. salina-treated fish was 36.67 %, which significantly decreased compared with control (P < 0.05). Skin carotenoid content in all D. salina treatments was statistically higher than that of control (P < 0.05). Conclusively, D. salina as a food additive can affect positively the growth, immunological and hematological parameters of H. severus.     

The efficacy of three mycotoxin adsorbents to alleviate aflatoxin B1-induced toxicity in Oreochromis niloticus

Aflatoxicosis, toxicity of aflatoxin, is of great concern in aquaculture. This study was conducted to assess the efficacies of three adsorbents, a hydrated sodium calcium aluminosilicates (HSCAS), Saccharomyces cerevisiae (S.C.) and an esterified glucomannan (EGM), against feed contaminated with contained 200 μg/kg (ppb) aflatoxin B₁ (AFB₁). A total of 240 Nile tilapia fingerlings, Oreochromis niloticus (15 ± 2 g), were randomly divided into eight experimental groups (30 fish per group) with three replicates. Group T₁ represented the negative control fed on a basal diet, and T₂ was the positive control group fed on a basal diet supplemented with 200 ppb AFB₁. Groups T₃, T₄ and T₅ were fed the AFB₁-contaminated diet (200 ppb) supplemented with 0.5 % HSCAS, 0.25 % S.C or 0.25 % EGM, respectively. Groups T₆, T₇ and T₈ were fed a basal diet supplemented with 0.5 % HSCAS, 0.25 % S.C or 0.25 % EGM, respectively. The reduction in AFB₁-bioavailability was judged by toxin residues in fish musculature throughout the study beginning at the second week of exposure. AFB₁ reduced the survivability, total weight gain, average daily gain and specific growth rate, evident as early as the second week of exposure. The total erythrocyte count, hemoglobin content and total leukocyte count were significantly decreased after AFB₁ exposure for 6, 8 and 10 weeks, respectively. Prolonged administration of AFB₁ led to significant increases in serum alanine transaminase, aspartate transaminase and creatinine activity, and produced significant decreases in plasma proteins, including serum globulin. The specific immune response was assessed by an agglutinating antibody titer after immunization of the fish with an Aeromonas hydrophila vaccine. The antibody titer and relative level of protection of fish challenged with Aeromonas hydrophila were reduced throughout the period of examination in AFB₁-exposed fish. Supplementation with HSCAS, S.C. or EGM significantly improved growth performance, blood parameters and immune status; in addition, these groups showed decreased AFB₁ residues in fish musculature when compared with AFB₁-treated fish. HSCAS effectively reduced AFB₁ toxicity, whereas S.C. and EGM were less efficacious.     

Galactooligosaccharide and a combination of yeast and β-glucan supplements enhance growth and improve intestinal condition in striped catfish <Emphasis Type="Italic">Pangasianodon hypophthalmus</Emphasis> fed soybean meal diets

The effects of galactooligosaccharide (GOS) and a combination of yeast and β-glucan (YβG) supplementation of dietary soybean meal (SBM) on the growth and digestive performance of striped catfish Pangasianodon hypophthalmus were evaluated. Four isonitrogenous (30% protein) and isocaloric (19 MJ/kg diet) diets were formulated to contain 100% fish meal (FM) protein, 55% FM protein/45% SBM protein, FM-SBM supplemented with 1% GOS, and a combination of 1% yeast and 0.1% β-glucan, respectively. Each diet was fed for 12 weeks to three groups of 30 striped catfish fingerlings (average weight 16.45?±?0.07 g) maintained in circular fiberglass tanks (600 l). Growth, feed utilization, and muscle protein composition of fish improved significantly after supplementation with either GOS or YβG compared to the unsupplemented SBM diet, but were similar to those of fish fed the FM diet. Nutrient digestibility, digestive enzyme activities, villi and microvilli length were significantly increased in fish fed the supplemented SBM diets. The gut microbiota ranking profile showed that supplementing the SBM diet with YβG and GOS gave a ranking of Verrucomicrobia, Spirochaetes, Bacteriodetes, and Actinobacteria phyla similar to that of the FM diet. Thus, diet containing 45% protein from soybean supplemented with either GOS or YβG can be recommended to improve the growth and digestive performance of striped catfish.     

Two iridovirus-susceptible cell lines established from kidney and liver of grouper, Epinephelus awoara (Temminck & Schlegel), and partial characterization of grouper iridovirus

Two iridovirus-susceptible cell lines were established and characterized from grouper Epinephelus awoara kidney and liver tissues. These cell lines have been designated GK and GL, respectively. The cells multiplied well in Leibovitz's L-15 medium, supplemented with 10% foetal bovine serum, at temperatures between 20 and 32 °C, and have been subcultured more than 120 times, becoming continuous cell lines. The cell lines consist of a heterogeneous mixture of fibroblastic and epithelial cells. The viability of cells, stored frozen in liquid nitrogen (−196 °C), was 95% after 1 year. Chromosome morphologies of GK and GL cells were homogeneous. Both cell lines were susceptible to grouper iridovirus, and yielded high titres of up to 108 TCID50 mL⁻¹. In addition, both cell lines effectively replicated the virus, which could be purified to homogeneity by cesium chloride gradient centrifugation. Electron microscopy studies showed that purified virus particles were 170±10 nm in diameter, and were hexagonal in shape. Virus-infected cells showed an abundance of virus particles inside the cytoplasm. These results show that the GK and GL cell lines effectively replicate grouper iridovirus, and can be used as a tool for studying fish iridoviruses.     

Effects of dietary supplementation with green tea waste on growth,digestive enzyme and lipid metabolism of juvenile hybrid tilapia, <Emphasis Type="Italic">Oreochromis niloticus</Emphasis> × <Emphasis Type="Italic">O. aureus</Emphasis>

An 8-week feeding trial was conducted to evaluate the effects of dietary supplementation with green tea waste (GTW) on growth, digestive enzyme and lipid metabolism of juvenile hybrid tilapia, Oreochromis niloticus × O. aureus. The fish (initial mean body weight, 12.63 ± 0.75 g) were fed five experimental diets that included 0 (control), 0.8, 1.6, 3.2 or 6.4 % of GTW in triplicate aquaria, twice daily. Growth performance, plasma metabolites content and liver and intestine digestive enzyme activities were determined. Fish accepted well all experimental diets during the trial, and no mortality was observed. The weight gain increased (P < 0.05) with the increase in GTW inclusion level up to 1.6 %, after which it decreased, but no significant differences between the control and high level (3.2 or 6.4 % of GTW) groups were observed. Moreover, fish fed on diets containing 0.8 and 1.6 % GTW had lower feed conversion ratio (FCR, 1.75 and 1.73, respectively) and had better protein deposition (higher protein efficiency ratio, PER, 1.73 and 1.71, respectively), compared to other treatments. No differences among groups were observed in whole body and dorsal muscle composition with the exception of lipid content which was lower in fish fed 6.4 % GTW diets, compared to other treatments. Lipase activities in liver or intestine were higher in fish fed GTW-supplemented diets with the exception of intestine lipase activities, which was unaffected, compared to the control. Similarly, liver lipoprotein lipase activities were also increased in fish fed diets supplemented a medium dose of GTW (1.6 or 3.2 %), compared to other treatments. However, intestine amylase activities were decreased in fish fed diets containing a high dose of GTW (3.2 and 6.4 %); while the liver amylase activities were unaffected by the GTW supplementation. Blood chemistry parameters were affected by GTW inclusion, except the values of triglycerides, which was unaffected. The values of total cholesterol, HDL cholesterol and LDL cholesterol increased with increasing GTW inclusion level up to 3.2 %, after which the values decreased. These results indicate that diets supplemented with appropriate concentration of GTW (from 0.8 to 1.6 %) may potentially serve as an effective functional food and additive for tilapia to improve growth performance, digestion efficacy and fat metabolism.