The effects of orally administered marine red yeast
Rhodosporidium paludigenum on growth performance and antioxidant competence of
Litopenaeus vannamei were evaluated in a six-week feeding trial. The ...shrimps were fed with three diets, including the control diet, the diet containing 1% dry yeast and the diet containing 10
8
yeasts
g
−
1
diet.
R. paludigenum supplementation caused significant increase in WG, SGR and survival rate of the shrimps as compared with the control group (p
<
0.05). No statistical differences were found in MDA content of serum and hepatopancreases. Higher T-AOC of serum and higher SOD, GPX activities of hepatopancreases from
L. vannamei were observed in the group fed with the dry yeast diet. In addition higher T-AOC, CAT, SOD, GPX activities in serum and higher SOD, GPX activities of hepatopancreases of shrimps were observed in the group fed with live yeast diet. The statistical differences were found in MDA content of muscle, and SOD activities were significantly lower in the groups fed with the live yeast diet and the dry yeast diet as compared with the control group (p
<
0.05). The results showed that the diet supplemented with
R. paludigenum could enhance the growth performance and antioxidant competence of
L. vannamei, and
R. paludigenum had the potential to be a promising probiotic.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
IgD is considered to be a recently-evolved Ig and a puzzling molecule, being previously found in all vertebrate taxa, except for birds. Although IgD likely plays an important role in vertebrate ...immune responses, the function of IgD in Nile tilapia (Oreochromis niloticus) is virtually unknown. In the present study, a membrane form of IgD (mIgD) heavy chains were cloned from the GIFT strain of Nile tilapia (designated On-mIgD). The On-mIgD heavy chain's cDNA is composed of 3347 bp with a 31 bp of 5'-UTR, 3015 bp open reading frame (ORF) and 301 bp 3'-UTR, encoding a polypeptide of 1004 amino acids (GenBank accession no: KF530821). Phylogenetic analysis revealed that On-mIgD heavy chains showed the highest similarity to Siniperca chuatsi. Quantitative real-time PCR (qRT-PCR) analysis showed that On-mIgD expression occurred predominately in head kidney, thymus, spleen, and kidney. After Streptococcus agalactiae infection, transcripts of On-mIgD increased and reached its peak at 48 h in the head kidney and thymus, and 72 h in the spleen, respectively. Taken together, these results collectively indicated that IgD could possibly have a key role to play in the immune response when bacterial infections in Nile tilapia.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
An 8-week feeding experiment was conducted to quantify the dietary methionine requirement of juvenile cobia (initial weight of 11.61
±
0.16 g, mean
±
SD) reared in indoor flow-through and aerated ...aquaria. Six amino acid test diets (44% CP and 16% lipid), using fish meal and wheat gluten as intact protein sources supplemented with crystalline amino acids, were formulated to contain graded levels of methionine (0.61%, 0.83%, 1.05%, 1.30%, 1.48% and 1.68% of dry diet, respectively) at a constant dietary cystine level of 0.67%. Each diet was randomly assigned to three aquaria. Growth performance and feed utilization were significantly influenced by the dietary methionine levels (
P
<
0.05). Maximum weight gain, specific growth rate and protein efficiency ratio occurred at 1.05% dietary methionine (
P
<
0.05). The hepatosomatic index, viscerosomatic index and condition factor were not significantly affected by dietary methionine levels (
P
>
0.05). There were no significant differences in protein, lipid, ash and moisture contents in whole body or muscle, also red blood cell count and plasma protein content for fish fed graded methionine levels of diets; however, hemoglobin, hematocrit, leukocyte, plasma glucose and triacylglycerol concentrations showed significant differences among these treatments (
P
<
0.05). Methionine concentration in plasma significantly increased with an increase of dietary methionine (
P
<
0.05). Quadratic regression analysis of specific growth rate against dietary methionine levels indicated that the optimal dietary methionine requirement for maximum growth and feed utilization of juvenile cobia is 1.19% of dry diet in the presence of 0.67% cystine (corresponding to 2.64% of dietary protein on a dry weight basis).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
An 8-week feeding trial was conducted to quantify the dietary lysine requirement of juvenile cobia with an initial average weight of 1.25 g reared in indoor flow-through and aerated aquaria. Six ...isonitrogenous and isoenergetic practical diets (44% CP and 16% lipid) containing six levels of dietary lysine ranging from 1.15 to 3.25% (dry weight) at about 0.4% increments, using fish meal and wheat gluten as sources of intact protein, supplemented with crystalline amino acids. Equal amino acid nitrogen was maintained by replacing lysine with nonessential amino acid mixture. Each diet was randomly assigned to three aquaria and was fed to apparent satiation by hand four times daily. The results indicated that there were significantly differences in growth performance and feed utilization among the treatments. Maximum weight gain, special growth rate and protein efficiency ratio occurred at 2.38% dietary lysine; but with the increase of dietary lysine from 2.38 to 3.25%, weight gain, special growth rate and protein efficiency ratio did not significantly increase. The hepatosomatic index, viscerosomatic index, condition factor, crude protein content in whole body and main composition in muscle were significantly affected by dietary lysine levels; however moisture, lipid and ash content in whole body were not significantly affected by the dietary lysine. There were significant differences in total serum protein, glucose and triacyglycerol concentrations in fish fed diets with different dietary lysine levels. Haematocrit and leukocyte count were significantly affected by dietary lysine level, but hemoglobin and red blood cell count were not significantly affected. Lysine concentration in serum was significantly increased with the increase of dietary lysine level from 1.15 to 2.38%. Broken-line analysis on the basis of special growth rate showed that the dietary lysine requirement of juvenile cobia was 2.33% of dry diet (5.30% dietary protein).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
273 bacterial strains were isolated from 20 Chinese longsnout catfish samples. The biochemical characteristics of all strains conformed to the species description of Aeromonas veronii bv. veronii on ...the basis of Vitek GNI+ card. Furthermore, 16S rDNA, gyrB and rpoD sequences of the representative strain PY50 were sequenced and showed high similarity with A. veronii bv. veronii in Genbank. Antibiotic-resistance of the representative strain PY50 was assessed by the Kirby-Bauer disk diffusion method, and the results showed it was susceptible and moderately susceptible to 13 and 4 of the 21 antimicrobial agents tested. Extracellular products of strain PY50 contained gelatinase, lecithinase, elastase, most of lipase and lipopolysaccharide. Virulence of strain PY50 and extracellular products to Chinese longsnout catfish were also tested, and LD50 were about 3.47×104 CFU per fish and 11.22 μg per fish in intraperitoneal injection respectively. This is the first report that A. veronii bv. veronii was the pathogenic agent of ulcerative syndrome in Chinese longsnout catfish. PUBLICATION ABSTRACT
Populations of marine red yeast from shrimps and the environments of shrimp culture were investigated from various areas at Zhanjiang in China. All strains were studied for the production of biomass ...and carotenoids. We isolated 88 marine red yeast strains and the average populations of marine red yeast in seawater and the water from shrimp culture ponds were 70.0 and 172.4 CFU per 100 ml water, respectively. For shrimp samples, average populations of marine red yeast from gills, intestines, and stomachs were 178.0, 15.0, and 8.0 CFU per shrimp, respectively. The isolates were grouped into nine species belonging to three genera as follows: Rhodosporidium, Rhodotorula, and Sporidiobolus. R. sphaerocarpum had the highest average biomass yield (10.3 ± 0.88 g/l), followed by S. ruineniae (10.1 g/l) and Rh. mucilaginosa (9.9 ± 1.75 g/l). R. paludigenum had the highest average carotenoid yield (2.83 ± 0.589 mg/l), followed by S. pararoseus (2.72 mg/l) and R. sphaerocarpum (2.59 ± 0.454 mg/l). The results showed that marine red yeasts were normal microbial components in the environments of shrimp culture and shrimps, and carotenoids are abundant in these marine red yeast.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Grass carp reovirus (GCRV) is a causative agent of haemorrhagic disease in grass carp that drastically affects grass carp aquaculture. Here we report a novel GCRV isolate isolated from sick grass ...carp that induces obvious cytopathic effect in CIK cells and name it as GCRV096. A large number of GCRV 096 viral particles were found in the infected CIK cells by electron microscope. The shape, size and the arrangement of this virus were similar to those of grass carp reovirus. With the primers designed according to GCRV 873 genome sequences, specific bands were amplified from sick grass carp and the infected CIK cells. The homology rates among
vp4
,
vp6
and
vp7
gene in GCRV 096 and those of some GCRV isolates were over 89%. In this study, the sequences of
vp4
,
vp6
and
vp7
were used to analyse sequence variation, phylogenetic relationships and genotypes in twenty five GCRV isolates. The results indicated these twenty five GCRV isolates should be attributed to four genotypes. And there were no obvious characteristics in the geographical distribution of GCRV genotype. The study should provide the exact foundation for developing more effective prevention strategies of grass carp haemorrhagic disease.
Vibrio alginolyticus is one of the most serious diseases in cultured marine and freshwater fish and shellfish. The absence of suitable vaccine or virulent marker can be the bottleneck to control V. ...alginolyticus infection. In this study, immunoproteomic approaches were undertaken to study the immunogenicity of the whole‐cell protein of V. alginolyticus HY9901. The whole‐cell proteins were analysed by two‐dimensional gel electrophoresis and subsequent immunoblotting using the rabbit anti‐V. alginolyticus HY9901 serum. A total of 55 immunogenic proteins were identified by immunoproteomic analysis. Of the 55 proteins, 51 are specific immunoreactive proteins and four are nonspecific immunoreactive proteins. Furthermore, outer membrane protein N (spot 2) was used as immunogens to immunize Epinephelus coioides for investigation of protective abilities and activities. The E. coioides immunized with OmpN has abilities to fight against infections caused by V. alginolyticus. The other novel immunogenic proteins may be developed as alternative antigens for further study of V. alginolyticus vaccine and diagnostics. These data show that immunoproteomics methods can be successfully applied in identifying immunogenic proteins of V. alginolyticus, which helps to search for the protective antigens in future.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The outer membrane proteins of Vibrio alginolyticus play an important role in the virulence of the bacterium and are potential candidates for vaccine development. In the present study, the ompW gene ...was cloned, expressed and purified. A DNA vaccine was constructed by inserting the ompW gene into a pcDNA plasmid. Crimson snapper Lutjanus erythropterus (Bloch) were injected intramuscularly with the recombinant plasmid pcDNA-ompW. The expression of the DNA vaccine was detected in gill, head kidney, heart, liver, spleen and injection site muscle of crimson snapper by RT-PCR 7 and 28 d post-vaccination. The ELISA results demonstrated that the DNA vaccine produced an observable antibody response in all sera of the vaccinated fish. In addition, crimson snapper immunized with the DNA vaccine showed a relative percentage survival (RPS) of 92.53%, indicating effective protection against V. alginolyticus infection.
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