Approach to Epidemiological Mechanism of Infection or Colonization of Egg-Laying Chicken Farms by <i>Salmonella enterica</i>Serovar Enteritidis (SE) Becoming the Main Source of Contamination in Food Poisoning (Review)

Salmonella enterica serovar Enteritidis (SE)-induced diarrhea in humans is the typical non-typhoid diarrhea. It develops acutely or subacutely and may be fatal. This SE infectious disease suddenly became a major public health issue worldwide in the 1980s. The main causative food material of SE food poisoning is chicken eggs, and many outbreaks of food poisoning caused by chicken eggs occurred throughout the world. SE epidemics occurred in layer farms, and this was the main cause of SE-induced food poisoning in humans. The major subject of our epidemiological study described in this report is why SE-contaminated eggs became the main causative food. In this study, we focused on difference of molecular expression for farm-isolated SEs. That is because recent studies have demonstrated that O-antigen enlargement may be related to pathogenicity in mice as well as 22-kDa polypeptide-expression (SEp22). We have discovered that many SE strains isolated from chicken farms do not express SEp22, and a deficiency or decreased level of cellular antigen 0-12 in SE strains isolated from chicken farms was clarified in a report. Additionally, SEp22 was deficient in SE strains passaged through chickens, whereas SEp22 was expressed at a high level in SE strains passaged through mice. These findings suggest that SE infection and retention more effectively occur in layer farms than in other animal maintenance environments, which may be a basis of the epidemiological hypothesis to explain the high-levelproduction of SE-contaminated eggs (the presence of mice may be the basis of the retention of SE infection in layer farms, and this may also be the mechanism causing the high-level production of SE-contaminated eggs).

Molecular Characterization and Expression Analysis of SKIV Infection of Interferon-Induced Protein with Tetratricopeptide Repeats 1(IFIT1) in Epinephelus lanceolatus

Interferon-induced protein with tetratricopeptide repeats 1(IFIT1), also known as interferon-induced protein 56(IFI56) or Interferon-stimulated protein 56(ISG56), was originally identified as a protein induced upon treatment with interferon and inhibited by viral replication and translational initiation. In this study, Epinephelus lanceolatus IFIT1(ELIFIT1) gene was cloned for the first time. The complete cDNA of El IFIT1 gene includes 2921 nucleotides, and encodes a 437-amino acid(AA) protein. The putative ELIFIT1 protein has 9 TRP domains and is highly similar with IFIT1 proteins in other teleosts. In healthy fish, ELIFIT1 gene was highly expressed in the blood, which indicate its specific function in the peripheral immune system. Its expression was also observed in various immunity-related tissues including spleen, intestine, and kidney, Inducted with spotted knifejaw iridovirus(SKIV), ELIFIT1 gene expression was upregulated in the spleen, kidney, and liver 24 h after induction and reached its peak at 72 h, indicating that ELIFIT1 may play an important role in antivirus. These findings contribute to the understanding of the antiviral regulation of ELIFIT1 gene in teleost.

Effects of dietary supplementation of Lactobacillus plantarum and Bacillus subtilis on growth performance,survival,immune response,antioxidant capacity and digestive enzyme activity in olive flounder(Paralichthys olivaceus)

In present study,a 10-month feeding trial was carried out to investigate effects of dietary Lactobacillus plantarum and Bacillus subtilis supplementation singly on growth performance,innate immune response,antioxidant capacity and digestive enzyme activity of olive flounder under a commercial production environment.Two experimental groups fed basal diet with supplementation of L.plantarum(5.0×107 CFU/g diet)and B.subtilis(1.0×108 CFU/g diet)respectively,and control group fed with basal diet without probiotics supplement.At harvest,serum immune parameters,liver antioxidant indices and digestive enzyme activities in liver,stomach and intestines were measured.Fish fed with B.subtilis supplemented diet showed the highest growth rate which was significantly higher than L.plantarum supplemented group(P<0.05)which was also significantly higher than control group(P<0.05).Survival rate were significantly elevated by feeding diet with L.plantarum supplementation(P<0.05),while the improvement was not significant for B.subtilis supplemented diet compared to control group.All the studied immune parameters in serum were substantially enhanced in both experimental groups.Similar results were observed for the antioxidant capacity in liver.Besides,the activities of digestive enzymes increased substantially in both experimental groups compared to control group and the detected improvement in dietary B.subtilis supplemented group were all higher than in L.plantarum supplemented group,though not all the improvements were significant.In summary,the separate supplementation of B.subtilis and L.plantarum in diet is more beneficial for growth performance and healthy status respectively.Hence,in olive flounder aquaculture,favorable effects of compounded supplementation of L.plantarum and B.subtilis are expected.

Estimationof genetic parameters for juvenile growth performance traits in oliveflounder(Paralichthys olivaceus)

The aim of this study was to evaluate genetic parameters of growth traits for improving selective breeding in olive flounder(Paralichthys olivaceus).A total of 82 full-sib families from 2 year-classes with complete pedigree information were used to estimate heritabilities and genetic/phenotypic correlations for 4 growth performance traits(body weight BW,total length TL,body height BH and condition factor K)based on uni-trait and multi-trait linear mixed models,respectively.Data were analyzed by the restricted maximum likelihood(REML)method.The heritabilities of BW,TL and BH were 0.81,0.70 and 0.61,which are relatively high,however,heritability for K is low(0.11).For all growth traits,the common full-sib effects(c^(2))were at a low to moderate level(0.14–0.20);the maternal effects(m^(2))of the traits(except K)were also detected(0.15–0.19).The phenotypic and genetic correlations among BW,TL and BH were highly positive(0.70–0.91),however,the correlations between K and the other 3 traits was low or negligible(−0.22–0.26).According to our results,these traits(except K)could be selected and enhanced simultaneously.In addition,direct selection based on TL or BH,which is an easily measurable trait,will be more favorable than selection on BW.Moreover,our results indicated that growth parameters estimated in the juvenile stage could be used as a predictor of growth performance at later growth stages.

Estimation of heritabilities of disease resistance to Edwardsiella tarda and genetic correlations between resistance and growth traits in Chinese tongue sole (Cynoglossus semilaevis)

Chinese tongue sole(Cynoglossus semilaevis)is an important marine flatfish which is widely cultured in coastal areas in China.Infectious bacterial diseases such as Edwardsiella tarda imposed serious threats to this species.A potential strategy to prevent this disease is to select resistance strains.The aim of the present work was to estimate the genetic variation of disease resistance to E.tarda and to evaluate the genetic correlations between resistance traits and growth traits.Three types of models were fitted by using different trait definitions(binary,continuous and categorical).After a 9-day challenge test,the overall survival was 75.4%(ranging from 6.4%to 100%in families),and at test day 6,the overall survival was 50.7%.We set test day 6 and 9 as cut-off point times respectively.The heritabilities of survival traits were ranging from 0.10 to 0.36.Considerably higher heritability values were obtained at day 6 than at day 9,regardless of which model or trait definition used(except Trait 2 in LIN).The genetic correlations between disease resistance traits and growth traits(i.e.body weight and total length)were low and not significant from zero(−0.12–0.24).There is a substantial re-ranking of families when defined resistance as categorical and continuous traits compared to binary trait.These results confirm the existence of genetic variation for resistance against E.tarda and weak genetic correlations indicate that joint genetic improvement of E.tarda resistance and growth is scarcely available.