Cholesterol requirement and phytosterols efficiency in semi‐purified diets of juvenile Pacific white shrimp Litopenaeus vannamei

Studies pertaining to cholesterol requirement are limited based on the levels evaluated and statistical analysis. Two trials were conducted to refine cholesterol requirement in Pacific white shrimp Litopenaeus vannamei feeds. The basal diet was supplemented with graded levels of cholesterol (ranging from 0.48 to 1.85 g/kg) in trial 1. Since the shrimp (initial weight: 0.24 g) growth response was very linear without reaching a plateau, it was not clear whether the requirement was met. Hence, a second trial was designed using eight diets designed with an increased range of cholesterol levels from 0.45 to 4.57 g/kg of diets. The shrimp (0.38 g initial weight) reached a final weight of (4.31–7.43 g) or per cent weight gain from 1,014%–1,874% (n = 4) after 6 weeks. Saturation kinetic model and broken‐line models with linear or quadratic ascending portions were used to evaluate dose–response relationships of feed efficiency (FE), thermal‐unit growth coefficient (TGC), whole‐body cholesterol (CHOL) and cholesterol deposition (CHOLD) against dietary cholesterol. The cholesterol requirement of shrimp was estimated at 1.9 (1.1–4.3) g/kg, 1.7 (1.1–3.4) g/kg, 2.5 (2.3–2.9) g/kg and 2.7 (2.4–3.1) g/kg of shrimp diet for FE, TGC, CHOL and CHOLD, respectively. Additionally, based on improved growth, the inclusion of phytosterol can serve as a partial replacement for cholesterol.     

Microbial risk assessment of livestock-integrated aquaculture and fish handling in Vietnam

Animal manure has been traditionally used to fertilize fish ponds in Vietnam. While this practice effectively reuses agricultural wastes, high concentrations of pathogenic microorganisms in animal manure raise public health concerns. Working in fish ponds and handling of contaminated fish in unhygienic manner were identified as potential factors of occupational risk. Escherichia coli occurred in numbers <10³ colony forming units (CFU)/100 mL in irrigation water and <10⁴ CFU/100 mL in fish pond water that uses animal manure. Escherichia coli on tilapia skin in numbers were <10³ CFU/100 cm in excreta-based systems and <10¹ CFU/100 cm in feed-based systems, respectively. The study identified direct use of animal manure as major contributors of the fecal contamination of pond water as well as skin of cultured fish. Estimated risks of enteric infection were 100–1000 times higher than the US Environmental Protection Agency acceptable risk. While these risk values are not likely to accurately predict infection rates in Vietnam, they indicate a potential occupational risk in the long term. Therefore, a need for risk mitigation measures was realized for health protection of future generation in agricultural communities.     

Chemical interaction between polyphenols and a cysteinyl thiol under radical oxidation conditions

Chemical interaction between polyphenols and thiols was investigated under radical oxidation conditions using a model cysteinyl thiol derivative, N-benzoylcysteine methyl ester. The radical oxidation was carried out with a stoichiometric amount of 2,2-diphenyl-1-picrylhydrazyl (DPPH), and the decreases in the amounts of polyphenols and the thiol were measured by HPLC analysis. Cross-coupling products between various polyphenols and the thiol were examined by LC-MS in reactions that showed decreases in both the polyphenols and the thiol. The LC-MS results indicated that three phenolic acid esters (methyl caffeate, methyl dihydrocaffeate, and methyl protocatechuate) and six flavonoids (kaempferol, myricetin, luteolin, morin, taxifolin, and catechin) gave corresponding thiol adducts, whereas three polyphenols (methyl ferulate, methyl sinapate, and quercetin) gave only dimers or simple oxidation products without thiol substituents. Thiol adducts of the structurally related compounds methyl caffeate and methyl dihydrocaffeate were isolated, and their chemical structures were determined by NMR analysis. The mechanism for the thiol addition was discussed on the basis of the structures of the products.     

Establishment of an Invasive Prostate Cancer Model in Transgenic Rats by Intermittent Testosterone Administration

We have established a transgenic rat for adenocarcinoma of the prostate (TRAP) model that features uniform adenocarcinoma development in prostatic lobes at high incidence within a short experimental period. However, no invasive carcinomas with reactive stroma characteristics similar to those in man were observed. We therefore have focused on a new model for invasive carcinoma of the prostate using TRAP rats. In experiment 1, male TRAP rats in groups 1 and 2 were treated with orchiectomy at day 0 of the experiment. Rats in groups 1–3 underwent testosterone propionate (TP) implantation from weeks 1 to 4 and from weeks 6 to 16. Rats in groups 1 and 3 were given 3,2’-dimethyl-4-aminobiphenyl (DMAB) after TP implantation. The rats of group 4 served as controls. In experiment 2, the rats were divided into three groups, none of which received DMAB or orchiectomy, treated with TP continuously or with the treatment withdrawn once or twice. In experiment 1, invasive adenocarcinomas with abundant collagenous stroma were found in the dorsolateral and anterior prostate, some of which showed perineural space invasion at week 16. The number of invasive carcinoma foci was most frequent in group 3. In experiment 2, invasive adenocarcinoma development in the lateral prostates was correlated with the number of TP administration/withdrawal cycles. In conclusion, our newly established rat model for invasive adenocarcinoma of the prostate could serve as a useful preclinical model for evaluating the in vivo efficacy of preventive and therapeutic agents targeting of the tumor microenvironment.     

番茄果实采后硬度变化的理化解析

在20℃、RH95%条件下对‘Saturn’番茄果实硬度变化进行了物理和化学解析。结果表明,随贮藏天数的推移贯入抵抗和压缩抵抗下降较快,多聚半乳糖醛酸酶(PG)活性和纤维素酶活性变化较大,而果胶甲酯酶(PME)活性变化较小。果肉硬度下降与半纤维素的下降和水溶性果胶(WSP)的上升有密切关系。     

Melatonin can improve viability and functional integrity of cooled and frozen/thawed rabbit spermatozoa

Melatonin is known to protect sperm against freezing-inflicted damage in different domestic species. The aim of the study was to evaluate the effect of supplementation of semen extender with melatonin on the quality and DNA integrity of cooled and frozen/thawed rabbit spermatozoa. We also investigated whether the addition of melatonin to the semen extender could improve the fertility of rabbit does artificially inseminated with frozen/thawed semen. Semen samples collected from eight rabbit bucks were pooled and then diluted in INRA-82 supplemented either with (0.5, 1.0 or 1.5 mM) or without (0.0 mM) melatonin. Diluted semen was cooled at 5°C for 24 hr. For cryopreservation and based on the first experiment's best result, semen samples were diluted in INRA-82 in the presence or absence of 1.0 mM melatonin and then frozen in 0.25 ml straws. Following cooling or thawing, sperm quality and DNA integrity were evaluated. Furthermore, the fertility of frozen/thawed semen was investigated after artificial insemination. Supplementation of semen extender with 1.0 mM melatonin improved (p < .05) motility, viability, membrane and acrosome integrities in cooled semen compared with other groups. Sperm quality and DNA integrity were higher (p < .05) in frozen/thawed semen diluted in 1.0 mM melatonin-supplemented extender than in the control group. Conception and birth rates were higher in does inseminated with 1.0 mM melatonin treated semen compared with the controls. In conclusion, supplementation of semen extender with 1.0 mM melatonin improved the quality of cooled and frozen/thawed rabbit spermatozoa. Melatonin can preserve DNA integrity and enhance the fertility of frozen/thawed rabbit spermatozoa.     

A sero-survey of subtype H3 influenza A virus infection in dogs and cats in Japan

A sero-epidemiological survey of human and equine H3 influenza A virus infections in dogs and cats using the hemagglutination inhibition (HI) and neuraminidase inhibition (NI) tests was conducted. Serum samples were collected from 582 dogs and 237 cats in Japan during the periods 2002-2008 and 1997-2008, respectively. Although no HI antibodies against equine H3 virus were detected, 9 (3.8%) from cats and 12 (2.1%) from dogs were HI-positive against human H3 virus. Only one serum each from dogs and cats was NI-positive against N2 virus. These findings suggest that although equine H3 influenza virus infections have not been prevalent in companion animals, human H3N2 influenza A virus infections have occurred in dogs and cats in recent years in Japan.     

ROS-generating mitochondrial DNA mutations can regulate tumor cell metastasis

Mutations in mitochondrial DNA (mtDNA) occur at high frequency in human tumors, but whether these mutations alter tumor cell behavior has been unclear. We used cytoplasmic hybrid (cybrid) technology to replace the endogenous mtDNA in a mouse tumor cell line that was poorly metastatic with mtDNA from a cell line that was highly metastatic, and vice versa. Using assays of metastasis in mice, we found that the recipient tumor cells acquired the metastatic potential of the transferred mtDNA. The mtDNA conferring high metastatic potential contained G13997A and 13885insC mutations in the gene encoding NADH (reduced form of nicotinamide adenine dinucleotide) dehydrogenase subunit 6 (ND6). These mutations produced a deficiency in respiratory complex I activity and were associated with overproduction of reactive oxygen species (ROS). Pretreatment of the highly metastatic tumor cells with ROS scavengers suppressed their metastatic potential in mice. These results indicate that mtDNA mutations can contribute to tumor progression by enhancing the metastatic potential of tumor cells.     

The chisan-chisho movement: Japanese local food movement and its challenges

This paper examines the increasingly popular chisan-chisho movement that has promoted the localization of food consumption in Japan since the late-1990s. Chisan-chisho emerged in the context of a perceived crisis in the Japanese food system, particularly the long-term decline of agriculture and rural community and more recent episodes of food scandals. Although initially started as a grassroots movement, many chisan-chisho initiatives are now organized by governments and farmers’ cooperatives. Acknowledging that the chisan-chisho movement has added some important resources and a conceptual framework, we nonetheless point out that chisan-chisho has been refashioned as a producer movement by government as well as the Japan Agricultural Cooperative, capitalizing on local food’s marketing appeal. Chisan-chisho to date has not been able to become a full-fledged citizen-based political mobilization nor address the issue of marginality in the food system.