The Annual Reproductive Cycle, Proximate Composition, Fatty Acid and Amino Acid Content of Pacific Oyster, Crassostrea gigas (Magallana gigas), in Gadeok-do, Korea.

Environmental factors impact oyster growth, condition, and gonadal development, which is linked to gamete characteristics observed through histology. The reproductive cycle of bivalves is related to energy storage and utilization. Therefore, in this study, the year-round growth change and gonadal development of oysters were observed using histological analysis, and the biochemical composition changes were confirmed. The oysters used in this study are being nurtured in Gadeok-do, and 40 oysters were randomly sampled monthly from March 2021 to February 2022. Result of histological analysis of gonads, oysters were showed early development from December to February, late development from March and April, mature and ripe from May to July, spawned from August to October, and spent from November to December. Condition index values of oysters decreased in summer and autumn and increased again when entered the spent after spawning. The protein content of oysters was high in May, the maturity period, and the lipid content decreased during the spawning period. In addition, EPA and DHA, the major fatty acids of oysters, were low during the spawning period and high during the maturation period. As a result, this study suggested a close relationship between changes in oyster growth, biochemical composition, and the reproductive cycle.

Evaluation of Yeast Hydrolysate in a Low-Fishmeal Diet for Whiteleg Shrimp (Litopenaeus vannamei).

An eight-week feeding trial was performed to evaluate the effects of yeast hydrolysate (YH) supplementation in a low-fishmeal diet on the growth, immune responses, intestinal histology and disease resistance of whiteleg shrimp (Litopenaeus vannamei). Five experimental diets were produced by supplementing YH at 0 (CON), 0.5 (YH0.5), 1 (YH1), 2 (YH2) and 4 (YH4) % to a basal diet containing 10% fishmeal and compared with a positive control with 25% fishmeal (FM25). Shrimp with an initial average weight of 0.43 ± 0.005 g (mean ± SD) were stocked in 18 tanks and fed the experimental diets (38% protein and 8% lipid) four times a day. Results showed that shrimp fed the FM25 diet exhibited significantly higher final body weight, weight gain, specific growth rate and protein efficiency ratio than those fed CON, YH0.5, YH1 and YH2 diets (p < 0.05). However, there were no significant differences between shrimp fed the YH4 and FM25 diets (p > 0.05). In addition, there were no significant differences in whole-body proximate composition, hemolymph biochemical parameters and non-specific immune responses among treatments. Intestinal villi length and muscular layer thickness of shrimp fed the YH4 and FM25 diets were significantly higher than the other groups. At the end of the bacterial (Vibrio parahaemolyticus) challenge test, shrimp fed YH4 and FM25 diets showed a significantly higher survival rate than those of shrimp fed CON, YH0.5 and YH1 (p < 0.05). These results suggest that supplementing 4% YH in diet containing 10% fishmeal could beneficially influence growth, intestinal morphology and disease resistance of whiteleg shrimp.

Comparison of growth performance, non-specific immunity, and intestinal microbiota of olive flounder (Paralichthys olivaceus) fed with extruded pellet and moist pellet diets under field conditions in South Korea.

A 6-month feeding trial was conducted to compare the effects of extruded pellet (EP) and moist pellet (MP) feed on the growth performance, non-specific immunity, and intestinal microbiota of olive flounder. A total of 60,000 fish with an average weight of 70.8 ± 6.4 g were divided into two groups and fed with one of two experimental diets. At the end of a 6-month feeding trial, the weight gain and specific growth rate of the fish fed with the MP diets were significantly higher than those of fish fed with EP (P < 0.05). However, the EP group exhibited a lower feed conversion rate than the MP group, meaning that the EP diet was more cost-effective. Whole-body proximate compositions and non-specific immune responses (superoxide dismutase, myeloperoxidase, and lysozyme activity) were not significantly different between the two groups. There were no significant differences in the α-diversity of the intestinal bacterial community of the two groups. However, the composition of microorganisms at the phylum to genus level was different between the groups. The EP group was rich in Actinobacteria, Corynebacterium, Bacillus, and Lactobacillus, whereas the MP group was dominated by Proteobacteria, Vibrio, and Edwardsiella. Collectively, the MP diet increased growth performance and pathogen concentration in the gut; whereas EP improved feed conversion and beneficial Bacillus and Lactobacillus proportion in the intestinal microbial community.

Effects of Decreasing Fishmeal as Main Source of Protein on Growth, Digestive Physiology, and Gut Microbiota of Olive Flounder (Paralichthys olivaceus).

In olive flounder (Paralichthys olivaceus), growth performance, expression of growth-related factors, digestive physiology, and gut microbiota were assessed under farm conditions in the fish fed diets with low levels of fishmeal. Four experimental diets were prepared, FM70 [control (CON), 70% fishmeal], FM45 (45% fishmeal), FM35A (35% fishmeal), and FM35B (35% fishmeal + insect meal), and fed to the fish for five months. The CON-fed fish had the highest plasma GH, but IGF-1 and hepatic IGF-1 mRNA expression of the olive flounder fed diets with low-fishmeal levels did not significantly differ among diets. The intestinal villus length, muscular thickness, and the number of goblet cells were statistically similar, and ocular examination of hepatopancreas showed no discernable difference in all experimental diets. The chymotrypsin content of FM35B-fed fish is significantly lower, but trypsin and lipase contents are similar. The diversity of gut microbiota did not differ among groups, although the FM35B group had a higher composition of Firmicutes. Thus, a diet with reduced fishmeal content and several alternative protein sources can be used as feed ingredients in feed formulation for olive flounder reared under typical aquaculture farm conditions.

Dementia Prevalence in Older Adults: Variation by Race/Ethnicity and Immigrant Status.

OBJECTIVE: To examine differences in prevalence and risk factors of dementia by race/ethnicity and immigrant status using a nationally representative sample of Medicare beneficiaries. METHODS: This was a cross-sectional study performed in the United States among non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic, and other Medicare beneficiaries from round 1 of the National Health and Aging Trends Study (N = 7,609). The authors used log-binomial regression analyses to investigate risk factors and interactions between race/ethnicity and immigrant status and dementia. Stratified log-binomial regression analyses by race/ethnicity were used to interpret the results of interaction effects of immigrant status found in these surveys. Analyses were conducted in three forms: probable dementia versus possible and no dementia, probable and possible dementia versus no dementia; and probable dementia versus no dementia. RESULTS: Consistent with previous studies, U.S.-born NHBs have a higher prevalence of dementia than U.S.-born whites, Hispanics, and others. Immigrant status moderated the relationship between race/ethnicity and dementia. NHWs, Hispanics, and other immigrants had a higher prevalence of dementia compared with their U.S.-born counterparts. However, U.S.-born NHBs had a higher prevalence of dementia compared with NHB immigrants. Results were consistent across the three forms of analysis. Greater age predicted higher dementia across the four racial/ethnic groups. CONCLUSION: Immigrant status may have complex effects on dementia risk. Selection factors affecting immigration-varied health and educational systems in diverse countries of origin, acculturative stress, and validity of dementia assessment across diverse groups-deserve further attention.

Cultural Adaptation of a Dyadic Intervention for Korean Couples Coping with Alzheimer's Disease.

OBJECTIVES: The Couples Life Story Approach (CLSA) was recently developed in the U.S. for older couples dealing with dementia to improve their quality of life. The purpose of this article is to describe how the CLSA was adapted to be culturally appropriate for older Korean couples and to discuss cultural themes that emerged during the implementation process. METHODS: The intervention was adapted using the Cultural Adaptation Process Model. The revised materials were implemented on 56 Korean couples. A multiple case study method was used to analyze the clinical data. RESULTS: Four cultural themes were identified: (1) dealing with negative memories in early years of marriage; (2) communication styles and patterns; (3) ways to incorporate difficult life events into the Life Story Book; and (4) complex dynamics of heirarchy in the relationship between older couples and the interventionist. With each theme, case examples are described that illustrate relevant issues. CONCLUSIONS: Cultural adaptation can be conducted systematically to improve the delivery of the CLSA for different populations. CLINICAL IMPLICATIONS: Cliniocians working with older Korean couples affected by dementia should consider cultural uniqueness in a life-story approach.

Dexamethasone treatment inhibits VEGF production via suppression of STAT3 in a head and neck cancer cell line.

Glucocorticoids (GCs) modulate the synthesis of many pro-inflammatory cytokines and influence multiple transduction pathways. GCs negatively or positively influence the transcription factors of their target genes. All of these transcription signals are closely connected to cancer survival or death. We investigated the action of dexamethasone (DEX) on head and neck cancer cell lines. When SNU-1041 and SNU-1076 were treated with DEX, the cell lines showed different patterns of responses. DEX inhibition of cell growth depended on concentration in SNU-1041, but not in SNU-1076. Furthermore, DEX suppressed vascular endothelial growth factor (VEGF) secretion from SNU-1041, but not from SNU-1076. We explored the mechanism that explains these distinct differences. After DEX treatment, the differences of NF-kappaB (p65), glucocorticoid receptor and p-AKT were not observed between the cell lines. However, phospho-signal transducer and activator of transcription 3 (STAT3) decreased in SNU-1041 only. Moreover, STAT3 inhibition using si-RNA suppressed VEGF secretion. When STAT3 was overexpressed after DEX treatment, the level of VEGF in the culture media was restored. Taken together, we suggest that p-STAT3 can be a mediating factor which regulates VEGF secretion in the DEX treatment. Because the relationship between the three molecules DEX, STAT3 and VEGF is scarcely known, our findings clarified one of the signaling pathways of DEX, which is often used in clinical conditions.