Low Density Group Research Articles

Effects of stocking density during the dry period on dairy cow physiology, metabolism and behaviour.

The effects of high stocking density during the dry period on dairy cow physiology, behaviour and welfare were investigated. Holstein Friesian cows (n = 48, calving over a seven month period) were dried-off 60 ± 4 d before their expected calving date, and allocated to either high (H) or low (L) stocking density groups. Cows were housed in cubicles from dry-off to 21 d before calving and then moved to straw yards until calving. In cubicle pens, H and L cows had 0.5 vs. 1.0 feed yokes/cow and 1.0 vs. 1.5 cubicles/cow, respectively, and in straw yards, 0.3 m vs. 0.6 m linear feed-face space and 6 m2vs. 12 m2 lying space, respectively. Video observations of feeding behaviour during the 3 h after feed delivery (3 d/week) and agonistic interactions at the feed-face during peak feeding (2 d/week) were made. Daily lying proportion was measured using an accelerometer device throughout the dry period. Concentrations of faecal glucocorticoid metabolites (FGCM) at dry-off, d7 and d35 after dry-off and d21 and d7 before calving and the change in energy metabolites (glucose, NEFA, BHB) from dry-off to d7 before calving were measured. H cows were less likely to start feeding within 5 min of feed delivery and spent less time feeding compared to L cows, but they engaged in displacements more frequently and spent more time standing in the feed alley. Irrespective of the treatment groups, FGCM concentrations significantly increased from dry-off to d7 after dry-off and remained higher during the dry period. Stocking density did not affect daily lying proportion, energy metabolites during the dry period and milk yield during subsequent lactation. This study found that whilst high stocking density during the dry period increased competition at the feed-face and altered feeding behaviour, it did not affect stress responses, energy metabolism or subsequent milk yield.

A community-based study of the relationship between calcaneal bone mineral density and systemic parameters of blood glucose and lipids.

Osteoporosis (OP) is a disease characterized by decreased bone mineral density (BMD) and an increased risk of osteoporotic fractures. Nutritional factors (including glucose and fats lipids), have been implicated in OP.We hypothesized that the levels of blood glucose and lipids could be biomarkers for predicting the risk of OP. To test this hypothesis, we evaluated the potential relationship between BMD and levels of blood glucose and lipids via a community-based study in China.This was a community-based cross-section analysis, and a total of 8584 cases were investigated. The BMD of the left calcaneus was measured using an ultrasonic bone densitometer. The levels of blood glucose (fasting blood glucose [FBG], 2-h blood glucose [2hBG], and glycosylated hemoglobin [HbAlc]), and lipids (triglyceride [TG], total cholesterol [TC], low-density lipoprotein cholesterol [LDL-C], and high-density lipoprotein cholesterol [HDL-C]) were measured and analyzed.In our study population, the levels of FBG, 2hBG, HbAlc, TC, LDL-C and HDL-C were higher in the OP group than in the low bone density and the normal bone density groups, while the levels of HbAlc, TC, and LDL-C in the low bone density group were higher than those in the normal bone density group. In males, the level of blood LDL-C in the low bone density group was higher than that in the normal bone density group. In postmenopausal subjects, the levels of FBG, 2hBG and HbA1C were higher than those in the normal bone density groups, and the level of HbA1C in the low bone density group was higher than that in the normal bone density group. Pearson linear trend analysis demonstrated that BMD was positively associated with TC and LDL-C in males and negatively associated with FBG, 2hBG and HbA1C in postmenopausal females. Moreover, logistic analysis showed that BMD was correlated with TC in premenopausal females and HbA1C in postmenopausal females.OP is generally associated with abnormal levels of blood glucose and/or lipids; nevertheless, the relationship between OP and abnormal levels of blood glucose and/or lipids is complicate and different subpopulations may have different susceptibilities. Therefore, further detailed studies are warranted.

A population of high-velocity absorption-line systems residing in the Local Group

Aims. We investigated the ionisation conditions and distances of Galactic high-velocity clouds (HVCs) in the Galactic halo and beyond in the direction of the Local Group (LG) barycentre and anti-barycentre, by studying spectral data of 29 extragalactic background sources obtained with the Cosmic Origins Spectropgraph (COS) installed on the Hubble Space Telescope (HST). Methods. We model column-densities of low, intermediate, and high ions such as Si II, C II, Si III, Si VI, and C IV, and use these data to construct a set of Cloudy ionisation models. Results. In total, we found 69 high-velocity absorption components along the 29 lines of sight. The components in the direction of the LG barycentre span the entire range of studied velocities, 100 ≲ |vLSR| ≲ 400 km s−1, while those in the anti-barycentre sample have velocities up to about 300 km s−1. For 49 components, we infer the gas densities. In the direction of the LG barycentre, the gas densities exhibit a wide range from log nH = −3.96 to −2.55, while in the anti-barycentre direction the densities are systematically higher, log nH > −3.25. The barycentre absorbers can be split into two groups based on their density: a high-density group with log nH > −3.54, which can be affected by the Milky Way radiation field, and a low-density group (log nH ≤ −3.54). The latter has very low thermal pressures of P/k < 7.3 K cm−3. Conclusions. Our study shows that part of the absorbers in the LG barycentre direction trace gas at very low gas densities and thermal pressures. These properties indicate that the absorbers are located beyond the virial radius of the Milky Way. Our study also confirms results from earlier, single-sightline studies, suggesting the presence of a metal-enriched intragroup medium filling the LG near its barycentre.

Effects of stocking density on stress response, innate immune parameters, and welfare of turbot (Scophthalmus maximus)

This experiment was conducted to investigate the growth performance, stress and immune responses, and welfare of juvenile turbot (Scophthalmus maximus) under three different densities (initial density 9.3, 13.6, and 19.1 kg m−2) for 120 days in a recirculating aquaculture system. Turbot were measured every 20 days to evaluate growth biometrically and sampled every month to measure biochemical parameters and mRNA levels of some stress-related genes. No significant differences were detected in the parameters and gene expression among density groups until the final sampling, except Fulton’s condition factor, lysozyme, immunoglobulin M, and complement C3. At the end of the experiment (final density 26.11, 38.22, and 52.25 kg m−2), turbot reared in the high-density (HD) group had lower body mass increase, specific growth rate, and Fulton’s condition factor, as well as higher feed conversion ratio and coefficient of variation for weight than those reared in the low-density (LD) group (P < 0.05). Fish in the HD group had higher serum cortisol, glucose, lactate, and cholesterol levels than fish in the other groups, whereas they had lower lysozyme, immunoglobulin M, and complement C3 and C4 contents (P < 0.05). Fish reared in the HD group also had higher serum chloride and osmolality levels and higher sodium-potassium adenosine triphosphatase (Na+,K+-ATPase) activity and higher Na+,K+-ATPase gene expression levels in gills compared to the other groups (P < 0.05). The mRNA levels of cytochrome P450 1A (CYP1A) and heat-shock proteins 70 and 90 (HSP70 and HSP90) were significantly upregulated, whereas glutathione S-transferase (GST) mRNA levels were significantly downregulated in the head kidney of fish in the HD group relative to fish in the other groups at the end of this trial (P < 0.05). These results indicated that overly high stocking (~50 kg m−2) density can negatively affect the growth performance, serum biochemical parameters, osmolality levels, stress-related gene expression, and overall welfare of turbot.

From clinic to mechanism: Proteomics-based assessment of angiogenesis in adrenal pheochromocytoma.

Adrenal pheochromocytoma (PCC) is a very rare tumor that stems from chromaffin cells, which can develop into malignant tumor. During the operation, abundant blood vessels were often observed in PCC than other adrenal tumors, which increases the difficulty and risk of the surgery. Therefore, it is important to investigate the mechanism of PCC angiogenesis. Twelve surgical specimens of PCC from Ruijin Hospital, Shanghai Jiaotong University were grouped into high and low microvessel density (MVD) group. They were also divided into rich blood supply and nonenriched blood supply group, according to computed tomography (CT) manifestation. Comparative proteomic analysis based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and bioinformatics analysis revealed that 206 proteins differentially regulated in the high MVD group compared with low MVD group (p < 0.05). Besides, 61 proteins were discovered to be significantly changed when the 12 samples were grouped according to CT manifestation. By intersecting the differentially changed protein from MVD and CT grouping, 25 proteins were filtered out, with pathological function. COX4I2 was verified to be increased gradually with angiogenesis with increasing severity, and PLAT was shown to be decreased with angiogenesis in PCC, by quantitative reverse-transcription polymerase chain reaction and immunohistochemistry. The quantitative proteomics result indicated that the tumor angiogenesis in PCC is associated with hypoxia. COX4I2 and PLAT were highly correlated with blood supply in PCC which contribute to angiogenesis in PCC, which could be used as biomarkers to better indicate tumor angiogenesis, or targets to regress tumor angiogenesis as treatment.

Effects of Erbium:Yttrium-Aluminum-Garnet Laser Irradiation on Bovine Dentin Contaminated by Cariogenic Bacteria.

Objective: This study was performed to determine the bactericidal effects of erbium:yttrium-aluminum-garnet (Er:YAG) laser irradiation and the morphological and chemical composition changes in bovine dentin. Methods: Dentin slabs were prepared from bovine incisors, and then cultured with Streptococcus mutans to produce bacteria-infected dentin samples. The samples were randomly divided into five groups with Er:YAG laser irradiation energy densities of 0, 6.37, 12.73, 19.11, and 25.47 J/cm2. After irradiation, samples were stained and observed by confocal laser scanning microscopy. The bactericidal abilities were measured using live/dead staining. The morphology and chemical components were investigated by scanning electron microscopy and energy-dispersive spectrometry. Results: After irradiation, the elimination of bacteria and the smear layer were significantly better in the high energy density groups (19.11, 25.47 J/cm2) than in the low energy density groups (6.37, 12.73 J/cm2; p < 0.001). On morphological examination, the group with minimum energy density (6.37 J/cm2) showed superficial melting. In the high energy density groups (12.73, 19.11, and 25.47 J/cm2), laser-irradiated dentin showed a clean surface with open orifices. Significant increases were observed in the weight percentages of calcium (from 19.75 ± 0.69 to 34.47 ± 2.91, p < 0.001) and phosphate (from 8.58 ± 0.43 to 15.10 ± 1.81, p < 0.001), whereas significant decreases were observed for oxygen (from 49.84 ± 0.69 to 36.39 ± 2.86, p < 0.001) and carbon (from 26.06 ± 3.58 to 12.80 ± 2.26, p < 0.01) with increasing energy density. Conclusions: This study confirmed that Er:YAG laser irradiation has bactericidal and dentin conditioning effects.

Mutual equidistant-scattering criterion: A new index for crisp clustering

Clustering algorithms usually assume that the number K of clusters is known, although there is often no prior knowledge about the underlying set. Consequently, the significance of the defined groups needs to be validated. Cluster validity indexes are commonly used to perform the validation of clustering results. However, most of them are considered to be dependent on the number of data objects and often tend to ignore small and low-density groups. Furthermore, suboptimal clustering solutions are frequently selected when the clusters are in a certain degree of overlapping or low separation. Thus, we propose a new non-parametric internal validity index based on within-cluster mutual equidistant-scattering for crisp clustering. Eight different validity indexes were analysed to detect the number of clusters in a data set. Experiments on both synthetic and real-world data show the effectiveness and reliability of our approach to evaluate the hyperparameter K.

Stable Tracheal Regeneration Using Organotypically Cultured Tissue Composed of Autologous Chondrocytes and Epithelial Cells in Beagles.

In tracheal regeneration, the slow process of epithelialization is often a barrier to the stability and safety of the transplanted trachea. The aim of this study was to examine a new tracheal regeneration technique using organotypically cultured tissue composed of autologous cells. Nine beagles were prepared. Chondrocytes from auricular cartilage and epithelial cells from buccal mucosa were isolated and cultured. Tissue-engineered cartilages were fabricated with chondrocytes at a density of 1 × 107 cells/mL (high-density group) and 1 × 106 cells/mL (low-density group). A fabricated epithelial cell sheet was laid on a poly(lactic-co-glycolic acid) block in atelocollagen gel containing the chondrocytes, and the organotypically cultured tissues were transplanted into a partially resected trachea. The control group had only the block transplanted. The tissue-engineered cartilages in the high-density group contained many viable chondrocytes and many cartilage matrices. The low-density group had abundant collagen fibers and no chondrocytes. Tracheal endoscopy revealed no deformation or atrophy at the transplant site in the high-density group. Histologically, partially hyaline cartilages covered with epithelium and lamina propria were found in the high-density group but not in the low-density and control groups. Stable tracheal regeneration was achieved using organotypically cultured tissue fabricated with autologous high-density chondrocytes and epithelial cells.

The Importance of Wall Apposition in Flow Diverters.

It is assumed that high pore densities in flow diverters (FDs) are beneficial for intracranial aneurysm (IA) healing. However, various animal studies are not conclusive on the issue, suggesting that other factors are in play. One important factor might be wall apposition. To (1) determine the relationship between FD pore density and aneurysm occlusion, and (2) determine the relationship between FD wall apposition and aneurysm occlusion. Saccular aneurysms were microsurgically created in the aorta of 36 Wistar rats. Twelve rats received a low pore density FD (10 pores/mm2), 12 rats received a high pore density FD (23 pores/mm2), and the remaining 12 rats served as a control group. Six animals from each group were sacrificed 1 and 3 mo after surgery. We determined aneurysm occlusion, the number of struts not in contact with the aorta wall, and the average distance from malapposed struts to aorta wall through histology. No significant differences were found in aneurysm occlusion between the low pore density and high pore density groups (P>.05) after 1 and 3 mo of follow-up. The average number of malapposed struts was lower for the occluded aneurysm group (4.4±1.9) compared to the nonoccluded aneurysm group (7.7±2.6, P<.01). The average distance between malapposed struts and parent artery wall was lower for the occluded aneurysm group (33.9 μm±11.5 μm) than for the nonoccluded aneurysm group (48.7 μm±18.8 μm, P<.05). Wall apposition is more important than pore density for aneurysm occlusion.

Transcriptomic insight into antimicrobial peptide factors involved in the prophylactic immunity of crowded Mythimna separata larvae

Similar to pathogenic infection, a high population density alters insect prophylactic immunity. Antimicrobial peptides (AMPs) are known to play critical roles in an insect's humoral immune response to microbial infection. We applied RNA sequencing to investigate differential gene expression levels in fat body and hemocyte samples from larvae reared in high- (10 larvae per jar) and low-density (1 larva per jar) conditions; the samples exhibited density-dependent prophylaxis. A number of AMP molecule-related proteins were annotated for the first time from 145,439 assembled unigenes from M. separata larvae. The transcript levels of AMP molecules such as gloverin-, defensin-, cecropin-, lebocin- and attacin-related unigenes were increased with the prophylactic immunity of high-density larvae. The pattern recognition receptor peptidoglycan recognition protein (PGRP), a key protein in the synthesis of AMPs in IMD- and Toll pathway-related unigenes, was also upregulated in the larvae from the high-density group. The resultant transcriptomic database was validated by the transcript levels of four selected AMP genes quantified from the high- and low-density larval groups with quantitative real-time PCR. The antimicrobial activity against gram-positive Staphylococcus aureus and Bacillus subtilis and gram-negative Edwardsiella ictaluri and Vibrio anguillarum in the hemolymph of larvae from the high-density group was significantly higher than that of larvae from the low-density group. Our findings provide the first insight into the role of AMP genes in the mechanisms of density-dependent prophylaxis in M. separata and provide new insight into the control of M. separata with biopesticides.

Effects of stocking density on growth performance and metabolism of juvenile Lenok (Brachymystax lenok)

A 127 day growth trial was conducted to investigate the impact of stocking density on growth performance and metabolism of the lenok (Brachymystax lenok). Juvenile lenok were stocked in triplicate at 4 initial densities (0.74, 1.53, 3.15, and 6.11 kg m−3). Samples were taken at days 30, 60, 97 and 127 of the experiment. At day 30, a lower specific growth rate (SGR) with higher feeding rate (FR) and lower feed efficiency (FER) in the low stocking density group (D1; initial density, 0.74 kg m−3) was observed compared with the high stocking density group (D4, initial density, 6.11 kg m−3). In contrast, a reduced SGR in D4 at days 97 and 127 was observed compared with D1. However, significant metabolic differences of plasma and liver were only observed between D1 and D4 using nuclear magnetic resonance (NMR)-based metabolomics analyses at the end of the experiment, including activation of energy metabolism, alterations in amino acid metabolism, changes in choline metabolism and repression of lipid metabolism. Gas chromatography-mass spectrometer (GC–MS) was then used to identify specific fatty acid in plasma, and the results showed that there were significant reductions of n-3PUFA, n-6 PUFA, MUFA and SFA in D4 compared with D1 at day 127. In conclusion, high stocking density resulted in detrimental effects on growth performance and alterations in metabolism of the lenok, suggesting that the welfare of the lenok at this size could be adversely affected by high fish density.

The effects of crowding stress on the growth, physiological response, and gene expression of the Nrf2-Keap1 signaling pathway in blunt snout bream (Megalobrama amblycephala) reared under in-pond raceway conditions

We evaluated the effects of high density stress on growth performance, antioxidant parameters, and Nrf2 pathway signaling molecules after different lengths of exposure (30, 60, or 90 days) of Megalobrama amblycephala to in-pond raceway aquaculture systems (IPRS). M. amblycephala (average initial weight 2.33 ± 0.15 g) were reared at two different initial densities (low density group [LD] had 534 fish/m3 and high density group [HD] had 1073 fish/m3) for 90 days. The growth performance was adversely influenced by the high stocking density. The HD group had elevated white blood cell counts, hemoglobin content, and hematocrit on days 60 and 90. The mRNA levels of NOX2 on days 60 and 90, Nrf2 on days 30, 60, and 90, Keap1 on day 30, Bach1 on days 30 and 60, SOD on day 30, and CAT on day 30 were significantly higher in the HD group than in the LD group. Similarly, higher trends were observed in the enzymatic activities of SOD on day 60, CAT on days 60 and 90, and GPx on day 60 in the HD group, compared to the LD group. Furthermore, HD bream showed an increased MDA content on days 60 and 90 compared to that of the LD group. This study demonstrates that high density-induced antioxidant defenses were involved in modifications to the enzymatic and transcriptional regulation of Nrf2-Keap1 signaling molecules and that M. amblycephala growth was reduced in a crowded IPRS.

Bellamya aeruginosa (Reeve) promote the growth of Elodea nuttallii (Planch.) H. St John in high nutrient environment

Elodea nuttallii (Planch.) H. St John is an invasive alien submerged macrophyte, which grows very fast and dominates in many Chinese waters. Bellamya aeruginosa (Reeve) is a widely distributed benthonic organism in China. This snail species rarely grazes submerged macrophytes and may promote their growth by feeding on epiphyte and phytoplankton. The above two species can commonly be found together in nature waters and their interaction may promote the growth of both species, which could disturb the ecological balance. In this paper, effects of different densities of B. aeruginosa at two different nutrient stages on water quality and the growth of E. nuttallii were studied. The results showed that the growth rates (GRs) of E. nuttallii were not significantly affected by different B. aeruginosa densities in the low nutrient (LN) stage. However, in the high nutrient (HN) stage, the GRs of the aboveground parts of E. nuttallii in the high density (HD) groups were considerably higher than the control (CK) and low density (LD) groups. The water chlorophyll (Chl) and nitrate-nitrogen (NO3-N) contents increased substantially with increasing B. aeruginosa density in the LN stage, while the Chl and NO3-N contents in the LD groups were significantly higher than in the HD and CK groups in the HN stage. The results of this paper indicated that B. aeruginosa could promote the growth of E. nuttallii by reducing the Chl contents in the water in high-nutrient environment rather than in low-nutrient environment, which highlighted that B. aeruginosa may strengthen the invisibility of E. nuttallii in eutrophic water caused by human activities.

Discussion on the Relationship between Dieting and Bone Density among Female College Students and the Health Guidance

We studied the relationship between dieting and bone density among female college students and the current state thereof. Female college students are generally thin, with the time to giving birth and raising the next generation approaching. We expect the results of this study will be useful in improving health guidance. The subjects consisted of 124 female college students. Their average age was 21.4. The ultrasonic propagation velocity of the heel bone was measured as the bone density value. Body height, weight, and BMI (Body mass index) were also measured. Further, a multiple choice and short answer survey was conducted regarding their desire to be thin and dieting. Classifying the subjects by BMI, 16 students were underweight (13%), 102 students were of normal weight (84%), and 4 students were overweight (3%). 95% of those in the normal weight group had a desire to be thin, while 44% of the underweight group had a desire to be thin. Moreover, 31% of those in the normal weight group were currently on a diet, while 21% of the underweight group was also on a diet. The distribution of bone density (%YAM value: Young Adult Mean) was as follows: 61 students (49%) were in the high density group (≥100); 58 students (47%) were in the middle density group (≥80 - <100); and 5 students (4%) were in the low density group (<80). The more the bone density decreased, the greater the proportion of students with dieting experience. Among students with no dieting experience, the %YAM value was high when the BMI value was high. All of the students in the low density group had a desire to be thin, even though their bone density was low. Students who do not need to be thin had a desire to be thin and were considering continuing dieting going forward. Moreover, some students fell into the %YAM low density group, which is worrisome for the future. It is believed necessary to reinforce health guidance regarding dieting and bone density in school education. In particular, it is necessary to improve guidance since we observed a lack of knowledge regarding osteoporosis prevention.

COMPARISON OF IMPLANT DENSITY IN THE MANAGEMENT OF LENKE 1B AND 1C ADOLESCENT IDIOPATHIC SCOLIOSIS.

ABSTRACTObjective:To compare radiographic and surgical outcomes of Lenke 1B and 1C patterns.Methods:One hundred twenty patients with Lenke 1B and 1C scoliosis were grouped according to implant density as follows: low density (LD) of ≤1.4 and high density (HD) of >1.4. Matched subgroups (30 patients each) based on age, curve magnitude, and body mass index (BMI) were analyzed. Radiographic parameters were evaluated before operation, immediately after operation (ipo), and at 2 years’ follow-up. SRS-30 was administered before operation and at 2 years’ follow-up.Results:The major curves of the LD (n = 82) and HD groups (n=38) were respectively 59.1° and 65.6° before operation (p <.001), 26.3° and 22.9° ipo (p =.05), and 29.9° and 19.8° at 2 years’ follow-up (p <.001). No significant differences in postoperative trunk shift and coronal balance were found (p =.69 and p =.74, respectively). The HD group had higher blood loss (p =.02), number of implants (p <.001), levels fused (p =.002), and surgical time (p <.001). The HD group had a higher prevalence of hypokyphosis from before operation to follow-up (p <.001). No significant differences were observed in the SRS-30 scores before operation and at 2 years’ follow-up. The matched groups had similar preoperative major curves (p =.56), ages (p =.75), and BMIs (p =.61). Significantly longer surgical time (p =.009), higher density (p <.001), and better correction (p =.0001) were found in the HD group at 2 years’ follow-up. No significant differences were found in the SRS-30 scores before operation and at 2 years’ follow-up.Conclusion:LD constructs included fewer segments fused, lower intraoperative estimated surgical blood loss, and shorter operation time, and potentially decreasing complication risks due to fewer implants. Level of evidence III, Retrospective Cohort Study.

Association between metabolic profiles in urine and bone mineral density of pre- and postmenopausal Chinese women

In the present study, we aimed to characterize the pathological development of menopausal osteoporosis, as well as to explore potential biomarkers and metabolic pathways involved in osteoporosis. Urine samples from 322 female participants categorized by menopause status and different bone conditions were collected and analyzed based on a gas chromatography-mass spectrometry (GC-MS) approach. Multivariate and univariate statistical analyses were carried out for urinary metabolomic profile characterization and comparison. Seventeen metabolites in the low bone mineral density (BMD) groups were clearly differentiated from those in normal BMD groups. Among these 17 differentiating metabolites, taurine, β-alanine, and 5-hydroxycaproic acid were found to be potential biomarkers of osteoporosis. The taurine metabolic pathway and the β-alanine metabolic pathway were found to be related to menopause and bone loss. Based on the GC-MS metabolomic platform, four typical pathological phases during the progression of postmenopausal osteoporosis were described. Several differentiating metabolites and metabolic pathways were found to be closely related to the pathology of postmenopausal osteoporosis. Our results provided a solid foundation for further studies on early diagnosis and pathomechanistic evaluation.

Effects of stocking density on the growth and immunity of Atlantic salmon salmo salar reared in recirculating aquaculture system (RAS)

Atlantic salmon reared in recirculating aquaculture system (RAS) may lead to inappropriately high stocking density, because fish live in a limited space. Finding the suitable stocking density of Atlantic salmon reared in RAS is very important for RAS industry. In this paper, the influence of stocking density on growth and some stress related physiological factors were investigated to evaluate the effects of stocking density. The fish were reared for 220 days at five densities (A: 24 kg/m3; B: 21 kg/m3; C: 15 kg/m3; D: 9 kg/ m3 and E: 6 kg/m3 ). The results show that 30 kg/m3 might be the maximum density which RAS can afford in China. The stocking densities under 30 kg/m3 have no effect on mortality of Atlantic salmon reared in RAS. However, the specific growth rate (SGR), final weight and weight gain in the high density group were significantly lower than the lower density groups and middle density groups. Moreover, feed conversion rate (FCR) had a negative correlation with density. Plasma hormone T3 and GH showed significant decrease with the increase of the stocking density of the experiment. Furthermore, thyroid hormone (T3), GH (growth hormone) activities were decreased with stocking density increase. However, plasma cortisol, GOT (glutamic oxalacetic transaminase) and GPT (glutamic pyruvic transaminase) activities were increase with stocking density increase. And the stocking density has no effects on plasma lysozyme of Atlantic salmon reared in RAS. These investigations would also help devise efficient ways to rear adult Atlantic salmon in China and may, in a way, help spread salmon mariculture in China.

Larval crowding results in hormesis-like effects on longevity in Drosophila: timing of eclosion as a model.

There is increasing evidence that stress during development can affect adult-life health status and longevity. In the present study, we examined life span (LS), fly weight, fecundity and expression levels of longevity-associated genes (Hsp70, InR, dSir2, dTOR and dFOXO) in adult Drosophila melanogaster flies reared in normal [low density (LD), ~ 300-400 eggs per jar] or crowded [high density (HD), more than 3000 eggs per jar] conditions by using the order (day) of emergence as an index of the developmental duration (HD1-5 groups). Developmental time showed a significant trend to increase while weight showed a significant trend to decrease with increasing the timing of emergence. In both males and females eclosed during first 2days in HD conditions (HD1 and HD2 groups), both mean and maximum LSs were significantly increased in comparison to LD group. In males, mean LS was increased by 24.0% and 23.5% in HD1 and HD2 groups, respectively. In females, corresponding increments in mean LS were 23.8% (HD1 group) and 29.3% (HD2 group). In HD groups, a strong negative association with developmental time has been found for both male and female mean and male maximum LSs; no association with growth rate was observed for female maximum LS. The female reproductive activity (fecundity) tended to decrease with subsequent days of eclosion. In HD groups, the levels of expression of all studied longevity-associated genes tended to increase with the timing of eclosion in males; no differences were observed in females. On the basis of findings obtained, it can be assumed that the development in conditions of larval overpopulation (if not too extended) could trigger hormetic response thereby extending the longevity. Further studies are, however, needed to confirm this assumption.

Response of the gut microbiome of Megalobrama amblycephala to crowding stress

Environmental factors, including drugs and diet, have been shown to affect the microbiome composition. However, whether physical factors affect the gut microbiome composition of fish and whether this change affects fish growth are unknown. The response of gut microorganisms to physical factors such as crowding was assessed by examining the gut microbiome and metabolome of fish from a high-density group and a low-density group. During the 90-day growth period, nine genera of gut microbes were significantly changed between the two groups. In addition, 32 metabolites were significantly changed between the two groups. The correlation analysis of differentially abundant gut microbes and metabolites allowed the identification of eight gut microbes, 13 metabolites and enrichment of seven metabolic pathways. Among the enriched pathways, the pentose phosphate pathway played potential role in the adaption of crowding stress and regulation of glucose metabolism. The response of the pentose phosphate pathway to crowding stress was further determined by evaluating key metabolites, biochemical changes, and the expression of a rate-controlling enzyme in this pathway. Our results provided new evidence that the gut microbiome might be involved in the response to crowding and consequently to the adaptation of fish to environmental stressors via the pentose phosphate pathway.

Analysis of the Correlation between the Myocardial Expression of DPP-4 and the Clinical Parameters of Patients with Heart Failure.

Dipeptidyl peptidase-4 (DPP-4) inhibitors are widely used as antidiabetic drugs. We recently reported that DPP-4 inhibition has beneficial effects on heart failure (HF) mice model. Furthermore, we confirmed that myocardial DPP-4 activity was significantly increased in HF mice compared with non-HF mice. The aim of this study was to investigate the level of myocardial CD26 (DPP-4) expression and its association to clinical parameters in HF patients.Endomyocardial biopsy (EMB) specimens (n = 33) were obtained from HF patients who were admitted to Chiba University Hospital from June 2006 to July 2012. EMB specimens were fixed in formaldehyde and stained with Masson's trichrome staining or with anti-CD26 antibody. Patients were divided into the high CD26 density (CD26-H) or low CD26 density groups (CD26-L). DPP-4 density was compared with blood brain natriuretic peptide (BNP) level and echocardiographic parameters at one year after EMB. Although there were no significant differences in echocardiographic parameters between the CD26-H group and CD26-L group, blood BNP levels were higher in the CD26-H group than in the CD26-L group at one year after EMB. Multivariate regression analysis showed that CD26 density was also an independent determinant of blood BNP levels at one year after EMB.The level of myocardial CD26 expression might be a predictive marker of prognosis in patients with HF.