High-level biocidal products effectively eradicate pathogenic γ-proteobacteria biofilms from aquaculture facilities

The use of effective biocides as disinfectants is essential in aquaculture facilities. However, while most biocides act effectively on free-living planktonic pathogens, they are seldom useful against biofilms. In this study, we evaluate the biocidal efficacy and antimicrobial specific contact time of three disinfectants, Virkon™Aquatic (VirA), peracetic acid (PerA), and hydrogen peroxide (HydP), on Vibrio anguillarum, V. harveyi, V. alginolyticus, and Photobacterium damselae subspecies piscicida against their both life phases. By using the minimum inhibitory, bactericidal, and eradication concentrations of disinfectants acting on the free-living planktonic state (MIC; MBC) and biofilms (MBIC; MBEC), we determined the in vitro susceptibility of each bacterial strain against three different individual concentrations of VirA, PerA, and HydP added at 1, 5, and 10 min intervals. PerA and VirA had the highest bactericidal efficacies against the free-living planktonic state and biofilm of all bacteria. Kinetically, PerA gave a positive result more quickly in both cases regardless of the strain in question, while the weakest HydP required longer than 10 min to act effectively. Moreover, we conducted a short in vivo safety trial by pouring the suggested MIC of each disinfectant into tanks containing juvenile Gilthead seabream (Sparus aurata). Significant mortality after 24 h was observed pointing to the potential risk a mishap of these chemicals might cause to fish. Nevertheless, collectively, our results support the inclusion of biocides within biosecurity protocols in aquaculture facilities and highlight PerA as the most effective disinfectant for fighting against biofilms produced by V. anguillarum, V. harveyi, V. alginolyticus or P. damselae subsp. piscicida.publishedVersionUnit License Agreemen

An evaluation of the 30-s chair stand test in older adults: frailty detection based on kinematic parameters from a single inertial unit

Background: A growing interest in frailty syndrome exists because it is regarded as a major predictor of co-morbidities and mortality in older populations. Nevertheless, frailty assessment has been controversial, particularly when identifying this syndrome in a community setting. Performance tests such as the 30-second chair stand test (30-s CST) are a cornerstone for detecting early declines in functional independence. Additionally, recent advances in body-fixed sensors have enhanced the sensors’ ability to automatically and accurately evaluate kinematic parameters related to a specific movement performance. The purpose of this study is to use this new technology to obtain kinematic parameters that can identify frailty in an aged population through the performance the 30-s CST. Methods: Eighteen adults with a mean age of 54 years, as well as sixteen pre-frail and thirteen frail patients with mean ages of 78 and 85 years, respectively, performed the 30-s CST while threir trunk movements were measured by a sensor-unit at vertebra L3. Sit-stand-sit cycles were determined using both acceleration and orientation information to detect failed attempts. Movement-related phases (i.e. impulse, stand-up, and sit-down) were differentiated based on seat off and seat on events. Finally, the kinematic parameters of the impulse, stand-up and sit-down phases were obtained to identify potential differences across the three frailty groups. Results: For the stand-up and sit-down phases, velocity peaks and “modified impulse” parameters clearly differentiated subjects with different frailty levels (p < 0.001). The trunk orientation range during the impulse phase was also able to classify a subject according to his frail syndrome (p < 0.001). Furthermore, these parameters derived from the inertial units (IUs) are sensitive enough to detect frailty differences not registered by the number of completed cycles which is the standard test outcome. Conclusions: This study shows that IUs can enhance the information gained from tests currently used in clinical practice, such as the 30-s CST. Parameters such as velocity peaks, impulse, and orientation range are able to differentiate between adults and older populations with different frailty levels. This study indicates that early frailty detection could be possible in clinical environments, and the subsequent interventions to correct these disabilities could be prescribed before further degradation occurs.The authors are indebted to the Spanish Department of Health and Institute Carlos III of the Government of Spain [Spanish Net on Aging and frailty; (RETICEF)], Department of Health of the Government of Navarre and Economy and Competitivity Department of the Government of Spain, for financing this research with grants numbered RD12/0043/0022, 87/2010, and DEP2011-24105 respectively

Effect of increasing docosahexaenoic acid content in weaning diets on survival, growth and skeletal anomalies of longfin yellowtail (Seriola rivoliana, Valenciennes 1833)

Five isoproteic (54.8%) and isolipidic (24.1%) microdiets, which varied in their docosahexaenoic acid (DHA) content (0.25, 0.75, 1.64, 1.99 and 3.17%; dw), were manufactured to determine its effects on longfin yellowtail Seriola rivoliana larvae in terms of fish biological performance, whole body fatty acid profile and incidence of skeletal anomalies from 30 dah (11.31 &plusmn; 1.79 Total Length, TL) to 50 dah (19.80&plusmn;0.58 mm TL). The inclusion of dietary DHA up to 3.17% (dw) improved larval resistance to air exposure, although DHA did not significantly affect fish final growth or final survival. Indeed, high levels of dietary DHA (1.99% and 3.17%, dw) tended to increase the incidence of skeletal anomalies in S. rivoliana larvae, albeit no significant differences were observed. Furthermore, the occurrence of severe anomalies such as kyphosis and lordosis, was mainly associated to the larvae fed with the highest levels of dietary DHA. In terms of survival, increasing dietary DHA levels did not significantly affect longfin yellowtail survival rate, despite a tendency for enhanced survival. The results of the present study proved that the inclusion of dietary DHA in inert diets up to a 3.17% (dw) and a DHA/EPA ratio above 3.1 increased the final survival and stress resistance in S. rivoliana larvae

Physiological pathways involved in nutritional muscle dystrophy and healing in European sea bass (Dicentrarchus labrax) larvae

The potential muscle regeneration after nutritional dystrophy caused by high dietary DHA contents in fish and the physiological pathways involved are still unknown. To better understand this process, an experiment was conducted for 3 weeks in 14 day-old European sea bass larvae using different DHA ratios (1 or 5%). After this period, part of the larvae fed 5% DHA diet was switched to 1% DHA diet ("wash-out") for another 2 weeks. Larvae fed 5% DHA diet showed altered oxidative status as indicated by the highest TBARS values, antioxidant enzymes (AOE) expression and incidence of muscular lesions. Accordingly, "washed-out" larvae showed lower dry weight and &alpha;-TOH content. IGF-I gene expression was elevated in 5% DHA larvae at 35 dph, suggesting increased muscle mitogenesis that was corroborated by the increase in myosin heavy chain expression. It can be concluded that high dietary DHA contents alter the oxidative status and cause muscular lesions in European sea bass larvae, with morphological and molecular aspects of mammalians muscular degenerative disease

Supplementation of vitamin E and C prevent granulomatosis in meagre larvae

Systemic granulomatosis has already been reported in meagre larvae with an adequate feeding protocol and enrichment media preventing its appearance in the first weeks of life. Afterwards, the control of this disease could be prevented through nutritional components of the inert food, being the antioxidants the key to success. For this reason, in the present study, meagre larvae were reared from 30 days post hatching (dph) with five isonitrogenous and isolipidic experimental microdiets with different levels of vitamin E and C: C- (40 mg kg-1 E, 100 mg kg-1 C), C+ (400 mg kg-1 E, 1,000 mg kg-1 C), Krill (400 mg kg-1 E, 1,000 mg kg-1 C and substitution of fish oil by krill oil), EC (200 mg kg-1 E, 500 mg kg-1 C) and EECC (800 mg kg-1 E, 2,000 mg kg-1 C). Prior to this, larvae were co-fed with rotifers and Artemia following a protocol which prevented the appearance of granulomas, as previously demonstrated. The substitution of fish oil by krill oil significantly increased levels of eicosapentaenoic acid (EPA, 16.6 %) and docosahexaenoic acid (DHA, 17.6 %) in meagre, consequently increasing the peroxidation index, which in turn translated into a higher incidence of granulomas. Although even low levels of vitamin E and C (40 mg kg-1 E, 100 mg kg-1 C; C-) allowed the adequate growth of larvae, these levels were not enough to prevent the appearance of granulomas, requiring superior levels of both antioxidant vitamins (800 mg kg-1 E and 2,000 mg kg-1 C) to mitigate systemic granulomatosis. This mitigation was simultaneous with the reduction of thiobarbituric acid reactive substances TBARs content in larvae, which were highly correlated with the appearance of granulomas (R2=0.892, y=0.0446x+0.0756). A strong negative correlation was observed between the dietary levels of vitamin E (y = -0.0098x + 11.174, R2 = 0.8766, p value = 0.019, r = -0.93) and vitamin C (y = -0.0022x + 6.4777, R2 = 0.9278, p value = 0.003, r = -0.96) and the percentage of larvae with granulomas. The results showed that the occurrence of systemic granulomatosis seems to be associated to the larvae peroxidation status, so that high dietary levels of vitamin E and C (800 and 2,000 mg kg-1, respectively; Diet EECC), reduced lipid peroxidation and completely prevented the appearance of granulomas in meagre larvae at 44 dph

Effects of thermal stress on the expression of glucocorticoid receptor complex linked genes in Senegalese sole (Solea senegalensis): Acute and adaptive stress responses

The present study examined the short and mid-term effects of a rise in temperature from 18 &ordm;C to 24 &ordm;C on the expression of genes related to the stress response regulation in juveniles of Senegalese sole, Solea senegalensis. The animals were exposed to a temperature increase of 6&nbsp;&deg;C, after 1 month of acclimation at 18 &ordm;C. After this process, samples of different tissues were collected from a total of 96 fish at four sampling points: 1 hour, 24 hours, 3 days and 1 week. The transcript levels of a set of genes involved in the stress response such as glucocorticoid receptors 1 and 2, corticotrophin-releasing factor, corticotrophin-releasing factor binding proteins, proopiomelanocortin A and B, and cellular stress defense (heat shock protein 70, 90AA and 90AB) were quantified at these sampling points. Additionally, blood samples were also taken to measure the circulating plasma cortisol concentration.&nbsp; Thermal stress induced by increasing temperature prompted an elevation of plasma cortisol levels in juvenile Senegalese sole after 1 h as a short-term response, and a consecutive increase after one week, as a mid-term response.. Senegalese sole seemed to respond positively in terms of adaptive mechanisms, with a rapid over-expression of grs and hsps in liver and brain, significantly higher after one hour post stress, denoting the fast and acute response of those tissues to a rapid change on temperature. The ratio hsp90/gr also increased 24 h after thermal shock, ratio proposed to be an adaptive mechanism to prevent proteosomal degradation of GR. As a mid-term response, the elevation of brain crfbp gene expression one week after thermal shock could be an adaptive mechanism of negative feedback on HPI axis Taken together, these data suggested an initial up-regulation of the glucocorticoid receptor complex linked genes in response to a temperature increase in Senegalese sole, with heat shock protein 90 potentially being a regulatory factor for the glucocorticoid receptor in the presence of cortisol

Inorganic, organic, and encapsulated minerals in vegetable meal based diets for Sparus aurata (Linnaeus, 1758)

Substituting fishmeal (FM) with vegetable meal (VM) can markedly affect the mineral composition of feeds, and may require additional mineral supplementation. Their bioavailability and optimal supplementation levels depend also on the form of delivery of minerals. The aim of the study was to determine the effect of different delivery forms of three major trace elements (Zn, Mn and Se) in a marine teleost. Gilthead sea bream juveniles of 22.5 g were fed a VM-based diet for 12 weeks that was either not supplemented with these minerals or supplemented with inorganic, organic, or encapsulated inorganic forms of minerals in triplicate and compared to a FM-based diet. Our results showed that mineral delivery form significantly affected the biochemical composition and morphology of posterior vertebrae. Supplementation of VM-based diets with inorganic forms of the target minerals significantly promoted growth, increased the vertebral weight and content of ash and Zn, enhanced bone mineralization and affected the vertebral shape. Conversely, encapsulation of inorganic minerals reduced fish growth and vertebral mineral content, whereas supplementation of organic minerals, enhanced bone osteogenesis by upregulating bone morphogenetic protein 2 (bmp2) gene and produced vertebrae with a larger length in relation to height. Furthermore, organic mineral forms of delivery downregulated the expression of oxidative stress related genes, such as Cu/Zn superoxide dismutase (Cu/Zn sod) and glutathione peroxidase 1 (gpx-1), suggesting thus that dietary minerals supplemented in the organic form could be reasonably considered more effective than the inorganic and encapsulated forms of supply