A trout (Oncorhynchus mykiss) perfusion model approach to elucidate the role of blood removal for lipid oxidation and colour changes in ice-stored fish muscle

Whole body saline-perfused rainbow trout (Oncorhynchus mykiss) was ice-stored for 4\ua0weeks and compared with unwashed/washed minces from unbled and bled trout in terms of rancid odour, peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and redness loss. Muscle from saline-perfused fish, which had 72% less total haem, was deficient in rancid odour during the whole storage, while bled (54% less haem) and unbled samples developed rancid odour already after ~4 and 2\ua0days; higher intensity without bleeding. PV/TBARS also developed in the order unbled\ua0>\ua0bled\ua0>\ua0perfused samples; however, PV/TBARS were not as completely prevented as rancid odour after perfusion. Saline washing (3\ua0 7\ua03 volumes) of unbled mince removed 84% haem and yielded the second most stable sample while saline washing (1\ua0 7\ua01 volumes) destabilised unbled mince, despite 64% haem removal. Concurrent antioxidant removal during washing of minces obviously counteracted the effect of blood removal and washing fish mince with small volumes of solution should be used with great care

Improving the Stability of Red Blood Cells in Rainbow Trout (Oncorhynchus mykiss) and Herring (Clupea harengus): Potential Solutions for Post-mortem Fish Handling to Minimize Lipid Oxidation

This study aimed at limiting hemolysis of fish red blood cells (RBCs) as a strategy to limit hemoglobin (Hb)-induced lipid oxidation during post-mortem handling and processing. Effects of varying temperature, salinity, and mechanical impact were studied using washed resuspended RBCs (wr-RBCs) and whole blood (WB) from rainbow trout (Oncorhynchus mykiss) and herring (Clupea harengus). The wr-RBCs were most stable avoiding mechanical stress, keeping isotonic conditions (0.9–1.3% NaCl) and low temperature 0–6 \ub0C, with predicted minimum at 2.5 \ub0C. When compared at the same salinity, it was found that hemolysis was more pronounced in herring than trout wr-RBCs. Furthermore, WB was more stable than wr-RBCs, showing protecting the effects of blood plasma. Studying individual plasma components, stabilizing effects were found from glucose, proteins, and ascorbic acid. This study indicates that small adjustments in the early handling and processing of fish such as changing salinity of storage and rinsing solutions could minimize Hb contamination of the fish muscle and thereby improve quality

Association between recurrent fracture risk and implementation of fracture liaison services in four Swedish hospitals: A cohort study

Structured secondary preventions programs, called fracture liaison services (FLSs), increase the rate of evaluation with bone densitometry and use of osteoporosis medication after fracture. However, the evidence regarding the effect on the risk of recurrent fracture is insufficient. The aim of this study was to investigate if implementation of FLS was associated with reduced risk of recurrent fractures. In this retrospective cohort study, electronic health records during 2012 to 2017 were used to identify a total of 21,083 patients from four hospitals in Western Sweden, two with FLS (n = 15,449) and two without (n = 5634). All patients aged 50 years or older (mean age 73.9 [SD 12.4] years, 76% women) with a major osteoporotic index fracture (hip, clinical spine, humerus, radius, and pelvis) were included. The primary outcome was recurrent major osteoporotic fracture. All patients with an index fracture during the FLS period (n = 13,946) were compared with all patients in the period before FLS implementation (n = 7137) in an intention‐to‐treat analysis. Time periods corresponding to the FLS hospitals were used for the non‐FLS hospitals. In the hospitals with FLSs, there were 1247 recurrent fractures during a median follow‐up time of 2.2 years (range 0–6 years). In an unadjusted Cox model, the risk of recurrent fracture was 18% lower in the FLS period compared with the control period (hazard ratio = 0.82, 95% confidence interval [CI] 0.73–0.92, p = .001), corresponding to a 3‐year number needed to screen of 61, and did not change after adjustment for clinical risk factors. In the hospitals without FLSs, no change in recurrent fracture rate was observed. Treatment decisions were made according to the Swedish treatment guidelines. In conclusion, implementation of FLS was associated with a reduced risk of recurrent fracture, indicating that FLSs should be included routinely at hospitals treating fracture patients. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research

Continuous gastric saline perfusion elicits cardiovascular responses in freshwater rainbow trout (Oncorhynchus mykiss)

When in seawater, rainbow trout (Oncorhynchus mykiss) drink to avoid dehydration and display stroke volume (SV) mediated elevations in cardiac output (CO) and an increased proportion of CO is diverted to the gastrointestinal tract as compared to when in freshwater. These cardiovascular alterations are associated with distinct reductions in systemic and gastrointestinal vascular resistance (R-Sys and R-GI, respectively). Although increased gastrointestinal blood flow (GBF) is likely essential for osmoregulation in seawater, the sensory functions and mechanisms driving the vascular resistance changes and other associated cardiovascular changes in euryhaline fishes remain poorly understood. Here, we examined whether internal gastrointestinal mechanisms responsive to osmotic changes mediate the cardiovascular changes typically observed in seawater, by comparing the cardiovascular responses of freshwater-acclimated rainbow trout receiving continuous (for 4 days) gastric perfusion with half-strength seawater (1/2 SW, similar to 17 ppt) to control fish (i.e., no perfusion). We show that perfusion with 1/2 SW causes significantly larger increases in CO, SV and GBF, as well as reductions in R-Sys and R-GI, compared with the control, whilst there were no significant differences in blood composition between treatments. Taken together, our data suggest that increased gastrointestinal luminal osmolality is sensed directly in the gut, and at least partly, mediates cardiovascular responses previously observed in SW acclimated rainbow trout. Even though a potential role of mechano-receptor stimulation from gastrointestinal volume loading in eliciting these cardiovascular responses cannot be excluded, our study indicates the presence of internal gastrointestinal milieu-sensing mechanisms that affect cardiovascular responses when environmental salinity changes

Exploring how plasma- and muscle-related parameters affect trout hemolysis as a route to prevent hemoglobin-mediated lipid oxidation of fish muscle

Hemoglobin (Hb) is a powerful promoter of lipid oxidation, particularly in muscle of small pelagic fish species and fish by-products, both having high Hb-levels and highly unsaturated lipids. As Hb is located within the red blood cells (RBCs) it is here hypothesized that the perishable polyunsaturated fatty acids (PUFAs) can be protected from oxidation by limiting hemolysis during early fish processing. Using a model system consisting of washed-resuspended trout (Oncorhynchus mykiss) RBCs (wr-RBCs), the aim of this study was to evaluate how RBC lysis under cold storage was affected by selected parameters linked to blood or muscle: bacterial growth, energy status, pH, RBC membrane lipid oxidation and colloidal osmotic pressure (COP). The results indicated that bacterial growth had a modest effect on hemolysis while pH-values typical for post mortem fish muscle (6.4–6.8), and absence of glucose or albumin stimulated hemolysis. The rapid hemolysis observed at pH 6.4–6.8 correlated with lipid oxidation of the RBC membrane, while the lower hemolysis at pH 7.2–8.0 occurred with low, or without any RBC membrane lipid oxidation. When hemin was added to the RBCs at pH 6.8 hemolysis was induced without parallel RBC membrane oxidation, pointing at Hb-autoxidation and hemin-release per se as important events triggering lysis in fish muscle. Altogether, the study provided valuable findings which ultimately can aid development of new tools to combat lipid oxidation in post mortem fish muscle by limiting hemolysis

The Sub-Pulmonary Conus And The Arterial Anastomosis As Important Sites Of Cardiovascular Regulation In The Crocodile Crocodylus porosus

We present evidence to support the hypothesis that the arterial anastomosis and the cogteeth-like valves located in the sub-pulmonary conus in the right ventricle are important sites of cardiovascular regulation in the crocodile Crocodylus porosus. The influence of the arterial anastomosis on the development of the 'foramen spike' in the left aortic pressure trace, which occurs at the onset of diastole when the pressures in the right and left aortas become equal, and on gastrointestinal blood flow was examined in unanaesthetised C. porosus using blood vessel occluders. Measurements of blood flow in the arterial anastomosis showed that, during non-shunting conditions, there was a substantial systolic blood flow from the right aorta into the coeliac artery. The total coeliac artery blood flow was the sum of the anastomosis flow from the right aorta plus the left aortic flow originating from the right aorta via the foramen of Panizza during diastole. During mechanically induced pulmonary-to-systemic shunting, the anastomosis blood flow was reversed, with blood flowing from the left to the right aorta. The magnitude of the 'foramen spike' was directly related to the vascular resistance in the anastomosis. When vascular resistance in the anastomosis was high, such as during mechanical occlusion, there was an increase in the right aortic to left aortic pressure gradient during systole which resulted in an increase the foramen spike amplitude. Recordings of right intraventricular pressure in unanaesthetised C. porosus showed spontaneous changes in right intracardiac systolic pressure. The pressure recordings were biphasic, with the second contraction (isometric) being highly variable in size, indicating the control of pulmonary outflow resistance, possibly via the 'cogteeth valves' located in the sub-pulmonary conus in the right ventricle

Progeny selection for enhanced forest growth alters soil communities and processes

Genetic enhancement of tree species is integral to global forest management practices with mass propagation of enhanced plant material being used to reforest whole landscapes. It is unclear, however, how genetic enhancement of basic traits such as tree growth may influence the function of life supporting soil ecosystems. We studied the potential cascading effects of genetic increases in growth of Norway spruce (Picea abies) on a range of soil chemical and biological properties. Because this species is a prime candidate for the genetic enhancement of boreal forest landscapes and it has been introduced around the world, its impacts on soil microbiomes are likely of importance both locally and globally. In a 40-year common garden, we assessed how genetic increases in growth generated through controlled crossing of high-quality "plus" trees from across the central boreal zone of Sweden influenced a range of soil properties beneath the canopies. Properties included pH, carbon, nitrogen, nitrate, ammonium, phosphate, respiration rate, and the composition of microbial communities assessed via phospholipid fatty acids (PLFAs). We found that Norway spruce family significantly affected each of the seven chemical properties assessed, with differences of up to 140% among families, and that three of the seven were significantly correlated with mean family growth rate. We also found that fungal PLFAs varied significantly across Norway spruce families, but these differences were not strongly related to mean family growth rate. This study, representing just one cycle of selective breeding, suggests that genetic increases in tree growth rates may also be inadvertently altering soil communities and ecosystem services. Such alterations across forest landscapes may have unexpected implications for the function of forest ecosystems (i.e., nutrient cycling) as well as processes of global significance (i.e., carbon sequestration)

Separation of Test-Free Propositional Dynamic Logics over Context-Free Languages

For a class L of languages let PDL[L] be an extension of Propositional Dynamic Logic which allows programs to be in a language of L rather than just to be regular. If L contains a non-regular language, PDL[L] can express non-regular properties, in contrast to pure PDL. For regular, visibly pushdown and deterministic context-free languages, the separation of the respective PDLs can be proven by automata-theoretic techniques. However, these techniques introduce non-determinism on the automata side. As non-determinism is also the difference between DCFL and CFL, these techniques seem to be inappropriate to separate PDL[DCFL] from PDL[CFL]. Nevertheless, this separation is shown but for programs without test operators.Comment: In Proceedings GandALF 2011, arXiv:1106.081

Energetic savings and cardiovascular dynamics of a marine euryhaline fish (Myoxocephalus scorpius) in reduced salinity

Few studies have addressed how reduced water salinity affects cardiovascular and metabolic function in marine euryhaline fishes, despite its relevance for predicting impacts of natural salinity variations and ongoing climate change on marine fish populations. Here, shorthorn sculpin (Myoxocephalus scorpius) were subjected to different durations of reduced water salinity from 33 to 15 ppt. Routine metabolic rate decreased after short-term acclimation (4-9 days) to 15 ppt, which corresponded with similar reductions in cardiac output. Likewise, standard metabolic rate decreased after acute transition (3 h) from 33 to 15 ppt, suggesting a reduced energetic cost of osmoregulation at 15 ppt. Interestingly, gut blood flow remained unchanged across salinities, which contrasts with previous findings in freshwater euryhaline teleosts (e.g., rainbow trout) exposed to different salinities. Although plasma osmolality, [Na+], [Cl-] and [Ca2+] decreased in 15 ppt, there were no signs of cellular osmotic stress as plasma [K+], [hemoglobin] and hematocrit remained unchanged. Taken together, our data suggest that shorthorn sculpin are relatively weak plasma osmoregulators that apply a strategy whereby epithelial ion transport mechanisms are partially maintained across salinities, while plasma composition is allowed to fluctuate within certain ranges. This may have energetic benefits in environments where salinity naturally fluctuates, and could provide shorthorn sculpin with competitive advantages if salinity fluctuations intensify with climate change in the future