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With rising environmental temperatures causing concern for the status of freshwater fishes, captive breeding programs may become increasingly important for conservation efforts as well as to support fisheries. Although captive broodstocks provide reliable gamete sources for production stocking, prolonged generations under hatchery conditions can result in changes to fishes as they acclimate to captive settings (domestication) — for example, reduced plasticity due to homogenous captive environments. We assessed the effects of rearing temperature and number of generations spent in captivity on the survival and quality (indicated by lack of malformations) of long-term (F>25) and newly captive (F1) strains of Ontario hatchery brook trout (Salvelinus fontinalis) with shared genetic history. Elevated temperatures decreased likelihood of survival between the pre-exogenous feed and emergent fry stages and had a greater impact on fry quality (rate of malformations) on F1 fish compared with F>25 fish, suggesting no reduction in plasticity due to prolonged captivity. However, overall survival between F1 and F>25 fish was not different. The combined effects of elevated rearing temperatures and number of hatchery generations suggest that (selection) changes due to captivity can occur rapidly even under benign conditions and that additive stressor effects of captivity and temperature have the potential to impact newly established strains. [ABSTRACT FROM AUTHOR]

Concerns have long been raised about the welfare of ballan wrasse (Labrus bergylta) used for the biological control of sea lice in Atlantic salmon (Salmo salar) aquaculture. This study assessed the effect of increased dietary eicosapentaenoic acid (EPA) levels and initial condition factor (CF) on the subsequent performance and welfare of ballan wrasse farmed in high and low water temperatures. Fish were fed a diet with either commercial or high EPA levels for 3 months at 15°C. Subsequently, fish were tagged with a passive integrated transponder, measured for their CF and divided into two groups consisting of fish from both treatments and reared for 4.5 months at either 15 or 6°C fed a commercial diet. Each fish was categorized as high (≥2.7) or low CF (<2.7) fish based on the calculated average CF of the population. Dietary composition influenced the fatty acid (FA) profile of the stored lipids without affecting the growth or welfare of ballan wrasse. Fish reared at 15°C showed higher growth, more fat and energy reserves and less ash content. Fish reared at 6°C lost weight, using up their body lipids at the end of the temperature trial. Gene expression analyses showed upregulation of the positive growth marker (GHrα) and two genes involved in the synthesis and oxidation of FAs (elovl5, cpt1) and downregulation of the negative growth marker (mstn) in fish reared at 15°C compared to those reared at 6°C. Fish reared at 6°C showed upregulated levels of il‐6 compared to those reared at 15°C, suggesting an enhanced immune reaction in response to low temperature. Fish with high CF showed better survival, growth and performance compared to those with low CF. External welfare scoring showed higher prevalence and severity in emaciation, scale loss and the sum index score (of all measured welfare parameters) in fish reared at 6°C compared to those reared at 15°C and better welfare in fish with high CF compared to those with low CF. Histological examination of the skin showed that fish reared at 6°C had decreased epidermal thickness, a lower overall number of mucous cells in the inner and outer epidermis and a different organization of mucous cells compared to fish reared at 15°C, indicating stress in fish reared at 6°C. Overall, low water temperatures had profound effects on the performance and external and internal welfare parameters of ballan wrasse and can be considered a stressor likely affecting the delousing efficacy. These findings support the seasonal use of different cleaner fish species. High CF, but not increased dietary EPA levels, appeared to help fish cope better with low water temperatures and should thus be assessed and considered before deploying them in salmon cages. [ABSTRACT FROM AUTHOR]

Hoverflies (Diptera, Syrphidae) are cosmopolitan, generalist flower visitors and among the most important pollinators after bees and bumblebees. The dronefly Eristalis tenax can be found in temperate and continental climates across the globe, often synanthropically. Eristalis tenax pupae of different generations and different climate zones are thus exposed to vastly different temperatures. In many insects, the ambient temperature during the pupal stage affects development, adult size, and survival; however, the effect of developmental temperature on these traits in hoverflies is comparatively poorly understood. We here reared E. tenax pupae at different temperatures, from 10°C to 25°C, and quantified the effect on adult hoverflies. We found that pupal rearing at 17°C appeared to be optimal, with high eclosion rates, longer wings, and increased adult longevity. Rearing temperatures above or below this optimum led to decreased eclosion rates, wing size, and adult survival. Similar thermal dependence has been observed in other insects. We found that rearing temperature had no significant effect on locomotor activity, coloration or weight, despite evidence of strong sexual dimorphism for each of these traits. Our findings are important as hoverflies are key pollinators, and understanding the effects of developmental temperature could potentially be useful for horticulture. [ABSTRACT FROM AUTHOR]

Objective: Rodent models raised at environmental temperatures of 21–22 °C are increasingly switched to thermoneutral housing conditions in adulthood to better capture human physiology. We quantified the developmental effects of rearing mice at an ambient temperature of 22 °C vs. 30 °C on metabolic responses to cold and high fat diet (HFD) in adulthood. Methods: Mice were reared from birth to 8 weeks of age at 22 °C or 30 °C, when they were acclimated to single housing at the same temperature for 2–3 weeks in indirect calorimetry cages. Energy expenditure attributable to basal metabolic rate, physical activity, thermic effect of food, and adaptive cold- or diet-induced thermogenesis was calculated. Responses to cooling were evaluated by decreasing the ambient temperature from 22 °C to 14 °C, while responses to HFD feeding were assessed at 30 °C. Influences of rearing temperature on thermogenic responses that emerge over hours, days and weeks were assessed by maintaining mice in the indirect calorimetry cages throughout the study. Results: At an ambient temperature of 22 °C, total energy expenditure (TEE) was 12–16% higher in mice reared at 22 °C as compared to 30 °C. Rearing temperature had no effect on responses in the first hours or week of the 14 °C challenge. Differences emerged in the third week, when TEE increased an additional 10% in mice reared at 22 °C, but mice reared at 30 °C could not sustain this level of cold-induced thermogenesis. Rearing temperature only affected responses to HFD during the first week, due to differences in the timing but not the strength of metabolic adaptations. Conclusion: Rearing at 22 °C does not have a lasting effect on metabolic adaptations to HFD at thermoneutrality, but it programs an enhanced capacity to respond to chronic cold challenges in adulthood. These findings highlight the need to consider rearing temperature when using mice to model cold-induced thermogenesis.

ABSTRACT This study evaluated the behavior of broiler chickens subjected to thermal stress during different periods of the day and age of birds. A total of 180 one-day-old male broiler chicks were allocated to three chambers. Each chamber contained five boxes, with 12 chicks/box. Birds were assigned to a completely randomized design. The birds were filmed, and the images recorded every minute during the two periods: morning (from 08:00 to 09:00 h) and afternoon (from 17:00 to 18:00 h), at 7, 14, and 35 d of age. The frequency of the behavioral category (water intake, feed intake, resting, exploration, and comfort) was determined. Data were subjected to variance analysis for mixed models with rearing temperatures (cold, usual, and hot) and age of birds (7, 14, and 35 d) as subdivided plot, and periods of the day (morning and afternoon) as sub-subdivided plot. Birds at cold and usual temperatures showed higher feed intake than those at hot temperature in the morning. Birds exposed to cold and usual temperatures explored the environment less frequently at 35 d when compared with 14 d. However, chickens at hot temperature showed decreased exploration according to the increase of age. Birds spent more time feeding during the morning, regardless of age and rearing temperature. Also, during this period of the day, chickens spent most of the time exploring the environment. The frequency of feed intake and exploration decreases with the increase of age. The similarity of behavior between chickens reared at cold and usual temperatures may be due to a change in the thermal comfort zone of the birds. It suggests that the real thermal comfort temperature is between the two temperature ranges studied (cold and usual).

This study aims to examine the effect of adding nucleotides in broiler rations on the protein mass and calcium mass of broiler chicken reared at different temperatures. The material used was 135 broiler chickens aged 15 days with a weight of 462.20 ± 9 grams of unsex Ross strain and nucleotides imported from China produced by CBH Co. Ltd., China. The study used a completely randomized design (CRD) with a 3x3 factorial pattern with 5 replications. The treatment was carried out at the age of 15-35 days. The treatment given was the first factor adding nucleotides (T0 = nucleotides 0 g/kg feed, T1 = nucleotides 0.5 g/kg feed, T2 = nucleotides 1 g/kg feed) and the second factor was temperature (Heat = S1 = 30 – 32?, Comfortable = S2 = 20 – 23?, Natural = S3 = 24 – 34?). Parameters observed were protein content, calcium content, protein mass, and calcium mass of broiler chicken meat. The research data were analyzed using the F test of variance analysis, if there was a real treatment effect, then Duncan's test was continued. The results showed that there was no interaction between the addition of nucleotides with different maintenance temperatures on protein content, calcium content, protein mass, and calcium mass of meat. Nucleotide 0.05 g had a significant effect (P

Eurasian perch is an important fish species for European aquaculture diversification, but the quality of reproduction still remains one of the main limitations for further industry development. In particular, the optimal condition to obtain the best quality of sperm is poorly understood. The aim of our study was to measure the possible effects of two experimental rearing temperatures (6 °C and the conventionally used 12 °C) and of hormonal stimulation, on the motility parameters (pMOT, VCL, VSL, LIN, ALH, BCF), osmolality and fertilizing capacity of Eurasian perch sperm at the end of the reproductive cycle. A prior untested, large-scale (5 mL cryotube and Polystyrene box) cryopreservation method was implemented using fresh sperm obtained from the two above mentioned temperature groups. Males were injected with 100 μg body weight kg−1 sGnRHa. No significant difference was recorded between the two rearing temperatures and between the saline control and sGnRHa treated groups on the different features of sperm quality. A similar fertilization rate was monitored in all sGnRHa treated (6 °C: 69 ± 13%, 12 °C: 81 ± 11%) and saline control groups (6 °C: 79 ± 10%, 12 °C: 87 ± 4%). Correspondingly, no significant difference in hatching rate was observed in the sGnRHa injected (6 °C: 27 ± 9%, 12 °C: 40 ± 20%) and saline control (6 °C: 35 ± 18%, 12 °C: 36 ± 7%) males. However, a notable negative effect of freezing process on sperm movement was observed following thawing in both temperature groups. No significant difference in the motility parameters was measured between the two temperature groups following large-scale cryopreservation. Furthermore, a similar result was observed in the fertilizing capacity (6 °C: 79 ± 10%, 12 °C: 75 ± 8) of thawed sperm as well as in the hatching rate (6 °C: 52 ± 13%, 12 °C: 46 ± 19%). Our results indicate that fresh Eurasian perch sperm can tolerate a reduced rearing temperature following hormonal treatment. The adopted large-scale cryopreservation method could be used efficiently in the future for the fertilization of large amounts of Eurasian perch eggs following a precise standardization process. • No significant difference was recorded between the two rearing temperatures on the different features of sperm quality. • A similar fertilization and hatching rate was monitored in all sGnRHa treated and saline control groups. • No significant difference in the motility was measured between the two temperature groups following cryopreservation. • A similar high fertilization and hatching rate were measured by the two rearing temperatures using cryopreserved sperm. [ABSTRACT FROM AUTHOR]

Background: The global climate is warming. Heat stress, as a result of high ambient temperatures, may negatively impact physiology and reduce growth performance of poultry. Stevia is a perennial shrub indigenous to South America where its phytochemical extracts have been used as a natural sweetener for hundreds of years. Its physiological effects, including antioxidant properties, on poultry are well known, however, the translation of these to improved growth performance is variable. Combining stevia with a commercial xylanase to enhance feed digestibility could therefore form a feeding strategy to partially mitigate the negative impact of rearing birds under high ambient temperatures. Purpose: The study aimed to compare the growth performance, dietary energy and nutrient availability, oxidative status, gastrointestinal tract development, and caecal short chain fatty acid concentration; at two ambient rearing temperatures, when feeding diets containing stevia and exogenous xylanase, alone or in combination, to broiler chickens.Study design/Methods: Day-old chicks (n = 105) were reared in a single floor pen following breeder recommendations for the first 7 days, whereupon birds (n = 96) were randomly allocated to one of four experimental diets (negative control, stevia at 20 g/kg diet, xylanase at 100 FXU/kg diet, stevia at 20 g/kg diet + xylanase at 100 FXU/kg diet), in one of two environmental conditions (high ambient temperature at 32 ± 2 °C or regular rearing at breeder recommendations), in a 2 × 2 × 2 factorial design. Results: Rearing birds at high ambient temperature reduced daily feed intake (p = 0.02). Birds fed stevia and reared at regular temperature had similar weight gain to birds reared in high ambient temperatures, although birds on the control diet housed at regular temperatures had the greatest weight gain (P

Viral hemorrhagic septicemia virus (VHSV) infection is associated with fatal outcomes in the aquaculture production of olive flounder (Paralichthys olivaceus). Olive flounders at low and high temperatures are known to be highly susceptible and resistant to VHSV infection, respectively. To study temperature-dependent innate immune activity, 4-aminobenzoic hydrazide (4-AH), a myeloperoxidase (MPO) inhibitor, was used to treat VHSV-infected olive flounders reared at a high temperature of 20 °C (20VI). Mortality, the MPO transcription, and the proteomic expression pattern of the 20VI group were then compared with those of groups of VHSV-infected flounders reared at 15 °C (15V) and 20 °C (20V). The cumulative mortality rate of the 20VI group was increased by 35% compared with that of the untreated 20V group. The MPO transcription was decreased 5.8-fold in 20VI than in 20V group. Its expression decreased further at a lower temperature and after exposure to VHSV. Histopathological analysis revealed necrosis of splenic tissue in 20VI and 15V, but not in 20V group. Based on clustering analysis, proteins with increased expression in 15V and 20VI groups were associated with viral mRNA translation and reproduction compared with those of 20V group. Increased expression of DHX58, MX1, and UBB was detected in 15V and 20VI groups, suggesting a role in triggering innate immune response. Unfortunately, these genes failed to induce the translocation of GLUT4 to the surface membrane from the intracellular location due to decreased expression of 14-3-3 proteins (YWHAB and YWHAZ) and microtubules (TUBA1A and TUBB4B). Suppression of glucose supply led to inactivation of MPO and suppression of MHC-I and MHC–II–linked immune activity, resulting in high viral infection and spread. In conclusion, this study highlights that defective GLUT4 translocation-dependent glucose uptake increases the mortality of VHSV-infected olive flounders by inhibiting MPO activity. • MPO expression decreased at low temperature and VHSV infection. • MPO inhibitor increased mortality of VHSV infected olive flounder raised at high temperature. • The suppression of glucose translocation associated with GLUT4 could inactivate MPO related innate immune activity. [ABSTRACT FROM AUTHOR]

Temperatures of worker- and drone-brood rearing in various hive locations were compared in both colonies kept on small-cell combs (4.90 mm) (SMC) and standard-cell combs (5.50 mm) (STC) in two seasons. Temperatures close to the worker-brood comb placed near the rightmost storage-comb were lower than those near the worker brood in the nest centre but equal to those near the outskirt drone-brood comb (34.37-35.24°C) regardless of the month and the comb-cell size. Temperatures of the brood rearing in the SMC did not differ from those in the STC, independently on the location (center-periphery) and the brood type (drone-worker). Occasionally, they were even higher in the STC near the peripheral drone-brood comb and in the nest centre. We concluded that the drones which are involved in colony reproduction could affect its thermoregulation. The peripheral drone brood can be heated just as well as the worker brood, if the colony is strong enough and has the proper drone-worker ratio. Therefore, it is doubtful whether a higher temperature near the worker brood in the SMC limit the development of the V. destructor population. A lower temperature may not be a factor in encouraging V. destructor females to prefer trap-drone-combs for reproduction in the SMC. Strong field colonies may be especially prone to such behaviour. Therefore, temperature cannot be considered a mechanism of effective Varroa control in SMC.

1. This study investigated the oxidative status of broilers fed diets containing selenium (Se) from 14 to 35 d of age and reared at two different constant temperatures. Measurements of oxidative status included blood glutathione peroxidase (GSH-Px) and plasma total antioxidant status (TAS). Other variables included feed intake (FI), weight gain (WG), feed conversion ratio (FCR), Se levels in breast and liver tissue, jejunal villus morphometry, percentage weight of organs in relation to body weight; apparent metabolisable energy adjusted for nitrogen (AMEn); dry matter retention (DMR); fat retention (FR) and nitrogen retention (NR). 2. The experiment started at 14 d of age, when 240 birds were randomly allocated to 48 pens (12 pens in four rooms). Treatments included a control diet 1 (SFC; 209.4 g/kg CP and 12.98 MJ/kg ME and no added Se containing saturated fat); diet 2 (SFSe) the control plus 12.605 mg/kg Se additive; diet 3 (USFC) was a second control diet (208.2 g/kg CP and 13.10 MJ/kg ME with no added Se containing unsaturated fat as rapeseed oil); diet 4 (USFSe) was the latter control plus 12.605 mg/kg Se additive. Two rooms were kept at a standard temperature of 20°C (ST) and two rooms were kept at high temperature of 35°C (HT). 3. A temperature x Se interaction existed for GSH-Px in birds reared at ST (P < 0.05), and these birds had the highest levels of Se in liver tissue (P < 0.05). Fat x Se interactions were evident in breast tissue with highest levels in USFSe (P < 0.05). Adding Se improved jejunal VH: CD in USFSe fed birds (P < 0.001). 4. Birds reared at ST had higher FI and WG than those reared at HT (P < 0.001), and had lower FCR than those reared at HT (P < 0.05). AMEn (MJ/kg DM) and FR were higher in birds fed USF diets, and lowest in birds fed SF (P < 0.50 and P < 0.001 respectively). NR was highest in birds raised at ST (P < 0.50). 5. Broiler growth performance was reduced by HT. Oxidative status and Se in liver tissue was improved by adding Se in both diets. [ABSTRACT FROM AUTHOR]

Currently, no information is available on the effect of progressively decreasing temperatures on the sensory quality of Arctic charr. The objective of this study was to investigate if and how different and progressively changing rearing temperatures affect the sensory quality of cooked and raw fillets of Arctic charr. The effects of rearing temperature on the sensory quality of Arctic charr (weight range 622–888 g) were investigated. Rearing temperature was changed during the experimental period as the fish were reared at constant or decreased temperature during October to April and subsequently reared at two constant temperatures from April to August establishing six different rearing temperature combinations. Significant differences were seen in all four main sensory attributes groups, that is odour, appearance, flavour and texture. Freshness characteristics such as sweet odour and flavour, and metallic odour and flavour increased with decreasing rearing temperature, whereas musty odour and flavour decreased. Rearing temperature had a clear effect on the colour of the fillets. Lower rearing temperature increased colour intensity substantially. Softness, juiciness and tenderness increased with decreased rearing temperature. A trend was seen towards more effect from final rearing temperature than initial temperature on the sensory attributes studied. Spoilage characteristics, that is, sour and rancid odour and flavour, and off‐odour and flavour were either very weak or not noticeable in all sample groups. [ABSTRACT FROM AUTHOR]

Thermoregulation, that is, the active control of temperature, is key to ensure proper brood development in both wild and captive bumblebee nests. In this study, thermoregulation dynamics were assessed relative to colony age and ambient temperature using commercially reared Bombus terrestris L. (Hymenoptera, Apidae, Bombus) colonies. We observed a positive relationship between brood and nest temperatures in response to ambient temperature. Thermoregulation investment (by either brooding or fanning) was lowest at brood surface temperatures between 33 and 34 °C and ambient temperatures between 28 and 32 °C. Brood temperature was less stable and thermoregulation investment higher in younger colonies, especially at lower ambient temperatures. Furthermore, queens initiated colonies sooner and colonies developed faster when kept at an ambient temperature of 29 °C as compared to 24 °C. Our results suggest that ambient temperatures are ideally kept between 29 and 31 °C. [ABSTRACT FROM AUTHOR]

The present study aims to isolate, identify, and evaluate potential probiotic, Lactic Acid Bacteria (LAB) from the gut and hepatopancreas of 10 healthy wild giant freshwater prawn, Macrobrachium rosenbergii. The samples were cultivated using a modified De Man, Rogosa and Sharpe (MRS) agar supplemented with 2% of CaCO3 (w/v). Bacterial colonies with strong clear zone were selected for further tests. From these, 17 isolates of LAB showed non-spore forming, homofermentative characteristics, Gram-positive, rod-shaped, non-motile bacteria and absences of catalase enzymes. The LAB was further identified using API 50 CH kit and 16S rRNA. The isolates LAB also showed tolerance to a variety of environmental conditions like pH, temperature, salt, bile and hemolysis activity in in vitro condition. Based on the results, two isolates LAB were identified as Lactobacillus plantarum and Entercoccus faecalis were suggested as potential probiotic candidates from giant freshwater prawn for Aquaculture industries.

Abstract Background As ectothermic animals, temperature influences insects in almost every aspect. The potential disease spreading Asian bush mosquito (Aedes japonicus japonicus) is native to temperate East Asia but invasive in several parts of the world. We report on the previously poorly understood temperature-dependence of its life history under laboratory conditions to understand invasion processes and to model temperature niches. Results To evaluate winter survival, eggs were exposed between 1 day and 14 days to low temperatures (5 °C, 0 °C, -5 °C and -9 °C). Hatching success was drastically decreased after exposure to 0 °C and -5 °C, and the minimal hatching success of 0% was reached at -9 °C after two days. We then exposed larvae to 14 temperatures and assessed their life trait parameters. Larval survival to adulthood was only possible between 10 °C and 31 °C. Based on this, we modelled the optimal (25 °C), minimal (7 °C) and maximal (31 °C) temperature for cumulative female survival. The time to adult emergence ranges from 12 days to 58 days depending on temperature. We used an age-at-emergence-temperature model to calculate the number of potential generations per year for the Asian bush mosquito in Germany with an average of 4.72 potential generations. At lower temperatures, individuals grew larger than at higher temperatures with female R1 length ranging from 3.04 ± 0.1 mm at 31 °C to 4.26 ± 0.2 mm at 15 °C. Conclusions Reduced egg hatch after exposure to sub-zero temperatures prohibits the establishment of the Asian bush mosquito in large parts of Germany. Larval overwintering is not possible at temperature ≤ 5 °C. The many potential generations displayed per year may contribute to the species’ invasion success. This study on the thermal ecology of the Asian bush mosquito adds to our knowledge on the temperature dependence of the species and data could be incorporated in epidemiological and population dynamic modelling.

There is a growing interest in the physiology underpinning heat tolerance of ectotherms and their responses to the ongoing rise in temperature. However, there is no consensus about the underlying physiological mechanisms. According to "the maintain aerobic scope and regulate oxygen supply" hypothesis, responses to warming at different organizational levels contribute to the ability to safeguard energy metabolism via aerobic pathways. At the cellular level, a decrease in cell size increases the capacity for the uptake of resources (e.g., food and oxygen), but the maintenance of electrochemical gradients across cellular membranes implies greater energetic costs in small cells. In this study, we investigated how different rearing temperatures affected cell size and heat tolerance in the fruit fly Drosophila melanogaster. We tested the hypothesis that smaller‐celled flies are more tolerant to acute, intense heat stress whereas larger‐celled flies are more tolerant to chronic, mild heat stress. We used the thermal tolerance landscape framework, which incorporates the intensity and duration of thermal challenge. Rearing temperatures strongly affected both cell size and survival times. We found different effects of developmental plasticity on tolerance to either chronic or acute heat stress. Warm‐reared flies had both smaller cells and exhibited higher survival times under acute, intense heat stress when compared to cold‐reared flies. However, under chronic, mild heat stress, the situation was reversed and cold‐reared flies, consisting of larger cells, showed better survival. These differences in heat tolerance could have resulted from direct effects of rearing temperature or they may be mediated by the correlated changes in cell size. Notably, our results are consistent with the idea that a smaller cell size may confer tolerance to acute temperatures via enhanced oxygen supply, while a larger cell may confer greater tolerance to chronic and less intense heat stress via more efficient use of resources. [ABSTRACT FROM AUTHOR]

Minerals are important components of thousands of enzymes and other compounds in the body. Although the content of minerals in the human body is small, their importance is immense. Edible insects can provide many of these minerals in abundance, and are therefore thought to be a good source of micronutrients. This study dealt with the effect of a rearing temperature and feed on the mineral content and on the content of selected heavy metals in mealworm (Tenebrio molitor). Mealworm larvae were kept at temperatures of 15, 20 and 25°C, and fed with wheat bran, lentil flour and a mixture of both. The types of feed for the experimental groups were chosen purposefully, considering the availability on site, price and especially the impact on the nutrition composition suitable for human. The concentrations of the most significant elements in terms of human nutrition concerns, that is zinc and copper, were determined with inductively coupled plasma mass spectrometry. The results showed that the normality condition was not achieved for Ca, Fe, P and Pb (p<0.05). Therefore, these data were compared using the Kruskal-Wallis method, while ANOVA test was performed for the other elements. There was a statistically significant dependence of the Cd concentration on feed at a constant rearing temperature of 15°C and 25°C over the entire feed change range. The results included a change in Mg over the whole range of monitored values with a change of the rearing temperature and constant feed of lentils-bran,and with a change of feed and constant rearing temperature of 15°C. In contrast, concentrations of Na, P, Ca and Cu over the whole observed range of feed or rearing temperature changes were independent from the variables. With an appropriately chosen rearing temperature and feed, it is possible to obtain mealworm with specific nutritional properties for a target group of consumers. [ABSTRACT FROM AUTHOR]

Understanding how species that follow different life-history strategies respond to stressful temperature can be essential for efficient treatments of agricultural pests. Here, we focused on how the development, reproduction, flight, and reproductive consequences of migration of Cnaphalocrocis medinalis were influenced by exposure to different rearing temperatures in the immature stage. We found that the immature rice leaf roller that were reared at low temperatures (18 and 22 °C) developed more slowly than the normal temperature 26 °C, while those reared at high temperatures (34 °C) grew faster. Female adults from low immature stage rearing temperatures showed stronger reproductive ability than those at 26 and 34 °C, such as the preoviposition period (POP) significantly decreased, while the total lifetime fecundity obviously increased. However, 34 °C did not significantly reduce the reproductive performances of females compared to 26 °C. On the contrary, one relative decreased tendency of flight capacity was found in the lower immature temperature treatments. Furthermore, flight is a costly strategy for reproduction output to compete for limited internal resources. In the lower temperature treatments, after d1-tethered flight treatment, negative reproductive consequences were found that flight significantly decreased the lifetime fecundity and mating frequency of females from low rearing temperatures in the immature stage compared to the controls (no tethered-flight). However, in the 26 and 34 °C treatments, the same flight treatment induced a positive influence on reproduction, which significantly reduced the POP and period of first oviposition (PFO). The results suggest that the experience of relative high temperatures in the immature stage is more likely to trigger the onset of migration, but lower temperatures in the immature stage may induce adults to have a greater resident propensity with stronger reproductive ability.

Ascites syndrome (AS) is a metabolic disorder in fast-growing broilers that is characterized by non-tumult fluid collection in the abdomen. The objective of this study was to evaluate the effects of variable feeding and rearing temperature on AS occurrence in broilers. A total of 360 one-day-old male Ross-308 chicks were assigned to three equal groups (n = 120) fed pellet, crumble or mash diets and within each group, half of birds (n = 60, starting from the 22nd day of age) were reared under two different temperatures: at 23°C (comfort) or at 14°C (cold), respectively. There were six treatments and four replicates including 15 broilers per replicate per treatment. Birds’ growth performances and blood parameters as well the incidence of ascites were assessed. The haematocrit percentage, T3 and T4 hormones activity in pellet-fed group under cold temperature conditions were significantly higher (P .05). Further, feeding of mash diet reduced broilers’ feed consumption per unit of time, especially by level of achieving energy that is reducing the growth and AS.

Wing geometry helps to identify mosquito species, even cryptic ones. On the other hand, temperature has a well‐known effect on insect metric properties. Can such effects blur the taxonomic signal embedded in the wing? Two strains of Aedes albopictus (laboratory and field strain) were examined under three different rearing temperatures (26, 30 and 33 °C) using landmark‐ and outline‐based morphometric approaches. The wings of each experimental line were compared with Aedes aegypti. Both approaches indicated similar associations between wing size and temperature. For the laboratory strain, the wing size significantly decreased as the temperature increased. For the field strain, the largest wings were observed at the intermediate temperature. The two morphometric approaches describing shape showed different sensibilities to temperature. For both strains and sexes, the landmark‐based approach disclosed significant wing shape changes with temperature changes. The outline‐based approach showed lesser effects, detecting significant changes only in laboratory females and in field males. Despite the size and shape changes induced by temperature, the two strains of Ae. albopictus were always distinguished from Ae. aegypti. The present study confirms the lability of size. However, it also suggests that, despite environmentally‐induced variation, the architecture of the wing still provides a strong taxonomic signal. [ABSTRACT FROM AUTHOR]

Larval castes are well known in both sexes of polyembryonic parasitic wasps, in which sterile soldier larvae are clonally produced from a single egg and thousands of reproductive larvae develop into adults. The proportion of soldier larvae in Copidosoma floridanum is first determined genetically in both sexes but subsequently increases in females as a result of environmental disturbances, such as the presence of competitive parasitoids. Because temperature is the most influential environmental factor affecting ectotherms, we hypothesize that an increase in ambient temperature also affects the production of female soldier larvae. Conversely, we hypothesize that there would be no effect of temperature on the production of male soldier larvae. In the present study, we show that heat stress experienced by C. floridanum at an early stage in host development increases the number of female soldier larvae produced during the last instar stage of the host. We also show that rearing at extreme (high and low) temperatures induces an increase in the number of female soldiers produced. The effect of heat stress and ambient temperature on soldier production is found only in females, as is the response to heterospecific competitors. By contrast, no responses are detected in males for either heat stress or ambient temperature. The adaptive effect of these phenomena is not known, although the results of the present study imply the existence of a common physiological cascade that causes an increase in the number of soldier larvae in females. [ABSTRACT FROM AUTHOR]

Abstract Seasonal temperature has a major influence on the infectivity of pathogens and the host immune system. Viral hemorrhagic septicemia virus (VHSV) is one such pathogen that only causes the mortality of fish at low temperatures. This study aims to discover the host defense mechanism and pathway for resistance to VHSV at higher temperatures. We first observed the VHSV infection patterns at low and higher temperatures in fathead minnow (FHM) cells (20 °C and 28 °C) and zebrafish (15 °C and 25 °C). In comparison to the 20 °C infection, FHM cells infected at 28 °C showed decreased apoptosis, increased cell viability, and reduced VHSV N gene expression. In zebrafish, infection at 25 °C caused no mortality and significantly reduced the N gene copy number in comparison to infection at 15 °C. To explore the antiviral infection mechanisms induced by high temperature in vitro and in vivo , the changes in the proteomic profile were measured through UPLC-MSE analysis. ACADL, PTPN6, TLR1, F7, A2M, and GLI2 were selected as high temperature-specific biomarkers in the FHM cell proteome; and MYH9, HPX, ANTXR1, APOA1, HBZ, and MYH7 were selected in zebrafish. Increased immune response, anticoagulation effects, and the formation of lymphocytes from hematopoietic stem cells were analyzed as functions that were commonly induced by high temperature in vitro and in vivo. Among these biomarkers, GLI2 was predicted as an upstream regulator. When treated with GANT58, a GLI-specific inhibitor, cell viability was further reduced due to GLI2 inhibition during VHSV infection at varying temperatures in FHM cells, and the mortality in zebrafish was induced earlier at the low temperature. Overall, this study discovered a new mechanism for VHSV infection in vitro and in vivo that is regulated by GLI2 protein. Graphical abstract Image 1 Highlights • Temperature influences VHSV infection in FHM cells and zebrafish with antiviral effects at higher temperatures. • Comparison of proteomic profiles of both organisms was applied. • Commonly modulated functions in each proteome were hematological system development and inflammatory response. • GLI2 was found to be a main regulator of host antiviral defense against VHSV infection. [ABSTRACT FROM AUTHOR]

Ascites syndrome (AS) is a metabolic disorder in fast-growing broilers that is characterized by non-tumult fluid collection in the abdomen. The objective of this study was to evaluate the effects of variable feeding and rearing temperature on AS occurrence in broilers. A total of 360 one-day-old male Ross-308 chicks were assigned to three equal groups (n = 120) fed pellet, crumble or mash diets and within each group, half of birds (n = 60, starting from the 22nd day of age) were reared under two different temperatures: at 23°C (comfort) or at 14°C (cold), respectively. There were six treatments and four replicates including 15 broilers per replicate per treatment. Birds' growth performances and blood parameters as well the incidence of ascites were assessed. The haematocrit percentage, T3 and T4 hormones activity in pellet-fed group under cold temperature conditions were significantly higher (P < .05) than the other groups. Based on the results, the occurrence of AS under mash-fed regime was less than pellet and crumble dietary groups (P > .05). Further, feeding of mash diet reduced broilers' feed consumption per unit of time, especially by level of achieving energy that is reducing the growth and AS. [ABSTRACT FROM AUTHOR]

To understand the migratory flight behaviors of the loreyi leafworm, Mythimna loreyi Walker (Lepidoptera: Noctuidae), both tethered (flight distance, time, and velocity) and free-flight activity (flight action, duration, and frequency) of adults at different ages, sexes, and temperatures were investigated using computer-controlled insect flight mills and an autonomous flight monitoring system. Tethered flight activity differed significantly among ages and rearing temperature, but not sex. Newly emerged adults (the first day after emergence) displayed the lowest flight time, distance, and speed. However, flight performance increased with age, peaking at 3 d. Relatively strong flight performance was maintained up to 5 d postemergence and then declined significantly by day 6. There was no significant difference in flight performance between sexes for 3-d-old moths. Adults reared as larvae at 24°C averaged significantly longer flight duration and distance than those reared at other temperatures. Both lower and higher rearing temperatures negatively affected tethered flight. Similar results among age and rearing temperature treatments were observed in autonomous free-flight tests. During 12-h free-flight tests, flight activity peaked from 6 to 10 h after beginning of darkness. Free-flight activity of 1- and 6-d-old adults was significantly less than that of 3-, 4-, and 5-d-old adults. Adults reared at 24°C showed significantly greater free-flight action, duration, and frequency than those reared at other temperatures. The results suggest that M. loreyi may be a migratory species. [ABSTRACT FROM AUTHOR]

Abstract: In order to successfully diversify Mediterranean aquaculture, it is necessary to determine optimum culture conditions of potential candidate species such as greater amberjack (Seriola dumerili). Among culture conditions, rearing temperature is a key factor for achieving optimum growth and maintaining fish welfare. However, little is known about the optimum culture conditions of greater amberjack (Seriola dumerili). Thus, the aim of this study was to determine the effect of three different rearing temperatures (17, 22 and 26°C) during 120 days on growth performance, body morphometry, biochemical composition, gut transit and liver morphology of greater amberjack (Seriola dumerili) juveniles. After 120 days of rearing, fish raised at 26°C showed higher (p < .05) body weight and specific growth rate than fish held at lower temperatures, as well as improved feed utilization, protein efficiency and nutrient retention percentages. Fish stomach emptying was faster (p < .05) in fish raised at 26°C than in fish held at 22°C and 17°C. Similar results were obtained for gut transit time, being gut emptying faster (p < .05) in fish reared at 26°C than in fish cultured at lower temperatures. Rearing temperature also induced changes in fish morphology which resulted in a higher (p < .05) caudal propulsion efficiency index for fish reared at 26°C. Based on these results, we conclude that greater amberjack fingerlings perform better at 26°C than at 22°C or 17°C. [ABSTRACT FROM AUTHOR]

In sub-Saharan Africa, urban populations are projected to increase by 115% in the coming 15 years. In addition, economic growth and dietary shifts towards animal source foods have put high pressure and demand on agricultural production. The high ecological footprint of meat and dairy production, as well as high feed costs, prevent the livestock sector from meeting the increasing demand in a sustainable manner. Insects such as the black soldier fly (BSF) have been identified as potential alternatives to the conventionally used protein sources in livestock feed due to their rich nutrient content and the fact that they can be reared on organic side streams. Substrates derived from organic byproducts are suitable for industrial large-scale production of insect meal. Although efficient in waste management and in feed production, BSF larvae are very sensitive to the external environment such as temperature and rearing medium. Therefore, we studied the effect of temperature and substrate type, i.e., brewers’ spent grain (SG) and cow dung (CD), on the development and survival of BSF larvae. Both organic substrates were readily available in Nairobi, Kenya, the location of the experiments. In our experiment, 100 3–5-day-old BSF larvae were placed into containers that contained either SG or CD and further treated at temperatures of 15 °C, 20 °C, 25 °C, 30 °C, and 35 °C. The duration of larval development was recorded, and the prepupae were removed, weighed, and placed individually in separate, labeled, 35-mL plastic cups filled with moist sawdust. After emergence, 10 2-day-old adults (5 males and 5 females) from every replica per substrate were transferred into a cage (40 × 40 × 40 cm) and allowed to mate for 24 h at their respective temperatures. The laid egg batches were collected and counted, and the adult flies’ longevity was recorded. The data were subjected to a two-way analysis of variance (ANOVA) using the general linear model procedure. BSF larvae reared on SG developed faster than those reared on CD; the former also favored higher temperatures for their larval development and emergence into adults. The optimum range was 25–30 °C. With increasing temperatures, the longevity of adult BSF decreased, while the fecundity of females increased. Thus, it is possible to take advantage of the readily available SG waste streams in the urban environments of Kenya to produce BSF larvae-derived livestock feed within a short duration of time and at relatively high temperatures.

Temperature is one of the most important abiotic factors that influences the development and growth of insects. We investigated the effect of temperature on the development of the weevil Eucryptorrhynchus brandti (Harold). The developmental zeros and effective accumulated temperatures for different developmental stages of E. brandti were estimated under variable temperatures in the laboratory. We observed that the developmental zeros of eggs, larvae, and pupae were 15.27 °C, 20.86 °C, and 14.04 °C, respectively, and the effective accumulated temperatures were 81.46°C·d, 293.76 °C·d, and 127.76 °C·d, respectively. The rate of development increased as the temperature increased within a particular temperature range, and temperatures from 30 °C to 31 °C were particularly suitable for E. brandti rearing. Based on these results, we may be able to predict the occurrence of E. brandti, providing a reference for physical control measures targeting adults to effectively reduce oviposition and minimize population expansion. [ABSTRACT FROM AUTHOR]

Several major market operators argue that the current level of knowledge about quality is too scant to justify a switch to a large-scale production of triploid salmon. The aim of the present study was, therefore, to elucidate how rearing conditions (5, 10 and 15 °C) affect the flesh quality of triploid Atlantic salmon ( Salmo salar L., 1.6 ± 0.3 kg). As a reference, diploid salmon kept under equal conditions and with equal genetics were used. The main design discriminant was the holding temperature; increased temperature gave increased blood lactate, rigor index (I r ), drip loss (DL), content of astaxanthin and intensity of redness, but reduced muscle pH, cathepsin activity and fillet lightness. Salmon kept at 10 °C grew the fastest. It is concluded that ploidy gave less variation than temperature. Triploids were characterized by lower blood haematocrit (Hct) and I r , higher DL and collagenase activity, and on average, paler and less yellowish fillets. [ABSTRACT FROM AUTHOR]

Unlike natural selection, phenotypic plasticity allows organisms to respond quickly to changing environmental conditions. However, plasticity may not always be adaptive. In insects, body size and other morphological measurements have been shown to decrease as temperature increases. This relationship may lead to a physiological conflict in ants, where larger body size and longer legs often confer better thermal resistance. Here, we tested the effect of developmental temperature (20, 24, 28 or 32 °C) on adult thermal resistance in the thermophilic ant species Aphaenogaster senilis. We found that no larval development occurred at 20 °C. However, at higher temperatures, developmental speed increased as expected and smaller adults were produced. In thermal resistance tests, we found that ants reared at 28 and 32 °C had half-lethal temperatures that were 2 °C higher than those of ants reared at 24 °C. Thus, although ants reared at higher temperatures were smaller in size, they were nonetheless more thermoresistant. These results show that A. senilis can exploit phenotypic plasticity to quickly adjust its thermal resistance to local conditions and that this process is independent of morphological adaptations. This mechanism may be particularly relevant given current rapid climate warming. [ABSTRACT FROM AUTHOR]

Rodent models raised at environmental temperatures of 21–22 °C are increasingly switched to thermoneutral housing conditions in adulthood to better capture human physiology. We quantified the developmental effects of rearing mice at an ambient temperature of 22 °C vs. 30 °C on metabolic responses to cold and high fat diet (HFD) in adulthood. Mice were reared from birth to 8 weeks of age at 22 °C or 30 °C, when they were acclimated to single housing at the same temperature for 2–3 weeks in indirect calorimetry cages. Energy expenditure attributable to basal metabolic rate, physical activity, thermic effect of food, and adaptive cold- or diet-induced thermogenesis was calculated. Responses to cooling were evaluated by decreasing the ambient temperature from 22 °C to 14 °C, while responses to HFD feeding were assessed at 30 °C. Influences of rearing temperature on thermogenic responses that emerge over hours, days and weeks were assessed by maintaining mice in the indirect calorimetry cages throughout the study. At an ambient temperature of 22 °C, total energy expenditure (TEE) was 12–16% higher in mice reared at 22 °C as compared to 30 °C. Rearing temperature had no effect on responses in the first hours or week of the 14 °C challenge. Differences emerged in the third week, when TEE increased an additional 10% in mice reared at 22 °C, but mice reared at 30 °C could not sustain this level of cold-induced thermogenesis. Rearing temperature only affected responses to HFD during the first week, due to differences in the timing but not the strength of metabolic adaptations. Rearing at 22 °C does not have a lasting effect on metabolic adaptations to HFD at thermoneutrality, but it programs an enhanced capacity to respond to chronic cold challenges in adulthood. These findings highlight the need to consider rearing temperature when using mice to model cold-induced thermogenesis. • Moving adult mice to thermoneutrality ignores effects of temperature in early life. • Continuous indirect calorimetry to assess acute and chronic thermogenic responses. • Rearing at 22 °C programs enhanced responses to chronic, but not acute, cold. • Rearing at 22 °C doesn't affect susceptibility to high fat diet induced obesity. [ABSTRACT FROM AUTHOR]

Water temperature is a key factor in aquaculture production of the commercially valuable sea cucumber Holothuria scabra . Knowledge is scarce about actual energetic costs that can be associated with internal acclimatization processes as a response to thermal extremes. In the present study changes in cellular energy allocation, oxygen consumption rate and energy related enzymes' activity (IDH and LDH) were measured in juvenile H. scabra , held at different temperatures: 21, 27 and 33 °C. The results showed that the steady temperature change (1 °C/day) to both temperature treatments, until reaching the testing temperatures (day 0), clearly affected cellular energy consumption and available energy reserves, measured in the respiratory tree and muscle tissue, respectively. However, 15 and 30 days after acclimation, the initial differences in cellular energy allocation between treatments decreased. In contrast to the variations measured in cellular energy allocation, oxygen consumption was highest at 33 °C and lowest at 21 °C at all three measurement times. Moreover, a significant positive correlation between oxygen consumption rate and temperature was detected at day 15 and day 30. Likewise, a shift from anaerobic to aerobic energy metabolism, indicated by changes in LDH and IDH activities, was observed in the animals from the warm temperature treatment. Results imply that juvenile H. scabra were able to recover from initial disturbances in energy balance, caused by the incremental temperature change of ± 6 °C. Over the experimental period of 30 days, elevated temperature did however, lead to a metabolic shift and more efficient energy turnover, indicated by changes in oxygen consumption rate, LDH and IDH. The synergy of cellular energy allocation and oxygen consumption proved to be a viable indicator to assess the capability of sea cucumbers like H. scabra to cope with extreme temperature conditions. Surprisingly, juvenile H. scabra were able to sustain their energy balance and oxygen consumption rate within the homeostatic range, even at 33 °C. Thus, we assume that rearing temperatures of 33 °C might be possible, which could improve aquaculture production of H. scabra . However, further research is required to understand the mechanisms and effects of acclimation under aquaculture conditions. Statement of relevance The sea cucumber H. scabra is considered a promising aquaculture candidate in the tropics. The commercial interest in H. scabra has led to a great number of attempts to culture this species e.g. in Madagascar, Tanzania, India and Indonesia, where the farming of this species also showed a great potential to increase the livelihood of the local community. Although, considerable research effort has been put into the advancement of the production cycle, fundamental knowledge, e.g. on physiological adjustments due to sub-optimal rearing conditions, remains scarce for H. scabra . Water temperature has been identified as crucial factor, determining production efficiency. In our manuscript we introduce an innovative approach, for the assessment of shifts in the energy budget as well as in metabolic pathways, to detect thermal stress in juvenile H. scabra . Our results show that the combined application of cellular energy allocation (CEA) and measurement of the oxygen consumption rate (OCR) as well as the activity of two metabolic key enzymes: iso-citrate dehydrogenase (IDH) and lactate dehydrogenase (LDH), is a strong analytical tool to evaluate whole animal homeostasis under thermal extremes. To our knowledge this is the first study in which the method of CEA was optimized for the application on isolated muscle and respiratory tree tissue of a sea cucumber, like H. scabra . Hence, our results provide original insights into the thermal acclimation physiology of H. scabra, which provides crucial knowledge for setting up optimal culture conditions for this highly valuable aquaculture candidate. Moreover, our results show that juvenile H. scabra were strongly affected by rapid temperature changes, exhibiting distinct differences in metabolic adjustments as response to short-term cold and warm acclimation, but were able to restore homeostatic conditions at constant cold and warm temperature extremes. Concerning aquaculture practices, these findings imply that CEA might be a good condition indicator to evaluate the overall metabolic status in sea cucumbers. Moreover, rapid temperature fluctuations seem to provoke much higher energetic costs in juvenile H. scabra than constant extreme temperature conditions, which is important to consider in daily management practices. The OCR revealed an enhanced metabolism at warmer temperature conditions, throughout the entire experimental period. Likewise, the warm exposed animals were shifting their energy turnover from a more anaerobic to a more aerobic state, indicated by changes in LDH and IDH activities, and showed increased foraging activity at all times. The combined outcome of CEA, OCR and activities of energy metabolism related enzymes indicates, that the increased metabolic activity in juvenile H. scabra , as response to warmer temperature, was well within the homeostatic range. Thus, contrary to our expectations, a rearing temperature of up to 33 °C might presumably be favourable for the aquaculture of H. scabra. [ABSTRACT FROM AUTHOR]

Larval amphibians are particularly likely to encounter variation in rearing temperature and resource availability due to variation in aquatic breeding habitats. In this study, plasticity in growth rates, larval mass, larval period, and size at metamorphosis were examined in Rana kukunoris Nikolskii, 1918 under different combinations of temperature and food level. Larval period and larval body mass was sensitive to food level, and varied with temperature. Tadpoles metamorphosed at an older age at low temperature than those reared at warm temperature. Food level was a significant affect on larval period at low temperature, but not at warm temperature. Mass was heavier for tadpoles reared at low temperatures than those reared at warm temperatures. The effect of food level depended on temperature, because larvae reared at low temperature that were offered a high food level achieved a larger size than larvae offered a low food level, but this did not occur at warm temperature. Therefore, we suggest that high food availability at low temperature prolonged developmental periods, thus larvae are larger as metamorphs than those reared at warm temperatures. [ABSTRACT FROM AUTHOR]

This study investigated the modulating effect of temperature variation on the metabolic status and growth performance of tropical freshwater fish, Labeo rohita, when reared with starch-based gelatinized (G) or non-gelatinized ( NG) diet. Fish were either maintained at ambient water temperature (26 °C) or exposed to 32 °C for 1 week, and then subjected to 26 °C for 4 weeks. Both groups were fed with isoproteinous (300 g kg−1) diets containing G or NG starch. A significant interaction was evident between increased metabolic activity due to the short-term exposure to higher temperature and starch type on growth performance, feed efficiency and protein retention. Dietary starch type and water temperature interactions were more effective in modulating the hepatic glucokinase and pyruvate kinase responses than that of hexokinase. Hepatic aspartate amino transferase and alanine amino transferase activities were augmented at low temperature in NG starch fed group. Overall, our findings indicate that enzyme activities are enhanced due to the short-term exposure to higher temperature (32 °C). This elevated temperature lasted for 3 weeks after exposure during which NG starch tended to support the growth. [ABSTRACT FROM AUTHOR]

The gut microbiomes of fish play important roles in host development, digestion and health. Evidence suggests that abiotic factors, such as diet and rearing temperature, could affect fish gut microbiota. In this study, the effect of dietary short-chain fructooligosaccharides (sc FOS) on turbot intestinal health, microbiota and digestive enzymes was investigated at two rearing temperatures: 15 and 20 °C. Four practical diets were supplemented with sc FOS at 0, 5, 10 and 20 g kg−1. sc FOS did not affect fish performance. PCR- DGGE did not show differences in bacterial profiles between dietary treatments; however, the number of operational taxonomic units, richness and diversity were higher at 20 °C. Enzyme activities in the foregut were not affected by rearing temperature, while in the hindgut, enzyme activities were higher at 15 °C. Total alkaline protease, α-amylase and lipase activities in the foregut were higher in fish fed 20 g kg−1 sc FOS. Prebiotic supplementation had no effect on hindgut α-amylase activity, while lipase activity of fish reared at 20 °C was higher in fish fed diet with 5 g kg−1 sc FOS. No differences were observed in intestinal morphology. This was the first study to simultaneously evaluate the effect of dietary prebiotic level and rearing temperature on fish intestinal microbiota and health. [ABSTRACT FROM AUTHOR]

The techniques and protocols used to successfully capture, transport and breed Arctic cod Boreogadus saida, as well as to rear their larvae through to adulthood are summarized. Breeding B. saida will increase the opportunity to study this fish species, which is a critical part of the Arctic food web. [ABSTRACT FROM AUTHOR]

The lower termite, Coptotermes formosanus Shiraki, is an important model species for studying the dual cellulolytic system of termites. The effect of rearing temperature on the interaction between the intestinal symbiont community and the host in lignocelluloses digestion was investigated by assaying the activity and gene expression of cellulase, and monitoring the population size of intestinal protozoan community, which was followed by rearing C. formosanus at a temperature gradient (15–37 °C) for 3 d. The results showed that the rearing temperature of C. formosanus had a much greater impact on cellulase activity and gene transcription of the intestinal symbiont than on the host. The transcriptional variations of endogenous and symbiotic cellulase genes presented mutual complement and restrained when C. formosanus living in high temperature environment (32 and 37 °C). Additionally, the optimum survival temperature of Pseudotrichonympha grassii Koidzumi (22 °C) was found lower than that of Holomastigotoides mirabile Koidzumi (28 °C) and Spirotrichonympha leidyi Koidzumi (28 °C).The optimum rearing temperature for cellulase activity and protozoan survival of C. formosanus was found much lower than its optimum temperature for feeding. These findings provide a novel glimpse into host-symbiotic mutualism in lower termite digestion. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the strategy to mitigate the immunosuppressive and oxidative stress effect of gelatinized starch in fingerling of Labeo rohita . Fingerlings were either maintained at ambient water temperature (26 °C) or exposed to 32 °C for one week and then subjected to 26 °C for four weeks. Both groups were fed with isoproteinous (30% crude protein) diets containing gelatinized (G) or non-gelatinized (NG) starch. After 5 weeks of feeding trial, fingerlings were challenged by Aeromonas hydrophila and survival rate was recorded for the next 7 days. Serum cortisol and glucose content was significantly ( p < 0.05) higher in G starch fed group and decreased with the increase in temperature from 26 to 32 °C, which was consistent for next four week after decrease in temperature from 32 to 26 °C. Lower respiratory burst activity and serum total protein and globulin content in G starch fed group at 26 °C significantly ( p < 0.05) increased after elevation of temperature from 26 to 32 °C and levelled off to NG starch fed group. Liver superoxide dismutase (SOD) and catalase (CAT) activity of G starch fed group was significantly higher in group reared at 32 °C compared to 26 °C. After challenge, fish fed G starch showed lower survival rate than that of fish fed NG starch. Subsequently, exposure of elevated temperature (32 °C) for one week significantly increased the survival rate of G starch fed group and levelled off to NG starch fed group. The results of this study indicated that dietary G starch may cause metabolic stress of fingerling L. rohita , as might consequently lead to the decrease antioxidant abilities, depressed immunity and reduced resistance to A. hydrophila infection. Subsequently, exposure of elevated temperature (32 °C) for one week mitigate immunosuppressive and oxidative stress effect of dietary G starch. [ABSTRACT FROM AUTHOR]

The effect of water temperature on the growth of juvenile snow crabs Chionoecetes opilio (Fabricius, 1788) was investigated in laboratory culture experiments. Laboratory-born juveniles were cultured from instar I to VIII at four temperatures (approximately 1, 3, 5 and 8°C). The growth indices (size increments at moulting in mm and in % of premoult carapace width) were significantly higher in crabs reared at 5°C than in those reared at other temperatures. The relationship between the mean temperature (T ) and intermoult period (D) of each instar was described by the heat summation theory equation: D = K/(T --α). The thermal constant K is the summation of the effective temperature for development (above the threshold temperature, α) up to a selected biological end point. The thermal constant tended to increase and the threshold temperature tended to decrease with increasing mean premoult carapace width of each instar, reaching asymptotes of 1573 day-degrees and -4.7°C, respectively. Size- and temperature-dependent growth models were developed for snow crab juveniles. [ABSTRACT FROM AUTHOR]

The present work examined the short- and long-term effects of three rearing temperatures on protein metabolism and growth trajectories of Senegalese sole larvae using 14C-labelled Artemia protein as feed. A first feeding trial was performed on larvae reared at 15, 18 and 21 °C (at 26, 17 and 14 days post-hatching (dph), respectively) and a second trial conducted on post-larvae after transfer to the same rearing temperature (~20 °C) (49, 35 and 27 dph, in larvae initially reared at 15, 18 and 21 °C, respectively). Temperature greatly influenced larvae relative growth rate (RGR) and survival, since growth at 15 °C was severely depressed. Protein digestibility and retention was highest at 18 °C during the first trial (85.35 ± 1.16 and 86.34 ± 2.33 %, respectively). However, during the second trial, post-larvae from 15 °C had the highest feed intake and protein digestibility (3.58 ± 1.54 and 75.50 ± 1.35 %, respectively), although retention was similar between treatments. Furthermore, after transfer to 20 °C larvae from 15 °C experienced compensatory growth, which was observed until 121 dph, and confirmed by RGR values, which were significantly higher at 15 ºC than at 21 ºC or 18 ºC. Results from the present study show that Solea senegalensis larval development, survival and protein digestion and retention are highly affected by thermal history. [ABSTRACT FROM AUTHOR]

The present study examined the influence of early-rearing temperature—which favors the development of male-dominant or female-dominant populations—in European sea bass Dicentrarchus labrax on haemal lordosis and growth performance until harvest time (mean body weight>400g). European sea bass were reared at 15 or 20°C from egg to metamorphosis (~17mm in total length), which lasted for 66 and 55days post spawning (dps), or 990 and 1100°C-days, respectively. Thereafter, rearing until harvest time (715dps) followed a common temperature regime, ranging between 14.5°C in February and 26.5°C in August. As expected from previous studies, the effect of early-life rearing temperature was significant on mean (±SEM) sex ratio (78±2% females at 15°C vs. 29±2% females at 20°C) and there was a highly significant (P<0.01) growth advantage in favor of the 20°C fish at the end of the first year. However, there was no significant difference in body weight between the two temperature groups by harvest time, indicating the expression of compensatory growth in the 15°C group. The mean occurrence of haemal lordosis incidence was evaluated using X-rays at the end of the nursery phase (145dps) and was shown to be significantly higher in the 20°C group (90±0.4%) compared to the 15°C group (41±0.8%). The occurrence of haemal lordosis upon external image evaluation at harvest time decreased to 0% in the 15°C group compared to 36±7% in the 20°C group. Almost half of these latter fish with haemal lordosis were considered unmarketable due to heavy deformation. These findings demonstrated that rearing European sea bass at low temperatures during early life can result in significant gains for aquaculture industry, through increases in female proportion—and therefore growth performance—and reductions in skeletal abnormalities. The study also demonstrated that even fish with heavy haemal lordosis could grow as well as normal fish, thus competing for food with normal fish and resulting in financial loss for the industry due to their unmarketability. [ABSTRACT FROM AUTHOR]

Effects of different rearing temperatures (16, 21 and 26°C) on growth, metabolic performance and thermal tolerance of juvenile sea cucumber A postichopus japonicus (initial body weight 7.72 ± 0.96 g, mean ± SD) were investigated in this study. During the 40-day experiment, growth, metabolic performance, food intake and energy budget at different reared temperatures were determined. Sea cucumbers rearing at 16°C obtained better growth (final body weight 11.96 ± 0.35 g) than those reared at 21 (10.33 ± 0.41 g) and 26°C (8.31 ± 0.19 g) ( P < 0.05), and more energy was allocated for growth at 16°C (162.73 ±11.85 J g−1 d−1) than those at 21(79.61 ± 6.76 J g−1 d−1) and 26°C (27.07 ± 4.30 J g−1 d−1) ( P < 0.05). Critical thermal maxima ( CTmax) values of juvenile sea cucumbers reared at 16, 21 and 26°C were 33.1, 34.1 and 36.6°C, respectively, and the upregulation of hsps in sea cucumbers reared at 26°C was higher than those acclimated at lower temperatures (16 and 21°C), indicating that temperature acclimation could change the thermal tolerance of the sea cucumber, and CTmax and hsps were sensitive indicators of the sea cucumber's thermal tolerance. [ABSTRACT FROM AUTHOR]