Effects Of Temperature Manipulation Research Articles

Towards the Control of the Reproduction of the Yellow Clam Amarilladesma mactroides (Reeve, 1854) in Captivity: Effects of Different Stimuli on the Spawning of Laboratory-Conditioned and Unconditioned Breeders

The effects of temperature manipulation, addition of sperm solution, and exposure to alkalized pH and/or hydrogen peroxide (H2O2) as possible spawning inducers in laboratory-conditioned and unconditioned adults of the yellow clam (Amarilladesma mactroides) were evaluated. In three trials, clams were laboratory-conditioned for 14 days and exposed to thermal shocks (from 20 °C to 23–29 °C), while clams from three additional trials were not conditioned but acclimatized for 45 min before spawning induction. Although conditioning advanced gonad maturity and increased the condition factor, none of the thermal treatments triggered spawning in these first trials. Histological analysis indicated that the gonads of conditioned clams were not mature. Alternatively, unfertilized and fertilized eggs, and larvae were observed after unconditioned clams were induced to spawn. The gonads of unconditioned clams were in an advanced stage of maturity. Exposure to temperature shocks, alone or in combination with the addition of sperm solution and with H2O2, resulted in spawning. Clams exposed to H2O2 kept their valves closed and had a high mortality rate. Temperature manipulation is the most promising stimulus to induce spawning in A. mactroides. As the success of conditioning depends on the stage of gonadal development at the time of capture in the wild, a period longer than 14 days may be necessary.

Effects of temperature manipulation on gamete development and reproductive activity in the farmed catfish Lophiosilurus alexandri

Temperature is a critical factor for fish management, especially during breeding season. This study evaluated gametogenesis and gonadal maturation in the catfish Lophiosilurus alexandri under farming conditions in two temperatures. The fish were divided in the following experimental groups: (S0) control group, before starting the experiment, (S1) 30 days at 23 °C, (S2) 70 days at 23 °C, (S3) 30 days at 27 °C, and (S4) 70 days at 27 °C. Gonad, liver, and blood samples were obtained to analyze reproductive and health parameters. In females, increased gonadosomatic index (GSI) was associated with a decreased proportion of perinucleolar follicles and increased diameter of vitellogenic follicles in S4. Postovulatory follicles were found only in fish kept at 27 °C, whereas atretic follicles were more frequent at 23 °C. In S4, females had higher hepatic levels of vitellogenin and lower levels of zona radiata proteins. In males, a lower proportion of spermatogonia was found at 27 °C (S4), whereas GSI and proportions of spermatocytes, spermatids, and spermatozoa were similar among the groups. Levels of cortisol were higher in females of group S3. Plasma 17β-estradiol, 11-ketotestosterone and 17α-hydroxyprogesterone were significantly higher in S4. Hematocrit, erythrocytes, and glucose were higher at 27 °C. Together, the present study indicate that exposure of L. alexandri to 27 °C provides suitable conditions for germ cell development and gonadal maturation in captivity, promotes increase of sex steroids, follicular growth, and oocyte maturation, with onset of ovulation occurring at 30 days. At 23 °C, spermatogonia proliferation is favored in males, but it cannot be recommended for stimulating female maturation of L. alexandri in fish farming.

Effect of temperature manipulation during incubation on body weight, plasma parameters, muscle histology, and expression of myogenic genes in breast muscle of embryos and broiler chickens from two commercial strains

ABSTRACT 1. This study evaluated the effect of a higher incubation temperature on body weight, plasma profile, histology and expression of myogenin (MYOG), insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor A (VEGFA) genes in breast muscle of embryos and broilers from two commercial strains. 2. A total of 784 eggs from Ross 308 and Cobb 500 broiler breeder flocks were used. Half of the eggs per strain were incubated at control temperature (37.8°C), whereas the other half were exposed to heat treatment (HT) of 38.8°C between embryonic day (ED) 10 and 14, for 6 h/day. Embryos and chicks were sampled on ED 19 and at hatch. A total of 480, one-day-old chicks per strain and incubation temperature were reared up to 42 d post-hatch. 3. The HT increased hatch weight of Ross chicks and 42-d body weight of broilers from both strains. Lower plasma triacylglycerol levels were measured for HT embryos and broilers on ED 19 and 42 d post-hatch, respectively. HT reduced plasma T3 levels in Ross embryos and broilers for the same periods. Hepatic TBARS concentrations were elevated by HT compared to the control incubation. 4. The HT reduced breast muscle VEGFA gene expression of Cobb embryos on ED 19, whereas expression was stimulated in day-old chicks. At 42 d post-hatch, fibre area was increased by HT regardless of strain. Compared to the control incubation, HT increased the breast yield of Ross broilers and leg yield of Cobb. Ross-HT broilers had a higher pH at 24 h after slaughter and better water holding capacity than Cobb-HT broilers. 5. These results suggested that HT increased body weight, fibre area, IGF-I gene expression and lowered plasma triacylglycerol levels of broiler chickens from both strains at 42 d. However, HT influenced the expression of VEGF-A and MYOG genes and meat quality differently between the broiler strains.

Abstract 104: Metabolic Effect of Temperature Manipulation in Healthy Individuals

Introduction: Temperature manipulation to decrease metabolism is commonly after acute brain injury. Preclinical data suggest metabolism decreases 7-8% for each degree C drop in core temperature. We hypothesized similar results would be found in healthy individuals. Methods: Following informed consent and physical screening, we administered a 1mcg/kg bolus of dexmedetomidine followed by 20cc/kg of cold (4C) saline bolus. We cooled subjects using surface pads (emcools (Austria)). Dexmedetomidine infusion was titrated to effect (max dose <1.5mcg/kg/hr). We recorded vital signs, Richmond Agitation Sedation Scale, Bedside Shivering Assessment Scale and sensation of cold every 15 minutes. We measured resting metabolism at baseline and after each 1 C decrease in temperature thereafter using indirect calorimetry and a ventilated canopy system. We analyzed data using analysis of variance. Results: Median age in the 9 enrolled subjects was 30 (SD 10) years and most (78%) were male. Median height was 173 (IQR 168, 180) cm and median weight was 77 (IQR 72, 83) kg. Baseline VO2 was 3.4 (IQR 3.0, 3.8) ml/kg/min and baseline energy expenditure was 1692 (IQR 1579, 1845) kcal/day. Both VO2 and energy expenditure decreased with core temperature (p=0.017 and p=0.027) (Table). Conclusion: Metabolic rate decreases with core temperature manipulation. The largest change occurs between 37C and 36C with smaller changes thereafter.

Warming intensify CO2 flux and nutrient release from algal wrack subsidies on sandy beaches.

Algal wrack subsidies underpin most of the food web structure of exposed sandy beaches and are responsible of important biogeochemical processes that link marine and terrestrial ecosystems. The response in decomposition of algal wrack deposits to global warming has not been studied in ocean-exposed sandy beaches to date. With this aim, passive open top chambers (OTCs) were used to increase soil temperature within the range predicted by the IPCC for western Europe (between 0.5 and 1.5°C), following the hypothesis that the biogeochemical processing of macroalgal wrack subsidies would accelerate in response to temperature increase. The effect of temperature manipulation on three target substrates: fresh and aged macroalgae, and bare sand, was tested. Results indicated that a small warming (<0.5°C) affected the wrack decomposition process through traceable increases in soil respiration through CO2 flux, inorganic nutrients within the interstitial environment (N and P), sediment organic contents measured through the amount of proteins and microbial pool through the total soil DNA. The different responses of soil variables in the studied substrates indicated that the decomposition stage of stranded macroalgae influences the biogeochemical processing of organic matter in sandy beaches. Thus, CO2 fluxes, releases of organic and inorganic nutrients and microbial activity intensify in aged wrack deposits. Our results predict that expected global warming will increase the release of inorganic nutrients to the coastal ocean by 30% for the N (21Gg/year) and 5.9% for P (14 Gg/year); that increase for the flow of C to the atmosphere as CO2 was estimated in 8.2% (523Gg/year). This study confirms the key role of sandy beaches in recycling ocean-derived organic matter, highlighting their sensitivity to a changing scenario of global warming that predicts significant increases in temperature over the next few decades.

Chick embryogenesis: a unique platform to study the effects of environmental factors on embryo development.

Bird embryogenesis takes place in a relatively protected environment that can be manipulated especially well in domestic fowl (chickens) where incubation has long been a commercial process. The embryonic developmental process has been shown to begin in the oviduct such that the embryo has attained either the blastodermal and/or gastrulation stage of development at oviposition. Bird embryos can be affected by "maternal effects," and by environmental conditions during the pre-incubation and incubation periods. "Maternal effects" has been described as an evolutionary mechanism that has provided the mother, by hormonal deposition into the yolk, with the potential to proactively influence the development of her progeny by exposing them to her particular hormonal pattern in such a manner as to influence their ability to cope with the expected wide range of environmental conditions that may occur post-hatching. Another important aspect of "maternal effects" is the effect of the maternal nutrient intake on progeny traits. From a commercial broiler chicken production perspective, it has been established that greater cumulative nutrient intake by the hen during her pullet rearing phase prior to photostimulation resulted in faster growing broiler progeny. Generally, maternal effects on progeny, which have both a genetic and an environmental component represented by yolk hormones deposition and embryo nutrient utilization, have an important effect on the development of a wide range of progeny traits. Furthermore, commercial embryo development during pre-incubation storage and incubation, as well as during incubation per se has been shown to largely depend upon temperature, while other environmental factors that include egg position during storage, and the amount of H2O and CO2 lost by the egg and the subsequent effect on albumen pH and height during storage have become important environmental factors to be considered for successful embryogenesis under commercial conditions. Manipulating environmental temperature during the period of egg storage, during the intermediate pre-incubation period, and incubation period per se has been found to significantly affect embryo development, hatching progress, chick quality at hatching, and chick development post-hatching. These temperature manipulations have also been shown to affect the acquisition of thermotolerance to subsequent post-hatching thermal challenge. This chapter will focus on: a. "maternal effects" on embryo and post-hatching development; b. environmental effects during the post-ovipositional period of egg storage, the intermediate pre-incubation period, and incubation period per se on chick embryogenesis and subsequent post-hatching growth and development; and c. effects of temperature manipulations during the pre-incubation and incubation periods on acquisition of thermotolerance and development of secondary sexual characteristics in broiler chickens.

Abstract 2408: Electrophysiologic Monitoring Of Neurological Recovery With Temperature Manipulation After Cardiac Arrest In Rats

Background Therapeutic hypothermia after cardiac arrest (CA) improves survival and functional outcomes, while hyperthermia is harmful. The optimal tool for tracking the effect of temperature manipulation on recovery of cortical electrical function has not been elucidated. Previously, we demonstrated that good neurological recovery is associated with higher relative electroencephalographic (EEG) entropy, measured by information quantity (IQ). Methods We investigated the effect of temperature manipulation on neurological recovery after asphyxial CA in a rodent model using quantitative EEG (qEEG). Twenty-four rats were evenly divided into 3 groups (n=8 per group, randomly assigned), based on 6 hours of hypothermia (T=33°C), normothermia (T=37°C) or hyperthermia (T=39°C) immediately after resuscitation from 7-minute asphyxial CA. Temperature was maintained using surface cooling and warming. Neurological recovery was evaluated using serial Neurological Deficit Score (NDS) calculation. Results Greater recovery of IQ was found in rats treated with hypothermia (0.74±0.03), compared to normothermia (0.60±0.03) and hyperthermia (0.56±0.03) (p&lt;0.001). qEEG analysis at different intervals demonstrated a significant separation of IQ scores between the groups only within the first 2 hours of resuscitation (p&lt;0.01). The 72-hour NDS of the hypothermia group (74, 61–74; Median, 25 th –75 th percentile) was also significantly improved compared to the normothermia (49, 47– 61) and hyperthermia (43, 0 –50) groups (p&lt;0.001). The IQ values correlated strongly with the 72-hour NDS as early as 30 minutes after resuscitation (Pearson correlation 0.735, 2-tailed significance p=0.01) and maintained a significant association throughout the 72-hour experiment. Conclusions Early qEEG was sensitive to the benefit of hypothermia as well as the harmful effect of hyperthermia post-CA and predicted neurological recovery at 72 hours.

The effect of the rate and onset of temperature increase on spawning of the periwinkle, Littorina littorea (L.)

Littorina littorea (L.) from a rocky shore on Pendleton Island, New Brunswick, Canada were experimentally manipulated to determine the effect of temperature on spawning as a possible means of explaining the differential timing of settlement observed in two consecutive years. Variation in the rate or onset of temperature increase influenced the duration of spawning. Under conditions simulating shore temperature, spawning continued for 17–21 wk. An accelerated rate of temperature increase reduced spawning to a period of 8–14 wk. When the rate of temperature increase was normal but the onset of temperature increase was delayed, spawning was extended to 21–24 wk. The number of embryos released from individual females increased in direct proportion to the spire height. The number of embryos released in the accelerated and delayed treatments depended on the spire height of the female. For smaller females (spire height <17 mm) there was no effect of temperature manipulation. However, for the larger, more fecund, females significant differences from the control were observed in the number of embryos released under conditions of accelerated temperature. No significant differences were evident between the control and the delayed temperature increase experiment. In L. Littorea the rate of temperature increase as opposed to the timing of the increase has a more pronounced effect on the reproductive output.

Effect of temperature manipulation during storage and ripening on firmness, extractable juice and woolliness in nectarines

‘Independence’ nectarines were stored at — 0.5°C for three or four weeks or at 3°C for four weeks or kept at room temperature for 18 h prior to storage for four weeks at -0.5°C. After cold storage, fruit from all treatments was ripened at 10°, 15°or20°C. In all treatments the percentage woolly fruit initially increased to high values and thereafter decreased with further ripening. The rate of increase and decrease in woolliness depended on the ripening temperature. A storage period of four weeks at — 0.5°C resulted more woolliness during subsequent ripening. Woolliness persisted longer after a four-week cold storage period than after a three-week one. When fruit was delayed at room temperature prior to cold storage, woolliness generally developed earlier and to a lesser extent during ripening. At all ripening temperatures initial storage at 3°C resulted in most woolliness extending over the longest period. In addition, browning of the meso- carp tissue occurred only in fruit cold stored at 3°C.-The delay ...

Reproductive Response ofPenaeus stylirostristo Temperature Manipulation

AbstractThe effect of temperature manipulation on the reproduction ofPenaeus stylirostriswas investigated as a possible method for increasing larval production. Six 3.66 m diameter black tanks were stocked with unilaterally eyestalk enucleated females and intact males. Temperature was designed to vary between 20 and 28 C at a rate of 2 C per day in the “Fast” treatment and 2 C per week in the “Slow” treatment; upper and lower temperatures were maintained for 10 days before another cycle was initiated. In the “Ambient” treatment, temperature averaged 27.8 ± 0.9 C.During the 105 day study maturation, mating and larval production were highest in the Ambient tanks. Temperature manipulation as tested in the Fast and Slow treatments did not produce any burst of mating and spawning activity at the upper ends of the cycles to compensate for the steady production in the Ambient group. Thus, the temperature regimes examined did not afford any practical advantage.The effect of temperature on mating was marked. In the Slow treatment which most closely mimicked natural seasonal temperature change, mating began initially when the temperature increased to 25 C. Throughout the study mating occurred more frequently at the higher temperatures, and these results suggest that the optimal temperature range was 27–29 C for reproduction. However, the shrimp did mate at all temperatures encountered. It is notable that this tropical species can successfully reproduce at temperatures as Iow as 20 C.

Conformation of a Single Mitochondrion in the Trypomastigote Stage of Trypanosoma cruzi

embryo exhibits a degree of innate resistance against T. lewisi and T. musculi that is based upon the physiological state of the experimental host. Resistance was abrogated when the embryo was incubated at a suboptimal 33 C temperature rather than at 37 C. Exposure to the lower temperature could be expected to alter any of several physiological factors that might create improved conditions for parasite survival. Characteristics of T. musculi infection in embryos at 33 C and in mice compromised by reticuloendothelial blockade are similar, i.e., presence of numerous epimastigote forms and variable trypanosome length (Taliafero and Pavlinova, 1936, J. Parasitol. 22: 29-41), suggesting that direct or indirect inhibition of phagocytic function may contribute to increased embryo susceptibility. Results of our study indicate that the chick embryo can be useful for studies of the effects of temperature manipulation on resistance against infectious agents. The embryo essentially represents a self-contained, sterile system in which factors such as concurrent infection, environmental stress, and specific immunological responsiveness may have less influence on direct evaluation of temperature effects than in young or adult animals. We are grateful to Drs. J. P. Farrell and Martha Runey for providing T. musculi and T. lewisi, respectively. i ition of phagocytic function may conto increased embryo susceptib lity.