Effect of allozyme heterozygosity on basal and induced levels of heat shock protein (Hsp70), in juvenile Concholepas concholepas (Mollusca)

Organisms cope physiologically with extreme temperature by producing heat shock proteins (HSPs). Expression of Hsp70 enhances thermal tolerance and represents a key strategy for ectotherms to tolerate elevated temperature in nature. Synthesis of these proteins, together with other physiological responses to elevated temperatures, increases energy demands. A positive association between multiple and single locus heterozygosity (MLH and SLH, respectively) and individual fitness has been widely demonstrated. In molluscs, MLH can decrease routine metabolic rates and improve energetic status. Juvenile Concholepas concholepas live in the intertidal zone and are constantly exposed to temperature fluctuations. Thus, these young individuals are exposed both to thermal risks and the large metabolic costs required to cope with thermal stress. We evaluated the effects of allozyme MLH and SLH on basal (control animals) and induced (stressed animals) levels of the Hsp70 in juveniles C. concholepas. Juveniles (n = 400) were acclimated at 16 °C for 2 weeks; then 100 animals were exposed to 24 °C (stress) and 100 were kept at 16 °C (control) for 2 and 7 days. The variability of 20 loci was analyzed by starch gel electrophoresis. For SLH effects we used 7 polymorphic loci. We quantified expression of Hsp70 by Western blot analyses. Hsp70 expression increased markedly (~ 90%) with temperature. We found a positive association between MLH and basal and induced levels of Hsp70 in the 2-day exposure experiment. Regardless of temperature, Hsp70 levels increased with MLH (r² = 0.7 and 0.9, for basal and induced levels, respectively) reaching maximal levels in juveniles with intermediate and high MLH levels (2 and 3 loci), and decreasing slightly (but not significantly) in juveniles with highest MLH (≥ 4 heterozygous loci). However, after 7 days of exposure to thermal stress, less heterozygous juveniles attained the same levels of Hsp70 than more heterozygous juveniles. Given the faster increment of Hsp70 in C. concholepas juveniles with intermediate-high levels of MLH, these individuals could be less affected by thermal stress in the intertidal zone. We found an association between specific loci genotype and higher Hsp70 levels (basal or induced). In comparison to homozygous juveniles, heterozygous juveniles for several loci showed higher Hsp70. However, these associations were not for the same loci in juveniles exposed to high temperature for 2 and 7 days. This suggests genotypic variation at some allozyme loci could be more important in the period of initial response to high temperature and others can be more important in the response to the chronic temperature stress.     

Starvation reduces the heat shock protein responses in white sturgeon larvae

This study investigates the responses of white sturgeon larvae (Acipenser transmontanus) to starvation and thermal stress, through the measurement of nutritional status (i.e. growth performances) and cellular biomarkers: heat shock proteins (Hsp) 70 and 90. White sturgeon larvae (25 day post hatch; initial weight 179.0 ± 5.1 mg) were fed (20% body weight per day) or starved for 24, 48 or 72 hrs. Every 24 hrs, five larvae from each of the starved or fed treatment replicates were exposed to heat shock resulting from an increase in water temperature from 19°C to 26°C, at a rate of 1°C per 15 min, and maintained at 26°C for 4 hrs. No mortality was observed in this study. Starvation significantly (p < 0.05) decreased the body weight and body contents of energy, protein, and lipid of the experimental larvae, compared to the fed larvae. Heat shock induced the expressions of Hsp70 and Hsp90 in both the fed and starved group; however, starvation reduced the induction at all sampling points. The current study demonstrates that poor larval nutritional status, assessed by the aforementioned parameters, reduced heat shock responses to thermal stress, as measured by heat shock protein levels. Furthermore, Hsp70 and 90 are more sensitive to heat shock and starvation, respectively. This may be, in part, a result of the different functioning of the heat shock proteins in cellular stress response and warrants further study.     

The effects of water temperature and ration size on growth and body composition of fry of common carp, Cyprinus carpio

Experiment was conducted with the aim of determining the effect of varying water temperature and ration size on growth and body composition of fry of the common carp, Cyprinus carpio. Common carp fry with an initial body weight (BW) of 0.86 g were fed a diet (34.9% protein, 18.3 KJ/g diet) at four ration sizes 4%, 5%, 6% and 7% of their body weight per day and reared at two water temperatures 28 and 32 °C for 60 days. Fry fed with 6% ration showed the highest mean final body weight at 28 °C. Final body weight was significantly (P<0.05) affected by ration and temperature. Cyprinus carpio fry raised at 28 °C had higher feed efficiency (FE) (44.36%) than the fry reared at 32 °C (40.98%) with 4% ration. Further, feed efficiency decreased with increase in ration levels in both temperatures. Protein efficiency ratio (PER) was higher (1.26) at 28 °C than at 32 °C (1.17). At 6% ration, common carp fry showed highest specific growth rate (SGR) (3.82%/day) at 28 °C as compared with at 32 °C (3.57%/day). A linear increase in protein and lipid contents was evident with increasing ration levels up to 6% body weight at both temperatures 28 and 32 °C. Second-order polynomial regression analysis of weight gain and SGR indicated the breakpoints at ration level 6.04% and 6.08% body weight per day at 28 and 32 °C. Hepatosomatic index (HSI) not affected by temperature and ration size while, viscerosomatic index (VSI) influenced (P<0.05) by ration size and temperature. Based on the above results, it may be concluded that 6% BW/day ration is optimal for growth of Cyprinus carpio fry at both the temperatures 28 and 32 °C.     

Dietary arginine supplementation enhances antioxidative capacity and improves meat quality of finishing pigs

The present study was conducted to test the hypothesis that dietary arginine supplementation may improve meat quality of finishing pigs. Beginning at ~60 kg body weight, pigs were fed a corn- and soybean meal-based diet supplemented with 0, 0.5 or 1% l-arginine until they reached a body weight of ~110 kg. On the last day of the experiment, pigs were food-deprived for 16 h before blood samples were obtained for analysis of amino acids, insulin, and other metabolites. Immediately thereafter, pigs were slaughtered for determination of carcass composition, muscle biochemical parameters, and meat quality. The result showed that arginine did not affect pig growth performance or carcass traits. However, 1% arginine decreased drip loss of pork muscle at 48 h postmortem, while increasing intramuscular fat content (P < 0.05). Supplementing 0.5 or 1% arginine to the diet increased arginine concentration and decreased cortisol level in serum, while enhancing antioxidative capacity and glutathione peroxidase activity in serum (P < 0.05). Additionally, 1% arginine increased antioxidative capacity in skeletal muscle (P < 0.05). Furthermore, 0.5 or 1% arginine decreased the cortisol receptor mRNA level in muscle (P < 0.05). Collectively, these results indicate that supplemental arginine improved meat quality and attenuated oxidative stress of finishing pigs.     

Effect of dietary carbohydrate on the growth performance,immune response,hepatic antioxidant abilities and heat shock protein 70 expression of Wuchang bream,Megalobrama amblycephala

To investigate the effects of different carbohydrate (CHO) levels in the diet of Wuchang bream Megalobrama amblycephala, the fish were randomly divided into six treatment groups. Five groups were fed 19, 25, 31, 38 and 47% CHO, respectively, for 8 weeks, and a control group was fed a diet with no CHO. Growth performance and feed utilization were significantly (P < 0.05) affected by the dietary carbohydrate level. Maximum weight gain and specific growth rate occurred at the 31% dietary carbohydrate level. Compared to the control, the 31% CHO group had a significantly increased serum total protein content, respiratory burst activity of leucocytes, serum complement 3 (C3) levels, serum lysozyme activity, serum alkaline phosphatase (AKP) activity and hepatic total antioxidative capacity (T‐AOC), as well as a decrease in serum glutamic‐oxaloacetic transaminase (GOT) activity. Compared to the control, the 47% CHO group had significantly increased serum GOT activity, and a tendency toward an increase in serum cortisol content and a decrease in serum lysozyme activity, hepatic superoxide dismutase (SOD) activity and T‐AOC. The relative level of hepatic heat shock protein 70 (HSP70) mRNA in fish fed the 38% CHO diet was significantly higher than those of fish fed the 19, 25 and 31% CHO diets, respectively (P < 0.05). After challenge with Aeromonas hydrophila, fish fed the 47% CHO had the significantly lowest post‐challenge survival, and fish fed the 31% CHO had the significantly highest post‐challenge survival (P < 0.05). The results of this study suggest that ingestion of excessive dietary CHO can impact the non‐specific immune responses, decrease the hepatic antioxidant abilities, and thus affect the health status of M. amblycephala.     

In vitro heat shock of human monocytes results in a proportional increase of inducible Hsp70 expression according to the basal content

Heat shock proteins play an important role as molecular chaperones of the cell. Inducible heat shock protein 70 is rapidly synthesised in response to numerous stressors and monocytes are sensitive to changes in core temperature resulting in a circadian variation of Hsp70 expression. Monocytes were isolated via density centrifugation from nine healthy male volunteers at 5 am, 1 pm and 9 pm, representing the nadir (5 am), peak (9 pm) and intermediate (1 pm) of Hsp70 expression in the 24-h cycle. Analysis of freshly isolated monocytes for Hsp70 expression confirmed Hsp70 levels at the three selected time points. Monocytes were subjected to in vitro heat shock at 40°C (±0.1) for 90 min with a 90 min 37°C (±0.1) exposure acting as a control. A significant increase in Hsp70 was observed at 5 am (p < 0.001) and 1 pm (p = 0.028) at 40°C when compared to 37°C but not at 9 pm (p = 0.19). A significant increase was also observed from the basal levels of Hsp70, measured on freshly isolated monocytes and the levels detected after heat shock at 40°C at 5 am (p < 0.001) and 1 pm (p = 0.001), which was not observed at 9 pm (p = 0.15). Furthermore, a significant correlation was observed in the heat shock response at 40°C and that obtained at 37°C (p < 0.001). In conclusion, the heat shock response in monocytes is directly proportional to the amount of Hsp70 present in the cells and the stress response may be much higher at different times of the day.     

Thermal biology of horseshoe crab embryos and larvae: A role for heat shock proteins

Eggs of the American horseshoe crab, Limulus polyphemus L., develop on sandy estuarine beaches during the spring and summer, and are potentially vulnerable to thermal stress during the 3-4 weeks of development to the first instar (trilobite) larval stage. In many marine taxa, heat shock (stress) proteins (Hsp's) help individuals acclimate to stresses by restoring the proper folding of cellular proteins whose shape has been altered by temperature shock or other forms of environmental stress. We examined the survival of embryos and first instar (trilobite) larvae following heat shock, and compared the levels of Hsp70 in heat shocked and control animals. Animals acclimated to 13 or 22 °C had close to 100% survival when heat shocked for 3 h at 35 or 40 °C, but exposure to 45 °C for 3 h was lethal. To study the effect of heat shock on Hsp70 production under environmentally realistic conditions, animals were acclimated to either 13 or 22 °C, heat-shocked at 35 °C for 3 h, and soluble proteins were extracted following 0, 2, 4, or 6 h recovery at 22 °C. The relative amounts of Hsp70 in horseshoe crab embryos and larvae were examined using SDS-PAGE and Western blotting. Relative to controls animals held at a constant temperature, there was a slight elevation of Hsp70 only among heat shocked trilobite larvae in the 6 h recovery treatment. Hsp70 levels did not differ significantly between control and heat shocked embryos. Horseshoe crabs have adapted to living in a thermally stressful environment by maintaining a high baseline (constitutive) level of cellular stress proteins such as Hsp70, rather than by synthesizing inducible Hsp's when stressful temperatures are encountered. This may be an effective strategy given that the heat shocks encountered by intertidal embryos and larvae occur regularly as a function of diurnal and tidal temperature changes.     

Effects of Pro-Tex® on the expression of Hsp70 gene and immune response parameters in the Persian sturgeon fingerlings,Acipenser persicus,infected with Aeromonas hydrophila

The induction of Hsps (heat shock protein) recognized as a promising approach to limiting disease and improving health in aquaculture. This investigation aimed to study the impacts of Pro-Tex®, an extract from the prickly pear cactus (Opuntia ficus indica), on the expression of Hsp70 gene and induction of immune response parameters in Acipenser persicus infected with Aeromonas hydrophila ATCC^®7966^TM. Fish were pretreated with 25, 50 and 100 mg/L of Pro-Tex and then injected in the intra-peritoneal cavity with A. hydrophila. The expression level of Hsp70 gene, lysozyme activity (LYZ) and complement C3 (C3), and immunoglobulin M (IgM) levels were assessed in liver, gill, and intestine on the days 3 and 7 post-infection. Tex-OE® increased expression of Hsp70 in a dose-dependent way in A. persicus, but this expression significantly reduced on the 7-days post-injection. The Hsp70 expression pattern was variable in each tissue, also, LYZ activity, C3, and IgM increased, depending on the concentration, and showed a decreasing trend in a time-dependent way. In conclusion, our data indicated that Pro-Tex as an Hsp70 inducer increases the resistance of sturgeon fry against fish pathogens by induction of different immunity factors.     

Variation in basal heat shock protein 70 is correlated to core temperature in human subjects

Heat shock proteins are highly conserved proteins and play an important chaperone role in aiding the folding of nascent proteins within cells. The heat shock protein response to various stressors, both in vitro and in vivo, is well characterised. However, basal levels of heat shock protein 70 (Hsp70) have not previously been investigated. Monocyte-expressed Hsp70 was determined every 4 h, over a 24 h time period, in 17 healthy male subjects (177 ± 6.4 cm, 75.7 ± 10.9 kg, 19.8 ± 4.3 years) within a temperature and activity controlled environment. Core temperature was measured at 5-min intervals during the 24 h period. Hsp70 showed significant diurnal variation (F = 7.4; p < 0.001), demonstrating peaks at 0900 and 2100 hours, and a nadir at 05.00. Core temperature followed a similar temporal trend (range = 35.96–38.10°C) and was significantly correlated with Hsp70 expression (r _s = 0.44; p < 0.001). These findings suggest a high responsiveness of Hsp70 expression in monocytes to slight variations in core temperature.     

Effect of water temperature on dietary protein requirement,growth and body composition of Asian catfish, Clarias batrachus fry

This study aimed to evaluate the protein requirement of Clarias batrachus fry, were estimated at two different water temperatures, 28 and 32 °C. The influence of dietary protein level and water temperature on body composition, weight gain, food and nutrient utilization were estimated. The Asian catfish, C. batrachus fry were fed four diets containing 28% (diet 1), 32% (diet 2), 36% (diet 3) and 40% (diet 4) protein levels and reared at two water temperatures 28 and 32 °C for 60 days. Fry fed with diet 3 containing 36% protein showed the highest mean final body weight at 32 °C. Final body weight was significantly (P<0.05) affected by dietary treatments and temperatures. Clarias batrachus fry raised at 28 °C had higher feed efficiency (93.20%) than the fry reared at 32 °C (87.58%) with 28% dietary protein level. Further, feed efficiency decreased with increase in dietary protein level. Higher daily protein retention (0.089%) observed at lower (0.0217 g) daily protein intake at 28 °C than 0.0283 g at 32 °C. While, optimal (0.0282 g) daily protein intake showed higher daily weight gain at 32 °C. Productive protein value (% PPV) was maximum (1.76%) at 32 °C than at 28 °C (0.76%). Final body lipid recorded higher value than initial body lipid at both the temperatures. Hepatosomatic index (HSI) observed to have been influenced (P<0.05) by diets and temperatures, while viscerosomatic index (VSI) affected (P<0.05) by only diets and not (P>0.05) by temperatures. The study concluded that the diet 3 containing 36% protein was optimal for growth of C. batrachus fry at both the temperatures.     

Effects of anthraquinone extract from Rheum officinale Bail on the physiological responses and HSP70 gene expression of Megalobrama amblycephala under Aeromonas hydrophila infection

We evaluated the effect of dietary supplementation with anthraquinone extract (from Rheum officinale Bail) on the resistance to Aeromonas hydrophila infection in Megalobrama amblycephala. The fish were randomly divided into two groups: a control group (fed a standard diet) and a treatment group (standard diet supplemented with 0.1% anthraquinone extract) and fed for 10 weeks. We then challenged the fish with A. hydrophila and recorded mortality and changes in serum cortisol, lysozyme, alkaline phosphatase (ALP), total protein, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and hepatic catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA) and the relative expression of heat shock protein 70 (HSP70) mRNA for a period of 5 d. Supplementation with 0.1% anthraquinone extract significantly increased serum lysozyme activity before infection, serum ALP activity at 24 h after infection, serum total protein concentration 12 h after infection, hepatic CAT activity 12 h after infection, hepatic SOD activity before infection, and the relative expression of hepatic HSP70 mRNA both before infection and 6 h after infection. In addition, the supplemented group had decreased levels of serum cortisol 6 h after infection, serum AST and ALT activities 12 h after infection, and hepatic MDA content 12 h after infection. Mortality was significantly lower in the treatment group (86.67%) than the control (100%). Our results suggest that ingestion of a basal diet supplemented with 0.1% anthraquinone extract from R. officinale Bail can enhance resistance against pathogenic infections in M. amblycephala.     

Dietary supplementation of fructooligosaccharide (FOS) improves the innate immune response, stress resistance, digestive enzyme activities and growth performance of Caspian roach (Rutilus rutilus) fry

The present study investigated the effects of prebiotic fructooligosaccharide (FOS) on the innate immune response, stress resistance, digestive enzyme activities, growth factors and survival of Caspian Roach (Rutilus rutilus) fry. After acclimation, fish (0.67 ± 0.03 g) were allocated into 12 tanks (50 fish per tank) and triplicate groups were fed a control diet or diets containing 1%, 2% or 3% FOS. At the end of the trial (7 weeks), humoral innate immune parameters (serum Ig levels, lysozyme activity and alternative complement activity (ACH50)), resistance to salinity stress (150 g L⁻¹), digestive enzyme activities (amylase, lipase and protease) and growth factors (final weight, weight gain, specific growth rate (SGR), food conversion ratio (FCR), and condition factor) were assessed. At the end of the study the innate immune responses (Ig levels, lysozyme activity and ACH50) were significantly higher in 2% and 3% FOS fed fish (P < 0.05), whereas, 1% dietary FOS only elevated serum lysozyme activity. All dietary FOS levels significantly increased resistance to a salinity stress challenge (P < 0.05) and highest survival was observed in the 3% FOS group. Similarly, digestive enzyme activities were significantly elevated with increasing levels of dietary FOS (P < 0.05). Subsequently, elevated growth performance (final weight, SGR and FCR) was observed in roach fed 2% and 3% FOS compared to the control group (P < 0.05). These results indicate that FOS can be considered as a beneficial dietary supplement for improving the immune response, stress resistance, digestive enzyme activities and growth performance of Caspian roach fry.     

Optimization of the culture methods for nursing Chinese black sleeper (Bostrychus sinensis Lacépède, 1801) fry using an orthogonal array design

Chinese black sleeper (Bostrychus sinensis) is a burrow‐dwelling fish found in intertidal mudflats. As a commercially important fish in southern China, the nursing of B. sinensis fry is a critical step for its farming. The growth and survival of B. sinensis fry are closely related to the stocking density, shelter and diet. In this study, 1575 healthy fry were used to investigate the effects of three factors, namely: diet, stocking density, and shelter on the survival rate (SR), specific growth rate (SGR) and condition factor (CF). The optimal combinations of three levels of each of these three factors (A1‐3, B1‐3 and C1‐3) were also determined, using an orthogonal array design of OA₉ (3⁴). After 50 days of nursing, the results showed that: (i) the best combinations for the three factors at their optimal levels were A1B1C2 or A1B1C3; (ii) factor A was the most important factor and had significant effects (P < 0.05) on the SR and SGR of the fry, while the other factors had no significant effects (P > 0.05); (iii) the SGR, SR and CF of fry fed with commercial formulated feed (CFF) were significantly higher (P < 0.05) compared to those of fry fed with minced trash fish (MTF); and (iv) the fry fed with MTF mixed with antimicrobial peptides (MTF+AMP) showed higher SGR, SR and CF than those fed with MTF alone, which indicated that the antimicrobial peptides had positive effects on the growth and survival of the fry.     

Mild heat stress at a young age in<Emphasis Type="Italic">Drosophila melanogaster</Emphasis> leads to increased Hsp70 synthesis after stress exposure later in life

In a number of animal species it has been shown that exposure to low levels of stress at a young age has a positive effect on stress resistance later in life, and on longevity. The positive effects have been attributed to the activation of defence/cleaning systems (heat shock proteins (Hsps), antioxidases, DNA repair) or to effects of a changed metabolic rate, or both. We investigated the effect of mild stress exposures early in life on Hsp70 synthesis after a harder stress exposure later in life in five isofemale lines ofDrosophila melanogaster. Female flies were either exposed to repeated bouts of mild heat stress (3 h at 34‡C) at a young age (days 2, 4 and 6 post-eclosion) or held under standard laboratory conditions. At 16 and 32 days of adult age, respectively, flies were exposed to a high temperature treatment known to induce Hsp70 in the investigated species (1 h at 37‡C). Thereafter, the inducible Hsp70 levels were measured. Our data show a tendency towards increased Hsp70 synthesis with increased age for both ’mild stress’ and ’no stress’ flies. Moreover, the results show that flies exposed to mild stress at a young age synthesized more Hsp70 upon induction, compared to control flies, and that this difference was accentuated at 32 days compared to 16 days of age. Thus, bouts of mild heat stress at a young age impact on the physiological stress response system later in life. This may be caused by an increased ability to react to future stresses. Alternatively, the mild stress exposure at a young age may actually have caused cellular damages increasing the need for Hsp70 levels after stress exposure later in life. The importance of an Hsp70 upregulation (throughout life) in explaining the phenomenon of hormesis is discussed, together with alternative hypotheses, and suggestions for further studies.     

Differential stress responses among newly received calves: variations in reductant capacity and Hsp gene expression

Bovine respiratory disease complex (BRD), a major economic concern to the beef cattle industry all over the world, is triggered by physical, biological and psychological stresses. It is becoming noticeable that the key to reducing BRD appears to be centered at reducing the response to stress. The aims of the present study were to detect individual variations in the stress response of newly received young calves through their leukocyte heat shock protein (Hsp) response, selected neutrophil-related gene expression and oxidative stress, and relate them to pulmonary adhesions at slaughter, an indicative sign of clinical and subclinical episodes of BRD at an early age. Differential expression patterns of Hsp60 and Hsp70A1A were revealed in newly received calves 1 h, 5 h and 1 day after arrival, distinguishing between stress-responsive and non-stress-responsive individuals. Plasma cortisol was also indicative of stress-responsive and non-stress-responsive individuals, 1 h and 5 h after arrival. At the longer term, β-glycan levels were highest 7 days after arrival and significantly correlated with an adhesion-free phenotype at slaughter. Oxidative stress responses, measured through the oxidation products of the exogenous linoleoyl tyrosine (LT) marker, revealed that hydroperoxidation and epoxidation of membranes may readily occur. Based on the LT oxidation products and levels of β-glycan, we present a discriminant analysis model, according to which vulnerable individuals may be predicted at near 100% probability 7 days after arrival. Since clinical signs of BRD may often go undetected in feedlot calves, such a model, after its examination in large-scale experiments, may be a reliable tool for an early prediction of subclinical signs of BRD.     

Theiler’s murine encephalomyelitis virus infection induces a redistribution of heat shock proteins 70 and 90 in BHK-21 cells,and is inhibited by novobiocin and geldanamycin

Theiler’s murine encephalomyelitis virus (TMEV) is a positive-sense RNA virus belonging to the Cardiovirus genus in the family Picornaviridae. In addition to other host cellular factors and pathways, picornaviruses utilise heat shock proteins (Hsps) to facilitate their propagation in cells. This study investigated the localisation of Hsps 70 and 90 in TMEV-infected BHK-21 cells by indirect immunofluorescence and confocal microscopy. The effect of Hsp90 inhibitors novobiocin (Nov) and geldanamycin (GA) on the development of cytopathic effect (CPE) induced by infection was also examined. Hsp90 staining was uniformly distributed in the cytoplasm of uninfected cells but was found concentrated in the perinuclear region during late infection where it overlapped with the signal for non-structural protein 2C within the viral replication complex. Hsp70 redistributed into the vicinity of the viral replication complex during late infection, but its distribution did not overlap with that of 2C. Inhibition of Hsp90 by GA and Nov had a negative effect on virus growth over a 48-h period as indicated by no observable CPE in treated compared to untreated cells. 2C was detected by Western analysis of GA-treated infected cell lysates at doses between 0.01 and 0.125 μM, suggesting that processing of viral precursors was not affected in the presence of this drug. In contrast, 2C was absent in cell lysates of Nov-treated cells at doses above 10 μM, although CPE was evident 48 hpi. This is the first study describing the dynamic behaviour of Hsps 70 and 90 in TMEV-infected cells and to identify Hsp90 as an important host factor in the life cycle of this virus.     

Modifying the physiological responses to handling stress in beluga sturgeon Huso huso (Linnaeus, 1758); Interactive effects of feeding time and dietary fat

The present study investigated the interaction of feeding times with two dietary fat levels on physiological responses to handling stress in juvenile Beluga sturgeon. Fish were fed with two different diets (high energy; HE: 24% fat and low energy; LE: 12% fat) for 8 weeks at two feeding times; 09:00 and 16:00 (during the day) or 21:00 and 04:00 (during the night). At the end of the trial, blood samples were taken and the resting fish were held in a net out of water for 90 s as the handling stressor. Three hours after application of stress, post‐stress blood was taken. Cortisol, glucose, and lactate concentrations were considered as stress indicators. The mean values of cortisol and lactate levels did not reveal a significant difference between pre‐ and 3‐hr post‐stress samples, but the average concentration of glucose showed a significant difference. Cortisol, lactate and glucose concentrations were not influenced by the difference in the diets. Moreover, the cortisol and lactate concentrations were not affected by the different feeding times, while glucose levels were significantly affected by the feeding times with the lowest level in fish fed during the day. With respect to stress indicators, the results revealed that feeding times affected pre‐ and post‐stress secondary response to handling stress, but the rate and magnitude of metabolites (cortisol, glucose and lactate) were not affected by dietary fat levels. Therefore, it is necessary to examine the best feeding times with the interaction of feed ingredients in sturgeon farming.     

Larval rearing of fringe-lipped carp,Labeo fimbriatus (Bloch) with low cost diets including green bottle fly Lucilia sericata (Meigen) larvae meal incorporated diet

A study was conducted with non-conventional ingredients to test their efficacy as fishmeal (FM) replacers in the diet of fringe- lipped carp. Labeo fimbriatus first feeding larvae and fry were reared for 30 and 60 days in indoor, 50 L, aerated, circular plastic tanks at 100 and 30 numbers tank⁻¹, respectively. In the first feeding larvae to fry rearing experiment (Exp. 1), the fish were fed with either of the following isonitrogenous and isocaloric diets – live plankton, FM diet, green bottle fly (Lucilia sericata) larvae meal (GBFLM) diet and silkworm pupa (SWP) diet. The fry to fingerling rearing (Exp. 2), was also conducted using the same diets described above except live plankton. All compounded diets were formulated to contain 40% crude protein for the experiment 1 and 35% for experiment 2 and were fed ad libitum. Triplicate tanks were maintained for each treatment in both the experiments. In Exp. 1, the mean final weight of fry was higher with plankton and FM diets, while no difference (p > .05) was observed between FM and GBFLM diets. Weight of fish fed SWP diets was not statistically different from those fed GBFLM diet. No difference (p > .05) in final length, survival and condition factor was recorded. Analysis of digestive enzyme activity of whole fish revealed lower (p < .05) activity of amylase in fish fed plankton. In Exp. 2, no difference (p > .05) was observed between the different diet groups in terms of mean final weight, length, survival and condition factor. Analysis of digestive enzyme activity of whole fish revealed no difference (p > .05) in the activity of digestive enzymes between the treatments except a lower (p < .05) activity of trypsin in FM diet and lipase in FM and GBFLM diets. Since the survival and condition factors of animals is the most important aspect during nursery rearing, similar (p > .05) values recorded in different treatments indicate the possibility of incorporation of these non-conventional protein sources in the diet of L. fimbriatus during first feeding larvae to fry and fry to fingerling rearing.