Dry Body Weight Research Articles

Numerical expression of volume status using the bioimpedance ratio in continuous ambulatory peritoneal dialysis patients: A pilot study.

BackgroundVolume overload results in higher mortality rates in patients on continuous ambulatory peritoneal dialysis (CAPD). The ratio of bioimpedance (RBI) might be a helpful parameter in adjusting dry body weight in CAPD patients. This study examined whether it is possible to distinguish between non-hypervolemic status and hypervolemic status in CAPD patients by using only RBI.MethodsRBI was calculated as follows: RBI = impedance at 50 kHz/impedance at 500 kHz. Based on the experts’ judgements, a total of 64 CAPD patients were divided into two groups, a non-hypervolemic group and a hypervolemic group. The RBI was measured from right wrist to right ankle (rw-raRBI) by bioimpedance spectroscopy (BCM®, Fresenius Medical Care) before and after the peritosol was emptied. Other RBIs were measured from the right side of the anterior superior iliac spine to the ipsilateral ankle (rasis-raRBI) to control for the electro-physiological effects of peritoneal dialysate.ResultsThe mean rw-raRBI of non-hypervolemic patients was higher than that of hypervolemic patients in the presence (1.141 ± 0.022 vs. 1.121 ± 0.021, P < 0.001) of a peritosol. Likewise, the mean rasis-raRBI of non-hypervolemic patients was higher than that of hypervolemic patients (presence of peritosol: 1.136 ± 0.026 vs. 1.109 ± 0.022, P < 0.001; absence of peritosol: 1.131 ± 0.022 vs. 1.107 ± 0.022, P < 0.001).ConclusionThe volume status of CAPD patients was able to be simply expressed by RBI. Therefore, this study suggests that when patients cannot be analyzed using BCM, RBI could be an alternative.

Neglect of lactation stage leads to naive assessment of residual feed intake in dairy cattle

Residual feed intake (RFI) is a candidate trait for feed efficiency in dairy cattle. We investigated the influence of lactation stage on the effect of energy sinks in defining RFI and the genetic parameters for RFI across lactation stages for primiparous dairy cattle. Our analysis included 747 primiparous Holstein cows, each with recordings on dry matter intake (DMI), milk yield, milk composition, and body weight (BW) over 44 lactation weeks. For each individual cow, energy-corrected milk (ECM), metabolic BW (MBW), and change in BW (ΔBW) were calculated in each week of lactation and were taken as energy sinks when defining RFI. Two RFI models were considered in the analyses; RFI model [1] was a 1-step RFI model with constant partial regression coefficients of DMI on energy sinks (ECM, MBW, and ΔBW) over lactation. In RFI model [2], data from 44 lactation weeks were divided into 11 consecutive lactation periods of 4 wk in length. The RFI model [2] was identical to model [1] except that period-specific partial regressions of DMI on ECM, MBW, and ΔBW in each lactation period were allowed across lactation. We estimated genetic parameters for RFI across lactation by both models using a random regression method. Using RFI model [2], we estimated the period-specific effects of ECM, MBW, and ΔBW on DMI in all lactation periods. Based on results from RFI model [2], the partial regression coefficients of DMI on ECM, MBW, and ΔBW differed across lactation in RFI. Constant partial regression coefficients of DMI on energy sinks over lactation was not always sufficient to account for the effects across lactation and tended to give roughly average information from all period-specific effects. Heritability for RFI over 44 lactation weeks ranged from 0.10 to 0.29 in model [1] and from 0.10 to 0.23 in model [2]. Genetic variance and heritability estimates for RFI from model [2] tended to be slightly lower and more stable across lactation than those from model [1]. In both models, RFI was genetically different over lactation, especially between early and later lactation stages. Genetic correlation estimates for RFI between early and later lactation tended to be higher when using model [2] compared with model [1]. In conclusion, partial regression coefficients of DMI on energy sinks differed across lactation when modeling RFI. Neglect of lactation stage when defining RFI could affect the assessment of RFI and the estimation of genetic parameters for RFI across lactation.

Effect of stocking rate and animal genotype on dry matter intake, milk production, body weight, and body condition score in spring-calving, grass-fed dairy cows.

The objective of the experiment was to quantify the effect of stocking rate (SR) and animal genotype on milk production, dry matter intake (DMI), energy balance, and production efficiency across 2 consecutive grazing seasons (2014 and 2015). A total of 753 records from 177 dairy cows were available for analysis: 68 Holstein-Friesian and 71 Jersey × Holstein-Friesian (JxHF) cows each year of the experiment under a pasture-based seasonal production system. Animals within each breed group were randomly allocated to 1 of 3 whole-farm SR treatments defined in terms of body weight per hectare (kg of body weight/ha): low (1,200 kg of body weight/ha), medium (1,400 kg of body weight/ha), and high (1,600 kg of body weight/ha), and animals remained in the same SR treatments for the duration of the experiment. Individual animal DMI was estimated 3 times per year at grass using the n-alkane technique: March (spring), June (summer), and September (autumn), corresponding to 45, 111, and 209 d in milk, respectively. The effects of SR, animal genotype, season, and their interactions were analyzed using mixed models. Milk production, body weight, and production efficiency per cow decreased significantly as SR increased due to reduced herbage availability per cow and increased grazing severity. As a percentage of body weight, JxHF cows had higher feed conversion efficiency, higher DMI and milk solids (i.e., kg of fat + kg of protein) production, and also required less energy intake to produce 1 kg of milk solids. The increased production efficiency of JxHF cows at a similar body weight per hectare in the current analysis suggests that factors other than individual cow body weight contribute to the improved efficiency within intensive grazing systems. The results highlight the superior productive efficiency of high genetic potential crossbred dairy cows within intensive pasture-based milk production systems at higher SR where feed availability is restricted.

Effect of increasing monensin sodium levels in diets with virginiamycin on the finishing of Nellore cattle.

This study evaluated the effect of increasing levels of monensin sodium (MON) in diets with virginiamycin (VM) on the finishing of feedlot cattle. Two hundred and eighty intact male Nellore cattle (348±32kg body weight, 22months) received one of the following five diets: control diet (without additives); diet containing VM (25mg per kg dry matter) combined with 0 (MON0), 10 (MON10), 20 (MON20) or 30 (MON30) mg MON per kg dry matter. During adaptation (28days), the MON0 diet increased dietary net energy for maintenance and gain compared to the control diet (P=0.04). The combination of additives linearly reduced dry matter intake, body weight and average daily gain (P<0.01). Considering the total study period (110days), there was a trend of greater net energy intake for maintenance (P=0.09) and hot carcass weight (P=0.06) for animals fed MON0 compared to the control diet. The combination of additives linearly reduced dry matter intake (P=0.04) and linearly increased gain:feed and dietary net energy for maintenance and gain (P<0.01). The combination of VM with MON at a dose of 30mg/kg dry matter is recommended for Nellore feedlot cattle because it improves the efficiency of energy utilization.

Effects of phosalone consumption via feeding with or without sodium bentonite on performance, blood metabolites and its transition to milk of Iranian Baluchi sheep

BackgroundTransfer of pesticides from environment to animal products is inevitable, so the purpose of the present work was to evaluate phosalone consumption via feeding with or without sodium bentonite (SB) on performance, blood metabolites and its transition to milk of Iranian Baluchi sheep.MethodsTwenty Baluchi ewes were divided into four treatments (P1 as control, P2, P3, and P4) of five animals in which phosalone, an organophosphate pesticide, was given via diet (only for P2 and P3) at a dose of 280 mg/sheep/day for 63 consecutive days. The SB (32 g/sheep/day; for P3 and P4) was also evaluated for its ability to reduce deleterious effects of phosalone in the sheep diets. The control group (P1) did not receive any phosalone and SB during the experiment. Sampling was conducted in two periods of time including weeks 5 and 9.ResultsPhosalone residues were observed in the milk samples of P2 and P3 groups during two sampling periods. During period 1, the transfer rate of phosalone from feed to milk was 0.23 and 0.02%, respectively for the contaminated diets (P2 and P3), which is relatively similar to period 2 (0.22 and 0.02%). Only 0.34 (period 1) and 0.36% (period 2) of phosalone residue are excreted in the feces of P2 group following its daily consumption. Transfer of phosalone from feed to milk was affected (P < 0.05) by the dietary inclusion of a commercial SB, as it (SB) decreased excretion of phosalone via milk (P3). The phosalone and SB alone or together had no significant effect (P > 0.05) on the dry matter intake (DMI) and body weight (BW) gain, but feed efficiency, milk production, milk fat, dry matter (DM) and organic matter (OM) digestibility, acetylcholinesterase (AChE) inhibitory activity, hemoglobin (Hb), red blood cell (RBC), serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT), albumin and mean corpuscular hemoglobin concentration (MCHC) affected by the treatments in period 1 or 2 (P < 0.05). The Hb, RBC, and MCHC were significantly decreased (P < 0.05) by about 9.72, 20.77, and 9.71%, respectively in the group P2 as compared to those of the control group during period 1. The AChE inhibitory activity (period 1 and 2) significantly increased when phosalone administered via the diet (P < 0.05).ConclusionsAlthough there were no adverse effects on the performance of sheep following the intake of phosalone alone (P2 vs. P1), but other research on the long and short times to the phosalone in high and low doses with more animals is suggested. Overall, compared to the control group, addition of SB in the diet of sheep improved nutrient digestibility, animal performance, and milk health.

Reproductive output of two benthic resources (Fissurella latimarginata and Loxechinus albus) under different management regimes along the coast of central Chile

Normal 0 21 false false false ES-CL JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri; mso-ansi-language:ES-CL; mso-fareast-language:ES-CL;} The biological and ecological benefits of fully and partially marine protected areas are well documented. However, the benefits reaching areas beyond the limits of the reserves are still emerging in spite the fact that they are essential for fishing grounds recovery and to gain support for the protection of the ocean among stakeholders. We analyzed the influence of protection on gonadosomatic index, and also body dry weight, of two economically and ecologically important species: the keyhole limpet, Fissurella latimarginata and the red sea urchin, Loxechinus albus , in order to determine the value of protected areas in directly enhancing reproduction, and therefore potential seeding on exploited areas. We compared two levels of protection in central Chile, determined by fisheries management regimes (in turn associated to fishing pressure): a) areas with fishing restrictions (low or none fishing effort; territorial use rights for fisheries and no-take areas) and b) open access areas (high exploitation rates). We also evaluated the independent influence of upwelling on both variables. Our results show for both species that a) body dry weight is not affected by management regime, b) management regime did not show a consistent impact on gonadosomatic index and c) upwelling did not affect the response variables. Our findings help disentangling the main factors determining reproductive patterns under contrasting human impact scenarios, suggesting that the selection of sites for establishing marine protected areas seems to be less relevant than efficient control of fishing effort and minimum legal size to assure natural seeding.

Condition Index of Meretrix lyrata (Sowerby 1851) and its Relationship with Water Parameter in Sarawak

Condition Index (CI) was used to estimate the reproductive biology cycle of the hard clam Meretrix lyrata based on dry body weight and shell weight. High CI value was observed due to the increase in the body weight of the hard clam that corresponding to the maturity stage and early spawning. The CI value of M. lyrata from Buntal Village, Kuching, Sarawak showed three highest peaks during the 12-month study on May and October 2013 and March 2014. The lowest CI values were obtained in September and November 2013 and April 2014. Ammonia nitrogen was the only water parameter that significantly correlated to the CI values. The CI application is important to estimate the maturity of hard clam gonad to facilitate conservation activity through the hard clam harvesting out of the gonad maturation and spawning period.

Estimation of maintenance energy requirements in German shepherd and Labrador retriever dogs in Bangalore, India

Maintenance energy requirements (MERs) were calculated for 17 German shepherd and 20 Labrador retriever adult dogs using an in-home prospective dietary trial. The dogs were fed the same dry pet food and body weight, food intake, body condition score and physical activity were monitored for 10weeks. Labrador retrievers were significantly heavier and had higher body condition scores than German shepherd dogs, but there was no difference between males and females within each group. Body weights remained stable over the study period, with an average daily gain of 9.1g. Mean (SD) MER was 103.4 (16.3) kcal/kg BW0.75 , which was some 20% lower than that currently suggested for moderately active young adult dogs. Individual MER ranged from 66.8 to 141kcal/kg BW0.75 . There were no significant differences in MER between the two breeds, or between males and females within and between the two breeds. There was a significant inverse relationship between MER and body condition score, reflecting the lower energy expenditure of adipose tissue. The lower MER of dogs in this study, relative to previous observations, may reflect climatic and environmental differences and highlight the necessity for accurate estimates of MER in relation to the production and feeding of pet foods.

Population differences in host plant preference and the importance of yeast and plant substrate to volatile composition.

Divergent selection between environments can result in changes to the behavior of an organism. In many insects, volatile compounds are a primary means by which host plants are recognized and shifts in plant availability can result in changes to host preference. Both the plant substrate and microorganisms can influence this behavior, and host plant choice can have an impact on the performance of the organism. In Drosophila mojavensis, four geographically isolated populations each use different cacti as feeding and oviposition substrates and identify those cacti by the composition of the volatile odorants emitted. Behavioral tests revealed D. mojavensis populations vary in their degree of preference for their natural host plant. Females from the Mojave population show a marked preference for their host plant, barrel cactus, relative to other cactus choices. When flies were given a choice between cacti that were not their host plant, the preference for barrel and organ pipe cactus relative to agria and prickly pear cactus was overall lower for all populations. Volatile headspace composition is influenced by the cactus substrate, microbial community, and substrate‐by‐microorganism interactions. Differences in viability, developmental time, thorax length, and dry body weight exist among populations and depend on cactus substrate and population‐by‐cactus interactions. However, no clear association between behavioral preference and performance was observed. This study highlights a complex interplay between the insect, host plant, and microbial community and the factors mediating insect host plant preference behavior.

Effect of Prill Fat and Rumen Protected Choline Supplementation on Feed Intake, Body Weight Changes and Economics of Lactating Murrah Buffaloes

The present study was carried out to evaluate the effect of prill fat and rumen protected choline supplementation on daily dry matter intake, body weight changes and economics in lactating Murrah buffaloes (n=18) divided into three equal groups (Control, T1 and T2). Buffaloes in all the three groups were fed similar basal diet as total mixed ration comprising of berseem green fodder, wheat straw and concentrate mixture. Buffaloes in T1 group were daily supplemented with prill fat @ 2.5% of total DMI whereas; buffaloes in T2 group were daily supplemented with 54 g rumen protected choline along with same quantity of prill fat as supplemented in T1 group. Fortnightly and overall dry matter intake and body weight of experimental buffaloes was comparable in all the three groups. Net profit/animal/day () was increased by 3.12 and 8.25% in T1 and T2 groups over the control. Thus it was concluded that supplementing prill fat in the ration of lactating Murrah buffaloes increased the net profit without any significant effect on dry matter intake and body weight changes, which was furthermore enhanced by supplementing the ration with rumen protected choline.

Leaf-litter preferences of the introduced freshwater shrimps Atyaephyra desmarestii and Neocaridina davidi

Detailed knowledge of the significance of shrimps in freshwater food webs is very limited. However, determination of the current potential invasion of shrimps into European freshwater systems requires information on their ecology and feeding behaviour. Atyaephyra desmarestii has established stable populations in Western and Central Europe, while the ornamental species Neocaridina davidi was released in 2009 into a small tributary of the Erft River (North Rhine Westphalia, Germany), where it has thrived. Both species use leaf-litter as a significant food source. In this study, we assessed a reproducible method to compare the preferences of this two shrimp species for decaying leaves of four different species of deciduous tree: alder (Alnus glutinosa), Italian poplar (Populus x canadensis), pedunculate oak (Quercus robur) and goat willow (Salix caprea). We also determined the relevance of A. desmarestii and N. davidi in leaf-litter breakdown. Adults of both species showed a significant preference for leaves of alder and Italian poplar, whereas juvenile individuals did not favour any particular leaf species. A. desmarestii and N. davidi adults exhibited higher night-time than daytime activity. Diurnal consumption rates were determined for N. davidi. It consumed 51.0% leaf litter dry weight per body dry weight per day. Alnus and Salix leaves (including biofilm) made up the majority of the diet of Neocaridina, followed by Populus and Quercus leaves. Our results demonstrate the distinct relevance of leaf-litter in the diet of freshwater shrimps, and their role in leaf-litter breakdown. While the invasion potential of A. desmarestii seems to be relatively low, at least for now, N. davidi has thus far been a very successful invader. This is supported by its high feeding rates on leaf litter of the regional vegetation. Since there is no indigenous shrimp species in the study area, the potential implications of the invasion process merit further investigation.

Feeding Effect of Shatavari (Asparagus recemosus) Supplementation on Dry Matter Intake, Body Weight and Milk Yield in Lactating Cows

Feeding Effect of Shatavari (<i>Asparagus recemosus</i>) Supplementation on Dry Matter Intake, Body Weight and Milk Yield in Lactating Cows

Improving Live and Dry Body Weight Gain of Bovine Native Calves during Hot Summer Season of Egypt using Genetic Crossing Process

Improving Live and Dry Body Weight Gain of Bovine Native Calves during Hot Summer Season of Egypt using Genetic Crossing Process

Experimental study of Bisacodyl in the treatment of slow transit constipation model rats

To explore the efficacy and the mechanism of Bisacodyl in treating slow transit constipation model rats. A total of 30 healthy rats were enrolled. Twenty rats received intragastric diphenoxylate to develop slow transit constipation (STC) model, and 10 untreated rats were set as blank control. STC rats were subdivided into two groups: STC Bisacodyl group (fed with Bisacodyl) and STC control group (common feed). Body weight, number and dry weight of faeces, and intestinal transit time were compared among 3 groups. Interstitial cells of Cajal(ICC) and c-Kit protein expression were measured by immunohistochemical staining. Restults Compared to blank control rats, at 100-day of receiving intragastric diphenoxylate, above 20 rats presented the decrease of body weight and feces number, the increase of dry weight of faeces, and the delay of intestinal transit time, indicating the successful establishment of STC rat model. One month after feeding, compared to STC control group, STC Bisacodyl grap had an increased feces number[(36.6±6.8) pill/day vs. (26.8±6.0) pill/day], decreased dry weight of feces [(150.6±10.5) mg/pill vs. (171.6±16.3) mg/pill] and shortened intestinal transit time [(416.9±50.6) minutes vs. (495.3±66.8) minutes], and the differences were statistically significant(all P<0.05). Dissolution of ICC basement membrane, damage of connection between ICC and surrounding cells, and atrophy of ICC nucleus structure were found in STC control rats. ICC (8.20±1.92 per field] and c-Kit expression (12.68%±2.59% ) in STC control rats were significantly lower than those in blank control rats(36.00±6.25 per field and 71.50 %±8.27%) (P=0.000). Compared to STC control group, the connection between ICC and surrounding cells enhanced obviously, ICC (18.80±3.70 per field) and c-Kit expression (45.91%±6.80%) were significantly higher in STC Bisacodyl group (all P=0.000). Bisacodyl treatment can relieve STC symptoms, which may be associated with increased ICC number and c-Kit protein expression.

Does long-term fungicide exposure affect the reproductive performance of leaf-shredders? A partial life-cycle study using Hyalella azteca

Leaf-shredding amphipods play a critical role in the ecosystem function of leaf litter breakdown, a key process in many low order streams. Fungicides, however, may adversely influence shredders' behavior and the functions they provide, while there is only limited knowledge concerning effects on their reproductive performance. To assess the latter, a semi-static 56-day partial life-cycle bioassay using the model shredder Hyalella azteca (n = 30) was performed applying two environmentally relevant concentrations of a model fungicide mixture (i.e., 5 and 25 μg/L) composed of five fungicides with different modes of toxic action. Variables related to the food processing (leaf consumption and feces production), growth (body length and dry weight), energy reserves (lipid content), and reproduction (amplexus pairs, number and length of offspring) were determined to understand potential implications in the organisms' energy budget. While the fungicides did not affect leaf consumption, both fungicide treatments significantly reduced amphipods' feces production (∼20%) compared to the control. This observation suggests an increased food utilization to counteract the elevated and stress-related energy demand: although growth as well as energy reserves were unaffected, amplexus pairs were less frequently observed in both fungicide treatments (∼50–100%) suggesting a tradeoff regarding energy allocation favoring the maintenance of fundamental functions at the organism level over reproduction. As a result, the time to release of first offspring was delayed in both fungicide treatments (7 and 14 days) and the median number of offspring was significantly lower in the 25-μg/L treatment (100%), whereas offspring length remained unaffected. The results of this study thus indicate that chronic fungicide exposures can negatively impact shredders' reproductive performance. This may translate into lower abundances and thus a reduced contribution to leaf litter breakdown in fungicide-impacted streams with potentially far-reaching consequences for detritus-based food webs.

1411 The effect of by-product inclusion and concentrate feeding level on milk production and composition, pasture dry matter intake, body weight and body condition score of mid-late lactation spring calving grazing dairy cows

1411 The effect of by-product inclusion and concentrate feeding level on milk production and composition, pasture dry matter intake, body weight and body condition score of mid-late lactation spring calving grazing dairy cows

Bioaccumulation, Depuration, and Transfer to Offspring of 13C-Labeled Fullerenols by Daphnia magna.

Fullerenols have wide application in the field of life sciences as a result of their extensive biocompatibility and biofunctionality. However, their environmental fate and ecotoxicological risks are largely unknown. In this study, stable isotope (13C) labeling was applied to investigate the bioaccumulation and depuration of fullerenols in Daphnia magna. By incorporation of 13C on the skeleton of fullerenols, the concentrations of fullerenols in the samples could be precisely determined on the basis of carbon isotope ratios (13C/12C). After exposure to 13C-labeled fullerenols in artificial freshwater for 48 h, the steady concentrations of fullerenols in D. magna were nearly 0.39 and 1.37% of the dry body weight in the 0.1 and 1.0 mg/L exposure groups, respectively. After 48 h of depuration, D. magna could excrete 97.34 and 89.56% of the accumulated fullerenols in 0.1 and 1.0 mg/L exposure group, respectively. The depuration of fullerenols from D. magna followed first-order kinetics. Moreover, accumulated fullerenols in gravid D. magna could be transferred to the next generation of neonates. The results in present study demonstrated that stable isotope (13C) labeling is a powerful tool to investigate the environmental fate and the potential impacts of fullerenols in ecological systems.

Toxicokinetics and time-variable toxicity of cadmium in Oppia nitens Koch (Acari: Oribatida).

The soil-living mite Oppia nitens Koch has recently been proposed as a promising test species for the ecotoxicological risk assessment of contaminated boreal soils. Adding oribatid mites to the assemblage of test species for soil is highly desirable given the enormous diversity and ecological significance of these microarthropods. The authors aimed at revealing how toxicity, lethal body concentration, and bioaccumulation of cadmium (Cd) changed over a period of 7 wk when mites were exposed to Cd-spiked natural soils. The estimated median lethal concentration (LC50) values showed a gradual decrease with time, but a steady state was not reached within 7 wk. Estimates for lethal body concentration varied from 44 μg Cd/g to 91 μg Cd/g dry body weight, with a tendency to increase with time. The estimated 50% effective concentration (EC50) for effects on reproduction after 7-wk exposure was 345 μg Cd/g dry soil. Accumulation of Cd in mites was extremely variable but overall showed a nonsaturating increase. A simple 1-compartment toxicokinetic model did not describe the data well. The analysis suggests that O. nitens has a storage-detoxification strategy that is not at equilibrium under chronic exposure. Considering the tiny body size of the animal, it is remarkable that long exposure times are necessary to reveal chronic toxicity. The use of oribatids provides a clear added value to soil risk assessment but trades off with exposure length. Environ Toxicol Chem 2017;36:408-413. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Effect of temperature on the reproductive success, developmental rate and brood characteristics of Ips sexdentatus (Boern.)

Abstract Global warming is predicted to enhance the development rate and increase the number of generations in multivoltine insects. For secondary forest pests, such as the pine bark beetle Ips sexdentatus, the resulting increase in population level could trigger more frequent outbreaks. However, this positive effect could be outweighed by a temperature‐dependent decrease in offspring quality. To test these hypotheses, we carried out a laboratory rearing experiment with maritime pine logs at six temperature regimes reproducing hourly fluctuations and averaging 12–25.5 °C. We estimated the thermal requirements for a complete development of the beetle and the number of offspring per female. The offspring quality was estimated using three traits: dry body weight, elytra length and lipid content. The minimum and maximum developmental threshold were estimated at 10.9 and 36 °C, respectively, and the thermal requirements for complete development were estimated at 517 degree‐days. We predicted a mean of two generations per year in southwestern France, although an additional generation could occur during warmer years. The number of offspring increased exponentially with temperature, although we observed a curvilinear response of offspring traits to temperature, with optima at 15–18 °C. This suggests that there are trade‐offs between productivity and quality of offspring. Global warming is therefore likely to result in higher number of generations of I. sexdentatus per year, with larger broods but of reduced fitness at high temperatures.

Molecular characterization, expression analysis of the myostatin gene and its association with growth traits in sea cucumber (Apostichopus japonicus).

Myostatin (MSTN), also referred to as growth and differentiation factor-8 (GDF-8), is a member of the transforming growth factor-β superfamily (TGF-β) and an important negative regulator for skeletal muscle development and growth in vertebrates. However, its function is not clear in invertebrates. In this study, we cloned and analyzed the MSTN gene (Aj-MSTN) from sea cucumber (Apostichopus japonicus). The full-length cDNA sequence of Aj-MSTN gene was composed of 2912bp, which contained a 5' UTR of 487bp, an ORF of 1356bp encoding 452 amino acids and a 3' UTR of 1069bp. The structure of Aj-MSTN included a putative signal peptide, a TGF-β propeptide domain and a conserved TGF-β domain. Phylogenetic analysis showed that the Aj-MSTN gene was clustered in the same subgroup with the MSTN-like gene found in Strongylocentrotus purpuratus. Quantitative real-time PCR detection results indicated that the Aj-MSTN gene expressed widely in adult tissues and the highest expression level was observed in the body wall. At different developmental stages, the expression levels were increased significantly at early auricularia and doliolaria stages, and reached the peak at juvenile stage. Six SNPs were identified in 5' flanking region and exons of the Aj-MSTN gene. Association analysis showed that SNP-1, SNP-2 and SNP-4 had significant effects on dry body weight. The results suggested that Aj-MSTN gene could be used as a candidate gene for the selective breeding of A. japonicus.