Body Growth Rate Research Articles

Effect of dietary phenylpropanoid glycoside-based natural extracts on blood parameters and productive performance in intensively-reared young hares

Two different doses of a dietary verbascoside-based supplement were evaluated on various blood parameters and on productive performance in young weaned hares reared intensively from 28 to 90 days of age. The study lasted for 62 days and it was conducted on 210 young hares divided into three homogeneous groups of 70 animals each, consisting of a control group and two experimental groups. Each group received the dietary supplement in the feed, titrated to 0.5% verbascoside, 1 kg/t of concentrate (LVB group) and 2 kg/t of concentrate (HVB group). The experimental reliefs included the measurement of blood parameters such as triglycerides, total cholesterol, high density lipoprotein cholesterol, and bilirubin, along with some markers of oxidative status in plasma such as reactive oxygen metabolites, thiobarbituric acid-reactive substances, and vitamins A and E. Various productive parameters were also measured such as body weight and growth rate, food consumption, and feed conversion. The experimental treatment resulted in a significant decrease in triglycerides (P < 0.01) and bilirubin (P < 0.05) and an increase in high density lipoprotein cholesterol (P < 0.01) both in the low verbascoside (LVB) and high verbascoside (HVB) experimental groups. In addition, the oxidative plasma stability in blood also improved, with a significant decrease in the concentration of reactive oxygen metabolites (P < 0.01) and thiobarbituric acid-reactive substances (P < 0.01), along with increased levels of vitamin E (P < 0.05). The productive performance was not statistically influenced by the experimental treatment, except for the growth rate which increased significantly (P < 0.05) in the experimental LVB and HVB groups: 6.9% and 8.7% respectively compared with the control group. 

Distribution and biometry of native and alien crayfish in Trentino (Italian Alps)

To fill the existing gaps in the knowledge of the crayfish species distribution in Trentino region (North-East Italy), we surveyed fourteen lakes, six ponds and sixty-nine creeks and streams in 2010-2012. We recorded four populations of the invasive alien species Orconectes limosus in four lakes and twenty of the native Austropotamobius pallipes complex from four lakes, three ponds and thirteen creeks; three of these populations went extinct during the three years of our survey. Crayfish populations were monitored in spring, summer and early autumn, to assess the distribution, density and seasonal dynamics of the two species. Statistical analysis of morphometric data showed differences in body size and growth rates among sampling sites, possibly related to local environmental factors, with higher growth rates in males of both species; A. pallipes grew faster in creeks than in lakes. The extinction of twenty-two native populations of A. pallipes complex in the last century was likely due to habitat modifications, in particular to the loss of riparian habitat, in few cases to overfishing, and, more recently, to the spread of alien species and the related transmission of their parasite Aphanomyces astaci . Some populations of A. pallipes complex were infested with the parasite Thelohania sp ., and only one population with ectosymbiotic Branchiobdellida. In Trentino, small creeks with well developed riparian vegetation and good hydromorphological conditions, flowing through mountain slopes, can represent potential refuge and recruitment areas for of A. pallipes complex, without significant management intervention, although a sustainable management of piedmont water bodies would allow preserving or increasing the number and density of the relict populations.

Body chemical composition of Nellore bulls with different residual feed intakes1

Empty body and carcass chemical compositions, expressed as content of water, ether extract, protein, minerals, and energy, were evaluated in Nellore bulls with different residual feed intakes (RFI). Forty-nine not castrated males, with 343 kg of average initial BW and 398 kg of average slaughter BW, were studied. Animals were divided in two subgroups: reference group (RG) and ad libitum feeding group. At the end of the adaptation period, animals of subgroup RG were slaughtered and the other animals were finished in individual pens for approximately 100 d, until they reached a subcutaneous fat thickness over the LM of 4 mm, and were slaughtered at an average age of 540 d. Body composition was obtained after grinding, homogenizing, sampling, analyzing, and combining blood, hide, head + feet, viscera, and carcass. Tissue deposition rates and chemical composition of gain were also measured based on gains estimated by comparative slaughter technique. No significant differences in slaughter BW (P = 0.8639), empty BW (P = 0.7288), HCW (P = 0.6563), or empty body and carcass rates of gain were observed between RFI groups, demonstrating that the low (-0.331 kg DM/d) and high (+0.325 kg DM/d) RFI animals presented similar body sizes and growth rates. No significant differences in empty body or carcass content of water, ether extract, protein, minerals, and energy were observed between the low and high RFI animals. And also there were no significant differences in empty BW or carcass gain, demonstrating that low and high RFI animals had a similar growth potential. More efficient animals (low RFI) consumed less feed than less efficient animals (high RFI) but presented similar body sizes, growth rates, and empty body and carcass chemical composition.

Melanism, body condition and elevational distribution in the asp viper

AbstractAlternative morphotypes can confer important selective advantages in different habitats, whereas they can be penalized in other circumstances. In ectotherms, such as reptiles, the body colour can have direct effects on numerous aspects of their existence, such as thermoregulation or prey–predator interactions. Darker melanic individuals show lower skin reflectance and consequently heat up more rapidly and maintain optimal body temperatures more easily than lighter coloured individuals. As a consequence, melanistic individuals of diurnal species in cool areas may exhibit higher body condition, growth rate, survival and fecundity than lighter coloured individuals. Such advantages of dark coloration may be counterbalanced by a lower crypsis to predators and a decreased foraging efficiency. We investigated, in two montane populations of asp vipers Vipera aspis, the relationship between (1) colour polymorphism and body condition and length and (2) the coloration of individuals and their elevational distribution. We showed significant relationships between (1) the coloration, body condition and sex of individuals; (2) sexes and reproductive state and morph frequency; and (3) colour morphs that were distributed following an elevational gradient. Hence, colour polymorphism plays an important role in the ecology and evolution of the asp viper and is maintained through differential selective pressures.

Quantitative trait loci (QTL) associated with growth rate trait in common carp (Cyprinus carpio)

Growth rate is one of the important economic traits in aquaculture species that is influenced by quantitative trait loci (QTLs). Recently published complete genetic map of common carp (Cyprinus carpio) with 307 markers (including 109 SSR, 31 EST-SSR and 167 SNP markers) was used to determine the number and position of QTLs effecting body weight (BW) and growth rate. Ten-, 11- and 12-month-old individuals of common carp were measured, and seven QTLs were detected in three linkage groups (LG1, LG6 and LG20); three were significant QTLs (qBW2-6, qBW3-6 and qBW3-20, P < 0.001), and four were suggestive QTLs (qBW1-1, qBW1-6, qBW2-20 and qBW3-1, P < 0.01). The three significant QTLs related to BW2 and BW3 were in LG6 and LG20 and covered 18 and 41 cM, respectively. The explained variances of qBW2-6, qBW3-6 and qBW3-20 were 34.4, 32.1 and 33.4 %, respectively. The four suggestive QTLs affecting BW1, BW2 and BW3 were in LG1, LG6 and LG20 and had variances that ranged from 17.9 to 26.7 %. The similarity of the QTL intervals for BW1, BW2 and BW3 in LG6 suggested that these genes may affect growth continuously during the early stage of growth and may be important for growth. The identification of QTLs for growth rate and BW in C. carpio will lead to a better understanding of the factors that influence these traits at a genetic level and will promote the growth to higher production through marker-assisted breeding.

Comparative analysis of quantitative trait loci for body weight, growth rate and growth curve parameters from 3 to 72 weeks of age in female chickens of a broiler–layer cross

BackgroundComparisons of quantitative trait loci (QTL) for growth and parameters of growth curves assist in understanding the genetics and ultimately the physiology of growth. Records of body weight at 3, 6, 12, 24, 48 and 72 weeks of age and growth rate between successive age intervals of about 500 F2 female chickens of the Roslin broiler-layer cross were available for analysis. These data were analysed to detect and compare QTL for body weight, growth rate and parameters of the Gompertz growth function.ResultsOver 50 QTL were identified for body weight at specific ages and most were also detected in the nearest preceding and/or subsequent growth stage. The sum of the significant and suggestive additive effects for bodyweight at specific ages accounted for 23-43% of the phenotypic variation. A single QTL for body weight on chromosome 4 at 48 weeks of age had the largest additive effect (550.4 ± 68.0 g, 11.5% of the phenotypic variation) and a QTL at a similar position accounted 14.5% of the phenotypic variation at 12 weeks of age. Age specific QTL for growth rate were detected suggesting that there are specific genes that affect developmental processes during the different stages of growth. Relatively few QTL influencing Gompertz growth curve parameters were detected and overlapped with loci affecting growth rate. Dominance effects were generally not significant but from 12 weeks of age they exceeded the additive effect in a few cases. No evidence for epistatic QTL pairs was found.ConclusionsThe results confirm the location for body weight and body weight gain during growth that were identified in previous studies and were consistent with QTL for the parameters of the Gompertz growth function. Chromosome 4 explained a relatively large proportion of the observed growth variation across the different ages, and also harboured most of the detected QTL for Gompertz parameters, confirming its importance in controlling growth. Very few QTL were detected for body weight or gain at 48 and 72 weeks of age, probably reflecting the effect of differences in reproduction and random environmental effects.

Early ontogeny of the mackerel icefish, Champsocephalus gunnari, in the southern Scotia Arc

During the early ontogeny of fishes, the timing and duration of key events such as larval hatching and the switch from endogenous to exogenous feeding largely determine the offspring viability and survival. The aim of the present study was to investigate the life history traits of the early larvae of the mackerel icefish, Champsocephalus gunnari, collected in summer south of the South Shetland Islands in the Bransfield Strait and north of Elephant Island. Through the analysis of sagittal otolith microstructure, we assessed the timing and duration of egg incubation, larval hatching, first exogenous feeding, rate of yolk resorption and body growth rate. Compared to populations living further north (i.e. around South Georgia and Kerguelen Islands), mackerel icefish in the southern Scotia Arc exhibits longer egg incubation (lasting 90–120 days from winter to summer) and delayed hatching time spread over a relatively short period lasting 26 days between January and February. The first exogenous feeding takes place between 13 and 24 days after hatching still in the presence of the yolk-sac, indicating a prolonged mixed feeding afterward. The specific growth rate or daily percentage change in size (G) was 1.9 % SL day−1, corresponding to a daily growth rate at mean size of 0.31 mm day−1. While showing significant differences in early life history traits across their geographical distribution, C. gunnari populations share a common strategy, spawning a small number of large eggs that hatch in relatively large-sized larvae, at a time which may be independent of the timing of pack-ice retreat and onset of the production cycle.

Invader impact clarifies the roles of top‐down and bottom‐up effects on tropical snake populations

Summary Disentangling the effects of prey limitation (bottom‐up) and predation (top‐down) processes on natural populations is difficult, but the perturbations introduced by an invasive species can provide pseudo‐experimental evidence on this issue. In tropical Australia, keelbacks (Tropidonophis mairii) and slatey‐grey snakes (Stegonotus cucullatus) experience little direct cost or benefit from the arrival of toxic invasive cane toads (Rhinella marina), because they rarely eat toads and if they do, are relatively resistant to the toads' toxins. Nonetheless, these snakes could be affected indirectly by toad‐induced decreases in the availability of prey (native frogs) and/or by fatal poisoning of the snakes' predators (large varanid lizards). The former (bottom‐up) effect predicts decreases in snake body condition, feeding and growth rates after toads arrive, whereas the latter (top‐down) effect predicts increases in survival. Our mark–recapture studies on these snakes in tropical Australia (for 7 years before and 7 years after toad arrival) reveal bottom‐up effects both on an anurophagous dietary specialist (keelbacks) and a generalist feeder (slatey‐grey snakes). Top‐down effects of toad arrival were seen in keelbacks but not in slatey‐grey snakes, perhaps reflecting the latter's larger body size. Indirect effects coinciding with the timing of toad invasion thus were mediated through changes in food supply for both native species and in rates of predation for one species.

Trait contributions to fish community assembly emerge from trophic interactions in an individual-based model

Community ecology seeks to understand and predict the characteristics of communities that can develop under different environmental conditions, but most theory has been built on analytical models that are limited in the diversity of species traits that can be considered simultaneously. We address that limitation with an individual-based model to simulate assembly of fish communities characterized by life history and trophic interactions with multiple physiological tradeoffs as constraints on species performance. Simulation experiments were carried out to evaluate the distribution of 6 life history and 4 feeding traits along gradients of resource productivity and prey accessibility. These experiments revealed that traits differ greatly in importance for species sorting along the gradients. Body growth rate emerged as a key factor distinguishing community types and defining patterns of community stability and coexistence, followed by egg size and maximum body size. Dominance by fast-growing, relatively large, and fecund species occurred more frequently in cases where functional responses were saturated (i.e. high productivity and/or prey accessibility). Such dominance was associated with large biomass fluctuations and priority effects, which prevented richness from increasing with productivity and may have limited selection on secondary traits, such as spawning strategies and relative size at maturation. Our results illustrate that the distribution of species traits and the consequences for community dynamics are intimately linked and strictly dependent on how the benefits and costs of these traits are balanced across different conditions.

Ameliorative Potentials of Cocoyam (Colocasia Esculenta L.) and Unripe Plantain (Musa Paradisiacal L.) in Renal and Liver Growth in Streptozotocin Induced Diabetic Rats

The ameliorating potentials of cocoyam (Colocasia esculenta L.), ginger (Z.officinale Roscoe) and unripe plantain (Musa paradisiacae L.) incorporated feeds on the relative pancreatic weights of streptozotocin induced diabetic rats was investigated. The blood glucose level of all the rats was measured with a glucometer, the assay of the phytochemical and crude fibre compositions of the test feeds were carried out using standard techniques. The administration of the test feeds for 21 days to the diabetic rats of groups 5 to 7, resulted in 58.75%, 29.81% and 38.13% decreases in their hyperglycemia. Administration of the cocoyam incorporated feeds to the diabetic rats of group 5, resulted in 2.71% and 19.52% increases in their body weights and growth rates respectively, administration of the ginger incorporated feeds to the diabetic rats of group 6, resulted in 9.88% and 60.24% increases in their body weights and growth rates, unlike the diabetic rats of group 7, administered unripe plantain feed that had 5.12% decrease in weight with a corresponding 29.52% decrease in growth rate but higher than the diabetic control rats that recorded 28.69, 28.62% and 29.46% decreases in body weights with corresponding 248.9%, 239.9% and 250.14% decreases in growth rates. Chemical analysis of the test feeds indicate that they contained considerable amounts of phytochemicals and crude fibre. Results indicate the ability of cocoyam, ginger and unripe plantain to ameliorate the relative pancreatic weight of diabetics.

Assessment of Growth Rate of UDA Sheep Fed Diets Containting Varying Energy Levels Using Live Morphometry

A study was conducted to evaluate varying energy levels on growth rate of sheep using live morphometric measurements. Twenty growing Uda lambs were randomly allocated into four dietary treatments (five animals per treatment) with varying energy levels in a completely randomized experimental design (CRD). The animals were fed diets containing 1800, 2000, 2200 and 2400 kcals ME/kg. Data were collected on feed intake, live weight gain and body morphometric indices. The findings of the study revealed that dry matter intake, live weight gain and growth rate increased with increasing energy level (P 0.05). Relationship between the body measurements and initial live weight of the animals was not significant (P> 0.05). Except for knee to floor and hock to floor heights, live weight and body measurements of the animals were highly significant with the final live weight (P<0.01). It was concluded that the optimum energy level for body gain and growth rate of sheep is 2200kcals ME/ kg.

Relation between Parasitism, Stress, and Fitness Correlates of the Eastern Foxsnake (Pantherophis gloydi) in Ontario

We investigated the relation between heterophil/lymphocyte ratios, hepatozoon parasitemia, and two presumed fitness correlates (residual body condition and growth rate) in two regional populations of the Eastern Foxsnake, Pantherophis gloydi. Parasite intensity was not related to either fitness correlate. We found a significant relationship between log (heterophil to lymphocyte [H/L] ratio) and residual growth rate for individuals from Georgian Bay, but not those from southwestern Ontario. There was no significant relationship between log (H/L ratio) and residual body condition in either regional population. We also detected dramatic differences in parasite prevalence and H/L ratios between the two populations: Almost half of the sampled individuals from Georgian Bay were infected with hepatozoons compared to only 2 of 46 infected individuals from southwestern Ontario; H/L ratios were significantly higher in Georgian Bay individuals implying that individuals in this northern population experience higher levels of stress than those in southern Ontario where the environment differs markedly.

Early development and allometric growth in hatchery-reared characinBrycon orbignyanus

The characin piracanjuba, Brycon orbignyanus (Valenciennes, 1850), has been recognized as a candidate species for aquaculture. The early morphological development and allometric growth of hatchery-reared piracanjuba were studied from hatching to the juvenile stage, at water temperature of 27.9 ± 0.6°C. Growth, in total length (TL), was linear during that period. At hatching (3.4 ± 0.2 mm TL), the non-pigmented free embryo had most functional systems not fully differentiated. The primordial finfold was almost completely absorbed, except the preanal segment, in individuals measuring 9.1 ± 0.4 mm TL. Retinal pigmentation occurred as early as 24 hours posthatching (hph). The yolk sac was no longer observed after 60 hph. Body proportion and growth rates changed considerably during early morphological development. The head experienced positive allometric growth in length throughout the interval of study, and at the inflexion point of 6.6 mm TL, head growth had reduced significantly, but still remained allometrically positive. Trunk length showed negative allometric growth throughout the period of study. The growth of the postanal length was allometrically positive until the inflexion point at 7.1 mm TL, and thereafter decreased to near isometric. The allometric growth changes in the piracanjuba during initial life likely result from selective organogenesis directed towards survival priorities.

Measurement of changes in body composition of piglets from birth to 4 kg using quantitative magnetic resonance (QMR)*

Abstract. The purpose of this study was to use quantitative magnetic resonance (QMR) to measure changes in the body composition of piglets during growth from birth to 4 kg body weight. Using QMR, 60 pigs were scanned an average of 5 times starting at 2.7±1.3 days of age (1.95 kg) and finally at 13.1±4.3 days (4.14 kg). Regression analysis revealed that the rates of total body growth and fat and lean deposition were linear throughout this period. Subsequently, a second group of 235 pigs (109 males and 126 females) were scanned twice, first at 2.7±1.2 days of age and then at 13.4±3.1 days of age. The mean (±SD) rate of total body growth was 230±57 g/day. The rates of fat and lean deposition were 40±13 g/day and 191±52 g/day, respectively. The rates of both fat and lean deposition were highly correlated (P&lt;0.001) with total body growth rate (R2=0.81 and 0.93, respectively) and the coefficient of determination between the rates of fat and lean deposition was 0.71 (P&lt;0.001). The results of this study demonstrate that QMR is a useful method for measuring changes in body composition in neonatal pigs. Furthermore, the results indicate that during the period of growth from birth to 4 kg, the rates of both fat and lean deposition are linear and highly correlated with total body growth.

Body composition of piglets exhibiting different growth rates

Abstract. The growth and composition of the neonatal pig is of interest because of potential impact on subsequent growth and finally, composition at market weight. The purpose of this study was to compare at weaning the growth and body composition of the largest and smallest pigs from each of 38 litters. At weaning (27±1.7 d) the largest (9.3±1.1 kg) and smallest (6.2±1.5 kg) pigs were selected for body composition measurement by dual energy X-ray absorptiometry (DXA). The body composition of the largest pigs consisted of 38 % more fat, 32 % more lean, and 29 % more bone mineral content (P&lt;0.001). However, when expressed as a percentage of body weight, there was no difference in the fat, lean or bone mineral content content of the two groups of pigs (P&gt;0.05). A second study consisted of 12 pairs of pigs from 8 litters that were selected on the basis of having the same birth weight, but one pig out gaining the other by at least 50 g/day. At 21 days of age the selected pigs were scanned by DXA. For both groups combined, the correlation (r) between body weight and lean mass was 0.99, between body weight and fat mass it was 0.87, and between body weight at birth and body weight at weaning it was 0.56. The results of these studies revealed that, at weaning, the fastest and slowest growing pigs had similar proportions of fat, lean and bone mineral and, consistent with previous results, the rates of both fat and lean deposition were highly correlated (P&lt;0.001) with total body growth rate.

Lack of brain serotonin affects postnatal development and serotonergic neuronal circuitry formation

Despite increasing evidence suggests that serotonin (5-HT) can influence neurogenesis, neuronal migration and circuitry formation, the precise role of 5-HT on central nervous system (CNS) development is only beginning to be elucidated. Moreover, how changes in serotonin homeostasis during critical developmental periods may have etiological relevance to human mental disorders, remains an unsolved question. In this study we address the consequences of 5-HT synthesis abrogation on CNS development using a knock-in mouse line in which the tryptophan hydroxylase 2 (Tph2) gene is replaced by the eGFP reporter. We report that lack of brain 5-HT results in a dramatic reduction of body growth rate and in 60% lethality within the first 3 weeks after birth, with no gross anatomical changes in the brain. Thanks to the specific expression of the eGFP, we could highlight the serotonergic system independently of 5-HT immunoreactivity. We found that lack of central serotonin produces severe abnormalities in the serotonergic circuitry formation with a brain region- and time- specific effect. Indeed, we observed a striking reduction of serotonergic innervation to the suprachiasmatic and thalamic paraventricular nuclei, while a marked serotonergic hyperinnervation was found in the nucleus accumbens and hippocampus of Tph2∷eGFP mutants. Finally, we demonstrated that BDNF expression is significantly up-regulated in the hippocampus of mice lacking brain 5-HT, mirroring the timing of the appearance of hyperinnervation and thus unmasking a possible regulatory feedback mechanism tuning the serotonergic neuronal circuitry formation. On the whole, these findings reveal that alterations of serotonin levels during CNS development affect the proper wiring of the brain that may produce long-lasting changes leading to neurodevelopmental disorders.

Responses of yellow catfish (Pelteobagrus fulvidracoRichardson) to low-protein diets and subsequent recovery

A 4-week growth trial was conducted to investigate the effect of low-protein diets on the growth and amino acid (AA) composition of yellow catfish, and subsequent recovery when the fish were then switched back to the control diet for a further 4weeks. Three isolipidic and isocaloric diets containing 390gkg1 (Control), 320gkg1 (D320) and 260gkg1 (D260) graded protein levels were evaluated. During the protein restriction period, specific growth rate (SGR) of D320-and D260-treated fish was significantly reduced by 20.79% and 29.21% compared to the control fish, respectively (P<0.05), while significant improvements in protein retention efficiencies were observed in fish fed with the D320 (12.82%) and D260 (19.58%) diets (P<0.05). The D260-treated fish had significantly lower (0.87%) whole-body essential amino acid (EAA) and significantly higher (0.74%) non-essential amino aci (NEAA) concentrations compared to the control fish. After a 4-week realimentation, significant increases in the SGR of the protein-restricted fish were observed. However, no significant differences in the whole-body EAA or NEAA concentrations among groups were observed (0.05). The results indicate that previously protein-restricted yellow catfish can compensate completely in terms of final body weight, growth rate and whole-body AA concentrations.

The estimation of (co)variance components and genetic parameters for growth traits and Kleiber ratios in Malpura sheep of India

Objective of the present study was to estimate the genetic parameters and (co)variance components for different economic traits in Malpura sheep. The traits analyzed were birth weight (BWT), weaning weight (WWT), 6-month weight (6WT), average daily gain from birth to weaning (ADG1), average daily gain from weaning to 6-month (ADG2), average daily gain from birth to 6-month (ADG3), Kleiber ratio from birth to weaning (KR1), Kleiber ratio from weaning to 6-month (KR2) and Kleiber ratio from birth to 6-month (KR3). Six different animal models including or ignoring maternal genetic or permanent environmental effects were fitted for all traits. Akaike information criterion (AIC) was applied to determine the most appropriate model for each trait. For BWT, WWT, 6WT, ADG1, ADG2 and KR2 the model including permanent environmental effects due to ewe over direct genetic effects was the most appropriate. Model which included only direct genetic effects was the best model for ADG3, KR1 and KR3. Direct heritability estimates of 0.21, 0.24, 0.23, 0.23, 0.13, 0.22, 0.20, 0.12 and 0.23 were obtained for BW, WW, 6MW, ADG1, ADG2, ADG3, KR1, KR2 and KR3, respectively. Ratios of phenotypic variance due to maternal permanent environmental effects were 0.24, 0.07, 0.01, and 0.05 for BW, WWT, 6WT and ADG1, respectively. Estimates of direct genetic correlation were very low to high in magnitude and varied from −0.27 for BW–KR2 to 0.97 for ADG1–KR1. Estimates of phenotypic correlation were very low to high in magnitude and varied from −0.27 for WW–KR2 to 0.96 for ADG3–KR3. The moderate estimate of direct heritability for body weight, growth rate and Kleiber ratio suggests that Malpura sheep can be improved through selection for economic mutton production.

Altitudinal Variation in Age and Body Size in Yunnan Pond Frog (Pelophylax pleuraden)

Large-scale systematic patterns of body size are a basic concern of evolutionary biology. Identifying body size variation along altitudinal gradients may help us to understand the evolution of life history of animals. In this study, we investigated altitudinal variation in body size, age and growth rate in Chinese endemic frog, Pelophylax pleuraden. Data sampled from five populations covering an altitudinal span of 1413 to 1935 m in Sichuan province revealed that body size from five populations did not co-vary with altitudes, not following Bergmann's rule. Average adult SVL differed significantly among populations in males, but not in females. For both sexes, average adult age differed significantly among populations. Post-metamorphic growth rate did not co-vary with altitude, and females grew faster than males in all populations. When controlling the effect of age, body size did not differ among populations in both sexes, suggesting that age did not affect variation in body size among populations. For females, there may be other factors, such as the allocation of energy between growth and reproduction, that eliminated the effect of age on body size. To our minds, the major reason of body size variation among populations in male frogs may be related to individual longevity. Our findings also suggest that factors other than age and growth rate may contribute to size differences among populations.

Maternal Use of Selective Serotonin Reuptake Inhibitors, Fetal Growth, and Risk of Adverse Birth Outcomes

Selective serotonin reuptake inhibitors (SSRIs) are frequently prescribed to pregnant women, but knowledge about their unintended effects on child health is scarce. To examine the effects of maternal SSRI use during pregnancy on fetal growth and birth outcomes. The study was embedded in the Generation R Study, a prospective population-based study from fetal life onward. Seven thousand six hundred ninety-six pregnant women were included. Selective serotonin reuptake inhibitor use was assessed by questionnaires in each trimester and verified by pharmacy records. Using depressive symptom scores from the Brief Symptom Inventory, 7027 pregnant mothers (91.3%) had no or low depressive symptoms, 570 pregnant mothers (7.4%) had clinically relevant depressive symptoms and used no SSRIs, and 99 pregnant mothers (1.3%) used SSRIs. Fetal ultrasonography was performed in each trimester. We determined fetal body and head growth with repeated assessments of body and head size. The birth outcomes studied were preterm birth, small for gestational age, and low birth weight. Fetuses from mothers with prenatal depressive symptoms showed reduced body growth (β=-4.4 g/wk; 95% CI: -6.3 to -2.4; P<.001) and head growth (β=-0.08 mm/wk; 95% CI: -0.14 to -0.03; P=.003). Mothers using SSRIs during pregnancy had fewer depressive symptoms than mothers in the clinical symptom range. Prenatal SSRI use was not associated with reduced body growth but was associated with reduced fetal head growth (β=-0.18 mm/wk; 95% CI: -0.32 to -0.07; P=.003). The SSRI-exposed children were at higher risk for preterm birth (odds ratio=2.14; 95% CI: 1.08 to 4.25; P=.03). Untreated maternal depression was associated with slower rates of fetal body and head growth. Pregnant mothers treated with SSRIs had fewer depressive symptoms and their fetuses had no delay in body growth but had delayed head growth and were at increased risk for preterm birth. Further research on the implications of these findings is needed.