Showing papers on "Compensatory growth (organism) published in 2018"

Challenges of beef cattle production from tropical pastures

Abstract: The live weight gain of cattle on tropical pastures is reviewed and found to be low and dependent on the length of the growing season. Supplements may be added to address the primary limiting nutrient, which, in the dry season, is crude protein. The response relationships of live weight gain to level of supplement (protein or energy) that have been developed for animals on pasture in Brazil and Australia have been compared and found to be very similar. This gives confidence in recommending a supplementation strategy for cattle on tropical pastures. Response in the wet season was very low and likely to be uneconomic compared with dry season supplementation. Supplementation is costly and should only be used as a last resort, but the strategy needs to be viewed in the context of a growth path to a defined market or slaughter weight. In Australia, high inputs in the first dry season are risky as subsequent compensatory growth can reduce or eliminate the weight advantage of a supplement. There is less financial risk in using supplements towards the end of the growth path. Growth paths can follow many forms and there is no need to maximise live weight gain in each period. Targeted supplements in the second dry season, leucaena based systems, other special-purpose pastures or crops, and feedlots offer the most economical way for cattle to meet market targets. The expected annual live weight gain and weaning weight are other major factors which determine the growth path, target market which can be achieved, and the level of intervention (supplements, legumes, feedlots, etc) which are required and when. Some recent results on growth paths in Australia are presented.

Adaptive maternal behavioral plasticity and developmental programming mitigate the transgenerational effects of temperature in dung beetles

Abstract: 1 –––––––––––––––––––––––––––––––––––––––– © 2018 The Authors. Oikos © 2018 Nordic Society Oikos This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Subject Editor: Morgan Kelly Editor-in-Chief: Dries Bonte Accepted 12 March 2018 00: 1–11, 2018 doi: 10.1111/oik.05215 doi: 10.1111/oik.05215 00 1–11

Carry-over effects of early thermal conditions on somatic and germline oxidative damages are mediated by compensatory growth in sticklebacks

Abstract: Most studies of climate change impacts focus on the effects of summer temperatures, which can immediately impact fitness of breeders, but winter temperatures are expected to have a greater impact on development and growth of animals with long-lasting consequences. Exposure to warmer temperatures can increase cellular oxidative damage in ectotherms. Yet, it is unknown whether thermal stress during early life has prolonged effects on oxidative status during adulthood. In an experiment using F1 fish originated from a wild three-spined stickleback population at the southern edge of its European distribution, we examined whether experimental thermal conditions experienced in winter had carry-over effects on oxidative status and telomere length, a marker of accumulated stress, in the soma and germline during adulthood. For this, oxidative DNA damage, enzymatic antioxidant activities and telomere length were measured three months after the termination of the temperature manipulation. In addition, we tested whether such delayed effects, if any, were due to individuals' compensatory growth after experiencing unfavourable growth conditions in winter. Warm acclimation during winter induced increased levels of oxidative DNA damage in muscle and sperm and increased enzymatic antioxidant defences in muscle during the breeding season. Telomere length of adult fish was not influenced by thermal conditions experienced during early life. Winter temperature manipulation influenced fish to alter the temporal pattern of growth trajectories across the juvenile and adult stages. Fish reared in warm winter conditions grew at a slower rate than the controls during the period of temperature manipulation then accelerated body mass gain to catch up during the breeding season. Faster somatic growth during the breeding season incurred a higher cost in terms of oxidative damage in the warm-treated individuals. For the first time, we experimentally show the long-lasting detrimental effects of thermal stress on and the positive link between catch-up growth and oxidative DNA damage in the soma and germline. Winter temperature increases due to climate change can reduce fertility and survival of fish by inducing catch-up growth. The detrimental effects of winter climate change may accumulate across generations through the pre-mutagenic DNA damage in the germline.

Compensatory growth and feed restriction in marine shrimp production, with emphasis on biofloc technology

Abstract: In Brazil, studies and production of penaeid shrimp in a biofloc technology (BFT) system are recent, but the results point to a promising future. Research with feed restriction inducing compensatory growth in shrimps has been shown to be a technique that allows a saving of around 25% in the use of feed for shrimp production. It also allows the reduction of costs with salaries and adapts shrimp farming to the world demand for environmentally friendly production, with the reduction of nitrogen and phosphorus levels in its effluents, as well as lower water use in shrimp farming. In crustaceans, it has been shown that after a period of feed restriction, the animals show a pronounced compensatory growth when they return to a sufficient food source. Studies with the penaeid shrimp Litopenaeus vannamei reported the ability of the species to obtain a complete compensatory growth after short feeding periods (1 to 3 days) followed by feeding; These short periods of fasting presented a greater efficiency in the feed conversion besides the decrease in the concentration of phosphorus present in the aquatic environment, coming from the excreta. The adoption of a restriction program in the feeding using BFT may contribute to a reduction in operating costs, reduction of metabolic nutrients dissolved in water, and, consequently, an increase in the number of cycles in which the same water can be reused for production reducing production costs and improving productivity indices in shrimp farming.

Metabolic response to hypoxia in European sea bass (Dicentrarchus labrax) displays developmental plasticity

Abstract: Several physiological functions in fish are shaped by environmental stimuli received during early life. In particular, early-life hypoxia has been reported to have long-lasting effects on fish metabolism, with potential consequences for fish life history traits. In the present study, we examine whether the synergistic stressors hypoxia (40% and 100% air saturation) and temperature (15° and 20 °C), encountered during early life, could condition later metabolic response in European sea bass ( Dicentrarchus labrax ) juveniles. Growth rate and metabolic parameters related to carbohydrate and lipid metabolism in the liver were investigated at the juvenile stage under normoxic and chronic hypoxic conditions. Juvenile growth rates were significantly lower ( p − 6 ) under hypoxic conditions and were not improved by prior early-life exposure to hypoxia. Growth was 1.3 times higher ( p − 3 ) in juveniles reared at 15 °C during the larval stage than those reared at 20 °C, suggesting that compensatory growth had occurred. Early-life exposure to hypoxia induced higher ( p − 6 ) glycogen stores in juveniles even though there was no apparent regulation of their carbohydrate metabolism. In the liver of juveniles exposed to chronic hypoxia, lower glycogen content combined with stimulation of phosphoenolpyruvate carboxykinase gene expression and higher lactate concentration indicated a stimulation of the anaerobic glycolytic pathway. Furthermore, hypoxia only induced lower ( p − 3 ) lipid content in the liver of juveniles that had experienced 15 °C at the larval stage. The present study provides evidence that environmental conditions experienced during early life shape the metabolic traits of D. labrax with potential consequences for juvenile physiological performance.

Changes in plant growth and seed production in wild lima bean in response to herbivory are attenuated by parasitoids

Abstract: Lima bean plants (Phaseolus lunatus) exhibit compensatory growth responses to herbivory. Among the various factors that have been identified to affect plant compensatory growth are the extent and type of tissue damage, the herbivore’s feeding mode and the time of damage. Another factor that can greatly impact plant responses to herbivory, but has been largely ignored in previous studies, is the action of parasitoids. In most cases, parasitoids halt or slow down the development of herbivorous hosts, which, can result in decreased leaf damage, thereby affecting plant responses and ultimately plant fitness. Here, we investigated the effects of two koinobiont parasitoids on the amount of leaf damage inflicted by the Southern armyworm Spodoptera latifascia to wild lima bean, and the consequences of this for plant growth and seed production in the field. We specifically tested the hypothesis that the action of parasitoids will reduce plant damage and that this reduction will alter plant growth responses and seed production. Indeed, we found that in the presence of parasitoids plants suffered less damage than plants with only herbivores. As a consequence, compensatory growth was reduced and more and heavier seeds were produced earlier in the season, compared to plants exposed to only herbivores.

Toleration games: compensatory growth by plants in response to enemy attack is an evolutionarily stable strategy

Abstract: Damage to plants from natural enemies is a ubiquitous feature of the natural world. Accordingly, plants have evolved a variety of strategies to deal with attack from enemies including the ability to simply tolerate attack. Tolerance often involves some form of compensatory response, such as the regrowth of tissues following damage. While ecological models of defence are common, there has been less effort to make predictions about the evolutionary stability of tolerance. Here, we present and experimentally test a game theoretic model of tolerance to herbivory. Plants in the model have a vector strategy which includes both root and shoot production, and herbivores in the model have a scalar strategy which is time spent foraging. The evolutionarily stable strategy (ESS) is the set of root growth, shoot growth and herbivore foraging which simultaneously maximizes all player's fitness. Compensatory growth is not guaranteed, but it may emerge as an ESS if it maximizes plant fitness. We also experimentally tested the model predictions using wheat and simulated herbivory by clipping 0, 15, 30, 45 or 60 % of shoot production, and measured root, shoot and fruit production at senescence. The model predicted that compensatory growth was often an ESS when herbivores were either above- or below-ground. Plants in the experiment followed model predictions. Specifically, plants produced more tissues than expected based on damage, and for 15 % damage this allowed them to maintain equal fitness compared to undamaged plants. The model allows for above- and below-ground herbivory to be modelled, and predicts their impact on whole plant growth and reproduction. For example, we can predict the effects of shoot damage on root growth. When combined with other advances in predicting plant ecology with evolutionary game theory, we anticipate that this will be a valuable tool for generating further testable hypotheses.

Effects of fasting and refeeding on protein and glucose metabolism in arctic charr.

Abstract: Refeeding, following a period of food deprivation will often lead to compensatory growth. Although many studies have focused on molecular mechanisms behind this accelerated growth response in fish, little is known on the roles of protein and metabolism. We also assessed, for the first time, the potential roles of miRNAs in regulating compensatory growth. Artcic charr, Salvelinus alpinus, a northern freshwater species, was deprived of food for 101 days and then fed to satiety for 126 days. The refeeding period resulted in compensatory growth, with a partial compensation of body mass. The feed deprivation period lead to a decrease in hepatosomatic index (HSI) and intestinal somatic index (ISI). HSI and ISI were then gradually replenished during early refeeding, following a lag phase prior to the compensatory growth response. mRNA transcripts regulating protein degradation via the autophagy pathway (Cathepsin D and Cathepsin L) in muscle were upregulated during feed restriction and downregulated after refeeding, which could allow for greater protein accretion in muscle, facilitating compensatory growth. Transcript levels from the ubiquitin proteasome pathway (Mafbx and Murf1) and the calpain system (Calpain 7 and Calpastatin) suggested that these pathways were not involved in regulating compensatory growth. Furthermore, we've shown that miRNAs (miR-29a and miR-223) could be involved in fish glycogen homeostasis during the early stages of refeeding. These findings provide a deeper understanding of the molecular mechanisms regulating growth in fish.

Growth responses of the common arctic graminoid Eriophorum vaginatum to simulated grazing are independent of soil nitrogen availability

Abstract: Plant compensatory growth responses to herbivory are mediated by soil fertility and can have significant feedbacks that affect overall ecosystem nutrient cycling. The sedge Eriophorum vaginatum is the dominant graminoid in arctic mesic tundra, and is heavily consumed by caribou. Here, we compare the principal compensatory growth models in explaining the impact of a single episode of simulated caribou grazing at two clipping intensities on E. vaginatum total growing season shoot production, nitrogen concentrations, and nitrogen pools, over two successive years across a soil nitrogen fertilisation gradient. The clipping treatments had no effect on shoot production in the growing season when they were applied, but substantially reduced growth in the following year. Surprisingly, these reductions were consistent across all levels of soil nitrogen availability. The Limiting Resource Model can best explain this legacy effect on production because it predicts alternate compensatory growth responses depending on whether or not the herbivory affects availability of the resource that most limits plant growth. Accordingly, our results suggest that shoot compensatory growth in the year after the clipping was limited by some resource other than nitrogen-probably internal carbohydrate reserves or soil phosphorus. The clipping treatments initially enhanced shoot nitrogen concentrations and pools, but shoot nitrogen pools had decreased by the end of the second year due to the legacy effect of reduced shoot production. Finally, inflorescence removal substantially stimulated new shoot production in both years. Together, our results suggest that herbivory can significantly enhance temporal and local spatial heterogeneity in graminoid growth and nitrogen cycling.

Dietary antioxidants, food deprivation and growth affect differently oxidative status of blood and brain in juvenile European seabass (Dicentrarchus labrax).

Abstract: Compensatory growth may increase molecular oxidative damage, which may be mitigated through the intake of dietary antioxidants. However, dietary antioxidants may also reduce concentration of antioxidant enzymes, which have a key role in regulating the oxidative status. Here we investigated whether feeding on a diet rich in antioxidants (vitamin E) enables juvenile European seabass (Dicentrarchus labrax) to catch up after a period of food deprivation with negligible effects on the oxidative stress to blood and brain as compared to fish feeding on a normal diet (i.e., not enriched in antioxidants). The results show that a higher intake in antioxidants favoured compensatory growth, but this came at a cost in terms of increased oxidative damage. Increased intake of antioxidants also resulted in changes in the activity of enzymatic antioxidant defences and increased protein oxidative damage in both brain and blood. In addition, food deprivation caused increased protein oxidative damage in brain. Our findings show that the beneficial effects of dietary antioxidants on growth may be offset by hidden detrimental effects and that different early life events affect different components of oxidative status of a given tissue.

Role of AMPK signalling pathway during compensatory growth in pigs

Abstract: The molecular basis of compensatory growth in monogastric animals has not yet been fully explored. Herewith, in this study we aim to determine changes in the pig skeletal muscle transcriptome profile during compensatory growth following a feed restriction period. A RNA-Seq experiment was performed with a total of 24 females belonging to a Duroc commercial line. Half of the animals received either a restricted (RE) or ad libitum (AL) diet during the first fattening period (60–125 d of age). After that, all gilts were fed ad libitum for a further ~30 d until the age of ~155 d, when animals were slaughtered and samples of gluteus medius muscle were harvested to perform RNA-Seq analyses and intramuscular fat content determination. During the period following food restriction, RE animals re-fed ad libitum displayed compensatory growth, showed better feed conversion rate and tended to deposit more subcutaneous fat than AL fed animals. Animals were slaughtered in the phase of accelerated growth, when RE animals had not completely compensated the performance of AL group, showing lower live and carcass weights. At intramuscular level, RE gilts showed a higher content of polyunsaturated fatty acids during the compensatory growth phase. The comparison of RE and AL expression profiles allowed the identification of 86 (ǀlog2Fold-Changeǀ > 1, padj < 0.05) differentially expressed (DE) genes. A functional categorization of these DE genes identified AMPK Signaling as the most significantly enriched canonical pathway. This kinase plays a key role in the maintenance of energy homeostasis as well as in the activation of autophagy. Among the DE genes identified as components of AMPK Signaling pathway, five out of six genes were downregulated in RE pigs. Animals re-fed after a restriction period exhibited a less oxidative metabolic profile and catabolic processes in muscle than animals fed ad libitum. The downregulation of autophagy observed in the skeletal muscle of pigs undergoing compensatory growth may constitute a mechanism to increase muscle mass thus ensuring an accelerated growth rate. These results reveal that the downregulation of AMPK Signaling plays an important role in compensatory growth in pigs.

Compensatory growth response in Oreochromis mossambicus submitted to short-term cycles of feed deprivation and refeeding.

Abstract: This study was designed to determine compensatory growth response of short-term starvation and refeeding cycles on Oreochromis mossambicus juveniles. A total of 360 juveniles were randomly divided into 12 tanks in triplicate groups. The control group (C) was fed three times a day to satiation. The feeding regimes of the other groups were designed as follows: 2 days deprivation /2 days refeeding (2DD2DRF), 2 days deprivation /3 days refeeding (2DD3DRF), and 2 days deprivation /4 days refeeding (2DD4DRF). After 60 days, only fish in 2DD4DRF group presented partial compensatory growth; no significant difference (P>0.05) was observed in the final weight (FW), and specific growth weight (SGR) compared to the control. Hepatosomatic index (HSI), viscerosomatic index (VSI), and condition factor (CF) was not affected by these feeding regimes. Furthermore, improved feed conversion ratio (FCR), and feed efficiency ratio (FER) were observed in 2DD4DRF fish, among groups. Feed intake (FI) was significantly lower (P<0.05) in starved fish compared to C. Meanwhile, muscle crude protein and lipid content in 2DD2DRF, and 2DD3DRF groups was significantly lower (P<0.05) compared to C and 2DD4DRF group. Compensatory growth response in 2DD4DRF presents possibilities for economic optimization in O. mossambicus production.

Digestive and locomotor capacity show opposing responses to changing food availability in an ambush predatory fish

Abstract: Metabolic rates vary widely within species, but little is known about how variation in the “floor” (i.e. standard metabolic rate in ectotherms; SMR) and “ceiling” (maximum metabolic rate; MMR) for an individual9s aerobic scope (AS) are linked with the digestive and locomotor function. Any links among metabolic traits and aspects of physiological performance may also be modulated by fluctuations in food availability. This study followed changes in SMR, MMR, and digestive and locomotor capacity in Southern catfish ( Silurus meridionalis ) throughout 15 days of food deprivation and 15 days of refeeding. Individuals down-regulated SMR during food deprivation and showed only a 10% body mass decrease during this time. While critical swim speed ( U crit ), was robust to food-deprivation, digestive function decreased after fasting with a reduced peak oxygen uptake during specific dynamic action (SDA) and prolonged SDA duration. During refeeding, individuals displayed rapid growth and digestive function recovered to pre-fasting levels. However, refed fish showed a lower U crit than would be expected for their increased body length and in comparison to measures at the start of the study. Reduced swimming ability may be a consequence of compensatory growth: growth rate was negatively correlated with changes in U crit during refeeding. Southern catfish down-regulate digestive function to reduce energy expenditure during food deprivation, but regain digestive capacity during refeeding, potentially at the cost of decreased swimming performance. The plasticity of maintenance requirements suggests that SMR is a key fitness trait for in this ambush predator. Shifts in trait correlations with food availability suggest that the potential for correlated selection may depend on context.

Full compensation of growth in salt-tolerant tadpoles after release from salinity stress

Abstract: The benefit of compensatory growth is to minimize the negative effects of stress experienced by organisms early in development once the conditions improve. Tadpoles of crab-eating frog Fejervarya cancrivora are euryhaline, have the highest salt tolerance among reported anuran species and may exhibit a different pattern of compensatory growth after stress release. We examined how F. cancrivora tadpoles responded and possibly recovered from salinity stresses. Specifically, we tested whether tadpoles expressed compensatory growth, what degree of compensation they expressed after release from salinity stress and whether the stage at and duration during which they experienced salt stress influenced the size at and time to metamorphosis of tadpoles. We found that the effects of salinity stress on the growth and development of tadpoles are quite different between early and late exposure to high salinity (LHH vs. LLH). Exposure to high salinity late in development (LLH) reduced growth but not the rate of development, resulting in smaller metamorphs but a similar time to metamorphosis when compared to the control treatment (LLL). By contrast, exposure to high salinity early in development (LHH) retarded rates of growth and development of tadpoles, but the resulting prolonged larval period enabled tadpoles to catch up and reach similar metamorphic sizes to LLL treatment metamorphs. Most importantly, tadpoles released from salinity stress (LHL) exhibited similar time to and size at metamorphosis when compared to the LLL tadpoles, suggesting that they can exhibit full compensation of growth. Compensatory growth may be a useful mechanism for F. cancrivora tadpoles inhabiting brackish habitats, allowing them to overcome the effects of dramatically increased salt levels by expressing catch-up growth when the salt stress ceases.

Assessing the capacity for compensatory growth in growth‐hormone transgenic coho salmon Oncorhynchus kisutch

Abstract: The effect of feed cycling (consisting of periods of starvation followed by periods of refeeding to satiation) on compensatory growth was evaluated in growth hormone transgenic and non-transgenic wild-type coho salmon Oncorhynchus kisutch. The specific growth rate (GSR ) of feed-restricted non-transgenic O. kisutch was not significantly different from the GSR of fully-fed non-transgenic O. kisutch during two refeeding periods, whereas the GSR of feed-restricted transgenic O. kisutch was significantly higher in relation to the GSR of fully-fed transgenic O. kisutch during the second refeeding period, but not during the first, indicating that growth compensation mechanisms are different between non-transgenic and growth-hormone (GH)-transgenic O. kisutch and may depend on life history (i.e. previous starvation). Despite the non-significant growth rate compensation in non-transgenic O. kisutch, these fish showed a level of body mass catch-up growth not displayed by transgenic O. kisutch.

Compensatory Growth of the Juvenile Brown Flounder Paralichthysolivaceus Following Being Kept at High Temperature for a Single Phase of Different Length

Abstract: Received date: September 09, 2017 Accepted Date: March 15, 2018 Published Date: March 20, 2018 1Guangxi Key Laboratoryof Marine Biotechnology, Guangxi Institute of Oceanology, Beihai 536000, China 2Ocean college, Qinzhou University, Qinzhou 535011, China 3Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China Journal of Marine Biology and Aquaculture

Dietary Restriction, Starvation, Compensatory Growth – ‘ Short-Term Fasting Does Not Kill You: It Can Make You Stronger ’

Abstract: In natural systems, short-term food deprivation (dietary restriction, DR; calorie restriction, CR) occurs frequently and animals have developed strategies to cope with this situation. This process has been in the focus of many ecological and aquacultural studies and will be discussed in this chapter. In general, life history theory assumes trade-offs in resource allocation among growth, self-maintenance and reproduction; complimentarily, evolutionary theory expresses the general expectation that DR will often result in improved survival probability, and extended life span. The response to DR is species-specific and often even specific to subpopulations or clones, and several aquatic species respond to DR with reduced life span and fecundity. In the case of life span extension, one major mechanism appears to be increased stress resistances which can even be passed to succeeding generations, most likely via epigenetic mechanisms. In model organisms, but not yet in fishes or aquatic invertebrates, major signaling pathways have been identified. Provided these mechanisms are better understood in fish and invertebrate species, broodstocks can intentionally be improved, instead of using the stochastic genetic approach.

Relative Mass of Brain- and Intestinal Tissue in Juvenile Brown Trout: No Long-Term Effects of Compensatory Growth; with Additional Notes on Emerging Sex-Differences

Abstract: This study investigated whether compensatory growth causes long-term effects in relative brain- or intestine size in a wild, predominantly anadromous, population of brown trout (Salmo trutta). The subject fish belonged to two treatment groups; one group had undergone starvation and subsequent growth compensation, while the other were unrestricted controls. The main hypothesis that compensatory growth would negatively affect brain and intestinal size, as a consequence of growth trade-offs during the compensatory phase, could not be supported as no significant differences were detected between the treatment groups. Further exploratory analyses suggested that males and females started to diverge in both brain and intestine size at around 130 mm fork length, with females developing relatively smaller brains and larger intestines. The size at which the differences appear is a typical size for smoltification (saltwater preadaptation), and females tend to smoltify to a higher proportion than males. Smoltification is known to cause a more elongated morphology and relatively smaller heads in salmonids, and the marine lifestyle is associated with rapid growth, which could require relatively larger intestines. Hence, these emerging sex differences could be a consequence of sex-biased smoltification rates. An investigation of wild smolts of both sexes indicated no differences in brain or intestine mass between male and female smolts.

Low genetic variation in tolerance to defoliation in a long-lived tropical understorey palm

Abstract: Defoliation is a ubiquitous stressor that can strongly limit plant performance. Tolerance to defoliation is often associated with compensatory growth. Genetic variation in tolerance and compensatory growth responses, in turn, play an important role in the evolutionary adaptation of plants to changing disturbance regimes but this issue has been poorly investigated for long-lived woody species. We quantified genetic variation in plant growth and growth parameters, tolerance to defoliation and compensatory responses to defoliation for a population of the understorey palm Chamaedorea elegans. In addition, we evaluated genetic correlations between growth and tolerance to defoliation. We performed a greenhouse experiment with 731 seedlings from 47 families with twelve or more individuals of C. elegans. Seeds were collected in southeast Mexico within a 0.7 ha natural forest area. A two-third defoliation treatment (repeated every two months) was applied to half of the individuals to simulate leaf loss. Compensatory responses in specific leaf area, biomass allocation to leaves and growth per unit leaf area were quantified. We found that growth rate was highly heritable and that plants compensated strongly for leaf loss. However, genetic variation in tolerance, compensation, and the individual compensatory responses was low. We found strong correlations between family mean growth rates in control and defoliation treatments. We did not find indications for growth-tolerance trade-offs: genetic correlation between tolerance and growth rate were not significant. The low genetic variation in tolerance and compensatory responses observed here suggests a low potential for evolutionary adaptation to changes in damage or herbivory, but high ability to adapt to changes in environment that require different growth rates. The strong correlations between family mean growth rates in control and defoliation treatments suggest that performance differences among families are also maintained under stress of disturbance.

Refilling temporary ponds has timing‐dependent effects on Hyla gratiosa performance

Abstract: Funding information The University of Mississippi; Henry L. and Grace Doherty Foundation Abstract 1. Disturbances and variation in abiotic habitat conditions greatly affect populations and communities. The multitude of processes that occur in natural systems offers the possibility that the trajectories of ephemeral habitats and the effects of disturbances can be slowed or reversed. Hydroperiod is a defining characteristic in freshwater systems, with temporary ponds supporting distinct communities of organisms with plastic developmental trajectories and complex lifecycles that allow them to cope with the vagaries of pond duration. 2. Despite work on the effects of pond drying on aquatic animals, little consideration has been given to filling, which can extend the duration of small, drying ponds. Our goal was to assess how increasing the volume of small ponds affects the developmental trajectories of larval amphibians living in these habitats. We conducted a field mesocosm experiment to assess how filling of ponds early, midway and late in the larval period affected the survival and development of the barking treefrog, Hyla gratiosa. We hypothesised that filling early in the larval stage would provide the most benefits, producing more and larger metamorphs than filling later in development. 3. We found that through various effects on survival, metamorphosis, habitat quality and competition, increasing volume early in development produced more and larger metamorphs with faster growth rates than any other treatment, whereas filling late in development produced few, small, slow growing metamorphs. 4. Our results provide support for the role of stressors in initiating metamorphosis and also show that increased pond volumes early in larval development can provide benefits to Hyla populations in terms of compensatory growth, but filling late in development has little benefit.

Gene networks contributing to compensatory growth in hepatic tissue in cattle

Abstract: Compensatory growth is an accelerated growth phenomenon observed in animals upon realimentation following a period of dietary restriction and is utilised worldwide in animal production systems as a method to lower feed costs. Gene co-expression network analysis was performed on the hepatic transcriptome of cattle that had undergone compensatory growth. The relationship between modules of co-expressed genes and traits contributing to compensatory growth were assessed. A module of co-expressed genes was identified as positively correlated with dry matter intake (r = 0.77, P = 0.01). Functional annotation of genes within this module revealed gene ontology terms including RNA splicing and cell division. Our results suggest that compensatory growth of hepatic tissue in cattle may be the consequence of the expression of genes involved in these biological processes. Additionally, hub genes in this module may represent potential biomarkers for the selection of cattle with enhanced compensatory growth potential.

Effects of dietary prebiotic Mito (MHF-Y) and starvation on the compensatory growth, survival, and hematological parameters in Common carp (Cyprinus carpio L, 1758)

Abstract: In order to study the effect of prebiotic Mito on compensatory growth following one week starvation in common carp, the fish (4.5 ± 0.05 g) were examined for 60 days in three treatments. A control fed with non-prebiotic diet with no starvation (T1), a 2 group starved for one week then fed 0.2% of prebiotic (T2) and 3 group received no prebiotic diet after one week starvation. The highest percent of weight gain and specific growth rate and condition factor were obtained in the control followed by T2 with significant differences (P<0.05). The lowest amount of food conversion ratio and the highest amount of protein efficiency ratio were recorded in T1, too. The mortality rate was zero in all treatments. The number of red blood cells showed insignificant differences between the control and the other groups (P> 0.05). Correspondence M Bahrekazemi, Department of Fisheries, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran (e-mail: bahr.kazemi@gmail.com). Hemoglobin and hematocrit values significantly differed between T1 and two other treatments. T2 contained the highest number of white blood cells and lymphocyte while the percent of basophil, eosinophil and monocyte did not differ between treatments significantly (P> 0.05). So, although the use of 0.2% prebiotic largely caused compensatory growth in carp but was not so sufficient that exceed those of the control group. However, the addition of prebiotic Mito significantly elevated hematological status of the fish.

A methodological review on the feed restriction and refeeding in sheep

Abstract: Feed restriction is becoming forceful nowadays owing to a shortage in green vegetation during off seasons. There are other incidences wherein the feed restriction is adopted during lean seasons and making the animals recouped thereafter. Feeding of those animals between the feed restriction and recoupment period is becoming a challenge for the livestock producers. The objective of this article is to bring the effects of feed restriction at variable levels and the rapid recovery made during re-alimentation process. The process of recoupment in body weight and other parameters after considerable period of feed restriction is called as compensatory growth. Compensatory growth is manifested by the ability of the animal to outgain their better counterparts when given good quality ad-libitum after a period of underfeeding. Compensatory growth is associated with an increased feed intake and increased efficiency of nutrient utilization and also with change in the body composition. The body maintenance energy requirements will be usually low during feed restriction and increases slowly to the new feeding regime that is practiced in re-alimentation. The digestibility of the nutrients will be affected and this will be higher during feed restriction as the feed is retained for more time in the rumen. Decreased maintenance cost increased feed intake and increased efficiency of growth and inherited genetic background along with the increased feedload have been assessed as the key mechanism in the phenomenon of compensatory growth. The visceral organs and liver in special is also affected by compensatory growth. It is concluded that feed restriction and re-alimentation has a considerable effect on serum biochemical parameters, carcass traits and growth performance, nutrient digestibility duly reducing the cost per kg gain and cost of production in sheep. A feed restriction upto 30% of the ad-libitum feeding can be taken up without affecting the performance of the animal.