Showing papers on "Compensatory growth (organism) published in 2010"

Juvenile compensatory growth has negative consequences for reproduction in Trinidadian guppies (Poecilia reticulata)

Abstract: Compensatory or 'catch-up' growth may be an adaptive mechanism that buffers the growth trajectory of young organisms from deviations caused by reduced food availability. Theory generally assumes that rapid juvenile compensatory growth impacts reproduction only through its positive effects on age and size at maturation, but potential reproductive costs to juvenile compensatory growth remain virtually unexplored. We used a food manipulation experiment to examine the reproductive consequences of compensatory growth in Trinidadian guppies (Poecilia reticulata). Compensatory growth did not affect adult growth rates, litter production rates or investment in offspring size. However, compensatory growth had negative effects on litter size, independent of the effects of female body length, resulting in a 20% decline in offspring production. We discuss potential mechanisms behind this observed cost to reproduction.

Physiological mechanisms underlying a trade-off between growth rate and tolerance of feed deprivation in the European sea bass ( Dicentrarchus labrax )

Abstract: The specific growth rate (SGR) of a cohort of 2000 tagged juvenile European sea bass was measured in a common tank, during two sequential cycles comprising three-weeks feed deprivation followed by three-weeks ad libitum re-feeding. After correction for initial size at age as fork length, there was a direct correlation between negative SGR (rate of mass loss) during feed deprivation and positive SGR (rate of compensatory growth) during re-feeding (Spearman rank correlation R=0.388, P=0.000002). Following a period of rearing under standard culture conditions, individuals representing 'high growth' phenotypes (GP) and 'high tolerance of feed deprivation' phenotypes (DP) were selected from either end of the SGR spectrum. Static and swimming respirometry could not demonstrate lower routine or standard metabolic rate in DP to account for greater tolerance of feed deprivation. Increased rates of compensatory growth in GP were not linked to greater maximum metabolic rate, aerobic metabolic scope or maximum cardiac performance than DP. When fed a standard ration, however, GP completed the specific dynamic action (SDA) response significantly faster than DP. Therefore, higher growth rate in GP was linked to greater capacity to process food. There was no difference in SDA coefficient, an indicator of energetic efficiency. The results indicate that individual variation in growth rate in sea bass reflects, in part, a trade-off against tolerance of food deprivation. The two phenotypes represented the opposing ends of a spectrum. The GP aims to exploit available resources and grow as rapidly as possible but at a cost of physiological and/or behavioural attributes, which lead to increased energy dissipation when food is not available. An opposing strategy, exemplified by DP, is less 'boom and bust', with a lower physiological capacity to exploit resources but which is less costly to sustain during periods of food deprivation.

Enhanced mitochondrial complex gene function and reduced liver size may mediate improved feed efficiency of beef cattle during compensatory growth

Abstract: Growing ruminants under extended dietary restriction exhibit compensatory growth upon ad libitum feeding, which is associated with increased feed efficiency, lower basal energy requirements, and changes in circulating concentrations of metabolic hormones. To identify mechanisms contributing to these physiological changes, 8-month-old steers were fed either ad libitum (control; n = 6) or 60–70% of intake of control animals (feed-restricted; n = 6) for a period of 12 weeks. All steers were fed ad libitum for the remaining 8 weeks of experimentation (realimentation). Liver was biopsied at days −14, +1, and +14 relative to realimentation for gene expression analysis by microarray hybridization. During early realimentation, feed-restricted steers exhibited greater rates of gain and feed efficiency than controls and an increase in expression of genes functioning in cellular metabolism, cholesterol biosynthesis, oxidative phosphorylation, glycolysis, and gluconeogenesis. Gene expression changes during feed restriction were similar to those reported in mice, indicating similar effects of caloric restriction across species. Based on expression of genes involved in cell division and growth and upregulation of genes encoding mitochondrial complex proteins in early realimentation, it was concluded that reduced hepatic size and increased mitochondrial function may contribute to improved feed efficiency observed during compensatory growth.

Stressful Dieting: Nutritional Conditions but Not Compensatory Growth Elevate Corticosterone Levels in Zebra Finch Nestlings and Fledglings

Abstract: Unfavourable conditions throughout the period of parental care can severely affect growth, reproductive performance, and survival. Yet, individuals may be affected differently, depending on the developmental period during which constraints are experienced. Here we tested whether the nestling phase compared to the fledgling phase is more susceptible to nutritional stress by considering biometry, physiology, sexually selected male ornaments and survival using zebra finches (Taeniopygia guttata) as a model species. As nestlings (day 0–17) or fledglings (day 17–35), subjects were raised either on low or high quality food. A low quality diet resulted in significantly elevated baseline corticosterone titres in both nestlings and fledglings. Subjects showed substantial compensatory growth after they had experienced low quality food as nestlings but catch-up growth did neither lead to elevated baseline corticosterone titres nor did we detect long term effects on biometry, male cheek patch, or survival. The compensation for temporally unfavourable environmental conditions reflects substantial phenotypic plasticity and the results show that costs of catch-up growth were not mediated via corticosterone as a physiological correlate of allostatic load. These findings provide new insights into the mechanisms and plasticity with which animals respond to periods of constraints during development as they may occur in a mistiming of breeding.

Interactive effects of clipping and nutrient availability on the compensatory growth of a grass species

Abstract: Resource availability is an important factor affecting the capacity of compensatory growth after grazing. We performed a greenhouse experiment with Poa bulbosa, a small perennial grass of the Mediterranean and Central Asian grasslands, to test the importance of nutrient availability for compensatory growth after clipping. We also compared the results with predictions of the limited resource model (LRM). Plants were grown at low and high fertilization levels and subjected to a clipping treatment. Contrary to the LMR, we found that in Poa plants compensatory growth occurred under the high fertilization level, while it did not occur under the low level. The LMR predicts a higher tolerance for grazing in the stressful environment. Our plants showed a significant decrease in their relative growth rates (RGR) after clipping. Although the plants allocated a 32–188% greater fraction of the mass to lamina growth after clipping, this greater allocation to the leaves did not fully compensate for the initial reduction in leaf area ratio (LAR). A sensitivity analysis showed for the clipped plants under the high fertilization treatment, that changes in leaf allocation (flam) enabled the plants to compensate for a part of the potential loss caused by defoliation. Probably, the increased biomass allocation comes largely from the bulbs. We conclude that the inconsistency of the LRM with our results originates in the lack of compensatory mechanisms in the model. To better understand how environmental conditions affect tolerance to herbivory, the effects of compensatory growth should be taken into account.

Compensatory growth responses in juvenile fat snook, Centropomus parallelus Poey, following food deprivation

Abstract: The compensatory growth in juvenile fat snook (13.7 g) was evaluated in fish subjected to four treatments: continuously fed (control); subjected to 1 (D1), 2 (D2) and 3 (D3) weeks of food deprivation, followed by a 5-week re-feeding period. At the end of food deprivation, the body weights at the different treatments were significantly different and inversely related to the length of the food deprivation period (C=16.425 g; D1=14.024 g; D2=13.542 g; D3=12.228 g). During re-feeding, no differences were observed in the slopes of body weight growth curves among treatments, indicating failure in full growth compensation. In the first re-feeding week (week 4), although hyperphagia was observed for all re-fed groups, better food conversion ratios were detected only for D1 and D2, reflected in an enhancement in the specific growth rates. From week 5 onwards, no differences between treatments and control were detected for any variable. The total food intake was lower for D2 and D3 compared with the control. In the present study, fish showed partial compensatory growth when subjected to a maximum of 2 weeks of food deprivation. Therefore, the food deprivation can promote production losses, even considering a reduction in the total food intake.

Weak compensatory growth makes short-term starvation an unsuitable technique to mitigate body deformities of Tinca tinca juveniles in intensive culture

Abstract: Juvenile tench, Tinca tinca (L.) (initial mean weight 0.67 g) were continuously fed at high (5.0% of fish biomass) or low (2.5% of fish biomass) daily doses of a commercial formulated diet, or starved for 6 days, then fed these doses. The experiment lasted 40 days. Visible skeletal deformities occurred in fish fed the high doses, and the 6-day food deprivation mitigated the percentage of deformed fish from 37.3 to 12.1%. Deformities were associated with higher condition coefficient value. Faster growing individuals were more susceptible to body malformations within the feeding groups. No compensatory growth in body weight was observed in juveniles fed high or low doses. Lack of compensation was supported by lower carbon/nitrogen ratio in starved-re-alimented fish. Morphometric indices (condition coefficient and height/length ratio) suggested only partial compensation observed mostly during the first few days after the end of starvation. The possible mechanisms underlying this weak compensatory response in T. tinca juveniles may be associated with their slow growth rate and low oxygen consumption. Short starvation mitigates body deformities in intensively fed tench juveniles, however, this technique is not recommended in aquaculture due to their weak compensatory growth response.

Compensatory growth of a submerged macrophyte (Vallisneria spiralis) in response to partial leaf removal: effects of sediment nutrient levels

Abstract: Many plants mitigate damage due to loss of tissues through compensatory growth, yet their compensatory abilities vary depending on physical and environmental conditions. We conducted an outdoor experiment using a 2 × 2 factorial experimental design (leaf damage and nutrient level), in order to evaluate the compensatory growth response of Vallisneria spiralis (a submerged macrophyte widely distributed in China) to partial leaf removal in two nutrient regimes. Our results reveal that under both high- and low-nutrient conditions, V. spiralis exhibited substantial compensatory growth response to partial leaf removal via accelerated growth rates, with significantly greater compensatory abilities observed in the high-nutrient sediments. These observations suggest that V. spiralis has a strong compensatory ability to partial leaf removal, providing arguably one of the major mechanisms for the coexistence of this plant with herbivores, in particular, in eutrophic freshwater ecosystems (e.g. Lake Taihu).

Developing world perspective: the importance of growth for short-term health.

Abstract: Recently, concern has been raised about the potential adverse long-term consequences of rapid child growth. Rapid early childhood weight gain is associated with increased likelihood of being overweight or obese later in childhood and of having risk factors for the development of chronic disease such insulin resistance and elevated blood pressure. This has led to concerns about the wisdom of promoting catch-up growth in infants born small for gestational age or in children with poor growth after birth. In considering the costs and benefits of promoting catch-up growth, we must not lose sight of the immediate health threats to children in resource-poor environments in developing countries where child morbidity and mortality remain high. The literature on short-term consequences of growth is limited by its focus on attained size as an indicator of prior nutritional status, but generally shows that children with evidence of poor prior growth are at greater risk of morbidity and mortality from common infectious diseases, including lower respiratory infections and diarrhea. In these settings, failure to promote compensatory growth may have devastating short-term consequences.

Compensatory growth responses to defoliation and light availability in two native Mexican woody plant species

Abstract: Defoliation, often caused by herbivory, is a common cause of biomass loss for plants that can affect current and future growth and reproduction. There are three models that predict contrasting compensatory growth responses of plants to herbivory and resource availability: (1) Growth rate model, (2) Compensatory continuum hypothesis and (3) Limiting resource model. The predictions of these three models were tested on the tree Brosimum alicastrum and the liana Vitis tiliifolia. Seedlings were subjected to three levels of experimental defoliation (0%, 50% and 90% leaf removal) along a light resource gradient (1%, 9% and 65% of full sun). In both species, defoliation significantly increased leaf production rate and relative growth rate of leaf area, but not of biomass. Net assimilation rate was the strongest driver of biomass growth in both species, but leaf area ratio and specific leaf area were also important in B. alicastrum.CompensatoryresponsesofleafareagrowthinB.alicastrumweresignificantlygreaterinhigherthanlower light availability, consistent with the compensatory continuum hypothesis predictions, but in contrast to the growth rate model predictions. The limiting resource model offered an explanation for all possible experimental outcomes by directly considering the effects of environmental differences in resource availability. Resumen: La defoliaci´ on ocasionada por herbivorcausa pde biomasa que puede afectar el crecimiento y la reproducci´ on en plantas. Tres modelos que predicen respuestas contrastantes del crecimiento compensatorio de

Collagen content and architecture of the pectoralis muscle in male chicks and broilers reared under various nutritional conditions

Abstract: Varying chicken growth rates were induced with different nutritional regimes, and the collagen content and architecture of M pectoralis (PT) were compared among 21-day-old chicks and broilers at 80 or 95 days of age The percentage of muscle weight to live weight was higher in rapid growing chicks (84%) than slow growing chicks (63%) The 80-day-old broilers engaged in compensatory growth after the early slow growth period producing PT muscle at 11% of live weight The 80- and 95-day-old chicks with restricted late growth after an early rapid growth period showed PT weight at 8% and 9% of live weight, respectively Collagen content of the PT muscle markedly decreased from the chicks to the broilers The collagen concentration was higher in the late-growth restricted broilers (167-188 mg/g) than the compensatory growth broilers (101-110 mg/g) Collagen concentration did not differ between the rapid and slow growing chicks (272 and 294 mg/g) Scanning electron micrographs showed thick and thin perimysia, and honeycomb endomysia In the perimysia, a stack layer of collagen platelets and a reticular layer of collagen fiber cords were distinguished and collagen baskets of adipocytes were observed The perimysial collagen fibers became thicker during growth of the chicks to broilers However, in the late-growth restricted broilers, the perimysial collagen fibers seemed to have retarded development compared with the compensatory growth birds The PT muscle of chickens develops optimally when body growth is enhanced The PT muscle of the compensatory growth broilers had improved collagen architecture regardless of the marked decrease in collagen content

Grazing tolerance of biennial meadow plants in relation to resource availability

Abstract: In this thesis I studied responses of three biennial, monocarpic plants Erysimum strictum, Gentianella amarella, and G. campestris, to various aspects in resource availability (i.e. competition, mineral nutrition, neighbor removal) and environmental stress (early frost) at adult or rosette stages and how these effects are related to grazing tolerance. I also studied how manipulations in resource availability affected arbuscular mycorrhizal colonization of the roots. All three species were relatively tolerant to simulated grazing and in most cases plants were able to compensate quite well for minor biomass losses. According to the compensatory continuum hypothesis, tolerance is most pronounced in resource-rich conditions, but this was not always the case in the present experiments. Erysimum strictum compensated for defoliation at the rosette stage but the reproductive output of adult plants was reduced markedly in the next year. This reduction was strongest among fertilized plants. Moreover, apex removal at the adult stage resulted in overcompensation (i.e. clipped plants were more productive) but only in the absence of fertilization and in the presence of competition, which is against the compensatory continuum hypothesis. In E. strictum a potential cost of compensation appeared as delayed flowering and fruit maturation among clipped plants. However, in spite of early frost treatment clipped plants were still able to overcompensate. In Gentianella amarella and G. campestris, apex removal reduced growth and reproductive performance in most cases. Effects on root fungal parameters were positive or neutral. This pattern suggests that simulated above-ground herbivory tends to increase carbon limitation, and therefore regrowing shoots and the fungal symbionts may appear as alternative, competing sinks for the limited carbon reserves of the host plant. Both shoot architecture and resource availability modify the responses of the study plants to apical damage at both rosette and adult stages. In addition, different environmental stress factors affect success in compensatory growth.

Effect of ration size restriction on compensatory growth and proximate composition of dark-banded rockfish, Sebastes inermis.

Abstract: Compensatory growth and chemical composition of dark-banded rockfish (mean weight: 13.6 g) were examined after fish had experienced five different pre-feeding regimes. Fish were fed at 0% (R0), 25% (R25), 50% (R50), 75% (R75) and 100% (control) satiation for 2 wk before satiation feeding for 5 wk. Fish of R75 and R50 achieved the same body weight as the control fish after satiation feeding for 2 and 5 wk, respectively. Although the specific growth rate and feed efficiency of R25 and R0 fish were higher than those of the control fish during the first 3 wk of satiation feeding, they did not caught up with the body weight of the control fish. At the Week 2 and Week 7, the ratios lipid to lean body mass of R50, R25 and R0 fish were significantly lower than those of control fish, and there was no difference between the control and R75 fish. This result suggests that the fish subjected to a proper pre-restricted feeding (50-75% satiation) for 2 wk result in complete compensatory growth, while the fish experienced more severe feed restriction (0-25% satiation) show a partial compensatory growth capacity.

Aspectos fundamentales del crecimiento en ovinos

Abstract: The animal growth is a complex process regulated and affected by several factors. Aspects such as age, genetics, the physiological stage, the nutritional status, calving type, among others, effect the sheep growth. Recent advances in this field have achieved a better understanding of regulation of growth, but without clarifying several points. The compensatory growth is used as a management strategy for profit in animal productions and it is also used in sheep. The objective of this review was to gather information on key concepts of the sheep growth physiology to provide a better understanding of the mechanisms involved in this process.

Effect of growth trajectories on adult performance and lifespan in three-spined sticklebacks

Abstract: Changes in environmental conditions in early life can cause changes in the tempo and pattern of growth and development in animals. Natural selection favours processes that enable animals to make decisions that maximise Darwinian fitness. These decisions are influenced by trade-offs between current and future benefits. An episode of poor conditions (i.e. reduced nutrition, low temperature and changes in photoperiod) is generally linked to a slowing of growth. If adequate conditions are restored after this episode, growth rate is accelerated and normal adult size can be reached; in other words, ‘compensatory’ growth occurs. Compensatory growth has benefits in enabling a return to the typical size-at-age growth trajectory. Although this ability to alter growth rate provides a degree of adaptability, there is now increasing evidence that resource allocation to rapid growth carries various long-term costs. While there is experimental evidence that poor environmental conditions in early life can induce subsequent compensatory growth, little is known about the long-term effects of compensatory growth on locomotor and reproductive performance, and on lifespan. In this thesis, I investigated how different growth trajectories affected subsequent performance (i.e. locomotory capability, reproduction and lifespan), and how any such effects were influenced by the perceived time until the key life history event of reproduction. Using juvenile three-spined sticklebacks (Gasterosteus aculeatus), I showed that temperature manipulations early in life in three temperature treatments (low, intermediate and high, independent of food supply) or food restriction (with a constant temperature) affected skeletal growth trajectory not only during the manipulation itself, but also during a subsequent compensatory phase. To investigate the effects of time of year, all experimental groups of temperature and food manipulations were replicated at different seasonal periods (= Winter or Spring); to manipulate apparent time of year while holding initial size and maturity constant, a photoperiod manipulation was also undertaken at both seasonal times (ambient or delayed photoperiod). While there was compensatory growth (i.e. accelerated growth) in the food manipulation, temperature manipulations induced both positive compensatory growth (i.e. growth acceleration following exposure to low temperature) and also ‘negative’ compensatory growth (decelerated growth following exposure to high temperature). The outcome of these changes was that fish in all treatment groups reached the same average size by sexual maturity, despite having different growth patterns. However, early growth trajectories influenced both pre-breeding swimming endurance and its decline over the course of the breeding season, such that swimming ability was negatively correlated with compensatory growth whereas ‘negative’ compensatory growth reduced swimming ability less (Chapter 2). Reproductive investment (males: sexual ornaments and ability to build nests; females: first clutch size and mean egg size) was negatively affected by compensatory growth; positive effects of ‘negative’ compensatory growth on reproduction were found (Chapter 3). Interestingly, the effects of growth rate on subsequent swimming and reproductive performance were greater when the perceived, or actual, time until the breeding season was shorter (Chapter 2 and 3). These results implied that increased metabolic rates and cellular damage (e.g. oxidative stress) induced by compensatory growth negatively affected subsequent performance, while decelerated growth reduced the damage levels and so later performance was less affected. Under food manipulation, there were similar patterns: compensatory growth (i.e. accelerated growth) negatively affected locomotor and reproductive performance and the time until the breeding season altered the effects on performance (Chapter 4). To further examine trade-offs between growth rate and fitness parameters such as future reproductive investment and rates of senescence, I developed four theoretical models of increasing complexity with different growth-damage scenarios, ranging from assuming that the animal maximises growth regardless of any costs, through assuming a relationship between growth rate and mortality risk, to assuming growth leads to damage accumulation and that the animal is able to apportion resources between somatic growth, gonadal growth and investment in repair of damage. The models predicted that growth trajectories strongly influenced future reproductive investment irrespective of body size at the time of breeding, presumably due to the effects of damage accumulation in the run up to the breeding season; the predictions of the most complex model were closest to the experimental data on egg production (Chapter 5). Lifespan was different among treatment groups and also influenced by early growth trajectories. Compensatory growth negatively affected lifespan whereas ‘negative’ compensatory growth extended lifespan. Lifespan in female sticklebacks was positively related to egg production. Male sticklebacks lived for a shorter time when they showed less growth between their first and second breeding seasons, and a greater change in the duration of having a red throat between the first and second breeding season (an indicator of reproductive senescence). The costs of compensation were strongest when the perceived time until breeding was shortest (Chapter 6). Consequently, this thesis shows that environment conditions in early life have substantial effects on subsequent performances and lifespan. Moreover, results in this thesis strongly support the time-stress hypothesis, that is the time available until the onset of a key life history event, in this case reproduction, influences outcomes.

Compensatory growth of Carex scabrirostris in different habitats in alpine meadow

Abstract: Aims Compensatory growth is affected by defoliation ratio,water and soil nutrient availability,but it is unclear which factor is most important in the overcompensatory response to herbivores in a particular area.Our objectives were to examine how compensatory growth of Carex scabrirostris varies with different habitats in an alpine Kobresia humilis meadow and determine relative effects of these factors on compensatory growth.Methods Our field experiment at the Haibei Research Station of the Chinese Academy of Sciences from April to September 2007 included three habitats (habitat I:pen pasture,grazed × high nutrient availability;habitat Ⅱ:pass pasture,grazed × low nutrient availability and habitat Ⅲ:ungrazed pasture,null defoliation ratio × low nutrient availability) with three plots per habitat.In each plot,12 quadrats (0.5 m × 0.5 m) were divided into two groups:6 caged and 6 uncaged.For each of these sets of 6 quadrats,3 quadrats were sampled in mid-June and 3 in mid-August.We used canonical correspondence analysis (CCA) with potential impact factors selected by the forward selection procedure for the compensatory growth of C.scabrirostris ramets to determine the relative effects of defoliation ratio,water and soil nutrient variables on compensatory growth.Important findings The compensatory increase in dry weight,cover,density and height of ramets were higher for the habitat Ⅰ than for habitats Ⅱ and Ⅲ.Overcompensation of aboveground biomass per ramet occurred in habitat Ⅰ and Ⅱ,whereas undercompensation was found in habitat Ⅲ.The biomass allocation to growth function per ramet in habitat Ⅰ was equal to that of Ⅲ but higher than that of Ⅱ.Storage allocation was greatest in habitat Ⅱ,moderate in Ⅲ,and least in Ⅰ.Storage allocation was negatively correlated with growth and clonal propagation allocations,and growth allocation was negatively correlated with sexual reproductive allocation.The most important factors that induced compensatory growth were relative growth rate and soil organic matter content in June,followed by nitrogen content in August and defoliation ratio.These results suggest that the ramets in nutrient-rich habitat or in nutrient-poor habitat but having a high storage allocation tend to have overcompensation growth.The nutrient-rich habitat can compensate for the negative effects of herbivores and improve the ability to tolerate herbivores.

The Growth and Energy Allocation of the Brown Flounder,Paralichthys Olivaceus During Thermal Manipulation

Abstract: An experiment was conducted to investigate the growth and energy allocation of juvenile brown flounder,Paralichthys olivaceus during thermal manipulationDuring the stress period,the 175 ℃ acclimated juvenile brown flounder were cultured at 85 ℃(T85),130 ℃(T130),175 ℃(T175),220 ℃(T220),and 265 ℃(T265) for 10 dAt the end of the stress period,the fish in T220were larger than the other treatments in wet mass,dry mass,protein,and energy content,and except for dry mass,were not significantly different from those in T175 and T265The temperature induced growth differences were completely compensated in 30 d after the temperatures were adjusted to 220 ℃Through the stress period,less feed ingestion and a smaller fraction of energy allocated to growth mainly depressed the growth of fish at low temperatures(T85 and T130),whereas a smaller fraction of energy allocated to growth accounted for the slow growth in T175and T265When the fish was kept at low temperature,the energy lost in feces and respiration decreased the energy allocated to growthWhereas it was the higher proportion of excretion energy that caused less energy being allocated to growth for fish kept at high temperatureDuring the second 10 d period after temperature adjusting,fish in T85,T130,T175,and T265 ingested more feed than T220But no significant difference in ingestion was observed for the whole period after temperature adjusting and the energy allocations among growth,feces,excretion,and respiration show no treatment specific differenceHence it was concluded that compensatory growth was achieved mainly by short-term increaes in feed intake(hyperphagia)For the whole period after temperature adjusting,the daily unit body weight energy ingestion and growth in T85,T130,T175,and T265were significantly higher than in T220Thus the fish exhibited compensatory growthThrough the whole experimental period,fish in T85 ingested less feed than in the other treatmentsBut they allocated more energy to growth than the other treatments because they lost less energy in excretion and respirationDifferent temperature experiencing changed the protein and energy content of juvenile brown flounder and the energy content of fish in T85 and T265 were still significantly different from those in T220The above results indicated that juvenile brown flounder show flexibility to temperature changes and short-term temperature change would not impact their long-term growth

Viewing Plant Systematics through a Lens of Plant Compensatory Growth

Abstract: Plant compensatory growth is a phenomenon of exaggerated vegetative growth that occurs in plants as a result of mechanical damage (e.g., cutting or browsing). Because shoots, leaves, and other plant parts grow larger on plants undergoing compensation, they typically fall outside of the normal ranges given in plant identification keys and confuse students who are attempting to classify them. Here, we describe the conundrum faced by students collecting compensatory materials and offer suggestions on how to help students identify their “plant-in-hand” and how to seize a teaching moment to examine and explain the underlying processes that lead to this fascinating plant response.

Effects of Dietary Nutrient Composition on Compensatory Growth of Grower Olive Flounder Paralichthys olivaceus under Different Feeding Regimes at Suboptimal Temperature

Abstract: The effects of dietary nutrient composition on compensatory growth of grower olive flounder (Paralichthys olivaceus) under different feeding regimes at suboptimal temperature were determined. Four hundred five fish weighing 271.2 g were distributed into 27 300 L flow-through tanks (15 fish per tank). Nine treatments were prepared in triplicate: fish were hand-fed with control (C) diet for 12 weeks (12WF-C); four groups of fish were starved for 1 week and then fed C, high-protein (HP), high-lipid (HL), or combined high-protein and high-lipid (HPL) diets for 11 weeks; these groups are referred to as 11WF-C, 11WF-HP, 11WF-HL, and 11WF-HPL, respectively. Four other groups of fish were starved for 2 weeks and then fed C, HP, HL, and HPL diets for 10 weeks; these groups are referred to as 10WF-C, 10WF-HP, 10WF-HL, and 10WF-HPL, respectively. Weight gain and specific growth rate of fish from 12WF-C group were greater than those of fish from 11WF-C, 11WF-HP, 11WF-HL, 10WF-C, 10WFHP, and 10WF-HL groups, but not different from those of fish from 11WF-HPL and 10WF-HPL groups. Feed-efficiency ratio of fish from 12WF-C, 11WF-HP, 11WF-HPL, 10WF-HL, and 10WF-HPL groups was higher than that of fish in 11WF-C, 11WF-HL, 10WF-C, and 10WF-HP groups. The results of this study demonstrated that grower olive flounder subjected to 1- or 2-week feed deprivation were able to achieve full compensatory growth at suboptimal temperature only when fed HPL diet.

Effect of grazing disturbance and nutrient availability on the compensatory responses of community in alpine meadows

Abstract: A field experiment was conducted to study the compensatory growth and species diversity of community under different grazing intensities,nutrient availabilities and water contents of the soil.The results showed that the species richness index R and the species diversity index H' in pass habitat and ungrazed habitat was higher than that in pen habitat.The number of species was the lowest in pen habitat,which was only 54%of that in pass.The aboveground biomass showed overcompensation at the both pass and pen habitats,the belowground biomass showed exact compensation at the pen habitat and overcompensation at the pass habitat.In the pen habitat,the Elymus nutans and Kobresia humilis made a most important contribution to the aboveground overcompensation and the belowground fullcompensation,respectively.In pass pasture,Kobresia humilis made a most important contribution to the above and belowground overcompensation. The relative growth rate of the above and the belowground biomass did not differ among habitats, the water contents of the soil was not correlated with the above and belowground compensation,only the aboveground compensation was positively related to the defoliation rate and the total nitrogen content of the soil.These results supported the intermediate disturbance hypothesis and suggesteded that the compensatory pattern in community level was directly correlated with the compensatory varieties in species level; the compensatory growth of alpine meadows was mainly affected by the grazing intensity and the resource availability,especially the nitrogen nutrition and the impact of soil moisture was relatively small.

Compensatory growth responses in juvenile fat snook, Centropomus parallelus Poey, following food deprivation

Abstract: The compensatorygrowth in juvenile fat snook (13.7 g) was evaluated in ¢sh subjected to four treatments: continuously fed (control); subjected to 1 (D1), 2 (D2) and 3 (D3) weeks of food deprivation, followed by a 5-week re-feeding period. At the end of food deprivation, the body weights at the diierent treatments were signi¢cantly diierent and inversely related to the length of the food deprivation period (C516.425 g; D1514.024 g; D2513.542 g; D3512.228 g). During re-feeding, no diierences were observed in the slopes of bodyweight growth curves among treatments, indicating failure in full growth compensation. In the ¢rst re-feeding week (week 4), although hyperphagia was observed for all re-fed groups, better food conversion ratios were detected only for D1 and D2, re£ected in an enhancement in the speci¢c growth rates. From week 5 onwards, no diierences between treatments and control were detected for any variable. The total food intake was lower for D2 and D3 compared with the control. In the present study, ¢sh showed partial compensatory growth when subjected to a maximum of 2 weeks of food deprivation. Therefore, the food deprivation can promote production losses, even considering a reduction in the total food intake.

Compensatory growth of a submerged macrophyte (Vallisneria spiralis) in response to partial leaf removal: effects of sediment nutrient levels

Abstract: Many plants mitigate damage due to loss of tissues through compensatory growth, yet their compensatory abilities vary depending on physical and environmental conditions. We conducted an outdoor experiment using a 2 9 2 factorial experi- mental design (leaf damage and nutrient level), in order to evaluate the compensatory growth response of Vallisneria spiralis (a submerged macrophyte widely distributed in China) to partial leaf removal in two nutrient regimes. Our results reveal that under both high- and low-nutrient conditions, V. spiralis exhibited substantial compensatory growth response to partial leaf removal via accelerated growth rates, with significantly greater compensatory abilities observed in the high-nutrient sediments. These obser- vations suggest that V. spiralis has a strong compen- satory ability to partial leaf removal, providing arguably one of the major mechanisms for the coexistence of this plant with herbivores, in particular, in eutrophic freshwater ecosystems (e.g. Lake Taihu).