Growth Depression Research Articles

Mid‐ to Late Holocene climate transition and moisture dynamics inferred from South Swedish tree‐ring data

ABSTRACTA 1561‐year tree‐ring width (TRW) chronology covering the period 2668–1108 BC (4617–3057 BP) has been developed from 159 moisture‐sensitive peatland pines (Pinus sylvestris L.) sampled at Åbuamossen, southern Sweden. Tree population dynamics and annual growth responses of the trees were shown to reflect and give absolute age to regional hydro‐climatological changes. The main wet‐shifts recorded in the TRW data were precisely dated to 2150–2100, 1550 and 1230–1150 BC (4100–4050, 3500 and 3180–3000 BP) and are likely to be related to the stepwise Mid‐ to Late Holocene climate transition, during which the condition changed from relatively warm and dry towards cold and moist in the northern hemisphere. The tree‐colonization phase was ended by several long‐lasting periods showing depressed annual tree growth and an abrupt dying‐off phase, possibly caused by increasing water level in the peatland as well as the adjacent river Helge Å. This study demonstrates that TRW data obtained from subfossil peatland trees can provide detailed information and exact age control on moisture variability in peatlands associated with regional hydroclimatic changes. Moreover, the combined information from the stratigraphical and the TRW analyses enabled a detailed temporal and spatial site development reconstruction.

Metabolic Investigation in Gluconacetobacter xylinus and Its Bacterial Cellulose Production under a Direct Current Electric Field.

The effects of a direct current (DC) electric field on the growth and metabolism of Gluconacetobacter xylinus were investigated in static culture. When a DC electric field at 10 mA was applied using platinum electrodes to the culture broth, bacterial cellulose (BC) production was promoted in 12 h but was inhibited in the last 12 h as compared to the control (without DC electric field). At the cathode, the presence of the hydrogen generated a strong reductive environment that is beneficial to cell growth. As compared to the control, the activities of glycolysis and tricarboxylic acid cycle, as well as BC productivity were observed to be slightly higher in the first 12 h. However, due to the absence of sufficient oxygen, lactic acid was accumulated from pyruvic acid at 18 h, which was not in favor of BC production. At the anode, DC inhibited cell growth in 6 h when compared to the control. The metabolic activity in G. xylinus was inhibited through the suppression of the tricarboxylic acid cycle and glycolysis. At 18–24 h, cell density was observed to decrease, which might be due to the electrolysis of water that significantly dropped the pH of cultural broth far beyond the optimal range. Meanwhile, metabolites for self-protection were accumulated, for instance proline, glutamic acid, gluconic acid, and fatty acids. Notably, the accumulation of gluconic acid and lactic acid made it a really tough acid stress to cells at the anode and finally led to depression of cell growth.

Unexpected capacity for organic carbon assimilation by Thermosynechococcus elongatus, a crucial photosynthetic model organism

Genetic modification of key residues of photosystems is essential to identify functionally crucial processes by spectroscopic and crystallographic investigation; the required protein stability favours use of thermophilic species. The currently unique thermophilic photosynthetic model organism is the cyanobacterial genus Thermosynechococcus. We report the ability of Thermosynechococcus elongatus to assimilate organic carbon, specifically D-fructose. Growth in the presence of a photosynthesis inhibitor opens the door towards crucial amino acid substitutions in photosystems by the rescue of otherwise lethal mutations. Yet depression of batch-culture growth after 7 days implies that additional developments are needed.

Effect of inbreeding and individual increase in inbreeding on growth in Nilagiri and Sandyno breeds of sheep

SummaryIndividual increase in inbreeding coefficients (ΔFi) has been recommended as an alternate measure of inbreeding. It can account for the differences in pedigree knowledge of individual animals and avoids overestimation due to increased number of known generations. The effect of inbreeding (F) and equivalent inbreeding (EF) calculated fromΔFi, on growth traits were studied in Nilagiri and Sandyno flocks of sheep. The study was based on data maintained at the Sheep Breeding Research Station, Sandynallah. The pedigree information and equivalent number of generations were less in Sandyno compared with Nilagiri sheep. The average F and EF for the Nilagiri population were 2.17 and 2.44, respectively and the corresponding values for Sandyno sheep were 0.83 and 0.84, respectively. The trend of inbreeding over years in both the populations indicated that EF was higher during earlier generations when pedigree information was shallow. Among the significant effects of inbreeding, the depression in growth per 1 percent increase in inbreeding ranged from 0.04 kg in weaning weight to 0.10 kg in yearling weight. In general, more traits were affected by inbreeding in Nilagiri sheep, in which greater regression of growth traits was noticed with F compared with EF. Higher values of EF than F in earlier generations in both the populations indicate that EF avoided the potential overestimation of inbreeding coefficient during recent generations. In the Sandyno population, the magnitude of depression noticed among growth traits with significant effects of inbreeding was higher. The differences in response to F and EF noticed in the two populations and possible causes for the trait wise differences in response to F and EF are appropriately discussed.

Relationships among maxillofacial morphologies, bone properties, and bone metabolic markers in patients with jaw deformities

The aim of this study was to determine the relationships among bone properties, bone metabolic markers, and types of jaw deformity. The subjects were 55 female patients with jaw deformities. Skeletal morphology was examined using lateral cephalograms, and the patients were divided into three groups according to the type of anteroposterior skeletal pattern. Serum osteocalcin, bone alkaline phosphatase, and tartrate-resistant acid phosphatase isoform 5b, as well as deoxypyridinoline in urine, were measured as bone metabolic markers. Quantitative ultrasound (QUS) measurements were used to assess bone properties at the calcaneal bone. The bone volume and bone density of the condylar process were measured in 43 patients by computed tomography. There were no significant differences in bone metabolic markers and QUS parameters between the groups, although bone formation and resorption markers tended to be higher in patients with a protrusive mandible. On the other hand, patients with mandibular retrusion had a higher tendency to have small and dense condylar processes. In conclusion, the results suggest that growth depression or a degenerative change in the mandibular condyle is involved in the pathogenesis of mandibular retrusion, although risk factors for progressive condylar resorption were not determined.

Responses of heat shock protein 70 and caspase-3/7 to dietary selenomethionine in juvenile white sturgeon.

An 8-week feeding trial was conducted to investigate the responses of juvenile white sturgeon (Acipenser transmontanus) to elevated dietary selenium (Se) based on the determination of the RNA/DNA ratio in muscle, heat shock protein 70 (Hsp70), and caspase-3/7 in muscle and/or liver tissues. Four semi-purified test diets were prepared by adding different levels of L-selenomethionine (0, 50, 100, and 200 mg/kg diet). The analytical determinations of total Se were 2.2, 19.7, 40.1, and 77.7 mg/kg diet. The sturgeon (initial body weight: 30 ± 2 g; mean ± SEM) were raised in indoor tanks provided with flow through freshwater (18–19 °C). There were three replicates for each dietary treatment with 25 fish per replicate. The liver and muscle tissues were collected at 4 and 8 weeks after feeding the test diets. A significant interaction between duration and levels of dietary Se exposures on RNA/DNA ratio in the muscle tissue was detected (P < 0.05). Although there was no significant main effect due to the duration of dietary Se exposures (i.e., 4 weeks versus 8 weeks) on muscle RNA/DNA ratio (P ≥ 0.05), the ratio was significantly decreased with increasing dietary Se levels. Significant main effects were caused by the duration and levels of dietary Se exposures on Hsp70 in both the muscle and liver tissues, with significant increases in Hsp70 due to a longer exposure (8 weeks) and higher levels (40.1 and 77.7 mg Se/kg diet) of dietary Se. The caspase-3/7 activity in the liver were significantly higher in fish fed the diets containing 40.1 and 77.7 mg Se/kg diet than those fed the other diets. The toxic thresholds of Se in the muscle were estimated to be 32.2 and 26.6 mg Se/kg for the depressed specific growth rate and the induced Hsp70 response in muscle, respectively. This result indicated that the Hsp70 response in muscle is a more sensitive biomarker than the SGR of sturgeon for evaluating Se toxicity in white sturgeon. Results of the current study suggest that a mechanism involved with the activation of stress protein production and apoptosis protects white sturgeon from the lethal effect of Se.

The role of psychological representations in kidney transplantation. The reliability and validity of the Hungarian version of Transplanted Organ Questionnaire

According to interdisciplinary research the transplanted organ representations play an important role in successful transplantation. The aim of the study was to assess the reliability and validity of the Hungarian version of Transplanted Organ Questionnaire in kidney transplant recipients. 151 patients were assessed using the Spielberger Anxiety Inventory, the Beck Depression Inventory, the Posttraumatic Growth Inventory and the Transplanted Organ Questionnaire. Serum creatinine levels from routine clinical blood tests were collected. The scale showed good internal consistency (Cronbach-alpha = 0.89; 0.87; 0.80), and the test-retest reliability was excellent. The Transplanted Organ Questionnaire scores moderately correlated with depression, anxiety and posttraumatic growth. The "Psychological rejection" scale correlated with higher serum creatinine level (p = 0.001, t = 5.17). The reliability and validity of the Hungarian version of Transplanted Organ Questionnaire in the studied sample were excellent. The questionnaire is a useful psychometric tool in the exploration of transplant patients' representations about the donor and the organ.

Oral antibody to interleukin-10 reduces growth rate depression due to Eimeria spp. infection in broiler chickens

Eimeria spp. must be controlled in floor-reared poultry to prevent the onset of coccidiosis. Here we use an oral antibody to chicken IL-10 to prevent growth depression due to Eimeria spp. infection. Egg antibody directed against an antigenic peptide of IL-10 was produced in laying hens and measured using an ELISA. In the first experiment, egg yolk powder containing antibody to chicken IL-10 (vlpramqt conjugate) (anti-IL-10 yolk powder) was fed at 3.4 g/kg feed to determine growth response following mixed Eimeria spp. challenge. Chicks were fed either anti-IL-10 antibodies or control antibodies and challenged (d3) with either sterile saline or a 10× attenuated Eimeria spp. vaccine. Control-fed and Eimeria-challenged chicks grew 8.8% slower than those challenged with saline (P < 0.04), whereas anti-IL-10-fed Eimeria challenged chicks were not different from untreated controls. In the second trial a dose response was performed with doses of either 0 (control antibody), 0.34-, or 3.4-g anti-IL-10 yolk powder/kg feed. Control-fed, Eimeria-challenged chicks grew 10.6% slower than control saline-challenged chicks (P < 0.05); however, anti-IL-10-fed chicks fed either dose of anti-IL-10 were not different from saline-challenged chicks. Finally, the effect of anti-IL-10 on acquired immunity was investigated. Chicks were fed control or anti-IL-10 yolk powder and vaccinated with a 1× dose of Eimeria vaccine at d 3. After 14 d, antibody was removed from the diet. Chicks were either saline or 10× Eimeria challenged at d 17. We found that the anti-IL-10-fed chickens did not show a reduction in growth due to challenge; hence anti-IL-10 does not appear to affect adaptive immunity during the primary immunization. Overall, use of an antibody to IL-10 is a novel method in preventing adverse effects of Eimeria spp. infection in poultry.

Effects of dietary genistein on GH/IGF-I axis of Nile tilapia Oreochromis niloticus

There is considerable concern that isoflavones, such as genistein in fish feed composed of soybean protein, aff ects somatic growth in fish. Our previous works demonstrated that 30 and 300 μg/g dietary genistein had no significant eff ect on growth performance in Nile tilapia (Oreochromis niloticus), but the higher level of genistein (3 000 μg/g) significantly depressed growth. This study was conducted to further examine the eff ects of dietary genistein on the endocrine disruption on growth hormone/insulin-like growth factor-I (GH/IGF-I) axis in Nile tilapia (O. niloticus). Juvenile fish were fed by hand twice daily to satiation with one of four isonitrogenous and isoenergetic diets, each containing either 0, 30, 300 or 3 000 μg/g genistein. Following an 8-week feeding period, plasma GH and IGF-I levels were investigated by radioimmunoassay and gene expression levels of gh, ghrelin, gnrhs, ghr, npy, npyrs, pacap, ghrs, igf-I, igf-Ir, and igfbp3 were examined by real-time PCR. The results show that no significant change in plasma GH and IGF-I levels in fish fed with diets containing 30 μg/g and 300 μg/g genistein. mRNA expression of genes along the GH/IGF-I axis remained unaff ected, except for igf-Ir, which was stimulated by the 300 μg/g genistein diet. While in fish fed the 3 000 μg/g genistein diet, the plasma GH and IGF-I levels decreased, and mRNA expression of gh, ghr2, npyr1, igf-I, and igf-Ir were also significantly depressed. In contrast, npy and igfbp3 mRNA expression were enhanced. This study provides convincing evidence for growth impediment by genistein by disturbing the GH/IGF-I axis in Nile tilapia O. niloticus.

Dendritic cell based immunotherapy using tumor stem cells mediates potent antitumor immune responses

Cancer stem cells (CSCs) are demonstrated to be usually less sensitive to conventional methods of cancer therapies, resulting in tumor relapse. It is well-known that an ideal treatment would be able to selectively target and kill CSCs, so as to avoid the tumor reversion. The aim of our present study was to evaluate the effectiveness of a dendritic cell (DC) based vaccine against CSCs in a mouse model of malignant melanoma. C57BL/6 mouse bone marrow derived DCs pulsed with a murine melanoma cell line (B16F10) or CSC lysates were used as a vaccine. Immunization of mice with CSC lysate-pulsed DCs was able to induce a significant prophylactic effect by a higher increase in lifespan and obvious depression of tumor growth in tumor bearing mice. The mice vaccinated with DCs loaded with CSC-lysate were revealed to produce specific cytotoxic responses to CSCs. The proliferation assay and cytokine (IFN-γ and IL-4) secretion of mice vaccinated with CSC lysate-pulsed DCs also showed more favorable results, when compared to those receiving B16F10 lysate-pulsed DCs. These findings suggest a potential strategy to improve the efficacy of DC-based immunotherapy of cancers.

Growth Performance and Feed Utilization of Clarias gariepinus (Teugels) Fed Different Dietary Levels of Soaked Bauhinia Monandra (Kutz) Seed Meal

This study was conducted to evaluate the suitability of soaked &lt;em&gt;Bauhinia monandra&lt;/em&gt; (Kutz) seed as alternative protein source for &lt;em&gt;Clarias gariepinus&lt;/em&gt; and to determine cost of feed compounded. The proximate analysis of the diet (crude protein, crude fibre, ash, moisture content and lipid) were determined using AOAC (1980). Data for each parameter was subjected to one way analysis of variance (ANOVA) while means of various results were compared at 5% level of significance. A preliminary study was conducted to determine the best processing method that reduced anti-nutrients to the minimum level without impairing nutrients composition. Boiled, toasted and soaked seeds were used. &lt;em&gt;Bauhinia&lt;/em&gt; seeds soaked for 96 hours had least concentration of anti-nutrients. The experimental diets was formulated to contain soaked &lt;em&gt;Bauhinia&lt;/em&gt; seed meal (SBSM) at levels of 25%, 50% and 75% inclusion (Diets 2, 3 and 4 respectively) with two diets acting as control (Diets 1 and 5). All diets were isonitrogenous (40% crude protein) and isocaloric (3212kcal/kg). A 12 weeks feeding trial was conducted using juveniles which were randomly distributed into 12 improvised non-recirculatory and semi-flow through indoor plastic tanks (52cm X 34cm X 33.5cm) at a stocking rate of 10 fish per tank and three (3) replicates per treatment. The experimental design was complete randomized. The fish were fed at 5% body weight, twice daily. Diets with higher inclusion levels of SBSM (diets 3 and 4) significantly depressed growth performance of fish. The variations observed in the Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Feed Efficiency Ratio (FER) and Protein Efficiency Ratio (PER) were associated with the anti-nutrients present in the diets, these parameters reduced with increasing levels of SBSM in the diets of fish. Based on the relative cost of diets per unit weight gain and protein gain, diet 2 (25% SBSM) was most economical. The results suggested that SBSM can be used to substitute up to 25% levels of dietary protein in &lt;em&gt;C. gariepinus&lt;/em&gt; juveniles without significant reduction in growth.

Effects of Dietary Methionine Levels on Choline Requirements of Starter White Pekin Ducks.

A 2×5 factorial experiment, using 2 dietary methionine levels (0.28% and 0.48%) and 5 dietary choline levels (0, 394, 823, 1,239, and 1,743 mg/kg), was conducted to study the effects of dietary methionine status on choline requirements of starter white Pekin ducks from 7 to 28 days of age. Four hundred eighty 7-d-old male White Pekin ducks were randomly allotted to ten dietary treatments, each containing 6 replicate pens with 8 birds per pen. At 28 d of age, weight gain, feed intake, and feed/gain were measured and the legs of all ducks from each pen were examined for incidence of perosis. Perosis and growth depression were observed in choline-deficient ducks and supplementation of choline reduced perosis and significantly increased weight gain and feed intake regardless of dietary methionine levels (p<0.05). In addition, significant positive effects of dietary methionine supplementation on weight gain, feed intake, and feed/gain were observed at any choline level (p<0.05). Supplementation of 1,743 mg/kg choline in diets alleviated the depression of weight gain and feed intake caused by methionine deficiency at 0.28% methionine level. The interaction between choline and methionine influenced weight gain and feed intake of ducks (p<0.05). At 0.28% methionine level, 1,743 mg/kg choline group caused 4.92% and 3.23% amount of improvement in weight gain and feed intake compared with 1,239 mg/kg choline group, respectively. According to the broken-line regression, the choline requirements of starter Pekin ducks for weight gain and feed intake were 1,472 and 1,424 mg/kg at 0.28% methionine level and 946 and 907 mg/kg at 0.48% methionine level, respectively. It suggested the choline recommendations of starter Pekin ducks on a semi-purified diet were 1448 mg/kg at 0.28% methionine level and 927 mg/kg at 0.48% methionine level, respectively. Compared with the adequate methionine level, menthionine deficiency markedly increased the choline requirements of ducks.

Yeast β-d-glucans induced antimicrobial peptide expressions against Salmonella infection in broiler chickens

The present study was designed to investigate the effects of yeast β-d-glucans (YG) on gene expression of endogenous β-defensins (AvBDs), cathelicidins (Cath) and liver-expressed antimicrobial peptide-2 (LEAP-2) in broilers challenged with Salmonella enteritidis (SE). 240 day-old Cobb male broilers were randomly assigned to 2×2 factorial arrangements of treatments with two levels of dietary YG (0 or 200mg/kg in diet) and two levels of SE challenge (0 or 1×109 SE at 7–9 days of age). The results showed SE infection reduced growth performance,and increased salmonella cecal colonization and internal organs invasion, increased concentration of intestinal specific IgA and serum specific IgG antibody, as compared to uninfected birds. SE challenge differentially regulated AvBDs, Caths and LEAP-2 gene expression in the jejunum and spleen of broiler chickens during the infection period. However, YG supplementation inhibited the growth depression by SE challenge, and further increased level of serum specific IgG and intestinal specific IgA antibody. Higher level of salmonella colonization and internal organs invasion in the SE-infected birds were reduced by YG. SE-induced differentially expression patterns of AMPs genes was inhibited or changed by YG. Results indicated YG enhance chicken's resistance to salmonella infection.

潜砂制限がアサリの成長に及ぼす影響

In Hakodate Bay, Hokkaido, the short-necked clam Ruditapes philippinarum shows highly depressed growth rate above 30 mm in shell length. In this area, clams often burrow into the sediment at an angle, which seems to be caused by boulders in the sediment. For benthic bivalves, burrowing into sediment is an important behavior to escape severe environmental conditions and predation. To examine possible effects of boulders on burrowing behavior and growth of the clam, we compared burrowing depth of the clams in contact with boulders and those clear of boulders. The ratio of burrowing depth to shell length was higher in those clear of boulders than those touching boulders. To understand this depressed growth mechanism, we carried out a field growth experiment and a laboratory feeding experiment. In the field experiment, we compared the shell growth increments of clams with restricted burrowing into sediment and those of unrestricted burrowing for three months. Shell growth increments of the clams with restricted burrowing were smaller regardless of their initial shell sizes. In the laboratory experiment, we compared the clearance rates of clams under six different situations: predatory crabs were present or not and burrowing treatments were unrestricted (deep sediment), restricted (shallow sediment) or impossible (i.e., no sediment). Both the presence of predators and restriction of burrowing decreased the clearance rate of clams; however their interaction was not significant. These results suggest boulders in the sediment restrict burrowing, and then depress shell growth of the clams. Sediment features must be taken into account for fishery analysis and stock recovery potential in clams with burrowing behavior.

Balancing the budget: can the Swiss debt brake end endless U.S. deficits?

The United States is the world’s leading issuer of treasury bonds, and according to current forecasts there is no end in sight to annual budget deficits. Evidence strongly suggests that persistent deficits are closely associated with depressed growth, raising the possibility that a permanent end to U.S. deficits would permanently increase the country’s economic growth. However, with nearly a half-century long, almost unbroken line of deficits it is unlikely that Congress will rise to the occasion and end borrowing on its own. Suggesting that the United States needs budget-balancing regulations, possibly at the constitutional level, this paper explores two types of balanced-budget measures: deficit-elimination and debt-capping.

A Vitamin on the Mind: New Discoveries on Control of the Brain by Vitamin A.

Vitamin A is essential for many physiological processes and is particularly crucial during early life, when vitamin A deficiency increases mortality through elevated rates of infection. This deadly aspect of vitamin A deficiency masks other effects that, while not lethal, may nevertheless cause significant issues if vitamin A insufficiency reoccurs during later childhood or in the adult. One such effect is on the brain. Vitamin A is essential for several regions of the brain, and this chapter focuses on two regions: the hippocampus, needed for learning and memory, and the hypothalamus, necessary to maintain the body's internal physiological balance. Vitamin A, through its active metabolite retinoic acid, is required to support neuroplasticity in the hippocampus, and vitamin A deficiency has a dramatic effect on depressing learning and memory. The effects of vitamin A deficiency on the hypothalamus may lead to depression of appetite and growth. Much of this research has relied on animal studies, and it will be essential in the future to determine the full role of vitamin A in the human brain.

Effects of Graded Dietary L-arginine Supply on Organ Growth in Four Genetically Diverse Layer Lines during Rearing Period.

Little information has been available about the influence of genetic background and dietary L-arginine (Arg) supply on organ growth of chickens. Therefore, the present study examined the effects of a graded ad libitum Arg supply providing 70, 100 and 200% of recommended Arg concentration on organ growth of female chickens from hatch to 18 weeks of age. The chickens derived from four layer lines of different phylogeny (white vs. brown) and laying performance (high vs. low). Based on residual feed and absolute body and organ weights recorded in six-week-intervals, feed consumption, changes of relative organ weights and allometric organ growth were compared between experimental groups.Surplus Arg caused higher feed intake than insufficient Arg (p<0.01) that induced growth depression in turn (p <0.05). During the entire trial chicken's heart, gizzard and liver decreased relatively to their body growth (p<0.001) and showed strong positive correlations among each other. On the contrary, proportions of pancreas and lymphoid organs increased until week 12 (p<0.001) and correlated positively among each other. Due to their opposite growth behaviour (p<0.001), internal organs were assigned to two separate groups. Furthermore, insufficient Arg induced larger proportions of bursa, gizzard and liver compared with a higher Arg supply (p<0.05). In contrast to less Arg containing diets, surplus Arg decreased relative spleen weights (p<0.01). The overall allometric evaluation of data indicated a precocious development of heart, liver, gizzard, pancreas and bursa independent of chicken's genetic and nutritional background. However, insufficient Arg retarded the maturation of spleen and thymus compared with an adequate Arg supply.In conclusion, the present results emphasised the essential function of Arg in layer performance, and indicated different sensitivities of internal organs rather to chicken's dietary Arg supply than to their genetic background.

Evaluation of Stocking All Female Largemouth Bass (&amp;lt;i&amp;gt;Micropterus salmoides&amp;lt;/i&amp;gt;) in Alabama (USA) Ponds

Excessive largemouth bass ( Micropterus salmoides ) recruitment in small impoundments leads to density-dependent growth depression, causing populations to have length distributions skewed towards smaller fish. To address this issue, we conducted three trials that evaluated stocking all female largemouth bass (F-LMB) in two small Alabama ponds (0.5 and 2.0 ha) where the drainage basin was isolated. Age-1 fish were individually identified for sex using a micro pipette inserted in the urogenital pore, tagged, and stocked at 38-40 F-LMB/ha into ponds that contained pre-established sunfish ( Lepomis spp.) populations. Female largemouth bass were collected with electrofishing, angling, and rotenone over a 2.5- to 5-year period among the three trials. Sex was correctly identified for 179 of the 180 F-LMB stocked. One male was detected in the first trial which resulted in successful largemouth bass reproduction and this trial was terminated after two years. Growth was rapid the first 2 years after stocking as 3-year-old fish reached an average of 429 to 459 mm and 1.37 to 1.66 kg in all 3 trials. However, 2 years after stocking, growth was nil in the second trial even though relative weights of F-LMB were generally greater than 100. In this second trial, removal of about 30% of the F-LMB inhabiting the pond and stocking small Nile tilapia Oreochromis niloticus (25 - 75 mm) resulted in average weights increasing from 1.30 to 2.34 kg in 1 year. Growth of F-LMB continued in the third trail, and average size approached 500 mm and 2.2 kg three years after stocking. Annual survival rates of F-LMB were high and ranged from 0.78 to 0.93 among the 3 trials. Stocking F-LMB offers an attractive alternative in ponds to create a low density largemouth bass population that displays fast growth and high survival when catch-and-release fishing is primarily practiced.

Compensating for a bad start: compensatory growth across life stages in an organism with a complex life cycle

Organisms with a complex life cycle are characterized by a life-history shift through metamorphosis and include organisms such as insects and amphibians. They must optimize their use of resources and behaviour across different life stages to maximize their fitness. An interesting question with regard to such life-history shifts is whether growth in the juvenile stage can be compensated for in the adult stage. Here we ask whether emerald damselflies (Lestes sponsa (Hansemann, 1823)) are able to compensate for depressed growth during the juvenile aquatic stage in their terrestrial adult stage. Lestes sponsa emerge at a fixed adult body size, but feed during the adult stage and are thus able to gain mass as adults. We performed a mark–recapture study to answer whether individuals that emerge from metamorphosis with a low mass are able to compensate by subsequent mass gain during the adult stage. Results showed that compensatory mass gain occurred in the adult stage such that small individuals gained more mass than large individuals. We also found that females gained more mass than males. However, individuals that emerged at a low mass still had lower mass as mature adults than individuals that emerged at a high mass, suggesting that compensation was not complete. This suggests that larval ecology and adult fitness are tightly linked and future research should focus more on elucidating the nature of this relationship.

349: Maternal depression, stress, and fetal growth

349: Maternal depression, stress, and fetal growth