Fast-growing transgenic common carp mounfing compensatory growth

Compensatory growth is a phase of accelerated growth apparent when favourable conditions are restored after a period of growth depression. To investigate if F-2 common 'all-fish' growth hormone gene transgenic common carp (Cyprinus carpio) could mount compensatory growth, a 9 week study at 29 degrees C was performed. The control group was fed to satiation twice a day throughout the experiment. The other two groups were deprived of feed for 1 or 2 weeks, respectively, and then fed to satiation during the re-feeding period. At the end of the experiment, the live masses of fish in the deprived groups were still significantly lower than those of the controls. During the re-feeding period, size-adjusted mean specific growth rates and mean feed intakes were significantly higher in the deprived fish than in the controls, indicating a partial compensatory growth response in these fish. No significant differences were found in food conversion efficiency between the deprived and control fish during re-feeding, suggesting that hyperphagia was the mechanism responsible for increased growth rates. The proximate composition of the deprived fish at the end of the experiment was similar to that of the control fish. This study is, to our knowledge, the first to report that fast-growing transgenic fish can achieve partial compensation of growth following starvation. (c) 2007 The Authors Journal compilation (c) 2007 The Fisheries Society of the British Isles.

Early ontogeny of Ancherythroculter nigrocauda and effects of delayed first feeding on larvae

Development of embryos and larvae in Ancherythroculter nigrocauda Yih et Woo (1964) and effects of delayed first feeding on larvae were observed after artificial fertilization. The fertilized eggs were incubated at an average temperature of 26.5 degrees C (range: 25.7-27) and the larvae reared at temperatures ranging from 21.8 to 28 degrees C. First cleavage was at 50 min, epiboly began at 7 h 5 min, heartbeat reached 72 per min at 24 h 40 min and hatching occurred at 43 h 15 min after insemination. Mean total length of newly hatched larvae was 4.04 +/- 0.03 mm (n = 15). A one-chambered gas bladder was observed at 70 h 50 min, two chambers occurred at 15 days, and scales appeared approximately 30 days after hatching. Larvae began to feed exogenously at day 4 post-hatch at an average temperature of 24 degrees C. Food deprivation resulted in a progressive atrophy of skeletal muscle fibres, deterioration of the larval digestive system and cessation of organ differentiation. Larval growth under food deprivation was significantly affected by the time of first exogenous feeding. Starved larvae began to shrink, with negative growth from day 6 post-hatch. The point of no return (PNR) was reached at day 11 after hatching. Mortality of starved larvae increased sharply from day 12 after hatching.

Partial compensatory growth in hybrid tilapia Oreochromis mossambicus x O-niloticus following food deprivation

The capacity of hybrid tilapia Oreochromis mossambicus x O. niloticus [23.2 +/- 0.2 g (mean +/- SE)] to show compensatory growth was assessed in an 8-week experiment. Fish were deprived of feed for 1, 2 and 4 weeks, and then fed to satiation for 4 weeks; fish fed to satiation during the experiment served as control. Water temperature gradually declined from 28.1 to 25.5 degrees C throughout the experiment. Specific growth rate (SGR) decreased with progressive food deprivation. At the end of deprivation, body weight was lower in the deprived fish than in the control. Fish deprived for 4 weeks exhibited lower contents of lipids and energy in whole body, and higher moisture content and ratio of protein to energy (P/E) than those of the control; they also consumed feed faster than the control when normal feeding was resumed. All deprived fish showed higher food intake (FI) than that of the control during re-alimentation; however, enhanced SGR was only observed in the fish deprived for 4 weeks. There were no significant differences in digestibility of protein and energy, food efficiency (FE) or energy retention efficiency between the control and deprived fish. At the end of re-alimentation, deprived fish failed to catch up in body weight with the control, while content of moisture, lipids and energy, and P/E in whole body of the deprived fish did not significantly differ from that of the control. The results of the experiment revealed that the hybrid tilapia reared in freshwater showed partial capacity for compensatory growth following food deprivation of 4 weeks, and that growth compensation was due mainly to increased FI, rather than to improved FE.

Effect of ration on the growth and energy budget of Chinese longsnout catfish, Leiocassis longirostris Gunther

The effect of ration on growth and energy budget of Chinese longsnout catfish was investigated in a growth trial. Fish of initial body weight of 6.5 g were fed at six ration levels (RLs): starvation, 0.8%, 1.6%, 2.4%, 3.2% of body weight per day, and apparent satiation for 8 weeks. Fish were weighed biweekly to adjust feed amount. The results showed that specific growth rate in wet weight, protein and energy increased logarithmically with increased RLs. The relationship of specific growth rate in wet weight (SGRw, % day(-1)) and RL (%) was a decelerating curve: SGRw=-0.62+3.10 Ln(RL+1). The energy budget equation at satiation was: 100 IE=12.94 FE+5.50(ZE+UE)+40.07 HE+41.49 RE, where IE, FE, (ZE+UE), HE, RE are food energy, faecal energy, excretory energy, heat production and recovered energy respectively. Body composition was slightly but significantly affected by ration size except for protein content. The most efficient ration based on the relationship between RL and feed efficiency ratio in energy (FERe) was 1.8% of body weight per day.

Factors affecting the efficiency of somatic cell nuclear transplantation in the fish embryo

Procedures to improve somatic cell nuclear transplantation in fish were evaluated. We reported effects of nonirradiated recipient eggs, inactivated recipient eggs, different combinations between recipient eggs and donor cells, duration of serum starvation, generation number, and passage number of donor cells on developmental rates of nuclear transplant (NT) embryos. Exposure to 25,000 R of gamma-rays inactivated recipient eggs. Single nucleus of cultured, synchronized somatic cell from gynogenetic bighead carp (Aristichthys nobilis) was transplanted into nonirradiated or genetically inactivated unfertilized egg of gibel carp (Carassius auratus gibelio). There was no significant difference in developmental rate between nonirradiated and inactivated recipient eggs (27.27% vs. 25.71%, respectively). Chromosome count showed that 70.59% of NT embryos contained 48 chromosomes. It showed that most NT embryos came from donor nuclei of bighead carp, which was supported by microsatellite analysis of NT embryos. But 23.53% of NT embryos contained more than 48 chromosomes. It was presumed that those superfluous chromosomes came from nonirradiated recipient eggs. Besides, 5.88% of NT embryos were chimeras. Eggs of blunt-snout bream (Megalobrama amblycephala) and gibel carp were better recipient eggs than those of loach (Misgurnus anguillicaudatus) (25% and 18.03% vs. 8.43%). Among different duration of serum starvation, developmental rate of NT embryos from somatic nuclei of three-day serum starvation was the highest, reaching 25.71% compared to 14.14% (control), 20% (five-day), and 21.95% (seven-day). Cultured donor cells of less passage facilitated reprogramming of NT embryos than those of more passage. Recloning might improve the developmental rate of NT embryos from the differentiated donor nuclei. Developmental rate of fourth generation was the highest (54.83%) and the lowest for first generation (14.14%) compared to second generation (38.96%) and third generation (53.01%). (C) 2002 Wiley-Liss, Inc.

Comparison of compensatory growth responses of juvenile three-spined stickleback and minnow following similar food deprivation protocols

The compensatory growth responses of individual juveniles of two co-existing species were compared after identical periods of starvation to determine inter-specific similarities and differences. The carnivorous stickleback Gasterosteus aculeatus was compared with the omnivorous minnow Phoxinus phoxinus. Both species experienced 1 or 2 weeks of starvation before being re-fed ad libitum. The two species differed in their response to the starvation periods, with minnows showing a lower weight-specific loss. Both species showed compensatory responses in appetite, growth and to a lesser extent, growth efficiency. Minnows wholly compensated for 1 and 2 weeks of starvation. At the end of the experiment, sticklebacks starved For 2 weeks were still showing a compensatory response and had nut achieved full compensation. The compensatory responses of the sticklebacks showed a lag of a week before developing in the re-feeding phase, whereas the response of the minnows was immediate. Analysis of lipid and dry matter concentrations suggested that the compensatory response restored reserve lipids while also bringing the fish back to the growth trajectory of continuously fed fish. (C) 2001 The Fisheries Society of the British Isles.

Spontaneous activity was unaffected by ration size in Nile tilapia and gibel carp

Two growth trials using a range of ration sizes from starvation to maximum feeding suggested that linear relationships existed between specific growth rate and ration size for Nile tilapia and givel carp, Continuous measurement of activity showed that activity level, in terms of distance swum per day, was not affected significantly by ration size in both Nile tilapia and gibel carp. (C) 2001 The Fisheries Society of the British Isles.

Energy budget of Nile tilapia (Oreochromis niloticus) in relation to ration size

Nile tilapia weighing 8.29-11.02 g were fed a practical diet at seven ration levels (starvation, 0.5, 1, 2, 3, 4% body weight per day and satiation) twice a day at 30 degrees C. Feed consumption, apparent digestibility, nitrogenous excretion and growth were determined directly, and heat production was calculated by difference of energy budget. The relationship between specific growth rate in wet weight (SGR(w), percentage per day) and ration size (RL, percentage per day) was a decelerating curve described as SGR(w) = 2.98 (1 - e(-0.61(RL-0.43))). The apparent digestibility coefficients for dry matter and protein showed a decreasing pattern with increasing ration while the apparent digestibility coefficient of energy was not significantly affected by ration size. The proportion of gross energy intake lost in nitrogenous excretion tended to decrease with increasing ration. Feed efficiency was highest, and the proportion of gross energy intake channelled to heat production was lowest, at an intermediate ration level (2% per day). The energy budget at the satiation level was: 100IE = 16.9FE + 1.2(ZE + UE) + 62.3HE + 19.6RE, where IE, FE, (ZE + UE), HE and RE represent gross energy intake, faecal energy, excretory (non-faecal) energy loss, heat production and recovered energy (growth), respectively. (C) 1997 Elsevier Science B.V.

Effect of ration and body size on the energy budget of juvenile white sturgeon

Growth and energy budget were measured for three sizes(2.4, 11.1 and 22.5 g) of juvenile white sturgeon Acipenser transmontanus held at 18.5 degrees C and fed tubificid worms at different levels ranging from starvation to ad libitum. For each size-class, specific growth rate increased linearly with increasing ration, and conversion efficiency was highest at the maximum ration. Growth rate decreased with increasing fish size at the maximum ration, but increased with size al each restricted ration. Conversion efficiency increased with increasing ration for each size-class and was usually highest at the maximum ration. Faecal production accounted for 3.2-5.2% of food energy. The proportion of food energy lost in nitrogenous excretion decreased with increasing ration. With increases in ration, the allocation of metabolizable energy to metabolism decreased, while that to growth increased. Fish size had no significant effect on the allocation of metabolizable energy to metabolism or growth. Al the maximum ration, on average 64.9% of metabolizable energy was spent on metabolism, and 35.1% on growth. (C) 1996 The Fisheries Society of the British Isles

EFFECT OF RATION SIZE ON THE GROWTH AND ENERGY BUDGET OF THE GRASS CARP, CTENOPHARYNGODON-IDELLA VAL

Young grass carp (12-13 g) were kept at five ration levels ranging from starvation to ad libitum feeding at 30-degrees-C. They were fed duckweed. Food consumption, absorption efficiency and growth were determined directly, and metabolism and nitrogenous excretion calculated indirectly from energy and nitrogen budgets, respectively. The relationship between specific growth rate and ration size was linear. Absorption efficiency for energy was not affected by ration size and averaged 50.6 +/- 0.57% (mean +/- s.e.). Depending on ration size, energy lost in excretion accounted for 4.5-5.9% of the food energy, energy channelled to metabolism accounted for 34.4-48.3% of the food energy, and energy retained as growth accounted for 6.7-11.9% of the food energy. Regardless of ration, a constant proportion of food energy (30.7%) was accounted for by feeding metabolism (total metabolism minus fasting metabolism). The energy budget at the maximum ration was: 100 C = 49.1F + 4.5U + 3.6R(fa) + 30.9R(fe) + 11.9G, where C, F, U, R(fa), R(fe) and G represent food consumption, faecal production, excretion, fasting metabolism, feeding metabolism and growth, respectively.

Microarray Analyses of Gene Expression during the Tetrahymena thermophila Life Cycle

Background: The model eukaryote, Tetrahymena thermophila, is the first ciliated protozoan whose genome has been sequenced, enabling genome-wide analysis of gene expression. Methodology/Principal Findings: A genome-wide microarray platform containing the predicted coding sequences (putative genes) for T. thermophila is described, validated and used to study gene expression during the three major stages of the organism's life cycle: growth, starvation and conjugation. Conclusions/Significance: Of the,27,000 predicted open reading frames, transcripts homologous to only,5900 are not detectable in any of these life cycle stages, indicating that this single-celled organism does indeed contain a large number of functional genes. Transcripts from over 5000 predicted genes are expressed at levels >5x corrected background and 95 genes are expressed at >250x corrected background in all stages. Transcripts homologous to 91 predicted genes are specifically expressed and 155 more are highly up-regulated in growing cells, while 90 are specifically expressed and 616 are up-regulated during starvation. Strikingly, transcripts homologous to 1068 predicted genes are specifically expressed and 1753 are significantly up-regulated during conjugation. The patterns of gene expression during conjugation correlate well with the developmental stages of meiosis, nuclear differentiation and DNA elimination. The relationship between gene expression and chromosome fragmentation is analyzed. Genes encoding proteins known to interact or to function in complexes show similar expression patterns, indicating that co-ordinate expression with putative genes of known function can identify genes with related functions. New candidate genes associated with the RNAi-like process of DNA elimination and with meiosis are identified and the late stages of conjugation are shown to be characterized by specific expression of an unexpectedly large and diverse number of genes not involved in nuclear functions.

评价水产动物生长性能的生理生化指标和分子生物学指标

以奥利亚罗非鱼(Oreochromis aureus)为实验对象，设计了3种不同的摄食类型，分别是鲜活饵料组、饥饿3周后饱食投喂组和人工饲料组。鲜活饵料组投喂冰冻赤子爱胜蚓，利用蚯蚓体内丰富的营养成分和活性物质，以期获得奥利亚罗非鱼良好的生长状况；饥饿后饱食组是指饥饿3周后，以人工饲料饱食投喂2周，用于研究饥饿与补偿生长获得快速生长时血液理化指标的变化情况；人工饲料组作为对照组。纯淡水条件下养殖，水温25±2℃。测定了奥利亚罗非鱼在3种摄食类型饲喂下某些血液生理生化指标变化的情况，并将指标变化情况与增重率做相关性分析，试图找出能够反映奥利亚罗非鱼生长性能的血液生理生化指标。 研究结果表明，奥利亚罗非鱼在饥饿3周后获得了补偿生长，补偿生长时的增重率和特定生长率显著高于人工饲料组(P<0.05)，高于鲜活饵料组，但差别不显著；相关性分析研究表明血清总蛋白、胆固醇、四碘甲状腺原氨酸（T4）与增重率极显著相关(P<0.01)，血红蛋白显著相关(P<0.05)，红细胞、白细胞、碱性磷酸酶高度相关(相关系数为0.580、0.551和0.557)，因此，建议血清总蛋白、胆固醇和血红蛋白可作为能够反映罗非鱼生长性能的新指标。 根据序列设计引物，PCR反应条件：变性温度：95 ℃，3 min；退火温度：57℃，20 sec；延伸温度：72℃，5 min，共36个循环，从牙鲆、黑鲪和鲈鱼中克隆出胰岛素样生长因子（IGF-Ⅰ）部分序列，首次证实了IGF-Ⅰ在3种海水鱼中的存在。 利用蛋氨酸与ZnSO4•7H2O，在pH 5.5、80℃下，反应1小时，采用蛋氨酸与硫酸锌2：1的配料比，合成出了产物蛋氨酸螯合锌，蛋氨酸螯合锌外观白色，粉状，室温下微溶于水，不溶于乙醇，并用原子吸收光谱法测定其含锌量为15%，螯合率为88.2%。

Feeding level-scaled retention efficiency, growth and energy partitioning of a marine detritivorous fish, redlip mullet (Liza haematocheila T. & S.)

The effects of feeding level on growth, retention efficiency, faeces production and energy partitioning of redlip mullet were studied. A practical diet was used and fed at six levels from starvation, 1%, 2%, 3%, 4% of body weight (BW) to satiation for 3 weeks. The temperature was kept at 24 +/- 1 degrees C. Reducing the feeding amount resulted in significantly lower weight gain, and retention efficiency was significantly affected by feeding levels and attained the maximum at maximum feeding intake. Feeding 2% BW was the minimum required for fish to maintain growth. Fish carcass composition under different feeding levels could be divided into three groups: (1) starvation and FL1; (2) FL2 and FL3 and (3) FL4 and satiation, with significant differences among the groups but no differences in the groups except that ash content remained at constant value. Body composition of fish of group 2 was close to initial fish. The thermal-unit coefficient was 0.0381 at satiation, and significantly increased with increasing feeding levels. In order to accurately estimate basal metabolism (HeE), another trial on the relationship between HeE (kJ) and BW (g) was carried out. An exponential curve as HeE=0.1255BW(0.8386) explained this relationship. Intake energy (IE) increased from 11.30 to 63.08 kJ per fish, matching with different feeding levels. Energy allocated to growth of IE decreased with reducing feeding amount. There was a linear relationship between metabolism energy and retention energy in percentage.

Effects of temperature and delayed initial feeding on the survival and growth of Japanese flounder larvae

The effects of the timing of initial feeding (0, 1, 2 3 and 4 days after yolk exhaustion) and temperature (15, 18 and 21degrees C) on the point-of-no-return (PNR), survival and growth of laboratory-reared Japanese flounder Paralichthys olivaceus larvae were studied under controlled conditions. The larvae reached PNR on 7(.)7, 5(.)2 and 4(.)2 days-post-hatching (dph) at 15, 18 and 2 V C, respectively. At each temperature, larval growth did not differ significantly among the delayed initial feedings 1 day before PNR but decreased significantly in larvae first fed after that. In the treatments where initial feeding was equally delayed, larvae grew significantly faster at 18 and 21degrees C than at 15degrees C. The larvae survived apparently better at 15 and 18degrees C than at 21degrees C when initial feeding was equally delayed. At each temperature, survival of the larvae first fed before PNR did not differ noticeably, while delayed initial feeding after that apparently reduced their survival. These results indicated that there existed a negatively temperature-dependent PNR in the Japanese flounder larvae. Survival and growth of the larvae strongly depended on temperature as well as the timing of initial feeding. High temperature accelerated the yolk exhaustion and growth of the larvae and thus reduced their starvation tolerance and survival. To avoid potential starvation mortality and obtain good growth, the Japanese flounder larvae must establish successful initial feeding within 2 days after yolk exhaustion at 15degrees C and within 1 day at both 18 and 21degrees C. (C) 2005 The Fisheries Society of the British Isles.

Application of rotifer Brachionus plicatilis in detecting the toxicity of harmful algae

The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.