Effect of Temperature and Feeding Regime on the Specific Growth Rate of Sockeye Salmon Fry (Oncorhynchus nerka), with a Consideration of Size Effect

1973 ◽  
Vol 30 (8) ◽  
pp. 1191-1194 ◽  
Author(s):  
J. E. Shelbourn ◽  
J. R. Brett ◽  
S. Shirahata

Specific growth rates were obtained for sockeye fry (Oncorhynchus nerka) acclimated to four temperatures and fed excess ration over a 36-day period, starting at an initial weight of 0.4 g. The rates were 2.2 (5 C), 5.1 (10 C), 6.5 (15 C), and 6.1 (20 C)% wet weight/day. Continuous feeding for 15 hr/day at 20 C produced a significantly greater growth rate than feeding to satiation three times daily (P < 0.05). The growth rates are compared to those obtained for larger sockeye, determined in earlier experiments.

2013 ◽  
Vol 10 (8) ◽  
pp. 5267-5280 ◽  
Author(s):  
F. H. Chang ◽  
E. C. Marquis ◽  
C. W. Chang ◽  
G. C. Gong ◽  
C. H. Hsieh

Abstract. Allometric scaling of body size versus growth rate and mortality has been suggested to be a universal macroecological pattern, as described by the metabolic theory of ecology (MTE). However, whether such scaling generally holds in natural assemblages remains debated. Here, we test the hypothesis that the size-specific growth rate and grazing mortality scale with the body size with an exponent of −1/4 after temperature correction, as MTE predicts. To do so, we couple a dilution experiment with the FlowCAM imaging system to obtain size-specific growth rates and grazing mortality of natural microphytoplankton assemblages in the East China Sea. This novel approach allows us to achieve highly resolved size-specific measurements that would be very difficult to obtain in traditional size-fractionated measurements using filters. Our results do not support the MTE prediction. On average, the size-specific growth rates and grazing mortality scale almost isometrically with body size (with scaling exponent ∼0.1). However, this finding contains high uncertainty, as the size-scaling exponent varies substantially among assemblages. The fact that size-scaling exponent varies among assemblages prompts us to further investigate how the variation of size-specific growth rate and grazing mortality can interact to determine the microphytoplankton size structure, described by normalized biomass size spectrum (NBSS), among assemblages. We test whether the variation of microphytoplankton NBSS slopes is determined by (1) differential grazing mortality of small versus large individuals, (2) differential growth rate of small versus large individuals, or (3) combinations of these scenarios. Our results indicate that the ratio of the grazing mortality of the large size category to that of the small size category best explains the variation of NBSS slopes across environments, suggesting that higher grazing mortality of large microphytoplankton may release the small phytoplankton from grazing, which in turn leads to a steeper NBSS slope. This study contributes to understanding the relative importance of bottom-up versus top-down control in shaping microphytoplankton size structure.


1998 ◽  
Vol 64 (11) ◽  
pp. 4226-4233 ◽  
Author(s):  
Pim Van Hoek ◽  
Johannes P. Van Dijken ◽  
Jack T. Pronk

ABSTRACT The specific growth rate is a key control parameter in the industrial production of baker’s yeast. Nevertheless, quantitative data describing its effect on fermentative capacity are not available from the literature. In this study, the effect of the specific growth rate on the physiology and fermentative capacity of an industrialSaccharomyces cerevisiae strain in aerobic, glucose-limited chemostat cultures was investigated. At specific growth rates (dilution rates, D) below 0.28 h−1, glucose metabolism was fully respiratory. Above this dilution rate, respirofermentative metabolism set in, with ethanol production rates of up to 14 mmol of ethanol · g of biomass−1 · h−1at D = 0.40 h−1. A substantial fermentative capacity (assayed offline as ethanol production rate under anaerobic conditions) was found in cultures in which no ethanol was detectable (D < 0.28 h−1). This fermentative capacity increased with increasing dilution rates, from 10.0 mmol of ethanol · g of dry yeast biomass−1 · h−1 at D= 0.025 h−1 to 20.5 mmol of ethanol · g of dry yeast biomass−1 · h−1 atD = 0.28 h−1. At even higher dilution rates, the fermentative capacity showed only a small further increase, up to 22.0 mmol of ethanol · g of dry yeast biomass−1 · h−1 at D= 0.40 h−1. The activities of all glycolytic enzymes, pyruvate decarboxylase, and alcohol dehydrogenase were determined in cell extracts. Only the in vitro activities of pyruvate decarboxylase and phosphofructokinase showed a clear positive correlation with fermentative capacity. These enzymes are interesting targets for overexpression in attempts to improve the fermentative capacity of aerobic cultures grown at low specific growth rates.


1981 ◽  
Vol 15 (4) ◽  
pp. 327-331 ◽  
Author(s):  
P. R. Boyle

Healthy, undamaged specimens survive well in recirculating aquarium seawater of about 36 parts per thousand salinity and pH 7·4, having 50 mg.l-1 nitrogen as nitrate, < 0·1 mg.l-1 nitrogen as nitrite, and < 0·1 mg.l-1 nitrogen as ammonia, and a mean annual temperature of 14-15°C, about 5°C above ambient. For maximal growth rates, the gross wet weight of live crabs required as food ranges up to 10% of the weight of the octopus. Weight-specific growth rates fall from 3-4% day-1 at 100-200 g bodyweight, to 1-1°5% day-1 at >500 g bodyweight. Survival of healthy, wild-caught animals, commonly 4-6 months and up to 8 months, is apparently limited more by endogenous factors concerned with sexual maturation and lifespan than by aquarium conditions. Eggs have been laid but it has not yet been possible to hatch and rear them.


Microbiology ◽  
2005 ◽  
Vol 151 (1) ◽  
pp. 135-143 ◽  
Author(s):  
Tiina M. Pakula ◽  
Katri Salonen ◽  
Jaana Uusitalo ◽  
Merja Penttilä

Trichoderma reesei was cultivated in chemostat cultures on lactose-containing medium. The cultures were characterized for growth, consumption of the carbon source and protein production. Secreted proteins were produced most efficiently at low specific growth rates, 0·022–0·033 h−1, the highest specific rate of total protein production being 4·1 mg g−1 h−1 at the specific growth rate 0·031 h−1. At low specific growth rates, up to 29 % of the proteins produced were extracellular, in comparison to only 6–8 % at high specific growth rates, 0·045–0·066 h−1. To analyse protein synthesis and secretion in more detail, metabolic labelling of proteins was applied to analyse production of the major secreted protein, cellobiohydrolase I (CBHI, Cel7A). Intracellular and extracellular labelled CBHI was quantified and analysed for pI isoforms in two-dimensional gels, and the synthesis and secretion rates of the molecule were determined. Both the specific rates of CBHI synthesis and secretion were highest at low specific growth rates, the optimum being at 0·031 h−1. However, at low specific growth rates the secretion rate/synthesis rate ratio was significantly lower than that at high specific growth rates, indicating that at low growth rates the capacity of cells to transport the protein becomes limiting. In accordance with the high level of protein production and limitation in the secretory capacity, the transcript levels of the unfolded protein response (UPR) target genes pdi1 and bip1 as well as the gene encoding the UPR transcription factor hac1 were induced.


1978 ◽  
Vol 24 (1) ◽  
pp. 28-30 ◽  
Author(s):  
Adrian P. Wills ◽  
E. C. S. Chan

When deprived of biotin, Arthrobacter globiformis 425 exhibits abnormal morphology (large, branched forms of variable size) and a retardation of its normal growth rate. In chemostat cultures, when cells were grown under glucose limitation, the morphology was normal (coccoids or rods) at specific growth rates between 0.05 and 0.125 h−1 (doubling times between 14 and 5.5 h, respectively) at 25 °C. The coccoid-to-rod morphogenesis occurs at a specific growth rate of 0.11 h−1. At the same specific growth rates and temperature, but under biotin limitation, abnormal morphology was observed.


2006 ◽  
Vol 54 (8) ◽  
pp. 155-162 ◽  
Author(s):  
Y. Mokhayeri ◽  
A. Nichols ◽  
S. Murthy ◽  
R. Riffat ◽  
P. Dold ◽  
...  

Facilities across North America are designing plants to meet stringent limits of technology (LOT) treatment for nitrogen removal (3–5 mg/L total effluent nitrogen). The anoxic capacity requirements for meeting LOT treatment are dependent on the growth rates of the denitrifying organisms. The Blue Plains Advanced Wastewater Treatment Plant (AWTP) is one of many facilities in the Chesapeake Bay region that is evaluating its ability to meet LOT treatment capability. The plant uses methanol as an external carbon source in a post-denitrification process. The process is very sensitive to denitrification in the winter. One approach to improve anoxic capacity utilization is to use an alternative substrate for denitrification in the winter to promote the growth of organisms that denitrify at higher rates. The aim of this study was to evaluate denitrification maximum specific growth rates for three substrates, acetate, corn syrup and methanol, at two temperatures (13 °C and 19 °C). These temperatures approximately reflect the minimum monthly and average annual wastewater temperature at the Blue Plains AWTP. The results suggest that the maximum specific growth rate (μmax) for corn syrup (1.3 d−1) and acetate (1.2 d−1) are higher than that for methanol (0.5 d−1) at low temperature of 13 °C. A similar trend was observed at 19 °C.


1995 ◽  
Vol 16 (3) ◽  
pp. 257-264 ◽  
Author(s):  
Carlos Frederico Duarte Rocha

AbstractThe growth of males and females of the tropidurid lizard Liolaemus lutzae was studied in the seasonal tropical habitat of the restinga da Barra de Maricá, Rio de Janeiro State, southeastern Brazil. Growth rates of lizards decreased with size in both sexes; the size specific growth rates of females were significantly lower than those of males. Adult males were larger than adult females. The data indicate that despite maturing at a larger size, males grow faster than females and mature at similar ages. There was a significant relationship between amount of rainfall and lizard growth rate in both sexes.


1975 ◽  
Vol 32 (11) ◽  
pp. 2103-2110 ◽  
Author(s):  
J. R. Brett ◽  
J. E. Shelbourn

The specific growth rate of young sockeye salmon (Oncorhynchus nerka) was studied for a period of 7 mo to determine the effect of body weight when on restricted and unrestricted rations. It was hypothesized that a restricted ration would result in a fixed growth rate until size became a limiting factor reducing food demand below the prescribed level and thereby reducing growth rate. The results support the hypothesis, with the possible exception that growth rate may increase slightly during the period of fixed ration. On excess ration the specific growth rate fell from 3.6% weight per day (2.4 g mean weight) to 1.0% weight per day (37 g mean weight); intermediate constant growth rates accompanied the periods of fixed ration, inflecting to lower rates subsequently. The general equation log G = a + b log W (where G = specific growth rate, and W = weight in grams) was found to apply to a number of salmonids. The slope value of b = −0.4 ±.04 appears to characterize the family, with the intercept a taking on different values according to the varying capacity for rapid growth.


Author(s):  
H. Barnes

Data are presented on the growth rate of Verruca stroemia under natural conditions and when exposed continuously and cleaned repeatedly. Several series exposed at different times of the year were followed.Rapid growth takes place (under raft conditions) following settlement; the maximum size is virtually reached in one season's growth between spring and early winter. There is little growth in midwinter.Differences between the mean specific growth rates of the various series can be ascribed to differences in the availability of food.The question is discussed as to whether there is any seasonal rhythm; the evidence indicates that no marked rhythmic pattern of growth exists.Observations on deep-water populations would be of value for comparison and to unmask any relatively weak rhythmic growth.The mean specific growth rates at half their maximum size are compared for several species—Balanus balanoides, B. crenatus, B. balanus, Chthamalus stellatus and Verruca stroemia; it is similar for all species except Chthamalus stellatus. The high level barnacle may require stimulation such as is provided by wave action to elicit full metabolic activity.


Microbiology ◽  
2004 ◽  
Vol 150 (5) ◽  
pp. 1413-1426 ◽  
Author(s):  
Robert A. Cox

Further understanding of the physiological states of Mycobacterium tuberculosis and other mycobacteria was sought through comparisons with the genomic properties and macromolecular compositions of Streptomyces coelicolor A3(2), grown at 30 °C, and Escherichia coli B/r, grown at 37 °C. A frame of reference was established based on quantitative relationships observed between specific growth rates (μ) of cells and their macromolecular compositions. The concept of a schematic cell based on transcription/translation coupling, average genes and average proteins was developed to provide an instantaneous view of macromolecular synthesis carried out by cells growing at their maximum rate. It was inferred that the ultra-fast growth of E. coli results from its ability to increase the average number of rRNA (rrn) operons per cell through polyploidy, thereby increasing its capacity for ribosome synthesis. The maximum growth rate of E. coli was deduced to be limited by the rate of uptake and consumption of nutrients providing energy. Three characteristic properties of S. coelicolor A3(2) growing optimally (μ=0·30 h−1) were identified. First, the rate of DNA replication was found to approach the rate reported for E. coli (μ=1·73 h−1); secondly, all rrn operons were calculated to be fully engaged in precursor-rRNA synthesis; thirdly, compared with E. coli, protein synthesis was found to depend on higher concentrations of ribosomes and lower concentrations of aminoacyl-tRNA and EF-Tu. An equation was derived for E. coli B/r relating μ to the number of rrn operons per genome. Values of μ=0·69 h−1 and μ=1·00 h−1 were obtained respectively for cells with one or two rrn operons per genome. Using the author's equation relating the number of rrn operons per genome to maximum growth rate, it is expected that M. tuberculosis with one rrn operon should be capable of growing much faster than it actually does. Therefore, it is suggested that the high number of insertion sequences in this species attenuates growth rate to still lower values.


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