Is diel dualism in feeding activity influenced by competition between individuals?

1997 ◽  
Vol 75 (5) ◽  
pp. 661-669 ◽  
Author(s):  
Eva Brännäs ◽  
Anders Alanärä
Keyword(s):  
Growth Rate ◽  
Feeding Activity ◽  
The Self ◽  
Pit Tag ◽  
Ecological Benefits ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Group Members ◽  
Competition For Food ◽  
Leaving Groups ◽  
Specific Part

The feeding activity of eight groups of 15 rainbow trout (Oncorhynchus mykiss) each was recorded using self-feeders combined with passive integrated transponder (PIT) tag registrations. The diel pattern for all individuals was established by analysing the PIT-tag registrations. Most trout released the self-feeders during daylight, but in all groups some individuals (1–5) were active mainly during the night. The hypothesis that dualism in diel feeding activity is influenced by competition for food resources between individuals was then tested. In the first round, the diurnally active group members were removed, leaving groups with only 5 mainly nocturnally active individuals. After 3 weeks, the nocturnal individuals still released the self-feeders mainly in darkness. In a second round, the nocturnal individuals were removed, leaving the diurnal ones to self-feed in smaller groups. Again, no switch in activity occurred, but the diurnal trout continued to release the triggers in daylight. When food was available at all hours, individual fish seemed to gain little by releasing the demand feeders during a specific part of the light–dark cycle. The diurnal individuals were significantly (p < 0.05) larger than the nocturnal ones in the first round, but there were no significant (p > 0.05) differences in specific growth rate between the two categories. During the second round, there was no difference in mass between nocturnal and diurnal individuals, whereas the former had a significantly (p < 0.05) higher growth rate. The ecological benefits of dualism in feeding activity within groups of fish are discussed.

Hybridization with Domesticated Rainbow Trout (Oncorhynchus mykiss) Reduces Seasonal Variation in Growth of Steelhead Trout (O. mykiss)

1993 ◽  
Vol 50 (3) ◽  
pp. 480-487 ◽  
Author(s):  
Jörgen I. Johnsson ◽  
W. Craig Clarke ◽  
Ruth E. Withler
Keyword(s):  
Growth Rate ◽  
Seasonal Variation ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Natural Waters ◽  
Salt Water ◽  
Feeding Activity ◽  
Steelhead Trout ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Winter Conditions

We tested the hypothesis that hybridization with domesticated rainbow trout (Oncorhynchus mykiss) reduces the seasonal variation in growth in both fresh and salt water in anadromous steelhead trout (O. mykiss). The seasonal variation in freshwater growth was more pronounced in the steelhead trout than in the hybrid and domesticated trout. Consequently, differences in growth rate among groups were considerably higher during winter than in fall or spring. We suggest that high feeding activity during unfavourable winter conditions in natural waters is maladaptive, but is not selected against in protected hatchery environments with a continuous food supply. This may lead to genetic divergence in feeding physiology and/or behaviour between steelhead trout and domesticated rainbow trout. Growth rates in experimental groups transferred to seawater in December relative to groups transferred in April were faster in rainbow and hybrid trout than in steelhead trout. The results support the hypothesis that seasonal variation in seawater growth in steelhead trout is reduced by crossing with domesticated rainbow trout.

scholarly journals PROYEKSI STOKASTIK PRODUKSI PADI DI INDONESIA

2019 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Agnesya Dwitia ◽  
Agus Hudoyo ◽  
Adia Nugraha
Keyword(s):  
Growth Rate ◽  
Research Data ◽  
Rice Production ◽  
The Self ◽  
Staple Food ◽  
Probability Level ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
Self Sufficiency ◽  
The Government

Rice is the staple food for Indonesian people and Indonesia was in self-sufficiency for rice in 1984. Based on the Agricultural Ministry’s Strategic Planning for 2015 – 2019, the government targeted that the self-sufficiency in rice in 2019 by 82,078 million tons of the rice production. It is better that the production is stochastically forecasted in form of the interval of projection possibility with the certain probability level. Therefore, the objective of this research is to know the growth of rice production and to stochastically forecast it. The data used in this research is the production of rice in the period of 1961 – 2015 obtained from the Food  and Agriculture Organization (FAO), and the Central Bureau of Statistics (CBS), Indonesia. The research data is analyzed by econometric method. The result revealed that the rice production would be 77,487 million tons in 2019 and it was 95% confidence interval would be between 74,901 and 80,071 million tons. The growth rate of the rice production in 2018 – 2020  would be 0.6 percent per year. We could conclude that the government target of the rice production was higher than the result of stochastic forecasting.Key words: forecast, paddy, production

scholarly journals Prediction of genetic merit for growth rate in pigs using animal models with indirect genetic effects and genomic information

2020 ◽  
Vol 52 (1) ◽  
Author(s):  
Bjarke G. Poulsen ◽  
Birgitte Ask ◽  
Hanne M. Nielsen ◽  
Tage Ostersen ◽  
Ole F. Christensen
Keyword(s):  
Growth Rate ◽  
Animal Model ◽  
Genetic Effect ◽  
Predictive Performance ◽  
Genetic Effects ◽  
Relationship Matrix ◽  
Genomic Information ◽  
Indirect Genetic Effects ◽  
Group Members ◽  
Direct Genetic Effect

Abstract Background Several studies have found that the growth rate of a pig is influenced by the genetics of the group members (indirect genetic effects). Accounting for these indirect genetic effects in a selection program may increase genetic progress for growth rate. However, indirect genetic effects are small and difficult to predict accurately. Genomic information may increase the ability to predict indirect genetic effects. Thus, the objective of this study was to test whether including indirect genetic effects in the animal model increases the predictive performance when genetic effects are predicted with genomic relationships. In total, 11,255 pigs were phenotyped for average daily gain between 30 and 94 kg, and 10,995 of these pigs were genotyped. Two relationship matrices were used: a numerator relationship matrix ($${\mathbf{A}}$$ A ) and a combined pedigree and genomic relationship matrix ($${\mathbf{H}}$$ H ); and two different animal models were used: an animal model with only direct genetic effects and an animal model with both direct and indirect genetic effects. The predictive performance of the models was defined as the Pearson correlation between corrected phenotypes and predicted genetic levels. The predicted genetic level of a pig was either its direct genetic effect or the sum of its direct genetic effect and the indirect genetic effects of its group members (total genetic effect). Results The highest predictive performance was achieved when total genetic effects were predicted with genomic information (21.2 vs. 14.7%). In general, the predictive performance was greater for total genetic effects than for direct genetic effects (0.1 to 0.5% greater; not statistically significant). Both types of genetic effects had greater predictive performance when they were predicted with $${\mathbf{H}}$$ H rather than $${\mathbf{A}}$$ A (5.9 to 6.3%). The difference between predictive performances of total genetic effects and direct genetic effects was smaller when $${\mathbf{H}}$$ H was used rather than $${\mathbf{A}}$$ A . Conclusions This study provides evidence that: (1) corrected phenotypes are better predicted with total genetic effects than with direct genetic effects only; (2) both direct genetic effects and indirect genetic effects are better predicted with $${\mathbf{H}}$$ H than $${\mathbf{A}}$$ A ; (3) using $${\mathbf{H}}$$ H rather than $${\mathbf{A}}$$ A primarily improves the predictive performance of direct genetic effects.

Impediments Faced By Women SHGs under Integrated Watershed Management Programme

2016 ◽  
Vol 32 (1) ◽  
Author(s):  
M. K. BARIYA ◽  
P. R. Kanani ◽  
S. J. Parmar
Keyword(s):  
Watershed Management ◽  
Interpersonal Trust ◽  
Management Programme ◽  
The Self ◽  
Bank Account ◽  
Self Help ◽  
Integrated Watershed Management ◽  
Group Members ◽  
Marketing Information ◽  
Self Help Group

The present study was an attempt to identify the impediments faced by SHGs under Integrated Watershed Management Programme (IWMP). A total of 90 women self help group members as respondents were selected from Amreli district of Gujarat. The study findings revealed that the self help group women mainly encountered with the lack of knowledge in record maintenance. Their dependency on family male member was another impediment in solving money problems. Handling of bank account in which SHG Women were unaware of the rules has continuation of project and its expansion in other villages by establishing new SHG and addition of new activities have been largely suggested by most SHG-women. Although they were found not competent in performing bank formalities, yet their co-ordination among members and interpersonal trust were intact. Internal loaning and loaning through bank, clashes in their loan taking time, lack of time for meeting, dependency on members of family, and lack of marketing information needed major reforms as suggested by SHG members.

Growth of SiC Single Crystal from Si-C-(Co, Fe) Ternary Solution

2006 ◽  
Vol 527-529 ◽  
pp. 115-118 ◽  
Author(s):  
Nobuyoshi Yashiro ◽  
Kazuhiko Kusunoki ◽  
Kazuhito Kamei ◽  
Mitsuhiro Hasebe ◽  
Toru Ujihara ◽  
...  
Keyword(s):  
Growth Rate ◽  
Silicon Carbide ◽  
Single Crystal ◽  
Grown Crystal ◽  
Crystalline Silicon ◽  
The Self ◽  
Ternary Solution ◽  
Single Crystalline Silicon ◽  
Carbon Solubility ◽  
Ternary Solutions

We carried out the growth of single crystalline silicon carbide (SiC) from Si-C-X (X= Co, Fe) ternary solutions. These ternary solutions are expected to show large carbon solubility compared with Si solvent (self-flux) by means of CALPHAD (CALculation of PHAse Diagrams) method. We investigated the growth rate and the polytype of the grown crystal from the ternary solutions. Then we found that the growth rate from the ternary solutions is much larger than that from the self-flux. The growth rate from Si-C-Co (Si-C-Fe) system was about 6mm/hr (12mm/hr) while that from the self-flux was only 2mm/hr. The grown crystal from the ternary solutions is classified into 6H that takes over the seed polytype.

Individual variation and interrelationships between swimming performance, growth rate, and feeding in juvenile rainbow trout (Oncorhynchus mykiss)

1998 ◽  
Vol 55 (7) ◽  
pp. 1583-1590 ◽  
Author(s):  
T Ryan Gregory ◽  
Chris M Wood
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Plasma Cortisol ◽  
Positive Relationship ◽  
Swimming Performance ◽  
Individual Performance ◽  
Significant Positive Relationship ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

Variation among individuals in specific growth rate (SGR), feeding, and two measures of swimming performance and their possible interrelationships were investigated in juvenile rainbow trout (Oncorhynchus mykiss) kept in groups on either satiation or half-satiation rations. Maximum sustainable velocity (Ucrit) was measured as an index of aerobic swimming performance and stamina (fatigue time in a fixed-velocity test at 6 body lengths ·s-1) as an index of anaerobic performance. Individual performance in both of these tests was found to be significantly repeatable. Trout fed on half-satiation ration exhibited significantly lower mean values of SGR and body size and higher levels of aggression-related fin damage, but no significant differences in stamina, relative or absolute Ucrit, glycogen content, or plasma cortisol. However, in these fish, there was a significant negative relationship between SGR and relative Ucrit, a significant positive relationship between SGR and stamina, and a significant positive relationship between SGR and total daily meal. None of these relationships were seen in fish fed to satiation. Plasma cortisol and tissue glycogen stores were not related to SGR. These results indicate that under the intensified competition of restricted ration, there are trade-offs between growth, feeding, and different types of swimming performance.

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