Effects of Photoperiod, Temperature, and Population Density on Induction of Diapause Egg Production in Eurytemora Affinis (Copepoda: Calanoida) in Lake Ohnuma, Hokkaido, Japan

1992 ◽  
Vol 12 (3) ◽  
pp. 361-367 ◽  
Author(s):  
Syuhei Ban
Keyword(s):  
Population Density ◽  
Egg Production ◽  
Eurytemora Affinis

Induction of diapause egg production in Eurytemora affinis by their own metabolites

Hydrobiologia ◽  
1994 ◽  
Vol 292-293 (1) ◽  
pp. 185-189 ◽  
Author(s):  
Syuhei Ban ◽  
Takashi Minoda
Keyword(s):  
Egg Production ◽  
Eurytemora Affinis

LAYER PERFORMANCE IN COLONY CAGES AS RELATED TO STOCKING DENSITY AND POPULATION SIZE

1977 ◽  
Vol 57 (4) ◽  
pp. 785-792 ◽  
Author(s):  
A. T. HILL
Keyword(s):  
Population Density ◽  
Population Size ◽  
Feed Efficiency ◽  
Egg Production ◽  
Egg Quality ◽  
Stocking Density ◽  
White Leghorns ◽  
High Level

Two commercial strains of White Leghorns were each measured for egg production, egg quality, feed efficiency and net egg income over feed and bird costs. The birds were in populations of 18, 24 and 30 per colony cage each at densities of 310, 387 and 464 cm2 per bird. In addition, a 10th population–density combination of 24 birds, caged singly at 619 cm2, served as controls. A total of 3,840 birds were measured for 60 wk in two tests, each with four replications. Results were also related directly to an earlier experiment with populations of 3, 6 and 12 birds per cage at the same densities. The performances of populations of 18, 24 and 30 birds were equal and poor relative to the controls. All three populations at 387 cm2 per bird were superior to those at 310 cm2 and equal to 464 cm2 in egg production and net egg income. In comparisons with more conventionally caged populations of 3, 6 and 12 birds, colony caged layers yielded significantly (P < 0.01) fewer eggs and less net egg income. Mortality was significantly (P < 0.05) greater for colony caged layers. It was concluded that the general high level of stress in colony cages prevented the expression of declining performance normally expected with population increases, yet effects due to density were still evident.

scholarly journals EFFECTS OF POPULATION DENSITY ON ENERGY UTILIZATION, INTESTINAL DISACCHARIDASES, AND ADRENAL FUNCTION IN HENS

1972 ◽  
Vol 52 (1) ◽  
pp. 103-112 ◽  
Author(s):  
K. Y. LEI ◽  
M. P. STEFANOVIC ◽  
S. J. SLINGER
Keyword(s):  
Fatty Acids ◽  
Population Density ◽  
Egg Production ◽  
Starch Content ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Feed Consumption ◽  
Bird Density ◽  
Total Fatty Acids ◽  
Adrenal Corticosterone

Two experiments were carried out with laying hens to determine the effect of overcrowding stress on reproductive performance and on certain other parameters that might be expected to be affected and thus be useful indices of this type of stress. The first experiment consisted of eight treatments in a factorial arrangement with four bird densities of one, two, three, or four birds in 30.5 × 45.7-cm (12 × 18″) cages and two levels of dietary energy. The second experiment involved three bird densities of one, three, and five birds in 30.5 × 45.7-cm cages fed a single diet. There were four replicate cages per treatment in both experiments. Feed consumption, weight gain, and egg production were not significantly affected by the population densities employed in experiment 1. In experiment 2, increasing bird density significantly reduced egg production, and hens maintained at five per cage suffered a net loss of body weight. In neither experiment was energy utilization affected by crowding since the dietary metabolizable energy values remained constant. In both experiments mucosal maltase and sucrase activities were significantly increased with increasing bird density when birds were fed diets of relatively normal starch content. Plasma-free fatty acids, total fatty acids, and triglyceride levels were not significantly affected by population density, nor were the oleic–linoleic–arachidonic acid levels expressed as percentages of total fatty acids. It would thus appear that lipid metabolism remained relatively normal in hens subjected to overcrowding stress. The levels of peripheral plasma corticosterone and adrenal corticosterone increased in a linear fashion in both experiments with increasing bird density. It would appear that plasma and adrenal corticosterone levels might be useful indices of overcrowding stress in hens.

scholarly journals Effect of adult population density on egg production in the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae)

2016 ◽  
Vol 33 (2) ◽  
pp. 92-95 ◽  
Author(s):  
kwanho Park ◽  
Wontae Kim ◽  
Eunsun Kim ◽  
Ji-Young Choi ◽  
Sung-Hyun Kim
Keyword(s):  
Population Density ◽  
Egg Production ◽  
Adult Population ◽  
Black Soldier Fly ◽  
Hermetia Illucens
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