Influence of Photoperiod on Growth of Green Sunfish, Lepomis cyanellus

1965 ◽  
Vol 22 (6) ◽  
pp. 1379-1386 ◽  
Author(s):  
W. L. Gross ◽  
E. W. Roelofs ◽  
P. O. Fromm
Keyword(s):  
Food Consumption ◽  
Conversion Efficiency ◽  
Fish Growth ◽  
Food Conversion ◽  
Lepomis Cyanellus ◽  
Exposed Fish ◽  
Total Length ◽  
Warmwater Fish ◽  
Green Sunfish ◽  
Food Conversion Efficiency

Four 6-week experiments were conducted to evaluate the effect of photoperiod on growth (total length and weight), food consumption, and food conversion efficiency by green sunfish. Fish were held at constant temperatures in light-tight aquaria under four photoperiods (8-hr constant; 16-hr constant; variable, increasing from 8 to 16 hr; and variable, decreasing from 16 to 8 hr).Growth, food consumption, and food conversion efficiency were all influenced by photoperiod. Food consumption varied directly with the amount of light to which fish were exposed. Fish growth and food conversion efficiency were closely correlated and were generally highest in the increasing, lowest in the decreasing, and intermediate in the two constant photoperiods, but higher in the longer daylength. The results suggest that photoperiod influences growth through increasing conversion efficiency and also possibly through stimulating food consumption.Varying daylength exerts a greater influence on fish growth than a constant daylength. Increasing photoperiod stimulates growth and decreasing photoperiod inhibits growth. This result suggests that the lack of growth of warmwater fish in fall when water temperatures and average daylength correspond to those of spring is largely due to the influence of decreasing daylength.

The early weaning of pigs: I. The effect upon growth of variations in the protein, fat, sucrose, antibiotic, vitamin and mineral contents of diets for pigs of 8–25 lb. live weight and a comparison of wet and dry feeding

1956 ◽  
Vol 48 (2) ◽  
pp. 220-234 ◽  
Author(s):  
H. Smith ◽  
I. A. M. Lucas
Keyword(s):  
Growth Rate ◽  
Food Consumption ◽  
Conversion Efficiency ◽  
Crude Protein ◽  
Live Weight ◽  
Food Conversion ◽  
Growing Period ◽  
Ad Libitum ◽  
Antibiotic Level ◽  
Food Conversion Efficiency

1. The pigs in the three experiments reported were weaned at 10 days old and fed water and drymeal diets ad libitum until they reached 25 lb. live weight. They were housed individually in cages and records were kept of each pig's food consumption and of its live weight every third day.2. Most of the diets fed were based on roller-dried skim milk, rolled oat groats, white fishmeal, sucrose, dried yeast, cod-liver oil, minerals and antibiotic.3. Forty-eight pigs were used in Exp. 1, which was designed as a 4 × 2 factorial. Food-conversion efficiency was significantly improved by 10% when the crude protein in the diet was raised from 24 to 29%. Increasing the protein to 34 or 39% brought no further significant improvement. There were no significant differences between growth rates which were attributable to the four levels of protein.The inclusion of 10% sucrose in the diet did not result in increased food consumption, but there were significant improvements of 8% in growth rate and 10% in food conversion efficiency. There were no treatment interactions.4. Twenty-four pigs were used in Exp. 2, which was designed as a 2 × 2 factorial. Figs fed a diet containing 7% fat grew 4% faster and 6% more efficiently than others fed a diet containing 3·7% fat, but neither difference approached statistical significance. There was no advantage in feeding the meal as a slop, indeed, there was a tendency for the pigs to scour more than on dry feeding. As in Exp. 1 there was no treatment interaction.5. Forty-eight pigs were used in Exp. 3, which was designed as a 2 × 2 × 2 factorial. The basal diet contained about 30% crude protein and 10% sucrose.An increase in the antibiotic level from 18 to 112 mg./lb. diet significantly increased growth rate by 7%, but the 9% increase in efficiency of food conversion was not statistically significant.The addition of a trace mineral supplement significantly improved rate of gain by 7%, but the 6% increase in efficiency of food conversion was not statistically significant.The addition of a complex vitamin mixture had no significant effect upon either rate or efficiency of growth.6. In all three experiments the shape of the growth curve of pigs weaned at 10 days old wag divided into two periods. During the initial ‘check period’, lasting about 10 days, the pigs ate only small amounts of food, grew very slowly, and sometimes scoured. After the ‘check period’ there was a sudden change to the ‘growing period’, during which the pigs ate increasing amounts of meal and grew rapidly.The only treatment which significantly affected the length of the check period was in Exp. 3, when the addition of the vitamin supplement to a diet containing a high antibiotic level shortened the check period by 3 days but then counteracted this advantage by reducing rate of gain during the growing period.7. Between 25 lb. weight and 8 weeks of age twenty-four pigs from the experiments reported were fed ad libitum on a dry-meal diet containing 22% crude protein. The average live weight of these pigs at 8 weeks was 49 lb.

Physiological Responses of Three Species of Fishes to Various Salinities

1972 ◽  
Vol 29 (4) ◽  
pp. 399-405 ◽  
Author(s):  
Robert W. Brocksen ◽  
Ronald E. Cole
Keyword(s):  
Food Consumption ◽  
Conversion Efficiency ◽  
Physiological Responses ◽  
Salton Sea ◽  
Food Conversion ◽  
Optimal Range ◽  
Food Assimilation ◽  
Food Conversion Efficiency ◽  
Experience Difficulty

The effects of varying salinity on parameters such as growth, food consumption, food conversion efficiency, and respiration were determined for three species of fish inhabiting the Salton Sea, California. Bairdiella (Bairdiella icistia), orangemouth corvina (Cynoscion xanthulus), and sargo (Anisotremus davidsoni), were subjected to salinities ranging between 29 and 45‰. The optimal range of salinity was between 33–37‰ for all three species. Growth, food consumption, food assimilation, and respiration were adversely affected at the extreme salinities of 29 and 45‰. The results indicate that the fish inhabiting the Salton Sea will experience difficulty in maintaining populations of the current size when the salinity reaches 40‰.

scholarly journals The effect on mice of practical diets containing different protein and energy levels

1983 ◽  
Vol 17 (4) ◽  
pp. 336-339
Author(s):  
D. J. Ford ◽  
R. J. Ward
Keyword(s):  
Food Intake ◽  
Energy Level ◽  
Food Consumption ◽  
Conversion Efficiency ◽  
Energy Levels ◽  
Bodyweight Gain ◽  
The Other ◽  
Food Conversion ◽  
Before And After ◽  
Food Conversion Efficiency

Mice of 2 strains were fed diets of natural ingredients in 3 different laboratories. The diets, which were fed before and after pelleting, contained levels of protein and energy within the ranges comparable to those found in existing laboratory diets and were the same formulation as those fed to rats in a previous paper. The diet with the lowest energy level supported the lowest rate of bodyweight gain, as it had with rats. Little effect was noticed on food consumption, conversion efficiency or water intake. Animals fed the pelleted diets gained bodyweight faster and there were indications of greater food and water consumption and also food conversion efficiency. It was concluded that food intake was improved with the pelleted diets resulting in the other increases.

Influence of diet pellet hardness and particle size on food utilization by mice, rats and hamsters

1977 ◽  
Vol 11 (4) ◽  
pp. 241-246 ◽  
Author(s):  
D. J. Ford
Keyword(s):  
Particle Size ◽  
Food Consumption ◽  
Conversion Efficiency ◽  
Raw Materials ◽  
Food Utilization ◽  
Food Conversion ◽  
Consumption Growth ◽  
Food Wastage ◽  
Food Conversion Efficiency

Increasing hardness of diet pellets reduced food wastage by each species. Also, less wastage occurred when pellets made from finely ground materials were given, an effect that was not related to hardness. The hardest diet reduced growth of the mice by reducing true food consumption and a poorer food conversion efficiency (true food consumption/growth) was obtained. Apparent food consumption increased with the softness of the diet and food utilization (apparent food consumption/growth) of the softest diets was less efficient than those of the others. Grinding of the raw materials prior to pelleting had no effect on food conversion, but food utilization was less efficient because of the greater wastage of pellets from coarsely ground materials and consequent apparent food consumption.

Effects of chronic ammonia exposure on growth and food conversion efficiency in juvenile spotted wolffish

Aquaculture ◽  
2003 ◽  
Vol 228 (1-4) ◽  
pp. 215-224 ◽  
Author(s):  
Atle Foss ◽  
Tor H. Evensen ◽  
Tone Vollen ◽  
Victor Øiestad
Keyword(s):  
Conversion Efficiency ◽  
Food Conversion ◽  
Spotted Wolffish ◽  
Ammonia Exposure ◽  
Food Conversion Efficiency
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