The Difference of Metabolic Rate of Avian Eggs During Incubation
Chelsea Roche and Frank Leon
Department of Biological Sciences
Saddleback College
Mission Viejo, CA 92692
(single space abstract title)
Metabolic rate is an important measurement of all of the body’s functions. It
can be measured by oxygen consumption or by the production of carbon dioxide.
Both methods of measurement encompass body functions such as gas exchange,
organ function and the overall health of an individual. Metabolic rate increases as
the gestational period goes on, and is also dependent on the size of the organism
(split into more than one sentence). (should explain here that there were two
experiments conducted) In this experiment, the metabolic rate of (WHAT KIND OF
BIRDS) avian eggs was (<-were) measured in relation to the point in the gestational
period. Measurements were taken at the beginning, middle, and end of gestation and
calculated in terms of mL CO2*g-1*min-1. The original experiment tested the
metabolic rates of chicken, ducks and quail eggs against each other with relation to
weight of the egg, but investigators encountered an experiment-altering problem in
which the majority of the eggs were not fertilized, as they were supposed to have
been (split into more than one sentence). Investigators adapted (adapted?) and used
the five quail eggs that were fertilized and developing (developing embryos) to
measure the metabolic rate (measure the metabolic rate of WHAT?) in beginning,
middle, and end of the gestational periods. The average carbon dioxide production
was calculated for comparison purposes. An ANOVA test was run, with a p-value of
0.046 followed by a Post-Hoc Bonferroni Comparison. and (split into more than one
sentence) it was found that there was a statistical difference between the middle and
late gestational periods (t=2.807). The statistical difference was present because an
unexplained event (why isn’t there an explanation?) occurred where (which caused)
all of the fetuses died in-utero. There was no statistical difference in beginning to
middle of the gestational periods (?=1.690), or beginning to end of gestation
(t=1.117)(split into more than one sentence).
abstract can be shortened to 1)problem, 2)experimental methods, 3)results and
4)appropraite statistics
Introduction
The process in which a bird broods its eggs is vital to the success of the population.
The term brooding is defined as an inherent behavioral characteristic present in the class
Aves, that means to sit on a clutch of eggs to incubate them (Ekarius, 2007). The body heat
from the presence of the parent provides a constant temperature that is necessary to
promote embryonic growth and development. The heat present from incubation provides
the energy needed to drive molecular interactions and enzymatic activities. Oxygen drives
phosphorylation through a pressure gradient created by the embryo’s oxygen
consumption. Carbon dioxide and water vapor diffuse in the opposite direction creating a
metabolic process in which the embryo will grow from. Towards the end of incubation,
breathing like movements? begin and the beak pierces the air cell to fully develop the lungs
(Mortola, 2009), (NEW SENTENCE) marking the end of the dependence of the embryo on
the egg for metabolic processes during development.
The size of the egg and the incubation time are directly related. There is no
significant direct relationship, however, to the size of the bird and the size of the egg.
Smaller species lay relatively larger eggs in comparison (to) of body size and egg size. The
varying incubation times are significant in determining the maturity of the bird at hatching
time. In altricial species, the hatchlings are completely dependent on parental care while
precocial species that are born after longer incubation periods are born with their eyes
open and are more developed than the former (Hoyt, 1980). All eggs used in this
experiment are precocial species. (last sentence should be placed before you define altricial
and precocial species)
Metabolism in developing embryos has been measured in the form of heat and
oxygen consumption. The metabolic rate increased during development and plateaued just
prior to hatching. Metabolic rate is proportional to egg mass and inversely proportional to
incubation time (Karlsson, 2007). The incubation time for all three species varies. The
common chicken’s (common chicken?) incubation time is 21 days, the duck’s incubation
time is 26-28 days and the quail’s incubation time is the shortest at 16-17 days.
Investigators hypothesized that the duck will have the highest metabolic rate, and
that metabolic rate will be at it’s (<-remove ‘) highest just before pipping?. This hypothesis
is supported by numerous studies done on the metabolic rate of eggs based on size and the
different points in the gestational period (citation).
Materials and Methods
Investigators obtained 12 fertilized duck eggs, 12 fertilized quail eggs and 12
fertilized chicken eggs from Wagon Train Tack and feed in Orange, California. An incubator
and a turner were also rented to insure a good (successful?) hatching. Water was placed in
the incubator to keep humidity at 65%, the amount needed for all three species. The
incubator was turned on and allowed to reach 37C. All eggs were placed in the turner,
which would rotate the eggs every hour like they (how are ‘they’ rotated in the wild?)
would be in the wild. This insures that the eggs (eggs?) do not get stuck to the shell, and are
allowed to grow in equal proportions all around their bodies. The eggs were left for a
period of a week in which temperature and humidity were checked every day. After a week,
the first measurements were taken for all three species and divided thereafter by the time
left in the gestational period and measurements were taken accordingly (split up into more
than one sentence). The mass of each egg was taken and recorded before each
measurement. Measurements were taken using a Pasco GLX probe, which measured the
amount of carbon dioxide produced. Eggs were set in a sealed container, which was then
placed in an incubator set at 37C. Carbon dioxide production was measured for ten
minutes and graphed on the Pasco GLX. The data was then transferred to a laptop and
graphed on excel to measure the slope and R2 value. The data was divided by 1000 to get
the carbon dioxide in mL, divided again by the volume of the container used to capture
data, and then divided yet again by the mass of each egg.
Results
After encountering difficulties with fertilization of 31 of the 36 eggs, only five quail
eggs were used to gather data, as they were the only eggs that underwent some sort of
development. An ANOVA test was run to compare the averages of CO2 produced by the five
eggs at three different gestational periods, beginning, middle, and end with a p-value of
0.046 (Figure 1). According to the Post-hoc Bonferroni comparison, there were statistical
differences between the middle and end of the gestational period (t=2.807), but not
between the beginning and end (t=1.117), or the beginning and middle (t=1.690). The
average of the beginning of all five eggs was 0.256 mL*g-1*min-1. The average of the middle
gestational period was 0.274 mL*g-1*min-1 and (new sentence) the average of the late
gestational period was 0.119 mL*g-1*min-1.
Figure 1: The average of the production of CO2 by the five quail eggs at beginning, middle and
end of gestation. (provide more information about your graph. was there a difference
between the values?, p-values?)
Discussion
The results indicated that there was a difference in metabolic rate in the early stages
of avian development. The current experiment supported previous work (work?)(Mortola,
2009) that the metabolic rate of the avian egg size increased during the early and middle
stages of the gestational period (citation). An increase in carbon dioxide production
indicated an increase in metabolism, likely due to the development of organs. Later in the
gestational period, the production of carbon dioxide decreased, signifying a decrease in
metabolic rate for all five quails. Investigators suspect that development was halted for an
unexplained reason (no explanation?). All research and knowledge of metabolism of Avian
eggs supports the theory that metabolism should be at it’s highest just before pipping, but
this was not the case, indicating that something was wrong. After the hatch date had been
passed by a week for the quails, investigators broke open portions of the eggs to find that 7
of the 12 quail eggs were not fertilized, and 5 had died unexpectedly during development
(SPLIT INTO TWO SENTENCES). This prompted an investigation to the rest of the eggs in
which the candle method was used, where a hole was cut in a dark piece of construction
paper and a light was shone through it to see where the rest of the eggs were in their
developmental stages (<-SHORTEN SENTENCE). Investigators were shocked to find that 31
of the 36 eggs were unfertilized and not developing, rendering the original experiment
impossible. Investigators adapted to the situation and changed the experiment to use the
data that they had collected for the five quails during varying gestational periods. Instead of
measuring avian egg size versus metabolism as the original experiment outlined,
investigators measured the carbon dioxide production versus the period of incubation. It
was found that carbon dioxide did increase, as it should, from the beginning to the middle,
but at the end of gestation which was the only statistically significant comparison,
according to the Bonferroni comparison, carbon dioxide production decreased
significantly.
Acknowledgements
Investigators would like to thank Steve Teh, for his knowledge and expertise.
They would also like to thank their classmates for the moral support they provided for the
duration of this experiment.
Literature Cited
Birchard, G.F and Deeming, D.C. (2009). Avian eggshell thickness: scaling and maximum
body mass in birds. Journal of Zoology 279: 95-101.
Ekarius, Carol (2007). Storey's Illustrated Guide to Poultry Breeds. 210 MAS MoCA Way,
North Adams MA 01247.
Hoyt, Donald and Rahn, Hermann (1980). Respiration of Avian Embryos. Respiration
Physiology 39: 255-264
Karlsson, Ola and Lilja, Clas (2007). Eggshell structure, mode of development and growth
rate in birds. Zoology 111: 494-502.
Mortola, Jacob P. (2009). Gas Exchange in avian embryos and hatchlings. Comp. Biochem.
Physiol. Part A 153: 359-377.
Review Form
Department of Biological Sciences
Saddleback College, Mission Viejo, CA 92692
Author (s): Chelsea Roche and Frank Leon
Title: The Difference of Metabolic Rate of Avian Eggs During Incubation
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.
Two experiments were conducted on embryonic chickens (Gallus gallus domesticus).
The first experiment tested the metabolic rates of chicken, ducks and quail eggs
against with one another. the problem of the first experiment was that not all the
eggs were fertilized. In the second experiment they used 5 quail eggs containing
developing embryos to measure the metabolic rate sorry the beginning, middle, and
end gestational periods.
General Comments
Generally explain the paper’s strengths and weaknesses and whether they are serious, or important to our
current state of knowledge.
The researchers knew exactly how to go about this study. They did a great job at providing
information on both their first and second experiments. they also paid attention to the
reader and defined or elaborated on words not common to everyone.
Technical Criticism
Review technical issues, organization and clarity. Provide a table of typographical errors, grammatical errors,
and minor textual problems. It's not the reviewer's job to copy Edit the paper, mark the manuscript.
This paper was a final version
Grammar
revise
This paper was a rough draft