Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
carbohydrates improved growth and feed utilization
of the fish (Tan et al, 2006).
Although both proteins and carbohydrates
contribute to the development of the organism, the
influence of each nutrient is not essentially equal to
the other (Lovell, 1991). Since each component has
various effects on the development of the fish, its
effect on growth was evaluated. In the current study,
growth of fifteen juvenile goldfish was observed
before and after exposure to three different diets: a
high protein, a high carbohydrate and a combination
diet comprising of both elements. Growth was
measured as an increase in body size, change in body
condition and overall weight gain. As mentioned
earlier, each nutrient has variable influence on
growth; therefore, there should be a difference in
growth or in the net weight gain of the goldfish
between the different diets.
Materials and Methods
Experimental Diets
Fifteen juvenile goldfish obtained from PetSmart
at Mission Viejo, California were used in the study
and were maintained in aerated, filtered water in
three separate glass aquarium tanks. The goldfish
were divided evenly into the three separate tanks and
each tank was designated a different diet. Group A
were given Micro Pellets (Kyorin Food Industry,
Japan) with high protein content, Group B were given
Baby Brine Shrimp Cubes (San Francisco Bay
Manufacturing; Newark, California) with high
carbohydrate content, and Group C were given
TopFin Flakes (Pacific Coast Distributing, Phoenix),
the control treatment, which contains both
carbohydrates and proteins.
When coupled with organic wastes discharged by
the fish, excess feed in the tanks decreases dissolved
oxygen in the water, which also decreases appetite
and growth rate; hence, tanks were cleaned everyday
before administering new sets of food, to ensure
suitable environment for survival (Cacho et al, 1991).
Weight Measurements and
Calculations
Each fish was weighed before the trial. Fish was
removed from the tank using a net and was placed
into a bucket containing tank water to carry out the
measurements. Each fish was placed in a tared glass
container of tank water on an electronic balance
(Biology Department, Saddleback College) for body
weight measurements, before being returned to their
original tanks.
Environmental changes, such as changes in
temperature or pH levels, can cause stress to the
normal physiology of the fish (Smith, 1966). In order
to minimize stress, the groups were allowed to
acclimatize to their new environment for one week
prior to exposure to the different diets. After
acclimatization for one week, each group was
introduced to its new diet and was fed 1 gram of the
food every 12 hours. Each group was given the same
type of food for one week and subsequent weight
measurements were made every week using an
electronic balance. The study was conducted at room
temperature (25–30 ºC) for four weeks in Mission
Viejo, California starting February 24, 2008 to March
12, 2008 and changes in growth were evaluated.
Percentage of weight gained was obtained by using
the nutritional index (Eq.1) (Bandyopadhyay et al,
2005):
Equation 1.
Net Weight Gain = Final weight – Initial weight
Weight Gain (%) = Net Weight Gain
Food Analysis
Initial weight
X 100
Percentage %
Protein Carbos Fat Fiber Phosph
orus
(A) 49.0 20.0 4.0 0.8 2.0
(B) 3.0 42.0 1.5 0.2 0.1
(C) 39.0 43.0 9.0 2.0 1.0
Table 1. Percent composition of diets administered
to fish during trial. Percentage of vitamins and other
minerals are not included in the overall composition
of the food. Values acquired from each food
container.
Results
Average initial weight measurements were 1.53 ±
0.24 g for Group A, 1.48 ± 0.12 g for Group B and
1.41 ± 0.07 g for Group C. Growth difference
between the three experimental diet groups was
demonstrated by the average final weight
measurements obtained from the fish in comparison
to its initial weight (Table 2). The results of the
study indicate that there was a significant difference
in growth observed between the groups of fish when
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Saddleback Journal of Biology
Spring 2008