Tropical foods are subject to numerous laboratory tests and they are successfully used in the company’s aquaria as well as tanks of other breeders. But that’s not all. We also entrust the foods we’ve been producing for more than 45 years to various teams of scientists. They have proper knowledge and experience to conduct even most difficult experiments for us. This time, the aim of the study was to determine the effect of two selected foods – Vitality & Color Granules and Tropical Granules on the coloration of aquarium fish. At the same time, they also checked how the fish accepted the food and how it affected their growth.
Preparing for the experiment
In order to conduct a reliable experiment on the effect of food on fish coloration, we had to involve fish. We chose three spot gourami (Trichogaster trichopterus known as “gold”). Why exactly this species? Well, this was my idea becauee I have already successfully used these fish for such an experiment in the past, but under breeding conditions. Since the young fish are silvery, the effect of the color change is very visible on them. From a flock of young gouramis with a body length of about 2-3 cm after acclimatization, 80 individuals were selected and randomly divided into two experimental groups. Four replicates were included in each group (each replicate was an individual aquarium stocked with 10 individuals).
|The number of groups||2||The number of fish in the replicate||10|
|Number of replicates (aquariums) in a group||4||The number of fish in the group||40|
|Total number of replicates (aquariums)||8||Total number of fish||80|
What did the experimental aquariums look like?
The researchers prepared 8 tanks measuring 35 x 30 x 35 cm (L x W x H). Their gross volume was 36.75 l, and the net volume was 30 l. The aquariums were equipped with internal filters with a capacity of up to 250 l/h and a filter bed volume = 1 l. In addition, they were aerated by a system powered by a HIBLOW HP 40 blower (1.6 l of pumped air/min/acquarium). The aquariums used LED lighting. They were mature before the fish were introduced.
Foods selected for the experiment
There is a rule that in comparative studies samples are usually coded. This was also the case here. The scientists received two foods labeled A and B. Now I can reveal what was hidden under these letters:
When choosing the foods for the experiment, we wanted to see what difference there is, and if there is any, in the coloration effect of the basic fish food and the color-enhancing food. For comparison, we chose Vitality & Color Granules, which has recently been modernized and now contains a higher dose of astaxanthin and the addition of red pepper extract, and Tropical Granules, a food from the Standard Line, which is a basic, multi-ingredient food and does not contain high-carotenoid raw materials.
Course of the experiment
The fish were fed every morning between 8:00 and 8:30 am. During acclimatization period, they were able to eat as much as they wanted. After each such feeding, the amount of food intake was monitored to determine the dose of food used in the actual part of the experiment. On the 1st, 10th and 20th days of the test, the fish were fed to visual satiation, while during the remaining period (days 2-9, 11-19, 21) they received only 50% of the maximum daily intake.
This feeding regime made it possible to determine the acceptability of the tested foods. Every day, thirty minutes after feeding, waste was removed from the bottom of the aquariums and the condition of the lighting, filters and aerators was checked. Three times a week (Monday, Wednesday, Friday), 20% of the volume of water in each experimental aquarium was changed. As you can see, a lot of work has been done, and we haven’t reached the data collection part yet…
What data were collected during the experiment?
The effect of food on coloration was evaluated. You are probably wondering how it was done. Well, surveys were conducted to assess the appearance and vitality of the fish, and survey participants did not know how many experimental groups there were and what the purpose of the test was. The surveys were conducted on the 21st day of the test. In addition, a documentary was shot. In each aquarium, fish were recorded for 5 minutes on the 1st, 7th, 14th and 20th days of the test. During recording, the lighting parameters were kept the same every time. The images obtained from the recordings were evaluated ion in computer a graphics program, which analyzed the individual components of a given color in the image, which is no longer possible for the human eye. Therefore, the evaluation of coloration was done subjectively (questionnaires) and objectively (computer analysis).
The experiment also collected the data needed to determine the fish’s growth and food utilization. To do this, we measured how much food the fish were taking in, how they were growing, and what their final weight was. The food conversion ratio (FCR) was also determined. Feed Conversion Ratio refers to the amount of food consumed per kilogram of animal weight gain:
FCR = feed intake (kg) / weight gain (kg)
Thus, the lower its value, the better the food is utilized.
We also provided data on the environmental conditions in which the fish lived. We recorded water temperature(°C), pH (pH), dissolved oxygen content (mg/l), ammonia (mg/l), nitrite (mg/l) and nitrate (mg/l) levels.
Results of the experiment
It’s time to reveal what came out of all this. The collected data was analyzed using statistical tools.
Effect of foods on fish’s coloration
Statistical analysis of the data obtained showed a significant effect of the tested foods on the body coloration and vitality of the fish. The best coloration enhancement was observed in fish fed with Vitality & Color Granules. As we assumed, Tropical Granules only slightly improved the coloration of the fish. It is worth noting that coloration enhancement, although slight, was noticeable, even though this product does not contain special additives such as astaxanthin or red pepper. However, like all Tropical foods, Tropical Granules also contains raw materials in its formula that provide fish with the necessary dose of carotenoids.
Color-enhancement in fish fed with Vitality & Color Granules
Color-enhancement in fish fed with Tropical Granules
Physical and chemical parameters of water
The water temperature in the aquaria averaged 26.8°C and ranged from 26.0°C to 28.0°C. The water pH averaged 7.43 pH, with fluctuations ranging from 7.22 to 7.69 pH. The level of dissolved oxygen in the water at each measurement was determined to be high, the minimum value was 7.54 mg/l, the maximum value was 9.02 mg/l, and the average value was 8.46 mg/l. The average content of nitrogenous compounds in the water was: ammonia 0.01 mg/l, nitrites 0.05 mg/l, nitrates 3 mg/l. No connection was noted between the analyzed water quality parameters and the type of food fed.
Each aquarium was stocked with ten fish. The test was started with individuals with an average body weight of 1.04 g. Animal survival did not differ between groups. None of the foods tested had any effect on mortality rates.
Food intake and feed conversion rate
The unit intake of Vitality & Color Granules and Tropical Granules was 0.20 g and 0.24 g, respectively. It is worth noting that unit weight gain was higher in fish fed Vitality & Color Granules (0.19 g) compared to Tropical Granules (0.1 g).
As a result of the different weight gain and feed intake in the two groups, the feed conversion ratio (FCR = feed intake (g) / weight gain (g)) was 1.05 for Vitality & Color Granules and 2.41 for Tropical Granules.
Now you know that the food Vitality & Color Granules actually works and effectively improves fish coloration. And all thanks to the astaxanthin (84 mg/kg), red pepper extract (3000 mg/kg), shrimp (10%) and krill (8%) present in its composition.
Interested in the topic of fish coloration, be sure to read Colour-enhancing foods foods – how do they work?