Oreochromis Niloticus Lab Report

Parallel Correlation of Oreochromis Niloticus

Digestive System Morphometrics to its Feeding Habit

San Pedro, Dannica Joyce C.

I. Intoduction

Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream.

Natural food and feeding habits of tilapia. Early juveniles and young fish are omnivorous, feeding mainly on zooplankton and zoobenthos but also ingest detritus and feed on aufwuchs and phytoplankton. At around 6 cm TL the species becomes almost entirely herbivorous feeding mainly on phytoplankton, using the mucus trap mechanism and

1. Labeled external anatomy of Oreochromis Niloticus.

Fig. 2. Extraction of Oreochromis Niloticus digestive system

Fig. 3. Digestive System of Oreochromis Niloticus: (A) Gills, (B) Liver ,(C) Stomach ,(D) Intestine measured as 122.08 cm.

SPECIES WEIGHT (g) BODY LENGTH (cm) BODY WIDTH (cm)

Tilapia 150 g 18.3 cm 7.9 cm

Table 1. Weight, Body Length, and Body Width of Oreochromis Niloticus

ORGAN LENGTH (cm) WEIGHT (g)

Gills 3.2 cm 2.64 g

Liver 2.3 cm 0.85 g

Stomach 2.5 cm 1.27 g

Intestine 122 cm 3.55 g

Table 2. Measurements for Internal Organs

Using the obtained data from the measurements, the Relative Gut Length (RGL) of Oreochromis Niloticus was computed by determining the ratio of intestine to the body length. The Viscerosomatic Index (VSI) and Hepatosomatic Index (HSI) were computed using the following formulas:

VSI = Viscera Weight/Body Weight x 100

HIS = Weight of Liver/ Body Weight x 100

The table below shows the complete Relative Gut Length, Viscerosomatic Index and Hepatosomatic Index for Oreochromis Niloticus.

ORGAN RGL VSI HSI

Gills - 1.76% -

Liver - - 0.56%

Intestine 6.666% - -

Table 3. RGL, HIS and VSI of Oreochromis Niloticus

IV. Results

A. External

Higher HSI indicates higher energy reserve in animals. Viscerosomatic Index (VSI) was used to assess the nutritional and physiological status of the fish. I was able to get the VSI of the gills and unable to get the value of other organs, it is said that high value of VSI for fishes can be linked to their feeding habits and nutritional content of its consumed food.

VI. Conclusion & Recommendation

Tilapia had a RGL value of 6.666%, as a result of computing its digestive tract's length I therefore conclude that tilapia is an omnivore. It is said that they feed on both aquatic plants and planktons.

Tilapias are omnivores, and as such have a low requirement for fishmeal and fish-oil in their diets, making them a net producers of protein and therefore a valuable aquaculture species.

For us to be able to dissect successfully , get a bigger fish that is easier to detach the organs out. The size of the species really matters when it comes to identifying its parts. It allows us to have a clear view and a good observation from it. Just remember that before starting the dissection you need to know the step by step procedure and get all the materials needed. And then apply the procedure and be sure to write down every details that can you