Fishew Ii 1 Tiwi.docx

DIGESTION RATE ON FISH

By : Name Student ID Entourage Group Assistant

: Pratiwi Kusuma Kurniawati : B1B017007 : VI :3 : Afif Ghalib Ammar Zain

PRACTICAL REPORT OF ANIMAL PHYSIOLOGY II

MINISTRY OF RESEARCH, TECHNOLOGY AND HIGHER EDUCATION JENDERAL SOEDIRMAN UNIVERSITY FACULTY OF BIOLOGY PURWOKERTO 2019

I. INTRODUCTION A. Background Digestion is the process of breaking complex foods into simpler substances. The process of digestion takes time in digesting the food, and the time needed to digest the food is called the rate of digestion. The food consumed by fish will undergo a process of digestion in the digestive system before the feed nutrients are absorbed which will be utilized for biological processes in the body. The process of digestion in the digestive system of the fish will involve digestive enzymes produced by the body. The results of the digestion process are in the form of amino acids, fatty acids, and monosaccharides which are absorbed by the intestine epithelium then spread throughout the body by circulating systems (Kay, 1998). Catfish (Clarias gariepinus) belong to the omnivorous group. Natural food consists of plankton, small crustaceans, snails, worms, mosquito larvae and so on. Catfish that cultivated in ponds, it additional food can be in the form of fine bran, remnants of the kitchen, snail meat, maggots and pellets, because catfish are classified as omnivores. Catfish is very greedy if given any food, to the extent that the carcass is eaten so that it is also classified as a scavenger. On spreading too high, then in a state of hunger can cause mutual prey (cannibals) (Santoso, 1994). Food is needed to produce energy as a body building material, basic metabolism, movement, production of sexual organs, maintenance of body parts, enhancing body fluids, replacing damaged body cells and helping other physiological processes that take place in the body. A number of foods eaten by fish, ± only 10% are used to grow or add weight. While the rest is used for energy or indeed cannot be digested. The amount of weight of food needed for growth or adding to the body's body is called change value or conversion (Schmitdt & Nielsen, 1990). Feeding is the only energy investment that directly affects allocation and utilization of energy in energy budgets for fishes. Many ecological factors, especially water temperature, affect growth and other metabolic processes by influencing feeding (Zhang et al., 2017). Metabolism is all chemical reactions that occur in the body of living creatures, consisting of anabolism and catabolism. Anabolism is the process of synthesizing small chemical compounds into larger molecules, for example amino acids into proteins. Metabolism is a key component in fish bioenergetics. Most of the knowledge

on fish metabolic rates is derived from respirometric experiments conducted in the laboratory, where environmental complexity is minimized (Enders & Boisclair, 2016). Metabolic rate is influenced by biotic factors and abiotic factors. Biotic factors that affect the metabolic rate include temperature, salinity, dissolved oxygen, carbon dioxide, ammonia, and pH. Abiotic factors include weight, sex, stress, and food ratio. The metabolic process requires energy, while filtering energy from food requires oxygen, the metabolic rate can be predicted from the rate of oxygen consumption (Lestari & Dewantoro, 2018).

B. Purpose The objectives of this laboratory activity is to see the digestion rate or the rate of gastric emptying on fish.

II. MATERIALS AND METHODS A. Materials The tools used in this laboratory activity are 4 units of glass aquarium, dissection kit, analytical scales, and tray. The materials used in this laboratory activity are catfish (Clarias gariepinus), and pellet. B. Methods The methods that we use in this practice are : 1. Glass aquarium filled with water as high as 25 cm is prepared and aeration is given. 2. Fish is dispersed in the aquarium. 3. Pellet as much as 2,5% of total body weight of fish is given, and pellet is consumed by fish for 15 minutes. 4. The total body weight of fish is measured. 5. The fish is dissected, fish gastric is taken and weighed as 0 minutes after feeding (Bx). 6. Step 4 and 5 are repeated after 30 minutes (By), and 60 minutes (Bz). 7. Graphic is made.

III. RESULT AND DISCUSSION A. Result Table 3.1. The Result of Observation of Rate Digestion in Catfish (Clarias gariepinus) Entourage VI Group 1 2 3 4

X (0’) Bx (g) Bx (%) 1,12 1,23 1,27 1,3 1,19 1,15 0,92 1,02

Y (30’) By (g) By (%) 0,78 0,82 1,25 1,14 1,12 1,19 1,29 1,17

Z (60’) Bz (g) By (%) 0,99 0,89 0,97 1,01 1,03 0,91 0,95 0,76

Calculation of Group 3: 0’

Bx% =

Bx 1,19  100% = x 100 % = 1,15 % 103 Bxt

30’

By% =

By 1,12 x 100 % =1,19 %  100% = 94 Byt

60’

Bz% =

Bz 1,03  100% = x 100 % = 0,91 % Bzt 113

Digetion Rate

1.5 Group 1

1

Group 2 0.5

Group 3 Group 4

0 Bx%

By%

Bz%

Figure 3.1 Chart of Rate Digestion Observation Result in Catfish (Clarias gariepinus) Entourage VI

B. Discussion The rate of digestion is the rate at which the food from the fish body breaks from complex molecules to simpler molecules and then it will be absorbed by the fish's body. The process of digestion that occurs in the stomach can be measured by knowing the rate of gastric emptying (Elliot, 1997). The rate of digestion can be called a pattern with the process of gastric emptying. The process of fish digestion starts from the gastric (in fish that have gastric) and continues at the intestine which will end up in the waste disposal material. The process of digestion starts from food into the mouth, digests mechanically and is assisted by salivary glands and then enters the pharynx, oesophagus and is accommodated in the gastric to be digested chemically with the help of digestive enzymes. Foods that have become small molecules then enter the intestine to process the absorption or absorption of the rest to the rectum and to the anus to be removed. The results of digestion in the form of amino acids, fatty acids and monosaccharides will be absorbed by the intestine epithelial and then circulated throughout the body by the circulatory system (Gumisiriza et al, 2009). Higher the fiber in fish food, the digestion and absorption of nutrients will decrease, that high fibre in diets could result in increased weight of excreta and reduced nutrient absorption. Moreover, that catfish could not tolerate high level of plant based proteins in their diets due to their low palatability, higher fibre and anti-nutritional content (Adeyemi et al., 2016). Factors that influence the rate of digestion in fish include internal and external. Internal factors include age, body size, activity, stress, and gender. External factors include turbidity (on visibility and O2 content), food and chemical factors in the waters (O2, CO2, H2S, Ph, and Alkalinity). Usually the more fish activity, the more energy will be needed so that the metabolic process is high and requires foods that are of a much better and more abundant quality (Kay, 1998). Digestion rates are influenced by physiological and environmental factors. Body temperature, health, food size and stress result in decreased feed efficiency and nutrient uptake. Based on the Department of Water Affairs and Forestry, the water temperature for optimal growth of fish ranges from 25oC-30oC. Temperatures outside this range will cause fish growth to slow down and decrease resistance to disease, especially those caused by bacteria and fungi (Lusiastuti et al., 2016). Temperature is main factor that determined the digestion rate because the apparent digestibility of fish increases with increases in temperature within

a suitable temperature range. The metabolic rate of fish increased with increases in temperature within a certain range, beyond which the metabolic rate decreased with further temperature increases. As temperatures rise the evacuation rates increase, which may contribute to lower digestibility. In contrast, high water temperatures may result in rapid digestion by high digestive enzyme activity (Zhang et al., 2017). Digestion rates generally correlate with the metabolic rate of fish. The longer the time, the stomach content (BLR) decreases so that the body weight of the fish decreases. Gastric emptying rate is also affected by the food consumed by fish. If digested fish feed comes from vegetable fish feed, then the rate of emptying fish will depend on how much the fish eats feed from plants, because those foods containing extracts from plants contain cell walls containing cellulose so that the fish will be difficult to digest, whereas in fish feed derived from animal fish feed the digestive process will be easy (Lagler, 1977). Increasing the activity of metabolic enzymes causes the metabolic rate to be faster and the level of metabolites in the blood will be higher. The high level of metabolites in the blood causes fish to be hungry and have appetite, so the level of feed consumption also increases (Lestari & Dewantoro, 2018). The higher the temperature, the fish appetite increases, but the increase in temperature at the start of denaturation will reduce the rate of predation, therefore there are two opposite effects, so the optimum point will occur, namely the most appropriate temperature for increasing feed consumption. At the optimum temperature will encourage digestive enzymes to work effectively, thus affecting the activity of enzymes involved in the metabolic process. Metabolic enzymes affect the process of catabolism (producing energy) and anabolism (synthesis of nutrients into new compounds that needed by the body). At temperatures above 32oC catfish larvae begin to decrease appetite and the digestive process is disrupted. The disturbance because digestive enzymes such as proteases which consist of trypsin, chymotiripsin, elastase and carboxy peptidase, amylase enzymes, chitinase and lipase enzymes decrease activity due to denaturation. In the imperfect digestive process, many feces will be produced, so a lot of energy is wasted, but if the activity of digestive enzymes increases, the rate of digestion will also increase, so the level of gastric emptying is high. The high level of gastric emptying causes the fish to get hungry quickly and their appetite increases. Therefore there are two opposing effects, then there will be an optimum point which is the most appropriate temperature for the body's metabolism (Lestari & Dewantoro, 2018).

Catfish (Clarias gariepinus) are all omnivores. The digestive system of catfish starts from the mouth, oral cavity, pharynx, osefagus, stomach, pylorus, intestine, rectum and anus. The anatomical structure of fish mouth is closely related to how to get food. Snoring around the catfish's mouth acts as a food treader or detector and is found in fish that are actively nocturnal. The oral cavity in catfish is enveloped by mucus-producing cells that facilitate the passage of food into the next segment, also there is a taste organ which functions to select food. Pharynx in fish serves to filter food, because the pharyngeal gills are not food-based, they are discarded through gill slits (Fujaya, 2002). Digestion in catfish occurs faster because catfish are omnivorous animals, so food that enters will be easily digested properly in the stomach (Schmidt & Nielsen, 1990). Based on this lab activity we obtained data on the comparison of catfish gastric weight percentage after being fed with a certain time difference. In 0 minute after feeding, the weight of catfish gastric is reached 1,19 gram with weight percentage is 1,15%. In 30 minutes after feeding, the weight of catfish gastric is reached 1,12 gram with weight percentage is 1,19%. In 60 minutes after feeding, the weight of catfish gastric is reached 1,03 gram with weight percentage is 0,91%, Based on this lab activity we obtained at 0-30 minutes the percentage of gastric weight increased and then decreased in 60 minutes, the results obtained were not in accordance with the statement of Rounsefell (1953), that the longer the measurement time after being fed the smaller the weight of the fish gastric. This happens because there are several factors that cause a mismatch of results with reference, there is a mistake in cutting the fish gastric, so it is possible there are still have intestines which are also weighed which can add weight to the scales and fish that are in stress conditions can also affect the catfish diet.

IV.

CONCLUSION

Based on the result can be concluded that are the rate of digestion is the rate of breakdown of food. The digestion rate on catfish in our group (group 3) are 1,15% at the first attempt (0 minute), 1,19% after 30 minutes, and 0.91% after 60 minutes. There is increase the digestion rate after 30 minutes, this can caused by several factor.

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