Growth and Survival Rate of Tilapia ( Oreochromis niloticus ) Receiving Acanthaster planci Based Feed

Crown of thorns star ( Acanthaster planci ) is one of the aquatic organisms that contains protein and amino acids similar to fish meal, and has not been used properly for feed ingredients. This research was conducted to examine A. planci flour as a feed ingredient on the growth of tilapia. The research method was a completely randomized design, consisting of 4 treatments with doses of A. planci flour, 7 %, 14 %, 21 % and 0 % (control), given three replications. The results showed growth (daily growth rate and biomass increase) of 3.84 %, 3.81 %, 4.00 %, and 4.21 % per day, and 61.00 g, 49.33 g, 54.33 g, and 52.67 g. This growth did not show any difference between treatments (P>0.05). Feed consumption ranged from 129.20 g – 132.24 g (P>0.05). Feed conversion ratio and survival rates ranged from 2.13 – 2.75 and 94.44 % - 100.00 % (P>0.05). A. planci flour can be used up to 21 % as a source of protein to reduce the use of fish meal in feed of the fish.


Introduction
Tilapia (Oreochromis niloticus) is a type of freshwater fish consumption. Tilapia has several advantages such as relatively fast growth, tolerance to wide environmental changes, more resistance, and widely consumed (Belton et al., 2009). Because of these advantages, development of Tilapias production in aquaculture became one of an effort to provide animal protein needs for the community.
The best food which plays as a main source of nutrients for fish is very important to push production. Poor management of fish feed can causes low profits because fish feed is the highest cost in aquaculture (Baki and Yücel, 2017). The cause of high feed prices is the availability of raw materials, especially fish meal as the main protein source which is rare and  (Hernandez et al., 2008;Monentcham et al., 2010). An effort to reduce feed price can be done by optimizing the use of vegetable raw materials as a source of protein in fish feed (Jiang et al., 2018;Ariman-Karabulut et al., 2019;2021). Vegetable raw materials are not able to replace fish meal as a source of protein because of their high content of anti-nutritional substances such as phytic acid (Schlemmer et al., 2009;Wang et al., 2009;Chakraborty et al., 2019) and an unbalanced amino acid profile such as methionine, cysteine and tryptophan which are low (Hertrampf and Felicita, 2000;Kaushik et al., 2008). Crown of thorns star flour (Acanthaster planci) alternatively has a high protein and amino acid which might be able to apply as substitute for fish meal (Luo et al., 2011).
Crown of thorns star (A. planci) is an aquatic organism that lives in coral reef ecosystems (Stella et al., 2011: Kayal et al., 2012. In abundant conditions these organisms are caught, dried and stockpiled because they become pests for coral reef ecosystems (Suharsono, 1991;Rotjan and Lewis 2008;Stella et al., 2011;Kayal et al., 2012). These organisms in the form of flour have the potential to used as feed raw materials (Lou et al., 2011). Azlou, (2016) has reported that the use of A. planci flour, as a feed ingredient, has been shown to increase the color of carp. Therefore, this study aims to examine the effect of using A. planci flour as a feed raw material on the growth and survival of tilapia (O. niloticus).

Location
This research is located at the Tadulako University Fisheries Laboratory, Palu City, Central Sulawesi.

Test Organism
Tilapia (O. niloticus) sized 12.4±1.7g, obtained from the Central Fish Seed Center of Kalawara, Sigi Regency, Central Sulawesi were used in this research. The test fish were adapted to the media for 12 hours before implementation of the treatment.

Research Design
The study was designed using a completely randomized design (CRD). Three dosages of A. planci flour in the feed compared with one control deigned with: A); 7 %, B); 14 %, C); 21 %, and D; 0 % (control). Each treatment consisted of three replications.

Feed Formulation and Manufacturing
The research feed was formulated with a protein target of 28 %, and the same energy (Safir et al., 2017b). The composition of the use of feed raw materials is presented in Table 1. The manufacture of feed begins with weighing and mixing the ingredients, molding and drying the feed. The methods and procedures used refer to the research of Jiang et al. (2018). The prepared feed was confirmed for its nutrient content through proximate analysis using the  (2007). Total fat content was measured by the Soxhlet method and protein by the Kjedhal method. The water content was measured to calculate the difference in the weight of the feed before and after drying by heating method using an oven at 105 to 110 ºC for six hours (Takeuchi, 1988).

Maintenance of The Fish
A sample of twelve tilapia was put in an aquarium (50 x 25 x 30 cm 3 ) with a volume of 40 liters of water that had been prepared, Fish stocking at afternoon. Maintenance of test fish for 40 days with a frequency of feeding three times a day (morning, afternoon and evening) ad-libitum (Safir et al., 2017a). Before feeding, a shift pond was carried out in the aquarium and water was added to the amount of water that came out. To maintain water quality in the normal range, periodic monitoring is carried out. Water changes 2-3 times a week until the end of maintenance. Water quality measurements include temperature, pH and dissolved oxygen in the morning and evening before and after water changes.

Test Parameters and Data Analysis
Measurement of body weight of the test fish was carried out every 20 days by weighing all the test fish for each replication. The response of the treatments tested fish was observed through several observation parameters including daily growth rate (DGR), biomass increase (BI), feed consumption (FC) and feed conversion ratio (FCR) as well as the survival rate (SR) of each treatment. The data for the DGR, FCR and SR of the test fish were calculated by referring to the formula used by Jiang et al. (2018). BI is calculated by subtracting the final fish weight from the initial fish weight, the same thing for the value of feed consumption. The data obtained were tabulated using the Microsoft excel program and analyzed using the one-way ANOVA test at the level of 95%, and Duncan's test.

Growth Rate and Biomass Increase
The daily growth rate (DGR) and biomass increase (BI) of tilapia fed with different dosages of feed made from A. planci are presented in Table 2

Feed Consumption (FC) and Feed Conversion Ratio (FCR)
The  Table 2). Analysis of all treatments did not show any effect on the level of feed consumption and feed conversion ratio.

Survival Rate dan Water Quality
The percentage of survival rate of tilapia (O. niloticus) fed treated feed for 40 days ranged from 94.44 % -100 % (Figure 1). The analysis showed that there was no difference in the survival rate of the test fish for all treatments. The value of water quality during maintenance ranged from 25.1-28.3 °C temperature, 4.0-7.9 ppm dissolved oxygen and 7.4-8.3 pH.

Discussions
Tilapia fed a diet containing A. planci flour at 7 %, 14 % and 21 % did not show differences in growth between treatments including controls (P>0.05). The same results were found by Azlou, (2016) who tested feed made from A. planci on carp (Carassius auratus). The decrease in protein sourced from fish meal along with the decreasing use of this material, can be replaced by protein sourced from A. planci flour which is increasingly being used ( Table 1). Content of A. planci flour such as high protein is 29.69% (proximate analysis results) and can be absorbed by fish. Lou et al., (2011) reported that A. planci flour also contains 18 amino acids whose profile resembles that of fish meal. Of the 18 amino acids, there are 4 essential amino acids (leucine, valine, isoleucine, methionine) and 1 non-essential amino acid (cysteine) which have high values.
Leucine and isoleucine have functions as insulin protein simulators and regeneration of damaged cells. Valine plays a role in increasing endurance, lowering blood sugar levels and increasing growth (Bae et al., 2012;Han et al., 2014). Methionine plays an important role in metabolic processes in the body as well as a precursor of non-essential amino acids such as cysteine. Methionine and cysteine containing sulfur function as precursors of carnitine and glutathione to protect cells from oxidative stress (Fang et al., 2002;Li et al., 2007;Andri et al., 2020). A. planci also contains astaxanthin and saponins as antioxidants and anti-inflammatory (Mayer and Gustafson, 2008;Lou et al., 2011).
This strengthens the suspicion that the cause of growth performance including the consumption level and feed conversion ratio of the treated fish remained the same as the control fish even though the fish meal used was reduced. The use of fish meal in food composition therefore can be replaced by A. planci flour with no diffenences in fish growth between treated fish and control fish.
Furthermore, the consumption rate and feed conversion ratio were the same in all treatments with controls, indicating that the feed could be consumed and absorbed well by the fish. These conditions directly support the high survival rate of this study (Figure 1). One of the survival factors that remains high is the ability of organisms to absorb and utilize nutrients in feed for metabolic needs (Hamza, 2013).

Conclusions
The use of A. planci flour as a raw material did not have a negative effect on growth, consumption levels and feed conversion ratios and the survival of tilapia (O. niloticus). A. planci flour can be used up to 21 % as a raw material for protein sources in minimizing the use of fish meal.

Acknowledgment
Thanks to the Faculty of Animal Husbandry and Fisheries for funding from the 2021 Service Budget Implementation List, No. Contract; 442.b/UN28.2/PL/2021.