Enhancing the productivity performance of Cyprinus carpio L. by Manihot utilissima Pohl. leaves supplementation

Cyprinus carpio is an economically crucial freshwater commodity in Indonesia and across the globe. Fish demand has a rising trend, which not in line with productivity. Innovation and aspects of food safety are the primary keys to increasing productive capacity. Therefore, the utilization of Manihot utilissima leaves as an alternative to improve national fish's productivity rate is a worthy consideration. They have multiple nutrients, including protein and fat needed by C. carpio seeds. This study aims to determine the optimal dose of M. utilissima supplementation to increase the productivity of C. carpio seeds. The methodology consisted of four treatments (0.5 mL/250 g, 10 mL/250 g, 15 mL/250 g) with four replications for 21 days. The outcome showed that P4 treatment (15 mL) could increase the relative growth rate by 21.10%/day, and it decreased the feed conversion ratio by 0.84. However, there is no significant effect on the survival rate. The study concludes that P4 treatment (15 mL) has positively increased the relative growth rate of C. carpio, and decreased its feed conversion ratio.


INTRODUCTION
Cyprinus carpio L. is a freshwater commodity that has an important economic value in Indonesia and across the globe. Its productivity in Indonesia continues to increase by reaching 8.92% in 2019, with a total production value of 785.800 tons (Ministry of Agriculture Republic Indonesia, 2015). However, the demand for C. carpio L. shows an increasing trend but not in line with its productivity rate. Some factors that should be considered in aquaculture activity consisted of water quality (Davidson et al., 2013;Tallar & Suen, 2016), disease (Stentiford et al., 2012;Stentiford et al., 2017), microalgae-bacteria interactions (Natrah et al., 2014), biosecure (Bhowmick & Crumlish, 2016;Hasimuna et al., 2020), and nutrition ( (Mente et al., 2011;Belton et al., 2014;Ekasari et al., 2016). Moreover, the use of antibiotics as disease control in aquaculture may pose a negative impact on human health, since antibiotics can leave residues in aquatic organisms that are harmful to world food security (Li et al., 2006;Zhang et al., 2014). Therefore, alternative antibiotic substances can come from plants that have the potential to be utilized in aquaculture activity (Citarasu, 2010;Hai, 2015).
Immunostimulant plant-based materials such as seaweed, probiotics, and fungi contain anti-microbial effects that can improve product performance and immune system in aquaculture (Efianda et al., 2018;Ramadhani et al., 2019;Rudi et al., 2019). Immunostimulant material derived from plants is relatively easy to handle, and it poses no pollution toward the environment, thus it is recommended for cultivation activity in the long term (Panda et al., 2012;Munaeni et al., 2020). One particular ingredient to be used to increase productivity growth is the leaves of Manihot utilissima Pohl. The leaves contain 29% of protein, 19.06% of crude fibre, 9.41% of fat, 8.83% of ash (Iheukwumere et al., 2008). Further, feed containing micro and macronutrients can increase the energy needed to increase growth and feed efficiency in carp (Syafar et al., 2017). The additional use of M. utilissima leaves for feeding purposes is viewed as an effort to meet the needs of proper nutrition as well as to enhance the immune system of C. carpio without a costly budget. The fact that limited TEUKU REZA EFIANDA et al.

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information is available regarding the utilization of M. utilissima as a supplement in C. carpio feed has prompted this study. Therefore, its use as a supplementary feed needs to be developed for a wide application by fish farmers throughout Indonesia. The purpose of this study was to determine the optimal dosage of M. utilissima leaves as supplementary feed to improve the productivity performance of C. carpio.

MATERIALS AND METHODS
Supplementation preparation. The experimental design was carried out with four treatments and four replications for 21 days of maintenance. Manihot utilissima Pohl. leaves were prepared and washed thoroughly then dried in the open air, then mashed using a blender with a mixture of a small amount of water (50 mL). Extraction result was applied for supplementation in feeds with doses of P1 (0 mL/250 g), P2 (5 mL/250 g), P3 (10 mL/250 g), and P4 (15 mL/250 g). Feed composition included feed size by 0.7 mm, protein by 40%, lipid by 5%, fibres by 4%, and water content by 10% (Matahari Sakti PF500 brand).
Culture Preparation. Square containers were placed in a pool with an area of 2 x1 m with a water level of 50 cm. Some 160 test fish were measured by 3-5 cm and were acclimatized for two days before the practical research. Ad libitum feeding method with a frequency interval of 08.00 a.m., 13.00 p.m. and 18.00 p.m., respectively. The feed conversion ratio was measured using the formula FCR = F / Bt FCR= Feed conversion ratio F= Amount of fish feed given during research (g) Bt= Fish biomass at the end of the research (g) Data analysis. Quantitative data were analyzed with an ANOVA (analysis of variance) 95% confidence interval, and qualitative data were presented descriptively.

RESULT AND DISCUSSION
The observations showed that supplementation of Manihot utilissima Pohl. leaves can significantly affect the production performance of Cyprinus carpio L. seeds with a maintenance period of 21 days in ponds. The results are presented in figure 1. The statistical analysis showed that there is no significant impact on the survival rate from the use of M. utilissima leaf supplementation.
The condition showed that the pond water quality environment during the study was in optimal condition. Water quality is the main factor that must be considered for survival rate during aquaculture (Zhang et al., 2011;Estim et al., 2019). The survival rate of fish affects the environmental conditions so that fish can adapt optimally, and there is no disruption to disease attacks. Further, the success of aquaculture is influenced by both internal and external factors of the fish. The genetics of the breeders predominantly influences internal factor since they are related to the immune system against disease. In contrast, external factors are influenced by the quality of feed and optimal water quality in each species of fish. The use of M. utilissima leaves as supplementation significantly affected the relative growth of C. carpio seeds, where the best result came from P4 treatment (15 mL) by reaching 21.10%/day rather than P1 (control) 12.37%/day (Figure 2). Vitamin C and carbohydrates contained in the leaves of Manihot utilissima had a positive influence on the rate of growth of C. carpio seeds cultivated in the ponds. Iheukwumere et al. (2008) mentioned that M. utilissima leaves contain micronutrients and macronutrients such as vitamins, iron, protein, and carbohydrates that can improve nutrition in organisms. The absorption of nutrients in fish affects its digestive system so that growth patterns and body weight can increase ((Rašković et al., 2011;Rachmawati & Samidjan, 2013;Rønnestad et al., 2013). The appropriate texture and attractants of the feed also affect the growth patterns for each species, making it more effective for spurring growth in fish (Dani et al., 2005). Besides, giving immunostimulants to fish will affect the immune system so that growth is enhanced (Yusuf et al., 2015). C. carpio is a herbivore that requires vegetable intake in its feed, since the addition of M. utilissima leaves supplementation have a significant effect on a a a a their growth and reduce feed conversion ratio. Khairul & Hasan (2018) states that systematic and controlled feeding practices can increase the level of fish consumption, hence fish growth continue to increase.
Supplementation with M. utilissima leaves can significantly reduce the feed conversion ratio of C. carpio seed (Figure 3). The best result was obtained with P4 treatment with 0.84 rather than control 1.39. M. utilissima leaves supplementation has a role in growth, metabolism, and as a source of energy which increases fish growth and reduced feed costs. Immunostimulant properties of M. utilissima leaves affects the surface structure of the fish intestine. Thus, the intake of nutrients can be absorbed well, even with the low amount of feed consumed, the growth rate continues to increase. Efianda et al. (2018) mentioned that the supply of natural immunostimulant ingredients affects the structure of the intestinal surface of microvilli to become denser, thereby increasing growth and decreasing feed conversion ratio in aquatic organisms. Also, the effect of additional protein from Manihot utilissima leaves provides a significant effect on the efficiency of feed given during the study. Setiawati et al. (2008) stated that protein content in the feed is a major factor in aquaculture affecting feed growth and feed efficiency. The supplementation process of M. utilissima to C. carpio during its 21-days of conservation showed that the water quality was in the optimal range (Table 1). National Standardization Agency of Indonesia (2016) mentions optimal water quality factors, i.e. temperature ranges from 25 to 30°C, pH ranges from 6.5 to 8.5, DO above 5 mg/L and ammonia below 0.01 mg/L. In fact, environmental conditions will affect the growth and survival rate of C. carpio. Therefore, poor water quality can increase mortality and losses to farmers. Water quality must be maintained according to the optimal range for each species of aquatic organism.
Ammonia level is an indicator of water quality in fish farming, high levels of ammonia can negatively affect the growth and survival of carp. According to Prianggara et al. (2016) mentioned ammonia levels could cause stress and tissue damage in fish. Besides, the ammonia toxicity levels can accelerate the growth of aquatic plants and increase the number of algae that can cause eutrophication in aquaculture ponds. Further, the content of pH and dissolved oxygen are interrelated, as indicated if the pH is alkaline then the condition of dissolved oxygen has decreased, as well as the opposite condition if dissolved oxygen is high then the pH will be acidic. Furthermore, the conversion of ammonia to nitrate is influenced by stable dissolved oxygen (Cema et al., 2011;Xie et al., 2013;Azhari & Tomasoa, 2018). Therefore, the parameters of water quality are interrelated as a major factor in the growth of fish.

CONCLUSION
The result of 15 mL supplementation Manihot utilissima has a positive effect on the fish relative growth rate, and feed conversion ratio of Cyprinus carpio. Water quality during research was in the optimal range for Cyprinus carpio.