Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan (2022) 11(2): 111-116 DEPIK Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan Journal homepage: www.jurnal.unsyiah.ac.id/depik * Corresponding author. Email address: dianarachmawati1964@gmail.com p-ISSN 2089-7790; e-ISSN 2502-6194 Received 13 December 2021; Received in revised from 5 March 2022; Accepted 23 March 2022 Available online 26 June 2022 This is an open access article under the CC - BY 4.0 license (https://creativecommons.org/licenses/by/4.0/) Effect of dietary lysine on the growth performance of Pangasius hypophthalmus Diana Rachmawati 1, *, Dewi Nurhayati 1 1 Department of Aquaculture, Faculty of Fisheries and Marine Science, Diponegoro University, Semarang, Indonesia ARTICLE INFO ABSTRACT Keywords: Lysine Growth Feed Amino acid Pangasius hypophthalmus DOI: 10.13170/depik.11.2.23824 The success of intensive striped catfish (Pangasius hypophthalmus) cultivation requires quality feed that contains not only protein according to fish needs but also a complete essential amino acid profile to support the fish growth. One solution to overcome this problem is done through the addition of lysine in the feed commercial. This study aimed to examine the effect of lysine addition on the efficiency of feed utilization, growth and body composition of P. hypophthalmus. The study consisted of 4 (four) treatments those were with dosages of 0% / kg of feed (A); 0.6% / kg of feed (B); 1.2% / kg of feed (C); and 2.4% / kg of feed (D) of lysine for every kg of feed. The experimental diet in this study was a commercial feed in the form of pellets which was added with the lysine. Fixed feeding rate of 5%/weight of biomass/day was applied at frequency 3 times a day. The experimental fish used were P. hypophthalmus fingerling has an average weight of 4.13 ± 0.26 g/individuals. The results showed that the addition 1,2% / kg of lysine to the diet increased SGR, EFU, FCR, PER and protein content of body composition of P. hypophthalmus. Introduction Striped Catfish (Pangasius hypophthalmus) is one of freshwater species that is very popular and widely consumed by the people of Indonesia ( Rachmawati and Prihanto, 2019). P. hypophthalmus production in 2019 was 384,310 tons, fourth after catfish, tilapia, and goldfish (KKP, 2022). In the intensive cultivation of P. hypophthalmus, quality feed is required. Basically, quality feed does not only contain protein according to fish requirements but also must complete essential amino acids to support growth performance of fish. Fish require ten essential amino acids, which are indispensable in feed for maximum growth (Ahmed and Khan, 2004). However, it expected that commercial artificial diets are lack of lysine due to insufficient amount of lysine in plant- based protein source ingredients ( Mai et al., 2006; Gatlin et al., 2007). One solution to overcome this problem is by supplementing lysine in dietary feed. Farhat and Khan (2013) found that lysine is an essential amino acid that the body cannot produced. Therefore, the addition of amino acids in fish feed supplements is required as an effort to increase growth. According to NRC (2011), lysine is an amino acid required by fish because lysine is found in the highest concentration in most fish species. Lysine is indispensable for growth, normal physiological function and protein synthesis ( Robinson et al., 2001). Walton et al. (1984) suggested that lysine and methionine play a role in the synthesis of carnitine which functions in the transportation of fatty acids to produce energy through oxidation. Nguyen et al. (2013) mentioned that the addition of lysine in feed can reduce the body fat content of fish, and increase protein retention (Cao et al., 2012) besides playing a role in metabolism for muscle growth (Khan and Abidi, 2011). The addition of lysine in fish diet allows faster metabolic processes compared to the addition of other amino acids (Farhat and Khan, 2013). Many researches were done related to lysine in the diet of several fish species, namely Penaeus monodon (Biswas et al., 2006), Macrobrachium rosenbergii (Pramana et al.,