Due to the similar characteristics and living environment, the chemical composition and nutritional value of wild and cultured Indonesian T. soro were not significantly different.

This study used T. soro fish in consumable size. Wild T. soro was caught by fishermen from the Cipunagara River, Subang (West Java), Indonesia, in size of 36 ±3.6 cm in length and 535.5 ±24.2 g in weight (Figure 1). Identification was conducted by the Research Institute for Inland Water Fisheries. The 33.3 ±1.5 cm and 343.7 ±34.4 g cultured fish were from the Research Institute for Inland Water Fisheries’ ponds in Cijeruk, West Java, Indonesia. The cultured fish was fed with commercial feed (SINTA pakan ikan), composing of the protein content of 32%, fat content of 5%, dietary fiber of 6%, ash content of 12%, and moisture content of 12%. The feed was applied at 2% per day per total biomass since the fish attained a weight of 200 grams at 10 months. The fish was cultured with a stocking density of 15 fish per cubic running water. The fish was harvested at 10 months old.

The Chemical used in this study were Merck-based HCl, NaCl, HNO₃, NA₂SO₄, KOH, methanol, hexane, and isopropyl alcohol. Amino acid standard testing kit KG0-7167 and AG0-7184 (Phenomenex) were also used in this experiment.

The equipment used in this study were inductively coupled plasma optical emission spectrometry (ICP-OES) Agilent 720 (US), Gas Chromatography equipped with flame ionization detector (FID) (Perkin Elmer Technologies, US), centrifuge, microwave, vortex, oven, furnace, and freezer.

All analyses were conducted in triplicate. The results are reported as mean value ± standard deviation (SD). Differences between treatments for each parameter were tested for significance using t-test analysis.

The T. soro studied, both wild and cultured, were considered low-fat fish as the fat content of both was less than 2%. As shown in Table 1, except for fat, Ca, and Na, the proportions of all components were not different between wild and cultured T. soro (p >0.05). Wild T. soro contained higher Ca, Na, and fat contents than the cultured ones (p <0.05).

Studies on the proximate composition of wild and cultured fish of the same species have been conducted in many parts of the world. Inconsistent results in terms of the composition of the two groups were reported by different authors. Some reported that wild fish contained a higher content of certain chemical contents such as protein and fat, while others reported the opposite. Concerning protein content, wild fish were reported to be higher in the cases of yellow perch (Perca flavescens) (Gonzales et al. 2006), Nile tilapia (Oreochromis niloticus) (El-zaeem et al, 2012), and native fish Dormitator latifrons (López-Huerta et al., 2018). Contrary results were reported on freshwater giant prawn (Macrobrachium rosenbergii), shrimp (Penaeus monodon) (Islam et al., 2017), and sea bass (Dicentrarchus labrax) (Alasalvar et al., 2002), in which case the cultured ones were reported to have higher protein and fat contents compared to the wild sources. Feeds, habitats, seasons, and sex were the factors considered as most responsible. In fish culture, feeding is usually controlled for feed composition and feeding time to achieve certain targets such as weight, protein content, fat content, or color of the fish.

In this study, cultured T. soro were not significantly different from wild T. soro in moisture, protein, and ash content (p >0.05), but significantly different in fat content and minerals (p <0.05). Wild T. soro contained higher fat content and minerals compared to the cultured T. soro. This result was supported by previous studies conducted by Nettleton and Elmhurst (2000) and Job et al. (2015). Nettleton and Elmhurst (2000) found that among 3 fishes studied, the fat contents in cultured and wild rainbow trouts were not significantly different, while Job et al. (2015) found that the fat content of wild tilapia was higher than that of cultured tilapia. The cultured T. soro used in this study were harvested from ponds and were fed with 2% of total biomass per day of commercial feed (Kristanto, Asih and Winarlin, 2007). The commercial feed had a protein content of 32.70 ±0.34%, moisture of 9.47 ±0.01%, fat content of 7.76 ±0.16%, and ash content of 14.61 ±1.16%. Meanwhile, the wild T. soro harvested from the Cipunagara River, Subang (West Java, Indonesia) consumed natural feed available in the river water. Tor fish is reported to be an active swimmer, fast-moving fish which eats a variety of foods available in the river. This means that the river from where the T. soro were harvested might be rich in natural feed containing high-fat content, which was not only used as an energy source but also conserved in the body. The main diet of wild T. soro is algae, detritus, insects, or smaller fish (Haryono and Tjakrawidjaja, 2006). The study reported by Sarma et al. (2015) on the proximate composition of the Himalayan mahseer T. putitora showed comparable results with those of the warm water T. soro used in this study. Fat content is highly dependent on the species as well as fish ontogeny, feed, and environmental waters. In cold water environments, like Himalayas, the composition of fish was reported maximal during the monsoon season and lesser during the summer and winter seasons (Sharma and Singh, 2020).

The microelement (Zn) and macroelements (Ca, Na, K) in T. soro flesh were in general lower compared to those in golden mahseer (T. putitora) flesh, but the Fe contents of the two species were comparable. The T. soro studied, both wild and cultivated in ponds, were poor in micromineral selenium (Se) (Table 2). Microelement Se (selenium) was reported to be used as an important, and good, antioxidant against aluminum toxicity (Iordache et al., 2011). Himalayan mahseers, which live in the cold water of Himalaya, provide better sources of micro- and macroelement compared to T. soro which live in warm tropical water. However, compared to local fish Channa striata, T. soro was superior in terms of Ca, Na, Fe and comparable in terms of Zn and K contents. Therefore, T. soro, especially the wild ones, could be used as a good source of macrominerals. Potassium, calcium, and sodium are macrominerals essential to human health and involved in biological systems, while microminerals are involved in normal tissue metabolism and maintaining the health of the human body (Sharma and Singh, 2020). The results of this study are different from those of the study conducted by Gonzales et al. (2006), who reported that both cultured and wild Cichlasoma festae living in tropical Ecuadorian rivers did not have significantly different values for K, Zn, and Fe, but did have significantly different values for P, Ca, and Mg, with the cultured fish having the higher values.

The value of Fe in T. soro flesh was following FAO’s 2004 requirements for Fe content, that is, 0.23 – 2.1 mg.100g^-1 for human requirement (FAO, 2004). The macro- and micromineral contents in the fish were highly dependant on the water environment from where the fish is harvested, and this study supported earlier reports that different geographic areas influence the proximate composition and minerals in fish. Exogenous factors such as environment/geographic area from where the fish is harvested as well as indigenous factors such as species, age, and sex will affect the chemical composition of the fish, including minerals.

Table 2 shows the amino acid profiles of the cultured and wild T. soro, which indicate that the cultured fish had a higher amount than the wild ones. However, the amino acid patterns of both fish were similar. The orders of amino acids in terms of amount were not much different. The essential amino acids in T. soro flesh were mostly lysine and phenylalanine, with some addition of isoleucine and valine, while the non-essential amino acids were composed of allo- isoleucine as the most abundant as well as alanine, glycine, proline, and aspartic acid.

In general, fish is well known as a prime nutrition source with a high quality of proteins. The essential amino acid composition in the T. soro studied, both wild and cultured, was dominated by lysine, followed by phenylalanine, valine, and isoleucine. Lysine was also reported as the dominant amino acid in freshwater fish from Indonesia, namely, Channa striata and Osphronemus goramy (Chasanah et al., 2015; Susilowati, Sugiyono 2016). While Mohanty et al. (2014) reported lysine and aspartic acid as key amino acids in the freshwater fish harvested from cold water, the mahseer from Himalaya was reported to contain lysine and leucine and dominant amino acids. Even though the protein contents of T. soro and Himalayan mahseer (Tor putitora) were comparable, the concentrations of lysine and leucine were higher in Himalayan mahseer. As an essential amino acid, lysine plays an important role in human nutrition since this amino acid is required to obtain optimal growth. Hence, consumption of the fish can be used as one strategy to combat malnutrition and prevent stunting in children (Marinda et al., 2018; Ngaisyah and Rohman, 2019). In this study, nonessential amino acid allo-isoleucine (7.14 ± 0.18%) in the wild group and 10.46 ±0.26% in the cultured group) was dominant in T. soro, while the Himalayan mahseer flesh was dominated by glutamic acid, aspartic acid, and glycine. Allo-isoleucine was detected as a dominant amino acid in T. soro, but nonexistent in Tor putitora and other freshwater fish such as Channa striata (Table 2). Since it is non-essential, this amino acid could be formed from a precursor in the feed. On the contrary, leucine which is an essential amino acid was absent in the T. soro studied. Allo-isoleucine is branched-chain amino acids (BCAAs) required for muscle formation and proper growth, as are leucine, isoleucine, and valine. This BCAA was found low in chronic renal failure (CRF) patients on hemodialysis (Mohanty et al., 2014). Allo-isoleucine is associated with MSUD (Mapple syrup urinary disease) (Merriam-Webster, 2020), and it has been used as a pathognomonic marker of branched-chain keto acid dehydrogenase complex (BCKDC) disorders (Olson et al., 2014). Tor soro, both wild and cultured, are considered as sources of the functional amino acid (FAA) in human nutrition as it is rich in aspartic acid, glycine, proline, and glutamine. The non-essential amino acids glutamic acid, aspartic, and proline have participated in the healing process (Sarma et al., 2015). Aspartic acid regulates the secretion of important hormones and is the precursor of methionine, threonine, isoleucine, and lysine (Mohanty and Singh, 2018), while amino acid glycine is reported to be able to convert harmful materials in the body into harmless forms and to control gluconeogenesis and blood sugar. Meanwhile, glutamine plays an important role in regulating gene expression, intracellular protein turnover, nutrient metabolism, and oxidative defense (Mohanty et al., 2014; Wu, 2010).

Table 3 presents the fatty acid profile of T. soro. It shows that wild T. soro, in general, had higher fatty acids than those in the cultured ones, except arachidic acid (C20:0), eicosenoic acid (C20:1), EPA (C20:5), and linoleic acid (C18:2). The wild fish was richer in saturated fatty acid (SFA), while the cultured fish contained more monounsaturated fatty acid (MUFA) (p <0.05). The wild and cultured fish were not significantly different in PUFA, total n-3, n-6 contents (p >0.05), with similar patterns in the dominant fatty acids, i.e., oleic acid (C18:1 n9), palmitic acid (C16:0), linoleic acid (C18:2), DHA (C22:6), stearic acid (C18:0), and arachidonic acid (C20:4).

Polyunsaturated fatty acids (PUFAs), especially n-3, contribute positively to human health. Consumption of n-3 fatty acids has been reported to reduce the incidence of coronary heart diseases, depression, stroke, blood pressure disorders, glycemic index, triglycerides, and cancer (Taşbozan and Gökçe, 2017; Williams et al., 2017). Among n-3 fatty acids, docosahexaenoic acid (DHA) 22:6 n-3 and eicosapentaenoic acid (EPA) C20:5 n-3 correlate to good health benefits (Swanson et al., 2012; Mohanty and Singh, 2018). Our results show that wild and cultured T. soro had insignificant differences in total n-3, total n-6, DHA, and total PUFA, but cultured T. soro had higher EPA (eicosapentaenoic acid C20:5 n-3) compared to the wild one. The ratio of n-6 to n-3 in the fish studied was around 2, i.e., 1.99 ±0.06 and 2.17 ±0.13 for wild and cultured T. soro, respectively. The n-6/n-3 ratio of 1:5 is considered a good diet, but 1:2 is not harmful to human health (Ana et al., 2019).

The EPA and DHA contents of the fish were derived from the feed and their endogenous metabolism system. Being an omnivore, the wild T. soro derived the EPA and DHA from freshwater plankton and algae as natural feeds available in the river. On the other hand, the cultured T. soro consumed commercial feed. Consequently, the fatty acid profile of the fish was very dependent on the fatty acid in the feed. Commercial feeds are usually composed of a variety of alternative plant-based ingredients such as legume seeds, oilseed cakes, leaf meals, vegetable oils, and other materials. In the case of the cultured T. soro in this study, the feed consumed contained more EPA than those consumed by the wild ones. Although freshwater fish has been known not to be as good as marine fish at providing PUFA essential fatty acids, including n-3 fatty acids, this study showed that T. soro in both groups could be a better source of DHA than other freshwater fish such as Channa striata. DHA is a primary structural component of the human brain, cerebral cortex, skin, and retina (Swanson et al., 2012). Abouel-Yazeed (2013) reported that the fatty acid compositions of marine and freshwater fish species from Egypt were comparable, indicating that fresh water could be used as the source of polyunsaturated fatty acids (PUFAs). Meanwhile, Coutinho et al. (2019) reported that A. gigas, a freshwater fish from Brazil’s farm, was a great source of DHA (22:6 n-3) but had a low content of EPA (20:5 n-3). This agrees with Jaya-ram et al. (2018), who reported that the freshwater fish from Bukit Merah Reservoir contained considerable amounts of beneficial omega-3 PUFA, thus usable as a source of EPA and DHA.

The T. soro studied were rich in linoleic acid (C18:2 n-6), and this amino acid, along with α-linolenic acid (ALA C18:3 n-3), can be converted into the long-chain fatty acids EPA and DHA by freshwater fish body systems (Thilsted et al., 2014). The rates of conversion by endogenous metabolism are reported to vary between 1 and 10% by species (Robert et al., 2014; Williams et al., 2017). Therefore, it can be inferred that the essential fatty acids, EPA and DHA found in both groups studied were from either feed or endogenous conversion. Phytoplankton is the primary producer of these essential fatty acids. Therefore, besides diet, the fatty acid composition and another nutritional status of the fish will be ruled by many factors like species and environmental factors like salinity, temperature, seasons, geographical location, and weather, and this applies to both the farmed or wild fish (Robert et al., 2014; Williams et al., 2017; Sarma et al., 2015).