Feed intake and gene expression of appetite-regulating hormones in Salminus brasiliensis fed diets containing soy protein concentrate (2023)


Golden (Salmon from BrazilCharaciformes: Salmininae) is a large predatory fish native to South America (Flora et al., 2010), which has high commercial value. Due to the reduction of natural stocks and consequent limitation of commercial fishing, and due to its rapid growth, the dorado has attracted the attention of aquaculture companies (Rosa and Lima, 2008; Ribeiro and Portella, 2020). The feeding habits of the dorado, a strictly carnivorous fish, represent a great challenge for breeding and rearing, as the species requires expensive and high protein fishmeal (FM) feeds with sufficient amino acid profiles to achieve proper development and growth. (Fracalossi et al., 2004; Dairiki et al., 2013).

The growing demand for FM from the expanding aquaculture business, combined with the constant reduction of feedstock from fisheries bycatch (FAO, 2020), has led fish farmers to seek replacement of FM with less expensive and highly available (Hua et al., 2019). While FM remains an important ingredient in the larval and juvenile stages of cultured fish, lower levels are currently used in later stages of growth (Naylor et al., 2021). Despite their potential as a substitute for animal protein in aquatic feeds, plant proteins may be of limited use for carnivorous fish (Zhou et al., 2018) as they contain antinutritional factors and inadequate amino acid profiles (Pelletier et al., 2018) . To overcome the limitations of plant protein sources, extraction of non-protein components from plant-derived ingredients can result in concentrated products with high levels of protein (Xie and Jokumsen, 1997; Akharume et al., 2021). Soy protein concentrate (SPC), obtained by extracting carbohydrates and lipid fractions from soybean meal, is a promising source of vegetable protein to replace animal protein in aquatic feeds (Dersjant-Li, 2002; Gatlin et al., 2007). Although SPC is relatively low in essential amino acids (EAA), especially methionine and cysteine, it has low levels of antinutritional components (Storebakken et al., 2000; Dersjant-Li, 2002; NRC, 2011), is readily available in large quantities, and it has a low price compared to FM (Pezzato et al., 2002; Ray Gyan et al., 2019).

Several studies have been carried out on the use of SPC in the feeding of some species of aquaculture fish, including white sea bass,Centropomus viridis(Arriaga-Hernandez et al., 2021), Atlantic salmon (salmo salar) (Hartviksen et al., 2014), peito de ouroSparus aurata(Kissil et al., 2000), rainbow trout (Oncorhynchus mykiss) (Kaushik et al., 1995), to golden (Pagrus major) (Tola et al., 2019a) and yellow croakerLarimichthys crocea(Wang et al., 2017). Although fish tolerance to dietary SPC varies according to the species used as a model (Chen et al., 2019), 40 to 100% of the FM dietary protein can often be replaced by SPC without negative impact on fish growth performance. fish (Dersjant-Lee, 2002).

Replacing FM and fish oil with plant sources may affect fish health by altering their immune function and endocrine systems (Martin and Krol, 2017; Simo-Mirabet et al., 2018; Naylor et al., 2021), leading to to the development of disease and stress and subsequent reductions in feed intake and growth and production losses (Naylor et al., 2021). Improving voluntary feed intake is therefore a decisive step in optimizing fish growth and survival.

Food intake is regulated by hormones that either stimulate (orexigenic) or inhibit (anorexigenic) consumption in both mammals (Parker and Bloom, 2012) and fish (Volkoff, 2016). These appetite-regulating peptides are produced both in the brain and in peripheral tissues such as the gastrointestinal tract, and regulate food intake and digestive functions (Ronnestad et al., 2017; Soengas et al., 2018). Among the stimulants are orexin, and among the inhibitors cocaine and amphetamine-regulated transcript (CART), cholecystokinin (CCK), peptide YY (PYY) and leptin (Volkoff, 2016; Soengas et al., 2018;). Many of these hormones respond to the composition of diets and regulate energy homeostasis, ensuring optimal food intake, digestion and absorption of nutrients (Bertucci et al., 2019). Very little is known about how plant-based diets, especially SPC, affect feeding and appetite-regulating hormones in fish, as few species have been studied [p.Piaractus in Mesopotamia) (Volkoff et al., 2017); tambaqui (Colossoma macropomum) (Martins et al. Correa et al., 2020); Tilapia do Nilo (Oreochromis niloticus) (Ribeiro et al., 2016)].

This study aimed to evaluate the effects of graded levels (zero to 100%) of SPC replacing FM as a dietary protein source on feed intake and relative levels of transcribed gene expression of hormones that control feed intake. and digestion in golden chicks. The results of this study provide new insights into the development of plant-based protein diets that can maintain and enhance fish growth, health and well-being, promote the profitability and sustainability of aquaculture practices, as well as shed light on on the effects of dietary protein composition. in the regulation of appetite in carnivorous fish.

section extract

Materials and methods

Forsøg blev udført på Fish Nutrition Laboratory, Department of Animal Science, Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ), University of São Paulo (USP) and Piracicaba (SP, Brasilien; 22)°42′ 25” S, 47°38′ 29” W) (Fish Nutrition Laboratory, Department of Animal Science, Luiz de Queiroz College of Agriculture, University of São Paulo). The experimental procedures followed the guidelines of the ethical principles in animal experimentation of the Brazilian College of

Effects of dietary soy protein concentrate on feed intake

Daily feed intake was higher in groups fed 0% and 25% SPC compared to the other treatments. Fish fed 50% and 75% SPC had a daily intake of approx. 20% lower than for fish fed 0% and 25% SPC. Fish fed the 100% SPC diet had lower feed intake than all other groups (Fig. 1).


CCK expression levels in the foregut were higher in the groups fed 0%, 25% and 50% SPC compared to the fish fed 100% SPC. No differences were observed between fish fed 75% SPC and any of the other groups (Fig.


Several studies have investigated the effects of inclusion levels of SPC or other vegetable protein sources in fish feeds, but only a few studies [p. (Volkoff et al., 2017)] addressed the effects of 100% plant-based diets (restriction of crude protein content to an exclusively vegetable source of protein) on fish feeding and nutrition. This study evaluated feed intake and expression of appetite-regulating hormones in the intestine, pyloric cecum and hypothalamus of freshwater carnivorous fish fed diets

Declaration of competing interest

The authors declare no conflict of interest.


This work was supported by aSão Paulo Research Foundation (FAPESP)scholarship for R.E. Sabioni (grant #2015/23796-0) it is aNatural Sciences and Engineering Research Council (NSERC) Discovery Award(DG, grant number261414-03) for H. Volkoff. The authors would like to thank the company “CJ Selecta” for supplying the soy protein concentrate used in this research.

Recommended Articles (6)

  • Research Article

    Hyaluronic acid metabolism during early development in the Japanese eel, Anguilla japonica

    Comparative Biochemistry and Physiology, Part A: Molecular and Integrative Physiology, Volume 268, 2022, Article 111203

    Hyaluronic acids (hyaluronans, HAs) are glycosaminoglycans produced in the body of Anguilliforme and Elopiforme leptocephali, and HA is believed to serve as a source of metabolic energy in planktonic life stages. To investigate this hypothesis, we investigated the dynamics of HA during early Japanese eel growth (Anguilla japonica), including during metamorphosis. From histochemical observations in fully developed leptocephalus, HA occupied approx. 40-50% of the cross-sectional area, and muscle tissue occupied less than 20%. However, HA and water content reach a maximum during leptocephalus, decreasing during metamorphosis. We found that during leptocephalus, HA actively accumulates in the body and plays a role in specific density adjustment, facilitating planktonic life. It was thought that after metamorphosis, HA's role in facilitating flow would cease and it would be metabolized to glucose and/or triglycerides.

  • Research Article

    Elevated plasma leptin levels of fasting rainbow trout decline rapidly in response to feed intake

    General and Comparative Endocrinology, Volume 214, 2015, pp. 24-29

    Leptin has an anorectic effect in fish, indicating a role in regulating growth and energy homeostasis. The study aimed to further elucidate the physiological role of leptin in rainbow trout, specifically its short-term response to food intake after a period of fasting. Using a salmon leptin radioimmunoassay, the study demonstrates differences in plasma leptin levels in fish with different nutritional status and at the beginning of feeding. Some of the fasted fish were clearly in a state of anorexia and did not start feeding during the 72 hours of refeeding. For fish that initiated feeding, both previously fed and fasted, plasma leptin levels rapidly decreased during the first 24 hours in association with increasing amount of food reaching the gastrointestinal tract, whereas individuals that did not feed maintained a high plasma level of leptin. The data indicate that the anorectic state induced by leptin is interrupted after the initiation of feeding and that the regulatory mechanisms that lead to the decrease in plasma leptin levels are linked to nutrient levels.

  • Research Article

    Cloning, tissue distribution and effects of fasting on leptin and ghrelin mRNA expression levels in red-bellied piranha (Pygocentrus nattereri)

    General and Comparative Endocrinology, Volume 217-218, 2015, pp. 20-27

    cDNAs encoding the appetite-regulating peptides leptin and ghrelin were isolated from the red-bellied piranha (Characiformes, Serrasalmidae) and their tissue and brain mRNA distributions were investigated. Compared to other fish, the sequences obtained for all peptides were more similar to sequences from other Characiformes and Siluriformes fish. All peptides were widely expressed in the brain and in various peripheral tissues, including the gastrointestinal tract. To better understand the role of these peptides in regulating red-bellied piranha feeding, mRNA expression levels of leptin and ghrelin were examined in the brain and gut, in fed and 7-day fasted fish. No significant difference in expression was observed across the brain for any of the peptides. In the intestine, there was a decrease in leptin mRNA expression and an increase in ghrelin mRNA expression in fasted compared to fed fish. The results suggest that leptin and ghrelin may play an important role in feeding regulation and energy homeostasis in the red-bellied piranha, and this role may be more prominent in the gut than in the brain.

  • Research Article

    Appetite-regulating peptides in the red-bellied piranha, Pygocentrus nattereri: Cloning, tissue distribution, and effect of fasting on mRNA expression levels

    Peptides, Volume 56, 2014, pp. 116-124

    cDNAs encoding appetite-regulating peptides apelin, cocaine and amphetamine-regulated transcription (CART), cholecystokinin (CCK), peptide YY (PYY) and orexin were isolated from red-bellied piranhas, and their mRNA distributions in tissue and brain were investigated. Compared to other fish, the sequences obtained for all peptides were more similar to sequences from other Characiformes as well as Cypriniformes fish. All peptides were widely expressed in the brain and in various peripheral tissues, including the gastrointestinal tract. To assess the role of these peptides in regulating red-bellied piranha feeding, we compared brain mRNA expression levels of these peptides, as well as intestinal mRNA expression of CCK and PYY, between fish fed and fasted for 7 days. In the brain, fasting induced a significant increase in apelin and orexin mRNA expression and a decrease in CART mRNA expression, but there were no significant differences in brain PYY or CCK mRNA expression between fed and fasted fish. In the intestine, PYY mRNA expression was lower in fasted compared to fed fish, but there was no significant difference for intestinal CCK mRNA expression between fed and fasted fish. Our results suggest that these peptides, perhaps with the exception of CCK, play an important role in the regulation of red-bellied piranha feeding.

  • Research Article

    Nutrition and reproduction in fish

    Encyclopedia of Reproduction, binding 6, 2018, s. 743-748

    Proper nutrition is essential for successful fish reproduction. Reduced food availability or poor quality food such as nutrient imbalances such as lipids, proteins, sugars, vitamins and minerals can have a negative impact on all stages of reproduction including normal development and puberty in immature fish, production and release of gametes and reproductive behavior.

  • Research Article

    In vitro evaluation of interactions between appetite-regulating peptides in the brain of goldfish (Carassius auratus)

    Peptides, Volume 61, 2014, pp. 61-68

    Orexins, apelin, melanin-concentrating hormone (MCH), neuropeptide Y (NPY) and cocaine and amphetamine-regulated transcription (CART) are important appetite-regulating factors produced by the brain in mammals and fish. These peptide systems and their target sites are widely distributed in the central nervous system. Although morphological connections between some of these systems have been demonstrated in the brain, little is known about the functional interactions between these systems, particularly in fish. To better understand the interactions between appetite-related peptides, the effects ofin vitrotreatments of the hindbrain, forebrain and hypothalamus - an important regulatory area of ​​feeding - fragments with MCH, apelin and orexin on the expression of MCH, apelin, orexin, CART (form 1 and 2) and NPY were evaluated. Overall, the apelin and orexin systems stimulate each other and stimulate the NPY system while inhibiting the CART system, which is consistent with the known orexigenic effects of these two peptides. The effects of MCH remain unclear: although it appears to interact positively with orexigenic systems - as it stimulates the orexin and apelin systems and its expression is increased by apelin - it also increases hypothalamic expression of CART2 - but not CART1 - an anorexic factor, and inhibits the system NPY in all brain regions examined. This study suggests that MCH, apelin, orexin, CART and NPY interact in the goldfish brain and that these interactions may vary in nature and strength according to the peptide form and the brain region considered.

© 2022 Elsevier Inc. All rights reserved.

Top Articles
Latest Posts
Article information

Author: Maia Crooks Jr

Last Updated: 04/22/2023

Views: 6035

Rating: 4.2 / 5 (43 voted)

Reviews: 82% of readers found this page helpful

Author information

Name: Maia Crooks Jr

Birthday: 1997-09-21

Address: 93119 Joseph Street, Peggyfurt, NC 11582

Phone: +2983088926881

Job: Principal Design Liaison

Hobby: Web surfing, Skiing, role-playing games, Sketching, Polo, Sewing, Genealogy

Introduction: My name is Maia Crooks Jr, I am a homely, joyous, shiny, successful, hilarious, thoughtful, joyous person who loves writing and wants to share my knowledge and understanding with you.