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Vitamin D3 is believed to be a contributing factor to innate immunity. Vitamin D receptor (VDR) has a positive effect on inhibiting nuclear factor κB (NF-κB)-mediated inflammation. The underlying molecular mechanisms remain unclear, particularly in mollusks. Consequently, this study will investigate the process of vitamin D3/VDR regulating NF-κB pathway and further explore their functions on inflammation, autophagy, and apoptosis in abalone Haliotis discus hannai. Results showed that knockdown of VDR by using siRNA and dsRNA of VDR in vitro and in vivo led to more intense response of NF-κB signaling to lipopolysaccharide and higher level of apoptosis and autophagy. In addition, 1,25(OH)2D3 stimulation after VDR silencing could partially alleviate apoptosis and induce autophagy. Overexpression of VDR restricted the K48-polyubiquitin chain-dependent inhibitor of κB (IκB) ubiquitination and apoptosis-associated speck-like protein containing CARD (ASC) oligomerization. Besides, VDR silencing resulted in increase of ASC speck formation. In further mechanistic studies, we showed that VDR can directly bind to IκB and IKK1 in vitro and in vivo. In the feeding trial, H&E staining, TUNEL, and electron microscope results showed that vitamin D3 deficiency (0 IU/kg) could recruit more basophilic cells and increase more TUNEL-positive apoptotic cells and lipid droplets (LDs) than vitamin D3 supplement (1000 IU/kg and 5000 IU/kg). In summary, abalone VDR plays a negative regulator role in NF-κB-mediated inflammation via interacting with IκB and inhibiting ubiquitin-dependent degradation of IκB. Vitamin D3 in combination with VDR is essential to establish a delicate balance between autophagy and apoptosis in response to inflammation. [ABSTRACT FROM AUTHOR]

This study was aimed at evaluating whether dietary chromium yeast (CrYst) and astaxanthin (ASTA) could enhance the growth performance, anti-oxidative capacity, and resistance to heat stress of abalone Haliotis discus hannai (initial body weight: 1.14±0.10 g; initial shell length: 19.20±0.87 mm) after a 120-day feeding trial. Based on the basal diet, the other three experimental diets were designed with supplementation of 2 mg/kg of CrYst, 80 mg/kg of ASTA, and 2 mg/kg of CrYst + 80 mg/kg of ASTA, respectively. The results showed that supplementation of 2 mg/kg of dietary CrYst significantly increased weight gain rate and the daily increment in shell length of abalone (P < 0.05). However, 80 mg/kg of dietary astaxanthin supplementation had no significant effects on the growth (P > 0.05). Meanwhile, there were no significant differences in feed intake and feed conversion ratio among all the groups (P > 0.05). Meanwhile, adding 2 mg/kg of CrYst and/or 80 mg/kg of ASTA into the diet improved the anti-oxidative capacity in serum and hepatopancreas, increased the gene expression of hsp70 and hsp90 in the hepatopancreas, and reduced the cumulative mortality and falling rate of abalone during the heat stress. In conclusion, dietary supplementation of CrYst and/or ASTA had positive effects on growth and anti-stress of abalone. [ABSTRACT FROM AUTHOR]

A 120-day feeding trial was conducted to investigate the effects of relative higher and lower dietary protein levels on the growth, immunity and anti-stress of abalone Haliotis discus hannai fed diets with 17.64% (low), 30.49% (normal) and 43.27% (high) of proteins, respectively. The results showed that compared with 30.49% of dietary protein, 17.64% and 43.27% of dietary protein levels significantly decreased the weight gain rate and the activities of α-amylase, trypsin, alanine aminotransferase and aspartate aminotransferase in the hepatopancreas and serum of abalone (P < 0.05). Abalone fed 30.49% of dietary protein had the highest activity of superoxidase, acid phosphatase, alkaline phosphatase, lysozyme and the total anti-oxidative capacity, and the lowest content of malondialdehyde in the serum and hepatopancreas (P < 0.05). The gene expressions of TOR, S6k, Bcl-2, IκB, NfκB, TNF-α and Nrf 2 were significantly up-regulated in the group with 30.49% of dietary protein (P < 0.05). Pathological abnormalities in hepatocyte cells of abalone were found in the groups with 17.64% and 43.27% of dietary protein. Meanwhile, accumulative mortalities of abalone after the Vibrio parahaemolyticus challenge test and heat stress test were significantly increased within these two groups (P < 0.05). In conclusion, the excessive (43.27) or deficient (17.64) dietary protein levels depressed the growth and immunity of abalone. Combined with the stress tests results, 17.63% or 43.27% of dietary protein contents are not recommended to the abalone facing the stress of vibriosis or high-water temperature (≥28 °C). • Abalones were fed diets with 17.64% (low), 30.49% (normal) and 43.27% (high) of proteins, respectively, for 120 days. • Relative low or high dietary protein contents decreased the growth of abalone. • Normal dietary protein had the higher anti-oxidation and immune related enzyme activities and TOR expressions. • 17.63% or 43.27% of dietary protein contents are not recommended to the abalone facing the environmental stress. [ABSTRACT FROM AUTHOR]

A 115‐day feeding trial and subsequently a 10‐day challenge test with Vibrio parahaemolyticus were conducted to investigate the effects of dietary antimicrobial peptide APSH‐07 on growth performance, immune response, antioxidative status and vibriosis resistance of abalone Haliotis discus hannai (initial body weight: 2.06 ± 0.01 g; initial shell length: 25.42 ± 0.18 mm). Four artificial diets were designed with 0 (artificial diet control), 7.5, 15.0 and 22.5 mg/kg of APSH‐07, respectively. The brown alga Laminaria japonica was used as the live food control. Results showed that the specific growth rates of abalone in the groups with 7.5 and 15.0 mg/kg dietary APSH‐07 were significantly higher than those in the controls (p <.05). The total haemocyte counts and respiratory burst activity in haemolymph of abalone in the group with 7.5 mg/kg of dietary APSH‐07 were significantly higher than those in the groups with 0 and 22.5 mg/kg of dietary APSH‐07 (p <.05). The gene expression levels of Mn‐superoxide dismutase and thioredoxin peroxidase 2, and the activities of glutathione peroxidase in the group with 7.5 mg/kg of dietary APSH‐07 were significantly higher than those in the other groups (p <.05). Cumulative mortality of abalone after the challenge test was significantly decreased in the group with 7.5 mg/kg of dietary APSH‐07 supplementation. Supplementation of 22.5 mg/kg dietary APSH‐07 significantly increased the cumulative mortality. In conclusion, 7.5 mg/kg of dietary APSH‐07 supplementation had the better growth performance, higher antioxidation, immune and disease resistance capacity of abalone. Excessive supplementation of dietary antimicrobial peptide APSH‐07 (22.5 mg/kg) had significantly negative effects. Further studies are needed to determine the optimal level of dietary APSH‐07 supplementation for abalone. [ABSTRACT FROM AUTHOR]

Abstract: This study was conducted to investigate protective effects of dietary selenium (Se) on abalone Haliotis discus hannai Ino against the toxicity of cadmium (Cd). A 60‐day feeding trial was conducted with abalone (initial weight: 3.17 ± 0.01 g), which were exposed to 0.34 mg/L of waterborne Cd. During a feeding trial, abalone were fed graded levels of Se at 0.10 (controls), 1.31, and 4.20 mg/kg diet respectively. Results showed that there was no significant difference in specific growth rate and survival rate of abalone among the three treatments. Compared with the controls, dietary Se significantly decreased Cd concentrations in serum, muscle, mantle, gill, mantle, and hepatopancreas of abalone. Besides, compared with the controls, dietary Se significantly increased metallothionein concentration in the hepatopancreas of abalone. Additionally, compared with the controls, dietary Se significantly decreased concentrations of malondiadehyde and protein carbonyl in hepatopancreas of abalone. Meanwhile, compared with the controls, dietary Se significantly increased activities of glutathione peroxidase, thioredoxin reductase, and thioredoxin peroxidase, and concentration of glutathione in the hepatopancreas of abalone. Based on the data above, in abalone, dietary Se showed protective effects against waterborne Cd. [ABSTRACT FROM AUTHOR]

Arginine plays an important role in the regulation of the target of the rapamycin (TOR) signaling pathway, and Solute Carrier Family 38 Member 9 (SLC38A9) was identified to participate in the amino acid-dependent activation of TOR in humans. However, the regulations of arginine on the TOR signaling pathway in abalone are still unclear. In this study, slc38a9 of abalone was cloned, and the slc38a9 was knocked down and overexpressed to explore its function in the regulation of the TOR signaling pathway. The results showed that knockdown of slc38a9 decreased the expression of tor, ribosomal s6 protein kinase (s6k) and eukaryotic translation initiation factor 4e (eif4e) and inhibited the activation of the TOR signaling pathway by arginine. Overexpression of slc38a9 up-regulated the expression of TOR-related genes. In addition, hemocytes of abalone were treated with 0, 0.2, 0.5, 1, 2 and 4 mmol/L of arginine, and abalones were fed diets with 1.17%, 1.68% and 3.43% of arginine, respectively, for 120 days. Supplementation of arginine (0.5–4 mmol/L) increased the expressions of slc38a9, tor, s6k and eif4e in hemocytes, and abalone fed with 1.68% of dietary arginine showed higher mRNA levels of slc38a9, tor, s6k and eif4e and phosphorylation levels of TOR, S6 and 4E-BP. In conclusion, the TOR signaling pathway of abalone can be regulated by arginine, and SLC38A9 plays an essential role in this regulation. [ABSTRACT FROM AUTHOR]

A 100-day feeding trial was conducted to investigate the effects of dietary lipid on growth performance and lipid deposition as well as the regulation mechanism in abalone Haliotis discus hannai Ino. Abalones (initial weight: 10.98 ± 0.05 g) were fed with graded levels of dietary lipid (1.57%, 2.34%, 3.17%, 3.82%, 4.63%, 5.56%, 6.17% and 6.72%). Results showed that weight gain rate (WGR) and increment in shell length of abalone were highest in 3.82% dietary lipid level. Based on the quadratic regression analysis for WGR, the optimal dietary lipid level for abalone was estimated to be 3.87%. Concentrations of the total triacylglycerol, low-density lipoprotein cholesterol and non-esterified fatty acids in serum as well as lipid contents in hepatopancreas and muscle were positively related to dietary lipid levels. Compared to the group with 3.82% of dietary lipid, higher (6.72%) and lower (1.57%) dietary lipid down regulated the expression of genes involved in fatty acids transport and lipolysis in hepatopancreas and muscle, which might be related to AMP-activated protein kinase α2 (AMPKα2)/peroxisome proliferator-activated receptor α (PPARα) signaling. Higher dietary lipid (6.72%) down regulated, while lower dietary lipid (1.57%) up-regulated the expressions of genes involved in de - novo lipogenesis in hepatopancreas. Both higher (6.72%) and lower (1.57%) dietary lipid down regulated these genes' expression in muscle. It was found that c-Jun N-terminal kinases (JNK)/mammalian target of rapamycin (mTOR)/sterol regulatory element-binding protein 1c (SREBP-1c) signaling participate in the regulation of de - novo lipogenesis. In conclusion, lipid deposition in abalone was affected by dietary lipid levels through AMPKα2/PPARα and JNK/mTOR/SREBP-1c pathway. • The optimal dietary lipid level for abalone was estimated to be 3.87%. • Dietary lipids increased the lipid deposition in abalone. • 6.72% or 1.57% dietary lipid regulated lipolysis through (ATGL, HSL)/AMPKα2/PPARα pathway. • 6.72% or 1.57% dietary lipid regulated lipogenesis through JNK/mTOR/SREBP-1c pathway. [ABSTRACT FROM AUTHOR]

The forkhead box O (FoxO) subfamily is a member of the forkhead transcription factor family. It has regulation functions in glucose metabolism in mammals and fish. In the present study, a gene of the foxo homolog in abalone Haliotis discus hannai was cloned. A conservative forkhead (FH) domain and a transactivation (FoxO-TAD) domain were identified. Abalone foxo-specific siRNA (small interfering RNA) was injected to investigate the functions of foxo on glucose metabolism. Knockdown of foxo inhibited expression of phosphoenolpyruvate carboxykinase (pepck) and significantly increased expressions of hexokinase (hk) and pyruvate kinase (pk), but it failed to inhibit the relative mRNA level of glucose-6-phosphatase (g6pase). Then, a 100-day feeding trial was conducted to investigate the response of foxo and glucose metabolism in abalone fed with 1.57% (LFD, low-fat diet), 3.82% (MFD, middle-fat diet) and 6.72% (HFD, high-fat diet) of dietary lipid, respectively. The insulin-signaling pathway (AKT) was depressed and FoxO was activated by the HFD, but it did not inhibit glycolysis (hk) or improved gluconeogenesis significantly (pepck and g6pase). At the same time, impaired hepatopancreas glycogen storage raised hemolymph glucose levels. In conclusion, abalone foxo can be regulated by dietary lipid and can regulate gluconeogenesis or glycolysis in response to changes of dietary lipid levels, in which glycogen metabolism plays an important role. [ABSTRACT FROM AUTHOR]

A 110-day feeding trial was carried out to investigate the impacts of replacing dietary fish meal (FM) with poultry by-product meal (PBM) on growth performance, digestion, gut microbiota, immunity, and disease resistance of abalone Haliotis discus hannai (initial weight: 22.53 ± 0.21 g). The control diet (PBM0) without PBM contained 20% of FM. Based on PBM0, the other four isonitrogenous (about 30% of crude protein) and isolipidic (about 4% of crude lipid) diets were formulated replacing 25, 50, 75 and 100% of FM by PBM (designated as PBM25, PBM50, PBM75 and PBM100), respectively. Every diet was fed to triplicate cages (40 × 35 × 70 cm) with 60 abalones per cage. At the end of the feeding trial, abalones were starved for 3 days and anesthetized with 5% ethanol before sampling. Results indicated that biomass gain of the abalone fed PBM75 (916.71 g) and PBM100 (659.93 g) was significantly lower than that of the abalone fed PBM0 (1222.51 g). Feed conversion ratio of the abalone fed PBM50 (2.93), PBM75 (2.89) and PBM100 (4.04) were significantly higher than that of the abalone fed PBM0 (2.37). The muscle crude protein content of the abalone fed PBM100 (16.01% wet weight) was significantly lower than that of the abalone fed PBM0 (16.67% wet weight). Activities of trypsin and α-amylase in the digestive gland in the PBM100 group (309.21 and 0.064 U/mg prot., respectively) were significantly lower than the PBM0 group (463.57 and 0.078 U/mg prot., respectively). When the substitution levels rose over 50%, expressions of phosphatidylinositol 3 kinase, threonine kinase/protein B, mammalian target of rapamycin and eukaryotic translation initiation factor 4E in muscle were significantly reduced, while 4E binding protein was significantly increased. The most abundant phyla across the abalones' gut were Proteobacteria and Firmicutes. Catalase (from 2.90 to 1.69 U/mL), superoxide dismutase (from 98.93 to 74.39 U/mL), lysozyme (from 345.86 to 247.81 U/mL) and acid phosphatase (from 21.68 to 15.71 U/100 mL) activities in cell-free hemolymph were markedly decreased with substitution level increasing. When the replacement levels rose over 50%, myeloid differentiation primary response gene 88 and tumor necrosis factor α expressions in the digestive gland were markedly upregulated, while β-defensin and mytimacin 6 expressions were markedly downregulated. The cumulative mortality of abalone challenged with Vibrio parahaemolyticus (1.0 × 107 CFU/mL) for 7 days was remarkably increased in the PBM50 (83.49%), PBM75 (89.56%) and PBM100 (100%) groups compared with the PBM0 group (58.82%). In conclusion, 50% of dietary FM could be replaced by PBM without influencing abalone growth. When the replacement level was over 50%, the growth and immunity of abalone were decreased, and the mTOR pathway was negatively affected. • Replacement of dietary fishmeal (FM, 0–20%) by poultry by-product meal (PBM, 0–20.5%) was evaluated in abalone. • The control diet was formulated with 20% of FM and without PBM. • There were no adverse effects on growth when replacement was 50% or less. • Negative effects on growth, immunity and disease resistance were found when PBM replaced more than 50% of FM. • The PBM can be used as an important protein source in the diet for abalone. [ABSTRACT FROM AUTHOR]

A 110-day feeding trial was conducted to investigate the effects of dietary chromium (Cr) on the growth performance, immune response, anti-oxidative capacity, stress resistance, flesh quality of abalone Haliotis discus hannai. Seven isonitrogenous and isolipidic experimental diets were formulated with graded levels of Cr (0.04, 0.67, 1.21, 1.58, 2.21, 2.72 and 3.33 mg/kg) from Cr yeast. The results showed that weight gain rate (WGR) was highest in the group with 1.21 mg/kg of dietary Cr. Based on the broken-line regression analysis for WGR, the dietary Cr requirement of abalone was estimated to be 1.32 mg/kg. With the increase of dietary Cr level from 0.04 to 1.21 mg/kg, the total anti-oxidative capacity and lysozyme activity in the cell-free hemolymph were increased and then decreased when the dietary Cr level exceeded 1.21 mg/kg. After the challenge of Vibrio parahaemolyticus , the cumulative mortality of abalone was significantly decreased in the group with 1.21 mg/kg of dietary Cr compared with that in the control group. Meanwhile, after the heat stress test, the cumulative mortality of abalone was significantly reduced in the groups with 1.58, 2.21 and 2.72 mg/kg of dietary Cr compared with that in the control group. The liquid and water loss of foot muscle were significantly increased in the groups with 2.72 and 3.33 mg/kg of dietary Cr. With the increase of dietary Cr levels, the hardness of foot muscle was significantly elevated. The chewiness of foot muscle was significantly increased with the increase of dietary Cr level from 0.04 to 1.21 mg/kg, and thereafter showed no significant difference when dietary Cr exceeded 1.21 mg/kg. In conclusion, based on the WGR, dietary Cr requirement of abalone (initial weight: 22.31 ± 0.31 g) was estimated to be 1.32 mg/kg. Appropriate dietary Cr levels (1.21–1.58 mg/kg) had positive effects on growth performance, immune response, anti-oxidation, anti-stress and flesh quality of abalone. Overhigh dietary Cr level (2.72–3.33 mg/kg) decreased the flesh quality. Excessive dietary Cr level (3.33 mg/kg) had a negative effect on the health of abalone. • The dietary chromium requirement of abalone was estimated to be 1.32 mg/kg. • Overhigh dietary Cr level (2.72–3.33 mg/kg) decreased the flesh quality. • Excessive dietary Cr level (3.33 mg/kg) had a negative effect on the health of abalone. • Chromium could accumulate in the muscle of abalone. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of different dietary carbohydrate levels on the growth performance, body composition, glucose/lipid metabolism and insulin signaling pathway in abalone Haliotis discus hannai. Eight experimental diets with graded levels of carbohydrates (18.08%, 22.10%, 26.10%, 29.90%, 34.00%, 38.01%, 41.98% and 45.55%, named as T1, T2, T3, T4, T5, T6, T7 and T8, respectively) were designed to feed abalone (initial weight 22.52 ± 0.05 g) for 110 days. The results showed that the diet containing 38.01% carbohydrate significantly increased the survival rate (SR) and weight gain rate (WGR) of abalone (P < 0.05). Based on the quadratic regression mode of WGR, the optimal dietary carbohydrate level for abalone was estimated to be 37.05%. The activities of intestinal digestive enzymes were significantly increased in the T6 group. Moreover, the expressions of pyruvate kinase (pk) and glucose-6-phosphate dehydrogenase (g6pdh) in digestive glands were up-regulated with the increase of carbohydrate content in diets, while the expression of hexokinase (hk) reached the maximum in the T6 group. The highest expressions of phosphoenolpyruvate carboxykinase (pepck), glucose-6-phosphatase (g6pase) and insulin signaling pathway related genes were found in the T6 group. The expressions of key genes related to lipolysis reached the highest in the T6 group, and then down-regulated with the further increasing dietary carbohydrate levels. The expression of key genes of lipogenesis was up-regulated with the increasing dietary carbohydrate levels. In conclusion, 38.01% of dietary carbohydrate level improved the growth performance of abalone. Dietary carbohydrate levels influenced the glucose and lipid metabolism including insulin signaling pathway. Abalone potentially had the capability to deal with a high-carbohydrate load (45.55%) by increasing glycolysis and decreasing gluconeogenesis. Meanwhile, it promoted lipid synthesis and inhibited lipolysis under high dietary carbohydrate load. • The dietary carbohydrate requirement of abalone was estimated to be 37.05%. • Deficient (18.10%) or excessive (45.55%) dietary carbohydrate content decreased the growth of abalone. • Appropriate dietary carbohydrate content increased the digestive enzyme activities in abalone. • Dietary carbohydrate levels increased the crude lipid content in the soft body of abalone. • Glucose and lipid metabolism including the insulin signaling pathway were regulated by dietary carbohydrate levels. [ABSTRACT FROM AUTHOR]

The present study was conducted to evaluate the replacement of dietary fish meal (FM) with Clostridium autoethanogenum protein (CAP) on abalone Haliotis discus hannai. Five isonitrogenous and isolipidic experimental diets with graded levels of FM replaced by CAP (0, 25, 50, 75 and 100%, respectively) were fed to abalone (initial weight: 21.83 ± 0.25 g) for 110 days. The five diets were named as CAP0, CAP25, CAP50, CAP75 and CAP100, respectively. The results showed that total replacement of dietary FM by CAP did not significantly affect the growth of abalone compared with the control. The highest weight gain rate was observed in the CAP25 group. Compared to the CAP0 group, the CAP25 group also had significantly higher total essential amino acids content in muscle and trypsin activity in digestive gland. The expressions of mammalian target of rapamycin, phosphatidylinositol 3-kinase and threonine kinase/protein B were significantly upregulated, and the expression of AMP-activated protein kinase α2 was significantly downregulated in the muscle of abalone in the CAP25 and CAP50 groups. The crude protein content, hardness, hydroxyproline content, pH value, pyridinium crosslink content, activities of lysyl hydroxylase and prolyl 4-hydroxylase in muscle were significantly elevated in the CAP25 and CAP50 groups. Considering the growth performance, digestion, mTOR pathways and muscle quality, 25% replacement of dietary FM by CAP (4.1% of dietary CAP inclusion level) was recommended for abalone. • Replacement of dietary fish meal (FM) with Clostridium autoethanogenum protein (CAP) on abalone was studied. • Total replacement of dietary FM by CAP did not significantly affect the growth of abalone. • The 25% replacement of dietary FM by CAP (equivalent to 4.1% of CAP in diet) significantly increased the growth of abalone. • Proper dietary CAP inclusion levels (4.1% and 8.15%) had positive effects on mTOR pathways and muscle quality of abalone. • The CAP can be used as an important protein source in the practical diet for abalone. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of replacing fish meal with soybean meal (SBM) on growth performance, immunity, anti-oxidative capacity and mTOR pathway in juvenile abalone Haliotis discus hannai Ino. Five isonitrogenous (about 29% of crude protein) and isolipidic (about 4% of crude lipid) experimental diets with graded levels of fish meal replaced by SBM (0, 25, 50, 75 and 100%, respectively) were fed to abalone (initial body weight: 21.87 ± 0.07 g, initial shell length: 53.18 ± 0.18 mm) for 16 weeks. These experimental diets were named as SBM0, SBM25, SBM50, SBM75 and SBM100, respectively. The results showed that: 1) There was no significant difference in survival of abalone among all the treatments. The highest weight gain rate was found in the SBM50 group, and the group did not significantly differ from those in the SBM75 and SBM100 groups. 2) Replacement of fish meal by SBM linearly and quadratically increased the crude lipid content in muscle of abalone, which reached its highest level in the SBM50 group. 3) Trypsin activity in the digestive gland of abalone fed SBM25 diet was significantly higher than that of other groups. 4) The highest total anti-oxidative capacity and superoxidase activity in digestive gland were found in the SBM50 group. 5) The highest mRNA levels of pi3k and eif-4e , and the lowest level of 4e-bp in muscle were found in the SBM50 group. There was no significant difference in the mRNA level of mtor in the muscle among all the groups. 6). The lowest expression level of nf-κb and the highest expression level of mytimacin 6 in digestive gland of abalone were observed fed SBM50 diet. A significant quadratic trend was found in the mRNA levels of il-16 with increasing levels of dietary SBM. Meanwhile, the mRNA level of β-defensin was linearly decreased after total replacement of fish meal by SBM. Take the growth, antioxidation, immune and mTOR pathway into account, 50% replacement of dietary fish meal by SBM was recommended for abalone. • A control diet was designed to have 20% of fish meal (FM) in the present study. • Compared to the control, 50% replacement of dietary FM by soybean meal (SBM) had significantly higher growth of abalone. • 50% replacement of dietary FM by SBM had positive effects on the mTOR pathway. • Higher replacement level (≥75%) decreased the anti-oxidative capacity of abalone. • Total replacement of dietary FM by SBM had negative effects on the histology of digestive gland. [ABSTRACT FROM AUTHOR]