The binding of soybean agglutinin (SBA) to the intestinal epithelium of Atlantic salmon, Salmo salar and rainbow trout, Oncorhynchus mykiss, fed high levels of soybean meal

Dietary cholesterol intervention could alleviate the intestinal injury of Oreochromis niloticus induced by plant-based diet via the intestinal barriers

This study aims to explore the effects of supplementing cholesterol in plant-based feed on intestinal barriers (including physical barrier, chemical barrier, immune barrier, biological barrier) of GIFT strain tilapia (Oreochromis niloticus). Four isonitrogenous and isolipidic diets were prepared as follows: plant-based protein diet (Con group) containing corn protein powder, soybean meal, cottonseed meal, and rapeseed meal, with the addition of cholesterol at a level of 0.6 % (C0.6 % group), 1.2 % (C1.2 % group), and 1.8 % (C1.8 % group), respectively. A total of 360 fish (mean initial weight of (6.08 ± 0.12) g) were divided into 12 tanks with 30 fish per tank, each treatment was set with three tanks and the feeding period lasted 9 weeks. Histological analysis revealed that both the C0.6 % and C1.2 % groups exhibited a more organized intestinal structure, with significantly increased muscle layer thickness compared to the Con group (P < 0.05). Furthermore, in the C1.2 % group, there was a significant up-regulation of tight junction-related genes (claudin-14, occludin, zo-1) compared to the Con group (P < 0.05). 5-ethynyl-2'-deoxyuridine staining results also demonstrated a notable enhancement in intestinal cell proliferation within the C1.2 % group (P < 0.05). Regarding the intestinal chemical barrier, trypsin and lipase activities were significantly elevated in the C1.2 % group (P < 0.05), while hepcidin gene expression was considerably down-regulated in this group but up-regulated in the C1.8 % group (P < 0.05). In terms of the intestinal immune barrier, inflammation-related gene expression levels (tnf-α, il-1β, caspase 9, ire1, perk, atf6) were markedly reduced in the C1.2 % group (P < 0.05). Regarding the intestinal biological barrier, the composition of the intestinal microbiota indicated that compared to the Con group, both the 0.6 % and 1.2 % groups showed a significant increase in Shannon index (P < 0.05). Additionally, there was a significant increase in the abundance of Firmicutes and Clostridium in the C1.2 % group (P < 0.05). In summary, supplementation of 1.2 % cholesterol in the plant-based diet exhibits the potential to enhance intestinal tight junction function and improve the composition of intestinal microbiota, thereby significantly promoting tilapia's intestinal health.

Effect of temperature on structural configuration and immunoreactivity of pH-stressed soybean (Glycine max) agglutinin

Soybean agglutinin (SBA) was purified using ammonium sulfate precipitation and liquid chromatography. Purified SBA was used to produce monoclonal antibodies through hybridoma technology. SBA secondary structure was studied using circular dichroism. pH-stressed (pHs 3.0, 7.2, 8.5, and 9.6) SBA physical properties (particle size, ζ-potential, and aggregation temperature) were investigated. Gel electrophoresis (non-native and native) was used to study heat-induced structural configuration changes in SBA. The effect of pH and temperature on the immunoreactivity of SBA was analyzed using enzyme-linked immunosorbent assay and immunoblots probed with two anti-SBA monoclonal antibodies with either linear or conformational epitopes. The hemagglutinating activity of heated SBA was measured by hemagglutination assay. Our results indicated that SBA had the least thermostability at pH 3.0 and the highest at pH 8.5. Temperature-induced structural configuration change on pH-stressed SBA led to immunoreactivity change. Heat-induced (70 and 80 °C) soluble SBA aggregation was proportionally related to hemagglutinating activity reduction.

Reparative effect of different dietary additives on soybean meal-induced intestinal injury in yellow drum (Nibea albiflora)

Soybean meal (SBM) is an acceptable replacement for unsustainable marine fish meal (FM) in aquaculture. However, we previously reported that high dietary SBM supplementation causes intestinal inflammatory injury in yellow drum (Nibea albiflora). Accordingly, a 4-week SBM-induced enteritis (SBMIE) in yellow drum trial was conducted first, followed by a 4-week additive-supplemented reparative experiment to evaluate the reparative effect of five additives on SBMIE in yellow drum. The control diet comprised 50% FM protein substituted with SBM. The additive-supplemented diet was added with 0.02% curcumin (SBMC), 0.05% berberine (SBM-BBR), 0.5% tea polyphenols (SBM-TPS), 1% taurine (SBM-TAU), or 0.8% glutamine (SBM-GLU) based on the control diet, respectively. The weight gain (WG), specific growth rate (SGR), feed efficiency ratio (FER), and survival rate (SR) of fish fed the additive-supplemented diets were significantly higher than those of fish fed the SBM diet. The WG, SGR, and FER of fish fed the SBMC, SBM-GLU and SBM-TAU diets were significantly higher than those of fish fed other diets. Moreover, fish fed the additive-supplemented diets SBMC and SBM-GLU, exhibited significantly increased intestinal villus height (IVH), intestinal muscular thickness (IMRT), and intestinal mucosal thickness (IMLT) and significantly decreased crypt depth (CD) in comparison with those fed the SBM diets. The relative expression of intestinal tight junction factors (ocln, zo1), cytoskeletal factors (f-actin, arp2/3), and anti-inflammatory cytokines (il10, tgfb) mRNA was remarkably elevated in fish fed additive-supplemented diets than those of fish fed the SBM diet. Whereas, the relative expression of intestinal myosin light chain kinase (mlck) and pro-inflammatory cytokines (il1, il6, tnfa) mRNA was markedly lower in fish fed the additive-supplemented diets. The highest relative expression of intestinal ocln, f-actin, and arp2/3 and the lowest relative expression of intestinal mlck were found in fish fed the SBMC diet. Hence, all five dietary additives effectively repaired the intestinal injury induced by SBM, with curcumin exhibiting the strongest repair effect for SBMIE in yellow drum.

Glutamine improves growth and intestinal health in juvenile hybrid groupers fed high-dose glycinin

Glutamine addition can improve immunity and intestinal development in fish. This study examined the protective roles of glutamine on growth suppression and enteritis induced by glycinin in juvenile hybrid groupers (female Epinephelus fuscoguttatus × male Epinephelus lanceolatus). The experiment set four isonitrogenous and isolipidic trial diets: a diet containing 10% glycinin (11S), 10% of 11S diet supplemented with 1% or 2% alanine-glutamine (1% or 2% Ala-Gln), and a diet containing neither 11S nor Ala-Gln (FM). A feeding trial was conducted in hybrid grouper for 8 weeks. Weight gain and specific growth rates in Groups 1% and 2% Ala-Gln were significantly higher than those of the 11S group but were similar to those of the FM group. The intestinal muscular layer thickness, plica height and width of the 2% Ala-Gln group were significantly higher than those of Group 11S. The enterocyte proliferation efficiency of the 11S group was significantly lower compared to other groups. Compared with the 11S group, Groups 1% and 2% Ala-Gln fish had increased intestinal lysozyme activities, complement 3 and immunoglobulin M as well as cathelicidin contents. The mRNA levels of tnf-α, il-1β, ifn-α, and hsp70 genes were more downregulated in Groups 1% and 2% Ala-Gln than in Group 11S. Compared with FM group, fish from the 11S group had significantly lower mRNA levels of myd88, ikkβ, and nf-κb p65 genes. These three values in the 2% Ala-Gln group were significantly lower than those in Group 11S but not significantly different from those of Group FM. The relative abundance of Vibrio in Group 11S was higher than that in Groups FM and 2% Ala-Gln. Intestinal glutamine, glutaminase, glutamic acid, α-ketoglutarate, malate dehydrogenase and ATP contents were higher in Groups 1% and 2% Ala-Gln than in Group 11S. These results suggest that glutamine is a useful feed additive to enhance growth and intestinal immunity, alleviate inflammation, and modulate gut microbiota in hybrid grouper fed high-dose glycinin.

Evaluation of Fermented Soybean Meal to Replace a Portion Fish Meal on Growth Performance, Antioxidant Capacity, Immunity, and mTOR Signaling Pathway of Coho Salmon (Oncorhynchus kisutch)

In this study, we evaluated the effects of fermented soybean meal (FSBM) or/and unfermented SBM replacing a portion of fish meal (FM) on the growth performance, antioxidant capacity, immunity, and mechanistic target of rapamycin (mTOR) signaling pathway of juvenile coho salmon (Oncorhynchus kisutch). Four groups of juvenile coho salmon (initial weight 152.23 ± 3.21 g) in triplicate were fed for 12 weeks on four different iso-nitrogen and iso-lipid experimental diets: G0 diet (28% FM protein, control group), G1 diet (18% FM protein and 10% SBM protein), G2 diet (18% FM protein, 5% SBM protein, and 5% FSBM protein), and G3 diet (18% FM protein and 10% FSBM protein). The main results were compared with the G0 diet; the weight gain rate, specific growth rate, and condition factor of juveniles in G3 were increased significantly (p < 0.05). The content of muscle crude protein, the total protein, glucose, albumin, total cholesterol in serum, and the total antioxidant capacity in the liver of juveniles in G3 was increased significantly (p < 0.05). The activities of pepsin, trypsin, α-amylase, and lipase in the intestine, the superoxide dismutase, catalase, and alkaline phosphatase in the liver of juveniles in G3 were increased significantly (p < 0.05). The expression levels of phosphatidylinositide 3-kinases, serine/threonine kinase, mTOR, and ribosomal protein S6 kinase 1 genes in the liver of juveniles in G3 were upregulated significantly (p < 0.05). The feed coefficient ratio, viscerosomatic index, the contents of muscle moisture, and malondialdehyde in the liver of juveniles in G3 were decreased significantly (p < 0.05). The expression levels of tumor necrosis factor α, interleukin 1β, and interleukin 6 genes in the liver of juveniles in G3 were downregulated significantly (p < 0.05). However, there was no significant effect (p > 0.05) on the survival rate, food intake, and muscle crude lipid and ash of juveniles among the experimental groups. In conclusion, FSBM to replace a portion FM had a positive effect on the growth performance, protein deposition, antioxidant enzyme activity, digestive enzyme activity, protein synthesis, and immune-related genes of juvenile coho salmon.

How Do Alternative Protein Resources Affect the Intestine Morphology and Microbiota of Atlantic Salmon?

The availability and cost of fishmeal constitute a bottleneck in Atlantic salmon production expansion. Fishmeal is produced from wild fish species and constitutes the major feed ingredient in carnivorous species such as the Atlantic salmon. These natural stocks are at risk of depletion and it is therefore of major importance to find alternative protein sources that meet the nutritional requirements of the Atlantic salmon, without compromising the animals' health. Terrestrial animal by-products have been used in aquaculture feed, but their use is limited by the lack of several essential amino acids and consumer acceptance. In the case of plant ingredients, it is necessary to take into account both their concentration and the extraction methodologies, since, if not dosed correctly, they can cause macro- and microscopic alterations of the structure of the gastrointestinal tract and can also negatively modulate the microbiota composition. These alterations may compromise the digestive functions, growth of the animal, and, ultimately, its well-being. An updated revision of alternative protein sources is provided, with the respective impact on the intestine health in terms of both morphology and microbiota composition. Such information may constitute the premise for the choice and development of Atlantic salmon feeds that guarantee fish health and growth performance without having a significant impact on the surrounding environment, both in terms of depletion of the fish's natural stocks and in terms of pressure on the terrestrial agriculture. The sustainability of aquaculture should be a priority when choosing next-generation ingredients.

Effects of partially replacing fishmeal with corn gluten meal on growth, feed utilization, digestive enzyme activity, and apparent nutrient digestibility for juvenile white shrimp, Litopenaeus vannamei

This experiment was conducted to assess the possibility of replacing fishmeal (FM, Fishmeal content of the control group: 30%) with corn gluten meal (CGM) at the following levels: 0, 10, 20, 30, 40, and 60%. The experimental diets, formulated to be isonitrogenous and isocaloric, were studied for their effects on growth, feed utilization, digestive enzyme activity and apparent nutrient digestibility in juvenile white shrimps, Litopenaeus vannamei (initial mean weight = 0.71 ± 0.01 g). Seven hundred twenty healthy and uniformed-size shrimp were distributed to six groups of three replicates, each with 40 shrimp in each tank (0.5 m³). Each experimental diet was fed to shrimp four times daily to apparent satiation at 7:00, 11:30, 17:00, and 21:30, respectively, for 8 weeks. At the end of the experiment, the total weight of fish in each tank was weighed and randomly selected for testing, including fish nutrient composition and digestive enzyme activity. Results showed that no significant differences were observed in the weight gain rate (WGR), feed coefficient rate (FCR) and specific growth rate (SGR) of shrimp after 30% FM was replaced with CGM (P > 0.05), but these indicators significantly decreased at higher replacement rates. As CGM content increased, the content of crude protein and phosphorus in the shrimp decreased significantly (P < 0.05), whereas the crude fat content first increased significantly and then decreased (P < 0.05). Compared to the control group, the protease activity was significantly lower in the 40% group and the lipase activity was significantly lower in the 60% group (P < 0.05). Amylase activity was significantly increased with increasing CGM levels (P < 0.05). The digestibility of protein and lipid was significantly reduced by CGM replacement of more than 30% FM (P < 0.05). As CGM content increased, the digestion of energy and dry matter was first significantly increased and then significantly decreased (P < 0.05). In the 30, 40, and 60% groups, the digestibility of all amino acids (AA), except methionine (Met), arginine (Arg) and serine (Ser), was significantly lower than in the control group (P < 0.05). In summary, FM could be partially replaced by CGM in the feed of L. vannamei. Based on the broken-line regression analysis of WGR, the optimal dietary CGM replacement was 27.47%.

Commensal Bacillus siamensis LF4 ameliorates β-conglycinin induced inflammation in intestinal epithelial cells of Lateolabrax maculatus

β-conglycinin and glycinin, two major heat-stable anti-nutritional factors in soybean meal (SM), have been suggested as the key inducers of intestinal inflammation in aquatic animals. In the present study, a spotted seabass intestinal epithelial cells (IECs) were used to compare the inflammation-inducing effects of β-conglycinin and glycinin. The results showed that IECs co-cultured with 1.0 mg/mL β-conglycinin for 12 h or 1.5 mg/mL glycinin for 24 h significantly decreased the cell viability (P < 0.05), and overstimulated inflammation and apoptosis response by significantly down-regulating anti-inflammatory genes (IL-2, IL-4, IL-10 and TGF-β1) expressions and significantly up-regulated pro-inflammatory genes (IL-1β, IL-8 and TNF-α) and apoptosis genes (caspase 3, caspase 8 and caspase 9) expressions (P < 0.05). Subsequently, a β-conglycinin based inflammation IECs model was established and used for demonstrating whether commensal probiotic B. siamensis LF4 can ameliorate the adverse effects of β-conglycinin. The results showed β-conglycinin-induced cell viability damage was completely repaired by treated with 10⁹ cells/mL heat-killed B. siamensis LF4 for ≥12 h. At the same time, IECs co-cultured with 10⁹ cells/mL heat-killed B. siamensis LF4 for 24 h significantly ameliorated β-conglycinin-induced inflammation and apoptosis by up-regulating anti-inflammatory genes (IL-2, IL-4, IL-10 and TGF-β1) expressions and down-regulated pro-inflammatory genes (IL-1β, IL-8 and TNF-α) and apoptosis genes (caspase 3, caspase 8 and caspase 9) expressions (P < 0.05). In summary, both β-conglycinin and glycinin can lead to inflammation and apoptosis in spotted seabass IECs, and β-conglycinin is more effective; commensal B. siamensis LF4 can efficiently ameliorate β-conglycinin induced inflammation and apoptosis in IECs.

The apoptotic effects of soybean agglutinin were induced through three different signal pathways by down-regulating cytoskeleton proteins in IPEC-J2 cells

Soybean agglutinin (SBA) is a main anti-nutritional factor in soybean. SBA exhibits its anti-nutritional functions by binding to intestinal epithelial cells. Keratin8 (KRT8), Keratin18 (KRT18) and Actin (ACTA) are the representative SBA-specific binding proteins. Such cytoskeletal proteins act a crucial role in different cell activities. However, limited reports reveal what the signal transduction pathway of apoptosis caused by SBA when binding to KRT8, KRT18 and ACTA. We aimed to evaluate the effects of SBA on cell apoptosis and the expression of the cytoskeletal protein (KRT8, KRT18 and ACTA), reveal the roles of these cytoskeletal proteins or their combinations on SBA-induced cell apoptosis in IPEC-J2 cell line, evaluate the influences of SBA on the mitochondria, endoplasmic reticulum stress and death receptor-mediated apoptosis signal pathway and to show the roles of KRT8, KRT18 and ACTA in different apoptosis signal pathways induced by SBA. The results showed that SBA induced the IPEC-J2 cell apoptosis and decreased the mRNA expression of KRT8, KRT18 and ACTA (p < 0.05). The degree of effect of three cytoskeleton proteins on cell apoptosis was ACTA > KRT8 > KRT18. The roles of these three cytoskeletal proteins on IPEC-J2 apoptotic rates had a certain accumulation effect. SBA up-regulated mitochondrial fission variant protein (FIS1) and fusion protein (Mfn2) promoted CytC and AIF in mitochondria to enter the cytoplasm, activated caspase-9 and caspase-3, damaged or declined mitochondrial function and reduced ATP synthesis (p < 0.05). Also, SBA up-regulated the expression of GRP78, XBP-1, eIF2α, p-eIF2α and CHOP (p < 0.05), down-regulated the expression level of ASK1 protein (p < 0.05). SBA led to the recruitment of FADD to the cytoplasmic membrane and increased the expression of FasL, resulting in caspase-8 processing. SBA up-regulated the expression level of Bax protein and decreased cytosolic Bcl-2 and Bid (p < 0.05). In addition, there was a significant negative correlation between the gene expression of cytoskeleton proteins and apoptosis, as well as the expression of key proteins of apoptosis-related signal transduction pathways. In conclusion, SBA induced the activation of the mitochondria, endoplasmic reticulum stress and the death receptor-mediated apoptosis signal pathway and the crosstalk between them. The effect of SBA on these three pathways was mainly exhibited via down-regulation of the mRNA expression of the three cytoskeletal expressions. This study elucidates the molecular mechanism and signaling pathway of SBA that lead to apoptosis from the perspective of cell biology and molecular biology and provides a new perspective on the toxicity mechanism of other food-derived anti-nutrients, medical gastrointestinal health and related cancer treatment.

Improvement of Soybean; A Way Forward Transition from Genetic Engineering to New Plant Breeding Technologies

Soybean is considered one of the important crops among legumes. Due to high nutritional contents in seed (proteins, sugars, oil, fatty acids, and amino acids), soybean is used globally for food, feed, and fuel. The primary consumption of soybean is vegetable oil and feed for chickens and livestock. Apart from this, soybean benefits soil fertility by fixing atmospheric nitrogen through root nodular bacteria. While conventional breeding is practiced for soybean improvement, with the advent of new biotechnological methods scientists have also engineered soybean to improve different traits (herbicide, insect, and disease resistance) to fulfill consumer requirements and to meet the global food deficiency. Genetic engineering (GE) techniques such as transgenesis and gene silencing help to minimize the risks and increase the adaptability of soybean. Recently, new plant breeding technologies (NPBTs) emerged such as zinc-finger nucleases, transcription activator-like effector nucleases, and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR/Cas9), which paved the way for enhanced genetic modification of soybean. These NPBTs have the potential to improve soybean via gene functional characterization precision genome engineering for trait improvement. Importantly, these NPBTs address the ethical and public acceptance issues related to genetic modifications and transgenesis in soybean. In the present review, we summarized the improvement of soybean through GE and NPBTs. The valuable traits that have been improved through GE for different constraints have been discussed. Moreover, the traits that have been improved through NPBTs and potential targets for soybean improvements via NPBTs and solutions for ethical and public acceptance are also presented.

Dietary Sodium Butyrate Improves Intestinal Health of Triploid Oncorhynchus mykiss Fed a Low Fish Meal Diet

This study aimed to determine the effects of dietary sodium butyrate (NaB) on the growth and gut health of triploid Oncorhynchus mykiss juveniles (8.86 ± 0.36 g) fed a low fish meal diet for 8 weeks, including the inflammatory response, histomorphology, and the composition and functional prediction of microbiota. Five isonitrogenous and isoenergetic practical diets (15.00% fish meal and 21.60% soybean meal) were supplemented with 0.00% (G1), 0.10% (G2), 0.20% (G3), 0.30% (G4), and 0.40% NaB (G5), respectively. After the feeding trial, the mortality for G3 challenged with Aeromonas salmonicida for 7 days was lower than that for G1 and G5. The optimal NaB requirement for triploid O. mykiss based on weight gain rate (WGR) and the specific growth rate (SGR) was estimated to be 0.22% and 0.20%, respectively. The activities of intestinal digestive enzymes increased in fish fed a NaB diet compared to G1 (p < 0.05). G1 also showed obvious signs of inflammation, but this inflammation was significantly alleviated with dietary NaB supplementation. In comparison, G3 exhibited a more complete intestinal mucosal morphology. Dietary 0.20% NaB may play an anti-inflammatory role by inhibiting the NF-κB-P65 inflammatory signaling pathway. Additionally, the relative abundance of probiotics was altered by dietary NaB. In conclusion, dietary 0.20% NaB improved the intestinal health of triploid O. mykiss fed a low fish meal diet.

Hepatopancreas-Intestinal Health in Grass Carp (Ctenopharyngodon idella) Fed with Hydrolyzable Tannin or Rapeseed Meal

This study evaluated the effect of dietary rapeseed meal (RM) and hydrolyzable tannin on grass carp (Ctenopharyngodon idella) and determined the possible role of tannin on health when RM was added to the diet. Eight diets were formulated. Four were semipurified-diets with 0, 0.75, 1.25, and 1.75% hydrolyzable tannin (T0, T1, T2, and T3), and the other four were practical diets containing 0, 30, 50, and 70% RM (R0, R30, R50, and R70), which had similar tannin contents as semipurified-diets. After the 56 d feeding trial, the antioxidative enzymes and relative biochemical indexes showed a similar tendency in practical and semipurified groups. In hepatopancreas, superoxide dismutase (SOD) and catalase (CAT) activities increased with RM and tannin levels, respectively, while glutathione (GSH) content and glutathione peroxidase (GPx) activity increased. Malondialdehyde (MDA) content increased and decreased in T3 and R70, respectively. In the intestine, MDA content and SOD activity increased with RM and tannin levels, while GSH content and GPx activity decreased. The expression levels of interleukin 8 (IL-8) and interleukin 10 (IL-10) were upregulated with RM and tannin levels, and the Kelch-like ECH-associated protein 1 (Keap1) expression was upregulated in T3, whereas it was downregulated in R50. This study demonstrated that 50% of RM and 0.75% of tannin induced oxidative stress, injured hepatic antioxidant ability, and resulted in intestinal inflammation in grass carp. Therefore, the tannin in rapeseed meal cannot be neglected in aquatic feeding.

Dietary yeast culture alleviates intestinal-hepatic damage related to TLR2-MyD88-NF-κB signaling pathway and antioxidant capability in Pseudobagrus ussuriensis

Yeast culture (YC), as a member of probiotics family is a natural product produced from yeast fermentation, affects of improving immunity. However, the intestine and liver injury and immunosuppression mechanism caused by SBA in fish are unclear and more functions of YC supplement in the diet need to be developed. Soybean agglutinin (SBA) is an anti-nutritional factor in soybean and leads to growth-inhibitory effect in feeding of the high proportion of soybean meal replacing fish meal (FM). Therefore, one hundred and thirty-five Pseudobagrus ussuriensis (6.5 ± 0.27 g) were randomly selected and divided into three groups (Control, SBA and YC+SBA groups). For the model, fish were fed with 2% YC for 8 weeks and then given intragastric administration of 0.2-mL SBA solution for 20 days. The results showed that SBA damaged the immune and antioxidant capacity, causing an inflammatory reaction, leading to abnormal expression of cytokines in the intestine and liver of Pseudobagrus ussuriensis. YC could effectively attenuate intestinal and liver damage and downregulate the TLR2/MyD88/NF-κB signaling pathway and suppress oxidative stress in Pseudobagrus ussuriensis. Besides, YC had obvious immune advantage, which could improve the immune ability. In summary, these results showed that YC could reduce immunosuppression and intestinal-liver injury by inhibiting the TLR2/MyD88/NF-κB signal pathway and oxidative stress induced by SBA. This study provided some explanations for the problems of fish diet caused by anti-nutritional factors from soybean meal and provided a theoretical basis for the function development of YC in aquaculture.

Soybean β-conglycinin and glycinin reduced growth performance and the intestinal immune defense and altered microbiome in juvenile pearl gentian groupers Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂

The utilization efficiency of soy protein is affected by its 2 anti-nutritional substances-the antigens β-conglycinin and glycinin. This study investigated their effects on the growth performance, intestinal immune defense, and microbiome in juvenile pearl gentian groupers (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂). Three isonitrogenous and isolipidic diets were formulated containing fishmeal supplemented with 70 g/kg β-conglycinin or 100 g/kg glycinin, or no supplementation (control). Each experimental diet was fed to quadruplicate groups with 30 fish in each tank for 8 weeks. Dietary inclusion of either β-conglycinin or glycinin significantly reduced weight gain and specific growth rates, and cell proliferation of the distal intestine. Histological evaluation of the intestine tract revealed the inflammation signs, characterized by reducing of plica height and width as well as the number of the goblet cells, and widening of the lamina propria. The group fed the β-conglycinin diet had reduced lysozyme activity, contents of immunoglobulin M and complements 3 and 4. Increased activities of caspase-3 and -9 were observed in the group fed the β-conglycinin diet compared to the other 2 groups. In the intestinal microbiota, the relative abundances of the potentially pathogenic genera Photobacterium and Vibrio were significantly higher in the glycinin group than those in others. Therefore, the existence of soybean antigens (β-conglycinin or glycinin) could damage the structural integrity of the intestine, reduce immune defense, reshape the intestinal microbiome and, ultimately, impair growth in fish.

Effects of acid-hydrolyzed soybean meal on growth performance, jejunal morphology, digestive enzyme activities, nutrient utilization, and intestinal microbial population in broiler chickens

The objective of this study was to investigate the effects of soybean meal (SBM) treated with acetic or citric acids on growth performance, microbial population, digestive enzyme activities, nutrient digestibility, and jejunal morphology in broiler chickens. A total of 350 one-day-old male broiler chicks (Ross 308) were randomly distributed into 7 experimental groups with 5 replicates per each. Experimental treatments were diets containing untreated SBM (control) and SBM treated with two acid sources and their concentrations including 5, 10, and 15% acetic acid (A1, A2, and A3) or 0.25, 0.50, and 0.75% citric acid (C1, C2, and C3). Results showed that trypsin inhibitors and lectins as the main SBM anti-nutrients significantly reduced in acid-treated SBM compared with untreated SBM (P < 0.05). During 1-24 days, body weight gain increased in chicks fed the C2 diet (P < 0.05). Feeding of the C2 diet increased feed intake compared with A1, A2, and C3 groups (P < 0.05). Feed conversion ratio improved in chicks fed with C2, C3, and A2 diets compared with the control group (P < 0.05). The greatest villus length, villus length to crypt depth ratio, and villus surface area were observed in the C2 diet (P < 0.05). A significant increase in protease and lipase activity was found in broilers which received a C2 diet compared with the control group (P < 0.05). Broiler chickens fed with the C2 diet had a higher organic matter and crude protein digestibility than the chicks which received the control diet (P < 0.05) and dry matter digestibility was the lowest in broilers fed with the A3 diet (P < 0.05). In conclusion, the acid hydrolyzing process had a beneficial effect on the nutritional value of SBM. In addition, data showed that acid-hydrolyzed SBM had the potential to exert positive influences on growth performance, jejunal morphology, and nutrient utilization in broiler chickens.

A Multidisciplinary Approach Evaluating Soybean Meal-Induced Enteritis in Rainbow Trout Oncorhynchus mykiss

This study evaluated a diverse range of markers of feeding stress to obtain a more precise assessment of the welfare of rainbow trout in relation to inadequate husbandry conditions. A feeding stress model based on dietary soybean meal was employed to identify suitable minimally invasive “classical” stress markers, together with molecular signatures. In a 56-day feeding experiment, rainbow trout were fed diets containing different levels of soybean meal. The impact of these different soybean meal diets on rainbow trout was assessed by water quality analyses, clinical health observations, classic growth and performance parameters, gut histopathology, blood-parameter measurements and multigene-expression profiling in RNA from whole blood. Soybean meal-induced enteritis was manifested phenotypically by an inflammatory reaction in the posterior section of the intestine and by diarrhoea in some trout. These inflammatory changes were associated with decreased supranuclear vacuolation. The haematocrit values and the levels of plasma cortisol and circulating lymphocytes in the blood were increased in trout that had consumed high amounts of SBM. Notably, the increased haematocrit depended significantly on the bodyweight of the individual trout. The transcript levels of certain genes (e.g., MAP3K1, LYG, NOD1, STAT1 and HSP90AB) emerged as potentially useful indicators in the blood of rainbow trout providing valuable information about inadequate nutrition. The expression-profiling findings provide a basis for improved, minimally invasive monitoring of feeding regimens in trout farming and may stimulate the development of practical detection devices for innovative aquaculture operations.

Mitigative effects of Eleutheroside E against the mechanical barrier dysfunction induced by soybean agglutinin in IPEC-J2 cell line

Soybean agglutinin (SBA) is an anti-nutritional factor which decreases the mechanical barrier function in intestinal porcine jejunum epithelial cells (IPEC-J2). Eleutheroside E (EE) is a key part of Acanthopanax senticosus to exert pharmacological effects. This study aims to investigate the effects of EE on the barrier function in IPEC-J2 cells and to determine the ability of EE to enhance the protective effect of barrier function against SBA exposure. The IPEC-J2 cells were cultured in mediums with concentration of 0.1 mg/ml EE, 0.5 ml/ml SBA and 0.1 mg/ml EE pre-treated then treated with 0.5 mg/ml SBA. Then, the transepithelial electric resistance (TEER) value, inflammatory cytokines mRNA expression, tight junction mRNA and protein expression were tested by epithelial Voltohm meter, q-PCR and Western blot method respectively. The results showed that cells treated with 0.1 mg/ml EE had lower permeability (p < 0.05) while 0.5 mg/ml SBA treatment had higher permeability through tested TEER, and higher tight junction proteins (Claudin-3 and ZO-1) expressions and genes (Claudin-3, Occludin and ZO-1) expressions (p < 0.05) in 0.1 mg/ml EE group. IPEC-J2 cells pre-treated with 0.1 mg/ml EE could significantly improve the inflammatory response caused by 0.5 mg/ml SBA by up-regulation for IL-10, TGF-β, and down-regulation gene expression of IL-6, TNF-α and IFN-γ (p < 0.05). In conclusion, 0.1 mg/ml EE can improve the mechanical barrier function and could protect the effects while 0.5 mg/ml of SBA-induced barrier dysfunction in IPEC-J2.

Successful Inclusion of High Vegetable Protein Sources in Feed for Rainbow Trout without Decrement in Intestinal Health

The aquaculture of carnivorous fish is in continuous expansion, which leads to the need to reduce the dependence on fishmeal (FM). Plant proteins (PP) represent a suitable protein alternative to FM and are increasingly used in fish feed. However, PP may lead to stunted growth and enteritis. In the current study, the effect of high FM substitution by PP sources on the growth, mortality and intestinal health of rainbow trout (Oncorhynchus mykiss) was evaluated in terms of the histological intestine parameters and expression of genes related to inflammation (IL-1β, IL-8 and TGF-β) and immune responses (Transferrin, IgT and IFN-γ). The results show that a total substitution registered lower growth and survival rates, probably due to a disruption to the animal's health. Confirming this hypothesis, fish fed FM0 showed histological changes in the intestine and gene changes related to inflammatory responses, which in the long-term could have triggered an immunosuppression. The FM10 diet presented not only a similar expression to FM20 (control diet), but also similar growth and survival. Therefore, 90% of FM substitution was demonstrated as being feasible in this species using a PP blend of wheat gluten (WG) and soybean meal (SBM) as a protein source.

Optimization of Soybean Meal Fermentation for Aqua-Feed with Bacillus subtilis natto Using the Response Surface Methodology

This study aimed to improve the nutritional value of soybean meal (SBM) by solid-state fermentation (SSF) using Bacillus subtilis natto (B. s. natto) to overcome the limitations of SBM usage in aquafeed. The response surface methodology (RSM) was employed to explore the relationships of fermentation conditions, such as temperature, time, water-substrate ratio, and layer thickness, on the degree of protein hydrolysis (DH) and the crude protein (CP) content. The optimum conditions for achieving the higher DH (15.96%) and CP (55.76%) were 43.82 °C, 62.32 h, 1.08 of water-substrate ratio, and a layer thickness of 2.02 cm. CP and DH in the fermented soybean meal (FSM) increased by 9.8% and 177.1%, respectively, and crude fiber decreased by 14.1% compared to SBM. The protein dispersibility index (PDI) decreased by 29.8%, while KOH protein solubility (KPS) was significantly increased by 17.4%. Flavonoids and total phenolic acid content in FSM were increased by 231.0% and 309.4%, respectively. Neutral protease activity (NPA) also reached a high level (1723.6 U g−1). Total essential amino acids (EAA) in FSM increased by 12.2%, higher than the 10.8% increase of total non-essential amino acids (NEAA), while the total free amino acids content was 12.76 times higher than that of SBM. Major anti-nutritional factors in SBM were significantly reduced during the process, and almost all SBM protein macromolecules were decomposed. Together with the cost-effectiveness of SSF, B. s. natto-fermented SBM products have great potential to improve the plant composition and replace high-cost ingredients in aquafeed, contributing to food security and environmental sustainability.

Intestinal Transcriptome Analysis Reveals Soy Derivative-Linked Changes in Atlantic Salmon

Intestinal inflammation in farmed fish is a non-infectious disease that deserves attention because it is a major issue linked to carnivorous fishes. The current norm is to formulate feeds based on plant-derived substances, and the ingredients that have antinutritional factors are known to cause intestinal inflammation in fishes such as Atlantic salmon. Hence, we studied inflammatory responses in the distal intestine of Atlantic salmon that received a feed rich in soybean derivatives, employing histology, transcriptomic and flow cytometry techniques. The fish fed on soy products had altered intestinal morphology as well as upregulated inflammation-associated genes and aberrated ion transport-linked genes. The enriched pathways for the upregulated genes were among others taurine and hypotaurine metabolism, drug metabolism-cytochrome P450 and steroid biosynthesis. The enriched gene ontology terms belonged to transmembrane transporter- and channel-activities. Furthermore, soybean products altered the immune cell counts; lymphocyte-like cell populations were significantly higher in the whole blood of fish fed soy products than those of control fish. Interestingly, the transcriptome of the head kidney did not reveal any differential gene expression, unlike the observations in the distal intestine. The present study demonstrated that soybean derivatives could evoke marked changes in intestinal transport mechanisms and metabolic pathways, and these responses are likely to have a significant impact on the intestine of Atlantic salmon. Hence, soybean-induced enteritis in Atlantic salmon is an ideal model to investigate the inflammatory responses at the cellular and molecular levels.

Efficacy of mozuku fucoidan in alternative protein-based diet to improve growth, health performance, and stress resistance of juvenile red sea bream, Pagrus major

We evaluated the efficacy of mozuku fucoidan supplementation to alternative dietary proteins used in fish meal (FM) replacement to enhance growth, immunity, and stress resistance of Pagrus major. Seven isonitrogenous (45% protein) experimental diets were formulated where diet 1 (D1) was FM-based control diet. Diets 2 to 7 were formulated by replacing 25, 50, and 75% of FM protein with soy protein isolate (SPI) protein, and each replacement level was supplemented without or with fucoidan at 0.4% for diet groups D2 (FM25), D3 (FM25Fu), D4 (FM50), D5 (FM50Fu), D6 (FM75), and D7(FM75Fu), respectively. Each diet was randomly allocated to triplicate groups of fish (4.1 g) for 56 days. Significantly higher weight gain and specific growth rate were observed in fish fed FM50Fu diet group, and it was not differed (P > 0.05) with fish fed FM25Fu diet group. FM-based control diet showed intermediate value, and it was not differed (P > 0.05) with or without fucoidan-supplemented ≤ 50% FM replacement groups and FM75Fu diet group. Significantly lower growth performances were observed in FM75 diet group. At each replacement level, fucoidan-supplemented groups showed nonsignificant improvement of feed utilization performances. Fish fed fucoidan-supplemented diets showed best condition of oxidative and freshwater stress resistance. Lysozyme activity, NBT, and peroxidase activity showed higher (P > 0.05) values in fucoidan-supplemented groups compared with the non-supplemented groups. Catalase activity was significantly lower in FM75Fu diet group. Catalase activity is significantly influenced by the interaction effects of fucoidan and FM replacement level. In conclusion, fucoidan supplementation could increase the efficiency of utilizing SPI (≥ 75%) without any adverse effects on red sea bream performance.

Preliminary study of mechanisms of intestinal inflammation induced by plant proteins in juvenile hybrid groupers (♀Epinephelus fuscoguttatus×♂E. lanceolatu)

Fish fed a high plant protein diet exhibit intestinal inflammation, the mechanism of which needs to be clarified. We preliminarily elucidate the mechanism of the TLRs/MyD88-PI₃K/Akt signalling pathway in intestinal inflammation induced by plant proteins. The diets contained 60% fish meal (FM, controls), or had 45% of the fish meal protein replaced by soybean meal (SBM), peanut meal (PM), cottonseed meal (CSM) or cottonseed protein concentrate (CPC). After an 8-week feeding trial, fish were challenged by injection of Vibrio parahaemolyticus bacteria for 7 days until the fish stabilized. The results showed that the specific growth rate (SGR) of the FM group was higher than other groups. The SGR of the CPC group was higher than those of the SBM, PM and CSM groups. The catalase (CAT) contents in the serum of fish fed a plant protein diet were higher than in FM fish. The abundances of Rhodobacteraceae and Microbacteriaceae in the MI (mid intestine) were higher in the CPC group. The TLR-2 expressions in the MI and DI of plant protein-fed fish were up-regulated. The expressions of IL-6 in the PI and MI, of hepcidin and TLR-3 in the MI, and of TLR-3 in the DI, were all lower than those of fish fed FM. In the PI, MI and DI, the protein expressions of P-PI₃K/T-PI₃K in the SBM and PM groups were higher than in the FM group. After the challenge, the cumulative mortalities in the FM and CPC groups were lower than those of the SBM, PM and CSM groups. These results suggested that plant protein diets reduced antioxidant capacity and glycolipid metabolism, hindered the development of the intestine and reduced intestinal flora diversity. TLR-3 is involved in the immune regulation of the PI in CPC group, MI and DI in SBM, PM, CSM and CPC groups, while might be involved in the immune regulation of the PI in SBM, PM and CSM groups. Furthermore, PI₃K/Akt signaling does not participate in the regulation of PI and MI in the CSM group, MI and DI in the CPC group.

Effects of dietary raw or Enterococcus faecium fermented soybean meal on growth, antioxidant status, intestinal microbiota, morphology, and inflammatory responses in turbot (Scophthalmus maximus L.)

Fermentation has been reported to improve the utilization of plant ingredients including soybean meal (SBM) by fish, but the detailed mechanism is still poorly understood. This study compared the effects of partial replacement of fish meal (FM) protein with SBM or Enterococcus faecium fermented SBM (EFSM) on the growth, antioxidant status, intestinal microbiota, morphology, and inflammatory responses in turbot (Scophthalmus maximus L.). The FM-based diet was used as the control (CONT). Two experimental diets were formulated in which 45% of the FM protein was replaced with SBM or EFSM. Each diet was fed to triplicate groups of fish (7.57 ± 0.01 g) twice daily for 79 d. Inferior growth performance was observed in SBM group, however, no significant depression was observed in EFSM group compared to the CONT group. The CONT group had the highest values of lysozyme, complement component 3, total antioxidant capacity, superoxide dismutase and catalase, followed by the EFSM group, and the lowest in SBM group. The malondialdehyde content was lowest in the CONT group, followed by the EFSM group, and was highest in the SBM group. Gut morphology showed that SBM diet induced alterations typical for intestinal inflammation including decreased villus and microvillus height, and increased width and inflammatory cell infiltration of the lamina propria. However, the EFSM group alleviated such SBM-induced intestinal pathological disruption. Paralleled with the morphological symptoms, the inflammatory gene expression levels of tumor necrosis factor alpha, interleukin-1 beta and interleukin-8 were highest in the SBM group, followed by the EFSM group, and were lowest in the CONT group. Furthermore, the intestinal microbiota analysis revealed that EFSM group had an overall more similar microbiota with CONT group than SBM group. Specifically, compared with the SBM group, EFSM group significantly enhanced the probiotics Lactobacillus and anti-inflammatory bacterium Faecalibaculum, and inhibited the Vibrio. Collectively, this study indicated that Enterococcus faecium fermentation effectively counteracted the negative effects of SBM by enhancing antioxidant capacity, suppressing inflammatory responses, and modulating gut microbiota in turbot.

Growth and health of juvenile barramundi (Lates calcarifer) challenged with DO hypoxia after feeding various inclusions of germinated, fermented and untreated peanut meals

Peanut (Arachis hypogaea) is mainly grown for oil extraction and the remaining oil-free seed referred as peanut meal (PM) leaves with high protein content which can be a possible substitute for fishmeal in aqua-diets. This study evaluates the suitability of three types of processed peanut seeds, namely untreated PM (UPM), fermented PM (FPM), and germinated PM (GPM) from peanut seeds to replace fishmeal in barramundi (Lates calcarifer) diets cultured under a commercial production environment. Nine formulated diets having 3 inclusion levels from the 3 different peanuts (15%, 30% and 60% fishmeal replacement) were evaluated against a control without PM. The performance of various types and levels of PMs was assessed by examining the growth, gut and liver condition and survival of fish after eight weeks of feeding the test diets. The immunological responses of juvenile barramundi were assessed by exposing the fish to the hypoxic conditions for 4 hours. The results showed that fermentation and germination significantly (P<0.05) reduced the tannins and alkaloid contents in the PMs. The fish fed 15% GPM diet grew faster and had higher survival than fish fed control diet, while fish fed diet including 60% GPM showed a significant reduction in growth and survival, and an increase in food conversion rate (FCR). FPM and UPM at any inclusion levels did not alter the growth, survival and FCR. Histology analysis revealed that fish fed 60% GPM and UPM showed higher amount of lipid droplets in liver, myodigeneration in fish muscle and a decrease number of acidic mucins in distal gut compare to all other test diets. Stress caused by reduced dissolved oxygen did not change the sodium, potassium, chlorides and alanine aminotransferase concentrations of plasma of fish fed any diet. However, the stress did increase plasma cortisol significantly (P<0.05) in fish fed 60% GPM, 30% and 60% UPM diets. These results suggest that the PMs can partly replace the fishmeal in juvenile barramundi diet and the processing further improves the PMs quality by reducing its antinutritional factors which in turn can increase either its inclusion level in the barramundi diets or improved growth and health status of the species.

Beneficial influences of dietary Aspergillus awamori fermented soybean meal on oxidative homoeostasis and inflammatory response in turbot (Scophthalmus maximus L.)

High levels of soybean meal (SBM) in aquafeed leads to detrimental inflammatory response and oxidative stress in fish. In the present study, fermentation with Aspergillus awamori was conducted to explore the potential effects on improving the nutritional quality of soybean meal and the health status of turbot. A 63-day feeding trial (initial weight 8.53 ± 0.11 g) was carried out to evaluate the utilization of fermented soybean meal (FSM) by juvenile turbot. 0% (FM, control), 30% (S30, F30), 45% (S45, F45), and 60% (S60, F60) of fish meal were replaced with SBM or FSM, respectively. As the results showed, fermentation significantly reduced the contents of anti-nutritional factors in SBM, including raffinose (-98.8%), glycinin (-98.5%), β-conglycinin (-97.4%), trypsin inhibitors (-80%) and stachyose (-80%). A depression of fish growth performance and activities of superoxide dismutase and lysozyme were observed in S45 and S60 groups, while these inferiorities were only observed in F60 group. Meanwhile, fermentation also improved the heights of enterocytes and microvillus significantly in the F45 and F60 groups compared with those in SBM. An induced expression of anti-inflammatory cytokine transforming growth factor-β and depression of pro-inflammatory cytokines tumor necrosis factor-α and interleukin-1β in the distal intestine were observed in the F45 and F60 groups. Taken together, this study indicated that fermentation with Aspergillus awamori could improve the replacement level with soybean meal from 30% to 45% in turbot.

Differential Apoptotic and Mitogenic Effects of Lectins in Zebrafish

Plant lectins represent a major group of anti-nutritional factors that can be toxic to human and animals. However, the mechanisms by which lectins regulate cell fates are not well-understood. In the present study, the cellular and molecular impacts of three common lectins, agglutinins from wheat germ [wheat germ agglutinin (WGA)], soybean [soybean agglutinin (SBA)], and peanut [peanut agglutinin (PNA)] were examined in zebrafish embryo and liver cells. WGA and SBA were found to induce cell apoptosis both in vitro and in vivo, while PNA stimulated cell proliferation. WGA and SBA reduced levels of B cell lymphoma-2 (Bcl-2), phosphorylation of Bcl-2-associated death promoter (Bad), cyclin-dependent kinase 4 (Cdk4), and phosphorylation of the retinoblastoma (Rb). WGA and SBA also inhibited the activities of cell survival pathways including protein kinase B (Akt), extracellular signal-regulated protein kinases 1 and 2 (Erk1/2), and target of rapamycin (Tor). Furthermore, WGA and SBA shifted the cellular metabolism characterized by reduced expression of glucose-6-phosphate dehydrogenase (g6pd) and increased expression of glutamine synthetase (glul) and glutamate dehydrogenase (glud). However, PNA showed the opposite effects toward these molecular markers compared to those of WGA and SBA. Therefore, our results revealed some plant lectins (WGA and SBA) were toxic while the other (PNA) was mitogenic. Further characterization of the distinct functions of individual lectins should be valuable for both nutrition and other potential applications.

Dietary soybean meal affects intestinal homoeostasis by altering the microbiota, morphology and inflammatory cytokine gene expression in northern snakehead

A 63-day feeding trial was conducted in northern snakehead to observe the effects of a dietary soybean meal substitution on the microbiota community, morphology and inflammatory cytokine gene expression in the intestine. Four isonitrogenous and isoenergetic diets containing increasing levels of soybean meal were used to replace 0%, 25%, 50% and 75% of the defatted fishmeal (diets are referred to G1, G2, G3 and G4, respectively). Different dietary soybean meal substitutions significantly affected the intestinal microbiota composition. At the phylum level, Firmicutes abundance was the lowest in the G4 group, in contrast with Proteobacteria, Bacteroidetes and Planctomycetes. At the genus level, significantly lower abundance of Lactococcus, Geobacillus, Pseudomonas, Streptococcus, Bacillus and Acinetobacter,but higher abundance of Cetobacterium, Planctomyces, Shewanella, Thermomonas, Rubrivivax and Carnobacterium was observed in fish fed the G4 diet. With increased dietary soybean meal, the thickness of the muscularis, the height of the fold and the height of the microvillus in the distal intestine decreased, but the relative expression of IL-1β, IL-10 and IL-17F was significantly up-regulated. In conclusion, more emphasis should be placed on the functionality of intestinal microbiota and the pathogenesis of mucosal inflammation to assess the effects of diet and fish intestinal health through intestinal microbiota profiling.

Effect of feeding soybean meal and differently processed peas on intestinal morphology and functional glucose transport in the small intestine of broilers

Peas are locally grown legumes being rich in protein and starch. However, the broad usage of peas as a feed component in poultry nutrition is limited to anti-nutritional factors, which might impair gut morphology and function. This study investigated the effect of feeding raw or differently processed peas compared with feeding a soybean meal-based control diet (C) on intestinal morphology and nutrient transport in broilers. A total of 360 day-old broiler chicks were fed with one of the following diets: The C diet, and 3 diets containing raw peas (RP), fermented peas (FP) and enzymatically pre-digested peas (EP), each supplying 30% of dietary crude protein. After 35 d, jejunal samples of broilers were taken for analyzing histomorphological parameters, active glucose transport in Ussing chambers and the expression of genes related to glucose absorption, intestinal permeability and cell maturation. Villus length (P = 0.017) and crypt depth (P = 0.009) of EP-fed broilers were shorter compared to birds received C. The villus surface area was larger in broilers fed C compared to those fed with the pea-containing feed (P = 0.005). Glucose transport was higher for broilers fed C in comparison to birds fed with the EP diet (P = 0.044). The sodium-dependent glucose co-transporter 1 (SGLT-1) expression was down-regulated in RP (P = 0.028) and FP (P = 0.015) fed broilers. Correlation analyses show that jejunal villus length negatively correlates with the previously published number of jejunal intraepithelial T cells (P = 0.014) and that jejunal glucose transport was negatively correlated with the occurrence of jejunal intraepithelial leukocytes (P = 0.041). To conclude, the feeding of raw and processed pea containing diets compared to a soybean based diet reduced the jejunal mucosal surface area of broilers, which on average was accompanied by lower glucose transport capacities. These morphological and functional alterations were associated with observed mucosal immune reactions. Further studies are required elucidating the specific components in peas provoking such effects and whether these effects have a beneficial or detrimental impact on gut function and animal health.

Effect of feeding soybean meal and differently processed peas on the gut mucosal immune system of broilers

Peas are traditionally used as a protein source for poultry. However, peas contain antinutritional factors (ANF), which are associated with the initiation of local and systemic immune reactions. The current study examined the effect of feeding raw or differently processed peas in comparison with feeding a soybean meal (SBM) based control diet (C) on the gut mucosal immune system of broilers in a 35 day feeding trial. In six replicates, a total of 360 one-day-old male broilers were randomly allocated to four different groups receiving C, or three treatment diets containing raw, fermented, and enzymatically pre-digested peas, each supplying 30% of required crude protein. After slaughtering, jejunal samples were taken for immunohistochemical, flow cytometric, and gene expression analyses. Investigations were focused on the topological distribution of intraepithelial leukocytes (villus tip, villus mid, and crypt region) as well as on the further characterization of the different intraepithelial lymphocytes (IEL) and concomitant pro- and anti-inflammatory cytokines. Broilers receiving the raw or processed pea diets had higher numbers of intraepithelial CD45+ leukocytes in the tip (P = 0.004) and mid region (P < 0.001) of villi than birds fed C. Higher numbers of intraepithelial CD3+ lymphocytes were found in the villus tip (P = 0.002) and mid region (P = 0.003) of birds fed raw or processed pea containing diets in comparison with those fed C. The flow cytometric phenotyping showed a similar relative distribution of IEL among the feeding groups. The expression of intestinal pro- and anti-inflammatory cytokines was affected by feeding the different diets only to a minor extent. To conclude, feeding of diets formulated with raw and processed peas in comparison with feeding a SBM control diet initiated mucosal immune responses in the jejunum of broilers indicated by a quantitative increase of intraepithelial T cells. Further research is needed in order to ascertain the specific factors which are responsible for observed local immune reactions and how these local reactions might affect the immune status and health of broilers.

Glutamate promotes nucleotide synthesis in the gut and improves availability of soybean meal feed in rainbow trout

Glutamate (Glu) plays various roles directly or through conversions to other amino acids in intracellular metabolisms such as energy source for enterocytes and precursor for nucleic acids. In this study, we examined the effect of single and chronic oral administration of Glu on cell proliferation in intestine and growth in rainbow trout fed soybean meal (SBM) based diet. In the single dose study, 30, 120 and 360 min after oral administration of 50 and 500 mg/kg Glu, the blood and intestine tissues were collected for amino acid concentration and gene expression analysis. Cell-proliferation was detected 24 h after administration using bromo-deoxy uridine (BrdU) in intestine. In the chronic experiment, fish were fed SBM-based diet added 1 and 2 % of Glu for 8 weeks. Final body weight, plasma amino acid concentrations, gene expression and cell-proliferation in the intestine were analyzed. The expressions of some nucleic acid-synthesis related genes were significantly increased 30 min after administration of 50 mg/kg of Glu. After 8 weeks of feeding, the fish fed SBM-based diet showed significantly lower body weight and microvillus thickness in proximal intestine. Supplementation of 2 % of Glu in the SBM-based feed improved both of them. Though it was not significant difference, Glu tended to increase cell-proliferation in the proximal intestine dose-dependently in both single and chronic administration. Our experiment indicates that Glu has positive effect on rainbow trout fed SBM-based feed by reforming proximal intestine through altering cell-proliferation.

The Potential for Engineering Enhanced Functional-Feed Soybeans for Sustainable Aquaculture Feed

Aquaculture is the most rapidly growing segment of global animal production that now surpasses wild-capture fisheries production and is continuing to grow 10% annually. Sustainable aquaculture needs to diminish, and progressively eliminate, its dependence on fishmeal-sourced feed from over-harvested fisheries. Sustainable aquafeed sources will need to be primarily of plant-origin. Soybean is currently the primary global vegetable-origin protein source for aquaculture. Direct exchange of soybean meal for fishmeal in aquafeed has resulted in reduced growth rates due in part to soybean's anti-nutritional proteins. To produce soybeans for use in aquaculture feeds a new conventional line has been bred termed Triple Null by stacking null alleles for the feed-relevant proteins Kunitz Trypsin Inhibitor, lectin, and P34 allergen. Triple Null is now being further enhanced as a platform to build additional transgene traits for vaccines, altered protein composition, and to produce high levels of β-carotene an intrinsic orange-colored aquafeed marker to distinguish the seeds from commodity beans and as the metabolic feedstock precursor of highly valued astaxanthin.

Nutrigenomic profiling of transcriptional processes affected in liver and distal intestine in response to a soybean meal-induced nutritional stress in Atlantic salmon (Salmo salar)

The aim of the present study was to generate an experimental model to characterize the nutrigenomic profile of a plant-derived nutritional stress. Atlantic salmon (Salmo salar) was used as the model species. The nutritional stress was induced by inclusion of dietary defatted soybean meal (SBM), as this ingredient had been previously demonstrated to induce enteropathy in the distal intestine and reduce growth in salmon. Triplicate groups of Atlantic salmon were fed concentrations of 0, 100, 200 and 300 g kg(-1) SBM for 12 weeks and reduced growth performance was used as the indicator of nutritional stress. The transcriptome was analyzed in two tissues, liver and distal intestine, with the hypothesis being that the liver transcriptome would be characterized by gene expression responses related to overall growth and health performance, whereas intestinal gene expression would be dominated by specific responses to SBM. A set of 133 genes was differentially expressed in liver including 44 genes in common with the intestinal response. The liver-specific response included up-regulation of genes involved in protein digestion, energy metabolism and immune functions, whereas genes in other metabolic pathways were generally anabolic and down-regulated. These responses may be more related to general nutritional stress than to SBM per se. The transcriptomic profile in the distal intestine was consistent with the enteritis response as described previously. This study provides a comprehensive report on the profiles of liver and distal intestine transcriptomes, specifically highlighting the role of the liver in fish undergoing SBM-induced nutritional stress.

Effect of fishmeal replacement by soy protein concentrate with taurine supplementation on growth performance, hematological and biochemical status, and liver histology of totoaba juveniles (Totoaba macdonaldi)

The effect of dietary inclusion of soy protein concentrate (SPC) and simultaneous supplementation with taurine on the growth, hematology, blood biochemistry, and liver histology of totoaba (Totoaba macdonaldi) juveniles was assessed. Four isoproteic and isolipidic diets were formulated containing either 30 or 60% of SPC (diets S30 and S60), supplemented or not with 1% of taurine (diets S30T and S60T). A fishmeal-based diet formulated for totoaba nutritional requirements, without SPC and taurine supplementation, was used as a reference diet. Triplicate groups of 32 totoaba juveniles (average body weight 7.5 ± 0.6 g) were fed these diets for 45 days. Results showed that growth performance in fish fed S30, S30T, and S60T was similar to fish fed the reference diet. Red blood cells and hematocrit in fish fed with supplemented taurine in both levels of SPC (S30T and S60T) were similar to the fish fed the RD; the addition of taurine improved the state of hydration of totoaba. Plasmatic hemoglobin in fish fed the lower SPC level was similar to fish fed the RD. The mean corpuscular hemoglobin concentration in fish fed S30T was similar to fish fed the RD, taurine supplementation prevented the development of hypochromic anemia in this group of fish. Plasmatic albumin in fish fed S30 was similar to fish fed the RD. Plasmatic total protein and globulin concentration increased and AL:GLB (albumin:globulin ratio) decreased in fish fed the SPC-based diets despite taurine supplementation. The protein profile showed that taurine supplementation did not prevent a possible inflammatory process (increased globulins, decreased AL:GLB) in juvenile totoaba fed both levels of SPC. Glucose concentration was similar in fish fed S30, S30T, and S60T. The histological hepatic index was highest in fish fed S60. These results suggest that with an appropriate nutritional level, taurine may play an important modulatory role in the hematology and blood biochemistry status in totoaba fed SPC-based diets, contributing to the enhancement of an overall healthy growth performance.

Role of soybean β-conglycinin subunits as potential dietary allergens in piglets

β-Conglycinin, a major seed-storage protein in soybeans, is one of the primary antigenic proteins responsible for soybean-meal hypersensitivity in weaned piglets. The protein is a heterotrimer composed of subunits α, α' and β. It is currently unknown which of the β-conglycinin subunits are allergenic for piglets. The aim of this study was to identify potential allergenic subunits of β-conglycinin for soybean sensitive piglets and to characterise these subunits by immunoglobulin (Ig) G and E immunoblotting, ELISA, 'skin prick' and whole blood histamine-release testing. The IgG and IgE binding capabilities of the purified α, α' and β subunits of β-conglycinin were determined by immunoblot analysis and ELISA with sera from β-conglycinin sensitised piglets. Skin prick testing and whole blood histamine release testing were also performed to detect the activated effector cell response to specific allergens. Specific IgG and E antibodies were identified that recognised all three subunits of β-conglycinin in the sera of β-conglycinin sensitised piglets. All three subunits of β-conglycinin elicited positive skin test and specific histamine release responses from the whole blood of β-conglycinin sensitised piglets. These results suggest that all three β-conglycinin subunits are potential allergens for piglets.

Effect of fishmeal replacement by soy protein concentrate with taurine supplementation on hepatic intermediary metabolism and antioxidant status of totoaba juveniles (Totoaba macdonaldi)

The effect of dietary incorporation of soy protein concentrate (SPC) and the concomitant supplementation with taurine on hepatic intermediary metabolism and antioxidant status of totoaba (Totoaba macdonaldi) juveniles was assessed. Four isoproteic and isolipidic diets were formulated containing either 30 or 60% of SPC (diets SP30 and SP60), supplemented or not with 1% of taurine (diets SP30T and SP60T). A fish meal (FM) based diet, without SPC and taurine supplementation, was used as a control. Triplicate groups of 32 totoaba juveniles (average body mass=7.5g) were fed these diets over 45days. Results revealed that dietary FM replacement by SPC depressed the overall intermediary metabolism. Activity of key enzymes of amino acid catabolism and gluconeogenesis was significantly reduced and a trend to reduce glycolysis and glucose-6-phosphate dehydrogenase activity was observed. The incorporation of the highest level of SPC also significantly increased hepatic lipid peroxidation and the activity of superoxide dismutase. Concomitant taurine supplementation restored the activity of amino acid catabolic and gluconeogenic enzymes and hexokinase to levels similar of those of the control diet. Taurine supplementation also led to a significant increase of glucose-6-phosphate dehydrogenase and catalase activity, as well as to a significant reduction of liver lipid peroxidation. These results suggest that taurine may play an important metabolic modulation action on totoaba fed SPC based diets, contributing to the enhancement of the overall metabolism and to the reduction of liver oxidative damage.

Aquacultured rainbow trout (Oncorhynchus mykiss) possess a large core intestinal microbiota that is resistant to variation in diet and rearing density

As global aquaculture fish production continues to expand, an improved understanding of how environmental factors interact in fish health and production is needed. Significant advances have been made toward economical alternatives to costly fishmeal-based diets, such as grain-based formulations, and toward defining the effect of rearing density on fish health and production. Little research, however, has examined the effects of fishmeal- and grain-based diets in combination with alterations in rearing density. Moreover, it is unknown whether interactions between rearing density and diet impact the composition of the fish intestinal microbiota, which might in turn impact fish health and production. We fed aquacultured adult rainbow trout (Oncorhynchus mykiss) fishmeal- or grain-based diets, reared them under high- or low-density conditions for 10 months in a single aquaculture facility, and evaluated individual fish growth, production, fin indices, and intestinal microbiota composition using 16S rRNA gene sequencing. We found that the intestinal microbiotas were dominated by a shared core microbiota consisting of 52 bacterial lineages observed across all individuals, diets, and rearing densities. Variations in diet and rearing density resulted in only minor changes in intestinal microbiota composition despite significant effects of these variables on fish growth, performance, fillet quality, and welfare. Significant interactions between diet and rearing density were observed only in evaluations of fin indices and the relative abundance of the bacterial genus Staphylococcus. These results demonstrate that aquacultured rainbow trout can achieve remarkable consistency in intestinal microbiota composition and suggest the possibility of developing novel aquaculture strategies without overtly altering intestinal microbiota composition.

Soybean β-conglycinin induces inflammation and oxidation and causes dysfunction of intestinal digestion and absorption in fish

β-Conglycinin has been identified as one of the major feed allergens. However, studies of β-conglycinin on fish are scarce. This study investigated the effects of β-conglycinin on the growth, digestive and absorptive ability, inflammatory response, oxidative status and gene expression of juvenile Jian carp (Cyprinus carpio var. Jian) in vivo and their enterocytes in vitro. The results indicated that the specific growth rate (SGR), feed intake, and feed efficiency were reduced by β-conglycinin. In addition, activities of trypsin, chymotrypsin, lipase, creatine kinase, Na(+),K(+)-ATPase and alkaline phosphatase in the intestine showed similar tendencies. The protein content of the hepatopancreas and intestines, and the weight and length of the intestines were all reduced by β-conglycinin. β-Conglycinin increased lipid and protein oxidation in the detected tissues and cells. However, β-conglycinin decreased superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione peroxidase (GPx) and glutathione reductase (GR) activities and glutathione (GSH) content in the intestine and enterocytes. Similar antioxidant activity in the hepatopancreas was observed, except for GST. The expression of target of rapamycin (TOR) gene was reduced by β-conglycinin. Furthermore, mRNA levels of interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and transforming growth factor-β (TGF-β) genes were increased by β-conglycinin. However, β-conglycinin increased CuZnSOD, MnSOD, CAT, and GPx1b gene expression. In conclusion, this study indicates that β-conglycinin induces inflammation and oxidation, and causes dysfunction of intestinal digestion and absorption in fish, and finally reduces fish growth. The results of this study provide some information to the mechanism of β-conglycinin-induced negative effects.

Transcriptional regulation of IL-17A and other inflammatory markers during the development of soybean meal-induced enteropathy in the distal intestine of Atlantic salmon (Salmo salar L.)

Progression of soybean meal (SBM)-induced enteropathy in Atlantic salmon (Salmo salar L.) distal intestine (DI) was studied to investigate pathophysiological mechanisms and immune responses. Seawater-adapted salmon were fed an extracted SBM-containing diet (200 g kg(-1)) from day 1-21 and compared with fish fed a fishmeal-based diet (day 0). Histological evaluation of the DI revealed signs of inflammation from day 5, which progressively increased in severity and affected more fish with increasing SBM exposure time. The expression profiles of 16 genes were analyzed by quantitative PCR. The pro-inflammatory cytokines interleukin 17A (IL-17A), IL-1β, interferon α (IFNα) and IFNγ, as well as IL-17A receptor, T-cell receptor γ (TCRγ), cluster of differentiation 4α (CD4α), CD8β, transforming growth factor β (TGFβ), trypsin, protease-activated receptor 2 (PAR2) and myeloid differentiation primary response gene 88 (MyD88) were significantly up-regulated during early and/or late inflammation stages, whereas interferon-γ-inducible lysosomal thiol reductase (GILT) was downregulated. Up-regulation of TCRγ from day seven suggests proliferation of intraepithelial γδ T cells. IL-17A, up-regulated by 218-fold during early inflammation, indicates involvement of T helper 17 cells in the pathogenesis of the SBM-induced inflammatory response.

High-yield expression of recombinant soybean agglutinin in plants using transient and stable systems

Soybean agglutinin (SBA) is a specific N-acetylgalactosamine-binding plant lectin that can agglutinate a wide variety of cells. SBA has great potential for medical and biotechnology-focused applications, including screening and treatment of breast cancer, isolation of fetal cells from maternal blood for genetic screening, the possibility as a carrier system for oral drug delivery, and utilization as an affinity tag for high-quality purification of tagged proteins. The success of these applications, to a large degree, critically depends on the development of a highly efficient expression system for a source of recombinant SBA (rSBA). Here, we demonstrate the utility of transient and stable expression systems in Nicotiana benthamiana and potato, respectively, for the production of rSBA, with the transgenic protein accumulated to 4% of total soluble protein (TSP) in Nicotiana benthamiana leaves and 0.3% of TSP in potato tubers. Furthermore, we show that both plant-derived rSBAs retain their ability to induce the agglutination of red blood cells, are similarly glycosylated when compared with native SBA, retained their binding specificity for N-acetylgalactosamine, and were highly resistant to degradation in simulated gastric and intestinal fluids. Affinity column purification using N-acetylgalactosamine as a specific ligand resulted in high recovery and purity of rSBA. This work is the first step toward use of rSBA for various new applications, including the development of rSBA as a novel affinity tag for simplified purification of tagged proteins and as a new carrier molecule for delivery of oral drugs.

Time-related changes of the intestinal morphology of Atlantic salmon, Salmo salar L., at two different soybean meal inclusion levels

Abstract Soybean meal (SBM) induces enteritis in the distal intestine of Atlantic salmon. The present study assesses the effects of SBM concentrations on the kinetics of the enteritis process. Fish of 300 g, kept at 12 degrees C, were fed diets with different SBM inclusions: 0%, 10% and 20% SBM for 57 days. Samples of the distal intestine of five fish per treatment were taken for histological and electron microscopical analysis. A semi-quantitative scoring system was used to assess the degree of the morphological changes induced by SBM feeding in the distal intestinal epithelium. The first signs of enteritis appeared earlier in the salmon fed the 20SBM diet than in those fed the 10SBM diet. Thereafter, the condition increased steadily, displaying no signs of recovery. Furthermore, at the lower concentration, the process marking the onset of enteritis began more gradually than at the higher concentration and it displayed a tendency to stabilize after 13-20 days of continuous feeding. Electron microscopy indicated that the endocytosis process was hampered at day 3 of 20SBM and at 7 days of 10SBM. Furthermore, a strong reduction of microvilli was already evident after 7 days of 20SBM feeding, thus indicating a decreased uptake capacity of the distal enterocytes. In addition, transformation and migration of eosinophilic granulocytes was observed, which, in combination with the lysozyme C immunoreactivity supports their protective role during the inflammatory process in the distal gut of Atlantic salmon. It can be concluded that the severity of enteritis and its kinetics are concentration-dependent, showing no signs of recovery during feeding with diets containing SBM.

Batch and bulk removal of a triarylmethane dye, Fast Green FCF, from wastewater by adsorption over waste materials

De-Oiled Soya, an agricultural waste material and Bottom Ash a waste of power plants, have been used as adsorbents for the removal and recovery of a triarylmethane dye Fast Green FCF from wastewater. Batch studies have been carried by observing the effects of pH, temperature, concentration of the dye, amount of adsorbents, sieve size of adsorbent, contact time, etc. Graphical correlation of various adsorption isotherm models like, Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich have been carried out for both the adsorbents. The adsorption over both the materials has been found endothermic and feasible in nature. Various thermodynamic parameters, such as, Gibb's free energy, entropy and enthalpy of the on-going adsorption process have been calculated. The kinetic studies suggest the process following pseudo first order kinetics and involvement of particle diffusion mechanism. The bulk removal of the dye has been carried out by passing the dye solution through columns of Bottom Ash and De-Oiled Soya and saturation factor of each column has been calculated. Attempts have also been made to recover the dye by eluting dilute NaOH through the columns.

Soybean meal induces intestinal inflammation in common carp (Cyprinus carpio L.)

The development of soybean meal (SBM) induced enteritis in the hindgut of the omnivorous common carp (Cyprinus carpio L.). The developed condition was assessed when carp, continuously fed on animal protein, were transferred to a diet in which 20% of the protein was replaced by SBM. After week 1, most of the inflammation parameters were already present, but at week 3, a strong aggravation of the condition was observed which included a shortening of the mucosal folds, the disappearance of the supranuclear vacuoles, an increased number of goblet cells, a thickened lamina propria and sub-epithelial mucosa with increased numbers of basophilic granulocytes as well as a decreased uptake capacity of enterocytes (impaired endocytosis and microvilli). Contrary to previous observations made with respect to Atlantic salmon, common carp start to recover from the fourth to the fifth week after switching to SBM feeding. At this stage, the supranuclear vacuoles refill and most of the parameters revert to basal levels. During the enteritis process, a real-time quantitative PCR analysis was conducted to measure the expression of inflammatory and anti-inflammatory cytokine genes in the isolated intraepithelial lymphocytes (IEL). The pro-inflammatory interleukin 1 beta (IL-1 beta) and tumour necrosis factor alpha1 (TNF-alpha1) genes were up-regulated during the inflammation process while the anti-inflammatory interleukin 10 (IL-10) was down-regulated after an initial up-regulation at week 1. Transforming growth factor beta (TGF-beta) expression showed an up-regulation from week 3 onwards despite the high Ct value and the low primer efficiency shown. This study confirms the contribution of IEL (mainly T-like cells) and basophils in the enteritis process. In addition, the results show a clear involvement of up- and down-regulated cytokine genes in both the onset and recovery of the SBM-induced enteritis in the hindgut of carp.

Process development for the batch and bulk removal and recovery of a hazardous, water-soluble azo dye (Metanil Yellow) by adsorption over waste materials (Bottom Ash and De-Oiled Soya)

Bottom Ash and De-Oiled Soya have been used as adsorbents for the removal of a hazardous azo dye-Metanil Yellow from its aqueous solutions. Adsorption of Metanil Yellow on these adsorbents has been studied as function of time, temperature, concentration and pH. Batch adsorption studies, kinetic studies and column operations enabled extraction of lethal dye from wastewaters. Adsorption equilibrium data confirms both Langmuir and Freundlich isotherm models and monolayer coverage of dye over adsorbents. Kinetic data have been employed to calculate specific rate constants, indicating thereby involvement of first order kinetics in the on-going adsorption and activation energy was determined as 0.813 and 1.060 kJ mol(-1) for Bottom Ash and De-Oiled Soya, respectively. For both adsorbents, the adsorption process has been found governing by film diffusion, over the entire concentration range. Column operations have also been performed for the bulk removal of the dye and also to examine the practical utilization of fixed bed adsorption technique in elimination of dangerous effluent. Saturation factors for Bottom Ash and De-Oiled Soya columns have been calculated as 99.15 and 99.38%, respectively. Attempts have also been made to regenerate the dye from the exhausted columns using aqueous sodium hydroxide as eluent.