Trypsin Activity Research Articles

Beneficial effects of oleanolic acid on hepatopancreas oxidative stress and intestinal microbiota structure of red swamp crayfish (Procambarus clarkia)

This study aimed to evaluate the beneficial effects of oleanolic acid (OA) in the culture of red swamp crayfish (Procambarus clarkia) by investigating the impact of dietary OA on growth performance, hepatopancreas antioxidant activity, innate immunity, and intestinal microbiota structure. An eight-week feeding trial was conducted using different dietary OA concentrations: 0, 250, 500, 750, and 1000 mg·kg–1. The results revealed that the groups with 500–1000 mg·kg–1 OA exhibited increased final body weight, weight gain rate, and specific growth rate, as well as decreased feed conversion ratio compared to those in the control group (P < 0.05). Serum alanine transaminase (ALT) and aspartate transaminase (AST) activities showed a linear decrease with increasing dietary OA concentration. OA demonstrated hypolipidemic effects by reducing serum glucose, total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels, while increasing serum high-density lipoprotein cholesterol levels (P < 0.05). OA500 to OA1000 groups exhibited significantly higher trypsin activity compared to that of the control, while lipase activity linearly decreased with increasing dietary OA concentration. The antioxidant capacity, as indicated by glutathione level in the hepatopancreas, showed significant differences between the OA treatment group and the control group. However, dietary OA did not significantly alter the structure of the intestinal microbiota. These findings suggest that dietary OA supplementation effectively improves the growth performance and enhanced the innate immunity of crayfish. Furthermore, OA significantly promotes the antioxidant capacity, thereby protecting the hepatopancreas from oxidative damage. The optimal dose range of dietary OA for application in crustacean culture is recommended to be between 500 and 1000 mg·kg−1.

Partial Substitution of Whey Protein Concentrate with Spray–Dried Porcine Plasma or Soy Protein Isolate in Milk Replacer Differentially Modulates Ileal Morphology, Nutrient Digestion, Immunity and Intestinal Microbiota of Neonatal Piglets

Appropriate protein sources are vital for the growth, development and health of neonates. Twenty–four 2–day–old piglets were randomly divided into three groups and fed isoenergetic and isonitrogenous diets. The experimental diets included a milk replacer with 17.70% whey protein concentrate (WPC group), a milk replacer with 6% spray–dried porcine plasma isonitrogenously substituting WPC (SDPP group), and a milk replacer with 5.13% soy protein isolate isonitrogenously substituting WPC (SPI group). Neonatal piglets were fed milk replacer from postnatal day 2 (PND 2) to day 20 (PND 20). The growth performance, intestinal morphology, activities of digestive enzymes, plasma biochemical parameters, immunity–related genes, short–chain fatty acids (SCFA) and intestinal microbiota in the colonic chyme were determined. The results showed that SDPP–fed piglets had higher final BW (p = 0.05), ADG (p = 0.05) and F/G (p = 0.07) compared with WPC– and SPI–fed piglets, and SDPP–fed piglets had a lower diarrhea index (p &lt; 0.01) from PND 2 to PND 8. SDPP–fed piglets had an increased ileal villus height (p = 0.04) and ratio of villus height to crypt depth (VCR) (p = 0.02), and increased activities of sucrase (p &lt; 0.01), lactase (p = 0.02) and trypsin (p = 0.08) in the jejunum, compared with WPC– and SPI–fed piglets. Furthermore, SPI–fed piglets had an increased mRNA expression of IL-6 (p &lt; 0.01) and concentration of plasma urea (p = 0.08). The results from LEfSe analysis showed that SDPP–fed piglets had a higher abundance of beneficial Butyricicoccus compared with WPC– and SPI–fed piglets, in which higher abundances of pathogenic bacteria such as Marinifilaceae, Fusobacterium and Enterococcus were observed. Moreover, SDPP–fed piglets had an increased concentration of butyric acid (p = 0.08) in the colonic chyme compared with WPC– and SPI–fed piglets. These results suggest that neonatal piglets fed milk replacer with SDPP partially substituting WPC had improved growth performance and intestinal morphology and function, associated with higher digestive enzyme activity and fewer pathogenic bacteria.

Optimization of weaning age for striped murrel (Channa striata) based on expression and activity of proteases

The pattern of gene expression and the activity of three proteases – trypsin, chymotrypsin, and pepsin – were investigated from yolk sac stage to 35 days post hatching (dph) in larvae and juveniles of striped murrel (Channa striata), a high-value fish species with a great potential for aquaculture. The mRNA expression level of trypsin increased from 3 dph onwards and concurrently with absorption of the yolk sac, peaking at 12 dph and 25 dph (p < 0.05). Chymotrypsin expression peaked at 21 dph. In pepsin, mRNA levels were not detectable from hatching to 3 dph but increased significantly at 25 dph (p < 0.05). Maximum specific activity of trypsin was observed at 18 dph, while chymotrypsin showed significantly higher (p˂0.05) activity at 21 dph. Specific activity of pepsin increased from 18 dph onwards and peaked at 30 dph. These patterns suggest that larvae/juveniles of C. striata are best weaned between 18 dph and 25 dph to coincide with functional development of the exocrine pancreas and stomach.

Effects of Mulberry Leaf Extract on the Liver Function of Juvenile Spotted Sea Bass (Lateolabrax maculatus).

In order to explore the effect of mulberry leaf extract (ELM) on the liver function of spotted sea bass, 360 fish with healthy constitution (average body weight 9.00 ± 0.02 g) were selected and randomly divided into six groups with three repetitions, and six groups of fish were randomly placed into 18 test tanks (200 L) with 20 fish per tank for the 52-day feeding test. Every day, the fish were fed the experimental feed with different concentrations (0, 3, 6, 9, 12, 15 g/kg) to the level of apparent satiation, with a crude protein content of 48.0% and a crude fat content of 8.6%. And the water temperature was maintained at 25-28°C with a salinity of 0.5%-1‰. After feeding, five fish were randomly selected to collect their livers and serum for detection of indicators. The results showed that, compared with the control group, ELM significantly increased the activities of lipase (LPS) and trypsin (TRS) in the liver, and reached the highest level when the amount of ELM added was 6 g/kg (P < 0.05). ELM significantly increased the activities of lactate dehydrogenase (LDH) and glutamic-oxaloacetic transaminase (GOT) involved in the metabolic process in liver tissue, and GOT activity reached the highest when ELM was added at 9 g/kg, and LDH activity reached the highest when ELM was added at 15 g/kg (P < 0.05). ELM had no significant effect on liver antioxidant enzymes (P > 0.05), but the content of malondialdehyde was significantly reduced (P < 0.05). Compared with the control group, ELM significantly increased the activities of AKP and ACP in the liver, and the AKP activity reached the highest when the ELM addition amount was 3 g/kg, and the ACP activity reached the highest when the ELM addition amount was 9 g/kg (P < 0.05). Through comparative transcriptomic analysis, it was indicated that ELM enhanced the hepatic lipids and carbohydrates metabolism ability, as manifested in the upregulation of expression of phosphatidate phosphatase, glucuronosyltransferase, inositol oxygenase, carbonic anhydrase, and cytochrome c oxidase subunit 2. ELM can also increase the expression of signal transducer and activator of transcription 1, ATP-dependent RNA helicase and C-X-C motif chemokine 9 involved in the immune process. The above results show that the ELM can enhance the digestion, metabolism, and immunity of the liver by increasing the activity of digestive enzymes, metabolic enzymes, and the expression of metabolism and immune regulation genes. This study provides a theoretical basis for the application of ELM in the cultivation of spotted sea bass by exploring the effect of ELM on the liver function of spotted sea bass.

Larval digestive system ontogeny and early weaning in neon tetra Paracheirodon innesi.

The intensive culture of characid teleosts for ornamental trade is highly dependent on live feed organisms, particularly Artemia nauplii, to provide nutrition through the larval stage. Live feeds have inherent disadvantages relative to prepared microparticulate diets (MDs), specifically availability, labor and cost. In this research, the dependence of larval Paracheirodon innesi on live Artemia was confirmed via a nutritional trial. Next, digestive system ontogeny was characterized from the onset of exogenous feeding through metamorphosis. P. innesi exhibited an agastric larval stage, as well as low digestive enzyme activity at the onset of exogenous feeding followed by abrupt increases in trypsin, lipase and pepsin activity. Differentiation of the stomach, including gastric gland formation and production of neutral mucopolysaccharides, as well as the onset of pepsin activity, did not occur until 20days post hatch (dph; 5.24 ± 0.20mm). This shift from agastric to gastric digestive modes is indicative of a proliferation of digestive capacity and subsequent prey diversity in other fish species exhibiting similar altricial larval stages.Based on this information, different schedules for weaning from Artemia to a MD were evaluated. For P. innesi fed until 32 dph, weaning beginning at 12 dph and 17 dph resulted in similar survival to live Artemia (mean: 22.0 ± 1.7%), and the MD resulted in the lowest survival (0.8 ± 0.3%). These results indicate that weaning is possible prior to gastric differentiation, potentially resulting in the reduction of Artemia use in the larval culture P. innesi.

Investigation of the Impact of Saccharides on the Relative Activity of Trypsin and Catalase after Droplet and Spray Drying.

While using saccharides as stabilizers for therapeutic protein drying is common, the mechanisms underlying the stabilization during drying remain largely unexplored. Herein, we investigated the effect of different saccharides, trehalose dihydrate (TD), dextran (DEX), and hydroxypropyl β-cyclodextrins (low substitution-HP and high substitution-HPB), on the relative activities of the enzymes trypsin and catalase during miniaturized drying (MD) or spray drying (SD). For trypsin, the presence of saccharides, especially HP, was beneficial, as it significantly improved the enzyme activity following MD. The HPB preserved trypsin's activity during MD and SD. Adding saccharides during MD did not show a notable improvement in catalase activities. Increasing TD was beneficial during the SD of catalase, as indicated by significantly increased activity. Molecular docking and molecular dynamics simulations oftrypsin with HP or HPB revealed the influence of their substitution on the binding affinity for the enzyme. A higher affinity of HP to bind trypsin and itself was observed during simulations. Experimentally, activity reduction was mainly observed during MD, attributable to the higher droplet temperature during MD than during SD. The activities from the experiments and aggregation propensity from molecular modeling helped elucidate the impact of the size of protein and saccharides on preserving the activity during drying.

Optimal dietary protein level for the growth and metamorphosis of bullfrog (Lithobates catesbeianus) tadpoles

This study investigated the effects of dietary protein levels on growth performance, antioxidant capacity, digestive enzyme activity, and metamorphosis rate of the bullfrog (Lithobates catesbeianus) tadpoles. Seven isolipidic and isoenergetic diets were formulated with 24.61%, 28.49%, 33.74%, 37.50%, 44.06%, 48.39% and 53.92% crude protein. Triplicate replicates of tadpoles (growth stage 25 and 0.009 g) were fed with experimental diets two times daily for 11 weeks, and the daily feeding amount was 6.50% of the tadpole's body weight. Weight gain (WG), specific growth rate (SGR), the total antioxidant capacity (T-AOC) and catalase (CAT) activity in the liver, the intestinal trypsin activity (TPS) and metamorphosis rate at stage 42 of bullfrog tadpoles all increased with increasing dietary protein level from 24.61% to 44.06% and then decreased. Based on the second-order polynomial regression analysis of the weight gain and metamorphosis rate at stage 41 vs. dietary protein level, the optimal dietary protein level for bullfrog tadpoles was 42.49% and 46.50%, respectively. In conclusion, the optimum dietary protein level of bullfrog tadpoles was estimated to be 42.49%–46.50% of the diet.

Dietary sodium benzoate improves growth, morphology, antioxidant capacity and resistance against Aeromonas hydrophila of Pacific white shrimp (Litopenaeus vannamei)

Acidifier has become one of the most important substitutes for antibiotics, and its beneficial effects on growth performance and digestive ability have been evidenced. Sodium benzoate is a commonly used acidifier. A 56-day feeding test was carried out to elucidate the effects of dietary sodium benzoate on growth performance, morphology, antioxidant activity and intestinal microflora of juvenile Litopenaeus vannamei with an average initial body weight of 0.55 ± 0.01 g. Six experimental diets were prepared by adding 0, 750, 1000, 1250, 1500 and 1750 mg/kg sodium benzoate to the control diet. The results showed that: The final body weight (FBW) and weight gain (WG) of juvenile shrimp were significantly improved by diet supplemented with 1750 mg/kg sodium benzoate. Dietary 1750 mg/kg sodium benzoate significantly increased the trypsin activity. The activities of catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST) in the intestine and hepatopancreas of the 1750 mg/kg sodium benzoate group were markedly higher than those of the control group. Furthermore, the expression levels of trypsin (TRY), amylase (AMS), lysozyme (LZM), interleukin-8 (IL8) and interleukin-10 (IL10) genes in the intestine significantly increased when the content of sodium benzoate in the diet was greater than or equal to 1000 mg/kg. The addition of 1500 and 1750 mg/kg sodium benzoate to the feed improved the intestinal and hepatopancreatic tissue structures of juvenile shrimp and enriched the diversity of intestinal microbiota. Sodium benzoate residues were not detected in each sodium benzoate supplemented group. At the end of the Aeromonas hydrophila challenge test, juvenile shrimp in the 1500 and 1750 mg/kg group exhibited significantly higher cumulative survival rates than that in the control group. Conclusively, dietary 1750 mg/kg sodium benzoate could improve the growth performance, antioxidant capacity, morphology, intestinal microflora and disease resistance of juvenile shrimp.

Metformin inhibits digestive proteases and impairs protein digestion in mice

Metformin is among the most prescribed medications worldwide and the first-line therapy for type 2 diabetes. However, gastrointestinal side effects are common and can be dose limiting. The total daily metformin dose frequently reaches several grams, and poor absorption results in high intestinal drug concentrations. Here, we report that metformin inhibits the activity of enteropeptidase and other digestive enzymes at drug concentrations predicted to occur in the human duodenum. Treatment of mouse gastrointestinal tissue with metformin reduces enteropeptidase activity; further, metformin-treated mice exhibit reduced enteropeptidase activity, reduced trypsin activity, and impaired protein digestion within the intestinal lumen. These results indicate that metformin-induced protein maldigestion could contribute to the gastrointestinal side effects and other impacts of this widely used drug.

Effects of replacing fish meal with a blend of corn gluten meal and meat meal on the growth, biochemical profile, digestive enzyme activity, antioxidant status, and innate immunity of juvenile black rockfish (Sebastes schlegelii)

This study assessed the impact of replacing fish meal (FM) with a blend of corn gluten meal and meat meal (BCM) at a ratio of 1:2 on the growth performance, digestive enzyme activity, and nonspecific immune response of juvenile black rockfish (Sebastes schlegelii). Seven experimental diets were formulated. The control (BCM0) diet contained 65% FM. Subsequently, 10, 20, 30, 40, 50, and 60% FM in BCM0 diet were replaced with BCM, referred to as the BCM10, BCM20, BCM30, BCM40, BCM50 and BCM60, respectively. Each diet was randomly assigned to triplicate groups of 30 rockfish (initial body weight: 3.6 ± 0.01 g) for 8 weeks. The BCM0–BCM50 diets resulted in no significant differences in final body weight (FBW), weight gain (WG), and specific growth rate (SGR), whereas the BCM60 diet led to the lowest FBW, WG, and SGR. The feed consumption and feed efficiency of rockfish fed BCM10–BCM50 diets did not differ significantly from those of rockfish fed the BCM0 diet. Intestinal trypsin and lipase activities showed a linear decrease with increasing substitution levels of BCM in the experimental diets. Moisture levels increased with elevated BCM replacement in diets, whereas crude protein and lipid levels decreased with increased BCM replacement. Whole-body amino acid profiles of rockfish, except for glycine and proline content, were not significantly affected by diet. However, lysozyme and catalase activities exhibited quadratic responses to increasing dietary BCM levels, and superoxide dismutase activity and glutathione content showed a negative linear response. Overall, these results show that a blend of corn gluten meal and meat meal can replace up to 50% of dietary FM without adversely affecting the growth performance of juvenile rockfish.

Effects of dietary thiamin (vitamin B1) on the growth performance, serum biochemical factors, immune response, and antioxidant activity of great sturgeon (Huso huso) juveniles.

The present research evaluated the positive effects of dietary thiamin (vitamin B1) levels on the growth performance, serum biochemistry factors, immune response, and antioxidant activity of great sturgeon (Huso huso) juveniles. Thiamin was included in diets with levels of 0 (control, T0), 7 (T7), 15 (T15), and 25 (T25) mg/kg diet. Measurements of thiamin levels in diets indicated that they contained 1.80 (T0), 8.02 (T7), 16.2 (T15), and 26.6 (T25) mg thiamin/kg feed. Sturgeon juveniles (240 individuals) with average weight of 44.8 ± 1.96g were distributed into 12 tanks, and fed with the experimental diets for 8 weeks. Final weight, body weight gain (%), specific growth rate, and feed conversion ratio (FCR) of great sturgeon were significantly influenced by dietary thiamin levels, and the maximum fish performance (P < 0.05) was obtained at a level of 15mg/kg diet. The trypsin, chymotrypsin, creatine kinase, lipase, α-amylase, and alkaline phosphatase activities were notably (P < 0.05) affected by the dietary thiamin levels. The glucose content was not significantly (P > 0.05) different among the experimental treatments. Diets supplemented with thiamine increased significantly (P < 0.05) triglyceride, cholesterol, and total protein levels accompanied with significant (P < 0.05) decreases in aminotransferase aspartate and alanine aminotransferase activities. Serum antioxidant enzymes were remarkably (P < 0.05) higher, while serum malondialdehyde was significantly (P < 0.05) lower in the thiamin-treated fish compared with the control group. Total immunoglobulin, lysozyme, and ACH50 values were significantly (P < 0.05) higher in fish fed with thiamin-supplemented diets than in the control group. The results of the present study demonstrated that dietary thiamin have an important role in enhancing the growth performance, immune response, and antioxidant activity of great sturgeon. Based on the regression fitting curve of final weight, weight gain, specific growth rate, and FCR values, the optimal level of thiamin is found to be 15.0-17.5mg/kg diet.

Lactobacillus plantarum E2 regulates intestinal microbiota and alleviates Pseudomonas plecoglossicida induced inflammation and apoptosis in zebrafish (Danio rerio)

Pseudomonas plecoglossicida infection is a highly contagious epidemic in aquaculture, causing significant mortality among teleost. Our previous research has demonstrated that Lactobacillus plantarum E2 is beneficial for large yellow croaker in resisting infections caused by P. plecoglossicida. However, the relevant mechanisms remain largely unclear. In the present study, we used zebrafish (Danio rerio) to further explore the function of L. plantarum E2 and its mechanisms for resisting P. plecoglossicida infection. E2 supplementation diet significantly improved the growth rates and α-amylase and trypsin activities of the liver in zebrafish. After challenge with P. plecoglossicida strain PQLYC4, the survival rates of zebrafish were improved, and immune-related genes expression (IL-1β, TNF-α, IL-8, Ig-Z, TLR-22 and IL-12α) were down-regulated. Histological analysis showed that E2 group had a longer intestinal villus and thicker intestinal walls after 30 days of feeding and healthier intestinal structure after challenge with P. plecoglossicida strain PQLYC4. Furthermore, co-incubation of zebrafish embryo fibroblast (ZF-4 cells) with L. plantarum E2 reduced apoptosis of ZF-4 cells after exposed to P. plecoglossicida. Intestinal microbiota analysis showed that E2 strain significantly increased the relative abundance of Lactobacillus and Pseudomonas, and PCoA analysis revealed a noticeable divergence in the intestinal microbial communities after E2 supplement. Together, our results suggested that E2 strain may promote zebrafish survival against P. plecoglossicida infection by regulating the intestinal microbiota and alleviating inflammatory response and apoptosis, thus exhibiting the potential as a probiotic.

Enhanced expression of a novel trypsin from Streptomyces fradiae in Komagataella phaffii GS115 through combinational strategies of propeptide engineering and self-degredation sites modification

This study aimed to enhance the expression level of a novel trypsin gene from Streptomyces fradiae ATCC14544 in Komagataella phaffii GS115 through the combinational use of propeptide engineering and self-degradation residues modification strategies. An artificial propeptide consisted of thioredoxin TrxA, the bovine propeptide DDDDK and the hydrophobic peptide FVEF was introduced to replace the original propeptide while the self-degradation residue sites were predicted and analyzed through alanine screening. The results showed that the quantity and enzymatic activity of asft with engineered propeptide reached 47.02 mg/mL and 33.9 U/mL, which were 9.6 % and 59.29 % higher than those of wild-type (42.9 mg/mL and 13.8 U/mL). Moreover, the introduction of R295A/R315A mutation further enhanced the enzymatic activity (58.86 U/mL) and obviously alleviated the phenomena of self-degradation. The tolerance of trypsin towards alkaline environment was also improved since the optimal pH was shifted from pH 9.0 to pH 9.5 and the half-life value at pH 10 was significantly extended. Finally, the fermentation media composition and condition were optimized and trypsin activity in optimal condition reached 160.58 U/mL, which was 2.73-fold and 11.64-fold of that before optimization or before engineering. The results obtained in this study indicated that the combinational use of propeptide engineering and self-degradation sites modification might have great potential application in production of active trypsins.

Duodenal-ileal ratio of digestive enzymes when using different protein supplements in the diet of laying hens

Creation of domestic poultry crosses and development of optimal diets for them is an urgent problem, since in vivo studies using fistula technologies are currently few. The present work presents data on determination of duodenal and ileal activity of digestive enzymes when protein additives of vegetable (soybean meal and cake) and animal origin (fish meal and meat and bone meal) are used in the diet of laying hens. Experiments were performed on laying hens (Gallus gallus L.) of Hisex White cross (n=24, K.A. Timiryazev Russian State Agricultural Academy, 2022,2023) with chronic duodenal and ileal fistula. All chickens were divided by random sampling method into 4 groups: 1) 1 control group - received OR (Table 1); 2) 2 experimental group - 1.5% soybean cake was added to the diet instead of soybean meal; 3) 3 experimental group - 1.5% meat and bone meal was added to the diet instead of soybean meal; 4) 4 experimental group - 1.0% fish meal was added to the OR instead of soybean meal. It was found that protein additives are differently hydrolyzed in the intestine of birds and assimilated by the organism. Thus, the breakdown of soy protein is more intensive in cake than in meal due to the increase of trypsin activity in duodenum by 43.6%, and when fish meal is added, the activity of the enzyme increases by 11.8% against meat and bone meal and 101.5% against soy meal. At the same time, protein digestion increased, accompanied by an increase in trypsin activity in blood when soybean cake was used and in urine when fish meal was added to the diet of chickens. With feces the least loss of trypsin is observed in the group that received meat and bone meal supplementation (9.6% of trypsin activity is excreted), then fish meal - 16.8% and soy cake - 21.7% of activity in duodenum, which indicates the efficiency of exo- and endogenous protein utilization by poultry organism.

Oral vancomycin treatment suppresses gut trypsin activity and preserves intestinal barrier function during EAE

Studies have reported increased intestinal permeability in multiple sclerosis (MS) patients and its mouse model experimental autoimmune encephalomyelitis (EAE). However, the mechanisms driving increased intestinal permeability that in turn exacerbate neuroinflammation during EAE remain unclear. Here we showed that vancomycin preserved the integrity of the intestinal barrier, while also suppressing gut trypsin activity, enhancing the relative abundance of specific Lactobacilli and ameliorating disease during EAE. Furthermore, Lactobacilli enriched in the gut of vancomycin-treated EAE mice at day 3 post immunization negatively correlated with gut trypsin activity and EAE severity. In untreated EAE mice, we observed increased intestinal permeability and increased intestinal protease activated receptor 2 (PAR2) expression at day 3 post immunization. Prior studies have shown that trypsin increases intestinal permeability by activating PAR2. Our results suggest that the interaction between intestinal PAR2 and trypsin may be a key modulator of intestinal permeability and disease severity during EAE.

Supplementation of grape seed extract improves the gastrointestinal development of weaned beef calves

This experiment evaluated the potential benefits of grape seed extract (GSE) supplementation on digestive enzyme activity, gastrointestinal morphology and barrier function of weaned beef calves. A total of 30 Simmental crossbred male calves with similar age (68 ± 6 d) and body weight (83.47 ± 4.59 kg) were randomly assigned to 2 groups: control (CON) (fed basal diet) and GSE (fed basal diet and 4 g/d GSE per animal). The experimental period was 60 d. Compared with CON group, the serum diamine oxidase and lipopolysaccharide concentrations in GSE group were reduced (P < 0.05), while the activity of ruminal cellulase and ileal trypsin and chymotrypsin displayed an opposite pattern (P < 0.05) between the groups. The ruminal papilla height and surface area of GSE group were higher (P < 0.05) than those of CON group. A similar pattern of ileal villus surface area and villus-to-crypt ratio was observed between the groups. Also, GSE supplementation increased (P < 0.05) the secretory immunoglobulin A content in the jejunum and ileum. The rumen, jejunum and ileum of GSE calves displayed lower (P < 0.05) tumor necrosis factor-alpha and higher (P < 0.05) interleukin-10 mRNA expressions. Calves supplemented with GSE increased (P < 0.05) the expressions of occludin and zonula occludens-1 in the rumen and ileum. The findings in this study suggested that GSE improved the gastrointestinal development of weaned beef calves.

Nanoscale ZnO Improves the Amino Acids and Lipids in Tomato Fruits and the Subsequent Assimilation in a Simulated Human Gastrointestinal Tract Model.

With the widespread use of nanoenabled agrochemicals, it is essential to evaluate the food safety of nanomaterials (NMs)-treated vegetable crops in full life cycle studies as well as their potential impacts on human health. Tomato seedlings were foliarly sprayed with 50 mg/L ZnO NMs, including ZnO quantum dots (QDs) and ZnO nanoparticles once per week over 11 weeks. The foliar sprayed ZnO QDs increased fruit dry weight and yield per plant by 39.1% and 24.9, respectively. It also significantly increased the lycopene, amino acids, Zn, B, and Fe in tomato fruits by 40.5%, 15.1%, 44.5%, 76.2%, and 12.8%, respectively. The tomato fruit metabolome of tomatoes showed that ZnO NMs upregulated the biosynthesis of unsaturated fatty acids and sphingolipid metabolism and elevated the levels of linoleic and arachidonic acids. The ZnO NMs-treated tomato fruits were then digested in a human gastrointestinal tract model. The results of essential mineral release suggested that the ZnO QDs treatment increased the bioaccessibility of K, Zn, and Cu by 14.8-35.1% relative to the control. Additionally, both types of ZnO NMs had no negative impact on the α-amylase, pepsin, and trypsin activities. The digested fruit metabolome in the intestinal fluid demonstrated that ZnO NMs did not interfere with the normal process of human digestion. Importantly, ZnO NMs treatments increased the glycerophospholipids, carbohydrates, amino acids, and peptides in the intestinal fluids of tomato fruits. This study suggests that nanoscale Zn can be potentially used to increase the nutritional value of vegetable crops and can be an important tool to sustainably increase food quality and security.

QTL mapping and candidate gene analysis of low‐temperature tolerance at the germination stage of soybean

AbstractWhen soybean seeds encounter low temperature during germination, the vigour and germination of soybean seeds are affected, which leads to a lack of seedlings and weak seedlings, resulting in yield reduction. In‐depth analysis of the genetic mechanism of soybean seed germination tolerance to low‐temperature stress and the cultivation of soybean‐tolerant varieties is the key to resisting low‐temperature stress at the germination stage. In the present study, a chromosome segment substitution line (CSSL) population constructed by wild soybean ZYD00006 and cultivated soybean SN14 was used to map three quantitative trait loci (QTLs). Five candidate genes were obtained by gene annotation, GO enrichment analysis and protein function prediction. The candidate genes were subjected to bioinformatics analysis, qRT‐PCR analysis, trypsin activity analysis and soluble protein content analysis. The results showed that the secondary and tertiary structures of the Glyma.09G162700 proteins were mutated. Within 0–72 h, the expression of Glyma.09G162700 in the two materials with different tolerances was consistent, and the change in trypsin activity was consistent with the change in protein expression. Through haplotype analysis, Glyma.09G162700 produced two haplotypes at −2420 bp. The germination rate (GR) and relative germination rate (RGR) of the two haplotypes were significantly different, indicating that the two haplotypes have wide applicability in soybean resources. In summary, Glyma.09G162700 may be a candidate gene for low‐temperature tolerance at the germination stage of soybean. These results provide an important theoretical basis and marker information for analysing the mechanism of low‐temperature tolerance in soybean germination stage and cultivating low‐temperature‐tolerant varieties.

Differential modulation of digestive enzymes and energy reserves at different times after feeding in juveniles of the marine estuarine-dependent flatfish Paralichthys orbignyanus (Valenciennes, 1839).

Integrative studies are lacking on the responses of digestive enzymes and energy reserves in conjunction with morphological traits at distinct postprandial times in marine estuarine-dependent flatfishes of ecological and economic importance, such as Paralichthys orbignyanus. We determined total weight (TW), hepato-somatic index (IH), activities of digestive enzymes in the intestine, and the concentration of energy reserves in the liver and the muscle at 0, 24, 72, and 360 h after feeding in juveniles of P. orbignyanus. Amylase activity decreased at 72 h (about 30%). Maltase, sucrose, and lipase activities reached peak at 24 h (67%, 600%, and 35%, respectively). Trypsin and aminopeptidase-N activities at 24 and 72 h, respectively, were lower than those at t = 0 (53% and 30%). A peak increase in the concentration of glycogen and triglycerides in the liver (24 h) (86% and 89%, respectively) occurred. In muscle, glycogen and triglyceride concentrations were unchanged at 24 h and higher at 72 and 360 h (100% and 60%). No changes were found in TW, IH, free glucose in the liver and muscle, and protein in the liver. The protein concentration in the muscle sharply increased at 24 and 360 h after feeding (60%). The results indicate a distinct and specific response of central components of carbohydrate, lipid, and protein metabolism that could be adjustments at the biochemical level upon periods of irregular feeding and even of long-term food deprivation inside coastal lagoons or estuaries. The distinct responses of digestive enzymes in the intestine and energy reserves in the liver and muscle suggest the differential modulation of tissue-specific anabolic and catabolic pathways that would allow the maintenance of physical conditions.

Dietary calcium requirement of bullfrog (Lithobates catesbeiana)

This study was conducted to determine dietary calcium (Ca) requirement of bullfrog (Lithobates catesbeiana). Six diets were formulated to contain 0.55% (control), 0.96%, 1.30%, 1.72%, 2.02% and 2.53% Ca. Each diet was fed to triplicate tanks of bullfrogs (24.96 ± 0.03 g), and each tanks was stocked with 13 bullfrogs. Bullfrogs were fed twice daily (8:30 and 17:30) to apparent satiation for 8 weeks. Weight gain rate of bullfrogs fed the 1.72% Ca diet was significantly higher than the control group (P < 0.05). The content of Ca was significantly increased in the whole body and vertebrae of bullfrogs fed the 1.72%, 2.02% and 2.53% diets compared to those fed the 0.55%, 0.96% and 1.30% Ca diets (P < 0.05). Furthermore, bullfrogs fed the 1.30%, 1.72% and 2.02% diets had higher activity of trypsin than those fed the 0.55% and 2.53% Ca diets (P < 0.05). Apparent digestibility coefficient of dry matter was higher in bullfrogs fed the 1.72% Ca diet than those fed the 0.55% and 2.53% diets (P < 0.05). Bullfrogs fed the 1.72% Ca diet had higher activity of superoxide dismutase in the serum than those fed the 0.55% and 2.53% diets (P < 0.05). Compared to the control group, contents of 1,25 dihydroxyvitamin D3 and parathyroid hormone in the serum as well as vitamin D receptor and sodium-calcium exchanger genes expression in the kidney were significantly decreased in bullfrogs fed the 1.72%, 2.02% and 2.53% Ca diets (P < 0.05). Compared to the control group, intestinal sodium-calcium exchanger gene expression was significantly decreased in bullfrogs fed the 1.72% and 2.02% Ca diets (P < 0.05). Based on second order polynomial analysis of weight gain rate, dietary Ca requirement of bullfrog was 1.89%.