Intestinal Enzyme Activities Research Articles

Evaluation of stimbiotic on growth performance and intestinal development of broilers fed corn- or wheat-based diets

In the antibiotics-free era, stimbiotic (STB) has been suggested as a new alternative of antibiotic growth promoters to modulate intestinal health via stimulating dietary fiber utilization in poultry production. The aim of this study was to evaluate the effects of STB supplementation in corn- or wheat-basal diet on growth performance, intestinal development, and function of broilers. A total of 512 one-day-old Arbor Acres(AA)broilers were randomly allocated 4 treatments, including corn group (CG), corn+100 g/t STB (CG+STB), wheat group (WG), wheat+100 g/t STB (WG+STB). The broilers were weighed at the days of 14, 28, and 42, of which 8 repetitions per treatment were randomly selected to determine the intestinal morphology, intestinal barrier, and cecal microbiota and metabolites. Our data showed that STB increased (P < 0.05) feed intake, body weight and reduced FCR for the overall period (0-42 d). At 28 d of age, significant increases in villus height and the villus height-to-crypt depth ratio (V/C) were found in the STB supplementation groups (P < 0.05). Addition of STB significantly increased intestinal mucosal DAO and AMPK enzyme activity and the gene expression of OCLN, CLDN1, ZO1, MUC2, SGLT1, PEPT1, FABP2, Ghrelin, and GCG in jejunum (P < 0.05), and significantly decreased the expression of the PYY gene. In addition, STB increased the relative abundance of beneficial bacteria, such as Akkermansia, Bifidobacterium, and Oscillospirales (P < 0.05). A significant increase in cecal short-chain fatty acid (SCFAs) concentration was also observed in the STB supplementation groups. At the cellular level, STB cannot directly increase the expression of small intestinal epithelial cells, and may indirectly improve intestinal barrier function by increasing the level of sodium butyrate. Overall, these results indicated that STB supplementation could improve the growth performance, intestinal development and barrier functions, and fiber fermentation in cecum of broiler chickens.

Dietary inulin benefits on growth, digestive ability and intestinal microbiota in yellow catfish exposed to ammonia

Inulin can be selectively utilized by the host intestinal microbiota to promote growth and stress resistance. Although inulin is rarely reported in aquatic animal, it has been widely used in feed production. This study evaluated the effects of dietary inulin on growth, digestive ability, and intestinal microbiota of yellow catfish exposed to ammonia. The results showed that ammonia stress resulted in growth retardation (weight gain and specific growth rate decreased), which may be related to reduced feed utilization (feed intake and feed conversion ratio increased). Dietary inulin supplementation can improve intestinal digestive enzyme activity (lipase and pepsin), blood health and immune response (total protein, 50 % hemolytic complement, immunoglobulin M increased; total cholesterol, glucose, aspartate aminotransferase, and alanine aminotransferase decreased), and liver antioxidant enzyme activity (superoxide dismutase and catalase), but reduce inflammatory response (interleukin-1 and tumor necrosis factor-α) of yellow catfish under ammonia stress. In addition, inulin can increase Turicibacter abundance, and reduced Achromobacter abundance in intestinal microbiota, which was positive correlation with improved growth of yellow catfish exposed to ammonia. This study suggests that inulin can be used as a potential feed additive to help yellow catfish cope with ammonia stress.

Effects of Dietary Supplementation of Lacticaseibacillus Chiayiensis AACE3 on Hepatic Antioxidant Capacity, Immune Factors and Gut Microbiology in Nandan Yao Chicks.

The growing issue of antibiotic resistance has restrained the utilization of antibiotics as growth enhancers in the poultry industry. Probiotics are candidates for replacing antibiotics in the poultry industry. However, probiotics are strain-specific and their efficacy needs to be investigated before applying them. The aim of this study was to assess the positive effects of Lacticaseibacillus chiayiensis AACE3 on the health and gut microbiota of Nandan Yao chicks. The results showed that compared with the blank control (NC) and aureomycin (PC) groups, L. chiayiensis AACE3 increased final body weight (BW), villus height and improved the ratio of villus height to crypt depth in chicken jejunal tissues. L. chiayiensis AACE3 also increased the activity of hepatic antioxidant enzymes (SOD, CAT and T-AOC) and reduced hepatic oxidative damage (MDA). Furthermore, compared to NC, L. chiayiensis AACE3, the activity of intestinal digestive enzymes (i.e., α-amylase, lipase and trypsin) was increased. L. chiayiensis AACE3 upregulated the production of IgA and IgG and downregulated the production of IL-6, IL-1β and TNF-α in chicken serum. Moreover, supplementation of L. chiayiensis AACE3 enhances the diversity of gut microbes. At the phylum level, the abundance of Actinobacteriota and Proteobacteria decreased with L. chiayiensis AACE3 supplementation, while the abundance of Verrucomicrobiota and Bacteroidetes increased. At the genus level, there was an increase in the abundance of potential probiotics Akkermansia, Romboutsia, Subdoligranulum, and Lactobacillus. This study confirms that L. chiayiensis AACE3 is an excellent feed additive as an alternative to aureomycin and offers various advantages for the healthy growth of chickens during the brooding period by positively affecting their gut microbiome.

Regulation of feed intake, digestive enzyme activity, and growth in response to live feed and prepared diet during early rearing of Labeo rohita

A 35 day feeding trial in a replicate of five was conducted to evaluate the impact of partial and total replacement of live feed (LF) with nanoparticulate-prepared diet (ND) on early rearing of rohu ( Labeo rohita (Hamilton, 1822)). Larvae 3 days after hatching (DAH) were evenly distributed into three groups; T1 was reared exclusively on LF, T2 was on ND, and T3 was co-fed both LF and ND (1:1). All groups showed a feed-dependent increase in growth and the expression of genes involved in feed intake and growth with age DAH. The T3 group showed significantly higher weight gain, specific growth rate, and expression of insulin-like growth factor-1 followed by the T2 group, while the highest expression of ghrelin and growth hormone secretagogue receptor was observed in T3 followed by T1. Furthermore, leptin showed the highest expression in the T2 followed by the T1 group. The intestinal enzymes showed variable trends, with the highest activity of cellulase, amylase, and protease in the T1, T2, and T3 groups, respectively. Moreover, in all groups, cellulase increased continuously with age DAH, while amylase and protease showed a positive correlation up to 30 DAH and then declined. The results of this study could be helpful in larval nutrition programming.

Use of fermented tea residues as a feed additive and effects on growth performance, body composition, intestinal enzyme activities, and inflammatory biomarkers in juvenile largemouth bass (Micropterus salmoides)

This study evaluated the effects of fermented tea residues (TF) on growth capacity, body composition, digestive enzyme activity, intestinal immunity, and inflammatory biomarkers in juvenile largemouth bass (Micropterus salmoides). For the study, four diets were produced: T0 (basal diet), T1, T2 and T3 replaced 2 %, 4 % and 6 % of the basal diet with TF, respectively. All fish were classified into four treatments at random, each of which included 20 fish and three duplicates and reared for 56 days. The results of our trials are as follows: 1) Supplementation with 2 % TF increased the weight gain rate (WGR), final body length (FL) and final body weight (FW) of juvenile largemouth bass (p < 0.05 ). 2) Compared with T0, intestinal protease, lipase and amylase activity increased in juvenile largemouth bass in T2 and T3 groups after supplementation with TF (P < 0.05 ). 3) Feeding TF significantly enhanced the alkaline phosphatase (AKP), superoxide dismutase (SOD), lysozyme (LZM), acid phosphatase (ACP), glutathione peroxidase (GSH-Px) and catalase (CAT) activities and total antioxidant capacity (T-AOC) level in the intestine of juvenile largemouth bass and reduced the malondialdehyde (MDA) content in the intestine compared with T0 (P < 0.05 ). 4) Supplementation with TF enhanced the mRNA expression of intestinal anti-inflammatory factors 1L-10 and TGF-β and reduced the expression of pro-inflammatory factors IL-1β, IL-15, TNF-α and IL-8 in largemouth bass (P < 0.05 ). In conclusion, supplementation with TF could promote growth performance, activity of intestinal digestive enzymes and increase intestinal immunity in juvenile largemouth bass, with a 2 % addition being the most effective.

Effects of triclosan adsorption on intestinal toxicity and resistance gene expression in Xenopus tropicalis with different particle sizes of polystyrene

Microplastics (MPs) are commonly found with hydrophobic contaminants in the water column and pose a serious threat to aquatic organisms. The effects of polystyrene microplastics of different particle sizes on the accumulation of triclosan in the gut of Xenopus tropicalis, its toxic effects, and the transmission of resistance genes were evaluated. The results showed that co-exposure to polystyrene (PS-MPs) adsorbed with triclosan (TCS) caused the accumulation of triclosan in the intestine with the following accumulation capacity: TCS + 5 µm PS group > TCS group > TCS + 20 µm PS group > TCS + 0.1 µm PS group. All experimental groups showed increased intestinal inflammation and antioxidant enzyme activity after 28 days of exposure to PS-MPs and TCS of different particle sizes. The TCS + 20 µm PS group exhibited the highest upregulated expression of pro-inflammatory factors (IL-10, IL-1β). The TCS + 20 µm group showed the highest increase in enzyme activity compared to the control group. PS-MPs and TCS, either alone or together, altered the composition of the intestinal microbial community. In addition, the presence of more antibiotic resistance genes than triclosan resistance genes significantly increased the expression of tetracycline resistance and sulfonamide resistance genes, which may be associated with the development of intestinal inflammation and oxidative stress. This study refines the aquatic ecotoxicity assessment of TCS adsorbed by MPs and provides informative information for the management and control of microplastics and non-antibiotic bacterial inhibitors.

The effects of fermented feedstuff derived from Citri Sarcodactylis Fructus by-products on growth performance, intestinal digestive enzyme activity, nutrient utilization, meat quality, gut microbiota, and metabolites of broiler chicken.

This research aimed to assess the impact of fermented Citri Sarcodactylis Fructus by-products (FCSF) on the growth performance, gut digestive enzyme activity, nutrient utilization efficiency, gut microbiota, and their metabolites in broiler chickens. A total of 1,080 male broiler chickens were allocated into four groups (T1-T4) consisting of 6 replicates per group, each containing 45 chickens. The basal diet was provided to group T1, while groups T2, T3, and T4 were supplemented with 1%, 3%, and 5% FCSF in the basal diet, respectively. The experimental period was 42 days. The findings revealed that supplementing FCSF improved the FW and ADG of broiler chickens, and led to a reduction in the F/G, ADFI, and mortality rate of broiler chickens (p < 0.05). Furthermore, supplementation with 3% and 5% FCSF improved the thigh yield, semi-eviscerated carcass yield, slaughter yield, and lipase activity in the duodenum and ileum of birds (p < 0.05). Additionally, supplementing 3% FCSF enhanced the activity of protease in the duodenum of broilers (p < 0.05). Moreover, supplementing 3% FCSF enhanced the utilization of total phosphorus, dry matter, crude protein, and crude ash in the feed by broilers (p < 0.05). Compared with the control group, supplementation of 3% and 5% FCSF reduced the serine content in broiler chicken breast meat (p < 0.05). Supplementing 1% FCSF significantly increased the C14:0, C14:1, and C20:1 content in the breast meat compared to the other experimental groups (p < 0.05). The levels of C20:4n6 and C23:0 in the breast meat of birds of FCSF supplemented groups were lower than in T1 (p < 0.05). Furthermore, the content of ∑ω-3PUFA decreased after supplementing with 3% and 5% FCSF (p < 0.05). 16SrDNA showed that supplementing 3% FCSF reduced the ACE, Chao1, and Shannon indices in the cecum of birds (p < 0.05). Supplementing 3% FCSF also decreased the abundance of the phylum Desulfobacterota and improved genera Coprobacter and Prevotella in the cecum of broiler chickens (p < 0.05). Metabolomic analysis of the gut microbiota revealed that supplementing 3% FCSF upregulated 6 metabolites and downregulated 16 metabolites (p < 0.05). Moreover, supplementing 3% FCSF downregulated 12 metabolic pathways and upregulated 3 metabolic pathways (p < 0.05). In summary our findings indicate that supplementing FCSF can improve the growth performance of broiler chickens by enhancing intestinal digestive enzyme activity, nutrient utilization, improving gut microbial diversity, and influencing the metabolism of gut microbiota.

Effects of high NaHCO3 alkalinity on growth, tissue structure, digestive enzyme activity, and gut microflora of grass carp juvenile.

With the gradual decrease in freshwater resources, the available space for freshwater aquaculture is diminishing. As a result, saline-alkaline water aquaculture has emerged as a crucial method to fulfill the increasing demand. This study investigates the impact of alkaline water on the growth performance, tissues (gill, liver, and kidney), digestive enzyme activity, and intestinal microbiology in grass carp (Ctenopharyngodon idella). The aquarium conditions were set with sodium bicarbonate (18mmol/L (LAW), 32mmol/L (HAW)) to simulate the alkaline water environment. A freshwater group was the control (FW). The experimental fish were cultured for 60days. The findings revealed that NaHCO3 alkaline stress significantly reduced growth performance, caused alterations in the structural morphology of gill lamellae, liver, and kidney tissues, and led to decreased activity of intestinal trypsin and lipase amylase (P < 0.05). Analysis of 16S rRNA sequences demonstrated that alkalinity influenced the abundance of dominant bacterial phyla and genera. Proteobacteria showed a significant decrease under alkaline conditions, while Firmicutes exhibited a significant increase (P < 0.05). Furthermore, alkalinity conditions significantly reduced the abundance of bacteria involved in protein, amino acid, and carbohydrate metabolism, cell transport, cell decomposition, and environmental information processing. Conversely, the abundance of bacteria associated with lipid metabolism, energy metabolism, organic systems, and disease functional flora increased significantly under alkalinity conditions (P < 0.05). In conclusion, this comprehensive study indicates that alkalinity stress adversely affected the growth performance of juvenile grass carp, likely due to tissue damage, reduced activity of intestinal digestive enzymes, and alterations in intestinal microorganisms.

Особенности пищевых интолерантностей у больных с синдромом раздраженного кишечника

The aim was to evaluate the activity of intestinal carbohydrases in patients with irritable bowel syndrome (IBS) with symptoms of food intolerance. Material and methods. 126 patients with IBS (83 women and 43 men, median age – 32.0 years (Q1–Q3: 27–38 years)) were examined. The diagnosis of IBS was established on the basis of Roman Criteria IV. A questionnaire was conducted for all patients to identify food intolerances, according to the results of which the patients were divided into three groups: the first – patients with isolated intolerance to foods with a high content of FODMAP; the second – patients with isolated intolerance to milk and dairy products; the third – patients with combined intolerance. To determine the activity of intestinal carbohydrates: lactase, sucrose, maltase and glucoamylase, all patients underwent esophagogastroduodenoscopy with biopsy samples from the duodenum. The activity of carbohydrases was determined by the Dahlquist method in the modification of N.I. Belostotsky. The control group consisted of 30 conditionally healthy people (10 men and 20 women, median age – 33.9 years (Q1–Q3: 24–35)), comparable in age and gender with patients with IBS. The activity of intestinal enzymes in this group was within the reference values. Statistical data processing was carried out using the computer program Statistica 8.0. Results. According to the results of the survey, it was found that out of 126 patients with IBS, 52 (41.3%) patients believed that they had food intolerance to certain foods. Isolated intolerance to foods with a high content of FODMAP was noted by 13 (10.3%) patients, 16 (12.7%) patients believed that they had isolated intolerance to milk and dairy products, and 23 (18.3%) patients indicated combined intolerance. In patients with IBS and isolated intolerance to foods high in FODMAP, the median activity of glucoamylase was 120.0 (68.5–209.2) ng/mg of glucose per 1 mg of tissue per minute (ng/mg × min), maltase – 630.5 (480.7–951.0) ng/mg × min, sucrose – 50.0 (32.8–68.8) ng/mg × min, lactase – 10.5 (5.5–40.5) ng/mg × min. Comparing the activity of carbohydrases with the control group revealed the statistically significant difference (p &lt; 0.05) for each enzyme studied.In the group of patients with IBS and isolated intolerance to milk and dairy products, the median activity of all the intestinal enzymes studied was also lower than that in the control group: the activity of glucoamylase was 107.0 (64.0–174.0) ng/mg × min, maltase – 622.0 (481.5–887.0) ng/mg × min, sucrose – 48.0 (35.5-60.0) ng/mg × min, lactase – 8.0 (3.0–22.5) ng/mg × min. Among patients with IBS and the presence of combined intolerance to foods (with a high content of FODMAP and dairy products), the median activity of all enzymes significantly differed from the control group (p &lt; 0.05). The activity of glucoamylase was 107.5 (57.5–194.2) ng/mg × min, maltase – 627.0 (480.7–911.7) ng/mg × min, sucrose - 47.5(34.8–61.5) ng/mg × min, lactase - 9.0 (4.0–28.8) ng/mg × min. Conclusion. Food intolerance was noted in 52 (41.3%) patients with IBS. Among the patients who noted the presence of all the studied food intolerances (isolated or combined intolerance to milk and dairy products, as well as products with a high content of FODMAP), a significant decrease in the activity of intestinal enzymes (glucoamylase, lactase, sucrose and maltase) was found compared with the control (p &lt; 0.05), which may indicate the presence of they have disaccharidase deficiency

Effect of Dietary Incorporation of Yellow Mealworm as a Partial Fishmeal Replacer on Growth, Metabolism, and Intestinal Histomorphology in Juvenile Meagre (Argyrosomus regius).

Efforts have been made to find alternatives to fish meal (FM), as the sustainability of aquaculture depends on it. Insect meal (IM) is a potential candidate to partially replace FM, being more sustainable and economically viable. In this experimental trial, three diets were tested with different yellow mealworm incorporation: a control diet with no IM, a diet with an inclusion of 10% IM (Ins10), and a diet with an incorporation of 20% IM (Ins20). The diets were tested on 10.5 g meagre for 47 days. The results showed that an IM inclusion higher than 10% affected both growth (2.6 vs. 2.2) and FCR (1.5 vs. 1.9) of meagre juveniles. However, this reduction in growth did not result from lower protein retention or changes in muscle fibre area or density. Little differences were observed in the activity of pancreatic and intestinal enzymes except for aminopeptidase total activity which was higher in the control and Ins10 compared to Ins20 (3847 vs. 3540 mU/mg protein), suggesting no limitations in protein synthesis. Also, the alkaline phosphatase intestinal maturation index was higher in the control group compared to the IM groups (437 vs. 296). On the contrary, several differences were also found in the proteolytic activity in the hepatic and muscle tissues of meagre juveniles fed the Ins10 diet. The inclusion of IM had no impact on intestine histomorphology but changes were detected in the enterocytes of fish from control and Ins10 which showed hypervacuolization and nucleus misplacement compared to the Ins20 treatment. Nevertheless, a higher percentage of Vibrionaceae was recorded for meagre fed on the Ins20 diet. Since no signs of inflammation were observed in the distal intestine, this suggests IM incorporation could have had an important impact on intestinal health due to its antimicrobial properties. This is supported by an increase in the haematocrit in the treatments where IM was added (20 to 25%). In conclusion, incorporations of IM at percentages up to 10% do not seem to have a negative impact on meagre performance at this age but can enhance the fish immune system and protection against intestinal inflammation.

Effect of Purslane (Portulaca oleracea L.) on Intestinal Morphology, Digestion Activity and Microbiome of Chinese Pond Turtle (Mauremys reevesii) during Aeromonas hydrophila Infection.

Large-scale mortality due to Aeromonas hydrophila (A. hydrophila) infection has considerably decreased the yield of the Chinese pond turtle (Mauremys reevesii). Purslane is a naturally active substance with a wide range of pharmacological functions, but its antibacterial effect on Chinese pond turtles infected by A. hydrophila infection is still unknown. In this study, we investigated the effect of purslane on intestinal morphology, digestion activity, and microbiome of Chinese pond turtles during A. hydrophila infection. The results showed that purslane promoted epidermal neogenesis of the limbs and increased the survival and feeding rates of Chinese pond turtles during A. hydrophila infection. Histopathological observation and enzyme activity assay indicated that purslane improved the intestinal morphology and digestive enzyme (α-amylase, lipase and pepsin) activities of Chinese pond turtle during A. hydrophila infection. Microbiome analysis revealed that purslane increased the diversity of intestinal microbiota with a significant decrease in the proportion of potentially pathogenic bacteria (such as Citrobacter freundii, Eimeria praecox, and Salmonella enterica) and an increase in the abundance of probiotics (such as uncultured Lactobacillus). In conclusion, our study uncovers that purslane improves intestinal health to protect Chinese pond turtles against A. hydrophila infection.

Carbohydrate sources influence growth and intestinal enzyme activity in thin-lip grey mullet (Liza ramada) fry

This work is designed to examine the influence of using four different dietary carbohydrate sources (rice-bran RB, wheat-bran WB, wheat-flour WF, and yellow-corn YC) on growth, feed utilization, relative gut length, biochemical composition, blood glucose, and intestinal enzyme activity in thin-lip grey mullet (Liza ramada) fry. Five diets were evaluated during a 68 days using fifteen glass aquaria (30×40×100 cm) contained 22 L. ramada (0.3 g/fry) per aquarium which included the marine water. The first set remained in a basal regime (∼25% CP), whereas the other four groups provided the tested carbohydrate source separately. Fry feeding was applied three times per day throughout the whole experimental duration. Findings designated an enhancement in growth and feed utilization for fry nourished on both RB and WF contained diets as compared to the corresponding's for fish fed the YC diet. The weight gain values ranged between 0.98 and 1.28 g/fry for YC and RB respectively. Moreover, a significantly (P ≤ 0.05) higher lipid contents (32.33%) and relative gut length (2.6) of the fry fed the RB diet remained detectable in comparison to other diets. In addition, these results showed significantly variances in concentrations amongst nutritional treatments for highest average blood glucose value (126.33 u/ml), lipase (14 u/ml), and amylase (1982.7 u/ml) in fry fed RB enzymes and liver glycogen (107.3 mg/g) for YC.

Effects of dietary trimetlylamine oxide on the growth performance, feed utilization and appetite regulation of Chinese mitten crab (Eriocheir sinensis)

A 60-day feeding trial was conducted to evaluate the effects of different TMAO (trimetlylamine oxide) supplement levels (0%, 0.12%, 0.24%, and 0.48%, named G1, G2, G3, and G4, respectively) on growth performance, feed utilization, intestinal enzyme activities and appetite regulation of Eriocheir sinensis. The results showed that diet supplemented with 0.24% trimetlylamine oxide (TMAO) significantly improved the weight gain rate (WGR), specific growth rate (SGR), feed intake (FI) and feed utilization (p < 0.05), while having no effect on the survival rate (SR) and molting frequency (MF) of crabs (p > 0.05). Moreover, moderate dietary TMAO levels significantly improved the intestinal enzyme activities (α-amylase, trypsin, lipase and γ-glutamyl transferase) of crabs. The RT-qPCR results showed that the expressions of the orexigenic neural signal-related factors neuropeptide Y (npy) and ghrelin were significantly up-regulated. The expressions of AKT/TOR/4E-BP signaling pathway related genes (protein kinase B (akt), target of rapamycin (tor) and 4E-binding protein (4e-bp)), anorexia-regulating peripheral hormones (leptin and cholecystokinin (cck)) and leptin receptor (lepr) were significantly down-regulated in the hepatopancreas, thoracic ganglia and cranial ganglia tissues. The anorexigenic neural signal-related factors cocaine and amphetamine regulated transcript (cart) and pro-opiomelanocortin (pomc) were significantly down-regulated in the hepatopancreas, thoracic ganglia and cranial ganglia tissues. Based on the quadratic regression analysis of WGR against dietary TMAO level, the optimum TMAO requirement of E. sinensis was suggested to be 0.27%. In conclusion, present results suggested that dietary supplementation with 0.27% TMAO can improve the growth performance, feed intake, intestinal enzyme activities and appetite regulation of E. sinensis.

Effects of Dietary Lysine Level on Growth Performance and Protein Metabolism in Juvenile Leopard Coral Grouper (Plectropomus leopardus).

An 8-week feeding trial was conducted to evaluate the effects of dietary lysine level on growth performance and protein metabolism of juvenile leopard coral grouper (Plectropomus leopardus) and thereby obtained the optimal dietary lysine requirement of P. leopardus. Six isoproteic and isolipidic experimental diets were formulated to contain 1.10%, 1.69%, 2.30%, 3.08%, 3.56%, and 4.36% lysine of diets, respectively. Each diet was assigned at random to triplicate groups of 25 juveniles (initial mean weight is 10.57 g) per tank in a flow-through mariculture system maintained at 27-30°C. Dietary inclusion of 2.30-3.08% lysine improved the weight gain rate (WGR) and specific growth rate and decreased the feed conversion ratio (FCR) of juveniles (P < 0.05). The intestinal digestive enzyme (trypsin, amylase, and lipase) activities were overall enhanced by dietary inclusion of 3.08-3.56% lysine (P < 0.05). The mammalian target of rapamycin (mTOR) signaling pathway was activated in fish fed diets with 1.69-2.30% lysine by upregulating the relative expression levels of hepatic TOR and S6K1 (p70 ribosomal protein S6 kinase 1) but downregulating the relative expression level of hepatic 4E-BP2 (eIF4E-binding protein 2). Conversely, the amino acid response signaling pathway was inhibited in fish fed diet with 2.30% lysine by downregulating the relative expression levels of hepatic GCN2 (general control nondepressible 2), ATF3 (activating transcription factor 3), ATF4a (activating transcription factor 4a), and ATF4b (activating transcription factor 4b). Additionally, dietary 1.69-3.08% lysine enhanced the plasma total protein level and hepatic lysine α-ketoglutarate reductase activity but depressed the blood urea nitrogen level and hepatic adenosine monophosphate deaminase activity (P < 0.05). Moreover, dietary 3.08% lysine increased the contents of whole-body crude protein and total amino acids, while 1.69%-4.36% lysine depressed the whole-body lipid content (P < 0.05). These results indicated that optimal dietary lysine increased the digestive enzyme activities, promoted protein synthesis but depressed protein degradation, and thereby improved the growth performance of P. leopardus. Based on the second-order polynomial model, the optimal lysine requirement of juvenile P. leopardus for WGR, FCR, and lysine deposition was 2.60%-2.97% of diets (4.91%-5.60% of dietary protein).

Effects of different diets on growth performance, digestive enzyme activities and intestinal bacterial community of juvenile Chinese giant salamander (Andrias davidianus)

This study analyzed the growth performance, digestive enzyme activities and intestinal microbial community in HC group (fed with Chironomid larvae), HH group (fed with Chironomid larvae plus Earthworms) and QY group (fed with Earthworms) of juvenile Chinese giant salamander (Andrias davidianus) after farming for 60 days. The results showed that diet can affect the growth performance, digestive enzyme activities and intestinal mcirobiota composition of juvenile Chinese giant salamander. The growth performance in juvenile Chinese giant salamander of HC group was significantly higher than that of HH group and QY group. The ether extract content in muscles of juvenile Chinese giant salamander of HH group and QY group was significantly lower than that of HC group. The intestinal digestive enzyme activities in juvenile Chinese giant salamander of HC group were significantly lower than that of HH group and QY group. The intestinal microbial richness and diversity in juvenile Chinese giant salamander of HH group and QY group were significantly higher than that of HC group. The most dominant phylum of HC group and HH group was Firmicutes but QY group was Bacteroidota, and the most dominant genus of HC group was Clostridium_sensu_stricto_1 but HH group and QY group was Bacteroides. The 24 specific bacterial groups with different classification levels had significant differences in three diet groups of juvenile Chinese giant salamander and these specific bacteria were concentrated in Firmicutes, Proteobacteria and Bacteroidota. Thus, the above studies indicated that Chironomid larvae as diet can increase the growth performance of juvenile Chinese giant salamander, while the addition of Earthworms as diet can enhance digestive ability and change microbiota composition in intestine of juvenile Chinese giant salamander.

Feed nutritional composition affects the intestinal microbiota and digestive enzyme activity of black soldier fly larvae.

Using black soldier fly larvae (BSFLs) to treat food waste is one of the most promising environmental protection technologies. We used high-throughput sequencing to study the effects of different nutritional compositions on the intestinal microbiota and digestive enzymes of BSF. Compared with standard feed (CK), high-protein feed (CAS), high-fat feed (OIL) and high-starch feed (STA) had different effects on the BSF intestinal microbiota. CAS significantly reduced the bacterial and fungal diversity in the BSF intestinal tract. At the genus level, CAS, OIL and STA decreased the Enterococcus abundance compared with CK, CAS increased the Lysinibacillus abundance, and OIL increased the Klebsiella, Acinetobacter and Bacillus abundances. Diutina, Issatchenkia and Candida were the dominant fungal genera in the BSFL gut. The relative abundance of Diutina in the CAS group was the highest, and that of Issatchenkia and Candida in the OIL group increased, while STA decreased the abundance of Diutina and increased that of Issatchenkia. The digestive enzyme activities differed among the four groups. The α-amylase, pepsin and lipase activities in the CK group were the highest, and those in the CAS group were the lowest or the second lowest. Correlation analysis of environmental factors showed a significant correlation between the intestinal microbiota composition and digestive enzyme activity, especially α-amylase activity, which was highly correlated with bacteria and fungi with high relative abundances. Moreover, the mortality rate of the CAS group was the highest, and that of the OIL group was the lowest. In summary, different nutritional compositions significantly affected the community structure of bacteria and fungi in the BSFL intestinal tract, affected digestive enzyme activity, and ultimately affected larval mortality. The high oil diet gave the best results in terms of growth, survival and intestinal microbiota diversity, although the digestive enzymes activities were not the highest.

Effect of Bacillus amyloliquefaciens LSG2-8 on the intestinal barrier function of Amur minnow (Rhynchocypris lagowskii).

Probiotics have been widely used in aquaculture. This article aims to study the effect of Bacillus amyloliquefaciens LSG2-8 on the intestinal barrier function of Rhynchocypris lagowskii. B. amyloliquefaciens LSG2-8 were added to R. lagowskii basal diets (CK) as additives at four concentrations: 1.0 × 106 (D-6), 1.0 × 107 (D-7), 1.0 × 108 (D-8) and 1.0 × 109 (D-9) CFU/g by dry weight of basal diet. After a 56 days feeding experiment, the intestinal digestive enzymes and immune enzymes activity of R. lagowski on group D-6, D-7, D-8 and D-9 diet were significantly higher than the control (P < 0.05). In molecular experiments, we found that the levels of TGF-β mRNA, IL-10 mRNA, ZO-1 mRNA and Claudin-3 mRNA in group D-8 R.. lagowskii were significantly higher (P < 0.05) than the control and other groups. Furthermore, the levels of IL-1β and IL-8 mRNA of R. lagowski on group D-6, D-7, D-8 and D-9 diet were significantly lower than the control (P < 0.05). In addition, we found that B. amyloliquefaciens LSG2-8 can regulate the intestinal flora balance and improve the intestinal structure of R. lagowskii. In conclusion, B. amyloliquefaciens LSG2-8 can improve the intestinal barrier function of R. lagowskii,and can be used as a feed additive in aquaculture.

Corrigendum: Effect of dietary soybean meal on growth performance, apparent digestibility, intestinal digestive enzyme activity and muscle growth-related gene expression of Litopenaeus vannamei

CORRECTION article Front. Mar. Sci., 12 May 2023Sec. Aquatic Physiology Volume 10 - 2023 | https://doi.org/10.3389/fmars.2023.1197207

Effects of cannabidiol on growth performance, appetite, antioxidant capacity and liver inflammatory gene expression of juvenile large yellow croaker (Larmichthys crocea) fed diets with high soybean oil level

This study evaluated the effects of cannabidiol (CBD) on growth performance, appetite, antioxidant capacity and liver inflammatory gene expression in juvenile large yellow croaker (Larmichthys crocea) fed diets with fish oil replaced by soybean oil. Six iso‑nitrogenous and isolipidic diets were formulated with fish oil (FO, the standard diet compared with the control only), soybean oil (SO, the control) and SO supplemented with 25, 50, 100 and 250 mg/kg CBD. After 9-week feeding, with the increase of CBD supplementation in SO diet, the growth performance (final body weight, specific growth rate and feed intake) and the intestinal digestive enzyme activities (amylase, lipase and trypsin) showed a significantly quadratic trend of variation and the maximum were observed in the fish fed SO diets with 100 mg/kg CBD. Correlation analysis showed that 100 mg/kg CBD supplemented in the SO diet could promote appetite of fish by inhibiting the mRNA expression of pro-opiomelanocortin in hypothalamus. The activities of aspartate transaminase and alanine transaminase and total protein level in the serum of fish showed a significantly quadratic trend with the supplementation of CBD increasing in SO diets, and the lower were observed in fish fed SO diets with CBD. Compared with the control, 25, 50, 100 and 250 mg/kg CBD supplemented in SO diets increased peroxidase activity and total antioxidant capacity and decreased malondialdehyde content in the liver of fish, and the highest superoxide dismutase activity was observed in fish fed SO diets with 100 mg/kg CBD. Moreover, fish fed SO diets with 100 and 250 mg/kg CBD had lower mRNA expression of tumor necrosis factor α, interleukin-1β, interleukin-6 and cyclooxygenase-2 in liver of fish compared with the control. In conclusion, 100 mg/kg CBD supplemented in diets with high SO level improved the growth performance and appetite in large yellow croaker. Simultaneously, the supplementation of 100 and 250 mg/kg CBD could promote antioxidant capacity and inhibit the inflammatory gene expression in liver of large yellow croaker fed diets with the high SO level. The optimal supplementation of CBD in diets with high SO level is recommended at 100 mg/kg for large yellow croaker.

Dietary hydrolyzable tannins reduce growth performance and induce histological damage of Chinese seabass (Lateolabrax maculatus)

Chinese seabass (Lateolabrax maculatus) is a popular carnivorous fish with delicious taste. Although the feed value of condensed tannins has been well documented for L. maculatus, information about the effects of hydrolyzable tannins (HTs) on the growth and health of L. maculatus is limited. This study was conducted to assess the effects of dietary HTs on growth performance, body composition, intestinal digestive enzyme activities, serum metabolites, antioxidant and immune response, and intestine and liver morphology of L. maculatus. A total of 640 fish were randomly divided into four groups with four replicates per group and 40 fish per replicate. Four diets were prepared to contain 0 (G0), 1 (G1), 2 (G2), and 4 (G4) g/kg of HTs. Fish were fed to apparent satiation twice a day during the 56-day feeding trial. Results showed that the final body weight, weight gain rate, specific growth rate, and feed intake were linearly decreased (p&amp;lt; 0.001) as dietary HTs increased. All fish had similar (p &amp;gt; 0.05) whole body compositions. Fish fed G2 and G4 had lower (p&amp;lt; 0.05) intestinal trypsin and lipase activities than those fed G0 and G1, whereas G4 had higher (p&amp;lt; 0.05) aspartate aminotransferase and alanine aminotransferase activities than G0. Serum total antioxidant capacity and lysozyme were linearly decreased (p&amp;lt; 0.01), but the malondialdehyde concentration was linearly increased (p&amp;lt; 0.01) as dietary HTs increased. Intestinal villi in G2 and G4 showed increased deformation, and the vacuolation of liver cells began to appear in G1 and was aggravated as dietary HTs increased. This study showed that HTs should be used with caution due to their growth-inhibiting effect, and the dietary HT level for L. maculatus is recommended to be less than 1 g/kg.