Intestinal Digestive Enzyme Activities Research Articles

219 Effects of maternal nutrient restriction and rumen-protected arginine supplementation on post-ruminal digestive enzyme activities of lamb offspring

Abstract To determine the effects of maternal nutrient restriction and rumen-protected arginine supplementation on post-ruminal digestive enzymes in lambs, 31 multiparous, Rambouillet ewes were allocated to one of three dietary treatments at 54 d of gestation. Dietary treatments were 100% of nutrient requirements (control, CON; n=11), 60% of control (restricted, RES; n=10), or RES plus a rumen-protected arginine supplement dosed at 180 mg/kg BW once daily (RES-ARG; n=10). At parturition, lambs were immediately removed from dams and reared independently. Milk-replacer and alfalfa hay + creep feed was offered for ad libitum intake. At day 54 of age, lambs were slaughtered and the pancreas and small intestine were collected. Pancreatic (α-amylase, trypsin) and small intestinal (maltase, glucoamylase, sucrase, isomaltase, lactase) digestive enzyme activities were assayed. Data were analyzed using the GLM procedure of SAS with treatment and fetal sex included in the model statement. Contrast statements were used to determine differences between means for effects of restriction (CON vs. RES and RES-ARG) and rumen-protected arginine supplementation (RES vs. RES-ARG). There was no influence (P≥0.32) of maternal nutrient restriction or rumen-protected arginine supplementation on pancreatic or small intestinal protein concentrations. No treatment effects were observed (P≥0.14) for enzymes involved in starch digestion including pancreatic α-amylase and small intestinal maltase, glucoamylase, and isomaltase. Sucrase activity was undetected in the small intestine of lambs across all treatments. Maternal nutrient restriction tended to increase (P=0.09) pancreatic trypsin specific activity in lambs. Lactase specific activity in the small intestine of lambs tended to decrease (P=0.08) with maternal nutrient restriction. Rumen-protected arginine supplementation to gestating ewes did not influence (P≥0.19) digestive enzyme activities of lamb offspring. These data suggest that maternal nutrient restriction may result in increased pancreatic trypsin activity of lambs to potentially compensate for inadequate pre-natal nutrient supply.

PSIX-7 Grazing toxic endophyte-infected tall fescue does not influence pancreatic or small intestinal digestive enzyme activities in beef steers

Abstract The objective of this experiment was to determine the influence of toxic endophyte-infected tall fescue exposure on pancreatic and small intestinal digestive enzyme activities in steers. Twelve fescue-naive beef steers [693 ± 42.7 kg of body weight (BW)] were stratified by BW and randomly assigned within BW ranks to graze non-toxic endophyte-infected tall fescue (NTE, n = 6; 0.01 ± 0.009 mg ergovaline + ergovalinine/kg) or toxic endophyte-infected tall fescue (TE, n = 6; 0.50 ± 0.048 mg ergovaline + ergovalinine/kg) pastures for 84 d. After the grazing period, steers were weighed and then slaughtered in three groups for tissue collection. A 1-m segment of the small intestine was collected 5-m distal to the pyloric sphincter. Subsamples of the small intestinal mucosa and pancreas were collected, homogenized in saline, and assayed for protein concentration. Pancreatic and small intestinal digestive enzyme activities were assayed. Data were analyzed using the GLM procedure of SAS as a randomized complete block design for effects of treatment and slaughter group (blocking factor). Steers grazing NTE pastures had a greater (P < 0.001) average daily gain (0.282 vs -0.631 kg/d) and final BW at slaughter (739 vs 620 kg) than steers grazing TE pastures. Small intestinal segment mass and mucosal density (P ≥ 0.16) were not influenced by treatment. Grazing TE pasture did not influence (P ≥ 0.21) pancreatic or small intestinal protein concentrations. Pancreatic α-amylase and trypsin activity per gram pancreas (P ≥ 0.21) or per gram pancreatic protein (P ≥ 0.30) were not influenced by fescue treatment. Small intestinal glucoamylase, isomaltase, and maltase activities did not differ between steers grazing NTE or TE pastures when expressed per gram of intestinal tissue (P ≥ 0.47) or per gram of intestinal protein (P ≥ 0.60). These data indicate that decreased gains observed in cattle consuming TE are not a result of decreased pancreatic or small intestinal digestive enzyme activities.

Fatty Acid Composition and Digestive Enzyme Activities of Rainbow Trout in Response to Dietary Docosahexaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA) During Salinity Acclimation

This physiological study aimed to evaluate the effects of dietary docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on the fatty acid composition and digestive enzyme activities of rainbow trout (Oncorhynchus mykiss) during salinity acclimation. Rainbow trout with an average initial weight of 90.61 g ±9.25 g were fed diets with the quantities of DHA and EPA equaling to 0.54%, 0.95%, 1.40% and 1.79% (abbreviated as DE-0.54, DE-0.95, DE-1.40, and DE-1.79, respectively) for eight weeks, after which the gastric and intestinal fatty acids composition were analyzed. Subsequently, the fish underwent salinity acclimation. On days 1, 4, 7, and 14 after the freshwater was replaced by seawater and at the end of the 8-week period, gastric and intestinal digestive enzyme activities were determined. The results showed that the gastric and intestinal DHA and EPA contents of the fish were positively correlated to their dietary DHA and EPA levels. Low dietary DHA and EPA levels inhibited the protease activity of rainbow trout. Fish in the DE-0.54 group increased the lipase activity to enhance the utilization of lipids maybe due to the inadequate essential fatty acids for fish in this group. Hence, rainbow trout in the DE-0.54 group failed to maintain suitable activities of digestive enzymes after salinity acclimation. Therefore, a diet with minimum 0.95% DHA and EPA levels is necessary for rainbow trout during salinity acclimation.

Partial fishmeal protein replacement with peptides from swine blood modulates the nutritional status, immune response, and intestinal microbiota of hybrid groupers (female Epinephelus fuscoguttatus× male E. lanceolatus)

This study investigated the effects of replacing fish meal (FM) protein with peptides from swine blood (PSB) on the growth, digestion, and absorption capacity of hybrid groupers (female Epinephelus fuscoguttatus × male Epinephelus lanceolatus). It also analyzed their inflammatory-related gene expression, and intestinal microbiota. Four isonitrogenous and isolipidic experimental feeds were formulated to replace 0% (FM), 25% (PSB25), 50% (PSB50), and 75% (PSB75) of the FM protein with PSB. Each experimental diet was fed to triplicate groups of 30 hybrid grouper juveniles for 8 weeks. No significant differences in the weight gain and specific growth rates were found among the FM, PSB25, and PSB50 groups. The intestinal digestive enzyme (lipase, amylase, trypsin, and pepsin) and brush border enzyme (Na+/K+-ATPase, creatine kinase, and γ-glutamyl transpeptidase) activities showed no significant differences among the FM, PSB25, and PSB50 groups. Meanwhile, trypsin, pepsin. Creatine kinase, and γ-glutamyl transpeptidase activities in the PSB group were significantly higher than those of the FM group. No significant differences in the expression levels of the toll-like receptor 21 (TLR21), myeloid differentiation factor 88 (MyD88), and inflammatory cytokines (TNF-α, IL-2, IL-8, and IL-10) were observed among the four groups. The intestinal microbiota results showed no significant differences in alpha diversity among the four groups. At the genus level, at the genus level, Lactobacillus relative abundance was significantly reduced in the PSB10 group compared to that in the FM group. However, no significant differences were found among the FM, PSB50, and PSB75 groups. However, no significant differences were found among the FM, PSB50, and PSB75 groups. These results demonstrated that up to 50% of the FM protein in the feed can be replaced by PSB without adversely affecting the nutritional status and inflammatory response in hybrid groupers. Replacing FM with PSB significantly influences the microbial profile but not the diversity

Effects of Probiotics BaSC06 on Intestinal Digestion and Absorption, Antioxidant Capacity, Microbiota Composition, and Macrophage Polarization in Pigs for Fattening.

This study aimed to compare the effects of BaSC06 and antibiotics on growth, digestive functions, antioxidant capacity, macrophage polarization, and intestinal microbiota of pigs for fattening. A total of 117 pigs for fattening with similar weight and genetic basis were divided into 3 groups: Anti group (containing 40 g/t Kitasamycin in the diet), Anti+Ba group (containing 20 g/t Kitasamycin and 0.5 × 108 CFU/kg BaSC06 in the diet) and Ba group (containing 1 × 108 cfu/Kg BaSC06 in the diet without any antibiotics). Each treatment was performed in three replicates with 13 pigs per replicate. Results showed that BaSC06 replacement significantly improved the ADG (P < 0.05), intestinal digestion and absorption function by increasing the activity of intestinal digestive enzymes and the expression of glucose transporters SGLT1 (P < 0.05) and small peptide transporters PEPT1 (P < 0.05). Besides, BaSC06 supplementation enhanced intestinal and body antioxidant capacity by activating the Nrf2/Keap1 antioxidant signaling pathway due to the increased expression of p-Nrf2 (P < 0.05). Notably, BaSC06 alleviated intestinal inflammation by inhibiting the production of pro-inflammatory cytokines, IL-8, IL-6, and MCP1 (P < 0.05), and simultaneously increasing the expression of M1 macrophage marker protein iNOS (P < 0.05) and M2 macrophage marker protein Arg (P < 0.05) in the intestinal mucosa. Moreover, BaSC06 promoted the polarization of macrophages to M2 phenotype by stimulating the STAT3 signaling pathway. It was also noted that BaSC06 improved microbiota composition by enhancing the proportion of Firmicutes, and reducing that of Bacteroidetes and Proteobacteria. Taken together, our results indicate that dietary supplementation of BaSC06 in pigs for fattening improves the growth, mucosal structure, antioxidative capacity, immune functions (including increasing M1 and M2 polarization of macrophage) and composition of intestinal microbiota, which is much better than antibiotics, suggesting that it is an effective alternative to antibiotics in the preparation of pig feed.

The Impact of Wheat Bran on the Morphology and Physiology of the Gastrointestinal Tract in Broiler Chickens

Simple SummaryRecently, dietary fiber has gained special attention due to its various beneficial effects on poultry. In poultry, moderate amounts of insoluble dietary fiber have been shown to be beneficial to nutrient utilization by improving the physiology of the gastrointestinal tract. Therefore, this study used wheat bran as a source of insoluble fiber to investigate wheat bran on digestive function in broiler chickens. The results indicate that supplementation of 30 g/kg wheat bran enhanced nutrient digestibility by improving antioxidant status, gizzard development, intestinal digestive enzyme activities and morphology in broilers. In conclusion, wheat bran could be used for improving feed efficiency in broilers.There is increasing evidence showing that moderate amounts of insoluble dietary fiber can improve nutrient utilization by positively influencing the physiology of the gastrointestinal tract. The present study was conducted to investigate the effects of wheat bran as a source of insoluble fiber on nutrient digestibility, serum antioxidant status, gastrointestinal development, digestive enzyme activities and intestinal morphology in broiler chickens. A total of 96 one-day-old male Arbor Acre broiler chickens were assigned to two treatments with six replicate cages per treatment and eight birds per replicate for 42 d. Dietary treatments consisted of the control group (CON, control diet) and wheat bran group (WB, 30 g/kg wheat bran). Inclusion of WB increased (p < 0.05) the digestibility of dry matter, organic matter, gross energy and crude protein on Day 42. Birds fed WB had lower (p < 0.05) serum total cholesterol concentration on Day 21, and lower (p < 0.05) serum concentrations of low-density lipoprotein, total cholesterol and total triglyceride on Day 42. Inclusion of WB increased (p < 0.05) serum glutathione peroxidase activity on Day 21 and superoxide dismutase activity on Day 42, but tended (p = 0.07) to decrease serum malondialdehyde concentration on Day 21, and significantly decreased (p < 0.05) serum malondialdehyde concentration on Day 42. Birds fed WB had a greater (p < 0.05) relative weight of gizzard on both Day 21 and 42. Inclusion of WB increased (p < 0.05) activities of amylase and trypsin in pancreas and jejunal mucosa on Day 21, and increased (p < 0.05) amylase activity in pancreas and jejunal mucosa. Birds fed WB had greater (p < 0.05) villus height and villus height to crypt depth ratio in jejunum and ileum on Day 42. In conclusion, supplementation of 30 g/kg WB enhanced nutrient digestibility by improving antioxidant status, gizzard development, intestinal digestive enzyme activities and morphology of broilers.

Effects of substrate on the physiological characteristics and intestinal microbiota of Echiura worm (Urechis unicinctus) juveniles

The effects of environmental factors on the physiological characteristics of Echiura worm Urechis unicinctus have been widely studied, however, the influences of substrate on this species are still unclear. Differences in the growth performance, physiological response, and intestinal microbiota of U. unicinctus juveniles between the sandy and muddy substrates were evaluated in the present study. The results indicated that the weight gain was significantly higher in U. unicinctus juveniles with the sand bottom compared to the mud group, while the survival rate was obviously lower. The activities of intestinal digestive enzymes and the contents of triglyceride, glucose, and total cholesterol in the coelomic fluids had a significant increase in the individuals with the sandy bottom compared to the mud group. The oxidative stress and intestinal inflammatory were induced by the sandy bottom, meanwhile, the antioxidant system and goblet cells were activated to protect the U. unicinctus juveniles. Focused on the intestinal microbiota of U. unicinctus juveniles, Sphingomonadales, Burkholderiales, and Pesudomonadales were more abundant in the mud group. In contrast, Alteromonadales and Rhodobacterales were enriched in the sand group. Moreover, various correlations were observed between the intestinal bacteria and physiological indices, such as Acinetobacter with the lipoprotein- and hepatic-lipase activities, Shewanella with the superoxide dismutase activities, and Cupriavidus with the malondialdehyde contents.

Regulation of growth, intestinal microflora composition and expression of immune-related genes by dietary supplementation of Streptococcus faecalis in blunt snout bream (Megalobrama amblycephala)

A 10-week feeding trial was performed to investigate the effects of Streptococcus faecalis on the growth, intestinal microflora composition and expression of immune-related genes of blunt snout bream (Megalobrama amblycephala). Fish (46.32 ± 0.09 g) were fed four experimental diets containing 0 cfu/g (SF0, control), 1 × 105 cfu/g (SF1), 1 × 106 cfu/g (SF2) and 1 × 107 cfu/g (SF3) of S. faecalis, respectively. Results showed that daily growth index (DGI), feed efficiency ratio (FER), plasma glucose level, plasma contents of total protein and albumin as well as intestinal serous layer (SL), muscular layer (ML), submucous layer (SML), villi thickness (VT) and lamina propria (LP) were all no significant difference among all the treatments, whereas their (except plasma albumin content and intestinal ML) relatively high values were found in the SF2 group. Meanwhile, the intake of the SF2 diets significantly increased plasma globulin content and intestinal digestive enzymes activities, the opposite was true for the activities of plasma aspartate aminotransferase (AST) and alanine transaminase (ALT). In addition, the analysis of the intestinal microbiota showed that fish fed the SF2 diet have the highest values of intestinal alpha diversity and intestinal abundances of Actinobacteria, Chlamydiae, Firmicutes, Planctomycetes, Verrucomicrobia, Clostridium and Synechococcus, while the opposite was true for intestinal abundances of Acinetobacter, Anoxybacillus, Flavobacterium, Planctomyces, Plesiomonas, Pseudomonas, Staphylococcus and Clostridium perfringens. At the molecular level, the expression levels of tumour necrosis factor α (TNF α), interleukin 1β (IL 1β) and heat shock proteins 7 (HSP 70) in head kidney and spleen were all decreased significantly with the increasing S. faecalis levels up to 1 × 106 cfu/g, and then they were increased with further increasing S. faecalis levels. Overall, dietary supplementation of S. faecalis at 1 × 106 cfu/g could improve the intestinal health and innate immunity of blunt snout bream.

Dietary protein and lipid levels affect the growth performance, intestinal digestive enzyme activities and related genes expression of juvenile small yellow croaker (Larimichthys polyactis)

The effects of different dietary protein and lipid levels on juvenile small yellow croaker (Larimichthys polyactis) was experimentally evaluated in 51 days study. Fish (initial weight 16.02±0.50 g) were fed with nine diets contained three levels of protein (430, 470, or 510 g kg−1) and three levels of lipids (60, 90, or 120 g kg−1) in triplicates. Specific growth rate (SGR) and weight gain (WG) of fish on 470 g kg−1 protein and 120 g kg−1 lipid diet were the highest. Protein efficiency ratio (PER) of fish on 120 g kg−1 lipid diet was significantly higher than that of fish on other diets. Intestine lipase activity significantly increased as dietary lipid levels increased, whereas intestine protease activity showed the opposite trend. Relative expression of insulin-like growth factor-1 (IGF-1) and growth hormone receptor (GHR) significantly increased as dietary lipid levels increased. Relative expression of hepatic lipoprotein lipase (LPL) and fatty acid synthase (FAS) were enhanced considerably and decreased by dietary lipid, respectively. In conclusion, a diet containing 470 g kg−1 protein with 120 g kg−1 lipid (protein/energy (P/E) ratio of 24.55 mg protein kJ−1) was found to be optimum for juvenile L. polyactis, which could be a foundation for its nutrition research and large-scale cultivation.

Clostridium butyricum relieves diarrhea by enhancing digestive function, maintaining intestinal barrier integrity, and relieving intestinal inflammation in weaned piglets

The current study aimed to determine how Clostridium butyricum (C. butyricum) relieved diarrhea by evaluating its effects on intestinal digestive enzyme activity, barrier integrity, inflammatory responses, and oxidative stress in weaned piglets. A total of 360 weaned piglets that were 25 days old (180 males and 180 females) were randomly assigned to 5 groups in 6 pens, with 12 pigs per pen, and offered the same antibiotic-free corn-soybean-type basal diet for 30 d. The groups were as follows: no additives (control), basal diet + 250 mg/kg C. butyricum (CB1), basal diet + 500 mg/kg C. butyricum (CB2), basal diet + 1,000 mg/kg C. butyricum (CB3), and basal diet + 2,000 mg/kg C. butyricum (CB4). The incidence of diarrhea decreased quadratically as the amount of C. butyricum supplementation was increased, and this decrease was minimized in the CB2 group. Compared with those in the control group, the duodenal amylase and lipase activities were increased quadratically and maximized in the CB2 group, and the jejunal lipase activity was increased cubically in the CB1 group, while the pancreatic trypsin activity was increased linearly and maximized in the CB4 group. The serum concentration of D-lactic acid responded to the increases in the levels of C. butyricum in a quadratic manner; the minimum level was observed in the CB2 group. Jejunal zonula occludens-1 expression displayed linear and quadratic trends following C. butyricum supplementation, with the maximum response observed in the CB3 group. Quadratic and cubic increases were observed in jejunal alkaline phosphatase activity in the CB3 group. The jejunal IL-10 concentration increased, while the jejunal vascular endothelial growth factor concentration decreased quadratically in response to dietary C. butyricum supplementation in the CB2 group. No significant differences among the groups were observed in terms of the jejunal mucosal concentrations of oxidation-associated enzymes and products. In conclusion, dietary supplementation with appropriate doses of C. butyricum could relieve diarrhea in weaned piglets by enhancing digestive enzyme activity, maintaining intestinal barrier integrity, and relieving intestinal inflammation.

Yeast hydrolysate helping the complex plant proteins to improve the growth performance and feed utilization of Litopenaeus vannamei

Six iso-nitrogenous and iso-lipid experimental diets were formulated to evaluate growth performance, intestinal digestive enzyme activity and the transcript expression of nutrition utilization related genes of the pacific white prawn, Litopenaeus vannamei (initial average body weight: 0.45 ± 0.01 g). The positive control group (LP) contains the 250.0 g/kg fish meal (FM) and 0 g/kg yeast hydrolysate (YH), negative control group (HP) contains the 150.0 g/kg FM and 0 g/kg YH. The 25, 50, 75, and 100 g/kg FM were replaced by plant proteins in the PY1, PY2, PY3 and PY4 groups, respectively, and 30 g/kg YH was supplemented. At the end of the 56-day feeding trial, there were no significantly difference in weight gain rate and specific growth rate between LP and PY1 (P > 0.05). The protein efficiency rate in PY1 was significantly lower than that in LP (P < 0.05). The glucose, total triacylglycerol and total cholesterol concentrations in HP were significantly higher than those in LP, PY1 and PY3 (P < 0.05). The trypsin, amylase and lipase activities in PY1 were significantly higher than those in LP (P < 0.05). In the intestine, the expression levels of fatty acid-binding protein (FABP) and pyruvate kinase (PK) in PY1 were significantly higher than those in LP, PY2, PY3 and PY4 (P < 0.05). In the hepatopancreas, the expression levels of FABP and PK in PY4 were significantly higher than those in HP (P < 0.05). These results revealed that a diet of the 25 g/kg FM were replaced by complex plant proteins, and 30 g/kg YH was fed, had no negative effects on the growth of L. vannamei, and enhanced digestive enzyme activity and transcript expression of metabolic-related genes, improved the ability to utilize carbohydrates and lipids.

Study on the adaptability of common carp (Cyprinus carpio) to diets from the perspective of digestion and absorption

As an ecologically sustainable aquaculture mode, the rice-fish approach has been paid more attention in recent years. In rice paddies, there are plant and animal diet items available to fish, but it is not clear how common carp adapt to different diets. In view of this, common carp (initial weight 492.6 ± 30 g, n = 270) were randomly divided into three groups and fed with earthworms (group A), earthworms + duckweed (group M) and duckweed (group P) respectively. After 8 weeks under these feeding regimes, the intestinal digestive enzymes activities were assayed, and intestinal tissue sections stained with HE and AB-PAS were used to observe the morphology. The results showed that the activities of trypsin and lipase were highest in group A, followed by group M and group P. Group A had greater intestinal fold height, fold width and fold absorption area than the other groups (p < .05), especially in the foregut. Meanwhile, the total number of mucous cells was largest in group P, followed by the groups M and A. Totally, activities and distributions of digestive enzymes, fold height, fold width, fold absorption area and number and distribution of mucous cells of common carp were affected by the type of diet. Based on these results, it was found that common carp has strong adaptability to diets, and it was speculated that the majority of digestion and absorption of protein was concentrated in the foregut, while for starch and cellulose, it was spread out along the whole intestine.

Effects of dietary sodium acetate on food intake, weight gain, intestinal digestive enzyme activities, energy metabolism and gut microbiota in cultured fish: Zebrafish as a model

Acetate is the most abundant short-chain fatty acids (SCFAs) in the gastrointestinal tract of fish. The aim of this study was to investigate the effects of dietary sodium acetate (NaAc) on food intake, weight gain, intestinal digestive enzyme activities, energy metabolism and gut microbiota of zebrafish (Danio rerio). In this study, 1-month-old zebrafish were fed with 0.15% NaAc diet for 4 weeks under satiation feeding. At the end of feeding trial, the level of intestinal acetate in the fish fed with 0.15% NaAc containing diet were significantly increased (p < .05), which was accompanied by a higher weight gain and daily feeding rate compared with the control group (p < .05). Dietary supplementation of 0.15% NaAc significantly promoted the body fat mass, energy gain and energy conversion efficiency, as well as intestinal digestive enzyme (amylase) activity in fish (p < .05). The expression of food intake-related genes (ghre, npy and npy7R) in the brain of fish fed on the diet contacting 0.15% NaAc was higher than that of the control group. Consistently, intracerebroventricular injection of NaAc in the brain of zebrafish also increased the expression of genes related to food intake. The effects of NaAc on orexigenic genes expression in the brain of zebrafish could be prevented by co-injection of atropine, suggesting that acetate played a direct role in controlling appetite through the parasympathetic nerve system. Moreover, there was significantly decrease (p < .05) in the relative abundance of Plesiomonas genus in the fish gut fed on the diet supplemented with NaAc. These data suggest that NaAc has a potential value as fish feed additive in aquaculture.

Dietary Supplementation with Phytase and Protease Improves Growth Performance, Serum Metabolism Status, and Intestinal Digestive Enzyme Activities in Meat Ducks.

Two experiments were conducted to investigate the effects of dietary supplementation with protease and phytase on growth performance, serum physiochemical parameters, and activities of digestive enzymes in jejunal digesta of meat ducks. Experiment 1 was carried out to determine the effects of different protease or phytase on growth performance, serum physiochemical parameter, and activities of digestive enzymes in jejunal digesta of meat ducks to select the optimal phytase or protease. According to the hatching age and initial weight, a total of 5040 Cherry Valley ducks (15 days of age) were randomly assigned into six treatments. Treatments included a basal control diet (CON) and 5 basal diets supplemented with different enzyme preparations, which were phytase preparation A (PA, 160 g/t), phytase preparation B (PB, 800 g/t), protease preparation A (PTA, 80 g/t), protease preparation B (PTB, 300 g/t) and protease preparation C (PTC, 200 g/t). The enzyme activities were as follows: Phytase A and B as well as protease A, B, and C were 50,000, 10,000, 250,000, 50,000, and 60,000 U/g, respectively. Each treatment had 7 replicates with 120 meat ducks per replicate. Experiment 1 lasted for 28 days. The results showed that: compared with the CON group, the PA group significantly decreased contents of serum phosphorus and calcium (p < 0.05), and the PTA, PTB, and PTC groups had higher activities of trypsin in jejunal digesta (p < 0.05), and the activity of jejunal chymotrypsin in PTA group was greater (p < 0.05). Experiment 2 was carried out to determine the effects of dietary supplementation with protease and phytase in low-energy and low-protein diet on growth performance, serum physiochemical parameters, and activities of digestive enzymes in jejunal digesta of meat ducks. According to the hatching age and initial weight, a total of 5760 Cherry Valley ducks (15 days of age) were randomly assigned into four treatments on the basis of a trial of 2 × 2 factorial design. Treatments included a basal control diet (PC), basal diet supplemented with enzymes (PCE), low-energy and low-protein diet (LEP), and low-energy and low-protein diet supplemented with enzymes (LEPE), the nutrient levels of energy and CP of basal diet were 2747.2 cal·ME/kg and 16.80%, respectively, and the nutrient levels of energy and CP of low-energy and low-protein diet decreased 45.90 kcal·ME/kg and 0.52% on the basis of basal diet, respectively. According to the results of experiment 1, phytase A and protease A were determined as the optimal enzyme combination of Experiment 2, and additional dosage of which were identical with Experiment 1. Each treatment had 6 replicates with 240 meat ducks per replicate. Experiment 2 lasted for 28 days. The results showed that: compared with PC and LEP groups, PCE and LEPE groups had higher final weight and average daily gain (ADG) (p < 0.05), higher activities of trypsin and chymotrypsin in jejunal digesta (p < 0.05), lower contents of serum calcium and phosphorus as well as higher levels of high-density lipoprotein in the serum (p < 0.05). In conclusion, dietary supplementation with phytase and protease in different energy and protein diets could increase digestive enzymes in jejunal digesta, effect serum physiochemical parameters, improve metabolic status, and increase the growth performance of meat ducks. Meanwhile, with the dietary supplementation with phytase and protease in the lower energy and protein diet, the growth performance could reach to the degree of the higher energy and increased protein diet, but without the addition of phytase and protease.

Yeast culture promotes the production of aged laying hens by improving intestinal digestive enzyme activities and the intestinal health status

Yeast culture (YC) positively affects the performance of laying hens. The purpose of the present study was to explore the underlying mechanism for the YC-mediated performance improvement. Sixty 67-week-old Hy-Line Brown laying hens were randomly allocated into 2 experimental groups with 5 replicates of 6 birds each. One group was fed a control diet, whereas the other received the control diet supplemented with YC at 3.0 g/kg; treatment lasted for 8 wk. The results showed that dietary YC supplementation increased (P < 0.05) the total egg weight (11.2–13.6%) and egg-laying rate (13.0–13.5%) but decreased (P < 0.05) the feed/egg ratio by 9.3 to 11.0% during weeks 5 to 6 and 7 to 8 compared with the control. However, egg quality, including eggshell strength, eggshell thickness, egg weight, albumen height, egg yolk color, and Haugh unit, was not affected (P > 0.05) by YC supplementation. Furthermore, dietary YC supplementation increased (P < 0.05) chymotrypsin and ɑ-amylase activities by 54.8 to 62.5% in the duodenal chyme and reduced (P < 0.05) plasma endotoxin by 44.1%. YC dietary supplementation also upregulated (P < 0.05) the mRNA levels of intestinal barrier–related genes (occludin and claudin 1) and antimicrobial peptides genes (β-defensin 1 and 7 and cathelicidin 1 and 3) in the duodenum or jejunum compared with the control. In conclusion, dietary YC supplementation improved the performance of aged laying hens, potentially through the upregulation of intestinal digestive enzyme activities and intestinal health-related gene expression.

Sodium butyrate supplementation in high-soybean meal diets for juvenile rice field eel (Monopterus albus): Effects on growth, immune response and intestinal health

An eight weeks feeding trial was conducted to assess the effects of dietary sodium butyrate (NaB) supplementation in diets with graded levels of soybean meal (SBM) on growth performance, antioxidant status, immune response, intestinal digestive enzymes activities and morphology of rice field eel Monopterus albus (initial body weight 14.87 ± 0.11 g). Using the 2 × 4 experimental design, eight isonitrogenous (42% crude protein) and isolipidic (5.5% crude lipid) experimental diets were formulated to contain two SBM levels (18% and 33%, designed as SBM18 and SBM33) and four levels of NaB (0, 250, 500, 1000 mg kg−1 dry diet). The results showed that NaB supplementation significantly increased weight gain (WG), serum superoxide dismutase (SOD) activity and significantly decreased malondialdehyde (MDA) content of fish fed diets with 33% SBM (P < .05). While no significant effects were noticed in SBM18 group (P > .05). At each NaB level, WG of fish fed with 33% soybean meal diet was significantly lower than that of 18% soybean meal except for at 500 mg kg−1 level. Not NaB level but SBM level significantly influenced the feed intake (FI) (P < .05). With the increasing SBM levels, FI significantly decreased at all the NaB supplementation levels (P < .05). At each soybean level, the serum lysozyme (LSZ) activity in fish fed NaB supplement diets was significantly higher compared to the non-supplement diets. Intestinal mucosal morphology was damaged in the SBM33 group without NaB, in contrast to a normal appearance found in fish fed the NaB supplement diets in the SBM33 group. Dietary NaB significantly increased the value of villus height/crypt depth and the intestinal trypsin activity in SBM33 group. At each soybean meal level, lymphocyte number and intestinal creatine kinase (CK) activity significantly increased with the increasing NaB supplementation level. Dietary NaB significantly up-regulated the expression abundance of proliferating cell nuclear antigen (pcda), ornithine decarboxylase (odc), sucrase-isomaltase (si), tight junction protein ZO-1 (zo-1) and alkaline phosphatase (alp), the markers of epithelial proliferation and differentiation. These results suggested that dietary inclusion of 33% SBM significantly reduced growth and feed utilization, lowered the non-specific immune response and damaged intestinal epithelial morphology compared to 18% SBM. Adding dietary NaB partially reversed these detrimental effects imposed by the increased SBM inclusion.

Modulation of the growth performance, body composition and nonspecific immunity of crucian carp Carassius auratus upon Enteromorpha prolifera polysaccharide

The present study investigated dietary Enteromorpha prolifera polysaccharide (EPP) on the growth performance, body composition and non-specific immunity of crucian carp Carassius auratus. Crucian carps with body weight of 51.24 ± 4.08 g were randomly divided into five groups: one group was fed with basic diet, while the other four groups were fed with diets containing 20, 40, 60 and 80 g/kg EPP. After 60 days of feeding, dietary administration of 40 g/kg EPP increased the body weight gain rate, feed conversion ratio, specific growth rate, body crude protein content, intestine digestive enzyme activities, serum lysozyme activity, acid phosphatase activity, alkaline phosphatase activity, complement 3 level, superoxide dismutase activity and catalase activity and decreased body fat content and serum total cholesterol, triacylglycerol, alanine aminotransferase activity and glutamic oxaloacetic transaminase activity compared with those of the control group. All levels of EPP improved the resistance to Aeromonas hydrophilia compared with the control group. The results indicated that EPP could promote the growth of crucian carp and improve their disease resistance and may be used as a dietary supplement for crucian carp.

Effect of antibiotic-free, low-protein diets with specific amino acid compositions on growth and intestinal flora in weaned pigs.

This study investigated the effects of modulation of the amino acid profile on growth performance and gut health in weaned pigs fed an antibiotic-free, low-protein diet. In experiment 1, 5 treatments were included: a control diet with antibiotics; a low-protein diet with antibiotics; a low-protein diet without antibiotics (LP); a LP diet with 10% more dietary essential amino acids (LP110); and an LP110 diet with 12% more dietary Met + Cys, Thr and Trp. The intestinal digestive enzyme activity and morphology were improved with the increase in dietary essential amino acid levels, while the growth performance was decreased, indicating that the dietary amino acid level was too high. In experiment 2, all 5 treatments of experiment 1 were included, plus a LP diet with 5% more dietary essential amino acids (LP105) and an LP105 diet with 6% more dietary Met + Cys, Thr and Trp. The LP105 treatment showed optimal feed efficiency, a reduced plasma endotoxin concentration, and an increased fecal lactate concentration and increased abundances of Prevotellaceae and Roseburia bacteria. Our results demonstrate that the optimal amino acid profile in an antibiotic-free, low-protein diet can efficiently improve growth performance and gut health and modulate the fecal microbial structure in weaned pigs.

The growth performance, intestinal digestive and absorptive capabilities in piglets with different lengths of small intestines

The small intestine is an important digestive organ and plays a vital role in the life of a pig. We tested the hypothesis that the length of the small intestine is related to growth performance and intestinal functions of piglets. A total of 60 piglets (Duroc × Landrace × Yorkshire), weaned at day 21, were fed an identical diet during a 28-day trial. At the end of the study, all piglets were sacrificed, dissected and grouped according to small intestine lengths (SILs), either short small intestine (SSI), middle small intestine (MSI) or long small intestine (LSI), respectively. Positive relationships between SIL and BW, average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratios (G : F) were observed. Final BW, ADG, ADFI and G : F significantly increased (P < 0.05) in MSI and LSI piglets compared with SSI piglets. Short small intestine and MSI had greater jejunal mucosa sucrase and alkaline phosphatase activities (P < 0.05) than LSI piglets. The mRNA level of solute carrier family 2 member 2 (Slc2a2) in the jejunal mucosa of SSI piglets was the greatest. The MSI piglets had a greater (P < 0.05) ileal villus height than other piglets and greater (P < 0.05) villus height-to-crypt depth ratios than LSI piglets. However, the LSI piglets had a greater (P < 0.05) ileal crypt depth than SSI piglets. No significant differences in duodenal, jejunal, caecal and colonic morphologies were detected among the groups. Moreover, luminal acetate, propionate, butyrate and total short-chain fatty acid contents were greater (P < 0.05) in SSI and MSI piglets than those in LSI piglets. In addition, there was greater serum glucose concentration in MSI piglets than other piglets. Serum albumin concentration in SSI piglets was the lowest. In conclusion, these results indicate that SIL was significantly positively associated with growth performance, and in terms of intestinal morphology and mucosal digestive enzyme activity, the piglets with a medium length of small intestine have better digestion and absorption properties.

Fermented wheat bran by xylanase-producing Bacillus cereus boosts the intestinal microflora of broiler chickens

Wheat bran, while a nutritious and economic feed ingredient, contents high levels of non-starch polysaccharides which entraps nutrients and interferes digestion and absorption. To study the influence of fermented wheat bran by xylanase-producing Bacillus cereus on growth performance and intestinal microflora of broiler chickens, a total of 180 broilers (21-day-old, mixed of male and female) were randomly divided into 3 treatments, with 6 replicates in each treatment and 10 broilers in each replicate: 1) control check (CK), corn-soybean meal-based diet; 2) wheat bran group (WB), 5% of the corn were replaced with wheat bran; and 3) fermented wheat bran group (FWB), 5% of the corn were replaced with fermented wheat bran. Growth performance was determined in the period of 21- to 42-day-old. Intestinal digestive enzyme activities and microbiota diversity were analyzed on day 42. No differences were observed on growth performance among treatments (P > 0.05). The activity of amylase in the duodenum of FWB was 1.56 times higher than CK (P < 0.05). The Chao1 index of microbiota in cecum of FWB increased 24.26% compared with CK (P < 0.01). The amount of Bifidobacteriaceae in cecum of WB was 29.1 times and 15.8 times higher than CK and FWB (P < 0.05) respectively. Principal co-ordinates analysis in cecum revealed the dissimilarity microbiota among treatments. In summary, the use of fermented wheat bran to partially replace corn (5%) in diets had no adverse effect on growth performance and triggered beneficial effects such as increasing duodenal amylase activity and intestinal microflora abundance in broiler chickens. These observations support that solid-state fermentation by xylanase-producing Bacillus cereus is feasible approach to pre-treat wheat bran for feedstuff industry.