The effect of NSP-degrading enzymes on gut physiology and growth performance of turkeys fed soybean meal and peas-based diets

Xylanase improves the intestinal barrier function of Nile tilapia (Oreochromis niloticus) fed with soybean (Glycine max) meal

BACKGROUND

Soybean (Glycine max) meal is one of the important protein sources for fish, but the non-starch polysaccharides (NSP) in soybean meal impair the intestinal barrier function. Here we aimed to investigate whether xylanase can alleviate the adverse effects on the gut barrier induced by soybean meal in Nile tilapia and to explore the possible mechanism.

RESULTS

Nile tilapia (Oreochromis niloticus) (4.09 ± 0.02 g) were fed with two diets including SM (soybean meal) and SMC (soybean meal + 3,000 U/kg xylanase) for 8 weeks. We characterized the effects of xylanase on the gut barrier, and the transcriptome analysis was performed to investigate the underlying mechanism. Dietary xylanase improved intestinal morphology and decreased the concentration of lipopolysaccharide (LPS) in serum. The results of transcriptome and Western blotting showed that dietary xylanase up-regulated the expression level of mucin2 (MUC2) which may be related to the inhibition of protein kinase RNA-like endoplasmic reticulum kinase (perk)/activating transcription factor 4 (atf4) signaling pathways. Microbiome analysis showed that addition of xylanase in soybean meal altered the intestinal microbiota composition and increased the concentration of butyric acid in the gut. Notably, dietary sodium butyrate was supplemented into the soybean meal diet to feed Nile tilapia, and the data verified that sodium butyrate mirrored the beneficial effects of xylanase.

CONCLUSIONS

Collectively, supplementation of xylanase in soybean meal altered the intestinal microbiota composition and increased the content of butyric acid which can repress the perk/atf4 signaling pathway and increase the expression of muc2 to enhance the gut barrier function of Nile tilapia. The present study reveals the mechanism by which xylanase improves the intestinal barrier, and it also provides a theoretical basis for the application of xylanase in aquaculture.

Carbohydrate-active enzymes in animal feed

Considering an ever-growing global population, which hit 8 billion people in the fall of 2022, it is essential to find solutions to avoid the competition between human food and animal feed for croplands. Agricultural co-products have become important components of the circular economy with their use in animal feed. Their implementation was made possible by the addition of exogenous enzymes in the diet, especially carbohydrate-active enzymes (CAZymes). In this review, we describe the diversity and versatility of microbial CAZymes targeting non-starch polysaccharides to improve the nutritional potential of diets containing cereals and protein meals. We focused our attention on cellulases, hemicellulases, pectinases which were often found to be crucial in vivo. We also highlight the performance and health benefits brought by the exogenous addition of enzymatic cocktails containing CAZymes in the diets of monogastric animals. Taking the example of the well-studied commercial cocktail Rovabio™, we discuss the evolution, constraints and future challenges faced by feed enzymes suppliers. We hope that this review will promote the use and development of enzyme solutions for industries to sustainably feed humans in the future.

The effect of the dietary inclusion of pea seeds of colored-flowered and white-flowered varieties on gastrointestinal function in turkeys

This study investigated the effects of dietary replacement of soybean meal (SBM) with graded levels of pea seeds (PS) on the gastrointestinal function of turkeys. Seeds of 2 pea varieties, a colored-flowered variety and a white-flowered variety (CFP and WFP, respectively) were fed to 56-d-old birds for 8 wk. A total of 539 female Hybrid turkeys were allocated to 7 groups, each group consisted of 7 pens with 11 birds per pen. The experiment had a 2-factorial design, with 3 dietary inclusion levels of PS (100, 200 and 300 g/kg) and 2 pea varieties (CFP and WFP). The control group (diets without PS) was compared with CFP and WFP treatments by simple contrast analysis. In comparison with CFP seeds, WFP seeds contained 7-fold less tannins (0.67 vs. 4.66 g/kg) and less non-starch polysaccharides (NSP, 117.8 vs. 132.7 g/kg), but more trypsin inhibitors (1.34 vs. 0.98 g/kg) and starch (489 vs. 455 g/kg). A rise in the PS content of diets from 100 to 200 and 300 g/kg increased the weight of the small intestine (P = 0.031) and the dry matter (DM) content of intestinal digesta (P = 0.001), but it had no effect on the pH of digesta. Only the highest PS content differentiated the concentrations of short-chain fatty acids (SCFAs) in the small intestinal digesta (WFP > CFP, P = 0.008), whereas PS did not cause any changes in the morphological parameters of the small intestinal mucosa. The dietary inclusion of PS had no influence on the levels of acetate, butyrate, putrefactive SCFAs or total SCFAs in the cecal contents. Apart from increasing the activities of β-glucosidase (P = 0.017) and β-galactosidase (P = 0.025), pea varieties did not affect the activities of the analyzed cecal microbial enzymes. However, CFP seeds decreased the DM content (P = 0.041) and increased the pH of cecal digesta, compared with WFP seeds (P = 0.013). The results of this study, pointing to a few differences in the functional parameters of the small intestine and cecum, indicate that tannins are not a factor differentiating the suitability of CFP and WFP seeds in the nutrition of finisher turkeys. The inclusion of PS at 200 and 300 g/kg of the diet reduces the content of SBM and wheat in turkey diets, which has a positive effect on gastrointestinal function.

Energy values evaluation and improvement of soybean meal in broiler chickens through supplemental mutienzyme

This study measured the metabolizable energy of soybean meal (SBM) and evaluated effects of soybean meal specific enzymes supplementation in corn-soybean diets on growth performance, intestinal digestion properties and energy values of 28-day-old broilers. A total of 336 one-day-old male AA broiler chickens were distributed to 7 groups in a completely random design. The birds were given 7 diets containing 6 diets with different combined soybean meals and a fasting treatment, 8 replicates per treatment and 6 birds per replicate (Trial 1). A total of 672 one-day-old male AA broiler chickens were randomly allocated to 7 dietary treatments including a control diet and 6 diets supplemented with 300 mg/kg α-galactosidase, 200 mg/kg β-mannanase, and 300 mg/kg protease individually or in combination (Trial 2). Apparent metabolizable energy (AME) of broilers was measured from d 25 to 27 in both trial 1 and trial 2. The results showed that AME values of combined soybean meals averaged 2,894 kcal/kg. Dietary β-mannanase and protease supplementation increased body weight gain (P < 0.05) during d 0 to 14, whereas did not affect the growth performance (P > 0.05) during d 14 to 28. Addition of β-mannanase in combination with other enzymes significantly increased lipase and trypsin content (P < 0.05) in ileum. In addition, dietary β-mannanase and protease supplementation individually or in combination enhanced trypsin enzyme content in jejunum (P < 0.05). The β-mannanase enzyme enhanced villus height and villus height to crypt depth ratio (P < 0.05) of ileum compared with control diet. Moreover, supplementation of enzyme except for protease enhanced raffinose and stachyose degradation ratio (P < 0.05). Dietary β-mannanase supplementation individually or in combination enhanced AME and AMEn values (P < 0.05). This study demonstrated that dietary enzyme supplementation especially β-mannanase improved intestinal digestion properties and contributed to high energy values.

Influence of Supplementation of Lactoferrin, Melittin and Cecropin A to Rat Diet on Changes in Faecal Ammonia Concentrations, Short-Chain Fatty Acid Concentrations and Activities of Bacterial Enzymes

Simple Summary

In the present study conducted on Wistar laboratory rats, the effects of two selected insect antimicrobial peptides (AMPs), melittin and cecropin A, were investigated and compared to those attributed to well-known antibacterial action of lactoferrin. It was hypothesised that the dietary presence of lactoferrin, melittin or cecropin A strongly affects the rat large gut microbial activity at the time of protein/peptide administration and the durability of the effects may differ after their withdrawal from a diet. The experiment was conducted on living animals (without their euthanasia) and the dynamics of changes in pH, microbial enzyme activity, ammonia and short-chain fatty acids concentrations were investigated in the faeces during and after the dietary treatments with lactoferrin, melittin or cecropin A. The results suggested that the faecal intensity of microbial fermentation processes in rats was quickly reduced upon dietary addition of two AMPs and lactoferrin after two days of treatment, on average. The strongest suppression effect was observed on the 5th day of treatment and persisted on days 5–8. The changes caused by the supplemented lactoferrin and AMPs were reversible after 15 days, i.e., 10 days after the withdrawal of lactoferrin, melittin and cecropin A from the diet.

Abstract

We hypothesised that the dietary addition of the bioactive antimicrobial protein lactoferrin (LF) and peptides melittin (MT) or cecropin A (CR) at a dosage of 100 mg/kg to the diet of Wistar rats would result in strong modulatory effects on faecal microbial enzymatic activity, short-chain fatty acid and ammonia concentrations. To date, the changes in bacterial extracellular and intracellular enzymatic activities upon addition of dietary AMPs have not yet been studied. This experiment lasted 15 days; during the first 5 day period, the rats were fed the control diet (S) and diets supplemented with LF, MT or CR. On days 6–15, all rats were fed the control S diet. The faecal fermentation processes were substantially stopped after two days of treatment, on average, in all rats receiving LF and two AMPs. The deepest suppression effect was observed on the last day of treatment (day 5) and persisted through days 5–8. The highest decreases in faecal bacterial β-glucosidase and β-glucuronidase activities as well as in SCFA and ammonia concentrations were observed in the rats fed the CR diet. Only in the CR animals did the mechanism of suppressed microbial fermentation involve diminished enzyme release from bacterial cells to the digesta.