Effects of dietary xylooligosaccharides on the performance, egg quality, nutrient digestibility and plasma parameters of laying hens

Effects of micelle silymarin in corn-soybean meal-based diet on laying hens' performance, egg quality, and blood profile, with comparative assessment of blood absorption rates between powdered and micelle silymarin

Micelle silymarin (MS) is recognized for its diverse range of beneficial properties, which encompass anti-inflammatory, antioxidant, hepatoprotective, and antidiabetic effects. The main objective of this study was to examine the effects of micelle silymarin on the performance, egg quality, blood profile, and absorption rate of silymarin in laying hens. In experiment 1: 288 Hy-Line brown laying hens, 28 wk old, were utilized for this experiment. The hens were randomly allocated into 3 dietary treatment groups, with each group comprising eight replicates of 12 hens, each housed in individual pens with access to feed and water. Over a 12-wk feeding trial, the hens were provided with a basal diet supplemented with different levels of MS: 0, 0.03, and 0.06%. In experiment 2: For this experiment, 192 Hy-Line Brown laying hens were divided into 2 dietary treatment groups, with each group comprising eight replications of 12 hens. The dietary treatments were: TRT1, basal diet + powder silymarin 4%; TRT2, basal diet + MS 4%. From the first experiment, the findings revealed that incorporating micelle silymarin (MS) into the hens' diet significantly increased egg weight at wk 6 (P < 0.05). Similarly, at wk 12 and throughout the entire experiment, significant effects were observed on downgraded egg count, egg production, egg weight, and feed conversion ratio (FCR) (P < 0.05). Moreover, Haugh Units (HU) and albumen height showed a linear improvement (P < 0.05) at wk 4 with MS supplementation. Furthermore, there was a linear increase in egg yolk color, albumen height, and eggshell thickness at wk 8 with MS supplementation (P < 0.05). Furthermore, a layers-fed diet supplemented with MS showed a linear increase (P < 0.05) in HU, egg weight, yolk color, albumen height, eggshell strength, and eggshell thickness in wk 12. Regarding blood profile parameters, the study revealed linear reductions for aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) (P < 0.05), whereas there was a tendency for albumin, triglyceride, and cholesterol (P < 0.10). In the second experiment, it was observed that the blood absorption rate of silymarin was higher in TRT2 compared to TRT1 at 2- and 4-h intervals following administration. In summary, increasing MS supplementation in the diet of laying hens enhanced egg production, egg quality, and blood profile. Additionally, silymarin absorption was higher in its micelle form than in its powder form.

Assessing the influence of micelle silymarin on laying hens' performance, egg quality, water loss and blood profile

Micelle silymarin (MS) is known for its various beneficial properties, including antiswelling, antioxidant, hepatoprotective and antidiabetic effects. The primary goal of this research was to investigate how MS impacts the performance, egg quality, water loss and blood profile of laying hens. 288 Hy-Line brown laying hens, 28 weeks in age, were utilized for this experiment. The hens were randomly allocated into three dietary treatment groups, with each group comprising eight replicates of 12 hens, each housed in individual pens with access to feed and water. Over a 12-week feeding trial, the hens were provided with a basal diet supplemented with different levels of MS: 0%, 0.03% and 0.06%. The results indicated that the inclusion of MS in the hens' diet did not have a significant impact on their performance (p > 0.05). However, Haugh units, egg weight and eggshell strength showed a linear improvement (p < 0.05) throughout the entire trial period with MS supplementation. Furthermore, there was a linear decrease in egg yolk colour and eggshell thickness showed linear improvements (p < 0.05), particularly during Week 8, with MS supplementation. Moreover, layers fed diet supplemented with MS showed a linear increased (p < 0.05) in albumen height and eggshell thickness in Week 12. In addition, egg water loss during Week 12, the third day of incubation, linearly decreased as an effect of the increasing level of the MS in the laying hen's diet (p < 0.05). Regarding blood profile parameters, the study revealed a tendency for alkaline phosphatase to decrease, whereas aspartate aminotransferase and cholesterol levels were linearly decreased (p < 0.05). In summary, increasing the level of MS supplementation in the diet of laying hens appeared to be beneficial in improving egg quality, slight improvement for egg water loss and certain aspects of blood profile parameters, without adversely affecting the hens' growth performance.

Holo-analysis of the effects of xylo-oligosaccharides on broiler chicken performance

1. Xylo-oligosaccharides (XOS) stimulate proliferation of beneficial bacteria in the gastrointestinal tract of broiler chickens. This results in enhanced utilisation of dietary non-starch polysaccharides and increased production of valuable short-chain fatty acids. However, these positive effects do not always translate into improved bird productive performance, with inconsistent performance responses observed between bird trials.2. A holo-analysis was conducted to determine the effects of supplementing XOS into broiler diets on bird feed intake, body weight gain, feed conversion and mortality. This was done by comparing the XOS supplemented treatment to the control treatment. A total of 53 studies which met the criteria for inclusion were used in the analysis.3. The results showed that XOS had a notable positive impact on bird mortality; XOS reduced mortality by 0.69% for every 1% increment in the control group. XOS supplementation induced a positive effect on the feed conversion ratio (FCR). However, the efficacy of XOS at improving FCR was dependent on the efficiency of the control group (performance of the flock), and the concentration of total arabinoxylan, protein and phytase in the diet. There were insufficient data points to predict the effect of XOS on body weight and feed intake.4. In conclusion, the holo-analysis revealed that supplementing XOS to broiler chicken diets reduces bird mortality. XOS can also improve FCR, but the scale of response is dependent on the diet composition and control flock performance. Additional studies are required to confirm the effects of XOS on body weight and feed intake.

Broiler chicken response to xylanase and fermentable xylooligosaccharide supplementation

A study was conducted to determine the effect of dietary fiber (DF), xylanase (XYL), xylooligosaccharides (XOS), and a combination of XYL and xylooligosaccharides (STBIO) on chicken growth performance, N-corrected apparent metabolizable energy (AMEn), and nutrient availability, characteristics of the gastrointestinal tract (GIT), and cecal content of short-chain fatty acids (SCFA). A 35-day experiment was performed on 1,920 as hatched Ross 308 broiler chicks, reared in 96 pens and fed ad libitum. Experimental diets were split into 2 phases: starter (0-21 d) and finisher (22-35 d). There were 2 basal diets, first contained 54% maize and in the second, 5% of the maize was replaced by wheat bran as DF. The diets were split into 4 batches: one of them was used as a control, and each of the others were supplemented either with XYL or XOS or with the STBIO. Each diet was fed to 12 pens following randomization. The data were analyzed in GenStat (20th edition) by ANOVA using a 2 × 4 factorial design. The addition of STBIO improved feed conversion ratio (FCR) and increased weight gain (WG) from 21 to 35 d and from 0 to 35 d (P < 0.05). The inclusion of DF had a negative effect on N and fat retention coefficients at 35 d as well as AMEn and dry matter retention at 21 and 35 d. At 21 d, neutral detergent fiber (NDF) retention was increased when xylanase and STBIO were added to the diet (P < 0.001) and at d 35 the highest retention was noted when the diet was supplemented with DF and XYL or STBIO (P = 0.001). There was no dietary effect on jejunum histomorphometry (P > 0.05). The addition of DF increased the concentration of cecal SCFA in particular valeric and propionic acid at 35-day-old birds (P < 0.05). It can be concluded that addition of STBIO in diet could provide benefits in terms of fiber degradation, WG, and feed efficiency.

Interactions of dietary wheat cultivars and NSP-degrading enzyme on productive performance and egg quality traits

CONTEXT

The nutritional value of enzyme-supplemented wheat-contained diets can be influenced by interactions between wheat cultivar and exogenous enzyme, which in turn cause various effects on the performance of poultry.

AIMS

The effects of diets including various wheat cultivars with or without enzyme on productive performance and egg quality characteristics were evaluated.

METHODS

A total of 270 58-week-old Lohmann LSL-Lite were allocated to 9 experimental dietary groups with 5 replicate cages and 6 birds per each cage. Based on a 4 × 2 factorial arrangement of treatment, nine iso-caloric and iso-nitrogenous experimental diets, including four wheat cultivars (Sardari, Azar 2, Pishgam and Sirvan) with and without enzymes plus a corn-based control diet, were tested in a completely randomized design during an 8-week trial period.

KEY RESULTS

From weeks 58 to 63 and 63 to 67 of age, the hens fed with Sardari-included diet showed the lowest feed intake compared to other groups (p < 0.05). Egg production (EP), feed conversion ratio (FCR) and egg mass (EM) were not influenced by the experimental diets. At the age of 62 weeks, the effect of adding enzyme on egg shape index was significant. Moreover, in sampling week 67, increased eggshell weight (%) was detected in enzyme-supplemented diets compared to diets with no enzyme (10.03 vs. 9.37, respectively). Besides, the shell thickness was the highest in the group fed with Azar 2, and the lowest in the group fed with Sirvan at the age of 67 weeks (p < 0.05). Albumen weights (%) were also significant in some cases. The highest albumen weight was observed in Sirvan-included diet without enzyme on week 62. Reduced yolk weight was detected in enzyme-supplemented Pishgam-included diet on 62 weeks of age (p < 0.05).

CONCLUSIONS

The inclusion of the diets of laying hens with the four tested Iranian wheat cultivars has no negative impact on most productive performance and egg quality indices. Moreover, supplementing the wheat-included diets with non-starch polysaccharidase enzyme (beta-endopower) improved eggshell weight on week 67.

Feeding Behavior, Growth Performance and Meat Quality Profile in Broiler Chickens Fed Multiple Levels of Xylooligosaccharides

A total of 240 1-day-old Arbor Acres broiler chickens were randomly distributed to 4 treatment groups with 6 replicates and 10 birds per replicate. Chickens were fed with corn-soybean meal diet supplementation with additions of 0, 150, 300, and 450 mg/kg XOS for 42 days. At 4 weeks of age, the average feeding time was reduced in the 450 mg/kg XOS group (p < 0.05), and the percentage of feeding time was increased in the 300 mg/kg XOS group (p < 0.05). At 5 weeks of age, broilers fed with 300 mg/kg XOS had increased the percentage of feeding time (p < 0.05), and 450 mg/kg XOS had increased the feeding frequency and percentage of feeding time (p < 0.05). At 6 weeks of age, the feeding frequency was highest in the 450 mg/kg XOS group (p < 0.05). During 4 to 6 weeks of age, the average feeding time was increased in 300 mg/kg XOS group (p < 0.05), the frequency was improved in the 450 mg/kg XOS group (p < 0.05), and the percentage of feeding time was longer in the XOS group than that in the control group (p < 0.05). The average daily gain was improved during days 22-42 and days 1-42 in the 150 mg/kg XOS group (p < 0.05). Broilers fed with 300 mg/kg XOS had an increased eviscerated rate (p < 0.05). The pH45min of breast muscle was highest in the 450 mg/kg XOS group (p < 0.05), as well as the pH45min and pH24h of thigh muscle, which improved in the 300 mg/kg and 450 mg/kg XOS groups (p < 0.05). In addition, the cooking loss of thigh muscle was reduced in the 300 mg/kg XOS group (p < 0.05). In conclusion, dietary supplementation with XOS had positive effects on the feeding behavior, growth performance, and meat quality of broiler chickens.

Effects of dietary Clostridium butyricum and fructooligosaccharides, alone or in combination, on performance, egg quality, amino acid digestibility, jejunal morphology, immune function, and antioxidant capacity of laying hens

The present study was conducted to evaluate the effects of Clostridium butyricum (CB) and fructooligosaccharide (FOS) singly or combined, on performance, egg quality, amino acid digestibility, jejunal morphology, immune function and antioxidant capacity in peak-phase laying hens. A total of 288 Hy-Line Brown laying hens (30 weeks of age) were randomly assigned to 4 dietary groups that included basal diet, basal diet +0.02% of CB (zlc-17: 1 × 10⁹ CFU/g) (PRO), basal diet +0.6% FOS (PRE), and basal diet +0.02% CB + 0.6% FOS (SYN) for 12 weeks. Each treatment had 6 replicates with 12 birds each. The results demonstrated that probiotics (PRO), prebiotics (PRE) and synbiotics (SYN) (p ≤ 0.05), respectively, exerted a positive effect on the performance and physiological response of the birds. There were significant increases in egg production rate, egg weight, egg mass, daily feed intake and reduced number of damaged eggs. and zero mortality rate due to dietary PRO, PRE and SYN (p ≤ 0.05) respectively. Also, feed conversion was improved by PRO (p ≤ 0.05). In addition, egg quality assessment showed that; eggshell quality was increased by PRO (p ≤ 0.05) and albumen indices (Haugh unit, thick albumen content, and albumen height) were enhanced by PRO, PRE and SYN (p ≤ 0.05). Further analysis showed that PRO, PRE and SYN (p ≤ 0.05), reduced heterophil to lymphocyte ratio, increased antioxidant enzymes and immunoglobulin concentration. Although spleen index was higher for PRO (p ≤ 0.05) group. The significant increase in villi height, villi width, villi height to crypt depth ratio and reduced crypt depth were obvious for PRO, PRE, and SYN (p ≤ 0.05). Furthermore, improved nutrient absorption and retention evidenced by increased digestibility of crude protein and amino acids, were notable for PRO, PRE, and SYN (p ≤ 0.05) group. Collectively, our findings revealed that dietary CB and FOS alone, or combined, enhanced productive performance, egg quality, amino acid digestibility, jejunal morphology, and physiological response in peak-phase laying hens. Our results would provide direction on nutritional strategies for gut enhancers and better physiological response of peak laying hens.

The preparation technology and application of xylo-oligosaccharide as prebiotics in different fields: A review

Xylo-oligosaccharide (XOS) is a class of functional oligosaccharides that have been demonstrated with prebiotic activity over several decades. XOS has several advantages relative to other oligosaccharide molecules, such as promoting root development as a plant regulator, a sugar supplement for people, and prebiotics to promote intestinal motility utilization health. Now, the preparation and extraction process of XOS is gradually mature, which can maximize the extraction and avoid waste. To fully understand the recent preparation and application of XOS in different areas, we summarized the various technologies for obtaining XOS (including acid hydrolysis, enzymatic hydrolysis, hydrothermal pretreatment, and alkaline extraction) and current applications of XOS, including in animal feed, human food additives, and medicine. It is hoped that this review will serve as an entry point for those looking into the prebiotic field of research, and perhaps begin to dedicate their work toward this exciting classification of bio-based molecules.

The effects of xylo-oligosaccharides on regulating growth performance, nutrient utilization, gene expression of tight junctions, nutrient transporters, and cecal short chain fatty acids profile in Eimeria-challenged broiler chickens

A 21-d experiment was conducted to investigate the effects of xylo-oligosaccharides (XOS) on growth performance, nutrient utilization, gene expression of tight junctions, nutrient transporters, and cecal short chain fatty acids (SCFA) profile of broiler chickens challenged with mixed Eimeria spp. Two hundred fifty-two zero-day-old chicks were allocated to 6 treatments in a 3 × 2 factorial arrangement (corn-soybean meal diets supplemented with 0, 0.5, or 1.0 g/kg XOS; with or without Eimeria challenge). Challenged groups were inoculated with a solution containing E. maxima, E. acervulina, and E. tenella oocysts on d 15. During the infection period (d 15 to d 21), there was a significant (P < 0.05) Eimeria × XOS interaction for weight gain (WG). XOS significantly (P < 0.05) increased WG in the unchallenged birds but not in the challenged treatments. There was no significant Eimeria × XOS interaction for N and minerals utilization responses. XOS supplementation at 0.5 g/kg tended to alleviate Eimeria-induced depression in apparent ileal digestibility of DM (P = 0.052). Challenged birds had lower (P < 0.01) AME, AMEn, and total retention of N, Ca, and P. Eimeria upregulated (P < 0.01) gene expression of tight junction proteins claudin-1, junctional adhesion molecule-2, and glucose transporter GLUT1; but downregulated (P < 0.01) the peptide transporter PepT1, amino acid transporters rBAT, CAT2, y+LAT2, and zinc transporter ZnT1. XOS alleviated (P < 0.05) Eimeria-induced claudin-1 upregulation. Eimeria decreased (P < 0.05) cecal saccharolytic SCFA acetate, butyrate, and total SCFA, but increased (P < 0.05) branched chain fatty acids isobutyrate and isovalerate. The supplementation of XOS tended to decrease the concentration of isobutyrate (P = 0.08) and isovalerate (P = 0.062). In conclusion, 0.5 g/kg XOS supplementation alleviated depression in growth performance and nutrient utilization from the Eimeria challenge. In addition, supplemental XOS reversed the gene expression changes of claudin-1, also showed the potentials of alleviating the negative cecal fermentation pattern induced by Eimeria infection.

Dietary Fructooligosaccharides Effectively Facilitate the Production of High-Quality Eggs via Improving the Physiological Status of Laying Hens

The focus of this study was to investigate the influence of prebiotics, such as fructooligosaccharides (FOS), on laying performance, egg quality, apparent fecal amino acid digestibility, jejunal morphology, hematological indices, immunological response, and antioxidant capacity in laying hens. A total of 216 healthy Hy-Line Brown laying hens aged 30 weeks were randomly assigned to one of three dietary treatments: basal diet, basal diet supplemented with 0.3 percent FOS, or 0.6 percent FOS. For 84 days, each treatment was fed the corresponding experimental diet. According to the findings, dietary supplementation with FOS enhanced laying performance and egg mass while lowering mortality rate. Albumen height, thick albumen content, Haugh unit, and eggshell thickness were also improved by the prebiotics. Prebiotics also boosted antioxidant status by increasing the activity of antioxidant enzymes, improved morphological development of the jejunum as demonstrated by significant increases in villi height, villi width, ratio of villi height to crypt depth, and reduced crypt depth. The prebiotics group showed a considerable increase in immunoglobulin M, G, and A (IgM, IgG, and IgA) levels, as well as a similar effect on complement proteins (C3). Furthermore, the apparent fecal amino acid digestibility of most essential amino acids was significantly enhanced. Conclusively, fructooligosaccharides at inclusion level of 0.6% efficiently enhanced laying performance and production of high-quality eggs while positively modulating amino acid digestibility, jejunal morphology, antioxidant status, and immune functions of the laying hens.

Effects of Dietary Supplementation with Red Yeast (Sporidiobolus pararoseus) on Productive Performance, Egg Quality, and Duodenal Cell Proliferation of Laying Hens

Simple Summary

The present study investigated the effect of different levels of red yeast added to the diet of laying hens as a substitute for antibiotics. The aim of this study is to measure growth performance, egg quality, and small intestinal health of hens receiving this supplement at various levels during 22–60 weeks of age. The results indicate that supplementation with dietary red yeast has a positive effect on productivity and gut health; thus, we suggest administration of this additive as a substitute for antibiotics in laying hens.

Abstract

Nowadays, industrial poultry producers are more focused on the safety of their products, especially contaminants from feedstuffs such as mycotoxin and pesticides. The residue from animal production using antibiotic growth promoters (AGPs) may cause some problems with antimicrobial resistance in human and animals. Red yeast (Sporidiobolus pararoseus) has a cell wall consisting of β-glucan and mannan-oligosaccharides and pigments from carotenoids that may be suitable for use as a substitute for AGPs. The objective was to evaluate the effects of red yeast in laying hen diets on productive performance, egg quality, and duodenal health. A total of 22-week-old laying hens (n = 480) were divided into five groups: control diet (CON), AGP at 4.5 g/kg and red yeast supplementation at 1.0 (RY1.0), 2.0 (RY2.0) and 4.0 g/kg (RY4.0) of diet. The results show that the AGP, RY2.0, and RY4.0 groups had significantly higher final body weight compared with the other groups (p < 0.001). The red yeast supplementation improved the egg shape index (p = 0.025), Haugh unit (p < 0.001), and yolk color (p = 0.037), and decreased yolk cholesterol (p < 0.001). Diet with red yeast supplementation improved villus height to crypt depth ratio and crypt cell proliferations. In conclusion, red yeast supplementation at 2.0 g/kg of diet can substitute AGP in layer diet.

Xylo-Oligosaccharides, Preparation and Application to Human and Animal Health: A Review

Xylo-oligosaccharides (XOS) are considered as functional oligosaccharides and have great prebiotic potential. XOS are the degraded products of xylan prepared via chemical, physical or enzymatic degradation. They are mainly composed of xylose units linked by β-1, 4 bonds. XOS not only exhibit some specific physicochemical properties such as excellent water solubility and high temperature resistance, but also have a variety of functional biological activities including anti-inflammation, antioxidative, antitumor, antimicrobial properties and so on. Numerous studies have revealed in the recent decades that XOS can be applied to many food and feed products and exert their nutritional benefits. XOS have also been demonstrated to reduce the occurrence of human health-related diseases, improve the growth and resistance to diseases of animals. These effects open a new perspective on XOS potential applications for human consumption and animal production. Herein, this review aims to provide a general overview of preparation methods for XOS, and will also discuss the current application of XOS to human and animal health field.

Characterization of a novel GH10 xylanase with a carbohydrate binding module from Aspergillus sulphureus and its synergistic hydrolysis activity with cellulase

A study was carried out to investigate the characterization of a novel Aspergillus sulphureus JCM01963 xylanase (AS-xyn10A) with a carbohydrate binding module (CBM) and its application in degrading alkali pretreated corncob, rapeseed meal and corn stover alone and in combination with a commercial cellulase. In this study, the 3D structure of AS-xyn10A, which contained a CBM at C-terminal. AS-xyn10A and its CBM-truncated variant (AS-xyn10A-dC) was codon-optimized and over-expressed in Komagaella phaffii X-33 (syn. Pichia pastoris) and characterized with optimal condition at 70 °C and pH 5.0, respectively. AS-xyn10A displayed high activity to xylan extracted from corn stover, corncob, and rapeseed meal. The concentration of hydrolyzed xylo-oligosaccharides (XOSs) reached 1592.26 μg/mL, 1149.92 μg/mL, and 621.86 μg/mL, respectively. Xylobiose was the main product (~70%) in the hydrolysis mixture. AS-xyn10A significantly synergized with cellulase to improve the hydrolysis efficiency of corn stover, corncob, and rapeseed meal to glucose. The degree of synergy (DS) was 1.32, 1.31, and 1.30, respectively. Simultaneously, XOSs hydrolyzed with AS-xyn10A and cellulase was improved by 46.48%, 66.13% and 141.45%, respectively. In addition, CBM variant decreased the yields of xylo-oligosaccharide and glucose in rapeseed meal degradation. This study provided a novel GH10 endo-xylanase, which has potential applications in hydrolysis of biomass.

Friend or Foe? Impacts of Dietary Xylans, Xylooligosaccharides, and Xylanases on Intestinal Health and Growth Performance of Monogastric Animals

This paper discusses the structural difference and role of xylan, procedures involved in the production of xylooligosaccharides (XOS), and their implementation into animal feeds. Xylan is non-starch polysaccharides that share a β-(1-4)-linked xylopyranose backbone as a common feature. Due to the myriad of residues that can be substituted on the polymers within the xylan family, more anti-nutritional factors are associated with certain types of xylan than others. XOS are sugar oligomers extracted from xylan-containing lignocellulosic materials, such as crop residues, wood, and herbaceous biomass, that possess prebiotic effects. XOS can also be produced in the intestine of monogastric animals to some extent when exogenous enzymes, such as xylanase, are added to the feed. Xylanase supplementation is a common practice within both swine and poultry production to reduce intestinal viscosity and improve digestive utilization of nutrients. The efficacy of xylanase supplementation varies widely due a number of factors, one of which being the presence of xylanase inhibitors present in common feedstuffs. The use of prebiotics in animal feeding is gaining popularity as producers look to accelerate growth rate, enhance intestinal health, and improve other production parameters in an attempt to provide a safe and sustainable food product. Available research on the impact of xylan, XOS, as well as xylanase on the growth and health of swine and poultry, is also summarized. The response to xylanase supplementation in swine and poultry feeds is highly variable and whether the benefits are a result of nutrient release from NSP, reduction in digesta viscosity, production of short chain xylooligosaccharides or a combination of these is still in question. XOS supplementation seems to benefit both swine and poultry at various stages of production, as well as varying levels of XOS purity and degree of polymerization; however, further research is needed to elucidate the ideal dosage, purity, and degree of polymerization needed to confer benefits on intestinal health and performance in each respective species.

Effects of multicarbohydrase and butyrate glycerides on productive performance, nutrient digestibility, gut morphology, and ileal microbiota in late-phase laying hens fed corn- or wheat-based diets

A study was undertaken to determine the effects of supplemental multicarbohydrase (MC) and butyrate glycerides (BG) on productive performance, nutritional, and physiological responses in laying hens fed corn- or wheat-based diets during a 12-week production period (from 50–62 wk of age). The experiment consisted of a 2 × 2 × 2 factorial arrangement of the treatments with 2 different basal diets (corn- or wheat-based diets), 2 concentrations of MC (0 or 200 mg/kg of diet), and 2 concentrations of BG (0 or 2 g/kg of diet). Each treatment had 6 replicates with 8 hens each. The interactions among diet, MC, and BG were observed for egg production (P = 0.048), feed conversion ratio (P = 0.005), and ileal Escherichia coli count (P = 0.043), indicating that the effects of MC and BG on these responses were more marked when wheat-based diet was fed. A diet × MC interaction (P < 0.05) was also detected for egg mass, eggshell breaking strength, jejunal viscosity, and digestibility coefficients of fat and ash. Replacing 100% of the corn with wheat in the diets of laying hens negatively affected (P < 0.05) yolk color index, eggshell thickness, digesta viscosity, jejunal morphology, and populations of ileal microbiota. By contrast, MC supplementation increased (P < 0.05) eggshell thickness, digestibility coefficients of energy and crude protein, and populations of Lactobacillus and Bifidobacterium spp. in the ileum. Inclusion of BG also resulted in greater (P < 0.05) jejunal villus height and villus surface area, and digestibility coefficients of protein and ash, but lower (P < 0.05) populations of total bacteria, Salmonella and E. coli in the ileum. Results indicate that while the complete substitution of corn by wheat has a detrimental effect on productive performance and gut health, the combination of MC and BG may have synergistic effects on improving productive performance and intestinal microbiota in laying hens fed the wheat-based diets during the late laying period.

Dietary supplemental xylooligosaccharide modulates nutrient digestibility, intestinal morphology, and gut microbiota in laying hens

This study was conducted to evaluate the prebiotic effects of dietary xylooligosaccharide (XOS) supplementation on performance, nutrient digestibility, intestinal morphology, and gut microbiota in laying hens. In a 12-wk experiment, a total of 288 Hy-Line Brown layers at 50 wk of age were randomly assigned into 3 dietary treatments supplemented with XOS at 0, 200 or 400 mg/kg. Each treatment had 8 replicates with 12 birds each. Hens fed XOS diets showed a lower feed-to-egg ratio during wk 7 to 12 and a higher egg yolk color value in wk 12 compared with those fed the control diet (P < 0.05). Dietary XOS supplementation improved the apparent total tract digestibility of gross energy and nitrogen at the end of the 12th wk (P < 0.05). In addition, a higher villus height-to-crypt depth ratio of the ileum was observed in XOS-added groups (P < 0.05). The high throughput sequencing analysis of bacterial 16S rRNA revealed that dietary XOS supplementation at 200 mg/kg altered cecal microbiota. Alpha diversity analysis illustrated a higher cecal bacterial richness in birds fed with XOS at 200 mg/kg. The composition of cecal microbiota modulated by the XOS addition was characterized by an increased abundance of Firmicutes along with a reduced abundance of Bacteroidetes. At the genus level, dietary XOS supplementation triggered decreases in Bacteroides and Campylobacter concurrent with increases in Lactobacillus and several short chain fatty acid producers including Desulfovibrio, Faecalitalea, Faecalicoccus, and 5 genera of family Lachnospiraceae. Collectively, dietary XOS addition improved the feed conversion ratio by modulating nutrient digestibility and ileal morphology in laying hens, which could be attributed to the enhancement of bacterial diversity and alteration of microbial composition.

Inulin improves the egg production performance and affects the cecum microbiota of laying hens

Egg production performance, egg quality, nutrient digestibility, and microbial composition as affected by dietary inulin supplementation were evaluated in laying hens. A total of 300 laying hens were divided into 5 groups and fed diets containing inulin at levels of 0 (control), 5, 10, 15 and 20 g/kg, respectively. The results showed that the 15 g/kg inulin supplementation level improved average egg weight by 2.54%, egg mass by 5.76%, and laying rate by 3.09%, and decreased the feed conversion ratio by 3.61% compared to those of the control during feeding weeks 1 to 8. Dietary inulin supplementation improved eggshell thickness, nutrient digestibility and cecum Bacteroidales_S24-7_ group abundance in the laying hens. In conclusion, dietary inulin supplementation, particularly at the level of 15 g/kg, improved the egg production performance and eggshell thickness of laying hens, mainly due to increased nutrient digestibility and selective modulations of the cecum microbial communities.

The Gut Microbiota of Laying Hens and Its Manipulation with Prebiotics and Probiotics To Enhance Gut Health and Food Safety

The microbiota plays a vital role in maintaining gut health and influences the overall performance of chickens. Most gut microbiota-related studies have been performed in broilers, which have different microbial communities compared to those of layers. The normal gut microbiota of laying chickens is dominated by Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Actinobacteria at the phylum level. The composition of the gut microbiota changes with chicken age, genotype, and production system. The metabolites of gut microbiota, such as short-chain fatty acids, indole, tryptamine, vitamins, and bacteriocins, are involved in host-microbiota cross talk, maintenance of barrier function, and immune homeostasis. Resident gut microbiota members also limit and control the colonization of foodborne pathogens. In-feed supplementations of prebiotics and probiotics strengthen the gut microbiota for improved host performance and colonization resistance to gut pathogens, such as Salmonella and Campylobacter The mechanisms of action of prebiotics and probiotics come through the production of organic acids, activation of the host immune system, and production of antimicrobial agents. Probiotic candidates, including Lactobacillus, Bifidobacterium, Bacillus, Saccharomyces, and Faecalibacterium isolates, have shown promising results toward enhancing food safety and gut health. Additionally, a range of complex carbohydrates, including mannose oligosaccharides, fructo-oligosaccharides, and galacto-oligosaccharides, and inulin are promising candidates for improving gut health. Here, we review the potential roles of prebiotics and probiotics in the reshaping of the gut microbiota of layer chickens to enhance gut health and food safety.

Laboratory Evolution of GH11 Endoxylanase Through DNA Shuffling: Effects of Distal Residue Substitution on Catalytic Activity and Active Site Architecture

Endoxylanase with high specific activity, thermostability, and broad pH adaptability is in huge demand. The mutant library of GH11 endoxylanase was constructed via DNA shuffling by using the catalytic domain of Bacillus amyloliquefaciens xylanase A (BaxA) and Thermomonospora fusca TF xylanase A (TfxA) as parents. A total of 2,250 colonies were collected and 756 of them were sequenced. Three novel mutants (DS153: N29S, DS241: S31R and DS428: I51V) were identified and characterized in detail. For these mutants, three residues of BaxA were substituted by the corresponding one of TfxA_CD. The specific activity of DS153, DS241, and DS428 in the optimal condition was 4.54, 4.35, and 3.9 times compared with the recombinant BaxA (reBaxA), respectively. The optimum temperature of the three mutants was 50°C. The optimum pH for DS153, DS241, and DS428 was 6.0, 7.0, and 6.0, respectively. The catalytic efficiency of DS153, DS241, and DS428 enhanced as well, while their sensitivity to recombinant rice xylanase inhibitor (RIXI) was lower than that of reBaxA. Three mutants have identical hydrolytic function as reBaxA, which released xylobiose–xylopentaose from oat spelt, birchwood, and beechwood xylan. Furthermore, molecular dynamics simulations were performed on BaxA and three mutants to explore the precise impact of gain-of-function on xylanase activity. The tertiary structure of BaxA was not altered under the substitution of distal residues (N29S, S31R, and I51V); it induced slightly changes in active site architecture. The distal impact rescued the BaxA from native conformation (“closed state”) through weakening interactions between “gate” residues (R112, N35 in DS241 and DS428; W9, P116 in DS153) and active site residues (E78, E172, Y69, and Y80), favoring conformations with an “open state” and providing improved activity. The current findings would provide a better and more in-depth understanding of how distal single residue substitution improved the catalytic activity of xylanase at the atomic level.

Effect of dietary xylooligosaccharides on intestinal characteristics, gut microbiota, cecal short-chain fatty acids, and plasma immune parameters of laying hens

This study examined the prebiotic effects of xylooligosaccharides (XOS) on intestinal characteristics, gut microbiota, cecal short-chain fatty acids, plasma calcium metabolism, and immune parameters of laying hens. A total of 1,080 White Lohmann laying hens (28 wk of age) was assigned to 6 dietary treatments that included XOS at concentrations of 0, 0.01, 0.02, 0.03, 0.04, or 0.05% for 8 weeks. Each treatment had 6 replicates with 10 cages (3 birds/cage). Blood, intestinal tissues, and cecal digesta samples were collected from chickens at the end of the experiment. Villus height, crypt depth, the villus to crypt (VH: CD) ratio, and the relative length of different intestinal sections were evaluated. Additionally, the number of microorganisms and the content of short-chain fatty acids in cecal digesta samples were determined. Plasma concentrations of immunoglobulin A (IgA), immunoglobulin G, immunoglobulin M (IgM), interleukin 2 (IL-2), tumor necrosis factor-α(TNF-α), 1, 25-dihydroxyvitamin D3 (1,25(OH)2D3), calcitonin (CT), and parathyroid hormone (PTH) were also determined. The results showed that villus height and the VH: CD ratio of the jejunum were increased (linear, P < 0.01) with the increase in dietary XOS concentration, and the relative length of the jejunum (P = 0.03) was increased significantly in XOS diets. Dietary supplementation of XOS significantly increased (linear, P < 0.01) the number of Bifidobacteria in the cecum; however, total bacteria count, Lactobacillus, and Escherichia coli in the cecum were not affected by XOS supplementation. In addition, inclusion of XOS increased (linear, P < 0.01) the content of butyrate in the cecum; and the content of acetic acid showed a linear increasing trend (P = 0.053) with increasing concentration of XOS in the diets. Supplementation with XOS increased (quadratic, P < 0.05) the content of 1,25(OH)2D3 in plasma. There were no significant differences (P > 0.05) in the content of CT and PTH among dietary treatments. Furthermore, dietary XOS increased contents of IgA (linear, P < 0.05), TNF-α (linear, P < 0.05), IgM (linear, P < 0.05; quadratic, P < 0.05), and IL-2 (quadratic, P < 0.05). Taken together, it was suggested that supplemental XOS can enhance the intestinal health and immune function of laying hens by positively influencing the intestinal characteristics, gut microbiota, cecal short-chain fatty acids, and immune parameters.

The influence of selected feed additives on mineral utilisation and bone characteristics in laying hens

The trial with 240 caged ISA Brown laying hens was performed to evaluate the effect of selected feed additives on mineral utilisation as well as biomechanical (breaking strength, yielding load, stiffness) and geometrical (cortex thickness, cross-section area, weight, length) indices of tibia and femur bones. At 26 wks of age the layers were randomly assigned to 10 treatments with 12 replicates (cages) of two birds. In the study a 2 × 5 experimental scheme was used i.e. to 70 wks of age, the layers were fed isocaloric and isonitrogenous experimental diets containing reduced (3.20%) or standard (3.70%) Ca level. The diets with both Ca levels were either not supplemented, or supplemented with the studied feed additives i.e. sodium butyrate, probiotic bacteria, herbal extract blend and chitosan. There were no statistically significant effects of the experimental factors on the indices of the tibia bones. However, the diet with reduced Ca level decreased bone breaking strength, yielding load, stiffness, and mineralisation of the femur bones (P<0.05). The majority of used feed supplements, i.e. probiotic, herb extracts, and chitosan, increased biomechanical indices (breaking strength and yielding load) and mineralisation of the femur bones (P<0.05). Neither dietary Ca level nor feed additives affected dry matter, organic matter, ether extract, N-free extracts, crude fibre and ash digestibility, and P retention and excretion; however, Ca excretion and retention was lower in the hens fed the diets with reduced Ca level (P<0.05). Relative Ca retention (Ca retained as % of Ca intake) was improved by diet supplementation with probiotic, herb extracts and chitosan (P<0.05). In conclusion, this study has shown that decreased Ca dietary level (3.20%) can negatively affect bone quality in layers, while probiotic, herb extracts and chitosan addition may improve the selected biomechanical indices of the femurs, irrespective of Ca dietary concentration.

Performance, egg quality, nutrient digestibility, and excreta microbiota shedding in laying hens fed corn-soybean-meal-wheat-based diets supplemented with xylanase

The aim of this study was to evaluate the effects of dietary levels of xylanase on production performance, egg quality, nutrient digestibility, and excreta microbiota shedding of laying hens in a 12-week trial. Two-hundred-forty Hy-Line brown laying hens (44 wk old) were distributed according to a randomized block experimental design into one of 4 dietary treatments with 10 replicates of 6 birds each. The 4 dietary treatments were corn-soybean-meal-wheat-based diets supplemented with 0, 225, 450, or 900 U/kg xylanase. Daily feed intake, egg production, egg weight, egg mass, feed conversion ratio, and damaged egg rate showed no significant response to increasing xylanase supplementation during any phase (P > 0.05). No significant responses were observed for apparent total tract digestibility of dry matter, nitrogen, or gross energy (P > 0.05). A significant linear increase to increasing xylanase supplementation was seen for lactic acid bacteria numbers, although coliforms and Salmonella counts were not affected. Increasing the dietary xylanase resulted in a significant linear increase in eggshell thickness in wk 3, 6, 9, and 12 (P < 0.05). In addition, a significant linear increase occurred for Haugh unit and albumen height in wk 12 (P < 0.05). In summary, the inclusion of xylanase in corn-soybean-meal-wheat-based diets increased eggshell thickness, Haugh unit, albumen height, and excreta lactic acid bacteria count but had no effect on production performance or nutrient digestibility.