Contribution of protein, starch, and fat to the apparent ileal digestible energy of corn- and wheat-based broiler diets in response to exogenous xylanase and amylase without or with protease

Total replacement of soybean meal with alternative plant-based ingredients and a combination of feed additives in broiler diets from 1 day of age during the whole growing period

The capacity of combinations of feed enzymes, natural betaine and a probiotic, combined with alternative plant-based ingredients, to totally replace soybean meal (SBM) in a broiler diet was evaluated. Day-old Ross 308 males (2,574) were assigned to 9 treatments (13 pens/treatment, 22 birds/pen) in a completely randomized design. All diets were pelleted and fed ad libitum in 4 phases: starter, grower, finisher 1, finisher 2 (0-10, 10-21, 21-35, and 35-42 d of age, respectively). Treatments included: 1) control diet containing SBM (SBM control), supplemented with phytase (PhyG), at 2,000, 1,500, 1000 and 1,000 FTU/kg in each phase and xylanase (X) at 750 U/kg, [crude protein (CP): 23.5%, 22.0%, 20.2% and 19.3% in each phase]; 2) to 5), alternative (ALT), SBM-free diets, containing the same CP level as the control ("CP high"), supplemented with PhyG as in the control, protease (P, 800 U/kg) and in 2) xylanase (750 U/kg) (ALT+PhyG+P+X), 3) xylanase-β-glucanase (XB, 1,200 U/kg and 152 U/kg) (Alt+PhyG+P+XB), 4) XB plus betaine (800 g/ton) (ALT+PhyG+P+XB+Bet), and 5) XB plus a probiotic [150,000 colony forming units (CFU)/g] (ALT+PhyG+P+XB+Prob); 6) to 9) as treatments 2) to 5) but with CP reduced by -2.0 to -1.5% points vs. control ('CP low'). Final (d 42) BW and overall (d 0-42) feed conversion ratio (FCR) of birds fed the SBM control exceeded breeder objectives (+3.8% and -1.9%, respectively). Overall FCR was reduced and d 42 BW increased in birds fed "low" vs. "high" CP (P < 0.01). Overall FCR and feed intake were not different in ALT+PhyG+XB+P+Bet and ALT+PhyG+XB+P+Prob vs. the control, whereas final BW was reduced (P < 0.05) in all ALT treatments but close to breeder objectives (98.3%) in ALT+PhyG+XB+P+Prob. Feed costs of this treatment were similar to the control. Total replacement of SBM with alternative plant-based ingredients in a CP-low diet supplemented with hydrolytic enzymes and probiotics can achieve growth performance outcomes close to commercial breeder objectives.

A review on the alternatives to antibiotics and the treatment of antibiotic pollution: Current development and future prospects

Antibiotics, widely used in the fields of medicine, animal husbandry, aquaculture, and agriculture, pose a serious threat to the ecological environment and human health. To prevent antibiotic pollution, efforts have been made in recent years to explore alternative options for antibiotics in animal feed, but the effectiveness of these alternatives in replacing antibiotics is not thoroughly understood due to the variation from case to case. Furthermore, a systematic summary of the specific applications and limitations of antibiotic removal techniques in the environment is crucial for developing effective strategies to address antibiotic contamination. This comprehensive review summarized the current development and potential issues on different types of antibiotic substitutes, such as enzyme preparations, probiotics, and plant extracts. Meanwhile, the existing technologies for antibiotic residue removal were discussed under the scope of application and limitation. The present work aims to highlight the strategy of controlling antibiotics from the source and provide valuable insights for green and efficient antibiotic treatment.

Different fat-to-fiber ratios by changing wheat inclusion level impact energy metabolism and microbial structure of broilers

Introduction

Dietary nutrient content is crucial for energy metabolism and development of gut microbiota. Herein, this study aimed to explore the effects of fat-to-fiber ratios on nutrient transporter, energy metabolism and gut microbiota when ingredients composition was altered.

Methods

A total of 240 as-hatched broiler chickens were randomly assigned into three groups including low fat-high dietary fiber (LF-HD), medium fat-medium dietary fiber (MF-MD) and high fat-low dietary fiber (HF-LD), with diets being iso-protein, and broilers were offered the same commercial diets from 21 to 42 d. The data were analyzed using one-way ANOVA of SPSS.

Results and Discussion

Results showed that HF-LD diet significantly increased glucose content and decreased triglyceride in serum of broilers (p < 0.05). The mRNA abundance of jejunal gene involved in glucose transporter and tricarboxylic acid (TCA) cycle was significantly increased in broilers fed with HF-LD diets. Compared with LF-HD, HF-LD had a lower abundance of Anaerofilum and CHKCI001, and an increased proportion of beneficial bacteria such as Alistipes, Catenibacillus, Intestinimonas, Lactobacillus, and Peptococcus (p < 0.05). Functional prediction of these microbial changes indicated that HF-LD diet drove caecal microbiota to participate in carbohydrate metabolism and TCA cycle (p < 0.05). Dietary HF-LD-induced microbiota changes were positively correlated with growth performance of broilers (p < 0.05). Therefore, HF-LD diet increased glucose transporters and energy metabolism in intestine and shaped microbial structure and metabolic pathways, which may benefit the growth performance of broilers.

Application of enzyme matrix values for energy and nutrients to a wheat-corn-soybean meal-based broiler diet supplemented with a novel phytase, with or without a xylanase-β-glucanase, achieved a production benefit over a nutritionally adequate unsupplemented diet

The effect of applying an energy and nutrient matrix to a wheat-corn-soybean meal-based diet supplemented with a novel consensus bacterial 6-phytase variant (PhyG) and xylanase-β-glucanase on growth performance, bone mineralization, carcass weights, feed costs, and carbon footprint was evaluated. A randomized complete block design (3,300 Ross 308 mixed-sex birds; 60 pens, 12 pens per treatment) tested 5 treatments: 1) a positive control diet (PC), containing 0.92, 0.84, 0.71% Ca and 0.43, 0.38, 0.30% digestible P during 1 to 10, 11 to 21, and 22 to 32 d of age, respectively; 2) a negative control reduced in Ca, digestible P, digestible AA, ME, and Na by phase based on the PhyG dosing regimen (NC1); 3) NC1 supplemented with PhyG at 2,000, 1,500, and 1,000 FTU/kg by phase (NC1+PhyG); 4) as NC1 but additionally reduced in ME (NC2); and 5) NC2 supplemented with PhyG as in 3) plus 1,220 U/kg of xylanase and 152 U/kg of β-glucanase (NC2+PhyG+XB). Final (d 32) BW, overall (0-32 d of age) ADFI, FCR, d 10 and 32 tibia ash and carcass part weights were reduced or impaired (P < 0.05) in NC1 and NC2 vs. PC (d 32 BW -477 g/bird (23.4%) and -422 g/bird (20.7%), respectively). Growth performance (all measures, all phases) was improved and tibia ash (at 10 and 32 d of age), total carcass thigh, breast and leg weights were increased (P < 0.05) in NC1+PhyG vs. NC1, and NC2+PhyG+XB vs. NC2. Overall growth performance outcomes in NC1+PhyG and NC2+PhyG+XB were not different (P > 0.05) from the PC. Total feed cost and carbon footprint per kilogram BW gain (BWG) were reduced (P < 0.05) vs. PC in NC2+PhyG+XB [-0.052 € and -376 g CO2 eq./kg BWG, respectively] and NC1+PhyG [-0.038 € and -260 g CO2 eq./kg BWG, respectively]. The results validated the nutrient matrices in the test diets and highlighted a potential feed cost and environmental sustainability benefit which was greatest when the enzymes were applied in combination.

Dietary supplementation with different alternative to in-feed antibiotic improves growth performance of broilers during specific phases

The effects of substituting Bacillus subtilis, Astragalus membranaceus, and enzymes for aureomycin to improve the growth performance of broilers during specific phases were studied to develop alternatives to in-feed antibiotics and decrease drug residues in meat food and antibiotic resistance. Six hundred one-day-old broilers were randomly assigned to 5 groups. Broilers in the control group were supplied with basal diets (CT), and those in the remaining 4 groups were supplied with feed containing aureomycin premix (AU), B. subtilis powder (BS), A. membranaceus root powder (AM), and enzyme compound powder (EN), respectively. Compared to the control group, broilers in the other groups exhibited better growth performance during different phases. Microbial analysis of cecal contents suggested that treatment with BS or EN significantly increased the abundance of Lactobacillus or Bifidobacteria but inhibited Escherichia coli or Clostridium welchii; however, these bacteria were suppressed by AU treatment except C. welchii. The digestibility of the feed in vitro was significantly enhanced by adding BS or EN to the feed, consistent with findings for growth performance. In conclusion, dietary supplementation with 3 additives could improve the growth performance of broilers during specific phases. Future studies should focus on designing suitable schedules to partially replace in-feed antibiotics.

Dietary muramidase increases ileal amino acid digestibility of wheat and corn-based broiler diets without affecting endogenous amino acid losses

The objective of these studies was to evaluate the impact of dietary muramidase (MUR) on endogenous amino acids (AA) losses and digestibility of nutrients in wheat and corn-based broiler diets. In experiment 1, the effect of dietary MUR on the flow of endogenous AA (EAA) at the jejunum and terminal ileum of broilers were assessed using either the nitrogen (N) free diet method (NFD) or the highly digestible protein diet method (HDP; 100 g casein/kg diet). Sialic acid and muramic acid concentrations were measured in the jejunal content. In experiment 2, a 2x2x2 factorial arrangement of treatments with 2 base grains (wheat or corn), with low or high metabolizable energy (ME) levels, and without or with MUR supplementation was implemented. All diets contained phytase, xylanase, and cellulase. Apparent ileal digestibility (AID) of dry matter (DM), protein (CP), amino acids (AA), crude fat, and energy, as well as the apparent total tract metabolizability (ATTM) of DM, CP, and gross energy (GE) were determined. The standardized ileal digestibility (SID) of AA was obtained by correcting AID values for basal ileal EAA obtained from chicks fed with NFD or HDP in experiment 1, jejunal EAA flow of all AA was higher (P < 0.001) compared to the ileum, but this effect was method dependent. Jejunal, but not ileal, EAA flow measured with HDP was higher compared to NFD, as well as sialic acid (P < 0.001) and muramic acid (P < 0.004) concentrations. Muramidase inclusion had no effect on basal EAA flow, independently of the segment and the method used. In experiment 2, dietary MUR supplementation increased the AID of CP (P < 0.05), all AA, and tended (P = 0.07) to increase the AID of GE, independently of the cereal type used. However, ATTM of DM and GE, but not CP, increased with MUR inclusion compared with the control treatments, especially in wheat and low ME diets (P < 0.05). In conclusion, MUR supplementation improved AID of CP and AA without affecting EAA losses and increases energy utilization.

Supplementation of multi-enzymes alone or combined with inactivated Lactobacillus benefits growth performance and gut microbiota in broilers fed wheat diets

The effects of multi-enzymes mixture supplementation or combination with inactivated Lactobacillus on growth performance, intestinal barrier, and cecal microbiota were investigated in broilers at the age of 15-42 days fed a wheat-based diet. A total of 576 broilers (12 broilers/cage; n = 12) were used and divided into four groups and randomly allotted to four experimental diets throughout grower (15-28 days of age) and finisher (29-42 days of age) phases. Diets consisted of a corn-soybean meal-based diet (BD), a wheat-soybean meal-based diet (WD), and WD supplemented multi-enzymes (WED) or combined with inactivated Lactobacillus (WEPD). The results showed that the average daily gain (ADG) and body weight (BW) were reduced in broilers fed WD diet compared with those fed BD diet during the grower period (P < 0.05). Broilers in the WED or WEPD group had higher ADG and BW during the grower period (P < 0.05) and had a lower feed-to-gain ratio (F/G) compared to broilers in the WD group during the grower and overall periods (P < 0.05). Improved expression of intestinal barrier genes (claudin-1, ZO-1, and mucin-2) was observed in WEPD compared to the BD or WD group (P < 0.05). Compared to the BD group, the WD group decreased the abundance of Oscillospira, norank_f__Erysipelotrichaceae, and Peptococcus, which are related to anti-inflammatory function and BW gain. The WD also increased Bifidobacterium and some short-chain fatty acid (SCFA)-producing bacteria (Anaerotruncus, Blautia, and Oscillibacter), and Barnesiella, which were presumed as "harmful microbes" [false discovery rate (FDR) < 0.05]. WED and WEPD groups, respectively, improved Bilophila and Eubacterium_hallii_group compared with those in the WD group (FDR < 0.05). In addition, the Enterococcus abundance was reduced in the WEPD group compared to the WD group (FDR < 0.05). Higher acetate and total SCFA concentrations were observed (P < 0.05) among broilers who received a WD diet. Compared with the WD group, the WED or WEPD group further increased cecal propionate content (P < 0.05) and tended to improve butyrate concentration. These results suggested that supplemental multi-enzymes alone and combined with inactivated Lactobacillus could improve the growth performance based on the wheat-based diet and offer additional protective effects on the intestinal barrier function of broilers.

Responses of Combined Non-starch Polysaccharide Enzymes and Protease on Growth Performance, Meat Quality, and Nutrient Digestibility of Yellow-Feathered Broilers Fed With Diets With Different Crude Protein Levels

The aim of this study was to investigate the responses of non-starch polysaccharide (NSP) enzymes and protease combination on growth performance, meat quality, and nutrients digestibility of yellow-feathered broilers fed with corn-soybean meal basal diets with normal and subnormal crude protein (CP) levels. The experimental design was completely randomized with a 2 × 2 factorial arrangement of treatments, including six replicates of 20 birds per pen. Two basal diets were formulated with normal CP level as positive control (PC) and subnormal CP level without extra essential amino acid (AA) supplementation as negative control (NC). The basal diets were supplemented without or with NSP enzymes and protease. Broilers fed with the NC diet had lower (P < 0.05) final body weight (BW), average daily weight gain (ADG) on days 1–21, 22–56 and 1–56 and higher (P < 0.05) feed-to-gain ratio (F/G) on day 22–56 than those fed with PC diet. The broilers fed with the NC diet had higher (P < 0.05) L^* and b^* values in thigh muscle, crypt depth in the duodenum, and dry matter (DM) digestibility as well as lower (P < 0.05) villus height, musculature thicknesses, and villus height: crypt depth in the duodenum than those fed with the PC diet. Dietary NSP enzymes and protease combination increased (P < 0.05) the ADG and F/G of the broilers on days 1–56, and pH values in breast and thigh muscles as well as the digestibility of DM, gross energy (GE), CP and most AAs of the broilers on day 56. Compared with the PC diet, the combination of NSP enzymes and protease exhibited greater (P < 0.05) improvements in the digestibility of DM, CP, and some AAs (Asp, Ile, and Leu) in the broilers fed with the NC diet. In conclusion, reducing CP diet without essential AA supplementation impaired the growth performance and meat color of the thigh muscles of the broilers. The combination of NSP enzymes and protease effectively improved the growth performance, meat quality, and nutritional values of the broilers. In terms of the digestibility of DM, CP, and some AAs, the magnitude of response to the addition of NSP enzymes and protease was greater in the low nutritional-quality diet with a subnormal CP level.

A novel consensus bacterial 6-phytase variant added to phytate-rich diets totally replaced inorganic phosphate in broilers

The capacity of a novel bacterial 6-phytase variant (PhyG) to totally replace dietary supplemental inorganic phosphate (Pi) in broilers aged one day old was evaluated using a phased dosing strategy and reduction in dietary phytate. A total of 1,248 one-day-old Ross 308 broilers were assigned to 24 pens (52 birds/pen, 12 pens/diet, six each males and females) in a complete randomised block design with a 2×2 factorial arrangement (two diets, two genders). Diets comprised: (1) a positive control (PC) based on maize, wheat and soybean meal, containing Pi from monocalcium phosphate and 2,000 XU/kg xylanase, and; (2) an inorganic phosphate-free (IPF) diet equivalent to PC but with reduced Ca (-2.0 g/kg) and supplemented with PhyG at 3,000, 2,000 and 1000 FTU/kg from d 0 to 11 (3.4 g/kg phytate-P (PP)), d 11 to 22 (3.3 g/kg PP) and d 22 to 42 (2.8 to 2.9 g/kg PP), respectively. A negative control was not included for animal welfare reasons. Tibias were collected on d 11, 22 and 42 from two birds/pen. Treatment IPF maintained or improved average daily gain (ADG), average daily feed intake and feed conversion ratio (FCR) vs PC during all phases; Body weight was higher in the IPF treatment than the PC at d 42 (+3.97%, P<0.01) and ADG during d 0 to 42 (+4.10%, P<0.01). Overall (d 0 to 42), treatment IPF improved FCR in males (-5 points vs PC, P<0.05) but not females. Tibia ash was equivalent in IPF and PC throughout, with no gender differences. In conclusion, when applied as a phased dosing strategy to diets with graded reduction in PP content, PhyG totally replaced supplemental Pi during all growth phases in males and females.

Effect of multi-enzymes supplementation on growth performance, meat quality, ileal digestibility, digestive enzyme activity and caecal microbiota in broilers fed low-ME diet

Objective

Methods

Results

Conclusion

Multi-Enzyme Supplementation Modifies the Gut Microbiome and Metabolome in Breeding Hens

Laying and reproductive performance, egg quality, and disease resistance of hens decrease during the late laying period. Exogenous enzymes promote nutrient digestibility and utilization and improve the intestinal environment. However, the specific regulation of the gut microbiome and metabolome by exogenous enzymes remains unelucidated. This study was conducted to evaluate effects of dietary multi-enzyme supplementation on egg and reproductive performance, egg quality, ileum microbiome, and metabolome of breeders. Here, 224 Hy-Line Brown breeding hens (55 weeks old) were randomly allocated to two groups: dietary controls fed basal diet (DC), and test hens fed 0.2 g/kg corn enzyme diet (CE). Serum levels of total protein, globulin, immunoglobulin Y, and antibodies against the Newcastle disease virus and avian influenza H9 strain were significantly increased (p < 0.05). Egg albumen height, Haugh unit, and fertilization and hatching rates were also significantly increased (p < 0.05) in the CE-fed group. 16S rRNA sequence analysis showed that CE strongly affected both α- and β-diversity of the ileal microbiota. LEfSe analysis revealed that the potentially beneficial genera Lactobacillus, Enterococcus, Faecalicoccus, and Streptococcus were enriched as biomarkers in the CE-fed group. Microbial functional analysis revealed that the functional genes associated with harmful-substance biodegradation was significantly increased in the CE-fed group. Additionally, Spearman correlation analysis indicated that changes in microbial genera were correlated with differential metabolites. In summary, dietary multi-enzyme addition can improve egg quality, humoral immunity, and reproductive performance and regulate the intestinal microbiome and metabolome in breeders. Therefore, multi-enzymes could be used as feed additive to extend breeder service life.

Optimization of exogenous carbohydrases supplemented in broiler diets using in vitro simulated gastrointestinal digestion and response surface methodology

The present study aimed to explore the optimal zymogram of combination of 6 carbohydrases (glucoamylase, pullulanase, maltase, thermostable α-amylase, medium temperature α-amylase, and cold-active α-amylase) supplemented in corn-soybean based diet of broilers aged 1 to 3 wk for the maximum starch digestibility, by using in vitro simulated gastrointestinal digestion and response surface method. The third generation of simulated monogastric animal digestion system was used for in vitro digestion experiment. By using single factor completely random design, the optimal supplement levels of single carbohydras were determined by the reducing sugar release amount and improved dry matter digestibility, which were the parameters representing the starch digestibility of the diet. Additionally, Box-Behnken response surface method was used to predict the optimal combination of 6 carbohydrases. The results showed that the optimistic zymogram of 6 carbohydrases in corn-soybean based diet for broilers aged 1 to 3 wk were 297.39 U/g glucoamylase, 549.72 U/g pullulanase, 3.01 U/g maltase, 1,455.73 U/g thermostable α-amylase, 278.64 U/g medium temperature α-amylase, and 1,985.97 U/g cold-active α-amylase, and the associated reduced sugar release amount and improved dry matter digestibility were 215.98 mg/g, and 6.23%, respectively. Furthermore, we conducted in vitro digestion experiments with diets supplemented with the predicted optimistic zymogram and found that the experimental reduced sugar release amount and improved dry matter digestibility were 219.26 mg/g and 6.31% respectively, whose errors to the predicted optimistic reducing sugar release amount and the improved dry matter digestibility were 1.05% and 1.02%. To sum up, the predicted optimal zymogram of 6 carbohydrases in the present study were capable to improve the starch digestibility in diet for broilers aged 1 to 3 wk, which were represented by increased reduced sugar release amount and improved dry matter digestibility.

A probiotic and mixed-enzymes combination reduces the inflammatory response, faecal shedding and systemic spread of Campylobacter jejuni in broilers

Recent research has questioned the notion that Campylobacter jejuni is a harmless resident of the avian gastrointestinal tract (GIT). The following trial examined the effect of dietary supplementation with a mixture of enzymes and Bacillus-based probiotics on growth performance, C. jejuni colonisation, GIT immune responses, faecal shedding and extra-intestinal spread in broilers. Fifty-eight, Ross 308 d-old broilers were randomly assigned to one of four treatments, giving 14 or 15 birds/pen. Birds were given nutritionally complete, complex, phased diets unsupplemented (two treatments) or supplemented (two treatments) with a multi-enzyme containing 2,000 U/kg xylanase, 200 U/kg amylase and 4,000 U/kg protease, and 75,000 cfu/g of a combination of three strains of Bacillus amyloliquefaciens. One control and one supplemented diet group contained birds orally challenged with 105 cfu C. jejuni strain M1 on d 21 of age. Among challenged birds, the mixed-enzymes and probiotic combination numerically reduced faecal C. jejuni shedding (-98% vs challenged control) three days-post-infection (d.p.i.), and at 7 d.p.i. numerically reduced C. jejuni colonisation of the ileal mucosa (-1000-fold vs control) and totally inhibited systemic spread of C. jejuni to the liver, compared to the control (P<0.05). It suppressed early pro-inflammatory chemokine response seen in the ileum, caecum and caecal tonsil tissues (at 3 d.p.i.) in challenged control birds (-18 to -46-fold; P<0.05) and altered expression of pro-inflammatory (IL-1β, IL-6, IL-17A and IL-17F) and regulatory (IL-10 and TGF-β) cytokines. The data demonstrated inhibition of a sustained pro-inflammatory response to C. jejuni infection and improved intestinal barrier integrity in supplemented birds. This highlighted the importance of looking beyond simple measurements of feed conversion and body weight gain when seeking to understand the effects and mode of action of poultry dietary interventions. Achieving a favourable balance between the gut, immune function, microbiome and nutrition should be the goal for achieving good gastrointestinal health and optimal performance.

A novel consensus bacterial 6-phytase variant totally replaced supplemental inorganic phosphate from one day of age in both male and female broilers

1. This study tested the capacity of a novel consensus bacterial 6-phytase variant (PhyG) to totally replace dietary supplemental inorganic phosphate (Pi) in broilers from one day of age, using a phased dosing strategy for the phytase and a phased reduction in phytate content of the diet. A 2x2 factorial arrangement including two treatments and two genders was used.2. A total of 1,248, one-day-old Ross 308 broilers were assigned to 24 floor pens (52 birds/pen). Two treatments included: 1) a positive control diet (PC) based on mixed grains and oilseed meals, containing inorganic phosphorus (Pi) from monocalcium phosphate (MCP) and 2,000 XU/kg xylanase, and; 2) an inorganic P free (IPF) diet reformulated without Pi, reduced in Ca (-2.0 g/kg) vs. PC and supplemented with PhyG at 3,000 FTU/kg in starter (d 0 to 11, 3.4 g/kg phytate-P (PP)), 2,000 FTU/kg in grower (d 11 to 22, 3.3 g/kg PP), and 1,000 FTU/kg in finisher 1 (d 22 to d 35, 2.9 g/kg PP) and finisher 2 (d 35 to d 42, 2.8 g/kg PP) phase. Each treatment was assigned to 12 pens, with six pens containing males and six containing females. Tibia samples were collected on d 11, 22 and 42 from two birds per pen.3. The IPF treatment maintained or improved ADG, ADFI and FCR compared to PC in all feed phases. IPF increased BW at 42 days of age by 3.97% (P<0.01) and ADG from d 0 to 42 by 4.10% (P<0.01), and reduced corresponding FCR by 1.5 points (P<0.05), respectively, vs. PC. Males exhibited higher BW, ADG and ADFI than females from 11 d of age onwards (P<0.05). An interaction (P<0.05) between treatment and gender was observed for FCR (d 0 to 22, d 0 to 42) and FCRc (body weight corrected FCR, d 0 to 42), whereby IPF treatment reduced (P<0.05) FCR vs. PC in males but not in females. Tibia ash from birds fed IPF was equivalent to PC at 11, 22 and 42 d of age and did not differ between males and females.4.The data demonstrated that the phytase, when applied in a phased dosing-regimen to broiler diets with a graded reduction in phytate-P content, was effective in totally replacing Pi during all growth phases, as determined by performance and tibia ash from both males and females.

Impact of Xylanase and Glucanase on Oligosaccharide Formation, Carbohydrate Fermentation Patterns, and Nutrient Utilization in the Gastrointestinal Tract of Broilers

This study aimed at determining how the degradation of cereal non-starch polysaccharides (NSP) by dietary enzymes during feed digestion can influence nutrient digestibility and NSP fermentability in broilers. Ninety-six one-day-old male broilers were assigned to 4 different treatments: control and enzyme-supplemented wheat-based (WC, WE) or maize-based (MC, ME) treatments. Enzyme supplementation with endo-xylanase and endo-glucanase occurred from day 20 onwards. On day 28, digesta samples were collected. Nutrient digestibility, NSP recovery, oligosaccharide profile, and short-chain fatty acids (SCFA) content were determined. Enzyme supplementation in WE resulted in a higher starch (3%; p = 0.004) and protein (5%; p = 0.002) digestion in the ileum compared to WC. Xylanase activity in WE led to in situ formations of arabinoxylan-oligosaccharides consisting of 5 to 26 pentose units in the ileum. This coincided with decreased arabinose (p = 0.059) and xylose (p = 0.036) amounts in the ceca and higher acetate (p = 0.014) and butyrate (p = 0.044) formation in WE compared to WC. Conversely, complete total tract recovery of arabinoxylan in MC and ME suggested poor maize NSP fermentability. Overall, enzyme action improved nutrient digestibility and arabinoxylan fermentability in the wheat-based diet. The lower response of the maize-based diet to enzyme treatment may be related to the recalcitrance of maize arabinoxylan as well as to the high nutritive value of maize.

A novel consensus bacterial 6-phytase variant completely replaced inorganic phosphate in broiler diets, maintaining growth performance and bone quality: data from two independent trials

Total replacement of dietary inorganic phosphate (Pi) by a novel consensus bacterial 6-phytase variant (PhyG) in phytate-rich diets (>0.3% phytate-P) was investigated in 2 trials using growth performance and bone quality as outcome measures. Both trials utilized a completely randomized design with 5 dietary treatments across 4 phases: starter (0-10 d), grower (10-21 d), finisher 1 (21-35 d), and finisher 2 (35-42 d). Treatments comprised a nutritionally adequate positive control (PC) diet containing monocalcium phosphate and 4 experimental diets (IPF1, IPF2, IPF3, and IPF4), all containing no added Pi and reduced in Ca by 0.2 to 0.3% units vs. PC. IPF1contained PhyG at 1,000 FTU/kg (all phases); IPF2 contained PhyG at 1,000 FTU/kg (all phases) and was additionally reduced in digestible AA, ME, and sodium (-0.2 to -0.4% points, -74 kcal/kg, -0.04% points, respectively, vs. PC); IPF3 contained PhyG at 3,000 FTU/kg in starter, 2,000 FTU/kg in grower, and 1,000 FTU/kg in finisher phases; and IPF4 contained xylanase (2,000 U/kg) and PhyG (2,000 FTU/kg in starter, 1,500 FTU/kg in grower, and 1,000 FTU/kg in finisher phases) and was additionally reduced in ME (-71 kcal/kg vs. PC). Ross 308 broilers were used (trial 1: n = 1,200 mixed sex; 24 birds per pen × 10 replicates; trial 2: n = 1,300 males; 26 birds × 10 replicates). During all phases in both trials, all IPF treatments maintained or improved BW, ADG, ADFI, FCR and BW-corrected FCRc and bone quality parameters vs. PC. vs. PC, treatment IPF3 increased ADG during starter phase (+10.8%) and reduced overall FCRc (-12 points, P < 0.05) in Trial 1, and increased overall ADG (+4.4%), day 35 and day 42 BW (+3.5%, +4.9%), and reduced overall FCRc (-11 points) in Trial 2 (P < 0.05). IPF4 produced equivalent performance to IPF3 (both trials). These are the first data to demonstrate total replacement of Pi by microbial phytase during an entire growth cycle in broiler diets.

Measurement of ileal endogenous energy losses and true ileal digestible energy of cereal grains for broiler chickens

Two experiments were conducted to determine the ileal endogenous energy losses (IEEL) and nitrogen-corrected apparent metabolizable energy (AMEn) and true ileal digestible energy (TIDE) of 4 cereal grains (corn, sorghum, wheat, and barley) for broilers. In experiment 1, a glucose-based purified diet was used to determine the IEEL for correcting the apparent ileal digestible energy (AIDE) values to TIDE. The diet was randomly allocated to 6 replicates (6 birds per replicate) of male broilers and fed from 18 to 21 d after hatch. The jejunal and ileal digesta were collected on day 21. The results showed that glucose absorption continued beyond the jejunum but was complete in the terminal ileum demonstrating that endogenous energy losses can be quantified in the ileal digesta of birds by feeding a glucose-based diet. The IEEL were determined to be 347 ± 29.4 kcal/kg DM intake. In experiment 2, 4 experimental diets with similar inclusion (957 g/kg) of grains were developed to determine the AMEn, AIDE, and TIDE. Titanium dioxide (5.0 g/kg) was added to all diets as an indigestible marker. Each diet was randomly allocated to 6 replicates (8 birds per replicate) and fed from 14 to 21 d after hatch, and the ileal digesta were collected on day 21. The AIDE was corrected to TIDE using the IEEL value determined in experiment 1. The TIDE of corn, sorghum, wheat, and barley were determined to be 3,920, 3,650, 3,138, and 2,885 kcal/kg DM, respectively, and was higher (P < 0.05) than the corresponding AMEn values of 3,439, 3,284, 2,576, and 2,371 kcal/kg DM, respectively. No differences were observed between the AMEn and AIDE. The AMEn:TIDE ratio tended (P = 0.06) to be lower for viscous cereals (wheat and barley) than that for nonviscous cereals (corn and sorghum). The apparent ileal digestibility of DM, nitrogen, and starch was positively correlated (P < 0.001) with TIDE (r = 0.990, 0.703, and 0.705, respectively) and the AMEn (r = 0.873, 0.483, and 0.656, respectively). Further studies are warranted to determine the TIDE of a range of ingredients and to investigate the application of TIDE as a potential available energy system in poultry feed formulations.

Effects of a combination of xylanase, amylase and protease, and probiotics on major nutrients including amino acids and non-starch polysaccharides utilization in broilers fed different level of fibers

This study evaluated the effects of a combination of xylanase, amylase, and protease (XAP), with probiotics (3 Bacillus spp.) supplementation on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients in Cobb 500 broilers from 0 to 21 d. A completely randomized 2 × 4 factorial design (2 levels of fiber; 4 types of supplements) with 8 replicate cages (6 birds/cage) was used. Each low and high-fiber diet contained 500 FTU/kg Buttiauxella sp. phytase and was supplemented with: (a) none (control), (b) XAP (2,000 U xylanase + 200 U amylase + 4,000 U protease/kg diet), (c) probiotics (75,000 CFU/g of Bacillus spp.), or (d) XAP + probiotics. High fiber decreased (P < 0.05) nitrogen-corrected apparent metabolizable energy (AMEn), AID of all amino acids (AA), AID and ATTD of dry matter (DM), crude protein (CP), starch, and gross energy (GE). High fiber increased (P < 0.01) the flow of total non-starch polysaccharides (NSP) in both ileum and total tract. The XAP + probiotics increased (P < 0.01) AMEn as well as AID and ATTD of DM, CP, GE, starch, while alone, XAP yielded similar improvement except for DM compared with control. The supplemental XAP alone improved (P < 0.01) the digestibility of most of the AAs compared with control. Moreover, XAP + probiotics increased (P < 0.05) AID of all AA except arginine and serine compared with control. A fiber × supplements interaction (P < 0.05) was found for AID of histidine and threonine, and their digestibility in high-fiber diet was improved to a level comparable to low-fiber diet by XAP + probiotics. The flow of NSP in XAP group was 5 to 6% lower than in control while NSP flow in XAP + probiotic group was further 4% lower than that of XAP group (P < 0.01). The results infer that the combination of XAP and probiotics can effectively optimize the nutrient digestibility in broilers fed both low and high-fiber diets.

Comparative effects of two multi-enzyme combinations and a Bacillus probiotic on growth performance, digestibility of energy and nutrients, disappearance of non-starch polysaccharides, and gut microflora in broiler chickens

The efficacy of two exogenous enzyme combinations and a multi-strain Bacillus probiotic (DFM) on the growth performance, nutrient digestibility, disappearance of non-starch polysaccharides (NSP) and gut microbial composition was investigated in broilers. One-day old Ross 308 chicks were assigned to 36 pens with 22 birds/pen and 6 pens/treatment (Experiment 1) or 36 cages with 8 birds/cage and 6 cages/treatment (Experiment 2). Treatment additives were added to nutritionally complete corn/soy based starter (d 1 to 21) and finisher (d 22 to 42) diets. Treatments included 1) a control diet containing 500 FTU/kg phytase (CTL), 2) CTL + xylanase (2,000 U/kg) and amylase (200 U/kg; XA), 3) CTL+XA + protease (4000 U/g; XAP), 4) CTL+DFM (150,000 cfu/g of 3 strains of Bacillus spp), 5) CTL+DFM+XA, and 6) CTL+DFM+XAP. Supplementation with DFM increased BW, BWG, and FI compared with the CTL (P < 0.05); XAP, but not XA, resulted in increased final BW, BWG and FI compared to the control (P < 0.05). XA and XAP improved apparent ileal digestibility (AID) of starch and fat on d 22 to 42 with XAP improving AME_n (by ∼82 kcal) compared with CTL birds (P < 0.01). DFM+XAP improved apparent ileal digestible energy (AIDE), AID of fat and starch on d 22 to 42, and additionally had a greater than additive effect on AIDE and AME_n. Supplementation with DFM+XAP reduced the ileal and total tract flow of insoluble arabinose and additionally total tract flow of soluble and insoluble xylose and total galactose (P < 0.05); similar effects of XA+DFM were not seen or were lower in magnitude, suggesting that the protease component plays an important role in increasing the availability of NSP for hydrolysis. Supplementation with DFM alone did not affect gut bacterial populations, but XA and XAP reduced numbers of Campylobacter species (by > 2.5 log cfu/g; P < 0.001) and Bacteroides (P < 0.02) in the cecum compared with CTL birds.

Exogenous dietary enzyme formulations improve growth performance of broiler chickens fed a low-energy diet targeting the intestinal nutrient transporter genes

Diminishing the cost of broiler chicken diet is a critical issue in the poultry industry. Numerous studies were performed to achieve this pivotal objective by diet supplementation with alternative feed additives. In the current study, low-energy broiler rations were supplemented with different commercial multienzyme formulations to minimize the cost, and increase the digestibility and absorption of the digested macronutrients. Cobb Avian 48 broiler chicks (mixed sex, 1-d-old, n = 3120) were randomly allocated into six groups, and each group was subdivided into four replicates (130 birds per replicate). The birds were randomly allocated into a control group fed basal diet (CB); control group fed low-energy diet (CL); and birds fed low-energy diets supplemented with different enzyme formulations. The enzyme formulations used were Xylam 500® (CLX group), Hemicell® (CLH group), Avizyme® (CLA group), and Megazyme® (CLM group,) following the doses recommended by the manufacturers. The growth performance of CLA and CLH group birds was significantly improved when compared with CL. In comparison with CB, Avizyme® significantly (p < 0.001) increased the intestinal PEPT1, GLUT2, ACC, and IL-2 expression; PEPT1 facilitates the absorption of micronutrients. In conclusion, exogenous multienzyme complexes may be included in the low-energy diet to enhance the performance of broiler chickens (Avizyme® ˃ Hemicell® ˃ Megazyme®), and reduce the diet cost by up-regulating the expression of intestinal nutrient transporter genes, and improving the immunity and serum biochemical parameters of broiler chickens.

Effect of exogenous xylanase, amylase, and protease as single or combined activities on nutrient digestibility and growth performance of broilers fed corn/soy diets

Two trials (a 42-d performance and a 21-d cohort digestibility) were conducted to evaluate the performance and nutrient digestibility of broilers fed corn diets supplemented with exogenous xylanase, amylase, and protease as single or combined activities. A nutritionally adequate, positive control (PC) diet was formulated. The negative control (NC) diet was formulated to be lower in metabolizable energy (∼86 kcal/kg diet) and digestible amino acids (1 to 2%) compared to PC. The other 4 treatments were based on the NC and they were either supplemented with xylanase (X), amylase (A), protease (P), or a combination of X, A, and P (XAP; to provide 2,000 U of X, 200 U of A, and 4,000 U of P/kg diet). All diets were marginal in AvP and Ca and contained a background of phytase (1,000 FTU/kg). In each trial, male broiler (Ross 308) chicks were allocated to the 5 treatments (10 replicates of 20 birds/pen and 9 replicates of 8 birds/cage for the performance and digestibility trials, respectively). In the digestibility trial, ileal digesta was collected on d21 for the determination of nutrient utilization. Data were subjected to one-way ANOVA and means were separated by Tukey's HSD test. Only the XAP improved (P < 0.05) AMEn compared to NC. X, A or XAP improved (P < 0.05) N digestibility and apparent ileal digestible energy (AIDE). Both P and XAP improved N retention. The relative improvement in energy digestibility due to enzyme supplementation was greater at the ileal level than that measured in the excreta. The measured changes on AIDE due to supplemental enzymes were much higher than the sum of calculated contributions from starch, fat, and protein. Supplementation of all enzymes reduced (P < 0.05) ileal flow of soluble rhamnose and mannose relative to NC. In the performance trial, both X and XAP improved (P < 0.05) weight gain (WG) and only XAP improved (P < 0.05) FCR compared to NC during the starter phase (1-21d). Over the entire period (1–42d), WG and FI were not influenced (P > 0.05) by dietary treatments. Both X and XAP had lower (P < 0.05) FCR compared to NC (1.540 and 1.509 vs 1.567, respectively). However, birds fed diet supplemented with XAP had an improved (P < 0.05) FCR compared to birds fed single activities and had similar (P > 0.05) FCR compared to PC. In conclusion, these results suggest a synergistic effect between X, A and P on broiler performance and nutrient digestibility. In the current study, AIDE measurements appeared to overestimate the enzyme response. Calculation of the energy contribution by supplemental enzymes using the improvements in the digestibility of the undigested fraction of starch, fat and protein may be a more accurate measurement for the enzyme response than the absolute response in AIDE.

Effects of exogenous proteases without or with carbohydrases on nutrient digestibility and disappearance of non-starch polysaccharides in broiler chickens

The objective of the current study was to evaluate the effect of a subtilisin protease, without or with inclusion of carbohydrases, on digestibility and retention of energy and protein, as well as the solubilization and disappearance of non-starch polysaccharides (NSP) from corn-soybean meal based diets fed to broiler chickens. Two hundred eighty-eight Ross 308 male broiler chickens were used for the experiment. On d 14, the birds were weighed and allocated to 6 treatments and 8 replicates per treatment with 6 birds per replicate. Treatments were: 1) corn-soybean meal based control diet; 2) control diet plus supplemental protease at 5,000 (P5000) protease units (PU)/kg); 3) control plus 10,000 PU/kg protease (P10000); or control plus an enzyme combination containing xylanase, amylase, and protease (XAP) added to achieve protease activity of: 4) 2,500 PU/kg (XAP2500); 5) 5,000 PU/kg (XAP5000); or 6) 10,000 PU/kg (XAP10000). The enzymes in XAP were combined at fixed ratios of 10:1:25 of xylanase:amylase:protease. Data were analyzed by ANOVA and specific orthogonal contrasts between treatments were performed. Addition of xylanase and amylase increased (P < 0.05) the ileal digestibility of protein by 4.2% and 2.1% at XAP5000 and XAP10000, respectively (relative to P5000 and P10000, respectively), exhibiting a plateau after the XAP5000 dose. Increment (P < 0.05) in AME due to protease was evident, particularly in P10000. At the ileal level, XAP reduced (P < 0.05) the flow of insoluble xylose and arabinose, which indicates an increase in the solubilization of arabinoxylan polymers in the small intestine. Protease on its own reduced (P < 0.05) the flow of insoluble arabinose but did not affect the flow of insoluble xylose. XAP reduced (P < 0.05) the pre-cecal flow of insoluble and total glucose and galactose. It was concluded that whereas protease by itself improved nutrient utilization and increased solubilization of NSP components, at the lower dose, a combination of xylanase, amylase, and protease produced effects greater than those of protease alone.