A mono-component microbial protease improves performance, net energy, and digestibility of amino acids and starch, and upregulates jejunal expression of genes responsible for peptide transport in broilers fed corn/wheat-based diets supplemented with xylanase and phytase

Metabolizable energy and digestible nutrient values of protease-supplemented field pea for broiler chicken

A study was conducted to determine the effects of protease supplementation of field pea (in comparison with soybean meal; SBM) for broilers on apparent metabolizable energy (AMEn) and standardized ileal digestibility (SID) of amino acids (AA). One hundred and forty broiler chicks were divided into 35 groups of 4 birds/group and fed 5 diets in a completely randomized design (7 groups/diet) from 14 to 21 d of age. The diets were cornstarch-based containing SBM or field pea as the sole protein source without or with protease (ProSparity 250TM; CBS Bio Platforms, Calgary, AB, Canada) in 2 × 2 factorial arrangement, and N-free diet. Protease was added to diets to supply 6,250 U/kg. Digestibility of AA and N retention for feedstuffs were determined by the direct method, whereas digestibility and retention of energy for feedstuffs were determined by the difference from the N-free diet. On as fed basis, SBM and field pea contained 90.0 and 88.9 dry matter, 46.6 and 20.2 % crude protein, 2.88 and 1.47 % Lys, and 14.3 and 14.7 % non-starch polysaccharides, respectively. On as fed basis, the AMEn value for field pea was lower (P < 0.05) than that of SBM (2,006 vs. 2,414 kcal/kg). Also, the SID values of most indispensable AA in field pea were lower (P < 0.05) than those in SBM. Feedstuff (field pea vs. SBM) and protease did not interact on AMEn and SID of AA values. The supplemental protease increased (P < 0.05) AMEn values of the SBM and field by an average of 187 kcal/kg but decreased (P < 0.05) the SID values of all indispensable AA (except His) for the SBM and field, by an average of 2.7 percentage points. Results indicate that the protease product used in the current study marginally reduced the SID of AA for both SBM and field pea. However, the protease product can be beneficially included in diets based on SBM or field pea for broilers to enhance their AMEn values. The response to the protease on the AMEn was consistent regardless of the protein source in the diet, implying that the protease used in this study has similar positive impact on energy availability in both field pea and SBM.

Effects of dietary protease supplementation on in vitro soybean meal protein, dry matter digestibility, and productive performance in starter-to-finisher pigs

Background and Aim

Pig industries are currently facing a crisis in terms of protein and energy costs. Proteases were used to increase protein digestibility and metabolizable energy (ME) in diets. This study evaluated the effects of protease supplementation on in vitro protein digestibility and productive performance in starter-to-finisher pigs.

Materials and Methods

A total of 691 starter pigs were randomly allocated into three dietary treatments using a randomized complete block design. Diets were provided in three phases according to body weight (BW): Starter, grower, and finisher phases. Each phase was fed for 30, 60, and 24 days of treatment diets as T1: basal diet and T2 and T3: the basal diet supplemented with 240 ppm protease reduced by 50 kcal/kg ME plus 1% crude protein (CP) and by 100 kcal/kg ME plus 2% CP, respectively. Protease and in vitro protein digestibility were measured. BW and feed intake were recorded to calculate the average daily gain (ADG), average daily feed intake (ADFI), feed-to-gain (F:G), and gain-to-feed (G:F) ratios.

Results

There were no significant differences (p > 0.05) in the percentage of in vitro protein digestibility between the groups with and without protease supplementation. In the finisher phase, T2 had lower (p < 0.05) ADFI and F:G than T1 and T3. Overall, T3 had lower (p < 0.05) ADG, ADFI, and F:G than T1 and T2.

Conclusion

Protease supplementation significantly affects protein digestibility. Supplementing basal diets with 240 ppm protease reduced ME by 50 kcal/kg and CP by 1% without affecting ADG, ADFI, F:G, and G:F ratios for starter-to-finisher pigs.

Comparative effects of proteases on performance, carcass traits and gut structure of broilers fed diets reduced in protein and amino acids

This study aimed to evaluate the effect of supplementing different protease enzymes on growth performance, intestinal morphology, and selected carcass traits in broilers fed diets reduced 3.5% in crude protein (CP) and amino acids (AA). One thousand one-day-old Ross 308 broilers (41 g) were assigned to five dietary treatments with ten replicates of 20 birds each: a positive control (PC) diet formulated to meet Ross 308 AA requirements, a negative control (NC) diet reformulated to provide 3.5% lower CP and AA compared to PC, NC supplemented with a multi-protease (PR1) solution, containing 3 different coated proteases produced from Aspergillus niger, Bacillus subtilis and Bacillus licheniformis, NC supplemented with a serine protease (PR2) produced from Bacillus licheniformis, and NC supplemented with an alkaline protease (PR3) produced from Bacillus licheniformis. At slaughter, 40 birds per treatment were used to assess the effect of the different treatments on carcass traits. At 32 days, samples of the duodenum, jejunum, and ileum of 10 birds per treatment were collected for intestinal morphology evaluation. Birds fed PC and NC supplemented with multi-protease exhibited better (p < 0.05) feed efficiency compared to NC and NC supplemented with all the other protease enzymes. Multi-protease supplementation was linked to the highest (p < 0.05) carcass weight and yield. There were significant differences (p < 0.05) between treatments in all gut segments, with PC, PR1, PR2, and PR3 exhibiting longer villi height (VH) compared to NC. This study demonstrates that 3.5% reduction of CP and AA negatively affected for the overall period feed efficiency, carcass yield, and intestinal morphology. The supplementation of the multi-protease restored feed efficiency and improved carcass yield.

Rosa D, Teixeira L, B. Sorbara JO, J. Cowieson A, Faruk MU. Effects of dietary digestible amino acids and a novel exogenous sfericase protease on growth performance of broilers

Two experiments (Exp.) were conducted to evaluate the effects of a novel exogenous sfericase protease on growth performance and ileal digestibility of broiler chickens until day 35 of age. In Exp. 1, 1350 one-day-old male chicks (Cobb 500) were allocated in 54 floor pens and fed one of the three dietary treatments, with 18 replicates of 25 birds each in a completely randomized design. Diets consisted of positive control [PC; commercially relevant ME and balanced amino acids (AA)]; negative control (NC; with reduction of 6% dig. Lys and proportional reductions for adjacent AA compared to the PC), and NC supplemented with sfericase protease [30,000 New Feed Protease units (NFP)/kg]. On day 35, ileal digesta was collected to determine apparent ileal digestibility of dry matter and nitrogen (N). In Exp. 2, 1620 one-day-old male chicks (Cobb 500) were allocated in 54 floor pens having three treatments and 18 replicates of 30 birds each in a completely randomized design from day 1-35. Broilers were fed a control basal diet (Control); Control supplemented with sfericase at 30,000 NFP/kg and at 60,000 NFP/kg. In Exp. 1, from day 1-35, body weight gain (BW gain) and feed conversion ratio (FCR) of broilers improved 3.4 and 2.5% when diets were supplemented with sfericase, respectively, whereas the digestibility of N increased by 2.7% compared to the NC. In Exp. 2, diets with usual protein and AA levels and supplemented with 30,000 NFP/kg had 2.3 and 1.75% improved BW gain and FCR from day 1-35, respectively. When diets were supplemented with 60,000 NFP/kg, BW gain and FCR were enhanced by 3.9 and 3.2%, respectively compared to the Control. In conclusion, these results demonstrate that the novel sfericase protease could be successfully used in corn-soy diets with protein and AA reductions or in feed formulations with usual digestible AA levels to enhance growth performance of broilers.

Prediction of net energy of feeds for broiler chickens

Net energy (NE) enables the prediction of more accurate feed energy values by taking into account the heat increment which is approximately 25% of apparent metabolizable energy (AME) in poultry. Nevertheless, application of NE in poultry industry has not been practiced widely. To predict the NE values of broiler diets, 23 diets were prepared by using 13 major ingredients (wheat, corn, paddy rice, broken rice, cassava pellets, full-fat soybean, soybean meal, canola meal, animal protein, rice bran, wheat bran, palm kernel meal and palm kernel oil). The diets were formulated in order to meet the birds' requirements and get a wide range of chemical compositions (on DM basis; 33.6% to 55.3% for starch; 20.8% to 28.4% for CP, 2.7% to 10.6% for ether extract [EE] and 7.0% to 17.2% for NDF), with low correlations between these nutrients and low correlations between the inclusion levels of ingredients allowing for the calculation of robust prediction equations of energy values of diets or ingredients. These diets were fed to Ross 308 broilers raised in 12 open-circuit respiratory chambers from 18 to 23 d of age (4 birds per cage) and growth performance, diet AME content and heat production were measured, and dietary NE values were calculated. The trial was conducted on a weekly basis with 12 diets measured each week (1 per chamber), 1 of the 23 diets (reference diet) being measured each week. Each diet was tested at least 8 times. In total, 235 energy balance data values were available for the final calculations. Growth performance, AME (15.3 MJ/kg DM on average) and AME/GE (79.4% on average) values were as expected. The NE/AME value averaged 76.6% and was negatively influenced by CP and NDF and positively by EE in connection with efficiencies of AME provided by CP, EE and starch for NE of 73%, 87% and 81%, respectively. The best prediction equation was: NE = (0.815 × AME) - (0.026 × CP) + (0.020 × EE) - (0.024 × NDF) with NE and AME as MJ/kg DM, and CP, EE and NDF as % of DM. The NE prediction equations from this study agree with other recently reported equations in poultry and are suitable for both ingredients and complete feeds.

Effects of dietary multienzymes on the growth performance, digestive enzyme activity, nutrient digestibility, excreta noxious gas emission, and nutrient transporter gene expression in white feather broilers

Adding multienzymes to poultry feed rations is recognized as a nutritional strategy aimed at improving poultry performance and health status. Nonetheless, some literatures present an ongoing debate about the extent of multienzymes beneficial impact on poultry growth performance. This study aimed to explore the impacts of dietary multienzyme supplementation on broilers, focusing specifically on growth performance, carcass characteristics, apparent nutrient digestibility, excreta noxious gas emission, and intestinal nutrient transporter gene expression. A total of 3,200 broilers were randomly assigned to five groups (eight replicates per treatment group) and treated with the following: normal control (CON), CON + 100 g/t multienzyme (ME100), CON + 150 g/t multienzyme (ME150), CON + 200 g/t multienzyme (ME200), and CON + 250 g/t multienzyme (ME250). Supplementing with multienzymes significantly influenced the feed conversion rate (linear, P = 0.007; quadratic, P = 0.024) and the European broiler index (linear, P = 0.004; quadratic, P = 0.016) in broilers. Dietary multienzymes significantly influenced apparent metabolizable energy (quadratic, P = 0.015) and neutral detergent fiber (quadratic, P < 0.001). Moreover, multienzyme supplementation in the diet also decreased the emission of ammonia (linear, P = 0.001; quadratic, P = 0.006) and hydrogen sulfide (quadratic, P = 0.006) in the excreta. In addition, dietary multi-enzyme notably elevated (P < 0.05) the mRNA expression of nutrient transporter genes, including peptide transporter 1 (PePT1), Na-dependent neutral amino acid transporter (B0AT), glucose transporter 2 (GLUT2), and fatty acid binding protein1 (FABP1). These findings suggest that dietary supplementation with multienzymes can improve the efficiency of feed utilization, and the digestion and absorption of nutrients and reduce excreta gas emission. Furthermore, this study provides a theoretical basis for advancing the use of multienzymes in broiler production.

Growth performance and nutrient digestibility of broiler chickens as affected by a novel protease

Two experiments evaluated the addition of an exogenous sfericase protease in broiler diets. Experiments were run (Exp1 and Exp2) with 1,848 and 2,100 one-day-old male chicks being allocated into 84 floor pens with 14 replicates of 22 and 25 birds each, respectively. The studies were conducted in completely randomized designs. In Exp1, Standard diets were formulated with energy and AA at marginally lower levels than usual by the Brazilian integration such that broilers were expected to grow at comparatively reduced rates to the industry whereas in Exp2, the Standard diets were formulated using energy and AA as usual by the Brazilian integrations such that broilers were expected to grow comparable to industry rates. Standard diets had ideally balanced amino acids (AA). Matrix diets, in contrast, had reductions of 6% digestible lysine and of 20 kcal AME/kg compared to the Standard. Matrix diets were supplemented with an sfericase protease at 0, 10,000, and 30,000 New Feed Protease units (NFP)/kg. Outcomes showed no interaction between diet and protease in any of the experiments. However, broilers fed Standard diets had higher cumulative body weight gain (BWG) to 35 and 42 d when compared to Matrix fed birds whereas FCR were worse for birds fed the Matrix diets at 35 d in EXP1 and at 35 and 42 d in EXP2. Improvements in FCR were observed when the sfericase protease was added throughout all ages in EXP1 with a beneficial trend (P&lt;0.067) observed in the cumulative FCR at 42 d in EXP2. The ileal digestible crude protein (IDCP) was significantly higher for birds fed Standard feeds in EXP1 with no other differences in digestibility found in any of the experiments. Protease addition led to improvements in ileal digestibility of dry matter (IDM) and IDCP (P &lt; 0.05) compared to no protease addition in EXP1 as well as in ileal digestibility of energy (IDE) when 30,000 protease units were added. The present report demonstrates that the novel sfericase protease was successful in compensate broiler performance when reductions of 6% digestible Lys and 20 kcal/kg AME were imposed. This compensation, however, seemed more notable when birds were fed diets formulated to support moderate rather than maximum growth and having animal protein in the feed formula.

Protease supplementation reduced the heat increment of feed and improved energy and nitrogen partitioning in broilers fed maize-based diets with supplemental phytase and xylanase

An experiment was conducted to explore the effects of digestible amino acid (dAA) concentrations and supplemental protease on live performance and energy partitioning in broilers. Ross 308 male broilers (n = 288) were distributed into 24 floor pens and offered 1 of 4 dietary treatments with 6 replicates from 1 to 35 d of age. Dietary treatments consisted of a 2 × 2 factorial arrangement with dAA concentrations (standard and reduced [34 g/kg below standard]) and supplemental protease (without or with) as the main factors. At 1, 15, 28, and 35 d of age, feed and broilers were weighed to determine live performance. From 20 to 23 d of age, a total of 32 birds (2 birds/chamber, 4 replicates) were placed in closed-calorimeter chambers to determine respiratory exchange (heat production, HP), apparent metabolisable energy (AME), retained energy (RE), and net energy (NE). From 29 to 35 d of age, supplemental protease in the reduced-dAA diet decreased broiler feed conversion ratio (FCR) by 5.6 points, whereas protease supplementation in the standard-dAA diet increased FCR by 5.8 points. The indirect calorimetry assay revealed that supplemental protease decreased (P < 0.05) the heat increment of feed (HIF) by 0.22 MJ/kg. Also, from 20 to 23 d of age, broilers offered the reduced-dAA diet with supplemental protease had a higher daily body weight gain (BWG) (+10.4%), N intake (+7.1%), and N retention (+8.2%) than those offered the standard-dAA with supplemental protease. Broilers offered the reduced-dAA without supplemental protease exhibited a 3.6% higher AME-to-crude protein (CP) ratio than those offered other treatments. Protease supplementation in the standard- and reduced-dAA diets resulted in 2.7% and 5.6% lower AME intake-to-N retention ratios, respectively, compared with the unsupplemented controls. Reduced-dAA increased (P < 0.05) AME intake (+4.8%), RE (+9.8%), NE intake (+5.8%), NE intake-to-CP ratio (+3.0%), and RE fat-to-RE ratio (+8.6%). Protease supplementation increased (P < 0.05) respiratory quotient (+1.2%) and N retention-to-N intake ratio (+2.2%), NE-to-AME ratio (+1.9%), and reduced HP (−3.6%), heat increment (−7.4%), and NE intake-to-N retention (−2.5%). In conclusion, protease positively affected FCR and energy partitioning in broilers; responses were most apparent in diets with reduced-dAA concentrations.

Varying apparent metabolizable energy concentrations and protease supplementation affected broiler performance and jejunal and ileal nutrient digestibility from 1 to 35 d of age

An experiment was conducted to evaluate the effects of varying AME concentrations and protease supplementation on broiler performance and jejunal and ileal nutrient digestibility from 1 to 35 d of age. Ross × Ross 308 male broilers (n = 1,008) were equally distributed into 48 floor pens and offered 1 of 6 dietary treatments (8 replicate pens/treatment). Dietary treatments consisted of a factorial arrangement with AME concentration (low-, moderate-, or high-AME) and supplemental protease (without or with) as the main factors. Birds and feed were weighed on 1, 15, 29, and 35 d of age to determine body BW, BW gain (BWG), feed intake (FI) and feed conversion ratio (FCR). At 15 and 29 d of age, jejunal and ileal digesta contents were collected to determine nutrient digestibility. From 1 to 15 d of age, broilers offered moderate-AME diets (P < 0.05) had 6.7, 7.1, 4.8% higher BW, BWG, FI, respectively, and a 2.1% lower FCR compared with those offered low-AME diets. Likewise, protease increased (P < 0.05) BW and BWG by 4.3 and 4.7%, respectively, and decreased (P < 0.05) FCR by 3.4%, compared with those offered the diets without protease. From 1 to 29 d of age, broilers offered high-AME diets had 2.9% lower (P < 0.05) FCR compared with those offered low-AME diets. Protease increased (P < 0.05) BW, BWG, and FI by 3.1, 3.2, and 4.2%, respectively, compared with the unsupplemented diets. From 1 to 35 d of age, broilers receiving high-AME diets had 2.9% lower (P < 0.05) FCR compared with those offered low-AME diets. Protease increased (P < 0.05) FCR by 1.0% compared with those offered unsupplemented diets. Jejunal (15 and 29 d of age) and ileal (29 d of age) starch digestibility and jejunal nitrogen digestibility (29 d of age) were lower (P < 0.05) in broilers offered high-AME diets compared with those offered low-AME diets. Both AME concentration and supplemental protease independently affected broiler performance, with responses being most apparent during early growth phases whereas digestibility measures were mainly influenced by AME concentration.

Air-classified faba bean protein fraction as a substitute to soybean meal in pelleted and extruded broiler diets

1. The hypothesis that air-classified faba bean protein fraction (FBP) can replace soybean meal (SBM) in pelleted or extruded broiler diets without adverse effect on performance or nutrient digestibility was tested.2. At 17 d of age, male broilers were randomly distriibuted among four dietary treatments consisting of either SBM or FBP (main dietary protein source) and pelleting or extrusion as processing methods. Treatments had 10 replicate pens containing five birds each.3. Compared to SBM, birds fed FBP had significantly lower feed intake, less weight gain and had poorer feed conversion.4. Pellet durability was high (above 92%) for all diets. In pelleted diets, FBP was harder than SBM whereas extruded diets had similar hardness. Pelleting increased water stability compared to extrusion. FBP diets were more water stable than the SBM diets.5. Gizzard content weight was 2.2-fold higher (P = 0.002) for birds given FBP compared to those fed SBM. The weight of the jejunum and ileum with contents was 1.4-fold lower for the FBP diets, and this effect was larger (P < 0.05) for the extruded FBP diet.6. Birds fed FBP diets had significantly higher nitrogen digestibility in the lower jejunum and ileum compared to those given SBM diets, while the starch digestibility coefficient was above 0.980 in all treatments.7. The high nutrient digestibility of FBP diets indicates that the poor performance of the FBP group was due to lower feed intake which was not explained by the differences in pellet durability or hardness. The reduced palatability of the FBP and the longer retention of the FBP diets in the upper gut are more likely to have depressed feed intake.

Standardized ileal digestibility of amino acids of protein sources associated with exogenous enzymes for broilers

Objective

Two experiments were conducted to evaluate the effect of enzyme complex (EC) on the standardized ileal digestibility (SID) of amino acids (AA) in corn gluten meal (60%) (CGM), soy protein concentrate (SPC), dried bovine plasma (DBP) and poultry offal meal (POM). Experiments I and II were conducted with broilers in the pre-starter (1 to 7 days of age) and starter (1 to 21 days of age) phases, respectively.

Methods

The treatments consisted of a protein-free diet (PFD) containing feedstuffs either supplemented with EC (xylanase, amylase, and protease) or not. In Experiment I, a total of 360 one-day-old male Cobb-500® broiler chicks were randomly housed in 45 pens, resulting in five replicates with eight birds each, totalizing eight treatments and one PFD group. In Experiment II a total of 270 one-day-old male Cobb-500® broiler chicks were randomly housed in 45 pens, resulting in five replicates with six birds each, totalizing eight treatments and one PFD group. The PFD groups were used to assess the endogenous AA losses. The birds were slaughtered to collect the ileal content.

Results

In the pre-starter phase, the SID of arginine, branched chain-aminoacids, glycine, serine, aspartate, and glutamic acid increased with EC addition. The EC improved the SID of arginine and glutamic acid of CGM; the SID of valine and cystine of SPC; the SID of leucine, glycine, and aspartate of POM and the SID of isoleucine of DBP. In the starter phase, the SID of isoleucine, phenylalanine and glycine increased in EC-supplemented diets. The EC improved the SID of isoleucine of DBP; the SID of phenylalanine of CGM and POM. The SID of AA of SPC was not influenced by the EC.

Conclusion

The addition of an enzyme complex to broiler pre-starter and starter diets is efficient in increasing the SID of AA on SPC, POM and DBP.

Effects of protease supplementation and diet type on jejunal and ileal digestibility and total tract metabolisability of nitrogen, starch, and energy in broilers

1. A study was conducted to assess the effects of supplemental protease (0 or 15,000 units/kg) and diet type (maize- or wheat-based) on apparent jejunal and ileal digestibility and apparent total tract metabolisability of nutrients in Cobb 500 mixed-sex broilers from 6 to 31 d of age.2. Birds were randomly distributed into 56 metabolism cages (6 birds/cage; 14 replicates/treatment). At 22 d of age, jejunal and ileal digesta contents were collected and pooled from 4 birds/cage to determine apparent digestibility coefficients (DC) and digestible energy (DE). Feed intake was measured, and total excreta were collected from 8 to 11 and 18 to 21 d of age to determine apparent metabolisable energy (AME) and total tract nitrogen and starch metabolisability coefficients.3. Broilers offered the maize-based diet with protease had greater (P < 0.05) jejunal nitrogen DC, starch DC, and DE (8.2, 6.5, and 14.9%, respectively) and ileal nitrogen DC and DE (5.1 and 6.8%, respectively) than those offered the maize-based diet without protease. Ileal starch DC was increased (P < 0.05) by 1.1% with protease supplementation.4. Broilers offered maize-based diets had greater (P < 0.05) nitrogen (7.3%) and starch (0.6%) metabolisability coefficients and AME (4.7%) from 8 to 11 d of age, and nitrogen (4.3%) metabolisability coefficients and AME (2.0%) from 18 to 21 d of age compared with those offered wheat-based diets.5. Thus, protease supplementation and diet type can affect digestive dynamics and nutrient utilisation in broilers.

Effects of potato peels inclusion with exogenous enzymes in broiler diet on growth performance, nutrients digestibility and carcass characteristics

The purpose of the research was to investigate the effects of including potato peels (PP) in broilers diet with exogenous enzymes supplementation on feed intake (FI), body weight gain (BWG), nutrient digestibility and carcass parameters. For this purpose, five iso-caloric and iso-nitrogenous rations were formulated with different levels of PP (0, 5, 10, 15 and 20%). Experimental diets were supplemented with a blend of exogenous enzymes (Xylanase, Mannanase, Protease, Cellulase). A total of four hundred male broiler chicks (day old) of 38 ± 3 gram were randomly distributed into 5 experimental groups in such a way that each group had 8 replicates and each replicate had 10 birds. Results revealed that the inclusion of PP @ 5% with exogenous enzymes had similar FI, BWG and nutrients digestibility with control. However, the inclusion of P @ of 10, 15, and 20% with exogenous enzymes in the broiler diet adversely affected the BWG, feed conversion ratio and nutrient digestibility (p < 0.05). Results of carcass parameters were not affected (p > 0.05) by dietary treatments. Based on findings, it is concluded that 5% addition of PP with exogenous enzymes could be practiced in broiler diet without any adverse effect on the performance of commercial broilers.

Protease supplementation in maize-based diet influenced net energy and nutrient digestibility in broilers

This experiment evaluated the effects of supplemental protease in maize-based diets formulated with reduced density of digestible amino acids (dAA) on net energy (NE) utilisation and nutrient digestibility in broilers. A total of 312, one-day-old, male broilers (Ross 308) were randomly distributed into 24 floor pens and fed one of three treatments, with eight pen replicates per treatment throughout the starter (1 to 14 d of age) and grower (15 to 28 d of age) phases. Dietary treatments consisted of a positive control (PC) reference diet, a negative control diet (NC; dAA density 60 g/kg less than PC diet), and a NC diet with supplemental protease (200 mg/kg). All diets contained supplemental phytase (200 mg/kg) and xylanase (200 mg/kg). The reduction in dAA density between the PC and NC did not affect (P>0.05) NE, but protease supplementation in the NC diet increased (P<0.05) NE by 0.27 MJ/kg, compared with those receiving the NC diet without protease. The reduction in dAA for broilers fed the NC and PC diets did not (P>0.05) affect nitrogen, starch, or DE in the jejunum or ileum. Likewise, no differences (P>0.05) in jejunal (nitrogen, starch, and DE) and ileal (starch and DE) digestibility values were observed between those offered the NC diets without or with protease, but a small difference (P<0.05) in ileal nitrogen digestibility was observed.

Different enzymatic associations in diets of broiler chickens formulated with corn dried at various temperatures

The effect of supplementation of different enzymatic associations in the feed of broiler chickens formulated with corn dried at 80°C or 110°C on growth performance and carcass yield was evaluated. In addition, the influence of the different enzymatic associations on the cecal microbiota was studied. One-day-old male broiler chicks (1,320) were distributed in a completely randomized design in a 2 × 5 factorial arrangement (6 replicates; 22 birds/replicate). The treatments were 2 corn drying temperatures (80°C and 110°C) and 5 diets. The diets consisted of a positive control (PC), a negative control (NC) with a reduction of 100 kcal/kg of apparent metabolizable energy, and 3 enzyme combinations added to the NC diet: amylase, amylase + xylanase, and amylase + xylanase + protease. The feed conversion ratio (FCR) from 1 to 7 d of chickens fed diets formulated with corn dried at 80°C was better (P = 0.045) than that of chickens fed diets dried at 110°C. Regardless of the enzymatic association, the supplementation improved body weight gain (P = 0.01) of the NC group to the same level as the PC group. The FCR of the NC was similar to that of the PC only when the 3 enzymes were included from 1 to 21 d (P = 0.001) and regardless of the enzymatic association for the period from 1 to 42 d (P = 0.007). Regarding cecal microbiota, the alpha diversity was similar among the groups (P > 0.05). The beta-diversity analysis showed that the microbiota of the birds receiving the combination of the 3 enzymes was similar to that of birds fed the PC diet (P = 0.18; R = 0.074), with a similar effect observed for the predicted metabolic functions (Linear discriminant analysis effect size). In conclusion, chickens fed diets formulated with corn dried at 80°C had better FCR during the prestarter phase. The enzymatic supplementation improved the FCR of the birds, which may partially be explained by the modulation of the cecal microbiota.

Amino acid digestibility coefficient values of animal protein meals with dietary protease for broiler chickens

A digestibility experiment was conducted to evaluate the effects of dietary exogenous monocomponent protease on the coefficient of apparent total tract digestibility (ATTD) and coefficient apparent ileal digestibility (AID) of amino acids in meat and bones meal (MBM), poultry byproducts meal (PBPM), and feather meal (FM). A total of 512 Cobb-500 male broiler chickens (aged 14 d) were randomly placed into 64 metabolism cages (8 birds per pen) and were allocated to eight treatments with eight replicates in a semi-controlled environmental room. The experimental diets consisted of the basal diet (corn/SBM) and the replacement of 300 g/kg on a weight basis with MBM, PBPM, or FM. The excreta were collected during 3 d (19 to 21 d), and the ileal digesta (using Celite as an indigestible marker) only 1 d (21 d). The protease contained 75,000 PROT units/g. The use of the enzyme increased (P < 0.05) ATTD for alanine, cysteine, glycine, and threonine in the basal diet and AID for the amino acids alanine, cysteine, glycine, lysine, threonine, and valine for the basal diet (vegetable). Regarding meals, there was an increase (P < 0.05) in the amino acid digestibility in large part due to the amino acids of MBM (14) and PBPM (9), with only five amino acids for FM. The amino acids glycine and threonine showed increases (P < 0.05) in both total and ileal digestibility for all animal meals and for the diet based on corn and soybean meal, which indicates a high specificity of the enzyme for these amino acids. The overall results obtained in this study found satisfactory effectiveness of this exogenous protease. The total collection method was lower by 1.83% of amino acids digestibility than the ileal method.

Comparative study of protease hydrolysis reaction demonstrating Normalized Peptide Bond Cleavage Frequency and Protease Substrate Broadness Index

Two commercial proteases (subtilisin-typed FNA from Bacillus amyloliquefaciens, and chymotrypsin-like NPP from Nocardiopsis prasina), porcine pepsin, porcine pancreatin having protease activity and their combinations were studied in vitro by LC-MS for their ability to digest soy protein isolate (SPI) under conditions close to those found in the stomach (pH 3.7) and small intestine (pH 6.5). The total number of peptides generated, and their size distribution were obtained under each set of the digestion conditions. These peptides were grouped according to their C-terminal amino acid (AA) residue (P1) and mass, based on which two concepts were proposed, i.e., Normalized Peptide Bond Cleavage Frequency (NPBCF) and Protease Substrate Broadness Index (PSBI). At pH 3.7, FNA+pepsin increased PSBI vs. pepsin alone by 2.7 and 4.9 percentage points (p.p.) at a SPI:protease ratio of 20:1 and 100:1, respectively. At pH 6.5, FNA+pancreatin improved PSBI by 9.1 and 10.2 p.p. at SPI:protease 20:1 and 100:1, respectively, vs. pancreatin alone. NPP generated 38% more peptides than FNA when administered with pancreatin at SPI:protease 200:1:1 and pH 6.5, but FNA alone (28.9) or FNA+pancreatin (29.1) gave a higher PSBI than pancreatin (22.2), NPP (20.3) and NPP+pancreatin (22.0). At pH 3.7 FNA generated 59% and 39% of peptides of pepsin at SPI:protease of 20:1 and 100:1, respectively, and both groups of peptides had similar size distribution. At pH 6.5 more small sized peptides were generated by FNA or FNA+pancreatin than pancreatin and NPP alone or pancreatin+NPP. In conclusion, FNA showed complementary effects with pepsin and pancreatin in terms of PSBI and generated more small sized peptides compared to NPP.

The effect of protease and Bacillus licheniformis on nutritional value of pea, faba bean, yellow lupin and narrow-leaved lupin in broiler chicken diets

1. This study investigated the nutritional value (digestibility of ileal crude protein and amino acids (AAs)) and the AMEN value of legumes (pea, faba bean, yellow lupin, and narrow-leaved lupin) with or without protease. 2. Two hundred, one-day-old, male Ross 308 broiler chickens were randomly allocated to ten groups. Each group received one of five different protein raw materials - either peas, faba beans, yellow lupins or narrow-leaved lupins, with or without protease produced from Bacillus licheniformis. The birds were kept in individual cages. Nutrient digestibility was calculated using the difference method. The total duration of the study was 23 d, and the study involved two phases - accommodation phase (d 1-18) and experimental phase (d 18-23). 3. The effect of protease on response traits was not consistent between the legumes. The enzyme increased the digestibility of some AAs in the pea (arginine, leucine, phenylalanine, histidine, tyrosine, alanine, and proline), faba bean (lysine, arginine, glycine, and asparagine), and yellow lupin diets (lysine, valine, and serine), but this effect was not observed in the narrow-leaved lupin diet. The change in AMEN values due to protease addition was only statistically significant for the pea diet (P < 0.05), whereas in the case of other legume species, the difference was insignificant (P > 0.05). 4. Exogenous protease increased the digestibility of AAs present in pea, faba bean, and yellow lupin seeds but not in narrow-leaved lupin diets. The AMEN value of peas increased with protease supplementation, but no effect of protease was found for the AMEN values of faba bean and both the lupin diets.

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

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

Factors affecting energy metabolism and evaluating net energy of poultry feed

Different energy evaluating systems have been used to formulate poultry diets including digestible energy, total digestible nutrients, true metabolizable energy, apparent metabolizable energy (AME), and effective energy. The AME values of raw materials are most commonly used to formulate poultry diets. The net energy (NE) system is currently used for pig and cattle diet formulation and there is interest for its application in poultry formulation. Each energy evaluating system has some limitations. The AME system, for example, is dependent on age, species, and feed intake level. The NE system takes AME a step further and incorporates the energy lost as heat when calculating the available energy for the production of meat and eggs. The NE system is, therefore, the most accurate representation of energy available for productive purposes. The NE prediction requires the accurate measurement of the AME value of feed and also an accurate measurement of total and fasting heat production using nutritionally balanced diets. At present, there is limited information on NE values of various ingredients for poultry feed formulation. The aim of this review is to examine poultry feed energy systems with the focus on the NE system and its development for chickens.

Standardized ileal digestible amino acid and metabolizable energy content of wheat from different origins and the effect of exogenous xylanase on their determination in broilers

This study was conducted to determine the standardized ileal digestible amino acids (SID AA) and nitrogen-corrected apparent metabolizable energy (AMEn) contents of 6 wheats from different origins in China and incidentally to investigate the effects of exogenous xylanase addition on SID AA and AMEn determination in broiler chicks. A total of 480 chicks were divided into 48 cages of 10 birds each balanced for body weight and fed 8 types of diets in a completely randomized design (6 replicated cages per diet) from 21 to 26 d of age. The individual wheat constituted the only source of crude protein in a semi-purified experimental diet. A nitrogen-free diet was designed to estimate basal endogenous AA loss and determine the SID AA. Titanium oxide (0.3%) was used as an indigestibility marker, and nutrient digestibility and retention were determined by the substitution method. From day 24 to 26, excreta samples were collected for AMEn determination. On day 26, the birds were euthanized, and ileum contents were obtained for AA digestibility determination. Wheat from Gansu had greater (P < 0.05) SID AA contents except Lys, Thr, Phe, and Cys, with a higher (P < 0.001) AMEn (11.83 MJ/kg) than the other wheats. The SID content of mean indispensable amino acids and dispensable amino acids were 87.35% and 88.17%, respectively, and the average AMEn value of 6 wheats was 11.14 MJ/kg. Compared with the diet without xylanase, the added xylanase resulted in higher (P < 0.05) SID contents of Met, Lys, Trp, Arg, Ile, Leu, Val, Gly, Asp, Glu, Pro, and Ala; the SID AA values were raised by 1.96% (mean of all AA); and the AMEn content was significantly increased (+0.87 MJ/kg) (P < 0.05). In conclusion, origins of wheats have significant effects on SID AA and AMEn values which were positively correlated with crude protein content of wheat; exogenous xylanase addition to a wheat-based poultry diet could significantly improve SID AA and AMEn contents for broilers.