The effects of fermentation and enzymatic treatment of pea on nutrient digestibility and growth performance of broilers F. Goodarzi Boroojeni 1 † , M. Senz 2 , K. Koz ł owski 3 , D. Boros 4 , M. Wisniewska 4 , D. Rose 5 , K. Männer 1 and J. Zentek 1 1 Department of Veterinary Medicine, Institute of Animal Nutrition, Freie Universität Berlin, Königin-Luise-Str. 49, 14195 Berlin, Germany; 2 Department Bioprocess Engineering and Applied Microbiology, Research and Teaching Institute for Brewing in Berlin, Institute of Biotechnology and Water, Seestrasse 13, 13353 Berlin, Germany; 3 Department of Poultry Science, Faculty of Animal Bioengineering, University of Warmia and Mazury in Olsztyn, Oczapowskiego 5, 10-719 Olsztyn, Poland; 4 Laboratory of Quality Evaluation of Plant Materials, Institute of Plant Breeding and Acclimatization – National Research Institute, 05-870 Radzikow, Blonie, Poland; 5 Department of Food Biotechnology and Food Process Engineering, Berlin University of Technology, Seestrasse 13, 13353 Berlin, Germany (Received 11 October 2016; Accepted 30 January 2017; First published online 18 April 2017) The present study examined the impacts of native, fermented or e nzymatically treated peas ( Pisum sativum L. ) inclusion in broiler diets, on growt h performance and nutrient digestibility. For the fermentatio n process, Madon na pea was mixed with water (1/1) containing 2.57 × 10 8 Bacillus subtilis (GalliPro ® ) spores/kg pea and then , incub ated for 48 h at 30 °C. For the e nzymatic treatment process, the used water for doug h production contained three enz ymes, AlphaGal TM ( α -galactosidase), RONOZYME ® ProAct and VP (protease and pectinases respectiv ely – DSM, Switzerland) and the pea dough incubated for 24 h at 30°C. Nine corn-wheat- soybean diets were formulat ed by supplying 10%, 20% and 30% of the required CP with eith er native, fermented or enzymati cally treated peas. Perf ormance was recorded weekly and at the end of the experiment (day 35), apparent ileal digestibility (AID) of CP, amino acids (AA), crude fat, starch, Ca, P and K were determ ined. Data were subjected to ANOVA using GLM procedu re with a 3 × 3 factorial arran gement of trea tments. Both processes reduced α -galactosides, phytat e, trypsin inh ibitor activity and resist ant starch in peas. Increa sing levels of pea products up to 300 g/kg diet, redu ced BW gain and feed intake ( P ⩽ 0.05). Broilers fed diets containing enzymati cally treated pea had the best feed conversion ratio at day 35. Different types of pea product and thei r inclusion level s had no effect on AID of all nutrient s. The intera ction between typ e of the pea prod ucts and inclusion levels w as signi fi cant for AID of starch. For nativ e pea diets, 10% group showed similar AID of starch to 20% native pea but it had higher AID than 30% native pea. For ferme nted and enzymatically treated groups, all three levels displa yed similar AID of starch. In conclusion, enzymatic trea tment and ferme ntation could improve the nutr itional quality of pea. Inclusion of enzymatically trea ted pea in broiler diets could improve bro iler performance compared with oth er pea products while, it disp layed neither positive nor negative impact on nutrient digestibility. The present fi ndings indicate the feasibility of these process es, particularly enzymati c treatment, for im proving the nutritional quality of pea as a protein source for broiler nutrition. Keywords: anti-nutritional factors, enzymatic treatment, legumes, solid state fermentation, α -galactosides Implications There is an urgent need for new plant proteins for poultry nutrition. As is, the majority of protein needs for poultry production are covered by the soybean products. The dependence of European feed production industry on soybean as well as the growing economic, environmental and ethical concerns on the loss of ecologically important rainforests have led to an increasing demand for home- grown and sustainable protein sources (e.g. European domestic grain legumes) for feeding livestock. The present study aimed to evaluate innovative and classic biotechno- logical approaches for production of high quality alternatives for soybean meal from domestic European peas. Introduction Soybean meal (SBM) is the most common plant protein source in poultry nutrition. Environmental factors remarkably limit cultivation of soybean in many parts of the world, especially Europe. In Europe, domestic legumes like peas, beans and lupines or oilseeds like rapeseed can be alternative plant protein sources. Peas have relatively high CP. They also can potentially provide considerable † E-mail: [email protected] Animal (2017), 11:10 , pp 1698 – 1707 © The Animal Consortium 2017 doi:10.1017/S1751731117 000787 animal 1698 amount of energy due to their high starch contents. How- ever, peas contain also variable amounts of anti-nutritional factors (ANF) such as α -galactosides, trypsin inhibitors (TI), resistant starch (RS), pectin, tannins, lectin, phytic acid and non-starch polysaccharides (NSP), which can signi fi cantly impair the digestive process especially in young chicks. This may lead to pancreatic hypertrophy, increased nutritional requirement for sulfur-containing amino acids (AA) and fi nally poor bird performance (Igbasan and Guenter, 1996; Nalle et al ., 2011; Frikha et al ., 2013). Different processes like soaking, autoclaving, dehulling and micronization followed by air classi fi cation have been proposed to improve the nutritional value of peas for poultry (Igbasan and Guenter, 1996; Laudadio et al ., 2012; Frikha et al ., 2013). These various processing techniques tended to reduce the content of ANF in peas but not ef fi cient enough to be practically used in poultry feed production. Fermentation processes have been used for centuries in human food production. Fermentation of legumes could eliminate ANF, for example tannins, TI, α -galactosides and modify AA pro fi le by microbial synthesis and breakdown (Ouoba et al ., 2003; Ouoba et al ., 2007; Gefrom et al ., 2013). Moreover, fermentation of an ingredient could provide a high number of bene fi cial microorganisms with probiotic effects on the microbiology and morphology of the gastrointestinal tract (GIT). Fermentation of rapeseed meal (RSM) could reduce glucosinolate (Chiang et al ., 2010) and phytic acid, while increased CP (Nair and Duvnjak, 1990). One of the major bene fi cial impacts of fermentation processes on ANF seems to be through enzymatic digestion. Using enzymes as feed additives in poultry diets could inactivate or/and eliminate certain ANF, improve the digestive process and availability of nutrients that were physically or chemically sequestered by ANF substances (Bedford, 2000). The retention time of feed in the GIT of poultry, especially broilers, is very short (~2 to 4 h) and can vary depending on chemical and physical characteristics (i.e. particle size, feed form, NSP concentration, etc.) of the feed. On the other hand, the optimum pH of most exogenous enzymes is between 4 and 6. Consequently, because of the GIT pH and the fact that enzymes can be subjected to hydrolysis by endogenous proteolytic enzymes in the GIT, the degradation activity of exogenous enzymes seems mainly limited to the crop, proventriculus and gizzard (Ravindran, 2013). The short retention time of digesta in the proximal GIT (60 to 90 min) and the wide range of pH which feed encounters along the poultry GIT limits the ef fi ciency of exogenous enzymes (Svihus et al ., 2002; Ravindran, 2013). Fermentation with probiotic mi croorganisms and treatment of peas for a certain period of time with appropriate exoge nous enzymes in a moist enviro nment may be an effective app roach to improve the n utritional quality of pe as. Despite promising nutritional effects of fermentation and enzymatic treatment of plant materials, the re is little i nformation available assessing the effects of these technologi cal processes on nutritional quality of pea as well as on p erformance and nutrient diges ti- bility in broilers. Therefore, the pre sent study was conducted to investigate the effects of d ifferent inclusion levels o f native, fermented or enzymatically treated pea products on perfor- mance and nutrient d igestibility in broilers. Material and methods A commercial batch of Madonna pea ( Pisum sativum L.) was hammer milled as full seeds (includ ing hulls) to 2 mm screen size. The ground pea (90 9 g/kg DM) was used for the continuous produ ction of pea dough (500 g/kg DM) during fermentation and enzymatic treatment as well as for the anim al trials, as native pea in th e diets. Solid state fermentation A commercial probiotic, GalliPro ® (EU authorized probiotic to be used in broiler feed) containing 1.60 × 10 9 spores/g of Bacillus subtilis (Chr. Hansen, Denmark) was employed for the solid state fermentation (SSF ) process. In the fermentation process the used water for dough producti on was inoculated with the probiotic spore, resulting in fi nal concentration of ~2.57 × 10 8 B. subtilis spores/kg pea. The dough was pumped in internal cathodic protected (ICP) tanks and incubated in temperature controlled containers (30°C) for 48 h. Treatment with exogenous enzymes For enzymatic treatment, th e used water for dough productio n contained three different commercial exogenous enzymes plus organic aci ds mixture (10 ml/kg pea doug h; 8 ml lactic acid a nd 2 ml acetic acid). The acidi fi cation of water, resulting in a fi nal pH of 4.5 in the dough, was to inhibit the growth of pea associated microorganisms an d uncontrolled fermentation of pea by its associated microorg anisms (spoilage) during the incubation time. Three commercial enzymes used for enzymatic treatment process were 0.1 g/kg pea AlphaGal TM (Kerry EMEA, USA) containing an α -galactosidase (enzyme activity: 11 5 μ /kg pea), 0.2 g/kg pea RONOZYME ® ProAct (DSM, Switzerland) containing a protease ( enzyme activity: 15 000 μ /kg pea), and 0.2 g/kg pea RONOZYME ® VP (DSM) containing a blend of β -glucanase and pectinase s (enzyme activities: 10 μ /kg pea). After fi lling in ICP tanks, the pre pared dough was incubated for 24 h at 30°C. The eff e cts of fermentation and enzymatic treatment on nutrients and ANF com position of pea p roducts are presented in Tables 1 and 2, respectively . Drying and milling of processed pea After the processes, the wet materials were simultaneously dried and ground using an U ltra-Rotor dryer mill (Ultra-Rotor Type U III a, Jäckering Mühlen- und Nährmittelwerke GmbH, Hamm, Germany). The dryer, with generating of a very high turbulence and using of heated air (6000 m 3 /h), simultaneously milled and dried the material. The drying process lasted < 3s (throughput of 16 0 kg dry product per h). The maxim um product temperature was below 75°C. In total, seven samples from dried products were analyzed c oncerning their particle size via laser particle size analyzer (Type 930; Cilas S.A., O r l é a n s ,F r a n c e ) .T h em e a np a r t i c l es i z eo ft h e fi nal products Nutritional quality improvement of pea for broiler 1699 was ~ 55 ± 5.2 µ m. The DM content of the fi nal pro ducts was about 921 g/kg. Animals and experimental design The experimental protocol was approved by the State Of fi ce of Health and Social Affairs Berlin (LAGeSo Reg. No. 114-G 0203/14). Nine starter (days 1 to 21) and nine grower (days 22 to 35) diets were formulated by supplying 10%, 20% and 30% of the required CP with three different pea products tested (native, fermented and enzymatically treated peas). The diets were formulated to be isocaloric and isonitrogenous for each phase and, meet or exceed the recommendations of the Society of Nutritional Physiology (GfE, 1999). The grower diet contained 5 g titanium dioxide per kg feed (Sigma Aldrich, St. Louis, MO, USA) as an indigestible marker to allow for the determination of ileal apparent nutrient digestibility. The compositions of the starter and grower experimental diets are shown in Tables 3 and 4, respectively. One th ou sand an d eig hty, 1- da y- ol d male bro il er chi ck s (Cob b 50 0) , were ra ndom ly al lo ca te d int o 72 pe ns (2 .20 × 1. 80 m) wi th a s oftw oo d sh av ing fl oor. Us in g a com- plet el y rand omiz ed desi gn with a 3 × 3 facto ri al arra ng em en t of trea tm en ts, th e nin e diff eren t diet s were ra nd o mly ass ig ne d to bird s wi thi n pens (e ight re pl ic ate- pe ns pe r die t). The diets were offered in mash. The experiment lasted 35 days. The temperature was 33°C for the fi rst 7 days of the experiment, after which the temperature was gradually reduced by 3°C per week until reaching 24°C. The lighting program consisted of full time light for the fi rst 3 days and 20 h of light until day 7 and 16 h of light thereafter. All birds had access to the experimental diets and water ad libitum . Performance measurements BWs of the chicks were recorded at day 1 and weekly during the experiment. Feed intake (FI) was recorded weekly and feed conversion ratio (FCR) was calculated. The birds were healthy in the entire experiment and the total mortality was about 2%. Performance variables are presented in Table 5. Nutrient digestibility and relative organ size At the end of the experiment, nine birds per pen were randomly selected, stunned and killed by exsanguination. The ileum was dissected from Meckel ’ s diverticulum to the ileo – caeco – colic junction and the digesta was collected from the distal 2/3 for the apparent ileal digestibility (AID) determinations. The digesta of all the birds within each pen were pooled and immediately frozen ( − 80°C) until further analysis. The pooled digesta was freeze dried before chemical analysis. The following formula was used for AID calculation: AID of nutrient = 1 ½ð concentration of marker in feed = concentration of marker in ileum Þ ´ ð concentration of nutrient in ileum = concentration of nutrient in feed Þ The AID of nutrients are presented in Table 6. Another two birds per pen were weighed, and killed by exsanguination. Carcasses were dissected and the proven- triculus, gizzard, duodenum, jejunum, ileum, cecum and pancreas were removed and their empty weights were recorded. Organ size was expressed as a percentage of live BW (Table 7). Table 1 Analyzed nutrient composition of pea products Native pea 1 Fermented pea 2 Enzymatically treated pea 2 Nutrient composition (g/kg DM) Crude fat 12.1 6.5 6.5 CP 228 238 230 Starch 442 431 434 Ala 9.9 9.9 9.6 Arg 19.1 16.4 18.6 Asp 25.2 24.0 24.6 Cys 5.3 5.2 4.9 Glu 23.9 22.7 22.9 Gly 9.7 9.7 9.5 His 8.1 7.9 7.8 Ile 8.6 8.8 8.7 Leu 15.8 15.8 15.5 Lys 16.6 16.1 16.2 Met 2.6 2.6 2.4 Orn 0.0 2.4 0.0 Phe 10.9 10.9 11.1 Pro 9.9 10.2 9.1 Ser 11.9 11.0 11.4 Thr 9.0 8.9 8.7 Tyr 6.9 6.4 7.1 Val 9.9 10.0 9.9 Total AA 206 205 201 Minerals and trace elements Ca (g/kg DM) 0.73 0.90 0.82 K (g/kg DM) 7.60 8.18 8.16 Na (g/kg DM) 0.265 0.230 0.317 P (g/kg DM) 3.17 3.29 3.24 Cu (mg/kg DM) 5.5 6.5 6.5 Fe (mg/kg DM) 42 54 58 Mg (g/kg DM) 1.27 1.21 1.21 Mn (mg/kg DM) 10 11 10 Zn (mg/kg DM) 23 26 28 Bacterial metabolites ( µ mol/g as fed) Acetic acid 2.2 17.8 56.1 Propionic acid ND ND ND i -Butyric acid 3 ND ND ND n -Butyric acid 3 ND ND ND i -Valeric acid 3 0.8 4.8 1.4 n -Valeric acid 3 14.8 8.6 23.9 L -Lactate 0.52 176 184 D -Lactate 0.05 173 2.0 Ammonium 0.05 32 1.7 ND = not detected. 1 Dry matter of native pea: 909 g/kg. 2 Dry matter of fermented and enzymatically treated pea: 921 g/kg. 3 Branched chain volatile fatty acids. Goodarzi Boroojeni, Senz, Koz ł owski, Boros, Wisniewska, Rose, Männer and Zentek 1700 Chemical analysis Basic composition analysis were conducted, using standard procedures (Naumann and Bassl er, 2004). A commercial enzy- matic test (Starch UV-Test; R-Bi opharm, Darmsta dt, Germany) was applied to determine starch c ontent (Nauma nn and Bassler, 2004). The P con tent was measured using the amm onium vanadate/molybdate m ethod (Gericke and Kurmies, 1952). Other minerals were analyzed by using an atomic absorption Table 2 Anti-nutritional factors of pea products (mean ± SD) Fermentation Enzymatic treatment Anti-nutritional factors Native pea Fermented pea Alteration by fermentation 1 Enzymatically treated pea Alteration by treatement 1 Insoluble-NSP (g/100 g DM) 2 11.3 ± 0.10 11.1 ± 0.08 − 1.90% 9.9 ± 0.11 − 12.60% Soluble-NSP (g/100 g DM) 2 0.91 ± 0.02 1.06 ± 0.00 + 15.40% 1.01 ± 0.01 + 11.00% Resistant starch (g/100 g DM) 2 3.25 ± 0.02 0.73 ± 0.00 − 77.50% 0.81 ± 0.00 − 75.10% Total dietary fi ber 3 (g/100 g DM) 2 18.1 ± 0.11 16.2 ± 0.05 − 10.80% 14.8 ± 0.12 − 18.00% Trypsin inhibitor activity (TIU) 4 (mg/g DM) 2 0.67 ± 0.01 0.23 ± 0.01 − 65.70% 0.50 ± 0.01 − 25.40% Raf fi nose equivalents (mol/g DM) 5 97.9 ± 4.44 30.7 ± 4.97 − 68.60% 48.9 ± 10.50 − 50.00% Phytic acid (g/100 g DM) 5 0.92 ± 0.02 0.77 ± 0.01 − 16.40% 0.47 ± 0.01 − 49.20% NSP = non-starch polysaccharides. 1 Compared with native pea. 2 Data were obtained from duplicate measurements and are stated as mean value ± standard deviation. 3 Cellulose, hemicellulose, lignin, gums, modi fi ed celluloses, mucilages, ligosaccharides, and pectins and associate d minor substan ces, such as waxes, cutin and suberin. 4 Trypsin inhibitor activity unit. 5 Data were obtained from triplicate measuremen ts and are stated as mean value ± standard deviation. Raf fi nose equivalents represent the number of α -1-6-glycosidic bonds that is cleavable in 1 mol of raf fi nose. Table 3 Ingredients (g/kg unless noted) and analyzed nutrient composition of the starter (1 to 21 days) diets 1 Pea Native Fermented Enzymatically treated Level of protein requirement supplementation by pea products 10% 20% 30% 10% 20% 30% 10% 20% 30% Ingredient (g/kg) Pea product 106.0 212.0 318.0 100.6 201.2 301.8 104.4 208.7 313.1 Maize 234.3 154.5 75.5 243.2 170.3 98.2 237.4 159.2 83.1 Wheat 200.0 200.0 200.0 200.0 200.0 200.0 200.0 200.0 200.0 Soybean meal (CP 440 g/kg) 329.0 288.7 249.5 325.8 285.5 244.5 327.0 288.0 247.8 Soybean oil 82.0 91.5 99.6 81.7 90.0 98.0 82.4 91.0 98.8 Premix (containing 330 g/kg NaCl) 2 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 Monocalcium phosphate 14.8 15.8 16.2 14.8 15.5 16.2 15.0 15.8 16.2 Limestone 14.4 14.3 14.2 14.4 14.2 14.2 14.3 14.2 14.0 L -Lysine-HCL 2.6 4.2 5.9 2.6 4.3 6.0 2.6 4.2 5.9 DL -Methionine 3.4 4.3 5.1 3.4 4.3 5.1 3.4 4.2 5.1 L -Threonine 1.2 2.2 3.2 1.2 2.2 3.2 1.2 2.2 3.2 L -Tryptophan 0.3 0.5 0.8 0.3 0.5 0.8 0.3 0.5 0.8 TiO 2 3 –––––– – – – Analyzed nutrient composition (g/kg) CP 232 221 229 225 224 223 223 221 222 Crude fat 101 113 120 103 107 111 104 109 117 Starch 265 241 259 253 267 248 259 243 267 P 7.3 7.5 7.3 7 7.1 7.6 7.2 7.3 7.2 Ca 9.2 9.1 9.3 9.5 8.8 9.4 9.3 9 9.2 Na 1.9 1.9 2.0 2.0 1.9 1.8 2.0 1.9 2.0 Ash 59 59 58 59 59 58 59 59 58 Calculated AME N (MJ/kg) 4 12.57 12.57 12.57 12.57 12.57 12.57 12.57 12.57 12.57 1 As-fed basis. 2 Contents per kg diet: 4800 IU vitamin A; 480 IU vitamin D 3 ; 96 mg vitamin E ( α -tocopherole acetate); 3.6 mg vitamin K 3 ; 3 mg vitamin B 1 ; 3 mg vitamin B 2 ;3 0 m g nicotinic acid; 4.8 mg vitamin B 6 ;2 4 µ g vitamin B 12 ; 300 µ g biotin; 12 mg calcium pantothenic acid; 1.2 mg folic acid; 960 mg choline chloride; 60 mg Zn (zinc oxide); 24 mg Fe (iron carbonate); 72 mg Mn (manganese oxide); 14.4 mg Cu (copper sulfate-pentahydrate); 0.54 mg I (calcium iodate; 0.36 mg Co (cobalt- (II)-sulfate- heptahydrate); 0.42 mg Se (sodium selenite); 1.56 g Na (sodium chloride); 0.66 g Mg (magnes ium oxide). 3 Indigestible marker (Sigma Aldrich, St. Louis, MO, USA). 4 Nitrogen-corrected apparent metabolizable energy estimated from chemical composition (based on the EU Regulation – Directive 86/174/EEC): 0.1551 × %C P + 0.3431 × % crude fat + 0.1669 × % starch + 0.1301 × % total sugar. Nutritional quality improvement of pea for broiler 1701 spectrophotometer (AAS vario ® ; Analytik Jena, Jena, Germany). TiO 2 content was measured using t he method described by Short et al . (1996). The AA analyses were conducted u sing a Biochrom 20 Plus amino acid analyzer (Amersham Pharmacia Biotech, Piscataway, NJ, USA) using standard method (VDLUFA, 2003). The soluble and ins oluble NSP were determi ned using Englyst and Cummings (1984) method. The American Table 4 Ingredients (g/kg unless noted) and analyzed nutrient composition of the grower (22 to 35 days) diets 1 Pea Native Fermented Enzymatically treated Level of protein requirement supplementation by pea products 10% 20% 30% 10% 20% 30% 10% 20% 30% Ingredient (g/kg) Pea product 89.1 178.1 267.2 84.5 169.1 253.6 87.7 175.3 263.0 Maize 280.7 210.0 146.7 287.2 227.1 166.8 282.6 218.3 153.4 Wheat 300.0 300.0 300.0 300.0 300.0 300.0 300.0 300.0 300.0 Soybean meal (CP 440 g/kg) 215.7 186.3 150.4 214.5 180.2 146.0 215.4 182.3 148.8 Soybean oil 64.2 72.0 78.5 63.6 70.0 76.6 64.0 70.6 77.5 Premix (containing 330 g/kg NaCl) 2 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 Monocalcium phosphate 11.9 12.1 12.7 11.8 12.1 12.7 11.9 12.1 12.8 Limestone 11.0 11.1 11.0 11.0 11.1 10.8 11.0 11.1 10.9 L -Lysine-HCL 4.3 5.6 7.0 4.3 5.7 7.1 4.3 5.6 7.1 DL -Methionine 3.2 3.9 4.6 3.2 3.9 4.5 3.2 3.9 4.6 L -Threonine 2.1 2.9 3.7 2.1 2.8 3.7 2.1 2.8 3.7 L -Tryptophan 0.8 1.0 1.2 0.8 1.0 1.2 0.8 1.0 1.2 TiO 2 3 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 Analyzed nutrient composition (g/kg) CP 188 189 185 186 188 187 187 187 190 Crude fat 90 88 96 86 88 88 86 88 92 Starch 341 339 340 325 313 346 369 345 323 P 6.1 5.8 5.7 6.0 6.1 6.1 6.0 5.9 6.0 Ca 7.7 7.2 7.1 7.5 7.4 7.4 7.7 7.7 7.7 Na 1.8 1.6 1.9 1.9 1.8 1.8 1.9 1.9 2.0 Ash 54 52 52 54 53 52 54 54 53 Calculated AME N (MJ/kg) 4 12.65 12.65 12.65 12.65 12.65 12.65 12.65 12.65 12.65 1 As-fed basis. 2 Contents per kg diet: 4800 IU vitamin A; 480 IU vitamin D 3 ; 96 mg vitamin E ( α -tocopherole acetate); 3.6 mg vitamin K 3 ; 3 mg vitamin B 1 ; 3 mg vitamin B 2 ;3 0 m g nicotinic acid; 4.8 mg vitamin B 6 ;2 4 µ g vitamin B 12 ; 300 µ g biotin; 12 mg calcium pantothenic acid; 1.2 mg folic acid; 960 mg choline chloride; 60 mg Zn (zinc oxide); 24 mg Fe (iron carbonate); 72 mg Mn (manganese oxide); 14.4 mg Cu (copper sulfate-penta hydrate); 0.54 mg I (calcium iodate; 0.36 mg Co (cobalt-(II)-sulfate- heptahydrate); 0.42 mg Se (sodium selenite); 1.56 g Na (sodium chloride); 0.66 g Mg (magnes ium oxide). 3 Indigestible marker (Sigma Aldrich, St. Louis, MO, USA). 4 Nitrogen-corrected apparent metabolizable energy estimated from chemical composition (based on the EU Regulation – Directive 86/174/EEC): 0.1551 × %C P + 0.3431 × % crude fat + 0.1669 × % starch + 0.1301 × % total sugar. Table 5 Effect of the experimental diets on the performance variables (mean 1 values) Type of the pea products Level 2 P value Native Fermented Enzymatically treated 10% 20% 30% SEM Type 3 Level Type × level BWG (1 to 21 days) 690 685 696 718 a 691 ab 662 b 8.3 Ns 4 0.025 Ns FI (1 to 21 days) 900 881 879 939 a 883 ab 838 b 11.7 Ns 0.002 Ns FCR (1 to 21 days) 1.31 1.29 1.26 1.31 1.28 1.27 0.009 Ns Ns Ns BWG (22 to 35 days) 1119 1078 1093 1133 a 1117 a 1041 b 8.9 Ns < 0.001 Ns FI (22 to 35 days) 1783 a 1712 b 1699 b 1795 a 1753 a 1645 b 14.7 0.010 < 0.001 Ns FCR (22 to 35 days) 1.59 a 1.59 a 1.55 b 1.59 1.57 1.58 0.006 0.017 Ns Ns BWG (1 to 35 days) 1809 1763 1789 1851 a 1808 a 1702 b 14.1 Ns < 0.001 Ns FI (1 to 35 days) 2683 a 2593 ab 2577 b 2734 a 2636 ab 2483 b 21.9 0.039 < 0.001 Ns FCR (1 to 35 days) 1.48 a 1.47 a 1.44 b 1.48 1.46 1.46 0.005 0.002 Ns Ns SEM = pooled standard error of mean; FCR = feed conversion ratio (g of feed intake/g of BW gain); FI = feed intake (g); BWG = BW gain (g) a,b Means of each main factors with different superscripts in a row differ signi fi cantly ( P ⩽ 0.05). 1 Data are means of eight replicate pens with 15 birds per pen. 2 Level of protein requirement supplementation by pea products. 3 Type of the pea products. 4 Not signi fi cant ( P > 0.05). Differences were considered signi fi cant at P ⩽ 0.05. Goodarzi Boroojeni, Senz, Koz ł owski, Boros, Wisniewska, Rose, Männer and Zentek 1702 Association of Cereal Chemists (2003) methods were used to determine RS (AACC 32-40.01) and total dietary fi ber (TDF; AACC method 32-25 – Uppsala method). Trypsin inhibitor activity (TIA) was measure d according to Kakade et al . (1974) method. The α -galactosides content (in pea mainly raf fi nose, stachyose and verbascose) was determined via enzymatic Table 6 Effect of the experimental diets on the apparent ileal digestibility (AID) of nutrient (mean 1 values) in broilers (day 35) Type of the pea products Level 2 P value Native Fermented Enzymatically treated 10% 20% 30% SEM Type 3 Level Type × level Ala 0.82 0.82 0.81 0.81 0.82 0.82 0.005 Ns 4 Ns Ns Arg 0.89 0.89 0.89 0.88 0.89 0.89 0.003 Ns Ns Ns Asp 0.80 0.80 0.80 0.79 0.80 0.81 0.004 Ns Ns Ns Cys 0.75 0.75 0.74 0.74 0.75 0.75 0.006 Ns Ns Ns Glu 0.86 0.86 0.85 0.85 0.86 0.86 0.003 Ns Ns Ns Gly 0.78 0.79 0.78 0.78 0.78 0.79 0.005 Ns Ns Ns His 0.84 0.84 0.83 0.83 0.84 0.84 0.004 Ns Ns Ns Ile 0.83 0.83 0.83 0.83 0.82 0.83 0.006 Ns Ns Ns Leu 0.83 0.84 0.83 0.83 0.83 0.84 0.005 Ns Ns Ns Lys 0.89 0.90 0.89 0.88 b 0.89 ab 0.91 a 0.003 Ns 0.009 Ns Met 0.95 0.95 0.95 0.94 b 0.95 ab 0.96 a 0.002 Ns 0.007 Ns Phe 0.85 0.86 0.85 0.85 0.85 0.86 0.005 Ns Ns Ns Pro 0.82 0.83 0.83 0.82 0.82 0.83 0.005 Ns Ns Ns Ser 0.80 0.80 0.80 0.80 0.80 0.81 0.004 Ns Ns Ns Thr 0.82 0.82 0.82 0.80 b 0.82 ab 0.84 a 0.005 Ns 0.011 Ns Tyr 0.83 0.84 0.84 0.83 0.83 0.84 0.005 Ns Ns Ns Val 0.80 0.80 0.80 0.80 0.80 0.81 0.007 Ns Ns Ns Total AA 0.83 0.84 0.83 0.83 0.83 0.84 0.004 Ns Ns Ns CP 0.82 0.82 0.81 0.81 0.82 0.83 0.004 Ns Ns Ns CF 0.93 0.93 0.93 0.93 0.93 0.93 0.004 Ns Ns Ns Starch 0.92 0.96 0.96 0.96 0.94 0.93 0.004 < 0.001 < 0.001 0.018 P 0.60 0.62 0.60 0.61 0.62 0.61 0.010 Ns Ns Ns Ca 0.38 0.37 0.38 0.38 0.37 0.39 0.010 Ns Ns Ns K 0.85 0.85 0.83 0.84 0.85 0.84 0.004 Ns Ns Ns SEM = pooled standard error of mean; AA = amino acids; CF = crude fat. a,b Means of each main factors with different superscripts in a row differ signi fi cantly ( P ⩽ 0.05). 1 Data are means of eight replicate pens. Pooled digesta of nine birds per pen. 2 Level of protein requirement supplementation by pea products. 3 Type of the pea products. 4 Not signi fi cant ( P > 0.05). Differences were considered signi fi cant at P ⩽ 0.05. Table 7 Effect of the experimental diets on relative organ weight (day 35) of broilers 1 (mean 2 values) Type of the pea products Level 3 P value Native Fermented Enzymatically treated 10% 20% 30% SEM Type 4 Level Type × level Pancreas 0.18 0.19 0.18 0.19 0.18 0.18 0.004 Ns 5 Ns Ns Proventriculus 0.29 0.30 0.27 0.29 0.28 0.30 0.006 Ns Ns Ns Gizzard 1.66 a 1.41 b 1.40 b 1.46 1.48 1.53 0.031 < 0.001 Ns Ns Duodenum 0.71 a 0.67 ab 0.64 b 0.67 0.67 0.68 0.011 0.016 Ns Ns Jejunum 1.18 a 1.11 ab 1.08 b 1.12 1.15 1.10 0.018 0.050 Ns Ns Ileum 0.88 a 0.80 b 0.79 b 0.84 0.80 0.83 0.014 0.014 Ns Ns Small intestine 2.78 a 2.59 ab 2.50 b 2.63 2.63 2.62 0.036 0.004 Ns Ns Cecum 0.30 0.29 0.30 0.29 0.29 0.31 0.008 Ns Ns Ns SEM = pooled standard error of mean. a,b Means with different superscripts in a row differ signi fi cantly ( P ⩽ 0.05). 1 [Empty organ weight (g)/live BW (g)] × 100. 2 Data are means of eight replicate pens (two birds per pen). 3 Level of protein requirement supplementation by pea products. 4 Type of the pea products. 5 Not signi fi cant ( P > 0.05). Differences were considered signi fi cant at P ⩽ 0.05. Nutritional quality improvement of pea for broiler 1703 assay (raf fi no se/ D -galactose Assay Kit; Megazyme Interna- tional, Bray, Ireland), presented as raf fi nose equivalent (RE). Phytate was analyzed using phytate (total P) assay kit (Mega- zyme International). Determination of bacterial metabolites Determination of short chain fatty acids was performed by gas chromatography (Agilent Technologies 6890N coupled with an auto sampler G2614A and an auto injector G2613A; Santa Clara, CA, USA) using standar d procedure (S chäfer, 1995). The column was an Agilent 19 095N-123 HP-INNOWAX polyethylene glycol. Following standard procedure, D - and L -lactate were determined by HPLC, using an Agilent 1100 system with a Phenomenex C18 (4.0 × 2.0 mm) guard column followed by a Phenomenex Chirex 3126 ( D )-penicillamine column (150 × 4.6 mm) (Agilent Technologies). The UV detector wavelength was 253 nm and the column temperature was 35°C. The carrier was CuSO 4 in a gradient from 0.5 to 2.5 mmol/l with a fl ow rate of 1 ml/min at 35°C and the injection volume was 20 µ l. Ammonia was quanti fi ed using the Berthelot reaction assay. Brie fl y, 20 µ l of the sample was chlorinated with 10 0 µ lo f 0.2% alkali ne hypochloride ( Sigma Aldrich, Deisenh ofen, Germany) to convert NH 3 to chloramine (NH 2 Cl) following reaction with thymol to N-chloro -2-isopropyl-5-methylchinon- monoimin and furth er to indophenol u sing 100 µ lo f5 %p h e n o l nitropruss ide (Sigma Aldric h). After incubation for 100 min in microtitration plates at room temperature, a photometric measurement was carried out at 620 nm with a Tecan micro- titerplate reader (Tecan Austria GmbH, Grödig, Austria). Statistical analysis Data were subjected to ANOVA using the GLM procedure of SPSS 19.0 (SPSS Inc., Chicago, IL, USA) as a 3 × 3 factorial arrangement of treatments that included three pea products (native, fermented or enzymatically treated pea) and three different inclusion levels (10%, 20% or 30% of diet ’ s CP) as the main effects and their interactions. Treatment means were separated by the Tukey least signi fi cant difference post hoc test at P ⩽ 0.05 statistical level. Replicate-pen was the experimental unit for all variables measured. Results In fl uence of technological processing on nutrients and anti-nutritional factors of the pea products Except a reduction in crude fat (CF) and a negligible increase in CP, no other notable changes for the main nutrients like AA and starch were observed for the both processed pea products. Both processes caused a minor increase in the concentration of P, Ca, K, Fe and partially Zn. The Na content of enzymatically treated pea was higher than native and fermented ones. In accordance with pH value of fermented pea, which decreased from 6.34 down to 4.37 within 48 h incubation time, the concentration of acetic acid, L -lactate, D -lactate and ammonium in fermented pea were considerably higher than native pea. As expected, the pH value of the enzymatically treated pea did not vary with time (4.54 ± 0.14). The RE content of pea was reduced by 69% in the fermented end product (30.7 mol/g) and by 50% in the enzymatically treated one (48.9 mol/g). Fermentation decreased TIA in the pea (0.67 TIU mg/g) to approxima tely one third (0.23 TIU mg/g), whereas TIA in the enzymatically treated pea was ~25% (0.50 TIU mg/g) lower than the n ative pea. Enzymatic treatment caused a 49% reduction in phytic acid concentration, whereas the reduction by fermentatio n process was only of 16% (0.92 g phytate/100 g native pea). Both processes caused a slight increase in S-NSP and a slight reduction in I-NSP and TDF, with reductions being more pronounced for the enzymatically treated pea. More- over, a remarkable decrease in RS was observed in both processed peas (more than 75% reduction). Broiler performance Increasing the level of dietary peas in the diets up to 30% reduced BWG and FI of broilers ( P ⩽ 0.05). Pea processing decreased FI after day 21 ( P ⩽ 0.05), whereas broilers fed enzymatically treated pea had the best FCR for the growing and entire experimental period ( P ⩽ 0.05). At the end of the experiment, FI of birds fed enzymatically treated pea diets was considerably lower than those received native pea diets ( P ⩽ 0.05). Apparent ileal nutrient digestibility and relative organ size The AID of Thr, Lys and Met at 30% inclusion level was higher than 10% inclusion group ( P ⩽ 0.05). The interaction between type of the pea products and inclusion levels of peas was only signi fi cant for the AID of starch ( P ⩽ 0.05). Chicken fed 30% native pea die t had the lowe st AID of starch (0.89) among all the nine gr o ups and chicken f ed 10% fermented and enzymatically treated pea diets (0.97 and 0.97, respectively) had higher AID of starch compared with 20% and 30% native pea groups (0.93 and 0.89, respectively ). In native pea groups, AID of starch for 20% (0.93) an d 30% (0.89) native p ea diets were similar but 10% native pea diet (0.95) showed similar AID to 20% and higher AID than 30 % one ( P ⩽ 0.05). In fermented pea groups (0.97, 0.95 and 0 .95, respectively) as well as enzymatically treated groups (0.97, 0.96 and 0.96, respec- tively), all three levels had identical AID of starch. The size of gizzard, duodenum, jejunum and ileum, were signi fi cantly lower for birds fed enzymatically treated pea compared with those received native pea ( P ⩽ 0.05). The size of gizzard and ileum in broilers received fermented pea diets followed the course observed for those fed enzymatically treated peas ( P ⩽ 0.05). Discussion Fe rm en tat io n pro c es ses to im pr ove nu tr it io na l qu al ity of leg u me s, pa rt ic u lar ly s oy b ean , hav e b ee n stu d ie d for l on g (F en g et al ., 200 7) . Th e appl ic at i on of ex og en o us en zym es i n Goodarzi Boroojeni, Senz, Koz ł owski, Boros, Wisniewska, Rose, Männer and Zentek 1704 pou lt ry di ets to ove rc ome th e ne gat iv e im pac ts of AN F sub st an c es an d impr o ve the nut ri ti o na l qual it y of feed i s a com mo n pr a cti c e in p ou lt ry fe ed p ro d uct i on . Th e mai n li mi ts fo r opt im a l enz ym e res po ns es in p ou lt ry n ut rit i on see m to be th e re te nti o n ti me an d va ria ble pH in th e di ff ere nt seg men ts of th e GI T (A deo la an d Cow ieson , 20 11 ). S elec ti ve tr eat me nt by en zym es an d al so ferm enta tio n of SBM c ou ld el imin ate th e al ler geni c pro teins and sol uble car boh yd ra te s, an d led to a re duc tion in fi ber, TI , olig osac cha rid es an d lec tin s (Ber ro cos o et al ., 2 013) , cons eque ntl y, the y coul d impr ove gr owt h per form anc e and nut rien t di ge sti bili ty in pou ltry (F ri kha et al ., 201 3). Su bjec ting pea to fe rmen tati on with pr obi ot ic mi cro org anis ms or tre at me nt with ap pro pri ate ex oge nou s en zym es, may b e a sou nd alte rnat ive to imp rove fe edi ng va lue of pl an t pr ot ei n sour ces to rep la ce SB M in pou ltry di et. Fermentation of African locust bean ( Parkia bi globosa )a t pH 7.5 to 9 b y different Bacillus subtilis subspecies increased essential AA and un saturated fa tty acid s, for example linoleic and linoleni c acids content, and also d ecreased oligos accha- rides (Ouoba et al ., 2003 and 2007). Fermentation o f RSM with Lactobacillus ferm entum and B. subtilis increased CP, L ys, sulfur AA and considera bly decreased isothiocyanates (from 108.7 to 13.1 mmol/kg) (Xu et al ., 2012). In the present study none of the two processes modi fi ed the AA content of the peas, except a reduc tion in CF an d a slight in crease in CP. Si nce the alteration in fat content was also presented in the not fermented samples (enzymatically treated sample), it is very likely that fat reductio n was due to the lipase activity of peas. This is in accordance with other s tudy which reported a distinct reduction of lipids and an increase in lipase activity during fermentation of soybean by its associated (native fl ora – no bacteria added) mi croorganisms ( Ruiz-Teran and Owens, 1996). In the present study, the reason fo r observed minor increases in the concentration of analyz ed minerals by th e processes is not clear. Fermentation and enzymatic treatment of pea in lab scale did not cause any change in ash content of the fi nal products (unpublish ed data). Thus, considering the amount of water used for pea do ugh production (50%), this minor increases might be e xplained by mineral content o f the water in the production s ite (Jäck ering Mühlen - und Nährmittelwerke GmbH, Ham m, Germany) and also wear of metallic pieces in the Ultra-Rotor dryer. Increase in mineral content of poultry feed du e to the wear of metal lic pieces in hydrothermal processing mach ines has been reported before (Goodarzi Borooje ni et al ., 2016). Both types of pea process ing resulted in a remarkable decreas e in RS. The slight reductions in I-NSP and TDF o f the proces sed peas were more p ronounced for the enzymatically treated pea than the fermented one. Enzymatic treatment reduced TIA and phytic acid by 25% and 49%, while these were reduced by 66% an d 16% in the fermen ted pea. T he RE was re duced by 50% and 69 % in the enzymatically treated and fermented peas, respectively. The results are in accordance with recent study which showed that SSF of SBM with B. subtilis decreased the TIA of SBM up to 95% (Teng et al ., 2012). The changes in phytic acid, RE, I-NSP and TDF might be expl ained by activation of exo genous/ microbial enzymes and pea ’ s endog enous enzymes. Furthermore, the acidic pH value in the processed pe as might have induced a n increase in activity of endogeno us amylase and phytase (Selle et al ., 2000; A deola and Co wieson, 2011). The drastic pH drop during the SSF process seemed to be due to the accumulation of lactic and acetic acids, caused by the metabolic activity of native and added microorga nisms (Ying et al ., 2009). The high concentration of acetic and L -lactic acids in the enzyma tically treated pea w as mainly due to the add ition of organic a cids during the pro cessing. The increase of ammonium, valeric and D -lactic acids by enzymatic treatment could be because of activity and proliferation of the pea ’ s native micro fl ora as w ell as existent microor ganisms in the production enviro nment, which were able to survive and maintain their metabolic activity at the created acidic pH (4.5). The information available regarding the effects of enzy- matic treatment on nutrient and ANF composition of peas is scarce. In a broiler study, enzymatic treatment of pea with several carbohydrase enzymes (i.e. cellulase, pectinase, xylanase, glucanase, galactanase, and mannanase) and their combinations reduced arabinose, xylose, galactose, glucose, uronic acids and total NSP. These reductions were more pronounced when a combination of enzymes was used (Meng et al ., 2005). In another broiler study, soaking of barley for 24 h at room temperature with a commercial complex (with protease, xylanase and β -glucanase activity) reduced acid extract viscosity as well as soluble, insoluble and total β -glucan concentration in barley (Svihus et al ., 1997). Treatment of brewers ’ spent grain with xylanase for 3 h reduced the concentration of xylose and arabinose by 15% to 30% (Denstadli et al ., 2010). Inclusion of processed peas in the die ts reduced FI during the growing period, with birds fed enzymatically treated pea showing th e best FCR for the growing (days 2 2 to 35) and entire experimental period. Treatment of whole barley with a mixture of protease, xylanase and β -glucanase improved BWG and FCR in broiler chicks (Svihus et al ., 1997), whereas in anothe r study inclusion of enzymatical ly tre ated (with xylanase) brewers ’ spent grain i n broiler diets increa sed FI with no bene fi cial impact on BWG and FCR (Denstadli et al ., 2010). The observed FCR improvement in the enzymatically trea ted group might be due to the observed lower FI or/and the lower concentrations of ANF in the enzymatically treated peas as well as the degradation effect of supplemented enzymes on complex nutrients. In an experiment, Chen et al . (2009) investigated whether the bene fi cial effect of fermented feed on broiler growth performance was because of the probiotics per se or the fermentation process. Inclusion of probiotic, with similar micro fl ora population to the ferme nted feed, did not enhance growth perfo rmance as much as fermented feed did. The authors explained this observ ation by degradation effect of fermentation process on complex material and production of bene fi ci al substanc es for broiler gr owth and health. In th e present study, inclusio n of fermented pea in broiler diets did not improve growth perfo rmance an d nutrient digestibility. The total tract apparent digestibility of DM, ener gy and Ca were higher in broilers received SSF RSM than i n those fed native RSM (Chiang et al ., 2010). Chickens fed fermented SBM with Nutritional quality improvement of pea for broiler 1705 Aspergillus oryzae showed better FI, BWG and FCR compared with those received native SBM (Feng et al ., 2007). Broilers fed diets containing 10% fermented RSM (with L. fermentum , Enterococcus faecium , Saccharomyces cerevisae and B. subtilis ) had better BWG and FCR compared with those fed diets containing 10% native RSM (Chiang et al ., 2010). The BWG and FCR of broilers fed diets containing 15% fermented RSM were worse than those received feed co ntaining 0, 5 and 10% fer- mented RSM, while the other three groups (0%, 5% and 10%) were similar (Xu et al ., 2012). Th e in te ra ctio n betwe en ty pe of th e pea pro du cts a nd inc lus ion l ev el s of pe as wa s sig ni fi can t for AI D of sta rch . Inc rea sing in in clu sio n leve l of na tive p ea in b ro iler di ets form 10% to 30 % redu ced AID o f sta rc h. In agr eeme nt with th e pre sen t re su lt s, B re ne s et al . (1 993) and I gba sa n an d Gue nter (1 996) sh owe d that in clu sion of na t ive p ea in bro iler di ets re su lted in si gn i fi ca nt redu ctio n of i leal st ar ch di gestbili ty . This re duc tion in AI D of st arc h by in cre as in g in clu sio n le ve l wa s not obse rva bl e an ym or e wh en fe rmen ted an d enzym ati call y tr eat ed pea s we re use d in broi ler die ts. Th is mig ht be ex pla ined by th e red uc ti on of RS as we ll as s tarc h swel lin g a nd gel ati niz ati on th at mig ht hav e hap pe ned duri ng pro cess ing an d dryi ng. In a revi ew man usc rip t, it was dem ons tr at ed th at th e te mp erat ure thr esh ol d fo r th e sta bili zati on o f sta rch gelat ini zation ha s a negat ive corr ela tion with t he star ch hydr at ion (Ab doll ahi et al ., 20 13) . For in stan ce, a t exc ess wa ter co nten t (abo ve 4 0%), the s tar ch g ela tin iz ati on wa s sta bil ized at a te mpe ra tu re bet ween 50° C an d 70° C. Th is te mpe ratu re inc rea se d to abov e 10 0° C with < 35% w ater co nt ent ( Sv ih us et al ., 20 05 ). Pr oc essed pe as in the pre sen t stu dy were in cub at ed in a mois t con di tio n ( > 40 % wate r con ten t) an d we re dr ied usin g a rela tive ly m il d th er ma l and sh ea r t re at me nt s ( < 7 5°C fo r < 3 s ). The appl ie d pro duc ti on an d dry ing c ondi tio ns mi ght l ea d to st arc h swe llin g an d par tial gel ati niz ati on wh ich may h ave cau sed a lter ati on in sta rch dig esti bil ity. In the present study, the inclusion level of pea products had no remarkable effect on digestibility of AA. The observed increase in the AID of Thr, Lys and Met in the 30% inclusion group seemed to be only due to the higher levels of crystal- line Thr, Lys and Met in 30% inclusion diets. Furthermore, 30% inclusion group had lower FI and BWG compared with 10% inclusion group. It has been recommended that peas can be used up to 200 g/kg in broiler diet as a protein source with no negative impact on growth performance (Nalle et al ., 2011). In a review paper, the maximum inclusion level of 200 g/kg peas in broiler diets has been recommended (Castell et al ., 1996), while in another study the maximum inclusion level of 300 g/kg in broiler diets was suggested (Farrell et al ., 1999). Increase in inclusion levels of whole canola/pea mixture (0, 100, 200 or 300 g/kg) in broiler diets linearly declined BWG and curvilinearly FI, while the reduction in FI was most apparent at higher concentrations (Fasina and Campbell, 1997). It is a wel l-do cum en te d phen ome no n t hat th e G IT of br oi - ler s adap ts qui ckl y to the alt erat ion s i n diet s truc ture a nd com pos ition (S vihu s, 20 11 ). The low er rel ative o rgan we igh t of th e di ffer ent gu t sec ti on s in b oth pr oces sed p ea gr ou ps , par ticu larl y fo r bir ds fed enz ym ati ca lly tre ated pe a, coul d be ex pla ined by ob ser ve d re du ction in AN F, de gr ada tio n of com plex mate ria l and be tter ava ila bili ty of n utr ien ts in th e pro ces sed peas . It has be en re po rt ed tha t a dec reas e in ANF con ten t of fe ed c ou ld lea d to re duct ion i n dig esta vi sco sity , al te ra ti on in the gu t micr ob io ta and ch ange s in the mo rp ho- log y of the di ges tive tr act (S vih us et al ., 199 7; Bed fo rd an d Cow ies on, 2 01 2) . In ag reem ent wi th th e pres ent da ta, b ro il ers fe d enz yma tical ly tr eate d bar ley di et s had low er rel ati ve giz zar d and sm all inte sti ne we igh ts as wel l as simi lar rel ative cec um and pa nc re as we igh ts comp ared wi th bro ile rs fed nat ive b arl ey diet s (Svi hus et al ., 19 97 ). Gizz ard dev elo pm en t is di re ctl y relat ed to th e feed pa rtic le size . Fine fe ed part icl es in po ultr y di ets c oin cid e with gi zzar d unde r-de velo pmen t (S vi hu s, 20 11) . In th e pres ent stu dy , the U ltra -Rot or drye r mil l wh ich has be en used to d ry fe rm en te d and enz yma tica lly tr ea te d peas , si mu lta neo usly mi lled an d dri ed th e mat erial . Th er ef ore th e fi na l par ticle s iz es of the pr oc es se d pea s were con sid erab ly smal ler th an th e ini tia l par tic le siz e of th e gro und nat ive pe a wh ich ha s be en use d for p rod ucti on of th e pro ces sed pea s as wel l as the n ati ve pea di et s in the an imal tr ial . As the p arti cle si zes of wh eat, cor n and ot her fe ed ing redi ents u sed in bro iler di ets we re si mi la r, it ca n be specul ated t hat fi ne r part icl e sizes o f ferm ente d and en zym a- ti ca ll y trea ted pe as led to po or giz za rd deve lo pme nt. Fermentation and enzymatic treatment could improve the nutritional quality of pea by re duction in ANFs. Furthermore, taken into accou nt insigni fi cant interactions between type of the pea prod ucts and inclusion levels fo r variables measured (except for ileal starch digesti bility), it can be concluded that inclusion of e nzymatically treated pea in broiler diets cou ld improve broiler performa nce compared with other pea pro- ducts while, it showed neith er positive nor negative imp act on nutrients digestibility. H owever, the mode of action for feed ef fi ciency improvement by inclusion of enzymatically treated pea is not clear enough and needs to be studied further. The present fi ndings indicate the feasibility of these processes, particularly enzymatic treatment, for imp roving the nutritional quality of pea as a protein source for broiler nutrition. Acknowledgment This work has been funded by CORNET thro ugh AiF Projekt GmbH (106 EN/1 (OE142/13a)). 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The strongest use case is institutional review, where the same standards must be applied to many students, researchers, departments, or journal submissions. Plag.ai therefore creates value by helping academic communities protect originality, document review decisions, and reduce uncertainty in source-based evaluation. Review text similarity