Endogenous enzyme activities and tibia bone development of broiler chickens fed wheat-based diets supplemented with xylanase, [beta]-glucanase and phytase.
Wheat is an important energy source in poultry diets in many regions of the world, including Europe, Canada, Australia and New Zealand. However, the nutritive value of wheat is limited by its content of soluble non-starch polysaccharides (NSP), which are indigestible and impede the digestion of other nutrients. Like most grains, wheat also contains phytate, the main reservoir of phosphorus, which is not digested by birds due to their limited secretion of phytase . The exogenous enzymes that were used in this study, xylanase, [beta]-glucanase, and phytase, are now extensively used as additives in poultry diets and their physical effects are generally well understood, but the mechanisms behind their actions are still being researched. Research results to date have been used to determine or predict the optimum dose of xylanase and [beta]-glucanase enzymes in wheat- and barley-based diets and efforts have been made to set the same for phytase in maize-based diets . Although the efficacy of supplemental carbohydrases, proteases, and phytases in diets of poultry has been well established, there is still a great deal of uncertainty on the mechanisms of action of exogenous enzymes. Several factors can influence the response to combinations of enzymes, ranging from enzyme specificity to the target substrate, dosage, interactions between enzymes, ingredient quality, ingredient composition and age of animals. A number of mechanisms have been proposed to explain the useful effects of glucanase in improving energy and nutrient utilization of wheat-based diets . Possible mechanisms of action of carbohydrases in poultry diets include: improved access of endogenous enzymes to cell contents due to hydrolysis of cell wall arabinoxylans , reduction in viscosity and provision of prebiotics to stimulate a more beneficial microbiome. Additionally, they have been shown to augment the endogenous digestive enzymes in young animals. In addition to the use of the conventional xylanase, glucanase, phytase, and more recently, multicarbohydrase preparations, the application of normal digestive tract enzymes has also been proposed [5-8]. Several studies on the impact of nutrient restriction on leg abnormalities have concluded that the reduction in leg problems was mostly due to increased activity in birds at a critical stage in leg bone development [9,10]. Phytase improved the concentrations of Fe and Mg in broiler tibia bone but had no effect on Ca, P, and Zn contents , however, Shelton and Southern  found that the concentration of Zn in tibia was increased while Fe and Mn levels were not affected by dietary phytase. Other studies, [13,14] reported that phytase improved Zn utilization in broilers. Viveros et al  also found that phytase supplementation improved Ca, P, Mg and Zn retention in broilers at three and six weeks of age. Zyla et al  reported an improvement in gross performance and utilization of energy by chickens when phytase and xylanase were added to wheat-based diets. However, information on the effect of the impact of these enzymes and their combinations on broiler performance, energy utilization and nutrient digestibility is scarce. The present study was aimed at assessing the endogenous enzyme activities and tibia bone development of broiler chickens fed wheat-based diets supplemented with a combination of xylanase, [beta]-glucanase, and phytase.
MATERIALS AND METHODS
Experimental design and management of birds
This experiment was designed to investigate the effects of different levels of phytase, xylanase, and [beta]-glucanase supplements in diets fed to chickens between hatch and 10, 24, or 35 days. The enzyme products (Econase XT 25, Econase GT, and Quantum Blue) used were supplied by AB Vista, Marlborough, UK, while the wheat was obtained from local suppliers in New South Wales, Australia. A 3x2x2 factorial study was conducted using three levels of Quantum Blue; none, low (30 mg/kg) and a superdose (300 mg/kg), and none and optimum levels (100 mg/kg) of both Econase XT 25 and Econase GT. The ingredient and nutrient composition of the diets used are shown in Table 1. The basal diets were identical in ingredient profile and formulated to meet the nutrient specifications of broiler chickens as recommended by Aviagen . A total of 648 male day-old Ross 308 broiler chicks (initial weight, 40.45 [+ or -] 1.05 g) were randomly assigned to 12 treatments, each with six replicates (9 chickens per replicate). Birds were reared in multi-tiered brooder cages and raised in climate-controlled rooms at the Centre for Animal Research and Teaching, University of New England, Australia. Birds had ad libitum access to feed and water over the trial period. The initial brooding temperature was 33[degrees]C; this was gradually reduced to 24[degrees]C [+ or -] 1[degrees]C at 19 days of age and fixed at this level until the end of the experiment. Twenty-four hours of lighting were provided on the first day, then it was reduced to 23 h per day until day 3 after which 18 hours of light were delivered for the remainder of the experiment.
The leftover feed and birds were weighed at 35 days to measure the body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR). Feed intake, BWG and FCR data were corrected for mortality.
Digestive enzyme analyse
At d 10 and d 24 one bird was randomly selected from each cage, weighed, electrically stunned, killed by cervical dislocation and dissected to obtain 1 to 2 cm of the proximal part of the jejunum and the entire pancreas, which were used to measure the endogenous enzyme activities. Both the jejunum and pancreas were wrapped in labelled aluminum foil and snap-frozen in liquid nitrogen until they were transferred to a freezer storage room (-20[degrees]C) prior to analysis. The jejunum and pancreatic samples were processed according to the method described by Shirazi-Beechey et al  and Nitsan et al . Pancreatic and jejunal enzyme activities were measured by incubation with various substrate concentrations as standardized for poultry . The protein content of tissues and the activities of alkaline phosphatase, maltase, and sucrase were analyzed in the jejunal homogenate. The pancreatic tissue protein content and activities of trypsin and chymotrypsin amidase were assessed as previously described [21,22]. Protein concentrations in pancreatic and jejunal samples werp measuoed bo the Co omassie dye-binding procedure .
Apparent metabolizable energy
Excreta was collected into trays undernea each cage between 20 and 23 days. These were pooled per cage and used to determine the apparent metabolizable energy (AME). A sub-sample of excreta was analysed for Ti[O.sub.2] and gross energy (GE).
AME was then calculated as: AME = GEi-(GEox[Ti/To]), where GEi is the gross energy (MJ/kg) in feed, GEo is the gross energy (MJ/kg) in excreta, Ti is the concentration of titanium in the diets, and To is the concentration of titanium in the excreta.
Titanium dioxide analysis and ileal digestibility of nutrients
At d 24, two birds were randomly selected from each cage, weighed, electrically stunned, euthanazed using cervical dislocation and dissected. The ileal digesta was gently flushed with distilled water into plastic containers. Digesta samples from each cage were pooled together and then freeze-dried, ground (around 0.5 mm pore size) and stored in air-tight containers at -4[degrees]C before laboratory analysis. Both digesta and diet samples were analyzed for TiO2xxxxxx according to the method described by Short et al .
The apparent ileal nutrient digestibility percentage was calculated by the following formula using TiO2xxxxxx as the indigestible marker:
Digestibility % = 1 - Ti[O.sub.2Diet] x [N.sub.Digesta]/[N.sub.Digesta] x [N.sub.Diet] x 100
where [N.sub.Digesta] is the nutrient concentration in digesta (%), Ti[O.sub.2Digesta] is the titanium concentration in digesta (%), [N.sub.diet] is Nutrient concentration in diets(%) and Ti[O.sub.2] Diet is the titanium dioxide concentration in feeds(%).
Bone breaking strength
On d 35 the right drumstick was taken from two birds of each replicate and frozen at -20[degrees]C for bone strength analyses. The samples were defrosted and the tibia bone was extracted after adherent muscles, tissues, cartilage caps and fibula were removed manually. Breaking strength of the tibia bone was measured by positioning a 10 mm diameter compression rod against the bones and applying pressure (Lloyd, Hampshire, UK). Breaking strength was recorded as the force required to break the bone and was measured in the range of 0 to 500 N. The entire bones were then dried for 12 h at 105[degrees]C in a forced-air convection oven (Qualtex Universal Series 2000, Watson Victor Ltd, Perth, Australia) and ashed (550[degrees]C for 4 h) in a Carbolite CWF 1200 chamber furnace (Carbolite, Sheffield, UK). The ashed samples were ground and stored at 4 [degrees]C in airtight plastic containers for dry matter (DM) and mineral content analyses.
The Animal Ethics Committee of the University of New England, Australia approved the study (approval number AEC15-080).
The data were statistically analysed using the general linear model procedure of Minitab version 17 software program . Tukey's test was used to compare mean values for significant differences at the p<5% level of probability.
Results of FI, BWG, and FCR between one and 35 days of age are shown in Table 2. There was an interaction (p<0.03) between phytase and [beta]-glucanase, which improved the FCR from hatch to 35 d. Feed intake was decreased (p<0.001) with supplementation of optimum level of xylanase. From one to 35 d, birds fed the low dose of phytase had higher BWG compared to the other groups. Supplementing diets with optimum dose of xylanase improved (p = 0.05) BWG during 1 to 35 d. The addition of optimum level of xylanase between one and 35 d resulted in a better (p<0.001) FCR than the control.
Endogenous enzyme activities
Chymotrypsin activity at d 10 was improved (p<0.01) due to an interaction between the three enzyme products. Protein content at d 10 improved (p<0.001) with addition of phytase while general proteolytic activity (GPA) (p<0.02) and lipase activity (p<0.001) decreased with addition of phytase (Table 3). The pancreatic protein content and enzyme activities at d 24 are shown in Table 4. There were increments in protein content (p<0.01) and lipase activity (p<0.04) with supplementation of superdose level of phytase. On the other hand, increasing the supplemented led phytase resulted in a decrease in chymotrypsin (p<0.02), trypsin (p<0.01), and GPA (p<0.001). The optimum dose of xylanase also decreased the chymotrypsin activity (p = 0.05), while optimum level of [beta]-glucanase increased the GPA (p<0.001).
Jejunal enzyme activities at 10 and 24 d of age are presented in Table 5 and 6, respectively. Phytase superdose improved maltase (p = 0.05), sucrase (p<0.001), and alkaline phosphatase (p<0.001) activities at 10 d of age while the low level of phytase addition increased aminopeptidase activity (p<0.005). At d 24, protein content (p<0.001) of the jejunual mucosa and activity of sucrase (p<0.04) were increased by phytase supplementation while maltase activity (p<0.001) was reduced. Aminopeptidase activity peaked (p<0.001) at the low level of phytase. No effects of interactions were observed.
Apparent metabolizable energy and nutrient digestibility
An interaction (p<0.01) between phytase, xylanase and [beta]-glucanase resulted to an improvement in gross energy digestibility. There was an interaction (p<0.01) between phytase and [beta]-glucanase, which resulted in increased starch digestibility. Apparent metabolizable energy increased (p<0.01) when diets were augmented with each of the enzymes, irrespective of the dosage administered (Table 7). There was an improvement in crude protein digestibility with addition of phytase (p<0.001) and optimum level of [beta]-glucanase (p< 0.003), but this was not significant (p>0.05) with xylanase.
Breaking strength and mineral contents of tibia bone
Table 8 shows the effects of the test enzymes on bone strength. Tibia bone breaking strength increased with addition of doses of phytase (p<0.001) and at optimum level of [beta]-glucanase (p<0.04). Bone DM content decreased (p<0.04) when diets were supplemented with phytase. There was no significant in mineral contents of tibia bone.
The results showed that the gross performance of broiler chickens was affected by the test enzyme supplements between one and 35 days. This observation could be attributed to the combined action of phytase on phytic acid and xylanase on the xylans as well as the breakdown of glucans by [beta]-glucanase. These enzyme interactions help to increase the digestibility of nutrients in young birds as they lack these enzymes, with a resultant increase in feed conversion. This result has been demonstrated by Peng et al  who reported an increase in FI by xylanase supplementation during 1 to 3 weeks of age but the effect was reduced during 4 to 6 weeks. It is well known that phytate negatively affects protein availability and absorption of some minerals , and increases mucus production  thereby, reducing broiler performance. The use of phytase in broiler diets to degrade phytate and thus release phosphorus and certain other nutrients and improve productivity is a common practice in commercial broiler production . The current results confirm the benefit of feeding a superdose level of phytase as the performance is significantly better than that of those birds fed the low or more conventional levels of phytase.
Endogenous enzyme activities
Phytase supplementation increased the pancreatic protein content and chymotrypsin activity but reduced lipase activity at d 10 while at d 24 this observation changed to a reduction in chymotrypsin activity, an increase in lipase, GPA and total protein content especially with the superdose level of phytase. Increased levels of chymotrypsin at d 10 of age may be reflecting improved gastric digestion due to the reduction of phytate inhibition, enabling greater through-flow of protein and hence a greater demand for pancreatic enzymes. At 24 d of age this effect was reversed, possibly because a larger pancreas is more able to cope and the need for chymotrypsin is no longer the bottleneck when gastric and small intestinal proteolysis is eased with superdose phytase. Fuente et al  reported that viscosity of the intestinal contents determined with 30-d-old chickens was negatively related to endogenous [beta]-glucanase activity. The inverse effects on lipase is interesting and may reflect differential changes in the lipolytic capacity of the bird.
Jejunal enzyme activities seem generally to increase with high phytase supplementation in particular at d 10 but this effect is largely lost at d 24 with the exception of sucrase activity. According to Pinheiro et al  a complex enzymes supplementation had an through an interaction effect resulted in improved enzyme activity and nutrient digestibility immediately after a feed restriction period from 7 to 14 d. There is marked effects of phytase superdosing on jejunal alkaline phosphatase at 10 d. This enzyme plays a critical role in intestinal integrity and reduction of inflammatory responses. Further, it is thought to dephosphorylate myo-inositol monophosphate ([IP.sub.1]) , the end product of phytase activity, which might explain why it is so responsive to phytase superdosing. If [IP.sub.1], as a substrate, induces alkaline phosphatase activity then this may partly explain the performance benefits noted with superdosing phytase. Reports of studies on endogenous enzyme activities in broilers fed wheat-based diets supplemented with phytase are limited. However, the change may be a reflection of an impact on endogenous enzymes. The test enzymes tended to accentuate rather than reduce the activities of the endogenous enzymes. It is difficult to compare the present study to previous studies because this study used different doses of carbohydrases and phytase and there is a need to do more research in this area.
Apparent metabolizable energy and nutrient digestibility
Apparent metabolizable energy improved with supplementation of phytase, xylanase, and [beta]-glucanase. The action of these enzymes on anti-nutrients such as NSP, phytic acid, and other factors, although not directly measured, might be the main reason behind the improvement in the AME and the fact that these were independent main effects suggests they are additive and possibly working through different mechanisms. This result agree with the finding of Wu et al  who observed that the use of phytase and xylanase increased the AME and digestibility of nutrients in wheat-based diets for broilers. [beta]-Glucanase was also shown to improve the AME in this study. It is noteworthy that the effect of phytase was considerably larger than that of either the xylanase or [beta]-glucanase alone. Bedford  reported that large influxes of digestive enzymes, bile acids, lecithin and lysozyme are a challenge to gut microbes such that the duodenum is largely devoid of bacteria.
Phytase addition improved protein digestibility, as has been previously reported [2,34] who indicated that adding phytase to broiler diets improves the digestibility of protein and amino acids. The positive effect of xylanase on protein digestibility has also been reported . Individual effects of xylanase on starch digestibility and all three enzymes on gross energy were observed in this study. Ravindran et al  reported that energy digestibility was improved by dietary phytase supplementation, while Liu et al  demonstrated that adding xylanase to wheat-based diets reduced the intestinal mucosal viscosity and improved the digestibility of energy and starch in broiler chickens. [beta]-Glucanase has been observed to improve energy and starch digestibility when supplemented alone or combined with xylanase and/or phytase to wheat and barley-based diets [33, 37, 38].
In the current study, more than two interactions were noticed between the three test enzymes on digestibility of arginine, threonine, leucine, and lysine. Phytase and [beta]-glucanase supplementation increased the digestibility of almost all the measured amino acids but the benefit of the phytase was markedly greater. These results are in line with the improvement in protein digestibility, which was previously highlighted. It has been shown that phytate-protein bonds are insoluble and less responsive to proteolytic enzymes than protein alone . This binding could reduce the solubility and therefore, digestibility of proteins and amino acids.
Bone breaking strength and mineral content of tibia bone
Tibia bone breaking strength was improved with the addition of phytase or [beta]-glucanase. The test enzymes had no effect on the mineral contents of the bones in the present study, suggesting that the beneficial effect on breaking strength may be due to change in bone matrix rather than mineralisation. It has been reported that adding phytase to broiler chicken diets results in a marked improvement in the utilization of phytate phosphorus as measured by bone ash, and bone strength . Bone density is considered to reflect bone mineral content. However, many recent studies have shown that the mineral density can be contingent upon the chemical organic matrix of bones .
The test microbial enzymes (phytase, xylanase, and [beta]-glucanase) in wheat-based diets especially at superdose level in the case of phytase, improved the utilization of several enzyme activities that was assessed in the present study. Furthermore, supplementation of phytase, xylanase, and [beta]-glucanase improved gross performance, possibly through increased nutrient digestibility as well as improved breaking strength of the tibia bone. The inclusion of a superdose level of phytase has even more benefits, although the economics of use of such a dose has not been evaluated.
Submitted Nov 15, 2019; Revised Jan 14, 2020; Accepted Mar 26, 2020
CONFLICT OF INTEREST
We certify that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript. Bedford MR is an employee of AB Vista.
The first author acknowledges the Saudi Arabian government for providing a scholarship. We are grateful to AB Vista, UK for providing research funds. We also express our sincere gratitude to the staff of Centre for Animal Research and Teaching (CART), University of New England, Australia for helping with the management of chickens during the study period.
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Mohammed Al-Qahtani (1,2) * Emmanuel Uchenna Ahiwe (1), Medani Eldow Abdallh (1), Edwin Peter Chang'a (1), Harriet Gausi (1), Michael R Bedford (3), and Paul Ade Iji (1, 4) *
* Corresponding Authors:
Mohammed Al-Qahtani Tel: +61-424820161, Fax: +61-2-6773-2769, E-mail: email@example.com
Paul Ade Iji Tel: +679-9927767, Fax: +679-3400275, E-mail: firstname.lastname@example.org
(1) School of Environmental and Rural Sciences, University of New England, Armidale, New South Wales 2351, Australia
(2) Ministry of Education, Riyadh, 12435, Saudi Arabia
(3) AB Vista, 3 Woodstock Court, Marlborough, Wiltshire SN8 4AN, UK
(4) College of Agriculture, Fisheries and Forestry, Fiji National University, P.O. Box 1544, Nausori, Fiji
Mohammed Al-Qahtani https://orcid.org/0000-0001-7317-1319
Emmanuel Uchenna Ahiwe https://orcid.org/0000-0001-9862-7503
Medani Eldow Abdallh https://orcid.org/0000-0002-8419-5057
Edwin Peter Chang'a https://orcid.org/0000-0002-8978-6921
Harriet Gausi https://orcid.org/0000-0002-2625-8371
Michael R Bedford https://orcid.org/0000-0002-5308-4290
Paul Ade Iji https://orcid.org/0000-0002-6981-6281
Table 1. Ingredient and nutrient composition of diets fed Items Starter (1) Grower (1) Finisher (1) Ingredient composition (%) Wheat 60.45 64.13 68.28 Soybean meal 29.41 22.78 19.53 Meat and bone meal 3.001 5.00 4.00 Canola oil 3.58 4.50 5.49 Limestone 0.941 0.66 0.73 Dicalcium phosphate 1.16 0.54 0.70 Salt 0.111 0.08 0.10 Na bicar (b) 0.20 0.20 0.2 TiO2xxxxxx 0.001 0.50 0.00 Vit-mineral premix (2) 0.20 0.20 0.20 Choline Cl 70% 0.051 0.05 0.05 L-lysine 0.33 0.86 0.29 DL-methionine 0.361 0.32 0.28 L-threonine 0.21 0.18 0.15 Total 100 100 100 Nutrient composition (%) ME (MJ/kg) 12.55 12.97 13.40 Crude protein 23.00 21.50 19.50 Crude fat 5.511 6.55 7.47 Crude fibre 2.49 2.41 2.37 Arginine 1.37 1.23 1.09 Lysine 1.28 1.17 1.02 Methionine 0.651 0.58 0.52 Methionine+cysteine 0.95 0.87 0.80 Tryptophan 0.261 0.23 0.21 Isoleucine 0.911 0.82 0.75 Threonine 0.86 0.77 0.68 Valine 1.01 0.93 0.85 Calcium 0.96 0.87 0.84 Available P 0.481 0.43 0.39 Sodium 0.161 0.16 0.16 Potassium 0.941 0.82 0.74 Chlorine 0.211 0.31 0.20 Choline (mg/kg) 1,700 1,600 1,500 Linoleic 1.71 1.92 2.17 ME, metabolizable energy. (1) Starter, grower, and finisher were each one are 12 treatments 3 levels of phytase, 2 levels of both xylanase and [beta]-glucanase. (2) The active ingredients contained in the vitamin-mineral premix were as follows (per kg of diet): vitamin A 12,000 IU, vitamin D3 3,500 IU, vitamin E 30.0 mg, vitamin xxxxxxK3 2.0 mg, thiamine 2 mg, riboflavin6mg,pyridoxine 5 mg, vitamin xxxxxxB12 0.02 mg, niacin 50 mg, pantothenate 12 mg, biotin 0[beta]01 mg, folic acid 2 mg, Fe 60 mg, Zn 60 mg,Mn 80 mg,Cu 8mg,Se 0[beta]1 mg, Mo 1 mg, Co 0[beta]3 mg, I 1 mg.
Table 2. Gross response of birds on diets containing different levels of phytase, xylanase, and [beta]-glucanase fed between hatch and 35 d of age Enzymes levels FI (kg/bird) Phytase Xylanase [beta]-glucanase 1-35 d None None None 3.56 Optimum None 3.33 None Optimum 3.57 Optimum Optimum 3.36 Low None None 3.62 Optimum None 3.54 None Optimum 3.62 Optimum Optimum 3.45 Superdose None None 3.55 Optimum None 3.34 None Optimum 3.54 Optimum Optimum 3.46 SEM 24.60 Main effects None 3.46 Low 3.56 Superdose 3.47 None 3.58 (a) Optimum 3.41 (b) None 3.49 Optimum 3.50 Source of variation Phytase 0.17 Xylanase 0.001 [beta]-glucanase 0.85 Phytase x xylanase 0.71 Phytase x 0.64 [beta]-glucanase Xylanase x 0.84 [beta]-glucanase Phytase x xylanase x 0.65 [beta]-glucanase Enzymes levels BWG (kg/b) Phytase Xylanase [beta]-glucanase 1-35 d None None None 2.37 Optimum None 2.41 None Optimum 2.43 Optimum Optimum 2.43 Low None None 2.47 Optimum None 2.51 None Optimum 2.48 Optimum Optimum 2.59 Superdose None None 2.51 Optimum None 2.53 None Optimum 2.39 Optimum Optimum 2.53 SEM 15.20 Main effects None 2.41 (b) Low 2.51 (a) Superdose 2.49 (ab) None 2.44 (b) Optimum 2.50 (a) None 2.47 Optimum 2.47 Source of variation Phytase 0.02 Xylanase 0.05 [beta]-glucanase 0.82 Phytase x xylanase 0.62 Phytase x 0.29 [beta]-glucanase Xylanase x 0.38 [beta]-glucanase Phytase x xylanase x 0.46 [beta]-glucanase Enzymes levels FCR Phytase Xylanase [beta]-glucanase 1-35 d None None None 1.50 (a) Optimum None 1.38 (abc) None Optimum 1.47 (ab) Optimum Optimum 1.39 (abc) Low None None 1.46 (ab) Optimum None 1.41 (abc) None Optimum 1.46 (ab) Optimum Optimum 1.33 (c) Superdose None None 1.42 (abc) Optimum None 1.32 (c) None Optimum 1.48 (ab) Optimum Optimum 1.37 (bc) SEM 0.009 Main effects None 1.43 Low 1.42 Superdose 1.40 None 1.46 (a) Optimum 1.37 (b) None 1.42 Optimum 1.42 Source of variation Phytase 0.13 Xylanase 0.001 [beta]-glucanase 0.98 Phytase x xylanase 0.93 Phytase x 0.03 [beta]-glucanase Xylanase x 0.53 [beta]-glucanase Phytase x xylanase x 0.27 [beta]-glucanase Values are means of 6 replicates (9 birds from each cage). FI, feed intake; BWG, body weight gain; FCR, feed conversion ratio (kg feed:kg body weight gain); SEM, standard error of means. (a-c) Mean values with different superscripts within the columns are different (p<0.05).
Table 3. Effect of diets containing different levels of phytase, xylanase, and [beta]-glucanase on pancreatic protein concentration (mg/g tissue) and enzyme activities ([micro]mol/mg protein/min) (10 days of age) Phytase levels Xylanase [beta]- Protein ChymoT levels glucanase levels None None None 88.3 3.10 (b) Optimum None 84.2 4.00 (ab) None Optimum 80.0 4.30 (a) Optimum Optimum 88.4 2.80 (b) Low None None 107.5 4.00 (ab) Optimum None 107.0 3.30 (ab) None Optimum 108.4 3.20 (ab) Optimum Optimum 106.1 4.30 (a) Superdose None None 104.7 4.70 (a) Optimum None 99.3 4.30 (a) None Optimum 109.8 4.20 (a) Optimum Optimum 114.7 4.70 (a) SEM 1.93 0.14 Main effects None 85.2 (b) 3.50 (b) Low 107.3 (a) 3.70 (ab) Superdose 107.1 (a) 4.40 (a) None 99.8 3.90 Optimum 100.0 3.90 None 98.5 3.90 Optimum 101.3 3.90 Source of variation Phytase 0.001 0.02 Xylanase 0.96 0.95 [beta]-Glucanase 0.38 0.92 Phytase x xylanase 0.89 0.71 Phytase x 0.22 0.97 [beta]-glucanase Xylanase x 0.26 0.85 [beta]-glucanase Phytase x 0.59 0.01 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- Trypsin GPA levels glucanase levels None None None 3.80 0.75 Optimum None 4.00 0.77 None Optimum 4.20 0.87 Optimum Optimum 4.00 0.70 Low None None 3.80 0.70 Optimum None 3.10 0.68 None Optimum 3.20 0.70 Optimum Optimum 3.60 0.70 Superdose None None 4.20 0.77 Optimum None 4.10 0.74 None Optimum 4.10 0.74 Optimum Optimum 3.6 0.75 SEM 0.12 0.01 Main effects None 4.00 0.77 (a) Low 3.50 0.70 (b) Superdose 4.00 0.75 (ab) None 3.90 0.75 Optimum 3.80 0.73 None 3.80 0.74 Optimum 3.80 0.74 Source of variation Phytase 0.10 0.02 Xylanase 0.56 0.19 [beta]-Glucanase 0.87 0.72 Phytase x xylanase 0.95 0.30 Phytase x 0.65 0.83 [beta]-glucanase Xylanase x 0.86 0.34 [beta]-glucanase Phytase x 0.37 0.08 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- Lipase levels glucanase levels None None None 7.20 Optimum None 7.50 None Optimum 7.70 Optimum Optimum 6.80 Low None None 6.30 Optimum None 5.90 None Optimum 6.20 Optimum Optimum 6.80 Superdose None None 5.30 Optimum None 5.50 None Optimum 5.80 Optimum Optimum 5.40 SEM 0.13 Main effects None 7.30 (a) Low 6.30 (b) Superdose 5.50 (c) None 6.40 Optimum 6.30 None 6.30 Optimum 6.50 Source of variation Phytase 0.001 Xylanase 0.59 [beta]-Glucanase 0.38 Phytase x xylanase 0.72 Phytase x 0.44 [beta]-glucanase Xylanase x 0.41 [beta]-glucanase Phytase x 0.06 xylanase x [beta]-glucanase Values are means of 6 replicates (one bird per cage). ChymoT, chymotrypsin; GPA, general proteolytic activity; SEM, standard error of means. (a-c) Mean values with different superscripts within the columns are different (p<0.05).
Table 4. Effect of diets containing different levels of phytase, xylanase, and [beta]-glucanase on pancreatic protein concentration (mg/g tissue) and enzyme activities (pmol/mg protein/min) (24 days of age) Phytase levels Xylanase [beta]- Protein ChymoT levels glucanase levels None None None 122.5 3.20 Optimum None 99.9 2.70 None Optimum 94.1 3.10 Optimum Optimum 101.8 2.40 Low None None 112.1 2.30 Optimum None 105.2 2.60 None Optimum 109.1 3.20 Optimum Optimum 111.1 2.40 Superdose None None 121.7 2.40 Optimum None 135.3 2.20 None Optimum 132.5 2.30 Optimum Optimum 126.1 2.10 SEM 2.68 0.09 Main effects None 104.6 (b) 2.90 (a) Low 109.4 (b) 2.60 (ab) Superdose 128.9 (a) 2.30 (b) None 115.3 2.80 (a) Optimum 113.2 2.40 (b) None 116.1 2.60 Optimum 112.5 2.60 Source of variation Phytase 0.001 0.02 Xylanase 0.67 0.05 [beta]-Glucanase 0.45 0.84 Phytase x xylanase 0.65 0.64 Phytase x 0.38 0.42 [beta]-glucanase Xylanase x 0.51 0.26 [beta]-glucanase Phytase x 0.11 0.34 Phytase levels Xylanase [beta]- Trypsin GPA levels glucanase levels None None None 3.10 0.52 Optimum None 3.10 0.54 None Optimum 2.80 0.60 Optimum Optimum 2.40 0.60 Low None None 2.20 0.50 Optimum None 2.70 0.50 None Optimum 2.90 0.57 Optimum Optimum 2.20 0.56 Superdose None None 2.40 0.50 Optimum None 2.20 0.48 None Optimum 2.50 0.49 Optimum Optimum 2.30 0.51 SEM 0.08 0.08 Main effects None 2.90 (a) 0.56 (a) Low 2.50 (ab) 0.53 (ab) Superdose 2.40 (b) 0.49 (b) None 2.70 0.53 Optimum 2.50 0.53 None 2.60 0.51 (b) Optimum 2.5 0.55 (a) Source of variation Phytase 0.01 0.001 Xylanase 0.28 0.81 [beta]-Glucanase 0.52 0.001 Phytase x xylanase 0.97 0.89 Phytase x 0.14 0.22 [beta]-glucanase Xylanase x 0.10 0.93 [beta]-glucanase Phytase x 0.19 0.58 Phytase levels Xylanase [beta]- Lipase levels glucanase levels None None None 4.40 Optimum None 4.20 None Optimum 4.30 Optimum Optimum 4.30 Low None None 4.20 Optimum None 4.10 None Optimum 4.40 Optimum Optimum 4.50 Superdose None None 5.20 Optimum None 4.50 None Optimum 5.10 Optimum Optimum 4.50 SEM 0.09 Main effects None 4.30 (b) Low 4.30 (b) Superdose 4.80 (a) None 4.60 Optimum 4.40 None 4.40 Optimum 4.50 Source of variation Phytase 0.04 Xylanase 0.19 [beta]-Glucanase 0.69 Phytase x xylanase 0.47 Phytase x 0.70 [beta]-glucanase Xylanase x 0.64 [beta]-glucanase Phytase x 1.00 xylanase x [beta]-glucanase Values are means of 6 replicates (one bird per cage). ChymoT, chymotrypsin; GPA, general proteolytic activity; SEM, standard error of means. (a, b) Mean values with different superscripts within the columns are different (p<0.05).
Table 5. Effect of diets containing different levels of phytase, xylanase, and [beta]-glucanase on jejunual protein concentration (mg/g tissue) and enzyme activities (pmol/mg protein/min) in jejunum (10 days of age) Phytase levels Xylanase [beta]- Protein Maltase levels glucanase levels None None None 53.9 0.68 Optimum None 56.0 0.72 None Optimum 53.8 0.66 Optimum Optimum 53.4 0.79 Low None None 53.7 0.79 Optimum None 51.7 0.80 None Optimum 60.5 0.71 Optimum Optimum 54.8 0.86 Superdose None None 58.9 0.82 Optimum None 55.8 0.80 None Optimum 55.6 0.85 Optimum Optimum 57.2 0.79 SEM 1.21 0.02 Main effects None 54.3 0.72 (b) Low 55.2 0.79 (b) Superdose 56.9 0.82 (a) None 56.1 0.75 Optimum 54.8 0.79 None 55.0 0.77 Optimum 55.9 0.78 Source of variation Phytase 0.70 0.05 Xylanase 0.63 0.26 [beta]-Glucanase 0.73 0.82 Phytase x xylanase 0.74 0.24 Phytase x 0.53 0.90 [beta]-glucanase Xylanase x 0.92 0.37 [beta]-glucanase Phytase x 0.77 0.51 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- Sucrase AP levels glucanase levels None None None 0.06 0.56 Optimum None 0.07 0.59 None Optimum 0.06 0.56 Optimum Optimum 0.07 0.59 Low None None 0.09 0.70 Optimum None 0.11 0.73 None Optimum 0.08 0.57 Optimum Optimum 0.10 0.80 Superdose None None 0.10 0.74 Optimum None 0.11 0.86 None Optimum 0.13 0.89 Optimum Optimum 0.10 0.79 SEM 0.004 0.03 Main effects None 0.07 (c) 0.58 (b) Low 0.09 (b) 0.70 (ab) Superdose 0.11 (a) 0.82 (a) None 0.09 0.67 Optimum 0.09 0.73 None 0.90 0.70 Optimum 0.90 0.70 Source of variation Phytase 0.001 0.001 Xylanase 0.23 0.27 [beta]-Glucanase 0.93 0.93 Phytase x xylanase 0.10 0.54 Phytase x 0.28 0.86 [beta]-glucanase Xylanase x 0.15 0.97 [beta]-glucanase Phytase x 0.26 0.23 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- APP levels glucanase levels None None None 4.10 Optimum None 3.40 None Optimum 3.60 Optimum Optimum 4.00 Low None None 4.80 Optimum None 4.50 None Optimum 3.80 Optimum Optimum 4.60 Superdose None None 3.70 Optimum None 3.80 None Optimum 3.70 Optimum Optimum 3.70 SEM 0.10 Main effects None 3.80 (b) Low 4.40 (a) Superdose 3.70 (b) None 4.00 Optimum 4.00 None 4.00 Optimum 3.9 Source of variation Phytase 0.005 Xylanase 0.92 [beta]-Glucanase 0.46 Phytase x xylanase 0.79 Phytase x 0.51 [beta]-glucanase Xylanase x 0.08 [beta]-glucanase Phytase x 0.35 xylanase x [beta]-glucanase Values are means of 6 replicates (one bird per cage). AP alkaline phosphatase; APP aminopeptidase; SEM, standard error of means. (a-c) Mean values with different superscripts within the columns are different (p<0.05).
Table 6. Effect of diets containing different levels of phytase, xylanase, and [beta]-glucanase on jejunual protein concentration (mg/g tissue) and enzyme activities ([micro]mol/mg protein/min) in jejunum (24 days of age) Phytase levels Xylanase [beta]- Protein Maltase levels Glucanase levels None None None 83.3 0.56 Optimum None 93.2 0.61 None Optimum 89.2 0.65 Optimum Optimum 83.7 0.58 Low None None 87.5 0.59 Optimum None 84.6 0.53 None Optimum 88.2 0.60 Optimum Optimum 81.7 0.60 Superdose None None 111.5 0.50 Optimum None 113.3 0.48 None Optimum 122.6 0.46 Optimum Optimum 111.4 0.48 SEM 2.97 0.01 Main effects None 87.4 (b) 0.60 (a) Low 85.5 (b) 0.58 (a) Superdose 114.7 (a) 0.48 (b) None 97.0 0.56 Optimum 94.6 0.55 None 95.6 0.54 Optimum 96.1 0.56 Source of variation Phytase 0.001 0.001 Xylanase 0.66 0.53 [beta]-Glucanase 0.92 0.42 Phytase x xylanase 0.83 0.83 Phytase x 0.87 0.54 [beta]-glucanase Xylanase x 0.33 0.73 [beta]-glucanase Phytase x 0.90 0.20 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- Sucrase AP levels Glucanase levels None None None 0.06 0.26 Optimum None 0.05 0.19 None Optimum 0.05 0.25 Optimum Optimum 0.06 0.26 Low None None 0.06 0.25 Optimum None 0.06 0.29 None Optimum 0.06 0.25 Optimum Optimum 0.06 0.29 Superdose None None 0.06 0.21 Optimum None 0.06 0.22 None Optimum 0.06 0.24 Optimum Optimum 0.06 0.25 SEM 0.001 0.01 Main effects None 0.05 (b) 0.24 Low 0.06 (a) 0.27 Superdose 0.06 (ab) 0.23 None 0.06 0.24 Optimum 0.06 0.25 None 0.06 0.24 Optimum 0.06 0.26 Source of variation Phytase 0.04 0.38 Xylanase 0.67 0.83 [beta]-Glucanase 0.86 0.37 Phytase x xylanase 0.98 0.49 Phytase x 0.87 0.86 [beta]-glucanase Xylanase x 0.30 0.67 [beta]-glucanase Phytase x 0.56 0.75 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- APP levels Glucanase levels None None None 1.25 Optimum None 1.13 None Optimum 1.24 Optimum Optimum 1.19 Low None None 1.44 Optimum None 1.27 None Optimum 1.36 Optimum Optimum 1.39 Superdose None None 1.10 Optimum None 1.02 None Optimum 1.03 Optimum Optimum 1.11 SEM 0.03 Main effects None 1.20 (b) Low 1.37 (a) Superdose 1.06 (b) None 1.24 Optimum 1.18 None 1.20 Optimum 1.22 Source of variation Phytase 0.001 Xylanase 0.29 [beta]-Glucanase 0.68 Phytase x xylanase 0.77 Phytase x 0.99 [beta]-glucanase Xylanase x 0.16 [beta]-glucanase Phytase x 0.88 xylanase x [beta]-glucanase Values are means of 6 replicates (one bird per cage). AR alkaline phosphatase; APR aminopeptidase; SEM, standard error of means. (a, b) Mean values with different superscripts within the columns are different (p<0.05).
Table 7. Apparent metabolizable energy and ileal nutrient digestibility of birds on diets supplemented with different levels of phytase, xylanase, and [beta]-glucanase (24 days of age) Phytase levels Xylanase [beta]- AME Protein levels Glucanase levels None None None 13.51 81.07 Optimum None 13.73 80.09 None Optimum 13.96 82.70 Optimum Optimum 14.00 82.14 Low None None 14.10 82.60 Optimum None 14.14 84.83 None Optimum 14.26 86.04 Optimum Optimum 14.44 85.21 Superdose None None 14.96 86.37 Optimum None 15.02 88.24 None Optimum 15.06 87.92 Optimum Optimum 15.40 87.69 SEM 0.07 0.40 Main effects None 13.80 (c) 81.50 (c) Low 14.23 (b) 84.67 (b) Superdose 15.11 (a) 87.55 (a) None 14.30 (b) 84.45 Optimum 14.46 (a) 84.70 None 14.25 (b) 83.87 (b) Optimum 14.51 (a) 85.28 (a) Source of variation Phytase 0.001 0.001 Xylanase 0.01 0.58 [beta]-Glucanase 0.001 0.003 Phytase x xylanase 0.70 0.29 Phytase x 0.58 0.36 [beta]-glucanase Xylanase x 0.57 0.09 [beta]-glucanase Phytase x 0.33 0.28 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- GE Starch levels Glucanase levels None None None 76.54 (d) 95.75 (ab) Optimum None 75.36 (d) 94.95 (ab) None Optimum 77.07 (d) 95.26 (ab) Optimum Optimum 81.19 (bc) 95.97 (ab) Low None None 76.49 (d) 94.24 (b) Optimum None 81.25 (bc) 95.07 (ab) None Optimum 82.67 (abc) 96.69 (a) Optimum Optimum 81.68 (abc) 96.34 (ab) Superdose None None 81.11 (c) 96.93 (a) Optimum None 85.79 (a) 96.93 (a) None Optimum 84.48 (ab) 96.89 (a) Optimum Optimum 84.89 (a) 96.79 (a) SEM 1.00 1.00 Main effects None 77.54 (c) 95.48 (b) Low 80.52 (b) 95.59 (b) Superdose 83.79 (a) 96.89 (a) None 79.73 (b) 95.96 Optimum 81.51 (a) 96.01 None 79.24 (b) 95.64 (b) Optimum 82.00 (a) 96.32 (a) Source of variation Phytase 0.001 0.001 Xylanase 0.001 0.86 [beta]-Glucanase 0.001 0.01 Phytase x xylanase 0.85 0.87 Phytase x 0.23 0.01 [beta]-glucanase Xylanase x 0.13 0.89 [beta]-glucanase Phytase x 0.001 0.10 xylanase x [beta]-glucanase Values are means of 6 replicates (2 birds from each cage) and for AME (8 birds from each cage). AME, apparent metabolizable energy; GE, gross energy; SEM, standard error of means. (a-d) Mean values with different superscripts within the columns are different (p<0.05).
Table 8. Breaking strength and mineral contents of tibia bone on 35-day old chicks fed wheat-based diets supplemented with phytase, xylanase, and [beta]-glucanase Phytase levels Xylanase [beta]- BreakStr levels glucanase (kg/[mm.sup.2]) levels None None None 330.0 Optimum None 361.0 None Optimum 361.0 Optimum Optimum 391.5 Low None None 377.2 Optimum None 402.3 None Optimum 405.3 Optimum Optimum 408.8 Superdose None None 396.9 Optimum None 405.3 None Optimum 406.9 Optimum Optimum 412.7 SEM 5.06 Main effects None 360.9 (b) Low 398.4 (a) Superdose 405.6 (a) None 379.6 Optimum 397.0 None 378.9 (b) Optimum 397.7 (a) Source of variation Phytase 0.001 Xylanase 0.06 [beta]-Glucanase 0.04 Phytase x xylanase 0.56 Phytase x 0.80 [beta]-glucanase Xylanase x 0.64 [beta]-glucanase Phytase x 0.87 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- DM (%) Ash (%) levels glucanase levels None None None 69.6 49.7 Optimum None 68.8 49.4 None Optimum 70.0 49.5 Optimum Optimum 68.9 49.8 Low None None 67.8 49.5 Optimum None 66.1 50.0 None Optimum 67.2 49.4 Optimum Optimum 66.5 49.6 Superdose None None 68.7 49.4 Optimum None 66.1 49.7 None Optimum 66.9 50.1 Optimum Optimum 65.6 49.9 SEM 0.44 0.08 Main effects None 69.3 (a) 49.6 Low 66.9 (b) 49.6 Superdose 66.8 (b) 49.8 None 68.4 49.6 Optimum 67.0 49.7 None 67.8 49.6 Optimum 67.5 49.7 Source of variation Phytase 0.04 0.57 Xylanase 0.13 0.44 [beta]-Glucanase 0.70 0.48 Phytase x xylanase 0.89 0.51 Phytase x 0.80 0.24 [beta]-glucanase Xylanase x 0.71 0.98 [beta]-glucanase Phytase x 0.93 0.35 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- Ca (%) P (%) levels glucanase levels None None None 37.2 16.5 Optimum None 37.6 16.6 None Optimum 37.2 16.5 Optimum Optimum 37.1 16.4 Low None None 37.4 16.6 Optimum None 37.5 16.6 None Optimum 37.1 16.4 Optimum Optimum 36.9 16.4 Superdose None None 36.8 16.1 Optimum None 37.2 16.5 None Optimum 37.2 16.6 Optimum Optimum 36.7 16.3 SEM 0.11 0.05 Main effects None 37.3 16.5 Low 37.2 16.5 Superdose 37.0 16.4 None 37.1 16.5 Optimum 37.2 16.5 None 37.3 16.5 Optimum 37.0 16.4 Source of variation Phytase 0.54 0.72 Xylanase 0.94 0.98 [beta]-Glucanase 0.30 0.73 Phytase x xylanase 0.93 0.99 Phytase x 0.71 0.41 [beta]-glucanase Xylanase x 0.21 0.21 [beta]-glucanase Phytase x 0.83 0.42 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- Mg (%) K (%) levels glucanase levels None None None 0.81 0.59 Optimum None 0.82 0.59 None Optimum 0.80 0.61 Optimum Optimum 0.81 0.57 Low None None 0.84 0.56 Optimum None 0.83 0.60 None Optimum 0.81 0.55 Optimum Optimum 0.80 0.59 Superdose None None 0.81 0.57 Optimum None 0.82 0.60 None Optimum 0.83 0.61 Optimum Optimum 0.82 0.61 SEM 0.003 0.01 Main effects None 0.81 0.59 Low 0.82 0.58 Superdose 0.82 0.60 None 0.82 0.58 Optimum 0.82 0.59 None 0.82 0.58 Optimum 0.81 0.59 Source of variation Phytase 0.41 0.58 Xylanase 0.91 0.43 [beta]-Glucanase 0.09 0.74 Phytase x xylanase 0.43 0.27 Phytase x 0.15 0.63 [beta]-glucanase Xylanase x 0.49 0.59 [beta]-glucanase Phytase x 0.76 0.88 xylanase x [beta]-glucanase Phytase levels Xylanase [beta]- S (%) levels glucanase levels None None None 0.24 Optimum None 0.23 None Optimum 0.24 Optimum Optimum 0.26 Low None None 0.26 Optimum None 0.24 None Optimum 0.25 Optimum Optimum 0.25 Superdose None None 0.26 Optimum None 0.27 None Optimum 0.24 Optimum Optimum 0.26 SEM 0.004 Main effects None 0.24 Low 0.25 Superdose 0.26 None 0.25 Optimum 0.25 None 0.25 Optimum 0.25 Source of variation Phytase 0.41 Xylanase 0.48 [beta]-Glucanase 0.89 Phytase x xylanase 0.52 Phytase x 0.32 [beta]-glucanase Xylanase x 0.22 [beta]-glucanase Phytase x 0.99 xylanase x [beta]-glucanase Values are means of 6 replicates (2 birds per cage). BreakStr, Breaking strength; DM, dry matter; SEM, standard error of means. (a, b) Mean values with different superscripts within the columns are different (p<0.05).
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|Author:||Qahtani, Mohammed Al-; Ahiwe, Emmanuel Uchenna; Abdallh, Medani Eldow; Chang'a, Edwin Peter; Gausi,|
|Date:||Jun 1, 2021|
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