This article was downloaded by: [Memorial University of Newfoundland] On: 01 August 2014, At: 10:19 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Effects of exogenous xylanase on performance, nutrient digestibility, volatile fatty acid production and digestive tract thermal profiles of broilers fed on wheat- or maize-based diet a
b
H.V. Masey-O’neill , M. Singh & A.J. Cowieson
b
a
Research and Development Department, AB Vista Feed Ingredients, Marlborough SN8 4AN, UK b
Poultry Research Foundation, University of Sydney, Camden NSW 2570, Australia Accepted author version posted online: 03 Mar 2014.Published online: 29 Apr 2014.
To cite this article: H.V. Masey-O’neill, M. Singh & A.J. Cowieson (2014) Effects of exogenous xylanase on performance, nutrient digestibility, volatile fatty acid production and digestive tract thermal profiles of broilers fed on wheat- or maizebased diet, British Poultry Science, 55:3, 351-359, DOI: 10.1080/00071668.2014.898836 To link to this article: http://dx.doi.org/10.1080/00071668.2014.898836
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
British Poultry Science, 2014 Vol. 55, No. 3, 351–359, http://dx.doi.org/10.1080/00071668.2014.898836
Effects of exogenous xylanase on performance, nutrient digestibility, volatile fatty acid production and digestive tract thermal profiles of broilers fed on wheat- or maize-based diet H.V. MASEY-O’NEILL, M. SINGH1,
AND
A.J. COWIESON1
Downloaded by [Memorial University of Newfoundland] at 10:19 01 August 2014
Research and Development Department, AB Vista Feed Ingredients, Marlborough SN8 4AN, UK, and 1Poultry Research Foundation, University of Sydney, Camden NSW 2570, Australia
Abstract 1. A previous experiment reported that caecal temperature was negatively correlated with d 49 feed conversion ratio (FCR). This increased temperature in the caeca may indicate a prebiotic effect. An experiment was designed to investigate whether caecal temperature was affected in diets based on maize and whether other portions of the tract were affected. 2. A total of 25 Ross 308-d-old male broilers were allocated to each of 8 replicate pens per treatment. Treatments followed a 2 × 3 factorial design: two diets based on wheat or maize and three levels of enzyme addition, 0, 16 000 or 32 000 BXU/kg. Growth performance was assessed between d 1 and 49. Digestibility measurements were taken at d 28 and 49. On d 49, the excised small and large intestine of each bird was thermally imaged, weighed and volatile fatty acids (VFA) measured. 3. On d 28 and d 49, birds on the maize diets had higher feed intake and weight gain than those offered wheat diets. Additionally, on d 28, birds that received the maize diet had lower FCR than those offered the wheat diet. Enzyme improved FCR at d 49, independently of cereal. On d 28, enzyme improved the coefficient of apparent ileal DM digestibility and the coefficient of apparent ileal nitrogen digestibility. Enzyme only improved apparent ileal digestible energy in wheat-based diets (interactive term). On d 49, all digestibility parameters were improved by enzyme. Enzyme increased gizzard weight in maize-fed birds and the caeca of those fed wheat were heavier. The higher enzyme dose decreased duodenal temperature. In summary of VFA data, wheat-based diets produced more total VFAs and the total amount also increased with enzyme. 4. It appears from this study that there is equal potential in both wheat and maize diets for xylanase to improve performance of broilers probably through different mechanisms.
INTRODUCTION In recent years, the inclusion of exogenous xylanase in maize-based diets for non-ruminants has increased, due in part to increasing energy costs and a subsequent attempt to improve nutrient utilisation in such diets. This is a move away from the traditional use in viscous diets, based on wheat for example, where the aim is viscosity reduction. However, use of such enzymes in maize-based diets is still effective even though viscosity may not be a major nutritional obstacle. Many authors have reported positive benefits in
performance of broilers fed on maize-based diets (Zanella et al., 1999; Cowieson et al., 2010) and diets based on non-viscous wheat (Persia et al., 2002). There is suggestion for a cell wall dissolution mechanism (Meng and Slominski, 2005) and the authors have previously shown in vitro dissolution of maize cell wall material (Masey O’Neill et al., 2014). However, there is also evidence for a microbiota-mediated effect (Choct et al., 1996). A prebiotic is defined as a material that stimulates beneficial and health-promoting bacteria in the gut, such as bifidobacteria. Often they are polysaccharides not digested in the proximal digestive
Correspondence to: H.V. Masey-O’Neill, AB Vista Feed Ingredients, Marlborough, SN 8 4AN, UK. E-mail: helen.maseyo’[email protected] Accepted for publication 8 January 2014.
© 2014 British Poultry Science Ltd
Downloaded by [Memorial University of Newfoundland] at 10:19 01 August 2014
352
H.V. MASEY-O’NEILL ET AL.
tract. Xylo-oligosaccharides (XOS), the products of xylan digestion by xylanases, have been shown to act as prebiotic in many species (Lecerf et al., 2012), including broilers (Courtin et al., 2008). The stimulation of such species will likely decrease pathogenic species (Kim et al., 2011), possibly decrease post-prandial inflammation (Lecerf et al., 2012) but may also increase short chain volatile fatty acid production (Madhukumar and Muralikrishna, 2012). Such fatty acids have been reported to stimulate gut hormone release (such as peptide-YY, PYY; Goodlad et al., 1987; Longo et al., 1991) and this has also been shown in response to xylanase (Singh et al., 2012). The gut hormone PYY has been shown to delay gastric emptying (Savage et al., 1987) in a so-called ileal brake effect. Presumably, these combined effects improve the microbiological environment, increase digestibility of nutrients and therefore improve animal performance. It is possible that this occurs in vivo when xylo-oligosaccharides are produced in situ as a product of endogenous xylanase included in the feed. In investigating this mechanism, the authors have shown that the temperature of the caeca of broilers fed on wheat-based diets increased with the use of xylanase (Cowieson and Masey O’Neill, 2013). Furthermore, temperature of the caeca was significantly negatively correlated with d 49 feed conversion ratio (FCR) (P < 0.05). Increased temperature in the caeca may indicate a prebiotic effect as outlined above. Xylanases may be expected to exert a greater effect in wheat-based diets, therefore the question arose as to whether caecal temperature was also affected by diets based on other cereals and whether other portions of the tract were similarly or oppositely affected.
MATERIALS AND METHODS All experimental procedures conducted in this study were in accordance with the University of Sydney Animal Ethics Committee and with the Australian code for the care and use of animals for scientific purposes.
Enzymes The xylanase used in the current study was supplied by AB Vista Feed Ingredients (Marlborough, UK). This xylanase preparation (Econase XT) contained 160 000 units of endo-1,4-β-xylanase activity (EC 3.2.1.8) per g. One unit of xylanase (XU) is defined as the amount of enzyme that liberates 1 nmol reducing sugars from birchwood xylan, measured as xylose equivalents, under the conditions of the assay (AB Enzymes, Germany).
Experimental details A total of 1200 Ross 308-d-old male broilers were obtained from a commercial hatchery, weighed and randomly allocated to one of 6 dietary treatments in a completely randomised design. Each treatment was replicated 8 times with 25 chicks per replicate pen. Broilers were kept at a temperature of 31°C for d 1–4 and thereafter this was reduced by 0.5°C/d to 24°C. The lighting regime for the study consisted of 23L:1D for the first 4 d and then 18L:6D for the remainder of the experiment. On d 28, three birds per pen were randomly selected, killed with sodium pentobarbitone injection via the wing vein and the contents of the distal half of the ileum were collected (the ileum being defined as the portion of the small intestine from Meckel’s diverticulum to the ileo-caecal junction). Ileal contents were immediately frozen at –18ºC prior to being freeze-dried and ground to pass a 0.5 mm screen. On d 49, further three birds per pen were randomly selected. Each bird in turn was killed with injection of sodium pentobarbitone administered via the wing vein. Within 30 s of death, the excised small and large intestine both caeca of each bird were imaged using an FLIR T620 Thermal Imaging Camera (FLIR Systems AB, Germany). Thermal images were processed using FLIR ThermaCAM Researcher Pro 2.10 software (FLIR Systems AB, Germany). The process of thermal imaging is described by Cowieson and Masey O’Neill (2013). The empty proventriculus, gizzard, entire small intestine and the caeca were weighed individually for two birds chosen randomly from each pen at d 49. Diets Diets were based on wheat and soya bean meal or maize and soya bean meal and were formulated to be nutritionally adequate in all essential nutrients (Table 1). Treatments were arranged as a three (level of enzyme, 0, 16 000 or 32 000 BXU per kg) by two (diet base, maize or wheat) factorial in a completely randomised block design. Treatments are described in Table 2. Starter diets were offered from d 1 to d 14, grower from d 15 to d 28 and the finisher from d 29 to d 49. Feed and water were available ad libitum. All diets were steam pelleted at 80ºC in a Palmer pellet mill with a steam pressure of 150 kDa and a 7 s conditioner residence time. Acid insoluble ash (as Celite; AIA) was used at 20 g/kg as an indigestible marker. Chemical analyses The gross energy (GE) of diets and lyophilised digesta were determined using a Parr 1281
XYLANASE IN WHEAT AND MAIZE DIETS
Table 1.
Ingredient composition and calculated analysis (g/kg air dry basis) of the control diets Starter
Downloaded by [Memorial University of Newfoundland] at 10:19 01 August 2014
353
Grower
Finisher
Wheat
Maize
Wheat
Maize
Wheat
Maize
Wheat Maize SBM48 Soya oil NaCl NaHCO3 DL Met Lysine HCl L Thr CaCO3 DCP Vitamins and minerals1
629.5 – 294.9 33.9 2.0 3.3 2.70 4.0 0.90 11.0 15.8 2.0
– 601.1 348.9 9.50 2.8 2.6 2.3 2.5 0.00 9.0 9.3 2.0
680.0 – 247.5 39.1 2.0 2.2 2.4 1.4 1.0 2.0 0.4 2.0
672.8 283.3 10.0 2.4 2.0 2.3 0.7 0.4 10.5 13.5 2.0
728.8 – 193.5 46.3 1.6 2.0 2.0 2.0 1.1 12.0 8.8 2.0
– 721.3 231.9 15.1 2.3 1.5 1.8 1.2 0.4 9.8 2.9 2.0
Calculated provision AME, MJ/kg CP, g/kg Ca, g/kg Dig. P, g/kg Dig. Lys, g/kg Dig. Met, g/kg Dig. Cys, g/kg Dig. Thr, g/kg Na, g/kg DEB, meq/kg
12.54 214.6 9.0 4.6 12.5 5.2 3.3 7.7 2.0 242
12.54 221.8 9.0 4.6 12.5 5.2 3.0 7.7 2.0 257
12.85 194.6 8.0 3.6 9.5 4.7 3.1 7.0 1.7 220
12.85 194.7 8.0 3.4 9.6 4.9 3.0 7.1 1.7 229
13.17 174.2 7.5 3.3 8.6 4.1 2.9 6.3 1.5 190
13.17 174.2 7.5 3.3 8.6 4.2 2.7 6.3 1.5 196
AIA was added over-the-top at 20 g/kg to all diets as an indigestible marker, thus diluting all nutrients equally. SBM48, soya bean meal, 48% CP; DCP, dicalcium phosphate. 1 Provided the following per kg diet: ethoxyquin, 100 mg; biotin, 0.2 mg; calcium pantothenate, 12.8 mg; cholecalciferol, 60 μg; cyanocobalamin, 0.017 mg; folic acid, 5.2 mg; menadione, 4 mg; niacin, 35 mg; pyridoxine, 10 mg; trans-retinol, 3.33 mg; riboflavin, 12 mg; thiamine, 3.0 mg; dl-α-tocopheryl acetate, 60 mg; choline chloride, 638 mg; Co, 0.3 mg; Cu, 3 mg; Fe, 25 mg; I, 1 mg; Mn, 125 mg; Mo, 0.5 mg; Se, 200 μg; Zn, 60 mg.
formula using the insoluble marker ratio in the diet and the ileal digesta.
Table 2. Details of experimental diets Treatment ID 1 2 3 4 5 6
Diet base1
Enzyme2
Dose (U/kg feed)
Wheat Wheat Wheat Maize Maize Maize
None Xylanase Xylanase None Xylanase Xylanase
NA 16 000 32 000 NA 16 000 32 000
1
Xylanase = Econase XT 25 (160000 BXU/g) See Table 1 above
2
adiabatic bomb calorimeter (Parr Instrument Company, Moline, IL, USA) that was standardised with benzoic acid. Nitrogen concentration of samples was determined by the Dumas method using a FP-428 nitrogen analyser (LECO® Corporation, St. Joseph, MI, USA) as described by Sweeney (1989). The acid insoluble ash component of dried diets and ileal digesta samples were determined according to the method of Siriwan et al. (1993).
Apparent ileal digestibility coefficient NT NT AIA d AIA i ¼ NT AIA d
where ðNT=AIA Þd is the ratio of nutrient and insoluble marker in the diet and ðNT=AIA Þi is the ratio of nutrient and insoluble marker in the ileal digesta.
Data analysis All data were exported to JMP v. 9.0 (SAS Institute, Cary, NC, USA) and subjected to analysis of variance. Means were separated by Tukey’s LSD and were considered significant at P < 0.05.
RESULTS Performance
Calculations The apparent ileal digestibility coefficient of N and energy were calculated by the following
Mortality in the trial was
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Effects of exogenous xylanase on performance, nutrient digestibility, volatile fatty acid production and digestive tract thermal profiles of broilers fed on wheat- or maize-based diet a
b
H.V. Masey-O’neill , M. Singh & A.J. Cowieson
b
a
Research and Development Department, AB Vista Feed Ingredients, Marlborough SN8 4AN, UK b
Poultry Research Foundation, University of Sydney, Camden NSW 2570, Australia Accepted author version posted online: 03 Mar 2014.Published online: 29 Apr 2014.
To cite this article: H.V. Masey-O’neill, M. Singh & A.J. Cowieson (2014) Effects of exogenous xylanase on performance, nutrient digestibility, volatile fatty acid production and digestive tract thermal profiles of broilers fed on wheat- or maizebased diet, British Poultry Science, 55:3, 351-359, DOI: 10.1080/00071668.2014.898836 To link to this article: http://dx.doi.org/10.1080/00071668.2014.898836
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
British Poultry Science, 2014 Vol. 55, No. 3, 351–359, http://dx.doi.org/10.1080/00071668.2014.898836
Effects of exogenous xylanase on performance, nutrient digestibility, volatile fatty acid production and digestive tract thermal profiles of broilers fed on wheat- or maize-based diet H.V. MASEY-O’NEILL, M. SINGH1,
AND
A.J. COWIESON1
Downloaded by [Memorial University of Newfoundland] at 10:19 01 August 2014
Research and Development Department, AB Vista Feed Ingredients, Marlborough SN8 4AN, UK, and 1Poultry Research Foundation, University of Sydney, Camden NSW 2570, Australia
Abstract 1. A previous experiment reported that caecal temperature was negatively correlated with d 49 feed conversion ratio (FCR). This increased temperature in the caeca may indicate a prebiotic effect. An experiment was designed to investigate whether caecal temperature was affected in diets based on maize and whether other portions of the tract were affected. 2. A total of 25 Ross 308-d-old male broilers were allocated to each of 8 replicate pens per treatment. Treatments followed a 2 × 3 factorial design: two diets based on wheat or maize and three levels of enzyme addition, 0, 16 000 or 32 000 BXU/kg. Growth performance was assessed between d 1 and 49. Digestibility measurements were taken at d 28 and 49. On d 49, the excised small and large intestine of each bird was thermally imaged, weighed and volatile fatty acids (VFA) measured. 3. On d 28 and d 49, birds on the maize diets had higher feed intake and weight gain than those offered wheat diets. Additionally, on d 28, birds that received the maize diet had lower FCR than those offered the wheat diet. Enzyme improved FCR at d 49, independently of cereal. On d 28, enzyme improved the coefficient of apparent ileal DM digestibility and the coefficient of apparent ileal nitrogen digestibility. Enzyme only improved apparent ileal digestible energy in wheat-based diets (interactive term). On d 49, all digestibility parameters were improved by enzyme. Enzyme increased gizzard weight in maize-fed birds and the caeca of those fed wheat were heavier. The higher enzyme dose decreased duodenal temperature. In summary of VFA data, wheat-based diets produced more total VFAs and the total amount also increased with enzyme. 4. It appears from this study that there is equal potential in both wheat and maize diets for xylanase to improve performance of broilers probably through different mechanisms.
INTRODUCTION In recent years, the inclusion of exogenous xylanase in maize-based diets for non-ruminants has increased, due in part to increasing energy costs and a subsequent attempt to improve nutrient utilisation in such diets. This is a move away from the traditional use in viscous diets, based on wheat for example, where the aim is viscosity reduction. However, use of such enzymes in maize-based diets is still effective even though viscosity may not be a major nutritional obstacle. Many authors have reported positive benefits in
performance of broilers fed on maize-based diets (Zanella et al., 1999; Cowieson et al., 2010) and diets based on non-viscous wheat (Persia et al., 2002). There is suggestion for a cell wall dissolution mechanism (Meng and Slominski, 2005) and the authors have previously shown in vitro dissolution of maize cell wall material (Masey O’Neill et al., 2014). However, there is also evidence for a microbiota-mediated effect (Choct et al., 1996). A prebiotic is defined as a material that stimulates beneficial and health-promoting bacteria in the gut, such as bifidobacteria. Often they are polysaccharides not digested in the proximal digestive
Correspondence to: H.V. Masey-O’Neill, AB Vista Feed Ingredients, Marlborough, SN 8 4AN, UK. E-mail: helen.maseyo’[email protected] Accepted for publication 8 January 2014.
© 2014 British Poultry Science Ltd
Downloaded by [Memorial University of Newfoundland] at 10:19 01 August 2014
352
H.V. MASEY-O’NEILL ET AL.
tract. Xylo-oligosaccharides (XOS), the products of xylan digestion by xylanases, have been shown to act as prebiotic in many species (Lecerf et al., 2012), including broilers (Courtin et al., 2008). The stimulation of such species will likely decrease pathogenic species (Kim et al., 2011), possibly decrease post-prandial inflammation (Lecerf et al., 2012) but may also increase short chain volatile fatty acid production (Madhukumar and Muralikrishna, 2012). Such fatty acids have been reported to stimulate gut hormone release (such as peptide-YY, PYY; Goodlad et al., 1987; Longo et al., 1991) and this has also been shown in response to xylanase (Singh et al., 2012). The gut hormone PYY has been shown to delay gastric emptying (Savage et al., 1987) in a so-called ileal brake effect. Presumably, these combined effects improve the microbiological environment, increase digestibility of nutrients and therefore improve animal performance. It is possible that this occurs in vivo when xylo-oligosaccharides are produced in situ as a product of endogenous xylanase included in the feed. In investigating this mechanism, the authors have shown that the temperature of the caeca of broilers fed on wheat-based diets increased with the use of xylanase (Cowieson and Masey O’Neill, 2013). Furthermore, temperature of the caeca was significantly negatively correlated with d 49 feed conversion ratio (FCR) (P < 0.05). Increased temperature in the caeca may indicate a prebiotic effect as outlined above. Xylanases may be expected to exert a greater effect in wheat-based diets, therefore the question arose as to whether caecal temperature was also affected by diets based on other cereals and whether other portions of the tract were similarly or oppositely affected.
MATERIALS AND METHODS All experimental procedures conducted in this study were in accordance with the University of Sydney Animal Ethics Committee and with the Australian code for the care and use of animals for scientific purposes.
Enzymes The xylanase used in the current study was supplied by AB Vista Feed Ingredients (Marlborough, UK). This xylanase preparation (Econase XT) contained 160 000 units of endo-1,4-β-xylanase activity (EC 3.2.1.8) per g. One unit of xylanase (XU) is defined as the amount of enzyme that liberates 1 nmol reducing sugars from birchwood xylan, measured as xylose equivalents, under the conditions of the assay (AB Enzymes, Germany).
Experimental details A total of 1200 Ross 308-d-old male broilers were obtained from a commercial hatchery, weighed and randomly allocated to one of 6 dietary treatments in a completely randomised design. Each treatment was replicated 8 times with 25 chicks per replicate pen. Broilers were kept at a temperature of 31°C for d 1–4 and thereafter this was reduced by 0.5°C/d to 24°C. The lighting regime for the study consisted of 23L:1D for the first 4 d and then 18L:6D for the remainder of the experiment. On d 28, three birds per pen were randomly selected, killed with sodium pentobarbitone injection via the wing vein and the contents of the distal half of the ileum were collected (the ileum being defined as the portion of the small intestine from Meckel’s diverticulum to the ileo-caecal junction). Ileal contents were immediately frozen at –18ºC prior to being freeze-dried and ground to pass a 0.5 mm screen. On d 49, further three birds per pen were randomly selected. Each bird in turn was killed with injection of sodium pentobarbitone administered via the wing vein. Within 30 s of death, the excised small and large intestine both caeca of each bird were imaged using an FLIR T620 Thermal Imaging Camera (FLIR Systems AB, Germany). Thermal images were processed using FLIR ThermaCAM Researcher Pro 2.10 software (FLIR Systems AB, Germany). The process of thermal imaging is described by Cowieson and Masey O’Neill (2013). The empty proventriculus, gizzard, entire small intestine and the caeca were weighed individually for two birds chosen randomly from each pen at d 49. Diets Diets were based on wheat and soya bean meal or maize and soya bean meal and were formulated to be nutritionally adequate in all essential nutrients (Table 1). Treatments were arranged as a three (level of enzyme, 0, 16 000 or 32 000 BXU per kg) by two (diet base, maize or wheat) factorial in a completely randomised block design. Treatments are described in Table 2. Starter diets were offered from d 1 to d 14, grower from d 15 to d 28 and the finisher from d 29 to d 49. Feed and water were available ad libitum. All diets were steam pelleted at 80ºC in a Palmer pellet mill with a steam pressure of 150 kDa and a 7 s conditioner residence time. Acid insoluble ash (as Celite; AIA) was used at 20 g/kg as an indigestible marker. Chemical analyses The gross energy (GE) of diets and lyophilised digesta were determined using a Parr 1281
XYLANASE IN WHEAT AND MAIZE DIETS
Table 1.
Ingredient composition and calculated analysis (g/kg air dry basis) of the control diets Starter
Downloaded by [Memorial University of Newfoundland] at 10:19 01 August 2014
353
Grower
Finisher
Wheat
Maize
Wheat
Maize
Wheat
Maize
Wheat Maize SBM48 Soya oil NaCl NaHCO3 DL Met Lysine HCl L Thr CaCO3 DCP Vitamins and minerals1
629.5 – 294.9 33.9 2.0 3.3 2.70 4.0 0.90 11.0 15.8 2.0
– 601.1 348.9 9.50 2.8 2.6 2.3 2.5 0.00 9.0 9.3 2.0
680.0 – 247.5 39.1 2.0 2.2 2.4 1.4 1.0 2.0 0.4 2.0
672.8 283.3 10.0 2.4 2.0 2.3 0.7 0.4 10.5 13.5 2.0
728.8 – 193.5 46.3 1.6 2.0 2.0 2.0 1.1 12.0 8.8 2.0
– 721.3 231.9 15.1 2.3 1.5 1.8 1.2 0.4 9.8 2.9 2.0
Calculated provision AME, MJ/kg CP, g/kg Ca, g/kg Dig. P, g/kg Dig. Lys, g/kg Dig. Met, g/kg Dig. Cys, g/kg Dig. Thr, g/kg Na, g/kg DEB, meq/kg
12.54 214.6 9.0 4.6 12.5 5.2 3.3 7.7 2.0 242
12.54 221.8 9.0 4.6 12.5 5.2 3.0 7.7 2.0 257
12.85 194.6 8.0 3.6 9.5 4.7 3.1 7.0 1.7 220
12.85 194.7 8.0 3.4 9.6 4.9 3.0 7.1 1.7 229
13.17 174.2 7.5 3.3 8.6 4.1 2.9 6.3 1.5 190
13.17 174.2 7.5 3.3 8.6 4.2 2.7 6.3 1.5 196
AIA was added over-the-top at 20 g/kg to all diets as an indigestible marker, thus diluting all nutrients equally. SBM48, soya bean meal, 48% CP; DCP, dicalcium phosphate. 1 Provided the following per kg diet: ethoxyquin, 100 mg; biotin, 0.2 mg; calcium pantothenate, 12.8 mg; cholecalciferol, 60 μg; cyanocobalamin, 0.017 mg; folic acid, 5.2 mg; menadione, 4 mg; niacin, 35 mg; pyridoxine, 10 mg; trans-retinol, 3.33 mg; riboflavin, 12 mg; thiamine, 3.0 mg; dl-α-tocopheryl acetate, 60 mg; choline chloride, 638 mg; Co, 0.3 mg; Cu, 3 mg; Fe, 25 mg; I, 1 mg; Mn, 125 mg; Mo, 0.5 mg; Se, 200 μg; Zn, 60 mg.
formula using the insoluble marker ratio in the diet and the ileal digesta.
Table 2. Details of experimental diets Treatment ID 1 2 3 4 5 6
Diet base1
Enzyme2
Dose (U/kg feed)
Wheat Wheat Wheat Maize Maize Maize
None Xylanase Xylanase None Xylanase Xylanase
NA 16 000 32 000 NA 16 000 32 000
1
Xylanase = Econase XT 25 (160000 BXU/g) See Table 1 above
2
adiabatic bomb calorimeter (Parr Instrument Company, Moline, IL, USA) that was standardised with benzoic acid. Nitrogen concentration of samples was determined by the Dumas method using a FP-428 nitrogen analyser (LECO® Corporation, St. Joseph, MI, USA) as described by Sweeney (1989). The acid insoluble ash component of dried diets and ileal digesta samples were determined according to the method of Siriwan et al. (1993).
Apparent ileal digestibility coefficient NT NT AIA d AIA i ¼ NT AIA d
where ðNT=AIA Þd is the ratio of nutrient and insoluble marker in the diet and ðNT=AIA Þi is the ratio of nutrient and insoluble marker in the ileal digesta.
Data analysis All data were exported to JMP v. 9.0 (SAS Institute, Cary, NC, USA) and subjected to analysis of variance. Means were separated by Tukey’s LSD and were considered significant at P < 0.05.
RESULTS Performance
Calculations The apparent ileal digestibility coefficient of N and energy were calculated by the following
Mortality in the trial was
