This article was downloaded by: [OARE Consortium] On: 07 July 2015, At: 03:39 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: 5 Howick Place, London, SW1P 1WG
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Subsequent growth performance and digestive physiology of broilers fed on starter diets containing spray-dried porcine plasma as a substitute for meat meal a
a
a
S.S.M. Beski , R.A. Swick & P.A. Iji a
School of Environmental and Rural Sciences, University of New England, Armidale, NSW 2351, Australia Accepted author version posted online: 01 Jul 2015.
Click for updates To cite this article: S.S.M. Beski, R.A. Swick & P.A. Iji (2015): Subsequent growth performance and digestive physiology of broilers fed on starter diets containing spray-dried porcine plasma as a substitute for meat meal, British Poultry Science, DOI: 10.1080/00071668.2015.1068429 To link to this article: http://dx.doi.org/10.1080/00071668.2015.1068429
Disclaimer: This is a version of an unedited manuscript that has been accepted for publication. As a service to authors and researchers we are providing this version of the accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to this version also.
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
1 Publisher: Taylor & Francis & British Poultry Science Ltd Journal: British Poultry Science DOI: 10.1080/00071668.2015.1068429
CBPS-2015-067
an us cr ip t
Subsequent growth performance and digestive physiology of broilers fed on starter diets
M
containing spray-dried porcine plasma as a substitute for meat meal
ed
S.S.M. BESKI, R.A. SWICK AND P.A. IJI
School of Environmental and Rural Sciences, University of New England, Armidale, NSW
pt
2351, Australia
ce
Running title: High quality proteins in starter diets
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
Ed. Kjaer, May 2015; MacLeod, June 2015
Correspondence to: Paul Iji, School of Environmental and Rural Sciences, University of New England, Armidale, NSW 2351, Australia. Email: [email protected] Phone: +61 2 67732082.
Accepted for publication 14th May 2015
2
Abstract. 1. A 4 x 2 factorial experiment was conducted to investigate the effect of inclusion of spray-dried porcine plasma (SDPP), in lieu of meat meal, in the starter diet on performance and digestive physiology of broiler chickens between hatch and 35 d of age. Four levels of SDPP (0, 5, 10 or 20 g/kg) were included in the starter diets in lieu of meat meal on either wheat- or maize-based diets.
an us cr ip t
2. Over the first 10 d, and throughout the 35 d experimental period, birds gained more body
weight with increasing concentrations of SDPP regardless to the type of grain used. Inclusion
35 d study. There was no significant effect of the type of grain and its interaction with SDPP on the body weight gain and feed per gain for the two assessed periods.
3. At d 10, the relative weight of the gizzard+proventriculus, spleen and liver increased with increasing concentrations of SDPP.
M
4. At d 24 of age the grain and SDPP inclusion significantly interacted, depressing the weight
ed
of bursa and spleen in birds that received the highest concentration of SDPP in the maizebased diet. Birds fed on the maize-based diets had higher relative weight of pancreas than
pt
those on the wheat-based diets.
5. Increasing concentrations of SDPP in the starter diet improved the activities of maltase,
ce
sucrase and alkaline phosphatase at 24 d of age. The interaction of grain and SDPP concentration was significant for sucrase activity in birds on the wheat-based diets. Chickens
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
of SDPP in the starter diet markedly improved feed per gain in the starter phase and across the
on maize-based diets had higher alkaline phosphatase and maltase activities than those on
wheat-based diets 6. Chicks that were offered SDPP-containing starter diets had longer villi, deeper crypts and lower villi/crypt than the control at d 24 of age regardless of the grain type used. Furthermore, longer villi and larger villi/crypt were found in chicken groups fed on wheat-based diets than those on maize-based diets.
3
7. Chickens on maize-based diets had higher dressing percentage and relative breast weight than those on wheat-based diets at d 35 of age.
8. It can be concluded that supplementation of starter diets with SDPP would be beneficial to the long-term growth of broiler chickens. The effect of the basal grain used in the diet is minimal.
an us cr ip t
INTRODUCTION
It is widely accepted that nutritional supplements given in the immediate post-hatch period
growth and overall development of chicks (Henderson et al., 2008). Broiler chicks have been shown to benefit from immediate access to feed. Although the focus of early nutrition has
been on the provision of energy, chicks benefit from a more balanced nutrient profile,
M
particularly containing amino acids. Blood products such as spray-dried whole blood, plasma
or red cells have been documented as a source of proteins with a good amino acid profile and
ed
digestibility, and have been used as ingredients in farm animal diets for many years (Castelló et al., 2004). Careful handling of the raw materials and utilisation of the spray-dried process
pt
have dramatically improved the quality and subsequent use of blood protein products in farm
ce
animal diets (Campbell, 1998). Spray-dried porcine plasma (SDPP) and similar products have been used by the pig industry to support piglets prior to and after weaning (Kats et al., 1994; Coffey and Cromwell, 2001; Van Dijk et al., 2001). As a high-quality animal protein source
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
help in the development of the digestive system, which improves the nutrient utilisation,
with an adequate supply of essential amino acids, SDPP increases diet palatability (Ermer et al., 1994) and improves immuno-competence (Coffey and Cromwell, 1995), and is usually considered to be an essential ingredient in the diet of early weaned pigs (Thacker, 1999). Positive effects have been observed in many studies due to the incorporation of porcine blood by-products, particularly SDPP, in the diets of piglets. These effects include improvement in development of the immune system, antibody functions, inflammatory
4
response and changes in intestinal morphology (Owusu-Asiedu et al., 2002; Rodriguez et al., 2007; Campbell et al., 2009; Moretó and Pérez-Bosque, 2009), small intestinal growth and activation of insulin-like growth factors (De Rodas et al., 1995; Jiang et al., 2000), and performance improvement (Mazurkiewicz et al., 1990; Pierce et al., 2005; Nofrarias et al., 2006). These results have increased the interest in the application of this high quality protein
an us cr ip t
product in the poultry industry too and particularly in the starter phase. The objective of this
study is to evaluate the effect of SDPP inclusion, as a substitute for meat meal, in starter diet
that was tested is that SDPP would support better growth response than meat meal, regardless of the dietary grain base.
MATERIAL AND METHODS
M
Animal ethics
The experiment was approved by the Animal Ethics Committee of the University of New
ed
England (Approval No: AEC 12-054). Health and animal husbandry practices complied with the Code of Practice for the Use of Animals for Scientific Purposes issued by the Australian
pt
Bureau of Animal Health (NMHRC, 1990).
ce
Experimental design and bird management This experiment was designed to investigate the effect of a starter level of SDPP on broiler performance and digestive physiology up to 35 d of age. Four inclusion levels of SDPP (0, 5,
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
on subsequent broiler performance, and digestive development and function. The hypothesis
10 and 20 g/kg diet) were used in lieu of meat meal in either maize- or wheat-based starter diets, which were fed from hatch to 10 d of age. The nutrient composition of the test product (SDPP) is shown in Table 1. The diets were identical in nutrient profiles and formulated to meet specifications (Tables 2 and 3) (Aviagen, 2007). After 10 d, the birds were switched to commercial-type grower (11-24 d) and finisher (25-35 d) diets. In a 4 x 2 factorial arrangement, a total of 480 Ross 308 d-old male chicks (initial weight, 41.0 ± 0.92 g) were
5
randomly assigned to 8 treatments, each with 6 replicates, 10 chickens per replicate. Chickens
were reared in multi-tiered brooder cages (600 x 420 x 23 cm) placed in a climate-controlled room up to 24 d, after which the birds were transferred to a metabolic cage room to 35 d. Feed and water were provided ad libitum. The room temperature was gradually decreased from 33 °C on d 1 to 24 °C at 35 d. Eighteen h of light was provided per d throughout the trial,
an us cr ip t
excluding d 1 to 7 during which 23 h of light was provided. Titanium dioxide (TiO 2 ) was incorporated in the grower diet as an indigestible marker at a rate of 5 kg/ton diet in order to
calculation of average feed intake and body weight. Mortality was recorded when it occurred
and feed per gain (feed intake/weight gain) was corrected for mortality. On d 10 and 24, two
birds from each cage were randomly selected and killed by cervical dislocation. The abdominal cavity was opened and visceral organs were weighed. The relative organ weight
M
was calculated as mass per unit of body weight (g/kg of body weight).
ed
On d 24, the whole pancreas and part of the proximal jejunum were taken for digestive enzyme assays. Ileal digesta were collected into plastic containers and immediately frozen.
pt
After freeze-drying (Martin Christ Gerfriertrocknungsanlagen, GmbH, Germany) the ileal digesta samples were ground in a small coffee grinder and stored at 4 °C in airtight containers
ce
for analysis of Ti , gross energy, protein and dry matter. Carcass weight and the weight of breast (boneless), thighs and drumsticks were recorded at 35 d. The relative weights were
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
measure nutrient digestibility. Feed leftovers and birds were weighed on d 10, 24 and 35 for
calculated as an indication of mass per unit of body weight (g/kg body weight). Tables 1, 2 and 3 near here
Tissue protein and digestive enzyme analyses To evaluate the activity of digestive enzymes and protein concentration, the jejunal tissue was processed according to the method described by Shirazi-Beechey et al. (1991). The pancreas was processed in a similar way to the jejunum except that Milli-Q water (Millipore Australia, North Ryde, Australia) was used in place of buffer and the entire tissue was homogenised.
6
The homogenised tissue was transferred to new tubes and centrifuged at high speed (30000 g) for 20 min at 5 ºC. Aliquots of supernatant were collected and used for various enzyme assays
and total protein content according to Nitsan et al. (1974). The activities of jejunal and pancreatic enzymes were measured by incubation with fixed substrate concentrations according to the methods previously described for other species (Holdsworth, 1970, Serviere-
an us cr ip t
Zaragoza et al., 1997) and standardised for poultry by Iji et al. (2001b). Tissue protein
concentration in both jejunum and pancreas was measured using the Coomassie dye-binding
Ileal digestibility of nutrients
The Ti content of the ileal digesta and diet samples was measured according to the method
described by Short et al. (1996). The crude protein (CP), gross energy (GE) and dry matter
M
(DM) of feed and freeze-dried ileal digesta samples were also analysed and related to the
indigestible marker, in order to calculate nutrient digestibility. The nitrogen content of ileal
ed
digesta and diet samples was determined according to the Dumas combustion technique following the method described by Sweeney (1989). The GE value of the samples was
pt
obtained as MJ/kg directly with a digital type bomb calorimeter (IKA®- WERKE, C7000,
ce
GMBH & CO., Staufen, Germany).
The digestibility coefficient of nutrients was calculated using the following equation: 𝑔 𝑔 𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛 ( 𝐷𝐷)/𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑇𝑇𝑇₂ ( 𝐷𝐷) 𝑘𝑘 𝑘𝑘 Digestibility coefficient = 1 − 𝑔 𝑔 𝐷𝐷𝐷𝐷 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛 ( 𝐷𝐷)/𝐷𝐷𝐷𝐷 𝑇𝑇𝑇₂ ( 𝐷𝐷) 𝑘𝑘 𝑘𝑘
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
procedure described by Bradford (1976).
Intestinal histomorphology Tissue samples were collected from the proximal jejunum and flushed with buffered saline and fixed in 10% neutral buffered formalin for histomorphological analysis. Samples were embedded in paraffin wax, sectioned and stained with haematoxylin and eosin. Sample
7
sections were captured at 10 x magnification using a Leica DM LB microscope (Leica
Microscope GmbH, Wetzlar, Germany) and morphometric indices were determined as described by Iji et al. (2001a). Images were digitised and the villus height (from the tip of the villus to the villus/crypt junction) and crypt depth (from the villus/crypt junction to the muscular junction) were measured in 7-10 well orientated villi for each jejunal section. The
area, as described by Iji et al. (2001a).
All data collected were analysed using the General Linear Model (GLM) procedure of
Minitab version 16 (Minitab Inc., 1998) for the main effect of SDPP concentration, type of grain, along with their interactions. Differences between mean values were determined using
M
Duncan’s multiple range test. Also regression analysis was carried out using polynomial option of Minitab version 16 (Minitab Inc., 1998) for the main effect of SDPP concentration.
Gross response
ed
RESULTS
pt
Up to 10 d of age feed intake was not affected by SDPP concentration, type of grain or their
ce
interaction (Table 4). Weight gain was significantly higher (P < 0.001) in the birds that received SDPP in their starter diets. Considered as a main factor, SDPP improved feed per gain (P < 0.001) in the starter phase. Neither weight gain nor feed per gain were affected by
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
Statistical analysis of data
an us cr ip t
basal and apical width of the villi was also measured in order to calculate the apparent surface
the type of grain fed in the starter diets. The interaction of SDPP concentration and grain type had no significant effects on the weight gain and feed per gain of broiler chickens. Table 4 near here When assessed to 35 d of age, starter SDPP concentration, type of grain and their interaction had no significant effects on the feed intake of broiler chickens (Table 5). Weight gain was generally higher (P < 0.01) in the birds that received the highest concentration of SDPP in their starter diets. The supplement also improved feed per gain (P < 0.001) between
8
1 and 35 d of age. The type of grain used had no effect on the weight gain and feed per gain of Table 5 near here
broiler chickens. Visceral organ weight
The relative weight of the visceral organs at d 10 of age was not affected by interaction
an us cr ip t
between SDPP and grain type (Table 6). As a main factor, SDPP increased the relative weight of gizzard+proventriculus but this was only significant (P < 0.007) at the highest
concentration of SDPP. The relative weight of the spleen was increased as a result of SDPP
(5 g/kg) of SDPP in the maize-based diets and highest concentration in the wheat-based diets. Liver weight tended to be increased (P < 0.07) as a result of SDPP consumption. Grain type had no significant effect on the relative weight of visceral organs at d 10 of broiler age.
M
At d 24 of age, spleen weight tended to be higher (P < 0.07) in birds that received
SDPP in their starter diets. Chickens on maize-based diets had significantly higher (P
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Subsequent growth performance and digestive physiology of broilers fed on starter diets containing spray-dried porcine plasma as a substitute for meat meal a
a
a
S.S.M. Beski , R.A. Swick & P.A. Iji a
School of Environmental and Rural Sciences, University of New England, Armidale, NSW 2351, Australia Accepted author version posted online: 01 Jul 2015.
Click for updates To cite this article: S.S.M. Beski, R.A. Swick & P.A. Iji (2015): Subsequent growth performance and digestive physiology of broilers fed on starter diets containing spray-dried porcine plasma as a substitute for meat meal, British Poultry Science, DOI: 10.1080/00071668.2015.1068429 To link to this article: http://dx.doi.org/10.1080/00071668.2015.1068429
Disclaimer: This is a version of an unedited manuscript that has been accepted for publication. As a service to authors and researchers we are providing this version of the accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to this version also.
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
1 Publisher: Taylor & Francis & British Poultry Science Ltd Journal: British Poultry Science DOI: 10.1080/00071668.2015.1068429
CBPS-2015-067
an us cr ip t
Subsequent growth performance and digestive physiology of broilers fed on starter diets
M
containing spray-dried porcine plasma as a substitute for meat meal
ed
S.S.M. BESKI, R.A. SWICK AND P.A. IJI
School of Environmental and Rural Sciences, University of New England, Armidale, NSW
pt
2351, Australia
ce
Running title: High quality proteins in starter diets
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
Ed. Kjaer, May 2015; MacLeod, June 2015
Correspondence to: Paul Iji, School of Environmental and Rural Sciences, University of New England, Armidale, NSW 2351, Australia. Email: [email protected] Phone: +61 2 67732082.
Accepted for publication 14th May 2015
2
Abstract. 1. A 4 x 2 factorial experiment was conducted to investigate the effect of inclusion of spray-dried porcine plasma (SDPP), in lieu of meat meal, in the starter diet on performance and digestive physiology of broiler chickens between hatch and 35 d of age. Four levels of SDPP (0, 5, 10 or 20 g/kg) were included in the starter diets in lieu of meat meal on either wheat- or maize-based diets.
an us cr ip t
2. Over the first 10 d, and throughout the 35 d experimental period, birds gained more body
weight with increasing concentrations of SDPP regardless to the type of grain used. Inclusion
35 d study. There was no significant effect of the type of grain and its interaction with SDPP on the body weight gain and feed per gain for the two assessed periods.
3. At d 10, the relative weight of the gizzard+proventriculus, spleen and liver increased with increasing concentrations of SDPP.
M
4. At d 24 of age the grain and SDPP inclusion significantly interacted, depressing the weight
ed
of bursa and spleen in birds that received the highest concentration of SDPP in the maizebased diet. Birds fed on the maize-based diets had higher relative weight of pancreas than
pt
those on the wheat-based diets.
5. Increasing concentrations of SDPP in the starter diet improved the activities of maltase,
ce
sucrase and alkaline phosphatase at 24 d of age. The interaction of grain and SDPP concentration was significant for sucrase activity in birds on the wheat-based diets. Chickens
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
of SDPP in the starter diet markedly improved feed per gain in the starter phase and across the
on maize-based diets had higher alkaline phosphatase and maltase activities than those on
wheat-based diets 6. Chicks that were offered SDPP-containing starter diets had longer villi, deeper crypts and lower villi/crypt than the control at d 24 of age regardless of the grain type used. Furthermore, longer villi and larger villi/crypt were found in chicken groups fed on wheat-based diets than those on maize-based diets.
3
7. Chickens on maize-based diets had higher dressing percentage and relative breast weight than those on wheat-based diets at d 35 of age.
8. It can be concluded that supplementation of starter diets with SDPP would be beneficial to the long-term growth of broiler chickens. The effect of the basal grain used in the diet is minimal.
an us cr ip t
INTRODUCTION
It is widely accepted that nutritional supplements given in the immediate post-hatch period
growth and overall development of chicks (Henderson et al., 2008). Broiler chicks have been shown to benefit from immediate access to feed. Although the focus of early nutrition has
been on the provision of energy, chicks benefit from a more balanced nutrient profile,
M
particularly containing amino acids. Blood products such as spray-dried whole blood, plasma
or red cells have been documented as a source of proteins with a good amino acid profile and
ed
digestibility, and have been used as ingredients in farm animal diets for many years (Castelló et al., 2004). Careful handling of the raw materials and utilisation of the spray-dried process
pt
have dramatically improved the quality and subsequent use of blood protein products in farm
ce
animal diets (Campbell, 1998). Spray-dried porcine plasma (SDPP) and similar products have been used by the pig industry to support piglets prior to and after weaning (Kats et al., 1994; Coffey and Cromwell, 2001; Van Dijk et al., 2001). As a high-quality animal protein source
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
help in the development of the digestive system, which improves the nutrient utilisation,
with an adequate supply of essential amino acids, SDPP increases diet palatability (Ermer et al., 1994) and improves immuno-competence (Coffey and Cromwell, 1995), and is usually considered to be an essential ingredient in the diet of early weaned pigs (Thacker, 1999). Positive effects have been observed in many studies due to the incorporation of porcine blood by-products, particularly SDPP, in the diets of piglets. These effects include improvement in development of the immune system, antibody functions, inflammatory
4
response and changes in intestinal morphology (Owusu-Asiedu et al., 2002; Rodriguez et al., 2007; Campbell et al., 2009; Moretó and Pérez-Bosque, 2009), small intestinal growth and activation of insulin-like growth factors (De Rodas et al., 1995; Jiang et al., 2000), and performance improvement (Mazurkiewicz et al., 1990; Pierce et al., 2005; Nofrarias et al., 2006). These results have increased the interest in the application of this high quality protein
an us cr ip t
product in the poultry industry too and particularly in the starter phase. The objective of this
study is to evaluate the effect of SDPP inclusion, as a substitute for meat meal, in starter diet
that was tested is that SDPP would support better growth response than meat meal, regardless of the dietary grain base.
MATERIAL AND METHODS
M
Animal ethics
The experiment was approved by the Animal Ethics Committee of the University of New
ed
England (Approval No: AEC 12-054). Health and animal husbandry practices complied with the Code of Practice for the Use of Animals for Scientific Purposes issued by the Australian
pt
Bureau of Animal Health (NMHRC, 1990).
ce
Experimental design and bird management This experiment was designed to investigate the effect of a starter level of SDPP on broiler performance and digestive physiology up to 35 d of age. Four inclusion levels of SDPP (0, 5,
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
on subsequent broiler performance, and digestive development and function. The hypothesis
10 and 20 g/kg diet) were used in lieu of meat meal in either maize- or wheat-based starter diets, which were fed from hatch to 10 d of age. The nutrient composition of the test product (SDPP) is shown in Table 1. The diets were identical in nutrient profiles and formulated to meet specifications (Tables 2 and 3) (Aviagen, 2007). After 10 d, the birds were switched to commercial-type grower (11-24 d) and finisher (25-35 d) diets. In a 4 x 2 factorial arrangement, a total of 480 Ross 308 d-old male chicks (initial weight, 41.0 ± 0.92 g) were
5
randomly assigned to 8 treatments, each with 6 replicates, 10 chickens per replicate. Chickens
were reared in multi-tiered brooder cages (600 x 420 x 23 cm) placed in a climate-controlled room up to 24 d, after which the birds were transferred to a metabolic cage room to 35 d. Feed and water were provided ad libitum. The room temperature was gradually decreased from 33 °C on d 1 to 24 °C at 35 d. Eighteen h of light was provided per d throughout the trial,
an us cr ip t
excluding d 1 to 7 during which 23 h of light was provided. Titanium dioxide (TiO 2 ) was incorporated in the grower diet as an indigestible marker at a rate of 5 kg/ton diet in order to
calculation of average feed intake and body weight. Mortality was recorded when it occurred
and feed per gain (feed intake/weight gain) was corrected for mortality. On d 10 and 24, two
birds from each cage were randomly selected and killed by cervical dislocation. The abdominal cavity was opened and visceral organs were weighed. The relative organ weight
M
was calculated as mass per unit of body weight (g/kg of body weight).
ed
On d 24, the whole pancreas and part of the proximal jejunum were taken for digestive enzyme assays. Ileal digesta were collected into plastic containers and immediately frozen.
pt
After freeze-drying (Martin Christ Gerfriertrocknungsanlagen, GmbH, Germany) the ileal digesta samples were ground in a small coffee grinder and stored at 4 °C in airtight containers
ce
for analysis of Ti , gross energy, protein and dry matter. Carcass weight and the weight of breast (boneless), thighs and drumsticks were recorded at 35 d. The relative weights were
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
measure nutrient digestibility. Feed leftovers and birds were weighed on d 10, 24 and 35 for
calculated as an indication of mass per unit of body weight (g/kg body weight). Tables 1, 2 and 3 near here
Tissue protein and digestive enzyme analyses To evaluate the activity of digestive enzymes and protein concentration, the jejunal tissue was processed according to the method described by Shirazi-Beechey et al. (1991). The pancreas was processed in a similar way to the jejunum except that Milli-Q water (Millipore Australia, North Ryde, Australia) was used in place of buffer and the entire tissue was homogenised.
6
The homogenised tissue was transferred to new tubes and centrifuged at high speed (30000 g) for 20 min at 5 ºC. Aliquots of supernatant were collected and used for various enzyme assays
and total protein content according to Nitsan et al. (1974). The activities of jejunal and pancreatic enzymes were measured by incubation with fixed substrate concentrations according to the methods previously described for other species (Holdsworth, 1970, Serviere-
an us cr ip t
Zaragoza et al., 1997) and standardised for poultry by Iji et al. (2001b). Tissue protein
concentration in both jejunum and pancreas was measured using the Coomassie dye-binding
Ileal digestibility of nutrients
The Ti content of the ileal digesta and diet samples was measured according to the method
described by Short et al. (1996). The crude protein (CP), gross energy (GE) and dry matter
M
(DM) of feed and freeze-dried ileal digesta samples were also analysed and related to the
indigestible marker, in order to calculate nutrient digestibility. The nitrogen content of ileal
ed
digesta and diet samples was determined according to the Dumas combustion technique following the method described by Sweeney (1989). The GE value of the samples was
pt
obtained as MJ/kg directly with a digital type bomb calorimeter (IKA®- WERKE, C7000,
ce
GMBH & CO., Staufen, Germany).
The digestibility coefficient of nutrients was calculated using the following equation: 𝑔 𝑔 𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛 ( 𝐷𝐷)/𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑇𝑇𝑇₂ ( 𝐷𝐷) 𝑘𝑘 𝑘𝑘 Digestibility coefficient = 1 − 𝑔 𝑔 𝐷𝐷𝐷𝐷 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛 ( 𝐷𝐷)/𝐷𝐷𝐷𝐷 𝑇𝑇𝑇₂ ( 𝐷𝐷) 𝑘𝑘 𝑘𝑘
Ac
Downloaded by [OARE Consortium] at 03:39 07 July 2015
procedure described by Bradford (1976).
Intestinal histomorphology Tissue samples were collected from the proximal jejunum and flushed with buffered saline and fixed in 10% neutral buffered formalin for histomorphological analysis. Samples were embedded in paraffin wax, sectioned and stained with haematoxylin and eosin. Sample
7
sections were captured at 10 x magnification using a Leica DM LB microscope (Leica
Microscope GmbH, Wetzlar, Germany) and morphometric indices were determined as described by Iji et al. (2001a). Images were digitised and the villus height (from the tip of the villus to the villus/crypt junction) and crypt depth (from the villus/crypt junction to the muscular junction) were measured in 7-10 well orientated villi for each jejunal section. The
area, as described by Iji et al. (2001a).
All data collected were analysed using the General Linear Model (GLM) procedure of
Minitab version 16 (Minitab Inc., 1998) for the main effect of SDPP concentration, type of grain, along with their interactions. Differences between mean values were determined using
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Duncan’s multiple range test. Also regression analysis was carried out using polynomial option of Minitab version 16 (Minitab Inc., 1998) for the main effect of SDPP concentration.
Gross response
ed
RESULTS
pt
Up to 10 d of age feed intake was not affected by SDPP concentration, type of grain or their
ce
interaction (Table 4). Weight gain was significantly higher (P < 0.001) in the birds that received SDPP in their starter diets. Considered as a main factor, SDPP improved feed per gain (P < 0.001) in the starter phase. Neither weight gain nor feed per gain were affected by
Ac
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Statistical analysis of data
an us cr ip t
basal and apical width of the villi was also measured in order to calculate the apparent surface
the type of grain fed in the starter diets. The interaction of SDPP concentration and grain type had no significant effects on the weight gain and feed per gain of broiler chickens. Table 4 near here When assessed to 35 d of age, starter SDPP concentration, type of grain and their interaction had no significant effects on the feed intake of broiler chickens (Table 5). Weight gain was generally higher (P < 0.01) in the birds that received the highest concentration of SDPP in their starter diets. The supplement also improved feed per gain (P < 0.001) between
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1 and 35 d of age. The type of grain used had no effect on the weight gain and feed per gain of Table 5 near here
broiler chickens. Visceral organ weight
The relative weight of the visceral organs at d 10 of age was not affected by interaction
an us cr ip t
between SDPP and grain type (Table 6). As a main factor, SDPP increased the relative weight of gizzard+proventriculus but this was only significant (P < 0.007) at the highest
concentration of SDPP. The relative weight of the spleen was increased as a result of SDPP
(5 g/kg) of SDPP in the maize-based diets and highest concentration in the wheat-based diets. Liver weight tended to be increased (P < 0.07) as a result of SDPP consumption. Grain type had no significant effect on the relative weight of visceral organs at d 10 of broiler age.
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At d 24 of age, spleen weight tended to be higher (P < 0.07) in birds that received
SDPP in their starter diets. Chickens on maize-based diets had significantly higher (P
