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REVIEW

Whole-grain feeding for chicken-meat production: possible mechanisms driving enhanced energy utilisation and feed conversion

Sonia Yun Liu A , Ha H. Truong A and Peter H. Selle A B
+ Author Affiliations
- Author Affiliations

A Poultry Research Foundation within The University of Sydney, 425 Werombi Road, Camden, NSW 2570, Australia.

B Corresponding author. Email: peter.selle@sydney.edu.au

Animal Production Science 55(5) 559-572 https://doi.org/10.1071/AN13417
Submitted: 9 October 2013  Accepted: 6 January 2014   Published: 28 March 2014

Abstract

The practice of offering some whole grain to broiler chickens alongside a balancing concentrate is meeting increasing acceptance in certain regions, including Europe, Canada and Australia. Whole-grain feeding (WGF) regimes provide economic advantages by effectively reducing feed costs but, to varying extents, WGF regimes also generate improvements in energy utilisation and feed conversion efficiency. However, the context in which these improvements are best realised has yet to be defined adequately. The outstanding response to WGF is the development of heavier relative gizzard weights; however, the causative factors and biophysical and biochemical consequences of heavier, and presumably more functional, gizzards have not been properly investigated. It follows that heavier gizzards would enhance the initiation of protein digestion by pepsin and hydrochloric acid and facilitate amylase-induced starch digestion in the small intestine by the prior physical disruption of starch granules. However, it appears that improvements realised by WGF in energy utilisation and feed efficiency cannot be attributed entirely to heavier gizzards. One alternative or additional possibility is that WGF may influence starch digestive dynamics and provide more gradually or slowly digestible starch, which would benefit energy utilisation and feed efficiency. However, if this is the case, the genesis of this provision is not clear, although it may be associated with larger grain particle sizes and/or increased episodes of reverse peristalsis, but not retarded gut passage rates. The present paper reviews the essentially positive impacts of WGF on energy utilisation and feed conversion efficiency and considers the contexts in which these responses may be best realised and the possible mechanisms driving better performance under WGF regimes for chicken-meat production.

Additional keywords: digestion dynamics, feed conversion ratios, gizzard, pancreas, pepsin, slowly digestible starch.


References

Amerah AM, Ravindran V (2008) Influence of method of whole-wheat feeding on the performance, digestive tract development and carcass traits of broiler chickens. Animal Feed Science and Technology 147, 326–339.
Influence of method of whole-wheat feeding on the performance, digestive tract development and carcass traits of broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Amerah AM, Ravindran V, Lentle RG (2009) Influence of insoluble fibre and whole wheat inclusion on the performance, digestive tract development and ileal microbiota profile of broiler chickens. British Poultry Science 50, 366–375.
Influence of insoluble fibre and whole wheat inclusion on the performance, digestive tract development and ileal microbiota profile of broiler chickens.Crossref | GoogleScholarGoogle Scholar | 19637037PubMed |

Banfield MJ, Forbes JM (2001) Effects of whole wheat dilution versus substitution on coccidiosis in broiler chickens. The British Journal of Nutrition 86, 89–95.
Effects of whole wheat dilution versus substitution on coccidiosis in broiler chickens.Crossref | GoogleScholarGoogle Scholar | 11432769PubMed |

Bennett CD, Classen HL, Riddell C (2002) Feeding broiler chickens wheat and barley diets containing whole, ground and pelleted grain. Poultry Science 81, 995–1003.
Feeding broiler chickens wheat and barley diets containing whole, ground and pelleted grain.Crossref | GoogleScholarGoogle Scholar | 12162361PubMed |

Biggs P, Parsons CM (2009) The effects of whole grains on nutrient digestibilities, growth performance, and cecal short-chain fatty acid concentrations in young chicks fed ground corn-soybean meal diets. Poultry Science 88, 1893–1905.
The effects of whole grains on nutrient digestibilities, growth performance, and cecal short-chain fatty acid concentrations in young chicks fed ground corn-soybean meal diets.Crossref | GoogleScholarGoogle Scholar | 19687275PubMed |

Cabrera MR (1994) Effects of sorghum genotype and particle size on milling characteristics and performance of finishing pigs, broiler chickens, and laying hens. MSc Thesis, Kansas State University, Manhatten, KS.

Cant JP, McBride BW, Croom WJ (1996) The regulation of intestinal metabolism and its impact on whole animal energetics. Journal of Animal Science 74, 2541–2553.

Clark PM, Behnke KC, Farenholz AC (2009) Effects of feeding cracked corn and concentrate protein pellets on broiler growth performance. Journal of Applied Poultry Research 18, 259–268.
Effects of feeding cracked corn and concentrate protein pellets on broiler growth performance.Crossref | GoogleScholarGoogle Scholar |

Crévieu-Gabriel I, Gomez J, Caffin JP, Carré B (1999) Comparison of pig and chicken pepsins for protein hydrolysis. Reproduction, Nutrition, Development 39, 443–454.
Comparison of pig and chicken pepsins for protein hydrolysis.Crossref | GoogleScholarGoogle Scholar | 10493150PubMed |

Cumming RB (1992a) The biological control of coccidiosis by choice feeding. In ‘Proceedings, 19th World Poultry Congress 2’. pp. 425–428. (Dutch Branch of Worlds Poultry Science Association: Amsterdam)

Cumming RB (1992b) Mechanisms of biological control of coccidiosis in chickens. Proceedings of the Australian Poultry Science Symposium 4, 46–51.

Cumming RB (1994) Opportunities for whole grain feeding. In ‘Proceedings 9th European poultry conference. Vol II’. pp. 219–222. (Worlds Poultry Science Association: Glasgow, UK)

del Alamo AG, Verstegen MWA, den Hartog LA, de Ayala PP, Villamide MJ (2009) Wheat starch digestion rate affects broiler performance. Poultry Science 88, 1666–1675.
Wheat starch digestion rate affects broiler performance.Crossref | GoogleScholarGoogle Scholar | 19590082PubMed |

Delezie E, Maertens L, Huyghebaert G, Lippens M (2009) Can choice feeding improve performance and N-retention of broilers compared to a standard three-phase feeding schedule? British Poultry Science 50, 573–582.
Can choice feeding improve performance and N-retention of broilers compared to a standard three-phase feeding schedule?Crossref | GoogleScholarGoogle Scholar | 19904636PubMed |

Duke GE (1982) Gastrointestinal motility and its regulation. Poultry Science 61, 1245–1256.
Gastrointestinal motility and its regulation.Crossref | GoogleScholarGoogle Scholar | 7134105PubMed |

Engberg RM, Hedemann MS, Steenfeldt S, Jensen BB (2004) Influence of whole wheat and xylanase on broiler performance and microbial composition and activity in the digestive tract. Poultry Science 83, 925–938.
Influence of whole wheat and xylanase on broiler performance and microbial composition and activity in the digestive tract.Crossref | GoogleScholarGoogle Scholar | 15206619PubMed |

Enting H, Pos J, Weurding RE, Veldman A (2005) Starch digestion rate affects broiler performance. Proceedings, Australian Poultry Science Symposium 17, 17–20.

Ferket P (2000) Feeding whole grains to poultry improves gut health. Feedstuffs 72, 12–16.

Fleming SE, Zambell KL, Fitch MD (1997) Glucose and glutamine provide similar proportions of energy to mucosal cells of rat small intestine. American Journal of Physiology. Gastrointestinal and Liver Physiology 273, G968–G978.

Forbes JM, Covasa M (1995) Application of diet selection by poultry with particular reference to whole cereals. World’s Poultry Science Journal 51, 149–165.
Application of diet selection by poultry with particular reference to whole cereals.Crossref | GoogleScholarGoogle Scholar |

Fritz JC (1935) Comparison of digestibility in gizzardectomized fowls. Poultry Science 14, 302 [Abstract]

Gabriel I, Mallet S, Leconte M, Fort G, Naciri M (2003a) Effects of whole wheat feeding on the development of coccidial infection in broiler chickens. Poultry Science 82, 1668–1676.
Effects of whole wheat feeding on the development of coccidial infection in broiler chickens.Crossref | GoogleScholarGoogle Scholar | 14653460PubMed |

Gabriel I, Mallet S, Leconte M (2003b) Differences in the digestive tract characteristics of broiler chickens fed on a complete pelleted diet or on whole wheat added to the pelleted protein concentrate. British Poultry Science 44, 283–290.
Differences in the digestive tract characteristics of broiler chickens fed on a complete pelleted diet or on whole wheat added to the pelleted protein concentrate.Crossref | GoogleScholarGoogle Scholar | 12828214PubMed |

Gabriel I, Mallet S, Leconte M, Travel A, Lalles JP (2008) Effects of whole wheat feeding on the development of the digestive tract of broiler chickens. Animal Feed Science and Technology 142, 144–162.
Effects of whole wheat feeding on the development of the digestive tract of broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Gous RM, Swatson HK (2000) Mixture experiments: a severe test of the ability of a broiler chicken to make the right choice. British Poultry Science 41, 136–140.
Mixture experiments: a severe test of the ability of a broiler chicken to make the right choice.Crossref | GoogleScholarGoogle Scholar | 10890207PubMed |

Guan D, Green GM (1996) Significance of peptic digestion in rat pancreatic secretory response to dietary protein. American Journal of Physiology. Gastrointestinal and Liver Physiology 271, G42–G47.

Hetland H, Svihus B, Olaisen V (2002) Effect of feeding whole cereals on performance, starch digestibility and duodenal particle size distribution in broiler chickens. British Poultry Science 43, 416–423.
Effect of feeding whole cereals on performance, starch digestibility and duodenal particle size distribution in broiler chickens.Crossref | GoogleScholarGoogle Scholar | 12195801PubMed |

Hetland H, Svihus B, Krogdahl Å (2003) Effects of oat hulls and wood shavings on digestion in broilers and layers fed diets based on whole or ground wheat. British Poultry Science 44, 275–282.
Effects of oat hulls and wood shavings on digestion in broilers and layers fed diets based on whole or ground wheat.Crossref | GoogleScholarGoogle Scholar | 12828213PubMed |

Jensen JF (1994) Choice feeding in practice. In ‘Proceedings, 9th European poultry conference II’. pp. 223–236. (UK Branch of Worlds Poultry Science Association: Glasgow, UK)

Jones GPD, Taylor RD (2001) The incorporation of whole grain into pelleted broiler chicken diets: production and physiological responses. British Poultry Science 42, 477–483.
The incorporation of whole grain into pelleted broiler chicken diets: production and physiological responses.Crossref | GoogleScholarGoogle Scholar |

Kiiskinen T (1996) Feeding whole grain with pelleted diets to growing broiler chickens. Agricultural and Food Science in Finland 5, 167–175.

Krabbe EL (2000) Efeito do peso ao nascer, de níveis e formas físicas de administração de sódio e do diâmetro geométrico médio das partículas sobre o desempenho de frangos de corte até 21 dias de idade. Universidade Federal do Rio Grande do Sul publication, Porto Alegre, Brazil.

Krehbiel CR, Matthews JC (2003) Absorption of amino acids and peptides. In ‘Amino acids in animal nutrition’. 2nd edn. (Ed. JPP D’Mello) pp. 41–70. (CAB International: Wallingford, UK)

Liu SY, Selle PH, Khoddami A, Roberts PH, Cowieson AJ (2014a) Graded inclusions of sodium metabisulphite in sorghum-based diets. II. Modification of starch pasting properties in vitro and beneficial impacts on starch digestion dynamics in broiler chickens. Animal Feed Science and Technology
Graded inclusions of sodium metabisulphite in sorghum-based diets. II. Modification of starch pasting properties in vitro and beneficial impacts on starch digestion dynamics in broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Liu SY, Peron A, Cadogan DJ, Truong HH, Selle PH (2014b) Phytase supplementation of maize-, sorghum- and wheat-based diets. Proceedings of the Australian Poultry Science Symposium 25, 45–48.

Mastika M, Cumming RB (1987) Effect of previous experience, and environmental variations on the performance and pattern of feed intake of choice fed and complete fed broilers. In ‘Recent advances in animal nutrition in Australia’. pp. 260–282. (University of New England: Armidale, NSW)

McIntosh JI, Slinger SJ, Sibbald IR, Ashton GC (1962) Factors affecting the metabolisable energy content of poultry feeds. Poultry Science 41, 445–456.
Factors affecting the metabolisable energy content of poultry feeds.Crossref | GoogleScholarGoogle Scholar |

Meyer JH, Kelly GA (1976) Canine pancreatic responses to intestinally perfused proteins and protein digests. The American Journal of Physiology 231, 682–691.

Moran ET (1982) Starch digestion in fowl. Poultry Science 61, 1257–1267.
Starch digestion in fowl.Crossref | GoogleScholarGoogle Scholar | 7134106PubMed |

Nahas J, Lefrancois MR (2001) Effects of feeding locally grown whole barley with or without enzyme addition and whole wheat on broiler performance and carcass traits. Poultry Science 80, 195–202.
Effects of feeding locally grown whole barley with or without enzyme addition and whole wheat on broiler performance and carcass traits.Crossref | GoogleScholarGoogle Scholar | 11233008PubMed |

Nir I, Hillel R, Shefet G, Nitsan Z (1994) Effect of grain particle size on performance. 2. Grain texture interactions. Poultry Science 73, 781–791.
Effect of grain particle size on performance. 2. Grain texture interactions.Crossref | GoogleScholarGoogle Scholar | 8072920PubMed |

Nishi T, Hara H, Hira T, Tomita F (2001) Dietary protein peptic hydrolysates stimulate cholecystokinin realease via direct sensing by rat mucosal cells. Experimental Biology and Medicine 266, 1031–1036.

Noirot V, Bouvarel I, Barrier-Guilloy B, Castaing J, Zwick JL, Picard M (1998) Whole cereal grains in broiler nutrition: the come back? Productions Animales 11, 349–357.

Olver MD (1996) Choice feeding of broilers whole maize or whole sorghum as an energy source. Pluimvee Bulletin May, 248–249.

Paterson LA, Mitchell JR, Hill SE, Blanshard JMV (1996) Evidence for sulfite induced oxidative reductive polymerisation of starch polysaccharides. Carbohydrate Research 292, 143–151.
Evidence for sulfite induced oxidative reductive polymerisation of starch polysaccharides.Crossref | GoogleScholarGoogle Scholar |

Paterson LA, Hill SE, Mitchell JR, Blanshard JMV (1997) Sulfite and oxidative–reductive depolymerization reactions. Food Chemistry 60, 143–147.
Sulfite and oxidative–reductive depolymerization reactions.Crossref | GoogleScholarGoogle Scholar |

Plavnik I, Macovsky B, Sklan D (2002) Effect of feeding whole wheat on performance of broiler chickens. Animal Feed Science and Technology 96, 229–236.
Effect of feeding whole wheat on performance of broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Preston CM, McCracken KJ, McAllister A (2000) Effect of diet form and enzyme supplementation on growth, efficiency and energy utilisation of wheat-based diets for broilers. British Poultry Science 41, 324–331.
Effect of diet form and enzyme supplementation on growth, efficiency and energy utilisation of wheat-based diets for broilers.Crossref | GoogleScholarGoogle Scholar | 11081428PubMed |

Ravindran V, Selle PH, Bryden WL (1999) Effects of phytase supplementation, individually and in combination, with glycanase on the nutritive value of wheat and barley. Poultry Science 78, 1588–1595.
Effects of phytase supplementation, individually and in combination, with glycanase on the nutritive value of wheat and barley.Crossref | GoogleScholarGoogle Scholar | 10560833PubMed |

Ravindran V, Wu YB, Thomas DG, Morel PCH (2006) Influence of whole wheat feeding on the development of gastrointestinal tract and performance of broiler chickens. Australian Journal of Agricultural Research 57, 21–26.
Influence of whole wheat feeding on the development of gastrointestinal tract and performance of broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Rogel AM, Balnave D, Bryden WL, Annison EF (1987a) Improvement of raw potato starch digestion in chickens by feeding oat hulls and other fibrous feedstuffs. Australian Journal of Agricultural Research 38, 629–637.
Improvement of raw potato starch digestion in chickens by feeding oat hulls and other fibrous feedstuffs.Crossref | GoogleScholarGoogle Scholar |

Rogel AM, Annison EF, Bryden WL, Balnave D (1987b) The digestion of wheat starch in broiler chickens. Australian Journal of Agricultural Research 38, 639–649.
The digestion of wheat starch in broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Rose SP, Fielden M, Foote WR, Gardin P (1995) Sequential feeding of whole wheat to growing broiler chickens. British Poultry Science 36, 97–111.
Sequential feeding of whole wheat to growing broiler chickens.Crossref | GoogleScholarGoogle Scholar | 7614030PubMed |

Rutkowski A, Wiaz M (2001) Effect of feeding whole or ground grain on the weight of the gizzard and pH of digesta of broiler chickens. Journal of Animal and Feed Sciences 10, 285–289.

Sacranie A, Iji PA, Mikkelsen LL, Choct M (2007) Occurrence of reverse peristalsis in broiler chickens. Proceedings of the Australian Poultry Science Symposium 19, 161–164.

Selle PH, Ravindran V (2007) Microbial phytase in poultry nutrition. Animal Feed Science and Technology 135, 1–41.
Microbial phytase in poultry nutrition.Crossref | GoogleScholarGoogle Scholar |

Selle PH, Ravindran V, Caldwell RA, Bryden WL (2000) Phytate and phytase: consequences for protein utilisation. Nutrition Research Reviews 13, 255–278.
Phytate and phytase: consequences for protein utilisation.Crossref | GoogleScholarGoogle Scholar | 19087442PubMed |

Selle PH, Walker AR, Bryden WL (2003) Total and phytate-phosphorus contents and phytase activity of Australian-sourced feed ingredients for pigs and poultry. Australian Journal of Experimental Agriculture 43, 475–479.
Total and phytate-phosphorus contents and phytase activity of Australian-sourced feed ingredients for pigs and poultry.Crossref | GoogleScholarGoogle Scholar |

Selle PH, Cowieson AJ, Cowieson NP, Ravindran V (2012a) Protein–phytate interactions in pig and poultry nutrition; a reappraisal. Nutrition Research Reviews 25, 1–17.
Protein–phytate interactions in pig and poultry nutrition; a reappraisal.Crossref | GoogleScholarGoogle Scholar | 22309781PubMed |

Selle PH, Liu SY, Cai J, Cowieson AJ (2012b) Steam-pelleting and feed form of broiler diets based on three coarsely ground sorghums influences growth performance, nutrient utilisation, starch and nitrogen digestibility. Animal Production Science 52, 842–852.
Steam-pelleting and feed form of broiler diets based on three coarsely ground sorghums influences growth performance, nutrient utilisation, starch and nitrogen digestibility.Crossref | GoogleScholarGoogle Scholar |

Selle PH, Liu SY, Cowieson AJ (2013a) Steam-pelleting temperatures, grain variety, feed form and protease supplementation of mediumly ground sorghum-based broiler diets: influences on growth performance, relative gizzard weights, nutrient utilisation, starch and nitrogen digestibility. Animal Production Science 53, 378–387.
Steam-pelleting temperatures, grain variety, feed form and protease supplementation of mediumly ground sorghum-based broiler diets: influences on growth performance, relative gizzard weights, nutrient utilisation, starch and nitrogen digestibility.Crossref | GoogleScholarGoogle Scholar |

Selle PH, Liu SY, Cai J, Cowieson AJ (2014a) Steam-pelleting temperatures and grain variety of finely-ground, sorghum-based broiler diets. I. Influence on growth performance, relative gizzard weights, nutrient utilisation, starch and nitrogen digestibility. Animal Production Science 54, 339–346.
Steam-pelleting temperatures and grain variety of finely-ground, sorghum-based broiler diets. I. Influence on growth performance, relative gizzard weights, nutrient utilisation, starch and nitrogen digestibility.Crossref | GoogleScholarGoogle Scholar |

Selle PH, Liu SY, Cai J, Caldwell RA, Cowieson AJ (2014b) Graded inclusions of sodium metabisulphite in sorghum-based diets. I. Reduction of disulphide cross-linkages in vitro and enhancement of energy utilisation and feed conversion efficiency in broiler chickens. Animal Feed Science and Technology
Graded inclusions of sodium metabisulphite in sorghum-based diets. I. Reduction of disulphide cross-linkages in vitro and enhancement of energy utilisation and feed conversion efficiency in broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Shariatmadari F, Forbes JM (1993) Growth and food intake responses to diets of different protein contents and a choice between diets containing two concentrations of protein in broiler and layer strains of chicken. British Poultry Science 34, 959–970.
Growth and food intake responses to diets of different protein contents and a choice between diets containing two concentrations of protein in broiler and layer strains of chicken.Crossref | GoogleScholarGoogle Scholar | 8156434PubMed |

Simon J (1989) Chicken as a useful species for the comprehension of insulin action. Critical Reviews in Poultry Biology 2, 121–148.

Starck JM (1999) Phenotypic flexibility in the avian gizzard: rapid, reversible and repeated changes in organ size in response to changes in dietary fibre content. The Journal of Experimental Biology 202, 3171–3179.

Stoll B, Henry J, Reeds PJ, Yu H, Jahoor F, Burrin DG (1998) Catabolism dominates the first-pass intestinal metabolism of dietary amino acids in milk protein-fed piglets. The Journal of Nutrition 128, 606–614.

Svihus B (2001a) Norwegian poultry industry converts to whole grain pellets. World Politics 17, 20–21.

Svihus B (2001b) Research note: a consistent low starch digestibility observed in pelleted broiler chicken diets containing high levels of different wheat varieties. Animal Feed Science and Technology 92, 45–49.
Research note: a consistent low starch digestibility observed in pelleted broiler chicken diets containing high levels of different wheat varieties.Crossref | GoogleScholarGoogle Scholar |

Svihus B (2011) The gizzard: function, influence of diet structure and effects on nutrient availability. World’s Poultry Science Journal 67, 207–224.
The gizzard: function, influence of diet structure and effects on nutrient availability.Crossref | GoogleScholarGoogle Scholar |

Svihus B, Hetland H (2001) Ileal starch digestibility in growing broiler chickens fed on a wheat-based diet is improved by mash feeding, dilution with cellulose or whole wheat inclusion. British Poultry Science 42, 633–637.
Ileal starch digestibility in growing broiler chickens fed on a wheat-based diet is improved by mash feeding, dilution with cellulose or whole wheat inclusion.Crossref | GoogleScholarGoogle Scholar | 11811915PubMed |

Svihus B, Herstad O, Newman CW, Newman RK (1997) Comparison of performance and intestinal characteristics of broiler chickens fed on diets containing whole, rolled or ground barley. British Poultry Science 38, 524–529.
Comparison of performance and intestinal characteristics of broiler chickens fed on diets containing whole, rolled or ground barley.Crossref | GoogleScholarGoogle Scholar | 9510997PubMed |

Svihus B, Hetland H, Choct M, Sundby F (2002) Passage rate through the anterior digestive tract of broiler chickens fed ground and whole wheat. British Poultry Science 43, 662–668.
Passage rate through the anterior digestive tract of broiler chickens fed ground and whole wheat.Crossref | GoogleScholarGoogle Scholar | 12555890PubMed |

Svihus B, Juvik E, Hetland H, Krogdahl A (2004) Causes for the improvement in nutritive value of broiler chicken diets with whole wheat instead of ground wheat. British Poultry Science 45, 55–60.
Causes for the improvement in nutritive value of broiler chicken diets with whole wheat instead of ground wheat.Crossref | GoogleScholarGoogle Scholar | 15115201PubMed |

Svihus B, Sacranie A, Denstaldi V, Choct M (2010) Nutrient utilization and functionality of the anterior digestive tract caused by intermittent feeding and inclusions of whole wheat in diets for broiler chicks. Poultry Science 89, 2617–2625.
Nutrient utilization and functionality of the anterior digestive tract caused by intermittent feeding and inclusions of whole wheat in diets for broiler chicks.Crossref | GoogleScholarGoogle Scholar | 21076099PubMed |

Taylor RD, Jones GPD (2004a) The incorporation of whole grain inclusion in pelleted broiler chicken diets II. Gastrointestinal and digesta characteristics. British Poultry Science 45, 237–246.
The incorporation of whole grain inclusion in pelleted broiler chicken diets II. Gastrointestinal and digesta characteristics.Crossref | GoogleScholarGoogle Scholar | 15222421PubMed |

Taylor RD, Jones GPD (2004b) The influence of whole grain inclusion in pelleted broiler chicken diets on proventricular dilation and ascites mortality. British Poultry Science 45, 247–254.
The influence of whole grain inclusion in pelleted broiler chicken diets on proventricular dilation and ascites mortality.Crossref | GoogleScholarGoogle Scholar | 15222422PubMed |

Uddin MS, Rose SP, Hiscock TA, Bonnet S (1996) A comparison of the energy availability for chickens of ground and whole grain samples of two wheat varieties. British Poultry Science 37, 347–357.
A comparison of the energy availability for chickens of ground and whole grain samples of two wheat varieties.Crossref | GoogleScholarGoogle Scholar |

Vaintraub IA, Bulmaga VP (1991) Effect of phytate on the in vitro activity of digestive proteinases. Journal of Agricultural and Food Chemistry 39, 859–861.
Effect of phytate on the in vitro activity of digestive proteinases.Crossref | GoogleScholarGoogle Scholar |

Van Der Meulen J, Bakker JGM, Smits B, de Visser H (1997) Effect of source of starch on net portal flux of glucose, lactate, volatile fatty acids and amino acid in the pig. The British Journal of Nutrition 78, 533–544.
Effect of source of starch on net portal flux of glucose, lactate, volatile fatty acids and amino acid in the pig.Crossref | GoogleScholarGoogle Scholar | 9389882PubMed |

Weurding RE (2002) Kinetics of starch digestion and performance of broiler chickens. PhD Thesis. Wageningen University, The Netherlands.

Weurding RE, Veldman A, Veen WAG, van der Aar PJ, Verstegen MWA (2001a) Starch digestion rate in the small intestine of broiler chickens differs amongst feedstuffs. The Journal of Nutrition 131, 2329–2335.

Weurding RE, Veldman A, Veen WAG, van der Aar PJ, Verstegen MWA (2001b) In vitro starch digestion correlates well with rate and extent of starch digestion in broiler chickens. The Journal of Nutrition 131, 2336–2342.

Weurding RE, Enting H, Verstegen MWA (2003a) The relation between starch digestion rate and amino acid level in broiler chickens. Poultry Science 82, 279–284.
The relation between starch digestion rate and amino acid level in broiler chickens.Crossref | GoogleScholarGoogle Scholar | 12619806PubMed |

Weurding RE, Enting H, Verstegen MWA (2003b) The effect of site of starch digestion on performance of broiler chickens. Animal Feed Science and Technology 110, 175–184.
The effect of site of starch digestion on performance of broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Wu YB, Ravindran V (2004) Influence of whole wheat inclusion and xylanase supplementation on the performance digestive tract measurements and carcass characteristics of broiler chickens. Animal Feed Science and Technology 116, 129–139.
Influence of whole wheat inclusion and xylanase supplementation on the performance digestive tract measurements and carcass characteristics of broiler chickens.Crossref | GoogleScholarGoogle Scholar |

Wu YB, Ravindran V, Thomas DG, Birtles MJ, Hendriks WH (2004) Influence of method of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy, digestive tract measurements and gut morphology of broilers. British Poultry Science 45, 385–394.
Influence of method of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy, digestive tract measurements and gut morphology of broilers.Crossref | GoogleScholarGoogle Scholar | 15327125PubMed |