Wheat value: improvements by feed technology, plant breeding and animal genetics

Abstract

Wheat is a common ingredient in poultry diets, especially in Europe. Due to its low protein and high starch levels, wheat is essentially used as an energy supplier. Nutritional values of wheat samples vary according to their nutrient content and digestibilities. Variations of nutrient contents may be associated with cultivars and environmental conditions. Digestibility variations in growing chicks may be associated with these factors, and also, with technological treatments of diets and genetic origin of birds. Total nutrient content (starch, protein, lipids and sugars) is strongly related to fibre content through a negative relationship. A large part of fibre content variations of wheat samples depends on their cultivar origin. Wheat protein content depends both on cultivar and environmental conditions. High yield cultivars are often associated with low protein content. Lipid and starch digestibilities of wheat diets given to growing birds may sometimes be rather low. The main reason of the low lipid digestibility values observed with some wheat samples is the high viscosity of water-extract induced by their water-soluble arabinoxylans. This viscosity results from a combination of several variables including the potential applied viscosity value (PAV as mL/g) of the wheat cultivar, the endogenous and exogenous xylanases, and the endogenous anti-xylanase contents. Environmental conditions and technological treatments are major factors acting on xylanase and anti-xylanase contents. A part of wheat starch digestibility variations may be related to accessibility problems in coarse particles due to hard wheat cultivars and coarse grinding. However, coarse particles may be positive for stimulating feed intake of mash diets, and protecting against intestinal transit disorders. In growing chicks, genetic origin of birds may result in very large variations in the digestibility of wheat diets, as observed with the divergent D+ and D-"Digestion" lines selected on the digestion ability of a wheat diet. In 3 w old chickens selected over 4 generations, the AMEn value of a Rialto wheat diet was 13% lower in D-than in D+ Improving wheat value: B. Carré et al. birds (P=0.0001). D-birds showed 10% variations in AMEn values between fourcereal diets (P=0.0003), while D+ birds showed only 4% variations (P=0.0006). In D+ birds, AMEn values of wheat and maize diets were the same (14,488 vs. 14,538 J/g DM), while, in D-birds, AMEn values of wheat diets were 5% lower (P=0.015) than the maize diet value (13,106 vs. 13,809 J/g DM).

Chemical composition and nutritional value of different wheat cultivars for broiler chickens

“…Carré et al (2002) reported that in broilers, high digesta viscosity negatively affected lipid and starch digestibility, while the digestibility of protein of different wheat cultivars was similar. Carré et al (2007) stressed that the viscosity of wheat in the chicken digestive tract results from a combination of several variables, among others from the physico-chemical characteristics of soluble NSP, endogenous xylanases, activity of proteinaceaous inhibitors, and technological treatment (grinding, pelleting).…”

“…At least several hundred wheat cultivars are used throughout the world, however, most of the technological parameters that describe the quality of seeds have been defi ned for human utilization (Carré et al, 2007). In Europe wheat is commonly used in poultry diets, but the nutritional potential of wheat cultivars in poultry feeding remains unknown.…”

“…In Europe wheat is commonly used in poultry diets, but the nutritional potential of wheat cultivars in poultry feeding remains unknown. It is generally admitted that there is no problem when wheat is given to adult birds, but effects in broiler production are often unsatisfactory due to the variability of energy value between cultivars (McCracken and Quintin, 2000;Steenfeld, 2001;Pirgozliev et al, 2003;Carré et al, 2007). The content and physico-chemical characteristics of non-starch polysaccharides (NSP) can infl uence intestinal viscosity, nutrient digestibility and apparent metabolizable energy value (AME N ) in chickens (Mollah et al, 1983;Dusel et al, 1997;Pirgozliev et al, 2003).…”

Comparison of gastrointestinal transit times between chickens from D+ and D− genetic lines selected for divergent digestion efficiency

“…D 1 and D 2 chicken lines were developed because it appeared that the overall variability in digestion efficiencies in growing chickens fed various wheat diets came largely from individual birds, and much less came from wheat samples (Choct et al, 1999;McCracken et al, 2001;Carré et al, 2002 and. Therefore, genetic selection appeared to be an efficient way to improve digestion efficiency in growing chickens fed on wheat diets (Mignon-Grasteau et al, 2004;Carré et al, 2007). Besides such economic interest, D 1 and D 2 lines also represent a unique model for the study of physiological and genetic limiting factors of digestion.…”

Chemical composition and energetic values of wheat and its sub-products for broiler chicken

“…Its nutritional potential in feeding birds is not well known due to the variability of energy values among its cultivars (CARRÉ et al, 2007). Triticale is obtained by artificially crossing wheat with rye, and has a higher protein and lower fiber content compared with wheat bran.…”