Effect of rate and extent of starch digestion on broiler and laying hen performance E. Herwig, R. K. Savary, K. Schwean-Lardner and H. L. Classen University of Saskatchewan, Saskatoon, SK, Canada
Background Starch is the most important energy source in poultry Factors affecting rate and extent of starch digestion include: Size of the granule Degree of crystallinity Amylose:amylopectin ratio Encapsulation (Parada & Aguilera, 2011) http://polysac3db.cermav.cnrs.fr/
Starch classification RDS SDS RS Jejunum Energy source for ileum Fermentation Ileum Nutrient sensing Post-absorptive effects RDS: Rapidly digested starch SDS: Slowly digested starch RS: Resistant Starch (Englyst & Hudson, 1996) www.roysfarm.com
Energy source for ileum Normal Starch SDS L-Glutamate L-Glutamate L-Glutamate L-glu oxidation = Energy L-Glutamate L-glu + starch oxidation = Energy Theprojectopenwindow.com
Fermentation Protein Starch, fibre & sugar Microbial Fermentation Ammonia Volatile Fatty Acids Nocek & Russell, 1988; Sciencenews.org
Nutrient sensing Starch Inhibition Ileum Inhibition Nutrients E-dmj.org; youtube
Kidney Muscle Brain Glucose Adipose tissue Meal cv Intestine Engelking, 2011
Brain Kidney c v Muscle Glucose Intestine Adipose tissue
Glycemic index Plasma glucose RDS SDS Plasma insulin In Vitro In Vivo (Seal et al., 2003)
Poultry In vitro starch digestion (%) 100 80 60 40 20 RDS SDS 0 0 1 2 3 4 5 6 TIME (HR) Tapioca-Corn Pea-Corn (Weurding et al., 2003)
Feed:Gain (g/g) 1.63 Pea-Corn Tapioca-Corn 1.59 1.57 1.60 1.54 1.57 1.53 1.57 1.54 1.52 8.50 9.13 9.75 10.38 11.00 Digestible lysine content (g/kg) (Weurding et al., 2003)
Objective To determine the effects of starch digestibility rate and extent on the performance of broiler chickens and laying hens using semi purified starch sources Hypothesis Slowly or poorly digestive starch will result in more feed efficient broiler and egg production
Broiler Production Trial
Materials Starch sources Starch (%) Moisture (%) CP (%) Fibre (%) Fat (%) Ash (%) Wheat 92.50 7.00 0.30 0.10 0.06 0.00 Pea 80.00 5.78 6.31 1.71 0.89 0.95 Wheat Starch + Pea Protein = Pea Starch Starter diet 0 SDS 20 SDS 40 SDS 60 SDS 80 SDS 100 SDS Wheat Starch 51.74 41.39 31.04 20.69 7.24 0.00 Pea Starch 0.00 11.87 23.74 35.61 51.04 59.35 Pea Protein 7.61 6.09 4.57 3.05 1.07 0.00 Total starch 59.35 59.35 59.35 59.35 59.35 59.35
Methods 4500 Ross 308 broiler chickens 6 rooms of 12 floor pens/room (32 kg/m 2 ) RCBD: 6 diets x 2 gender blocked by room 0 20 40 60 80 100 Total Males 6 6 6 6 6 6 36 Females 6 6 6 6 6 6 36 Total 12 12 12 12 12 12 72 Duration: 31 days
Methods Data collection Dietary analysis Body weight Feed intake Mortality Meat yield SAS 9.3 Mixed model Regression analysis Significance level P < 0.05
Results In vitro digestibility (%) 100 90 80 70 60 50 40 30 0 20 40 60 80 100 15 30 45 60 90 120 180 240 Time (min)
Body weight gain (kg) 0-31 d 1.90 1.93 1.91 1.87 1.85 Ross 308 = 1.73 1.77 0 20 40 60 80 100 Linear regression P = 0.0016 (Quadratic response approached significance P = 0.0904)
Feed Intake (Kg) 0-31 d 2.98 2.93 2.92 Male Ross 308 = 2.74 2.89 2.85 2.91 2.61 2.64 2.67 Female Ross 308 = 2.47 2.62 2.63 2.67 0 20 40 60 80 100 Males Females M: Linear regression P = 0.0054 (Quad. P = 0.0555) F: No regression
Quadratic regression P = 0.0001 Feed efficiency (G:Fm) 0-31 d 0.70 0.69 Ross 308 = 0.68 0.69 0.68 0.68 0.64 0 20 40 60 80 100
Meat Yield
Meat Yield Live Weight 2.062 1.985 2.013 1.980 1.899 1.879 0 20 40 60 80 100 Linear regression P = 0.0046
Meat Yield Carcass weight (% of Live weight) 71.5 71.5 70.8 70.6 70.6 69.9 0 20 40 60 80 100 Quadratic regression approaches signific. P= 0.0814
Meat Yield Breast meat (% of Live weight) 20.2 20.3 20.0 20.4 20.3 19.3 0 20 40 60 80 100 Linear regression P = 0.0349
Meat Yield Breast skin (% of Live weight) 3.12 3.18 2.89 2.91 2.95 2.80 0 20 40 60 80 100 Linear regression P = 0.0096
Meat Yield Thigh meat (% of Live weight) 4.5 4.5 4.4 4.4 4.4 4.3 0 20 40 60 80 100 Quadratic regression P = 0.0234
Meat Yield Whole drum (% of Live weight) 4.8 4.8 4.8 4.7 4.7 4.7 0 20 40 60 80 100 Quadratic regression P = 0.0247
Meat Yield Drum skin (% of Live weight) 0.48 0.50 0.49 0.46 0.44 0.43 0 20 40 60 80 100 Linear regression P = 0.0022
0 20 40 60 80 100 Linear regression P = 0.0081 (Quad. Resp. approached significance P = 0.0987) Meat Yield Abdominal fat (% of Live weight) 0.809 0.746 0.607 0.660 0.585 0.650
Conclusion Low levels of SDS improved broiler performance Inclusion of SDS increased breast, thigh meat and whole drum yield Skin weight decreased as SDS inclusion increased Apparent shift in the allocation of resources from fat to muscle
Broilers vs. laying hens Age Development of digestive tract Microbial community Different feeding patterns
Laying Hen Production Trial
Materials & Methods 720 Lohmann LSL hens 26 weeks old Conventional cages (503 cm 2 /bird) Dietary treatments: 0, 20, 40, 60, 80 & 100 SDS Duration of the experiment: 20 weeks
Material & Methods Data collection Dietary analysis Feed intake Daily egg production Egg quality Body weight SAS 9.3 Mixed model Regression analysis Significance level P < 0.05
Body Weight (Kg) Lohmann LSL = 1.73 1.68 1.66 Lohmann LSL = 1.60 1.71 1.74 1.70 1.63 0 20 40 60 80 100 Quadratic regression P = 0.0021
Feed intake (g/hen per day) Lohmann LSL = 103.5 108.9 109.4 102.3 103.9 104.9 105.6 0 20 40 60 80 100 Linear regression P < 0.0001
Total hen day production (%) Lohmann LSL = 95.83 95.52 95.4 96.03 94.95 93.3 93.76 0 20 40 60 80 100 Linear regression P = 0.0102 (Quad. Reg. approached significance P = 0.0524)
Egg weight (g) Lohmann LSL = 60.70 59.49 59.46 59.88 59.73 59.64 59.63 0 20 40 60 80 100
Specific gravity 1.0835 1.0849 1.0861 1.0864 1.0858 1.0842 0 20 40 60 80 100 Quadratic regression P = 0.0004
Egg cracks (%) 0.11 0.12 0.10 0.12 0.07 0.08 0 20 40 60 80 100
Egg mass (g/hen housed) 1564.8 1571.8 1515.3 1535.1 1525.5 1541.5 0 20 40 60 80 100 Linear regression P = 0.0334
Feed efficiency (Feed g/egg mass) 1.91 1.94 1.85 1.87 1.84 1.86 0 20 40 60 80 100 Quadratic regression P = 0.0015
Conclusions Intermediate levels of SDS improved egg production Quadratic response for FCR mostly related to increased feed intake at high SDS levels No effects of SDS on egg weight or quality
Take home message Incorporation of low levels of starch sources in chicken diets with lower digestion rates and extent of digestion may result in better chicken performance
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