Producing ethanol from cereals for substitution of motor fuels is widely spread in the world. As a result, the process of cereal-based ethanol production yields a by-product, distillers dried grains with solubles (DDGS), which is available in rapidly increasing quantities as livestock feed. Product variability and lack of information about the nutritional value of DDGS from different sources, as well as the reduced amino acid (AA) digestibility and a AA pattern with low biological value, are reasons for the initial reluctance to use DDGS in diets for pigs and poultry (Nyachoti et al., 2005;Widyaratne and Zijlstra, 2007;Lan et al., 2008;Oryschak et al., 2010). Nevertheless, DDGS yet contains large quantities of nutrients and energy, respectively, including crude protein (CP) and nonphytate phosphorus; hence, it has the potential for being used as livestock feed especially for monogastrics (Nyachoti et al., 2005;Widyaratne and Zijlstra, 2007;Oryschak et al., 2010). An additional feature is the possible partial substitution of soybean meal and corn by DDGS and the regional production. As a result, the consumption of natural feed resources such as grains by pig and poultry feed can be considerably reduced without impairing the animals’ health or performance (Schedle, 2016). Above all, monogastric livestock or poultry directly compete with humans for feedstuffs/foodstuffs, because of their similar digestive physiology. Hence, the reduction of cereals in diets for monogastric livestock and poultry is very important from a sustainable point of view (Schedle, 2016).
The DDGS contains high amounts of fiber, mainly consisting of non-starch polysaccharides (NSP). However, composition of NSP can differ considerably in feed stuffs. Different kinds of NSP show various physiological actions in the gut (Montagne et al., 2003). The viscosity-increasing effect of NSP and their negative effects on digestion are well explained in literature (Hansen et al., 1992;Yin et al., 2000;Hogberg and Lindberg, 2004a, b). Supplementation of exogenous NSP-hydrolyzing enzymes to diets rich in NSP (e.g., from fiber-rich by-products such as DDGS) can, therefore, improve digestibility and subsequently the performance of monogastric animals (Emiola et al., 2009;Owusu-Asiedu et al., 2010).
Owing to the high amounts of fiber, the increase in DDGS demands an increase in dietary fat addition in the diet to keep the energy level constant (Thacker and Widyaratne, 2007;Schedle et al., 2010a). As the dietary fatty acid profile has a strong impact on energy, nitrogen, and fatty acid deposition in broiler chickens (Crespo and Esteve-Garcia, 2002), nutrient utilization as well as meat quality may be affected by increasing DDGS contents in broiler diets.
In this context, a study was conducted to determine the applicability of a wheat-corn-DDGS as protein source with and without NSP-hydrolyzing enzymes in diets for broiler chicks. Furthermore, effect on energy parameters (energy intake per day, energy per kilogram feed), digestibility of dry matter, apparent N retention, as well as sensory aspects and fatty acid balance of breast meat were determined.
In total, 360 one-day-old Ross 308 chickens were purchased from a commercial hatchery (Helmut Wohlin, Klagenfurt, Austria). Considering initial body weight (BW), one-day-old chicks were distributed equally among 24 pens of 3 m2 and six dietary treatments (four replicates, 15 birds per pen). Animals were housed in the poultry trial station of the institute (Wimitz, Austria). Each of the 24 pens was equipped with wood shavings as litter material, an automatic waterer, infrared warming lamp, and size-adjusted feed troughs. Mash feed and water were offered
The trial was divided into starter (day 1–14), grower (day 14–28), and finisher (day 28–36) period. Starter (12.4 AMEN kg−1; 22.0% CP), grower (12.8 AMEN kg−1; 21.0% CP), and finisher (12.7 AMEN kg−1; 20.0% CP) diets were mainly based on corn and soybean meal. Experimental diets (Table 1) were formulated to contain rising amounts of DDGS at the expense of corn and soybean meal. Thus, DDGS originating from wheat and corn was included into the diet at 8%, 16%, and 24% levels. Wheat-corn-DDGS (wheat-to-corn ratio: 44:56) was obtained from an Austrian bioethanol plant (AGRANA, Pischelsdorf, Austria). Analyzed composition of the DDGS (as-fed basis) is given in Table 2. Digestibility values for DDGS were taken from Kluth and Rodehutscord (2010). To improve ethanol extraction, hydrolyzing enzymes of the categories endopeptidases (IUB number 3.4.23.18), cellulases (IUB number 3.2.1.4), β-glucanases (IUB number 3.2.1.6), α-amylases (IUB number 3.2.1.1), and gluco-amylases (IUB number 3.2.1.3) were added in the production process of the applied DDGS. Aliquots of the three DDGS basal diets (8%, 16%, and 24% DDGS) were supplemented with an NSP-hydrolyzing enzyme (Roxazyme G2G, DSM Nutritional Products Ltd, Basel, Switzerland) using a dose of 200 ppm. The enzyme dose was carefully blended with a portion of the diet before being mixed with the entire feed mix. The NSP-hydrolyzing product is stated by the manufacturer as providing major activities of cellulase, β-glucanase, and xylanase. NSP-hydrolyzing enzyme was added on top without taking the potential energy contribution into account. Titanium dioxide (0.25%) was added to all finisher diets as an indigestible marker. Experimental diets within each growth phase were formulated to contain similar concentrations of total AMEN, digestible (d) lysine (1.16% starter, 1.05% grower, and 0.86% finisher), d methionine (0.44% starter, 0.42% grower, and 0.37% finisher), and d threonine (0.73% starter, 0.68% grower, and 0.62% finisher). To achieve isocaloric conditions, the fat content in the diets was increased linearly with rising DDGS concentration, applying a blend of vegetable oils (Unifrutol®, Garant, Pöchlarn, Austria).
Composition (%) of the experimental diets
Tabelle 1. Zusammensetzung (%) der Versuchsfuttermischungen
Star terdiet | Grower diet | Finisher diet | |||||||
---|---|---|---|---|---|---|---|---|---|
% DDGS | 8 | 16 | 24 | 8 | 16 | 24 | 8 | 16 | 24 |
Feed components, % | |||||||||
Wheat-corn-DDGS | 8.00 | 16.00 | 24.00 | 8.00 | 16.00 | 24.00 | 8.00 | 16.00 | 24.00 |
Soybean meal | 33.41 | 28.50 | 23.60 | 31.04 | 26.13 | 21.23 | 23.74 | 18.84 | 13.93 |
Corn | 50.29 | 46.53 | 42.77 | 51.41 | 47.65 | 43.88 | 57.99 | 54.27 | 50.53 |
Corn gluten | - | - | - | - | - | - | 3.00 | 3.00 | 3.00 |
Vegetable oil Unifrutol®, Garant, Pöchlarn, Austria | 5.05 | 5.67 | 6.29 | 6.48 | 7.10 | 7.71 | 4.60 | 5.22 | 5.84 |
Feed lime | 1.288 | 1.411 | 1.534 | 1.134 | 1.257 | 1.381 | 1.184 | 1.307 | 1.431 |
Dicalcium phosphate | 1.137 | 0.969 | 0.801 | 1.207 | 1.038 | 0.870 | 0.991 | 0.822 | 0.654 |
Salt | 0.226 | 0.180 | 0.134 | 0.277 | 0.182 | 0.136 | 0.230 | 0.184 | 0.138 |
Vitamin premix One kilogram of vitamin premix includes 40,000,000 IU vitamin A, 16,500,000 IU vitamin D, 165,000 mg vitamin E, 13,500 mg vitamin K, 10,000 mg vitamin B1, 25,000 mg vitamin B2, 15,000 mg vitamin B6, 75 mg vitamin B12, 230,000 mg nicotinic acid, 65,000 mg pantothenic acid, 6,500 mg folic acid, 400 mg biotin | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 |
Trace element premix One kilogram of trace element premix includes 120 g Fe, 120 g Zn, 180 g Mn, 30 g Co, 2 g I, 2 g Co, 0.8 g Se | 0.056 | 0.056 | 0.056 | 0.056 | 0.056 | 0.056 | 0.056 | 0.056 | 0.056 |
L-lysine | 0.203 | 0.311 | 0.418 | 0.137 | 0.245 | 0.352 | 0.040 | 0.147 | 0.254 |
DL-methionine | 0.145 | 0.145 | 0.144 | 0.136 | 0.136 | 0.135 | 0.072 | 0.071 | 0.070 |
L-threonine | 0.020 | 0.049 | 0.078 | 0.049 | 0.034 | 0.063 | 0.000 | 0.000 | 0.016 |
Cholin-Cl | 0.080 | 0.080 | 0.080 | 0.080 | 0.080 | 0.080 | 0.040 | 0.040 | 0.040 |
Elancoban | 0.050 | 0.050 | 0.050 | 0.050 | 0.050 | 0.050 | - | - | - |
Loxidan | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 |
ZY-Phytase | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 | 0.010 |
Titanium dioxide | - | - | - | - | - | - | 0.25 | 0.25 | 0.25 |
Analyzed nutrient and amino acid content of the experimental diets and DDGS (in g kg−1 as fed)
Tabelle 2. Analysierte Nährstoff- und Aminosäurengehalte der Versuchsfuttermischungen sowie der Trockenschlempe (DDGS) (in g kg−1 Frischmasse)
Starterdiet | Growerdiet | Finisherdiet | DDGS | |||||||
---|---|---|---|---|---|---|---|---|---|---|
%DDGS | 8 | 16 | 24 | 8 | 16 | 24 | 8 | 16 | 24 | |
DM | 908 | 914 | 907 | 899 | 898 | 900 | 895 | 896 | 906 | 926 |
AMEN, MJ kg−1 Calculated according to GfE (1999) | 12.8 | 12.7 | 12.6 | 13.3 | 13.2 | 12.9 | 13.0 | 12.9 | 12.8 | 8.8 |
CP | 235 | 234 | 230 | 215 | 217 | 216 | 201 | 202 | 206 | 322 |
EE | 75 | 83 | 95 | 90 | 99 | 105 | 77 | 85 | 95 | 90 |
Ash | 53 | 53 | 55 | 53 | 52 | 51 | 49 | 49 | 54 | 58 |
Starch | 355 | 339 | 316 | 375 | 351 | 327 | 408 | 383 | 360 | 45 |
Sugar | 47 | 44 | 39 | 45 | 41 | 37 | 33 | 33 | 28 | 26 |
NDF | 152 | 170 | 194 | 149 | 180 | 200 | 147 | 168 | 201 | 478 |
ADF | 52 | 62 | 68 | 63 | 60 | 68 | 58 | 56 | 67 | 179 |
Lys | 14.9 | 15.0 | 15.4 | 13.6 | 13.9 | 13.4 | 10.7 | 10.3 | 10.0 | 8.2 |
Met | 4.7 | 5.2 | 4.5 | 4.6 | 4.6 | 4.6 | 3.7 | 3.8 | 3.9 | 4.9 |
Cys | 3.7 | 3.9 | 3.7 | 3.5 | 3.7 | 3.8 | 3.4 | 3.5 | 3.6 | 5.9 |
Thr | 8.3 | 8.4 | 7.8 | 7.5 | 7.4 | 7.5 | 7.1 | 6.7 | 6.6 | 10.1 |
Trp | 2.6 | 2.5 | 2.4 | 2.4 | 2.2 | 2.3 | 2.0 | 2.0 | 1.9 | 3.2 |
Val | 10.2 | 10.1 | 9.3 | 9.5 | 9.1 | 9.4 | 8.9 | 8.6 | 8.6 | 14.4 |
Ile | 9.2 | 8.9 | 8.0 | 8.4 | 8.0 | 8.1 | 7.9 | 7.4 | 7.2 | 11.6 |
Leu | 18.1 | 17.8 | 16.4 | 16.4 | 16.1 | 16.3 | 17.9 | 17.4 | 17.4 | 24 |
Arg | 14.8 | 14.1 | 11.9 | 13.5 | 12.5 | 12.0 | 11.8 | 11.1 | 10.0 | 13.7 |
Ca | 8.6 | 9.1 | 9.3 | 8.7 | 8.7 | 9.1 | 7.8 | 8.0 | 8.2 | 1.5 |
P | 5.9 | 5.9 | 6.1 | 6.0 | 6.0 | 6.1 | 5.4 | 5.3 | 5.4 | 9.6 |
Na | 0.9 | 1.2 | 1.4 | 1.1 | 1.2 | 1.4 | 1.0 | 1.2 | 1.3 | 5.9 |
Feed samples were obtained from each batch of feed, vacuum packed and stored at −20 °C until analysis. All diets were analyzed for dry matter (DM), ash, CP, ether extracts (EE), starch, sugar, neutral detergent fiber (NDF), and acid detergent fiber (ADF) according to standard procedures (Naumann and Bassler, 2012). AA composition was analyzed by applying the methods of Altmann (1992). P was determined photometrically (U5100-Spectrophotometer-Hitatchi, Metrohm, Vienna, Austria) using the vanadomolybdate method to measure color intensity at 436 nm after wet ashing of feed samples in HNO3 and H2O2 via microwave (MLS-ETHOS plus Terminal 320, Leutkirch, Germany). Ca and Na were determined by flame atomic absorption spectrophotometry (AAnalyst 200, Perkin Elmer, Brunn am Gebirge, Austria). The concentration of TiO2 was determined photometrically following sulfuric acid digestion, as described by Jagger et al. (1992). An adiabatic oxygen bomb calorimeter (IKA-C400, Staufen, Germany) was used to determine the gross energy (GE). Broiler chickens’ BW and feed consumption were evaluated per pen on days 1, 14, 28, and 36. Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were calculated for the starter, grower, finisher, and the whole fattening period.
On days 32 and 33 of fattening, clean excreta (free from feathers and feed) were collected twice daily from steel liners placed in the collection trays underneath each pen of birds. The excreta from the four collections from each cage were pooled and then frozen for storage. Nitrogen and DM content (Naumann and Bassler, 2012) was determined in thawed digesta. Before the analysis of GE (Naumann and Bassler, 2012) and TiO2 (Jagger et al., 1992), the samples were freeze dried (TELSTAR LyoBeta 15, Terrassa, Spain), followed by grinding.
After analysis, the energy lost in excreta was determined and the AMEN was calculated as follows: AMEN (kJ kg − 1 of diet) = GEdiet − [GEexcreta × (markerdiet /markerexcreta ) − 34.42 × (Ndiet − Nexcreta × (markerdiet /markerexcreta ))] where GE is the gross energy [kJ kg−1 of sample (diet, excreta)] and marker is the concentration of TiO2 (Hill and Anderson, 1958;GfE, 1999).
At the end of the experiment, broilers were stunned and killed by bleeding in the slaughter house of the poultry trial station. At the day of slaughter and the subsequent day, dressing, eviscerated carcass (weight of the slaughtered animals without blood, feathers, uropygial gland, viscera, abdominal fat, and giblets), chilled carcass (weight of eviscerated carcass after 16-h storage in a cooling chamber at +3 ° C), carcass for grilling (weight of chilled carcass without head and neck and legs at the hock joints), and giblets (weight of empty gizzard, liver without gall bladder and heart immediately after slaughter) were assessed.
From 72 representing broilers (6 male and 6 female per treatment), whole bone-less breast meat samples were removed 24-h post mortem and stored at −20 °C until analyses.
For the sensory analysis of chicken breast meat, a consumer-based sensory panel of six testing persons experienced in sensory evaluation was used. Chicken breasts were thawed to 2 °C for 24 h before sensory testing. Untreated 1-cm thick breast meat pieces were grilled well-done for 4 min on each side in individual dishes at maximum power (Raclette Gourmet Grill Deluxe, Tefal S.A.S., Rumilly, France). Water and unsalted crackers were provided, and panelists were asked to expectorate and rinse their mouths between each sample. Each panelist was asked to evaluate six coded chicken breast samples per session (i.e., 12 sessions in total, performed on 2 days), one sample from each treatment, for tenderness, juiciness, and flavor, using a six-point hedonic scale, in which 1 = very tough/very dry/dislike extremely and 6 = very tender/very juicy/like extremely.
Chemical analyses in meat samples: The remaining raw breast meat samples without skin were freeze dried to determine the DM content. Subsequently, lyophilized meat samples were homogenized and the amount of CP and EE was analyzed by applying standard methods (Naumann and Bassler, 2012). For the determination of fatty acid profile, the one-step methylation method by Sukhija and Palmquist (1988) was applied. Briefly, 0.5 g of freeze-dried meat samples was extracted and converted to methyl esters for 2 h at 70 °C with toluene and 5% fresh methanolic HCl using nonadecanoic acid (C19:0, Sigma Aldrich, Munich, Germany) as internal standard. Subsequently, 5 ml of 6% K2CO3 was added followed by another 2 ml of toluene. After centrifugation, 1 μl of the organic layer (split 50:1) was analyzed on a gas chromatograph (Agilent Technologies 7890A, Waldbronn, Germany) equipped with an automatic sampler 7693, an Agilent HP-88 capillary column (100 m × 0.25 mm of internal diameter and 0.2 μm film thickness), and flame ionization detector (FID). The flow rates of the carrier gases (hydrogen and synthetic air) were 35 and 350 ml min−1, respectively. Conditions: The injection port temperature and the detection temperature were 250 °C. Oven temperature was ramped to 170 °C for 1 min followed by an increase to 200 °C at 2 °C min−1. After 1 min at 200 °C, temperature was increased by 8 °C min−1 to 230 °C, which was held for another 10 min. Commercial standard fatty acid methyl esters (FAME) mixtures (Supelco 37 Component FAME Mix, Supelco, Pennsylvania, USA) were used for the identification of individual fatty acids.
All experimental data were statistically analyzed by the general linear model (GLM) procedure of SAS 9.1.3 (SAS, Inst., Inc., Cary, NC, USA) by applying the following model: yijk = μ + αi + βj + α*βij + eijk (yijk is the dependent variable, μ is the overall mean, αi the effect of DDGS concentration (i = 1, 2, 3), βj is the effect of NSP-hydrolyzing enzyme supplementation (j = 1, 2), α *βij is the effect of interaction of DDGS concentration and NSP-hydrolyzing enzyme supplementation, eijk is the residual experimental error). Treatment effects were determined by analysis of variance (ANOVA) using the Tukey–Kramer test in case of a significant interaction. For performance, energy parameters, and digestibility, the pen served as experimental unit, whereas for carcass characteristics and meat quality parameters, the individual animal was the experimental unit. Tables 4–9 present the least squares (LS)-mean (except for organoleptic parameters, where means were used) values of the different dietary treatments and the pooled standard error of means (SEM). For the statistical evaluation of the organoleptic tests, the Wilcoxon range test was applied. Significant differences among means (
Analyzed nutrient concentrations of starter, grower, and finisher diets are presented in Table 2. The results of fatty acid profile of the diets as well as the applied pure DDGS and vegetable oil are presented in Table 3. On an average, the EE content and accordingly the absolute amount of fatty acids increased by 9% and 30%, with the dietary rise in DDGS to 16% and 24% (and concomitant oil supplementation), respectively, compared to diet DDGS 8%. Values were within the expected range.
Analyzed fatty acid profile of the diets, the pure DDGS, and vegetable oil (g/kg as fed)
Tabelle 3. Analysiertes Fettsäuremuster der Versuchsfuttermischungen, der Trockenschlempe (DDGS) und des Futterfettes (g/kg Frischmasse)
Starter diet | Grower diet | Finisher diet | DDGS Wheat-corn-DDGS (Agrana, Pischelsdorf, Austria) | Oil Unifrutol® (Garant, P öchlarn, Austria) | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
%DDGS | 8 | 16 | 24 | 8 | 16 | 24 | 8 | 16 | 24 | ||
SFA SFA is the sum of saturated fatty acids (C12:0 + C14:0 + C16:0 + C18:0 + C20:0) | 16.16 | 17.78 | 20.08 | 19.73 | 21.98 | 24.01 | 16.11 | 17.57 | 21.27 | 13.54 | 107.49 |
MUFA MUFA is the sum of monounsaturated fatty acids (C16:1 + C18:1n9 + C18:1n7 + C20:1) | 23.68 | 26.04 | 30.28 | 29.57 | 30.69 | 29.73 | 20.71 | 21.71 | 26.20 | 11.16 | 342.41 |
PUFA PUFA is the sum of polyunsaturated fatty acids (C18:2 + C18:3n3) | 31.08 | 34.75 | 40.06 | 36.45 | 40.30 | 44.81 | 32.44 | 35.11 | 42.54 | 35.40 | 419.66 |
PUFA:SFA | 1.92 | 1.95 | 1.99 | 1.85 | 1.83 | 1.87 | 2.01 | 2.00 | 2.00 | 2.62 | 3.90 |
C12:0 | 0.81 | 0.90 | 1.09 | 1.15 | 1.76 | 3.60 | 2.11 | 2.30 | 2.84 | 1.68 | 9.26 |
C14:0 | 0.41 | 0.47 | 0.57 | 0.57 | 0.79 | 1.37 | 0.79 | 0.87 | 1.09 | 0.07 | 4.11 |
C16:0 | 10.26 | 11.58 | 13.35 | 12.47 | 13.82 | 13.72 | 9.48 | 10.41 | 12.65 | 10.47 | 68.89 |
C16:1 | 1.28 | 1.02 | 0.94 | 1.10 | 0.95 | 1.32 | 1.16 | 0.83 | 0.60 | 0.18 | n.d. n.d., not detected |
C18:0 | 2.82 | 3.06 | 3.54 | 3.47 | 3.92 | 4.34 | 2.75 | 2.92 | 3.64 | 1.04 | 25.24 |
C18:1n9 | 20.99 | 23.45 | 27.51 | 26.75 | 27.95 | 26.80 | 18.46 | 19.70 | 24.16 | 10.00 | 325.00 |
C18:1n7 | 1.16 | 1.27 | 1.48 | 1.42 | 1.46 | 1.30 | 0.88 | 0.95 | 1.14 | 0.66 | 17.41 |
C18:2 | 29.18 | 32.65 | 37.63 | 34.18 | 38.00 | 42.73 | 30.99 | 33.51 | 40.65 | 33.24 | 388.57 |
C18:3n3 | 1.90 | 2.10 | 2.42 | 2.27 | 2.31 | 2.08 | 1.45 | 1.60 | 1.90 | 2.16 | 31.09 |
C20:0 | 0.29 | 0.32 | 0.36 | 0.35 | 0.38 | 0.35 | 0.25 | 0.26 | 0.33 | 0.14 | n.d. |
C20:1 | 0.25 | 0.29 | 0.35 | 0.31 | 0.34 | 0.31 | 0.21 | 0.23 | 0.30 | 0.31 | n.d. |
Unlike the results of Heincinger et al. (2012), in which the relative amount of dietary linoleic acid increased by 5.1% when increasing DDGS content by 15% (replacing soybean-meal and wheat), increases from 8% DDGS to 24% DDGS in our study only resulted in a relative increase of 0.9% in finisher diet (data not shown).
The performance results of broilers during the experimental period are shown in Table 4. Starting with homogeneous distribution of BWs, BW, ADG, and ADFI did not differ among treatment groups (
Zootechnical performance of broiler chicks
Tabelle 4. Zootechnische Leistungen der Broiler
DDGS | NSP enzyme | SEM | |||||||
---|---|---|---|---|---|---|---|---|---|
8 | 16 | 24 | − | + | DDGS | Enzyme | DDGS × Enzyme | ||
Fattening performance day 1–14 (starterphase) | |||||||||
BW, day 1, g | 43.1 | 43.1 | 43.1 | 43.1 | 43.1 | 0.07 | 0.986 | 0.812 | 0.939 |
BW, day 14, g | 430.4 | 442.7 | 435.8 | 435.3 | 437.4 | 3.77 | 0.522 | 0.808 | 0.876 |
ADG, g day−1 | 26.5 | 28.3 | 27.3 | 27.5 | 27.3 | 0.34 | 0.149 | 0.741 | 0.744 |
ADFI, g day−1 | 36.2 | 37.0 | 35.9 | 36.8 | 35.9 | 0.33 | 0.462 | 0.209 | 0.714 |
FCR, g g−1 | 1.37(a) | 1.31(b) | 1.32(ab) | 1.34 | 1.32 | 0.01 | 0.044 | 0.239 | 0.856 |
Fattening performance day 14–28 (grower phase) | |||||||||
BW, day 28, g | 1,404 | 1,448 | 1,408 | 1,402 | 1,439 | 11.5 | 0.244 | 0.125 | 0.587 |
ADG, g day−1 | 69.2 | 71.8 | 69.3 | 69.0 | 71.2 | 0.66 | 0.212 | 0.099 | 0.643 |
ADFI, g day−1 | 112.6 | 115.3 | 112.2 | 113.7 | 113.1 | 0.89 | 0.303 | 0.723 | 0.617 |
FCR, g g−1 | 1.63 | 1.61 | 1.62 | 1.65 | 1.59 | 0.01 | 0.761 | 0.016 | 0.824 |
Fattening performance day 28–36 (finisher phase) | |||||||||
BW, day 36, g Individual instead of pen-wise determination of BW | 2,078 | 2,118 | 2,059 | 2,059 | 2,111 | 14.4 | 0.240 | 0.044 | 0.176 |
ADG Interaction DDGS × enzyme: DDGS 8% enzyme −: 80.5b g; DDGS 8% enzyme +: 90.1a g; DDGS 16% enzyme −: 84.3ab g; DDGS 16% enzyme +: 84.4ab g; DDGS 24% enzyme −: 81.4b g; DDGS 24% enzyme +: 82.9b g | 85.3 | 84.3 | 82.2 | 82.1 | 85.8 | 0.86 | 0.104 | 0.005 | 0.008 Interaction DDGS × enzyme: DDGS 8% enzyme −: 80.5b g; DDGS 8% enzyme +: 90.1a g; DDGS 16% enzyme −: 84.3ab g; DDGS 16% enzyme +: 84.4ab g; DDGS 24% enzyme −: 81.4b g; DDGS 24% enzyme +: 82.9b g |
ADFI, g day−1 | 167.9 | 171.1 | 168.4 | 166.9 | 171.4 | 1.31 | 0.500 | 0.074 | 0.386 |
FCR Interaction DDGS × enzyme: DDGS 8% enzyme −: 2.03a g g−1; DDGS 8% enzyme +: 1.91b g g−1; DDGS 16% enzyme −: 2.02a(b) g g−1; DDGS 16% enzyme +: 2.04a g g−1; DDGS 24% enzyme −: 2.06a g g−1; DDGS 24% enzyme +: 2.04a g g−1 | 1.97b | 2.03a(b) | 2.05a | 2.03 | 2.00 | 0.02 | 0.015 | 0.074 | 0.025 Interaction DDGS × enzyme: DDGS 8% enzyme −: 2.03a g g−1; DDGS 8% enzyme +: 1.91b g g−1; DDGS 16% enzyme −: 2.02a(b) g g−1; DDGS 16% enzyme +: 2.04a g g−1; DDGS 24% enzyme −: 2.06a g g−1; DDGS 24% enzyme +: 2.04a g g−1 |
Fattening performance day 1–36 | |||||||||
ADG, g day−1 | 54.7(b) | 57.2(a) | 55.1(ab) | 55.1 | 56.3 | 0.47 | 0.073 | 0.197 | 0.911 |
ADFI, g day−1 | 93.1 | 96.5 | 94.2 | 94.5 | 94.6 | 0.75 | 0.162 | 0.946 | 0.882 |
FCR, g g−1 | 1.66 | 1.75 | 1.77 | 1.75 | 1.70 | 0.01 | 0.749 | 0.733 | 0.221 |
Our results show that an increasing DDGS content had no effect on ADG, ADFI, and FCR during the whole fattening period, provided that a sufficient supply with digestible amino acids (dAA) to cover requirements is warranted. Other studies based on the similar study design confirm the present observations (Oryschak et al., 2010). Nevertheless, other authors reported decreases in ADG and ADFI by increasing DDGS content (Lumpkins et al., 2004, Schedle et al., 2010a). A possible reason for the decline in performance of those studies might be the formulation of AA on basis of total AA without consideration of their digestibility (Whitney and Shurson, 2004).
Raising amounts of DDGS by expense of corn and soybean meal enhances the NSP content in feed (Widmer et al., 2008;Schedle et al., 2010b). Supplementation of NSP-degrading enzymes to diets containing high amounts of NSP or rather fiber is of interest to increase the potential for use of fiber-rich industrial by-product such as DDGS in the diet of monogastric animals (Zijlstra et al., 2010). In the present study, enzyme supplementation led to an enhanced ADG in the finisher phase and final BW. Additionally, the NSP-hydrolyzing enzyme complex improved FCR in the grower (
No differences between treatments were detected regarding the AMEN content of diets (Table 5). The energy content reached 11.5 MJ AMEN kg−1, on an average. Nevertheless, these values are lower than the calculated energy contents. Similar effects were observed for the parameters energy intake per day and energy/gain. Neither DDGS nor enzyme supplementation affected N retention and total tract apparent retention of DM.
Energy parameters, apparent N retention, and DM digestibility in finisher phase
Tabelle 5. Energieparameter, N-Retention und Trockenmasseverdaulichkeit in der Finisherphase
DDGS | NSPenzyme | SEM | |||||||
---|---|---|---|---|---|---|---|---|---|
8 | 16 | 24 | − | + | DDGS | Enzyme | DDGS × Enzyme | ||
GrossEnergy, kJ/kgDM | 19,284 | 19,477 | 19,818 | ||||||
Energy, kJ AMEN kg−1 feed as-fed Calculated according to Hill and Anderson (1958) and GfE (1999) | 11,480 | 11,402 | 11,713 | 11,507 | 11,556 | 332 | 0.494 | 0.828 | 0.535 |
Energyintake, kJ AMEN day−1 | 1,927 | 1,949 | 1,972 | 1,919 | 1,980 | 55 | 0.647 | 0.138 | 0.759 |
Energy/gain, kJ kg−1 | 22,658 | 23,132 | 24,034 | 23,439 | 23,111 | 574 | 0.159 | 0.569 | 0.149 |
ApparentNretention,% | 52.06 | 45.06 | 50.07 | 46.29 | 51.84 | 0.854 | 0.386 | 0.199 | 0.649 |
Digestibility of DM,% | 67.23 | 65.31 | 65.66 | 65.49 | 66.65 | 0.374 | 0.387 | 0.341 | 0.552 |
The replacement of soybean meal and corn by dietary DDGS inclusion demands an increase in vegetable oil addition in the broiler diet to keep the energy level constant (Thacker and Widyaratne, 2007;Schedle et al., 2010a). It is well known that increasing oil levels, altered oil/fat composition of diets, as well as fiber content can affect nutrient digestibility in broilers. This may result from alteration in transit time, mucosal architecture, and activity of digestive enzymes, especially proteases (Ketels and DeGrote, 1989;Jiménez-Moreno et al., 2009;Honda et al., 2010). However, AMEN content, DM digestibility, and apparent N retention did not differ between treatments. Similar observations were made by Crespo and Esteve-Garcia (2002). Other authors reported a decrease in protein digestibility by increasing oil content (Leytem et al., 2008;Honda et al., 2010). The dietary fatty acid profile has a strong impact on energy, nitrogen, and fatty acid deposition in broiler chickens (Crespo and Esteve-Garcia, 2002). Hence, both the increase in dietary oil and the concomitant raise in unsaturation of dietary fatty acids might be a reason for the unaltered apparent N retention in the finisher phase of our study.
Furthermore, Oryschak et al. (2010) found interactions between triticale DDGS and NSP-hydrolyzing enzymes in broiler diets. In their study, apparent ileal digestibility of CP and several AA increased with enzyme supplementation in diets containing 15% DDGS but not in diets with 30% DDGS inclusion. The difference between the treatments with and without enzyme in the low DDGS diet (8%) in our study might indicate an improved effect of the enzyme on the non-DDGS diet components in our study. The inclusion of similar NSP-degrading enzymes in the production process of the applied DDGS product may be an explanation for the absence of distinct effects of the NSP-hydrolyzing enzyme supplemented in the diet on performance in high DDGS groups.
Carcass characteristics are shown in Table 6. Diets containing 16% DDGS had significantly higher dressing percentage compared to treatments with 8% DDGS (
Results of carcass parameters and dividing chilled carcasses into carcass parts
Tabelle 6. Ergebnisse der Schlachtleistung sowie der Teilstückanalyse
DDGS | NSP enzyme | SEM | |||||||
---|---|---|---|---|---|---|---|---|---|
8 | 16 | 24 | − | + | DDGS | Enzyme | DDGS } Enzyme | ||
Carcassparameters | |||||||||
Dressing, % | 78.1b | 78.7a | 78.4ab | 78.4 | 78.4 | 0.08 | 0.006 | 0.640 | 0.064 |
Evisceratedcarcass, g | 1627.4 | 1666.1 | 1613.9 | 1616.5 | 1655.1 | 11.92 | 0.110 | 0.070 | 0.098 |
Chilledcarcass, g | 1605.6 | 1643.9 | 1592.0 | 1594.5 | 1633.3 | 11.74 | 0.104 | 0.064 | 0.086 |
Carcassforgrilling, g | 1447.6 | 1481.7 | 1432.8 | 1435.6 | 1472.4 | 10.75 | 0.108 | 0.062 | 0.080 |
Abdominal fat, g | 34.5 | 36.0 | 35.0 | 34.9 | 35.4 | 0.51 | 0.483 | 0.584 | 0.442 |
Heart Interaction DDGS } enzyme: DDGS 8% enzyme −: 9.17b g; DDGS 8% enzyme +:9.88a g; DDGS 16% enzyme −: 9.45ab g; DDGS 16% enzyme +: 9.30ab g; DDGS 24% enzyme −: 9.21a(b) g; DDGS 24% enzyme +: 9.44ab g | 9.53 | 9.38 | 9.33 | 9.28 | 9.54 | 0.08 | 0.456 | 0.054 | 0.034 |
Liver Interaction DDGS } enzyme: DDGS 8% enzyme−: 39.9b g; DDGS 8% enzyme +: 47.3a g; DDGS 16% enzyme −: 42.3b g; DDGS 16% enzyme +: 41.8b g; DDGS 24% enzyme −: 41.6b g; DDGS 24% enzyme +: 42.0b g | 43.6 | 42.1 | 41.8 | 41.3 | 43.7 | 0.39 | 0.100 | 0.001 | <0.001 |
Gizzard, g | 25.4b | 26.3ab | 26.6a | 26.0 | 26.2 | 0.21 | 0.042 | 0.588 | 0.559 |
Relativeproportion(%)ofcarcasspartscomparedtothecarcassforgrilling | |||||||||
Breast | 27.5 | 27.6 | 28.4 | 27.8 | 28.0 | 0.266 | 0.181 | 0.649 | 0.623 |
Legs | 27.7 | 28.5 | 28.4 | 28.5 | 27.9 | 0.226 | 0.213 | 0.127 | 0.803 |
Wings | 10.9 | 10.5 | 10.5 | 10.6 | 10.7 | 0.101 | 0.184 | 0.568 | 0.291 |
Remainderofcarcass | 33.8a | 33.2ab | 32.2b | 33.0 | 33.1 | 0.233 | 0.009 | 0.732 | 0.623 |
Increasing DDGS and vegetable oil contents had no influence on crude nutrient contents of raw breast meat (Table 7). However, enzyme addition resulted in a significant reduction of EE and a concomitant increase in CP (% DM). Thus, enzyme addition resulted in less intramuscular fat content in breast meat, indicating a potentially preferential utilization of dietary energy for protein retention. However, while apparent N retention was only numerically increased with enzyme addition, CP (%DM) content in breast meat was significantly higher (
Crude nutrient content of breast meat samples without skin (% DM)
Tabelle 7. Rohnährstoffgehalte der Brustfleischproben ohne Haut (% Trockenmasse)
DDGS | NSP enzyme | SEM | |||||||
---|---|---|---|---|---|---|---|---|---|
8 | 16 | 24 | − | + | DDGS | Enzyme | DDGS × Enzyme | ||
DM | 24.82 | 24.90 | 24.63 | 24.82 | 24.75 | 0.08 | 0.361 | 0.640 | 0.734 |
CP | 86.88 | 86.44 | 87.12 | 86.34 | 87.28 | 0.23 | 0.489 | 0.046 | 0.590 |
EE | 4.45 | 4.81 | 4.45 | 4.89 | 4.25 | 0.15 | 0.527 | 0.033 | 0.834 |
DM, dry matter; CP, crude protein; EE, ether extract
In this respect, sensory analyses showed a trend of high DDGS diets to increase meat tenderness (
Results of the organoleptic testing panel
Tabelle 8. Organoleptische Untersuchung der Brustfleischproben
DDGS | NSP enzyme | SEM | ||||||
---|---|---|---|---|---|---|---|---|
8 | 16 | 24 | − | + | DDGS | Enzyme | ||
Tenderness Based on a six-point hedonic scale: 1 = very tough/very dry/dislike extremely and 6 = very tender/very juicy/like extremely | 4.21(b) | 4.24(b) | 4.52(a) | 4.39 | 4.26 | 0.06 | 0.053 | 0.295 |
Juiciness Based on a six-point hedonic scale: 1 = very tough/very dry/dislike extremely and 6 = very tender/very juicy/like extremely | 3.98 | 4.01 | 4.19 | 4.16 | 3.96 | 0.06 | 0.306 | 0.074 |
Flavor Based on a six-point hedonic scale: 1 = very tough/very dry/dislike extremely and 6 = very tender/very juicy/like extremely | 3.39 | 3.63 | 3.32 | 3.49 | 3.40 | 0.06 | 0.190 | 0.413 |
The influence of DDGS and vegetable oil on fatty acid composition (Table 9) was primarily seen in a significant increase in the amount of polyunsaturated fatty acids (PUFAs) in a linear manner. Furthermore, the significant increase in PUFA-to-saturated fatty acid (SFA) ratio shows that this increase goes along with a significant decrease in SFA (
Fatty acid profile of breast meat samples without skin (% FAME)
Tabelle 9. Fettsäuremuster der Brustfleischproben ohne Haut (% Fettsäuremethylester)
DDGS | NSP enzyme | SEM | |||||||
---|---|---|---|---|---|---|---|---|---|
8 | 16 | 24 | − | + | DDGS | Enzyme | DDGS × Enzyme | ||
SFA | 30.29(a) | 29.61(b) | 29.65(b) | 29.74 | 29.96 | 0.12 | 0.033 | 0.354 | 0.799 |
MUFA | 35.84a(b) | 34.81(b) | 32.23c | 34.80 | 33.79 | 0.27 | <0.0001 | 0.011 | 0.894 |
PUFA | 33.94c | 35.76b | 38,35a | 35.52 | 36.51 | 0.28 | <0.0001 | 0.004 | 0.973 |
n3 | 1.98(ab) | 1.91(b) | 2.04(a) | 1.95 | 2.00 | 0.02 | 0.098 | 0.248 | 0.455 |
n6 | 31.91c | 33.67b | 36.31a | 33.54 | 34.39 | 0.27 | <0.0001 | 0.010 | 0.886 |
n6:n3 | 16.21b | 17.69a | 18.04a | 17.35 | 17.28 | 0.18 | <0.0001 | 0.837 | 0.297 |
PUFA:SFA | 1.13c | 1.20b | 1.29a | 1.20 | 1.22 | 0.01 | <0.0001 | 0.215 | 0.998 |
C12:0 | 0.58c | 0.75b | 1.02a | 0.80 | 0.77 | 0.03 | <0.0001 | 0.386 | 0.731 |
C14:0 | 0.71c | 0.79b | 0.91a | 0.82 | 0.78 | 0.01 | <0.0001 | 0.023 | 0.274 |
C14:1 | 2.33 | 2.14 | 2.15 | 2.14 | 2.26 | 0.06 | 0.340 | 0.321 | 0.828 |
C16:0 | 18.82a | 18.45ab | 17.78b | 18.48 | 18.22 | 0.09 | <0.0001 | 0.105 | 0.906 |
C16:1 | 1.82a | 1.62a | 1.31b | 1.67 | 1.50 | 0.05 | <0.0001 | 0.026 | 0.750 |
C16:1t | 0.40ab | 0.42a | 0.37b | 0.40 | 0.40 | 0.01 | 0.017 | 0.648 | 0.987 |
C17:0 | 0.75 | 0.71 | 0.74 | 0.71 | 0.76 | 0.02 | 0.761 | 0.155 | 0.861 |
C17:1 | 0.77 | 0.68 | 0.69 | 0.67 | 0.75 | 0.02 | 0.076 | 0.026 | 0.872 |
C18:0 | 9.18 | 8.90 | 8.97 | 8.88 | 9.16 | 0.09 | 0.425 | 0.120 | 0.788 |
C18:1n9 | 27.77a | 27.28a | 25.30b | 27.31 | 26.25 | 0.25 | <0.0001 | 0.017 | 0.967 |
C18:1n7 | 2.33a(b) | 2.21(b) | 2.05c | 2.22 | 2.17 | 0.03 | <0.0001 | 0.296 | 0.595 |
C18:2 | 23.52c | 25.73b | 27.64a | 25.66 | 25.60 | 0.27 | <0.0001 | 0.864 | 0.586 |
C18:3n3 | 0.98 | 1.04 | 1.04 | 1.02 | 1.01 | 0.02 | 0.144 | 0.731 | 0.880 |
C18:3n6 | 0.15 | 0.15 | 0.16 | 0.16 | 0.15 | 0.003 | 0.775 | 0.060 | 0.513 |
C20:0 | 0.123 | 0.119 | 0.122 | 0.118 | 0.124 | 0.001 | 0.406 | 0.015 | 0.892 |
C20:1 | 0.32a | 0.32a | 0.29b | 0.30 | 0.31 | 0.004 | 0.002 | 0.421 | 0.472 |
C20:2 | 0.63b | 0.70ab | 0.77a | 0.66 | 0.74 | 0.02 | 0.003 | 0.015 | 0.982 |
C20:3 | 0.84a | 0.71b | 0.68b | 0.72 | 0.77 | 0.02 | 0.0007 | 0.134 | 0.345 |
C20:4 | 5.18 | 4.89 | 5.25 | 4.93 | 5.28 | 0.12 | 0.451 | 0.155 | 0.895 |
C22:4 | 1.48 | 1.47 | 1.58 | 1.45 | 1.57 | 0.03 | 0.306 | 0.066 | 0.476 |
C22:5 | 0.52 | 0.48 | 0.57 | 0.52 | 0.53 | 0.02 | 0.098 | 0.640 | 0.430 |
C22:6 | 0.48(a) | 0.40(b) | 0.42(ab) | 0.41 | 0.45 | 0.01 | 0.076 | 0.150 | 0.963 |
C24:1 | 0.15a | 0.13ab | 0.12b | 0.12 | 0.14 | 0.004 | 0.008 | 0.026 | 0.298 |
SFA is the sum of saturated fatty acids (C12:0 + C14:0 + C16:0 + C17:0 + C18:0 + C20:0)
MUFA is the sum of monounsaturated fatty acids (C14:1 + C16:1 + C16:1t + C17:1 + C18:1n9 + C18:1n7 + C20:1 + C24:1)
PUFA is the sum of polyunsaturated fatty acids (n3 + n6)
n3 = C18:3n3 + C22:5 + C22:6; C20:5 was not detected
n6 = C18:2 + C18:3n6 + C20:4 + C22:4 + C20:3 + C20:2
FAME are the fatty acid methyl esters
Unlike in our findings, where high DDGS diets affected a more tender breast meat (
Former trials showed that dietary PUFAs—in contrast to SFA or MUFA—decrease abdominal fat in broilers (Crespo and Esteve-Garcia, 2002). However, absolute increases in dietary PUFA content (+ 10.2% and + 27.7% in 16% DDGS and 24% DDGS compared to 8% DDGS, respectively, Table 3) in the present diets did not affect abdominal fat tissue. This may be caused by the concomitant absolute increase in dietary SFA content of diet in a comparable manner (+ 10.2% and + 26.0%, respectively) resulting in similar dietary PUFA-to-SFA ratios with a mean value of 1.94 ± 0.02. Furthermore, the energy intake as well as the N metabolism was similar between the treatments.
The composition of fatty acids in chicken tissues results from direct deposition of dietary fatty acids and endogenous fat synthesis (Cortinas et al. 2004). A general lipogenesis inhibition by dietary fat addition but a comparably higher endogenous synthesis is reported in broilers fed diets rich in PUFAs (Crespo and Esteve-Garcia, 2002). In our study, an increase in linoleic acid and total PUFA content because of increasing dietary DDGS supply up to 24% (and increased vegetable oil concentrations for isocaloric diets) in breast meat was observed. Schilling et al. (2010) and Heincinger et al. (2012) reported similar findings in broiler thigh and turkey breast, respectively. Furthermore, Corzo et al. (2009) also found increases in eicosadienoic acid (C20:2) with DDGS. However, unlike in the study of Schilling et al. (2010), we did not observe reductions in stearic acid in our breast meat samples. This discrepancy may result from differences in sampling site or origin of DDGS and dietary oil.
Although the PUFA-to-SFA ratio remained quite constant in feed despite increases in DDGS and fat content, only the PUFA family was incorporated in a higher manner in the intramuscular fat content. This is mirrored in a 14.6% increase in PUFA-to-SFA ratio in meat (from 8% DDGS to 24% DDGS,
In conclusion, the study could show that increasing DDGS contents up to 24% in broiler diets did not impair performance. A precondition, however, is a sufficient supply with nutrients to cover requirements. Supplementation of NSP-hydrolyzing enzymes improved ADG and FCR in grower and finisher phases. AMEN and DM digestibility as well as N retention were neither influenced by DDGS content nor enzyme supplementation. Hence, it seems that the improved FCR affected by enzyme supplementation is due to intermediate metabolism processes. The substitution of soybean meal and corn with DDGS and vegetable oil only had minor effects on the sensory quality of broiler breast meat, with increased tenderness in high DDGS diets (