Arch. Geflügelk. 2002, 66 (4), 151 – 157, ISSN 0003-9098. Verlag Eugen Ulmer GmbH & Co., Stuttgart Effect of exogenous endoxylanase on growth and feed conversion in turkeys fed on wheat-based diets Einfluss einer Supplementierung von Endoxylanase zu weizen-basierten Futtermischungen in der Putenmast Jeanette Boguhn1, R. Timmler1, J. Braun2 and M. Rodehutscord1 Manuskript eingegangen am 26. Oktober 2001, angenommen am 10. Januar 2002 Introduction Dietary soluble non-starch polysaccharides (NSP), particularly pentosans and beta-glucans, are well known to correlate in concentration with digesta viscosity in the small intestine of growing birds (Jeroch et al., 1995). Negative effects on ileal digestibility of nutrients and, consequently, on growth and feed conversion potentially result from this increase in viscosity. Ingredients which commonly show a high NSP concentration like wheat, rye and barley were, therefore, considered in diet formulation only to a very limited extent until enzyme preparations were developed to be supplemented to the diets. The soluble NSP concentration in grains, however, shows a high variation between batches. In 76 wheat samples collected in Sachsen-Anhalt in recent years, the average content of soluble NSP was 42 g/kg dry matter (DM) with a variation between 20 and 67 g/kg DM (Jeroch et al., 1999). In wheat, the soluble NSP concentration is negatively correlated with its content of apparently metabolisable energy (AME) (Annison, 1991; Choct and Annison, 1992). Exogenous NSP hydrolysing enzymes were repeatedly shown to be efficient in reducing digesta viscosity in broiler chicken when the enzyme was specific for the NSP dominating in the diet (Bedford, 2000; Choct, 2001; Dänicke et al., 2000). Dusel et al. (1998) and Choct et al. (1999) reported a reduced digesta viscosity as an effect of a xylanase supplementation in both jejunum and ileum of broilers that had been fed a wheat-based diet. Correspondingly, AME and digestibility tended to be increased with supplementary enzymes. In many cases, growth and feed conversion ratio (FCR) as well as litter quality were, therefore, positively affected by enzyme supplementation (Bedford, 2000). However, effects are not consistent. As mentioned, the supplemental enzyme must show the specific activity that is required to hydrolyse the NSP dominating in the feed. Furthermore, the NSP content must be sufficiently high to cause anti-nutritional effects. Male turkeys are commonly fed for 22 weeks under German market conditions. The amount of feed needed to achieve 1 kg of BW gain increases from 1.5 kg in week 3–5.5 kg in week 22 (NRC, 1994). Correspondingly, the concentration of nutrients in the diet, e.g. essential amino acids, can be continuously reduced with improving BW as 1 Institut für Ernährungswissenschaften, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany 2 BASF Forschungsstation Ernährung, Offenbach (Queich), Germany Archiv für Geflügelkunde 4/2002 reflected in current recommendations (NRC, 1994). A dietary allowance for crude protein between 19 and 14% (in wk 12 to 22) allows for an inclusion of wheat in the diet which is much higher than known from enzyme studies with commonly grown broiler chicken. Studies, however, on the inclusion of wheat and on the potential benefit of using exogenous xylanases in turkey diets are rare. Therefore, this study was conducted to investigate the effect of different enzyme preparations on growth and feed conversion in turkeys fed wheat-based diets over the entire fattening period. Material and methods Diets The feeding trial was conducted for 22 weeks. According to current practise in the German turkey industry, the fattening period was divided into 6 phases of 2 to 5 weeks (P1 to P6, see Table 1). Diet composition changed between phases in order to adjust to the respective recommendation for AME and nutrient concentration given by the breeding company and by the National Research Council (NRC, 1994). Table 2 shows the composition of the diets and the calculated concentrations of AME and major nutrients. A high inclusion of wheat (variety ‘Moldau’) was intended and the proportion of wheat increased from 45% in P1 to 81% in P6. The wheat was from the same batch all throughout the experiment. Solvent extracted soybean meal from dehulled seed, wheat and free amino acids were the amino acid sources. Animal fat with low melting point (beef tallow) was used as the lipid source to adjust ME concentration. Intended concentrations of crude nutrients were confirmed by analysis. Apart from a coccidiostat which was used in P1 to P4, no feed antibiotic or anti black head component was included. Four treatments were considered in the experiment with four diets prepared in each phase different in the supplemented enzyme preparation only (100 mg product/kg diet). The intended activities of endoxylanase (EXU/kg) were as follows: Treatment Treatment Treatment Treatment 1 2 3 4 EXU supplementation per kg diet Product no 825 5500 5600 no Natugrain1 Classic Natugrain1 Blend Natugrain1 Wheat 152 BOGUHN et al., Effect of exogenous endoxylanase on growth and feed conversion in turkeys fed on wheat-based diets Table 1: Duration of phases and time schedule of the experiment Einteilung der Phasen und Zeitplan des Versuchs Phase Start P1 P2 P3 P4 P5 P6 Age, weeks Duration, weeks Date of weighing, 2000 0 –– 7.3. 1–2 2 21.3. 3–5 3 11.4. 6–9 4 9.5. 10–13 4 6.6. 14–17 4 4.7. 18–22 5 8.8. Table 2: Composition of diets and calculated nutrient concentration Zusammensetzung der Futtermischungen und kalkulierte Nährstoffgehalte Phase P1 P2 P3 P4 P5 P6 Composition (%): Wheat Soybean meal, deh. seed Beef tallow Fish meal, 70% CP L-lysine HCl DL-methionine L-threonine Premix1 MCP Limestone NaCl Cholinechloride 45.31 40.00 6.00 2.50 0.48 0.31 0.09 1.00 2.23 1.62 0.34 0.12 50.98 35.00 6.00 2.00 0.39 0.29 0.12 1.00 2.35 1.45 0.30 0.12 60.72 26.00 6.50 1.00 0.58 0.28 0.13 1.00 1.72 1.70 0.25 0.12 68.02 18.50 6.50 1.00 0.55 0.25 0.19 1.00 1.82 1.80 0.25 0.12 74.10 12.50 7.00 1.00 0.41 0.21 0.11 1.00 1.65 1.65 0.25 0.12 80.95 6.00 7.00 1.00 0.40 0.17 0.08 1.00 1.56 1.47 0.25 0.12 Calculated: AMEN, MJ/kg Crude protein,% Lysine,% Met þ Cys,% Threonine,% Tryptophan,% Arginine,% Isoleucine,% Leucine,% Valine,% Histidine,% Phenylalanine,% Calcium,% Phosphorus (total),% Magnesium,% Sodium,% 11.6 27.2 1.80 1.16 1.10 0.32 1.81 1.17 2.06 1.25 0.73 1.25 1.41 1.01 0.17 0.18 11.8 25.3 1.60 1.08 1.02 0.29 1.65 1.07 1.90 1.15 0.67 1.14 1.31 1.00 0.16 0.15 12.2 21.2 1.45 1.01 0.86 0.24 1.32 0.87 1.57 0.95 0.56 0.90 1.20 0.80 0.15 0.12 12.4 18.8 1.25 0.90 0.79 0.21 1.12 0.75 1.37 0.83 0.49 0.76 1.20 0.80 0.13 0.12 12.8 17.0 1.00 0.81 0.63 0.18 0.94 0.65 1.20 0.73 0.43 0.63 1.10 0.75 0.12 0.12 13.0 15.0 0.85 0.72 0.52 0.16 0.77 0.55 1.04 0.63 0.37 0.51 1.00 0.70 0.12 0.12 1 composition (per kg, premix for P1 to P4, premix for P5 and P6 in parenthesis): Vit. A 1200000 (800000) IU; Vit. D3 400000 (300000) IU; Vit. E 4000 (4000) mg; Vit. K 240 (200) mg; Vit. B1 210 (200) mg; Vit. B2 720 (600) mg; Vit. B6 400 (300) mg; Vit. B12 2.3 (2.0) mg; Niacin 6600 (6000) mg; Ca-D-Pantothenate 1350 (1100) mg; Folic acid 150 (100) mg; Biotine 17.5 (12.6) mg; Ca 308 (335) g; Iron 5000 (5000) mg; Copper 1000 (1000) mg; Zinc 6000 (6000) mg; Manganese 8000 (8000) mg; Cobalt 25 (25) mg; Iodine 100 (100) mg; Selenium 35 (35) mg; Butylhydroxytoluol 7500 (5000) mg; Monensin-sodium (C36H61O11Na, as coccidiostat) 10000 mg (none in P5 and P6) In two of the products, beta-glucanase was contained as well. Calculated supplementation of beta-glucanase units was (in BGU/kg): treatment 1: 0, treatment 2: 600, treatment 3: 120, and treatment 4: 0. Table 3: Analysed activity of endoxylanase (EXU/kg) in the diets Analysierte Aktivität der Endoxylanase in den Futtermischungen (EXU/kg) Endoxylanase supplementation (EXU/kg) 0 P1 P2 P3 P4 P5 P6 1 <200 <200 <200 <200 <200 <200 1 Lower limit of detection 825 5500 5600 940 795 775 955 1040 993 4665 4250 4820 5115 4595 4330 5515 4285 5650 5470 5485 5329 Enzyme preparations were supplied by BASF AG, Ludwigshafen. All diets were mixed approximately 2 weeks before onset of the respective phase and pelleted through a 3-mm die. For week 1, pellets were crumbled. Enzyme activities determined in the pelleted diets basically agreed with intended activities (Table 3). Animals and housing The experiment was conducted in the Experimental Centre for Animal Sciences of the University in Merbitz. Threehundred and sixty one-day old male B.U.T. Big 6 hybrids (Moorgut Kartzfehn, Bösel) were allocated to pens (2 2 m) of ten birds each according to body weight. As space was limited, the number of birds per pen was reduced to 8 at the beginning of P5, with those individuals being eliminated which were nearest to the respective pen average. Pens were set up in 4 rows within a separate, artificially illuminated animal house. Temperature was 36 C on days 1 and 2 and was reduced from day 3 onArchiv für Geflügelkunde 4/2002 BOGUHN et al., Effect of exogenous endoxylanase on growth and feed conversion in turkeys fed on wheat-based diets 153 wards in steps of 0.5 C per day until 16 C were reached. During summer, room temperature was largely affected by outdoor temperatures because cooling of the animal house was not possible. Wood shavings and chaffed straw were used as basal bedding. When required, pens were supplied with additional wood shavings in similar amount for each pen. Nine pens were allocated to each of the 4 dietary treatments in that way that an equal distribution of all treatments over the animal house was given. Birds underwent routine vaccination against Newcastle Disease in weeks 2, 7 and 16. Vaccination against infectious bronchitis was in weeks 4 and 10. Diets contained a coccidiostat during phases 1 to 4. No other medical treatment was necessary. Feed was offered in automatic feeders ad libitum, continuously. Feeders were re-filled with pre-weighed amounts when required. During the first 5 days of P1, feed was additionally offered in flat plastic bowls. Birds had permanent access to fresh and untreated drinking water. Analyses Data Results On day 1 of the experiment and at the end of each phase, animals as well as the amount of feed remaining in the feeder were determined. Average body weight (BW) gain of birds was determined as the average BW within each pen at the end minus the average BW within this pen pen at the beginning of each period. Feed consumption per bird was calculated as the total amount of feed consumed by one pen per phase divided by the number of birds per pen. In case of any elimination of individuals between regular weighing dates, the amount of feed needed until this day was recorded and the amount of feed used subsequently was divided by the reduced number of animals. From P3 onwards, the appearance of excreta and bedding was visually evaluated and ranked once weekly before the addition of new wood shavings according to the following categories: wet (1), semi-wet (2) and dry (3). Each pen was given one of these three numbers at each date. For data evaluation, the cumulative number for each pen at the end of the experiment was divided by the number of observations. Thus, one value between 1 and 3 was used per pen for statistical analysis. No separate evaluation was made for individual phases as these were rather rough criteria. A considerable number of birds had to be removed during the experiment due to broken wings and leg deformities or crop development. These removals were similar in number in all treatments. During P5 and P6, the number of birds was reduced from 72 to 60, 63, 56 and 56 in treatments 1, 2, 3 and 4. Birds increased, on average, their BW from 60 g to 20.35 kg during the 22-week period (Table 4). No significant effect of treatment on BW was detectable at any time. At the end of the experiment, BW of birds fed endoxylanase at 625, 5500 and 5600 EXU/kg exceeded the BW of birds fed no enzyme by 0.4, 3.0, and 1.0%, respectively. Correspondingly, average daily BW gain over the entire experimental period was 0.6, 3.4, and 0.9% higher in birds which received endoxylanase at 625, 5500 and 5600 EXU/kg, respectively, than it was in birds fed the unsupplemented diet (Table 5). No significant treatment effect was detectable in any of the phases or over the entire experiment. Average daily BW gain increased from 22.1 g/ bird in P1 to a maximum of 169.8 g/bird in P5, and was, on average, 145.8 g/bird during P6. Average daily feed consumption increased from 30 g/ bird in P1 to 550 g/bird in P6 (Table 6). During P6, feed consumption by birds which received the highest endoxy- Diets were analysed for Weende crude nutrients, starch and sugar according to the official VDLUFA methods (Naumann and Bassler, 1976). AMEN was estimated based on chemical analysis using the generally accepted equation for poultry mixed diets (WPSA, 1984): AMEN (MJ/kg) ¼ [15.51 crude protein (g/kg) þ 34.31 crude fat (g/kg) þ 16.69 starch (g/kg) þ 13.01 sucrose (g/kg)] 103 Endoxylanase activity was determined in each diet for each phase according to the procedure described by Engelen et al. (1996). Data were subjected to ANOVA procedures using the software package SPSS for windows 9.0. Significant differences between treatments were detected by the Tukey-HSD test. Table 4: Body weight (g) of turkeys at the beginning of the experiment and at the end of each phase (mean SEM, n ¼ 9) Lebendmasse der Puten (g) zu Beginn des Versuches sowie am Ende jeder Phase Endoxylanase supplementation (EXU/kg) at start end of P1 end of P2 end of P3 end of P4 end of P5 end of P6 P 0 825 5500 5600 (ANOVA) 59 0.6 370 4.3 1795 17.9 5731 66.6 10280 96.0 14914 205.8 20125 305.1 60 0.4 371 6.9 1785 15.5 5622 65.3 10268 160.5 15111 269.6 20206 246.0 59 0.6 369 3.9 1771 18.1 5602 61.8 10343 70.3 15482 188.2 20730 225.3 60 0.7 371 4.1 1801 13.1 5764 46.3 10743 194.7 15326 190.7 20326 318.8 0.92 Archiv für Geflügelkunde 4/2002 0.98 0.60 0.18 0.07 0.29 0.43 154 BOGUHN et al., Effect of exogenous endoxylanase on growth and feed conversion in turkeys fed on wheat-based diets Table 5: Average daily BW gain (g) of turkeys in each phase and during the entire experiment (mean SEM, n ¼ 9) Täglicher Zuwachs an Lebendmasse (g) in den einzelnen Phasen und während des Gesamtversuches Endoxylanase supplementation (EXU/kg) P1 P2 P3 P4 P5 P6 total P 0 825 5500 5600 (ANOVA) 22.0 0.38 67.8 0.91 138.4 2.57 162.2 2.48 164.5 9.82 146.8 10.44 22.3 0.48 67.3 0.53 136.7 1.93 164.3 4.57 174.6 10.23 143.7 10.23 21.8 0.41 66.1 0.80 135.5 1.84 169.6 2.26 178.9 5.98 151.6 4.85 22.2 0.31 68.1 0.76 141.5 1.52 177.9 8.14 161.1 6.53 141.1 5.00 0.83 129.5 1.89 130.4 1.60 133.9 1.48 130.7 1.94 0.27 0.19 0.14 0.41 0.82 0.33 Table 6: Average feed consumption (g/d) of turkeys in each phase and during the entire experiment (mean SEM, n ¼ 9) Futteraufnahme (g/Tag) in den einzelnen Phasen und während des Gesamtversuches Endoxylanase supplementation (EXU/kg) P1 P2 P3 P4 P5 P6 Total P 0 825 5500 5600 (ANOVA) 29.8 0.25 80.9 1.05 239.6 3.69 410.6 6.13 497.1 10.70 564.5a 10.94 29.5 0.33 79.7 1.13 235.7 4.11 414.1 7.18 509.3 10.73 563.5a 10.78 29.5 0.47 78.2 0.98 237.8 4.71 409.4 6.10 503.5 12.08 555.0a 13.50 29.5 0.23 79.5 1.13 238.7 3.60 413.9 7.01 500.3 9.08 518.4b 11.88 0.92 350.6 4.18 352.4 4.66 348.7 5.25 341.0 4.46 0.39 0.92 0.95 0.87 0.03 0.34 a, b : means not sharing a common superscript are significantly different according to Tukey-HSD test Table 7: Feed conversion ratio (feed/BW gain) in each phase and during the entire experiment (mean SEM, n ¼ 9) Futterverwertung (Futter/Zuwachs) in den einzelnen Phasen und während des Gesamtversuches Endoxylanase supplementation (EXU/kg) P1 P2 P3 P4 P5 P6 total P 0 825 5500 5600 (ANOVA) 1.34 0.017 1.19 0.011 1.71 0.016 2.53 0.032 3.10 0.172 4.06 0.396 1.33 0.021 1.18 0.009 1.72 0.019 2.54 0.104 2.98 0.141 4.15 0.428 1.34 0.016 1.17 0.010 1.74 0.025 2.42 0.045 2.84 0.100 3.68 0.133 1.33 0.025 1.17 0.011 1.69 0.026 2.36 0.104 3.15 0.159 3.69 0.087 0.96 2.71a 0.048 2.70a 0.023 2.61b 0.036 2.61b 0.024 0.31 0.42 0.31 0.44 0.59 0.05 a, b : means not sharing a common superscript are significantly different according to Tukey-HSD test Archiv für Geflügelkunde 4/2002 BOGUHN et al., Effect of exogenous endoxylanase on growth and feed conversion in turkeys fed on wheat-based diets 155 Table 8: Ranking of the appearance of excreta and bedding1 (mean SEM, n ¼ 9) Beurteilung der Beschaffenheit von Exkrementen und Einstreu Endoxylanase supplementation (EXU/kg) Excreta Bedding 1 P 0 825 5500 5600 (ANOVA) 1.90 0.071 1.65b 0.146 1.91 0.061 1.70b 0.107 2.06 0.048 2.13ab 0.158 2.03 0.081 2.30a 0.201 0.24 0.01 appearance of excreta and bedding was ranked according to the following categories: wet (1), semi-wet (2) and dry (3). The higher the number the drier the bedding was : means not sharing a common superscript are significantly different according to Tukey-HSD test a, b lanase level was significantly lower (P ¼ 0.03) than by birds receiving no enzyme. Apart from this, no significant treatment effect was detectable. On overall average, birds receiving endoxylanase at 5500 and 5600 EXU/kg consumed 0.5% and 2.7%, respectively, less feed than birds receiving no enzyme. From the total amount of feed consumed by turkeys, the average distribution to the 6 phases was: P1 0.8%, P2 3.1%, P3 12.4%, P4 21.5%, P5 26.3%, and P6 35.9% with negligible differences between treatments. The feed/gain ratio increased from approximately 1.3 in P1 to 3.9 in P6, with an overall average of 2.66 (Table 7). This is slightly better than the current average obtained in hybrids with this genotype (2.7). The fact, that the feed/ gain ratio was slightly worse in P1 than in P2 must not be paid too much attention because feed wastage is difficult to handle during the first week when birds are not yet adapted to the automatic feeders. Less than 1% of total feed was consumed during P1. While there was hardly any difference between treatments in phases 1, 2, and 3, the endoxylanase supplementation of 5500 and 5600 EXU/kg tended to improve feed/gain ratio from P4 onwards. Although this effect was statistically not significant due to the high variation in the control treatment, the differences accounted for 9% in P6. During the entire experiment, birds which received endoxylanase at 5500 and 5600 EXU/kg needed 3.7% less feed per unit of gain than the control birds did, with a significant treatment effect (P ¼ 0.05). The bedding of the pens appeared significantly drier (P < 0.05) when birds received 5600 EXU/kg as compared to the control pens (Table 8). A similar trend was observed for excreta as well. composition and on the enzyme were not given in this abstract. In their literature survey, Jeroch et al. (1995) conclude that the effectiveness of enzyme supplementation might change in broilers with increasing age due to the adjustment of the gut microflora. Hence, broiler growth studies on enzyme efficiency had to comprise the entire growth period in order to get meaningful and generally applicable results. This conclusion must be emphasised in face of the present results. Although no significant treatment effect could be determined for any of the phases, it becomes clear from table 7 and figure 1 that the numerical difference between the control treatment and the treatments with the high inclusion of endoxylanase become greater with progress in the experiment beyond P3. This is likewise an effect of increasing inclusion of wheat and the corresponding increase in NSP rather than an effect of age of the animal. For practical application this is important in so far that only approximately 16% of total feed were used in periods 1 to 3. The severe reduction in protein in later phases of turkey feeding and the consequences for the inclusion of wheat made the endoxylanase more efficient than in the early phases. In so far this is not in contrast to the hypothesis, that enzymes are more efficient in younger birds than in older ones due to the adjustment in the gut microflora. Over the entire experimental period, the enzyme supplementation allowed to reach the final BW with 2 kg less feed. relative 100 90 Discussion It has been extensively reviewed (Bedford, 2000; Choct, 2001; Jeroch et al., 1995) that a high inclusion of wheat in poultry diets favours the risk for increased digesta viscosity and subsequent anti-nutritional effects and that this risk can be reduced by supplementation of a suitable exogenous enzyme. The results indicate that this happened in the present study as well although we were unable to measure digesta viscosity or ileal digestibility. At least this theory is supported by the significant improvement in feed conversion and the appearance of the bedding with supplementary endoxylanase. Dose-response-relationships cannot be concluded from the present study. A supplementary level of 825 EXU/ kg, however, was not sufficient to achieve any effect. Comparable studies with heavy turkeys fed on wheatbased diets are hardly available in the peer-reviewed literature. A significant improvement in BW gain and FCR caused by a supplementation of an enzyme complex derived from Trichoderma viride to a wheat-based diet was reported by Völker and Tüller (1993), but details on diet Archiv für Geflügelkunde 4/2002 80 70 50 0 P1 P2 P3 P4 Phase P5 P6 Fig 1. Feed conversion (g feed/g BW gain) in turkeys receiving a wheat-based diet supplemented with endoxylanase (average of treatments 3 and 4, relative to the unsupplemented control diet ¼ 100). The inclusion of wheat in the diet increased gradually from 45% in P1 to 81% in P6. Futterverwertung (g Futter/kg LM-Zuwachs) bei Puten, die eine weizen-basierte Futtermischung mit Endoxylanase erhalten haben (Mittelwert der Behandlungen 3 und 4, relativ zur Kontrolle ¼ 100). Der Mischungsanteil des Weizens im Futter stieg schrittweise von 45% in P1 auf 81% in P6 an. 156 BOGUHN et al., Effect of exogenous endoxylanase on growth and feed conversion in turkeys fed on wheat-based diets Beef tallow was used as the fat source in this study. Dänicke et al. (2000) fed rye-based diets with incremental level of beef tallow to the expense of soybean oil (100 g fat/kg in total) to broiler chicken and found, that the effect of a xylanase supplementation on metabolisability of energy and on FCR was greater in diets >60 g tallow/kg than in those with tallow below this level. This interaction between supplementary enzyme and fat source might exist also in turkeys without inclusion of rye. At this stage it can only be speculated whether the results of this study would have been similar with a different type of diet. Reducing the incidence of wet litter is one of the reasons identified for the use of exogenous enzymes (Bedford, 2000) and a positive effect of endoxylanase on the appearance of the bedding was found in this study as well. Enzymatic hydrolysis of uric acid and release of ammonia from the litter is well known to depend on the water content of the litter. No measurements on dry matter content of the bedding or on ammonia emission from the pens were possible in this study. It appears worth, however, to study whether positive effects on the gaseous N emissions from intensive turkey production could be achieved by supplementation of NSP-hydrolysing enzymes. von Weizen gefüttert. In 6 aufeinander folgenden Phasen wurde der Weizenanteil von 45% zu Beginn bis auf 81% am Ende des Versuchs gesteigert. Der Versuch umfasste 4 Behandlungen, die sich nur in der Supplementierung von Endoxylanase (EXU/kg) unterschieden: 0 (Kontrolle), 825 (Produkt Natugrain1 Classic), 5500 (Produkt Natugrain1 Blend) und 5600 (Produkt Natugrain1 Wheat). Jede Behandlung umfasste 9 Abteile mit je 10 eingestallten Eintagsküken. Die Lebendmasse und der Futterverbrauch wurden am Ende von jeder der 6 Perioden bestimmt. Die Einstreu wurde einmal wöchentlich visuell bonitiert und in eine der drei folgenden Kategorien eingeteilt: nass, feucht und trocken. Während des Versuches nahmen die Tiere von durchschnittlich 60 g zu Beginn auf 20,35 kg Lebendmasse am Ende zu. Ein signifikanter Einfluss des Zusatzes von Endoxylanase auf den Zuwachs war nicht gegeben. Der Futteraufwand je kg Zuwachs war über den gesamten Versuchszeitraum betrachtet in den beiden Behandlungen mit der hohen Enzymdosierung signifikant geringer als in der Kontrolle (2,61 zu 2,71 kg). Innerhalb der einzelnen Phasen war der Futteraufwand je kg Zuwachs wegen der höheren Streuung nicht signifikant von dem Enzymzusatz beeinflusst. Allerdings wurde der Enzymeffekt mit zunehmendem Weizenanteil im Futter immer deutlicher. In der Behandlung mit der höchsten Dosierung von Endoxylanase war die Einstreu signifikant trockener als in der Kontrolle. Es wird geschlussfolgert, dass ein Zusatz von Endoxylanase die Futterverwertung und die Einstreubeschaffenheit in der Putenfütterung auf der Basis von Weizen positiv beeinflussen kann, besonders in der zweiten Hälfte der Mastperiode. Summary In a 156-day feeding trial, male B.U.T. Big 6 turkeys were fed on wheat based diets with inclusion of wheat gradually increasing in 6 phases from 45% at the beginning to 81% at the end. Four treatments were involved, differing in the supplementation of exogenous endoxylanase (EXU/kg): 0 (control), 825 (from Natugrain1 Classic), 5,500 (from Natugrain1 Blend), and 5,600 (from Natugrain1 Wheat). Each treatment comprised 9 pens with an initial number of 10 turkeys each. Body weight and feed intake were determined at the end of each of the six phases. The bedding in the pens was visually evaluated once a week and ranked according to the three categories wet, semi-wet, and dry. The turkeys increased, on average, their BW from 60 g to 20.35 kg during the entire experiment without any significant treatment effect. The feed conversion ratio was significantly improved when either 5,500 or 5,600 EXU/kg were supplemented as compared to the unsupplemented control diet (2.61 vs. 2.71 kg feed/kg BW gain). No significant treatment effect on feed conversion was detected in any of the individual phases due to the high variation. However, there was a trend towards a more pronounced treatment effect with increasing inclusion of wheat in the diet. At the highest levels of enzyme supplementation, the bedding appeared significantly drier as compared to the unsupplemented control. It is concluded, that exogenous endoxylanase at 5,500 EXU/kg is effective in improving feed conversion and litter quality when supplemented to wheat-based turkey diets, particularly during the second half of the growth period. Keywords Turkey, wheat, endoxylanase, enzyme, growth, feed conversion Zusammenfassung Einfluss einer Supplementierung von Endoxylanase zu weizen-basierten Futtermischungen in der Putenmast Männliche Puten der Herkunft B.U.T. Big 6 wurden in einem Fütterungsversuch über 156 Tage mit Futtermischungen auf der Basis Stichworte Pute, Weizen, Endoxylanase, Enzym, Wachstum, Futterverwertung References Annison, G., 1991: Relationship between the levels of soluble nonstarch polysaccharides and the apparent metabolizable energy of wheats assayed in broiler chickens. J. Agric. and Food Chem. 39, 1252–1256. Bedford, M. R., 2000: Exogenous enzymes in monogastric nutrition-their current value and future benefits. Anim. Feed Sci. Technol. 86, 1–13. Choct, M., 2001: Enzyme supplementation of poultry diets based on viscous cereals. In: Bedford, M. R. and Partridge, G. G.: Enzymes in Farm Animal Nutrition. CABI Publishing, Wallingford, 145–160. Choct, M. and Annison, G., 1992: Anti-nutritive effect of wheat pentosans in broiler chickens: Roles of viscosity and gut microflora. Brit. Poultry Sci. 33, 821–834. Dänicke, S., Jeroch, H., Böttcher, W. and Simon, O., 2000: Interactions between dietary fat type and enzyme supplementation in broiler diets with high pentosan contents: effects on praecaecal and total tract digestibility of fatty acids, metabolizability of gross energy, digesta viscosity and weights of small intestine. Anim. Feed Sci. Technol. 84, 279–294. Dusel, G., Kluge, H., Jeroch, H. and Simon, O., 1998: Xylanase supplementation of wheat-based rations for broilers: influence of wheat characteristics. J. Appl. Poultry Res. 7, 119–131. Engelen, A. J., van der Heeft, F. C. and Randsdorp, P. H. G., 1996: Viscometric determination of b-glucanase and endoxylanase activity in feed. J. AOAC Int. 79, 1019–1025. Jeroch, H., Dänicke, S. and Brufau, J., 1995: The influence of enzyme preparations on the nutritional value of cereals for poultry. A review. J. Anim. Feed Sci. 4, 263–285. Jeroch, H., Kluge, H., Simon, O. and von Lengerken, J., 1999: Inhaltsstoffe und Futterwertdaten von Getreide und Körnererbsen. Institut für Ernährungswissenschaften, Universität HalleWittenberg, table collection. Naumann, C. and Bassler, R., 1976: VDLUFA-Methodenbuch, Vol. III.: Die chemische Untersuchung von Futtermitteln. Neumann-Neudamm, Melsungen (loose leaflet collection, with supplements). Archiv für Geflügelkunde 4/2002 BOGUHN et al., Effect of exogenous endoxylanase on growth and feed conversion in turkeys fed on wheat-based diets NRC, 1994: The nutrient requirement of poultry. National Academic Press, Washington D.C. Völker, L. and Tüller, R., 1993: Effect of Roxazyme G supplementation to wheat- and wheat/barley-based diets on the performance of growing turkeys. In: C. Wenk and M. Boessinger: Enzymes in Animal Nutrition, Proceedings of the 1st symposium, ETH Zürich, p. 141–143. 157 WPSA, 1984: The prediction of apparent metabolizable energy values for poultry in compound feeds. World’s Poult. Sci. J. 40, 181–182. Correspondence: Prof. Dr. M. Rodehutscord, Institut für Ernährungswissenschaften, Martin-Luther-Universität Halle-Wittenberg, Emil-Abderhalden-Str. 26, 06108 Halle (Saale), Germany. E-mail: [email protected] Buchbesprechung Enten und Gänse Heinz Pingel, Enten und Gänse, Verlag Eugen Ulmer, Stuttgart, Neuerscheinung 2000, 27 Farb- und 3 s/w-Abbildungen, 45 Zeichnungen, 61 Tabellen, 71 Literaturangaben, 182 Seiten, ISBN 3-8001-3156-0, Preis 1 24,90 Mit diesem informativen Fachbuch, vorgelegt von einem in der Forschung und Praxis der Wassergeflügelzucht international anerkannten Fachmann, wird eine Lücke auf dem Buchmarkt geschlossen. Die Zucht und Mast von Enten und Gänsen, bisweilen noch als randständiger Haupt- oder Nebenerwerb betrachtet, haben in Europa an Bedeutung gewonnen, ganz zu schweigen von ihrer beachtlichen Stellung in der Geflügelproduktion asiatischer Länder und einiger anderer Gebiete. Das Buch, reichlich mit Abbildungen und Tabellen ausgestattet, spiegelt den neuesten Erkenntnisstand wider. (Die zwei Bilder von Gänsen auf dem Umschlag erwecken aber den Eindruck, es handele sich um eine nur dieser Geflügelart gewidmete Ausgabe.) Im Mittelpunkt stehen die Abschnitte über Zucht und Reproduktion (treffender wäre: Züchtung und Reproduktion), Haltung sowie Fütterung. Eine ausführliche Einführung in die biologischen Grundlagen erweist sich für das Verständnis der Zusammenhänge als sehr nützlich. Der Abschnitt über die Rassen sollte um einige Aspekte erweitert werden (z. B. genetische Ressourcen, die Situation in anderen europäischen Ländern). Der berblick über die Produkte der Enten- und Gänsehaltung offenbart die Möglichkeiten ihrer gegenwärtigen und künftigen Verwertung. Hinweise zur Gesunderhaltung der Bestände (Krankheiten, Hygiene) ergänzen die bersicht, doch fehlen im Quellenverzeichnis Verweise auf vertiefende Literatur zu diesem Fragenkomplex. Die Lektüre des Buches kann selbst für Kenner des Wassergeflügels als eine Bereicherung des Wissens gelten, zumal zu Archiv für Geflügelkunde 4/2002 diesem Teilgebiet der Geflügelwirtschaft nur ein spärliches Schriftenangebot besteht. Einige wenige Hinweise für eine 2. Auflage: Mulardenten werden unter den Rassen, neben Haus- und Moschusenten aufgeführt. Sie sollten deutlicher als Bastarde (Gattungsbastarde) ausgewiesen sein. Der Autor nutzt den Begriff Moschusenten, der auch international (Muscovy Duck) üblich ist. In der Rassegeflügelzucht hat man sich auf die Bezeichnung Warzenenten geeinigt (weitere Namen wie Türken-, Bisam- oder Flugenten, sind lokal verbreitet). Man hätte allgemein den Namen Moschusente beibehalten sollen, denn Synonyme stiften meist Verwirrung, nutzt man doch im Handel nun die Bezeichnung Barbarieente. Der Autor erwähnt die Salztoleranz der Enten. Hierzu wäre ein Hinweis auf die Nasendrüsen sowie die Nebennieren wünschenswert, die bei der hormonalen Regulation der Salzausscheidung eine herausragende Rolle spielen. Die Angaben zum Wachstum der Pekingenten (Abb. 20) beruhen auf der Anwendung mathematischer Wachstumsfunktionen, verwundern aber ein wenig, da die höchsten Zunahmen schon in einem sehr frühen Alter verzeichnet wurden, wesentlich zeitiger als bei anderen Haustieren. Bedeutsam für ein solches Buch sind Darlegungen zum Tierschutz. Hier vermisst man Angaben über das Verbot der Zwangsfütterung in Deutschland (Stopfen und Nudeln von Gänsen oder Mulardenten, die Erzeugung von Gänseleberpasteten. Auf S. 151 wird erwähnt, dass dies in Frankreich noch üblich ist). Die Angaben über Enteneier sollten um den Hinweis auf die Enteneierverordnung (BGbl. I, 1954) ergänzt werden. Dieses Fachbuch empfiehlt sich durch übersichtliche Darstellung der Zusammenhänge, ausführliche Wiedergabe neuer Erkenntnisse und umfassender praktischer Erfahrungen. Jeder, der sich im Haupt- oder Nebenerwerb mit Wassergeflügel befasst, sollte dieses Werk ausgiebig zu Rate ziehen. W. Rudolph
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