Use of High Levels of Full-Fat Soybeans in Laying Hen Diets

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1 2005 Poultry Science Association, Inc. Use of High Levels of Full-Fat Soybeans in Laying Hen Diets N. Senkoylu,*,1 H. E. Samli,* H. Akyurek,* A. Agma,* and S. Yasar *Department of Animal Science, Trakya University, Tekirdag, Turkey; and Department of Animal Science, Suleyman Demirel University, Isparta, Turkey Primary Audience: Nutritionists, Commercial Egg Producers, Feed Ingredient Suppliers SUMMARY To examine the effects of various inclusion levels of full-fat soybeans (FFSB) on laying hen performance and eggshell quality during peak production, 288 Bovans White strain laying hens, 33 to 42 wk of age, were randomly assigned to 4 dietary treatments. The diets were prepared with the inclusion of 0, 10, 16, and 22% FFSB. Egg production was not significantly affected by any of the dietary treatments, whereas feed intake, egg weight, egg mass, and feed conversion ratio (FCR) were significantly affected. Overall, laying hens receiving the FFSB diets consumed significantly less feed than those on the control diet. Egg mass (gram per hen per day) tended to increase with increasing FFSB from 10 to 16 or 22% relative to the control diet. The FCR was significantly improved by all diets containing FFSB (1.79, 1.80, and 1.80 feed:egg ratio for the diets containing 10, 16, and 22% FFSB, respectively) compared with the control diet (1.87). However, none of the inclusion levels of FFSB in layer diets significantly affected shell weight, shell thickness, albumen height, or checked and cracked egg percentages. It was concluded that FFSB can be used in layer diets to an inclusion level of 22%. Key words: full-fat soybean, laying hen performance, egg quality 2005 J. Appl. Poult. Res. 14:32 37 DESCRIPTION OF PROBLEM Soybeans contain several antinutritional factors, such as trypsin inhibitors, lectins, saponins, and goitrogenic factors, which can have deleterious effects on the performance of chickens [1, 2]. Feeding of raw soybeans causes growth depression, poor feed efficiency, and pancreatic enlargement in young chickens and small eggs in laying hens [3]. Some of these effects have been shown to be due to the trypsin inhibitors, which reduce the digestibility of dietary proteins [4]. Various processing techniques involving heat treatment, such as dry and wet extrusion, roasting, and micronization, have long been used to deactivate the antinutritional compounds of this valuable protein source [5, 6]. However, the degree and duration of the heat treatment is of prime importance with respect to proper processing and the quality of the processed full-fat soybeans (FFSB). A great deal of research has accumulated on processing techniques for whole soybeans and their application in poultry diets. Both under- and overcooked whole soybeans cause growth depression and worsened feed use in poultry. The FFSB meal is often an attractive alternative ingredient and will be readily used in least cost formulations depending on its price relative to soybean meal, other protein sources, and feed fat [7]. The quality of soybeans has generally 1 To whom correspondence should be addressed: nsenkoylu@yahoo.com.

2 SENKOYLU ET AL.: FULL-FAT SOYBEANS IN LAYER DIETS 33 been controlled by feed-quality tests involving urease and protein dispersibility index [8] or protein solubility [9, 10]. The FFSB meal provides not only a protein source but also a source of high-quality oil, making them a valuable alternative to the use of vegetable oils in feed mills and in poultry farms that have no access or handling facilities available for liquid vegetable oil sources [11]. The FFSB meal or soybean oil provides a sufficient quantity of unsaturated fatty acids and especially linoleic acid [12], lysine, and vitamin E. Furthermore, FFSB can furnish about 30 to 50% of the bird s requirements for riboflavin, niacin, pantothenic acid, thiamine, folic acid, and choline in the lecithin of whole soybean essential for egg production [1, 13]. These nutritive factors and other benefits, including reduced dustiness and improved palatability of feeds, make FFSB desirable in layer feeds [7]. Relatively recent results [7, 14, 15] published with regard to inclusion of high levels of FFSB have demonstrated that the effects on laying hen performance and egg quality might differ significantly. Thus, it appears that incorporating FFSB into layer diets at rates higher than 10% and the extent to which it can be safely used in feed are topics that need to be further investigated in laying hens, especially during postpeak production. MATERIALS AND METHODS This experiment was carried out to determine the effects of various inclusion levels of FFSB in layer diets during peak production on laying hen performance and eggshell quality traits. Two hundred and eighty-eight 33-wk-old Bovans White strain [16] laying hens were provided from a local parent stock supplier (Bovans White) and randomly confined to commercial compact-type wire cages ( cm), 4 hens per cage, 528 cm 2 /hen. Battery cages were equipped with nipple drinkers, 1 nipple for 4 hens and trough feeders, to allocate 12 cm of feeder space per bird. The experiment was set up in a completely randomized design. Thus, 72 hens were randomly assigned to each of 4 treatments with 6 replicates per treatment. Each replicate represented 3 cages in which the hens were fed from the same feed trough. Laying hens were maintained in an experimental house TABLE 1. Chemical composition and calculated ME of full-fat soybean (as-fed basis) [17] Chemical composition g/kg Dry matter Crude protein Crude fiber 51.0 Ether extract Crude ash 55.0 Urease activity, mg of N/g min 0.28 ME n, kcal/kg DM 1 3,524 1 ME n (MJ/kg DM) = CP EE NFE, where EE = ether extract, and NFE = nitrogen-free extract [19]. with windows and received additional artificial light to provide 16.5L:7.5D daily. Four diets were prepared with the inclusion of 0, 10, 16, and 22% FFSB, respectively, and the main dietary ingredients, maize, soybean meal, sunflower meal, gluten meal, and fish meal supplied from the local feed market. The proximate composition of the FFSB was determined [17] and presented in Table 1. Experimental diets were formulated according to the Bovans White [16] recommendation to contain 17.6% CP and 2,816 kcal of ME/kg and to be isocaloric and isonitrogenous, as shown in Table 2. Diets were fed in mash form. Experimental diets were prepared at the feed mixing unit of the Department of Animal Science of Trakya University in Tekirdag, Turkey. The feed ingredients were ground in a hammer mill to pass a 3-mm sieve and mixed through a horizontal mixer (200-kg capacity). The experimental diets were fed to the laying pullets from 33 to 42 wk of age to determine the performance of laying hens with increasing levels of FFSB. Pullets received the diets and water ad libitum throughout the experiment, which lasted for 9 wk. Feeds were prepared biweekly and offered to the laying birds daily; feed intake was recorded weekly. Egg production and cracked eggs were determined daily; egg weight was measured weekly by weighing all the collected eggs on 1 d of the week from the experimental groups. Eggshell weight and thickness were determined weekly by randomly collecting 4 eggs from each replicate (24 eggs per treatment). After individually weighing the eggs, they were broken, the shells were washed and dried at room temperature for the determination of shell weight, and shell

3 34 JAPR: Research Report TABLE 2. The ingredients and chemical composition of experimental diets (as-fed basis) Full-fat soybean levels, % Ingredient, g/kg of diet Corn Full-fat soybean (38% CP) Soybean meal (48% CP) Sunflower meal (38% CP) Soybean oil 36.4 Maize gluten meal Fish meal (73% CP) Limestone Monocalcium phosphate Salt Vitamin + mineral mix DL-Methionine Phytase Total 1, , , ,000.0 Calculated nutrients, g/kg ME, kcal/kg 2,816 2,816 2,816 2,816 Crude protein Ether extract Linoleic acid Crude fiber Calcium Available phosphorus Sodium Lysine Methionine Methionine + cystine Threonine Tryptophan Provided per kilogram of diet: vitamin A, 8,000 IU (as retinyl acetate); vitamin D 3, 2,500 IU (as cholecalciferol); vitamin E, 30 mg (as α-tocopheryl acetate); vitamin K 3, 2.5 mg (as menadione sodium bisulfite); vitamin B 1 2 mg (thiamine); vitamin B 2, 5 mg (as riboflavin); vitamin B 6, 2 mg (as pridoxamine); vitamin B 12, 0.01 mg (as cyanocobalamin); niacin, 30 mg; calcium-d-pantothenate, 8 mg; folic acid, 0.5 mg; D-biotin, mg; choline chloride, 300 mg; vitamin C, 50 mg; MnO 2, 70 mg; FeSO 4 7H 2 O, 35 mg; ZnO, 70 mg; CuSO 4 5H 2 O, 8 mg; Ca(IO 3 ) 2. thickness was measured without membranes by taking the mean of 3 pieces (from the 2 ends and the middle) using a micrometer. Checked and cracked eggs were determined weekly on the same day by examining all the eggs collected from the cages. All eggs were candled to separate out the cracked and checked eggs. The sums of the checked and cracked eggs were calculated as the percentage of total collected eggs on the same day. Feed conversion ratio was calculated as grams of feed consumption per day per hen divided by grams of egg mass per day per hen [16]. The collected data were recorded on a weekly basis, and, afterwards, average data obtained by weeks (9 wk for each of the treatments) were statistically analyzed by ANOVA using the general linear model procedure in a Windowsbased statistical package program SAS [18]. The differences between the means of groups were separated by Duncan s multiple range test. The significance level used for the group comparisons was set at P < RESULTS AND DISCUSSION Increasing the inclusion level of FFSB from 0 to 22% in layer diets did not significantly (P > 0.05) affect hen-day egg production from 33 to 42 wk of age. The percentages of hen-day egg production were 96.7, 96.1, 97.2, and 97.3% for the control diet and diets containing 10, 16, and 22% FFSB, respectively (Table 3). In comparison with the control diet, the hens consumed significantly (P < 0.01) less feed when the diets

4 SENKOYLU ET AL.: FULL-FAT SOYBEANS IN LAYER DIETS 35 TABLE 3. Effects of full-fat soybeans (FFSB) levels on laying hen performance (33 to 42 wk of age) 1 Dietary Egg Feed level production, Feed Egg Egg conversion of FFB, hen-day intake weight mass ratio % (%) (g/hen per day) (g/egg) (g/hen per day) (g of feed/g of egg) a 61.8 ab 59.7 ab a c 61.1 b 58.7 b b bc 61.8 ab 60.1 a b ab 62.2 a 60.5 a b SEM P-level a c Means within the same column with different superscripts differ significantly (P < 0.05). 1 Means represent 6 replicates and 12 birds in each for 72 birds per treatment. contained 10 and 16% FFSB, whereas no significant (P > 0.05) difference was found in feed intake between the control diet and that with 22% FFSB. However, increasing FFSB in the diets from 10 to 22% significantly increased feed consumption. The pattern of feed intake indicated that the differences in feed consumption between the treatment groups were not likely to be due to the direct effects of FFSB inclusion levels. A look at the chemical composition of the experimental diets (Table 2) revealed that the lowest feed intake occurred with 10% FFSB diet, which has the lowest dietary fiber content (3.1%) and lowest fat content (5.12%) compared with the 16 and 22% FFSB diets (3.9 and 4.5%, respectively). The differences between the experimental diets in dietary fiber and fat content were seen to be due to the FFSB addition levels. We believe that these levels of dietary fiber could not possibly control the feed intakes of laying hens. However, FFSB contain an appreciable amount of ether extract (20.9%), a valuable source of fatty acids (Table 1). Thus, the addition of various levels of FFSB caused remarkable differences in the ether extract contents of experimental diets (5.12, 6.08, and 7.07% for 10, 16, and 22% FFSB addition levels, respectively). Moreover, the control diet, containing 6.86% ether extract, was formulated with a dietary fat source of soybean oil. Thus, the differences in ether extract contents of diets may clearly explain why there was no significant difference between the control and the 22% FFSB diet. There also were significant differences between the diets of 10 to 22% FFSB and the control diet in terms of feed intake. This suggests that feed intake could have been affected by the dietary ether extracts of experimental diets containing various levels of FFSB, possibly due to the fatty acid contents differing between the experimental diets. Egg weight (gram per egg) was not affected by the dietary treatments. Egg weight increased by 1 g as dietary FFSB was increased to 22%, as compared with 10% inclusion level. Although the difference in egg weight between the diets containing 10 and 22% FFSB was found to be significant, in general, in the present study an inconsistent pattern was observed in egg weight. However, a large significant increase in egg weight was previously reported with the diets of about 10% FFSB addition [7, 15]. Significant (P < 0.05) differences were observed in egg mass (gram per hen per day) between the dietary treatments (Table 3). The manner of the difference was found to be similar to the difference in egg weight. Furthermore, feed conversion ratio (FCR) was significantly improved by the diets containing FFSB as compared with the control diet (Table 3). Improved FCR with the diets containing FFSB could be due to the combination of less feed consumed and minor differences in egg mass and egg production compared with those consuming the control diet. Therefore, one could speculate that the reduced feed intake with the FFSB diets (which had been attributed to the effect of low ether extract) might have caused a reduction in egg performance. Instead, egg mass and FCR were significantly improved with the FFSB diets. Particularly, improved FCR was better with the low addition level (10%) than high addition levels of FFSB (16 and 22%). Unfortunately, we do not have any data regarding the

5 36 JAPR: Research Report TABLE 4. Effects of high levels of full-fat soybeans (FFSB) on egg quality (33 to 42 wk of age) 1 Dietary Checked level Shell Shell Shell Albumen and cracked of FFSB, weight weight thickness height Haugh eggs % (g) (%) (µ) (mm) units (%) SEM P-level Means represent 6 replicates and 4 eggs in each for 24 eggs per treatment. possible BW changes in the laying hens used in the present study to support these arguments. The same results were reported with 10% FFSB addition previously [7, 15]. None of the levels (0, 10, 16, and 22%) of dietary FFSB significantly (P > 0.05) affected either external or internal egg qualities (Table 4). Increasing the level of dietary FFSB from 0 to 22% did not significantly (P > 0.05) alter eggshell weight, eggshell thickness, or checked or cracked eggs percentages. Albumen height was not affected by the dietary treatments, suggesting that increased dietary FFSB had no adverse effect on albumen quality. Only 3 layers died during the experiment, and mortality could not, therefore, be subjected to statistical analysis. In contrast to our findings, Wyatt et al. [14] found no differences in egg production, feed intake, egg weight, and shell quality with the diets of FFSB (with TME n, 2,970 kcal/kg CP, 38.28%; ether extract, 18.78%) added at 0, 12.5, 17.5, and 22.5%, which were fed to 42- and 80- wk-old groups of laying hens for 16 wk with 128 hens per group (8 reps per diet per age) in which the laying hens breed was not indicated. Significant (P < 0.05) improvement in FCR (from 2.23 to 2.17) and an increase (from 2.37 to 3.83%) in the percentage of large eggs (66 to 70 g egg), albeit with no difference between the treatments in egg production (81.4 and 81.7%) or feed intake (98 and 97 g/hen), were reported by Swick [7] with diets containing 10% FFSB, processed by dry extrusion, compared with control diets containing soybean meal, based on total amino acid requirements. In this study [7], 2 feeding trials were conducted under conditions typical in Asia to assess the performance of FFSB in layer diets using ISA Brown and Golden Comet pullets. The trials were lasted for 30 and 20 wk, respectively. Swick [7] suggested formulating the diets on the basis of digestible amino acid requirements when FFSB was included since it was found to be more cost effective. The results of this study agree with the results obtained in our study with respect to improvement in FCR, no difference in egg production, tendency to increase in egg weight, and no consistent difference in feed intake. Experiments conducted by Koci et al. [15] studied the effects of FFSB inclusions, from 0 to 5 and 11%. They concluded that the diets containing 11% FFSB significantly (P < 0.05) increased egg production and egg weight with no negative impacts on egg quality, such as yolk and albumen percentages and Haugh units. The increased egg production, feed intake, and egg weight previously seen with diets containing 0, 5, and 11% FFSB [15] were not observed in our experiment. Koci et al. [15] reported a significant (P < 0.05) increase in egg production (274.9, 279.4, and eggs per layer, respectively) during a laying period of 324 d, with increasing FFSB inclusion. In their study, egg weights with respect to dietary treatments were found to be 60.3, 60.8, and 61.6 g, respectively, whereas feed intakes were 117.1, 121.0, and g, respectively. Feed conversion ratio did not differ between the treatments and were found to be 2.29, 2.31, and 2.29, respectively. Significant improvements in FCR and an increase in the percentage of large eggs (66 to 70 g) have been obtained with diets containing 10% FFSB relative to the control diets containing soybean meal [15]. Unlike the above results, the improved FCR in the present study is of great importance for the egg producers, and additionally, the high

6 SENKOYLU ET AL.: FULL-FAT SOYBEANS IN LAYER DIETS 37 addition levels of FFSB used in the present study was seen to act with no adverse affects on the performance and egg quality. In the present study, increasing the level of FFSB in the layer diets from 10 to 16% and then to 22% did not affect either egg production or egg quality. However, FCR was improved by the FFSB inclusions. The findings obtained in this study are in accordance with some previous studies [7, 15]. Therefore, the results of the present study show that layer diets can be supplemented with FFSB at levels higher than 10% and up to 22%. Increasing the level of FFSB in layer diets generally resulted in improved laying hen performance, whereas egg quality parameters were unaffected. CONCLUSIONS AND APPLICATIONS 1. Full-fat soybeans can be included at 22% in laying hen diets without any negative effect on laying hen performance. 2. Full-fat soybeans inclusion at high levels (22%) improved egg mass and FCR. REFERENCES AND NOTES 1. Balloun, S. L Soybean Meal in Poultry Nutrition. K. C. Lepley, ed. The Ovid Bell Press, Inc., Fulton, Missouri. 2. Liener, I. E Toxic Constituents of Plants Foodstuffs. Academic Press, New York. 3. Chubb, L. G Anti-nutritional factors in animal feedstuffs. Pages in Recent Advances in Animal Nutrition. W. Haresign, ed. Butterworld, London, England. 4. Zhang, Y., and C. M. Parsons Effect of extrusion and expelling on the nutritional quality of conventional and kunitz trypsin inhibitor-free soybeans. Poult. Sci. 72: Waldroup, P. W Whole soybeans for poultry feeds. Worlds Poult. Sci. J. 38: Parsons, C. M., K. Hashimoto, K. J. Wedekind, Y. Han, and D. H. Baker Effect of overprocessing on availability of amino acids and energy in soybean meal. Poult. Sci. 71: Swick, R. A Feeding full-fat soybean meal to layers in Asia. Pages in 2nd Int. Full Fat Soybean Conf. American Soybean Association, United Soybean Board, Budapest, Hungary. 8. AOAC Official Methods of Analysis. 17th rev. ed. Association of Official Analytical Chemists., Washington, DC. 9. Araba, M., and N. M. Dale Evaluation of protein solubility as an indicator of over processing soybean meal. Poult. Sci. 69: Parsons, C. M., K. Hashimoto, K. W. Wedekind, and D. H. Baker Soybean protein solubility in potassium hydroxide: An in vitro test of in vivo protein quality. J. Anim. Sci. 69: Speers, G. M High-energy soybeans for layers. Activity F02CX32936 June 22 July 4. American Soybean Association, Brussels, Belgium. 12. O Brien, R. D Pages 7 10 in Fats and Oils: Formulating and Processing for Applications. Technomic Publishing Co., Inc., Lancaster, Basel. 13. Ruiz, N., F. De Belalcaázar, and G. J. Díaz Quality control parameters for commercial full-fat soybeans processed by two different methods and fed to broilers. J. Appl. Poult. Res. 13: Wyatt, C. L., T. N. Goodman, and P. Tillman Effect of feeding processed full-fat soybeans (EN-R-G Flakes) to laying hens on production parameters, and egg cholesterol and fatty acid levels. Poult. Sci. 70(Suppl. 1):134. (Abstr.) 15. Koci, S., Z. Kociova, Z. Ceresnakova, O. Palanska, and T. Matrai The effect of full fat extruded soya on the performance and produce quality in layers and broilers. Zivocisna Vyroba 42: Bovans White Hendrix Poultry Breeders, A Nutreco Company. AC Boxmeer, The Netherlands. 17. Kalite Sistem Analiz Laboratory, Istanbul, Turkey. 18. SAS User s Guide. SAS Institute Inc., Cary, NC. 19. Janssen, W. M. M. A European Table of Energy Values for Poultry Feedstuffs. 3rd ed. Spelderholt Center for Poultry Research and Information Center Beekbergen, The Netherlends. Acknowledgments The authors thank Gures Tavukculuk A.S. for their kind support in providing the pullets and feed ingredients for this work.