Requirement of the Laying Hen for Apparent Fecal Digestible Lysine

Transcription

1 Requirement of the Laying Hen for Apparent Fecal Digestible Lysine J. B. SCHUTTE1 and W. SMINK TNO-Institute of Animal Nutrition and Physiology (ILOB), P.O. Box 15, 6700 AA Wageningen, The Netherlands ABSTRACT A study was conducted to determine the requirement for lysine of a White Leghorn strain of hens with a body weight of approximately 1,600 g. Before starting the experiment, apparent fecal digestibility of amino acids of the basal diet was determined in an in vivo digestibility trial with six individually housed hens. The basal diet used was based on corn and soybean meal and contained 0.65% total and 0.49% apparent fecal digestible lysine. To the basal diet, seven graded dose levels (0.04, 0.08, 0.12, 0.16, 0.20, 0.24, and 0.28%) of lysine as L-Lysine HCl were added. The experimental diets were fed for 12 wk, covering the early stage of laying from 24 to 36 wk of age. Each experimental diet was fed to 60 individually caged housed birds. The dietary lysine requirement was found to be higher for maximizing efficiency of feed utilization than for obtaining maximum egg mass yield. Based on the feed conversion efficiency and at an egg mass yield of 57 g/hen-d, the requirement for total lysine was estimated to be about 900 mg/hen-d. From the results of the digestibility trial, it was calculated that the estimated requirement for total lysine was equivalent to 720 mg apparent fecal digestible lysine per hen-day. (Key words: laying hen, requirement, feed efficiency, egg mass, lysine) 1998 Poultry Science 77: INTRODUCTION The efficiency of protein utilization depends to a large extent on the amino acid composition of the diet. The closer the amino acid composition of the diet matches the hen s requirement, the more efficient the protein of the diet is utilized. Methionine and lysine are generally first and the next limiting amino acids in corn-soybean diets for laying hens. Therefore, the efficiency of protein utilization is increased by supplementation of methionine (Schutte and Van Weerden, 1978; Schutte et al., 1983, 1984, 1994) and lysine (Van Weerden and Schutte, 1980; Uzu and Larbier, 1985). Published reports on the requirement of laying hen for lysine vary considerably. In studies by Jensen et al. (1974), Latshaw (1976), and Nathanael and Sell (1980), a requirement of 670 to 780, 650, and 700 mg/hen-d was found, respectively. The National Research Council (1994) recommends 690 mg dietary lysine/hen-d for white egg layers. Higher requirement figures were reported by Van Weerden and Schutte (1980: 860 mg/hen-d), Uzu and Larbier (1985: 800 mg/hen-d), and Al Bustany and Elwinger (1987: 820 mg/hen-d). The experiment reported herein was designed to obtain more information about the lysine requirement of a White Leghorn laying hen strain with a high laying production during the early stage of laying. Received for publication August 4, Accepted for publication December 15, To whom correspondence should be addressed: G.vandenBerg@Voeding.tno.nl 2Lohmann Holland BV, 8171 MD Vaassen, The Netherlands. MATERIALS AND METHODS Experimental Design The experiment was carried out with a White Leghorn strain of hens ( Lohmann LSL ).2 Prior to this experiment, a digestibility trial was carried out to determine the apparent fecal digestibility of amino acids of the basal diet (Table 1). Based on the results of this trial, the supplemented levels of lysine on top of the basal diet in the performance experiment were chosen. In the digestibility study, six hens 27 wk of age were involved. The hens were housed individually in cages and maintained under a commonly 16 h light:8 h dark cycle throughout. Feed as dry mash and water were consumed ad libitum. During the 8 h darkness period, feed was omitted. The digestibility trial consisted of a pretest period of 14 d and a test period of 4 d, during which period excreta were collected quantitatively per two hens separately. Only the excreta produced during the 16 h light period were used for performing the analysis. Results of a previous study (Schutte et al.; unpublished results) pointed out that there were no significant differences in digestibility when excreta were collected over a 16 h or over a 24-h period per day in a 16 h light:8 h dark cycle. In order to limit degradation, the excreta produced during the 16-h light period were collected at intervals of 4 h. In addition, the excreta produced during the period of darkness were collected separately from the excreta produced during the 16-h lighting period. Collection of night excreta was done once a day. The feed and the day 697

2 698 SCHUTTE AND SMINK TABLE 1. Composition of the basal diet used in the digestibility and performance trial Ingredients Percentage Corn Tapioca Soy oil 1.60 Soybean meal (50% CP) Corn gluten meal (60% CP) 2.00 Meat meal tankage (58% CP) 3.00 Alfalfa meal, dehydrated 3.00 Feather meal, hydrolyzed 1.00 Ground limestone 7.78 Monocalcium phosphate 1.14 Iodized salt 0.30 Vitamin-mineral mix KHCO DL-methionine 0.20 L-tryptophan 0.02 Contents Dry matter (analyzed) 89.9 Crude protein (analyzed) 16.4 ME (calculated), kcal/kg 3 2,810 Ca (analyzed) 3.52 P (analyzed) Supplied per kilogram of diet: 3.5 mg riboflavin, 30 mg niacinamide, 12 mg D-pantothenic acid, 350 mg choline chloride, 15 mg cobalamin, 1.5 mg menadione, 25 mg DL-a-tocopheryl acetate, 3.44 mg retinyl acetate, 50 mg cholecalciferol, 250 mg FeSO 4 7H 2 0, 100 mg MnO 2, 100 mg CuSO 4 5H 2 O, 150 mg ZnSO 4 7H 2 O, 0.8 mg folic acid, 0.15 mg Na 2 SeO 3 5H 2 O, 0.1 mg biotin, 100 mg antioxidant ( ethoxyquin ). 2In order to obtain a calculated base excess of 25 meq/100 g of diet. 3Values calculated from data provided by the Dutch Bureau of Livestock Feeding (1994). excreta were analyzed for the content of dry matter, N, and amino acids. The night excreta were only analyzed for the content of dry matter and used for the calculation of the total dry matter output per 24 h. In the performance experiment, birds were housed individually in wire cages in two-step batteries in a room with controlled temperature, ventilation, and lighting. The hens were placed in the cages at an age of approximately 19 wk at a lighting scheme of 14 h/d. The period of lighting was in the next 2 wk gradually increased to 16 h/d. After an adaptation period of 5 wk, groups of 15 adjacent cages containing high producing birds of similar average initial weight were formed as replicates. Four replicates of each treatment group were used in a randomized block design. The basal diet was based on corn and soybean meal (Table 1) and was adequate in all essential amino acids except lysine. The analyzed contents of CP in the basal diet used was 16.4%. DL-Methionine was added to the basal diet to obtain a dietary level of 0.43% total methionine and 0.72% total sulfur amino acids, a level found to be adequate for high laying hen performance (Schutte et al., 1994). Eight additions of lysine (0, 0.04, 0.08, 0.12, 0.16, 0.20, 0.24, and 0.28%) as L-lysine HCl to the basal diet were tested, providing at the highest supplementation rate 0.93% dietary total lysine. Based on the results of the digestibility trial, the 0.93% level of total lysine corresponds to 0.77% apparent fecal digestible lysine, assuming that digestibility of free lysine was 100%. The experimental diets were fed for a period of 12 wk (24 to 36 wk of age). The basal diet was mixed as one batch for all experimental groups. The experimental diets were prepared by splitting up the basal diet in eight subcharges, to which the required amount of lysine, as L-lysine HCl, was added and mixed. The feed ingredients were of the same batch as used in the digestibility trial. The diets were mixed freshly twice; at the start and at 6 wk during the experimental period. The basal diet of each batch was analyzed for CP, Ca, P, and amino acids. Amino acids were determined by ionexchange chromatography using the method described by Llames and Fontaine (1994). Methionine and cystine were determined by ion-exchange chromatography as methionine sulphone and cysteic acid, respectively, after oxidation with performic acid. Only small differences in the analyzed values between the two mixing batches were observed. These values agreed also very well with those analyzed in the batch used in the digestibility trial. The diets were consumed ad libitum as dry mash. Water was provided automatically via nipple drinkers, and the hens had free access to oyster shell grit via a cup. Throughout the experiment, egg production per hen, feed consumption per replicate, and mortality were measured. Mean egg weight was determined once a week by individually weighing all eggs produced on 1 d. Statistical Analysis The experimental data of the trial were analyzed by means of ANOVA fitting a randomized block design (Cochran and Cox, 1957), using the computer program SPSS/PC+V5.0 (Norusis, 1992). The significance of differences between treatment means were tested by using the least significance difference test (Snedecor and Cochran, 1980). All statements of significance are based on a probability of less than The dietary lysine requirements were estimated from egg mass production and feed:egg mass using a nonlinear regression procedure. Exponential response curves were fitted to the experimental data points using the following equation: Y = a + b [1 e c(x d)] where Y = egg mass production or feed:egg mass; a = intercept; b = maximum improvement from added L- lysine HCl; c = curvature steepness; x = dietary apparent fecal digestible lysine in the experimental diets (percentage), and d = dietary apparent fecal digestible lysine level of the basal diets (percentage). Tentative values for lysine requirements were calculated at 90% of maximum response. This value was chosen arbitrarily (Schutte and Pack, 1995). RESULTS The results of the digestibility trial are presented in Table 2. Apparent fecal digestibility of the protein

3 LYSINE REQUIREMENT OF LAYING HENS 699 bound lysine was found to be 75.6%. The performance trial went well. During the 12-wk experimental period only three birds died. Performance data of the experiment are summarized in Table 3. In the tested range of the experiment, the level of lysine had no significant effect on egg production. There were a few significant differences in egg weight (Treatment 1 vs 2, 6, and 7). A dietary content of apparent fecal digestible lysine of 0.69% gave the highest egg mass. However, egg mass at this lysine level was only significantly different from that at the lowest apparent fecal digestible lysine level of 0.49%. Feed intake was not significantly effected by the dietary lysine level. Efficiency of feed utilization for producing egg mass was affected by the level of dietary lysine. Feed utilization was significantly higher in Treatments 3 to 8 than in Treatment 1. A dietary level of 0.65% apparent fecal digestible lysine was needed for a significantly improved feed:egg mass in comparison with Treatment 2. Estimation by exponential response curves of the apparent fecal digestible dietary lysine requirement to maximize egg mass and minimize feed: egg mass was 0.49 and 0.66%, respectively (Table 4). These values correspond with an apparent fecal digestible lysine intake of 540 and 720 mg/hen-d, respectively. Lysine intake was calculated by multiplying the daily feed consumption (109 g/hen-d) by the dietary level of apparent fecal digestible lysine. DISCUSSION In estimating amino acid requirements from feeding trials, two types of methods are generally used; the TABLE 2. Contents of analyzed amino acids and the apparent fecal digestibility of amino acids of the basal diet Apparent Apparent fecal fecal Amino Total digestibility digestible acids content 1 ± SD 2 content 2 (%) Lysine ± Methionine ± Methionine + cystine ± Threonine ± Arginine ± Tryptophan ± Isoleucine ± Leucine ± Valine ± Phenylalanine ± Tyrosine ± Histidine ± Aspartic acid ± Glutamic acid ± Glycine ± Proline ± Serine ± Alanine ± Inclusive an addition of 0.20% DL-methionine and 0.02% L-tryptophan. 2As determined in the digestibility trial (mean values of six individually housed hens). linear (broken line) model and the nonlinear models. As was pointed out by Fisher et al. (1973), the use of a linear response up to a maximum level usually leads to an underestimation of requirements. On the other hand, use of curves based on exponential equations may lead to an overestimation. From a comparison of the two models, Robbins et al. (1979) concluded that the nonlinear models are preferable. However, nonlinear curves do not define a fixed requirement, which led us to the approach of deriving a tentative figure at 90% of the maximum response. Although this is an arbitrary choice, the procedure gives a good idea of the dietary amino acid level to support close to maximum performance. Based on the results for maximal efficiency of feed utilization, the estimated requirement for apparent fecal digestible lysine was 0.66%, and that of total dietary lysine 0.82%. From the results of the daily feed intake of the hens in the present study, it can be calculated that these values correspond with a total and apparent fecal digestible lysine intake of approximately 900 and 720 mg/hen-d. Due to differences in feed intake, the requirement for amino acids expressed as daily intake is a better estimation than those based on the dietary level (Gous et al., 1987). The requirement for total and apparent fecal digestible lysine to maximize egg output was estimated to be 720 and 540 mg/hen-d, respectively. Therefore in our study, the requirement based on maximum egg output was lower than on the basis of minimizing the ratio of feed to egg mass. Similar findings were reported for the estimation of the SAA requirements of laying hens (Schutte and Van Weerden, 1978; Schutte et al., 1983, 1984, 1994). In the latter studies, a lower feed intake of the hens was found at higher dietary methionine levels. According to Gous and Kleyn (1989), hens consume more feed when a marginal deficiency of specific amino acids are fed. In our experiment, the lowest feed intake was found in Treatments 4, 5, and 6, but did not differ significantly from the feed intake of the hens in the treatment group with the highest daily feed intake. When using the maximal efficiency of feed utilization to estimate the requirement for lysine, a total lysine requirement of approximately 900 mg/hen-d was found. This value is considerably higher than the recommended requirement by NRC (1994) and the estimated lysine requirement in a couple of studies in earlier reports, wherein a requirement for total lysine of 650 to 700 mg/hen-d was found (Latshaw, 1976; Nathanael and Sell, 1980). However, in these studies, hens produced an egg mass of approximately 42 g/d, which is 14 g/d lower than the production of the layers in our study. It is very likely that there is a difference in genetic potential between the high producing strain in our experiment and those of the studies of Latshaw (1976), and Nathanael and Sell (1980). Different lysine requirements between strains were also pointed out by Pilbrow and Morris (1974) in a study with eight different layer hen strains.

4 700 SCHUTTE AND SMINK TABLE 3. Effect of dietary apparent fecal digestible lysine on laying hen performance in the age period of 24 to 36 wk Treatment group 1 Variable Total dietary lysine, % Apparent fecal digestible lysine, % a cmean values within a row with no common superscript differ significantly (P < 0.05). 1Each treatment group consisted of 60 individually housed hens. 2The mean body weight of the hens at the start of the experimental period was 1,570 g for all treatment groups. SEM (df = 23) Egg production, hen-d Egg weight, g 57.4 b 58.8 a 58.5 ab 58.5 ab 58.4 ab 58.7 a 58.9 a 58.3 ab 0.39 Egg mass, g/hen-d 55.8 b 56.8 ab 56.5 ab 56.3 ab 56.8 ab 57.1 a 56.7 ab 56.6 ab 0.42 Feed intake, g/hen-d Feed intake:egg mass, g:g 1.98 a 1.97 ab 1.94 bc 1.94 bc 1.92 c 1.91 c 1.93 c 1.94 bc Weight gain, g/hen Lysine intake, mg/hen-day ,021 Apparent fecal digestible lysine intake, mg/hen-d Further, it should be noted that the requirement figure recommended by NRC (1994) is based on U.S. studies in which egg production criteria rather than feed conversion efficiency were used for estimating the lysine requirement. The same is true for the estimated lysine requirement figures of Latshaw (1976) and Nathanael and Sell (1980). In European studies, egg mass production as well as feed conversion efficiency are often taken into consideration for estimating the lysine requirement. Our estimated lysine requirement for obtaining maximum efficiency of feed utilization is in general in agreement with the European figures published by Fontaine (1974), Pilbrow and Morris (1974), Van Weerden and Schutte (1980), Uzu and Labier (1985), and Al Bustany and Elwinger (1987) of 800 to 900 mg lysine/ hen-d at an egg mass production of approximately 50 g/ hen-d. In addition, in a recent review, Joly (1995) suggested a dietary lysine intake of 880 mg/hen-d as an economic requirement at a peak production of 58 g egg mass/d. In practice egg mass production levels are often lower than those of the present study. In a review, McDonald and Morris (1985) calculated that the requirement for dietary lysine intake per hen-day changed with 10 mg/g TABLE 4. Summary of the estimated lysine requirements from exponential response curves Estimated requirements 2 Exponential Apparent fecal Variable response curve 1 Total digestible lysine (%) Egg mass y = e 475.0(x 0.49) Feed:egg mass y = e 13.93(x 0.49) 1Exponential curves are calculated on basis of the content of apparent fecal digestible lysine in the diet. 2Calculated at 90% of maximum response. egg mass yield per d. The results of the present study would mean that the calculated requirement for total lysine at an egg mass production of 50 g/d is approximately 830 mg/hen-d for hens with a body weight of approximately 1,500 g. ACKNOWLEDGMENTS This work was financially supported by Degussa AG- Germany, Eurolysine-France, and ADM Bio Products- Germany. REFERENCES Al Bustany, Z., and K. Elwinger, Response of laying hens to different dietary lysine intakes. Acta Agric. Scand. 37: Cochran, W. G., and G. M. Cox, Experimental Designs. 2nd ed. John Wiley and Sons, Inc., New York, NY. Dutch Bureau of Livestock Feeding, Chemical Composition, Digestibility and Energy Value of Feed Ingredients. Bureau of Livestock Feeding, Lelystad, The Netherlands. Fisher, C., T. R. Morris, and R. C. Jennings, A model for the description and prediction of the response of laying hens to amino acid intake. Br. Poult. Sci. 14: Fontaine, G., Effect of increasing dietary levels of methionine and lysine on laying hen performance. Landb. Tijdschrift 3: Jensen, L. S., C. H. Chang, and L. Falen, Response to lysine supplementation by laying hens fed practical diets. Poultry Sci. 53: Joly, P., An update of the amino acid needs of the laying hen. Pages in: Proceedings of the 10th World s Poultry Science Association. Conference on Poultry Nutrition. Antalya, Turkey. Gous, R. M., M. Griessel, and T. R. Morris, Effect of dietary energy concentration on the response of laying hens to amino acids. Br. Poult. Sci. 28: Gous, R. M., and F. J. Kleyn, Response of laying hens to energy and amino acids. Pages in: Recent Developments in Poultry Nutrition. D.J.A. Cole and W. Haresign, ed. Butterworths, London, UK. Latshaw, J. D., Lysine requirement of hens fed diets with corn as the major cereal grain. Poultry Sci. 55:

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