|Livestock Research for Rural Development 27 (8) 2015||Guide for preparation of papers||LRRD Newsletter||
Citation of this paper
Biomass yield, chemical composition and in vitro organic matter digestibility (IVOMD) of cultivated stinging nettle (Urtica simensis) were determined from four different locations cut at early, mid and late flowering stages between February and March, 2013.
Increasing trends of DM yield , Ash, EE, ADF, NDF and ADL contents but decreasing trend of CP content and IVOMD were noted with increasing stages of maturity. Maximum DM yield (10.8t/ha), high NDF (407g/kgDM) and lower CP content (243g/kgDM) and IVOMD (63.1%) were observed at late flowering stage and maximum CP content (277g/kg DM) and IVOMD (78.5%) at early flowering stage. The cell wall components (ADF, ADL and NDF) were negatively correlated with both protein content and IVOMD. On the other hand, there was positive relationship between protein content and IVOMD. Among four experimental locations high protein content (277g/kgDM) and IVOMD (78.5%) was obtained in Bore area. The protein content and IVOMD varied from 277g/kgDM and 78.5% at early flowering stage to 243g/kgDM and 63.1% at late stage of maturity respectively. Hence the whole stinging nettle could be used to buffer protein deficiencies and improve digestibility in animal ration.
Keywords: cell wall components, DM yield, flowering stages
Natural pastures are among the major feed resources for livestock industry in Ethiopia. In the current state of management most of these pastures, do not offer sufficient nutrition and would rarely meet the livestock requirement. The potential for the adoption of improved forage is high because of the possible opportunity for regular cash income generation from animal product sales fed with such forages. But currently the actual benefit obtained is minimal because forage cropping is in direct competition with current cash and subsistence cropping enterprises. Commercial concentrate feeds are not readily available and expensive and thus are rarely used by small scale farmers (Mengistu 2005). Moreover in developing countries, such as Ethiopia, grain, which forms the bulk of concentrate feeds for livestock, is both in short supply and expensive due to direct competition with human food uses (Negesse et al 2009). Hence ensuring the availability and quality of feed is essential for improving the productivity of the livestock industry in Ethiopia (Negesse et al 2009). Thus alternate feeds should be assessed which could partly fill the gap in the feed supply, decrease competition for food between humans and animals, reduce feed cost, and contribute to self-sufficiency in nutrients from locally available feed sources.
Stinging nettle (Urtica simensis) is one of the less-used forage, though has a long-standing reputation as potential forage for animals. The herb is believed to be completely non-toxic. It contains iron, calcium, phosphorus, potassium, sulphur, magnesium and it is also rich in A, C, K D, and B vitamins. It contains up to 20% mineral salts, mainly salts of calcium, potassium, silicon, and nitrates. Nettle extract has been found to contain all of the essential amino acids (Mishra 2006).
In Ethiopia few research works have been conducted on the geographical distribution and medicinal uses of stinging nettle. In some highlands of Ethiopia Urtica simensis is used as wild vegetable source (Tsegaye et al 2008; Getachew et al 2013). Recent studies conducted in the northern highlands of Ethiopia on the nutritional importance of stinging nettle indicated that the forage is rich in protein (29% CP) and has 65-75% IVOMD (Yeheyis et al 2008). This nutritional status of the forage attracts researchers for further agronomic and animal evaluation (Yeheyis et al 2008).
The fodder quality of animal feed is influenced by such factors as type of plant, plant density and harvesting time. Stage of maturity is the most important factor determining animal forage quality. It is a usual trend that animal forage quality decreases with advancing maturity because maturity of forage influences its digestibility and consumption by animals (Ball et al 2001). Generally, fiber concentration of the forage crops increases while quality and digestibility decrease as aging prolongs (Ball et al 2001). Studies on some tropical legume forages showed that DM yield increase with advancing stages of maturity . On the contrary the nutritive value of the forage gradually declines as the plant matures (Bayble et al 2007; Baloyi et al 2008).
However, studies on the forage quality of Stinging nettle including the effect of harvesting stage of the forage on dry matter (DM), crude protein (CP), neutral and acid detergent fibers (NDF and ADF) are not addressed yet in Ethiopian condition. Hence determination of the appropriate harvesting time is a crucial factor for a successful forage production. Therefore the study was conducted to asses forage yield and quality of cultivated stinging nettle at three stages of maturity.
The study was conducted in Kofele, Aleta-Wendo, Hula and Bore districts, southern Ethiopia (Figure 1). Kofele is located between 7°06′ to 7°24N′ and 38°45′ to 38°78′E, with an average altitude of 2695 meters above sea level (masl); Aleta-Wendo between 6°36′ to 6°72′N and 38°25′ to 38°56′E, with an average altitude of 2037 masl; Hula between 6°29′ to 6°74′N and 38°31′ 38°77′E, with an average altitude of 2759 masl; and Bore between 9°22' to 9°38' N and 35° 31' to 35° 53'E with an average altitude of 1851. The soil type of all four locations is Nitosols (FAO 1984).
|Figure 1. Map of the study area|
Rhizomes, which were made from root cuttings, were collected from naturally available wild stinging nettle at each of respective four experimental areas. Experimental fields were hand dug at three different times and whole plots for each site were prepared. Planting were established in a bed system in which experimental plots with plot size of 2m x 1m were prepared and arranged in a randomized complete block design against the slope gradient of the land. Rhizomes (approximately 5-9cm length) were planted on established plots (beds) in 9 replicates arranged in three blocks and each block contains 3 plots in a row. The space between plots (beds) as well as between rows was 1m. Rhizomes were planted in 10cm spacing from each other.
|Photo 1. Stinging nettle (Urtica simensis) plant|
Planting was done in September 2012. Seedling counts was made at eight weeks after planting. The total numbers of seedlings in a row were counted to determine plant density per square meter (Tarawali et al 1995). Plots were monitored for early, 50% (mid) and >75% (late) flowering of the plant. Harvesting were carried out at three different times considering flowering stage between February and March 2013. At each of the three flowering stages half of three plots across the three blocks within the same column were harvested out of nine plots by cutting approximately at 10–15cm above the ground. Fresh plant material was weighed and recorded just after cutting for individual plots and sub-samples were taken in triplicate separately and sealed in plastic bag to determine the dry-matter yield and retained for further laboratory analysis.
Samples collected at three stage of maturity were weighed, and chopped into small pieces and dried in a forced air draft oven at 65o C to a constant weight, and then was ground in a hammer mill (Arthur H. Thomas Company, Philadelphia PA., U.S.A.) with a 1mm screen. Dry matter (DM), ash, ether extract (EE) and crud protein (CP) were analyzed according to AOAC (2005). Analysis for neutral detergent fiber (NDF) was performed using the procedures described by Van Soest et al (1991). Acid detergent fiber (ADF) and acid detergent lignin (ADL) were analyzed using the procedures described by Van Soest and Robertson (1985).
In vitro ruminal organic matter digestibility was determined according to the procedure of Tilley and Terry (1963). Ruminal fluid was collected using rumen tubes from local breed (Arsi-Bale) rams in the afternoon (6 hours after they were offered Rhodes grass hay). Rumen digesta was collected into a pre-warmed thermos flask. McDougall’s buffer (based on the composition of sheep saliva) was prepared.
Approximately 0.5 gram of milled forage samples were weighed into 50 ml centrifuge tubes. McDougall’s buffer (based on the composition of sheep saliva) and ruminal fluid were added, and tubes were incubated in water bath for 48h at 39°C. Four blank tubes containing ruminal fluid and buffer without feed sample were included. Centrifuge tubes were agitated manually three times per day. Fermentation was stopped after 48h, and acidified pepsin was added. Then tubes were incubated in water bath for another 48h at 39°C. The contents were then filtered and the residue dried and weighed. After drying, residue was ashed. In vitro ruminal organic matter digestibility was determined as the quantity of OM lost during fermentation and subsequent pepsin digestion. All laboratory experiments were carried out at Hawassa University, Animal Nutrition Laboratory.
Statistical analyses were performed using the GLM procedure of the IBM SPSS Statistics 20 (2011). The model used for the analysis was:
Yijk = μ + Ai + Bj + A* B(ij) + e(kij) where Y is the parameter studied μ is the overall mean, Ai is the fixed location effect (i = 1, 2 , 3and 4), Bj is the fixed stage of maturity effect (j = 1, 2, and 3), A*B(ij) is the interaction between location and stage of maturity and e(kij) is the error term. Mean were compared using least significant differences (LSD) and significance was declared at P < 0.05.
|Table 1. The effect of location and stage of maturity on plant density and DM yield of cultivated stinging nettle forage.|
|Location||Flowering stage||Biomass yield|
|DM yield (g/plant)||DM yield
(N° of plants/m²)
|*Means within a column with different superscripts differ at p < 0.5|
The effect of location and stage of maturity on plant cover, and dry matter yield is presented in Table 1. Dry matter yield was not significantly different (P < 0.05) among three (Hula, Aleta-Wendo, and Kofele) locations. On the other hand DM yield at Bore was significantly different (p<0.05) from the rest three locations. However DM yield per plot was significantly different (P < 0.05) among three stages of maturity. Hence highest DM yield were recorded at late flowering stage and the lowest were at early flowering stage. Considering stage of maturity , DM yield was highest at late flowering in which the highest record was for Aleta-Wendo and Kofele, followed by Bore and the lowest was recorded in Hula at the same stage of maturity. On the other hand the least DM yield was observed at early flowering stage (P < 0.05) in which the lowest was for Kofele and relatively higher for Hula.
In the same way DM yield per plant was significantly different (P < 0.05) among three stages of maturity even though location had no effect on the DM yield per plant. DM yield per plant was increased as the stage of maturity advanced. The highest record was at Bore at late flowering stage and the lowest was at Hula at early stage of maturity. The plant stand count for all four locations were not significantly different (P < 0.05).
|Table 2. Effect of stage of maturity and location on chemical composition of cultivated stinging nettle|
|DM= dry matter, CP = crude
protein, EE= ether extract, NDF = neutral
detergent fibre, ADF = acid detergent fibre, ADL
= acid detergent lignin, IVOMD=in vitro organic matter
digestibility, SEM= standard error of mean,
*Means within a colmun with different superscripts differ at p < 0.5
The effect of stage of maturity and location on chemical composition of cultivated stinging nettle is presented in Table 2. Statistically there was no difference in chemical composition among the four different locations at any of similar stages of maturity except ash content, fat content (EE), acid detergent fiber (ADF) and in-vitro organic matter digestibility (IVOMD). Ash content at Bore was significantly different (P <0.05) from the rest three location, as lowest recorded was observed at this location. However there was no difference in ash contents among the rest three locations. EE composition at Bore was significantly different (P <0.05) from Aleta-Wendo, but the rest two were similar to the others. Lowest record was observed at Hula and the highest was at Kofele. The CP content at Bore was significantly different from Hula and Aleta-Wendo and IVOMD from this location was significantly different from Kofele. However, the highest DM percentage was observed in Aleta-Wendo and the lowest was observed in Kofele at early stage of flowering. The range of differences between the two locations at early flowering stage was 0.85 per cent which was the highest among all observations as well as across all four locations. On the other hand DM yield was significantly different (P < 0.05) among the three stages of maturity. Highest yield was recorded at late flowering stage in Aleta-Wendo and the lowest was in Kofele at early flowering stages.
Ash content was significantly low (P < 0.05) in Bore comparing all four locations regardless of stage of maturity . However no significant difference was recorded among the other three locations. Considering stage of maturity there was significant difference (P < 0.05) among the three stages of maturity in all four locations. The highest ash content was observed in Kofele a late flowering stage and the lowest was in bore at early flowering stage.
Crude protein (CP) yield was significantly different (P < 0.05) among three stages of maturity across four locations. The highest record was observed for Kofele at early flowering stage and lowest for Bore at late flowering stage. But there was no significant difference in CP content across four locations unlike stage of maturity.
Crude fat (EE) content was highest (P< 0.05) for Hula at late flowering stage and the lowest observation were recorded in Hula and Kofele at early stage of flowering. Content of EE was statistically similar among all four locations however it was significantly different (P< 0.05) among three stages of maturity regardless of location. Contents of ADF, NDF, and ADL are statistically different (P< 0.05) among three stages of maturity but there was not among four locations. The ADF content was highest (P < 0.05) for Kofele at late flowering stage and the lowest observation was recorded in Hula at early stage of flowering. Neutral detergent fiber (NDF) was highest (P < 0.05) in Aleta-Wendo for late flowering stage and the lowest was in Bore for early flowering stages. Acid detergent lignin (ADL) content was highest (P < 0.05) in Aleta-Wendo for late flowering stage and lowest in Bore for early flowering stage.
The in-vitro organic matter digestibility (IVOMD) result showed that significant differences (P< 0.05) observed among the three stage of maturity. Highest IVOMD was recorded at early stage of maturity followed by mid and the least is at late stage of maturity. Among four experimental locations, the result of Hula was significantly different from Bore and Aleta-Wendo. The results of other locations were not different one from another.
|Table 3. Correlation coefficient among cell wall components, protein and digestibility|
|CP = crude protein, NDF = neutral detergent fibre,
ADF = acid detergent fibre, ADL = acid detergent lignin,
IVOMD=in vitro organic matter digestibility
*p < 0.05)
The cell wall components (ADF, ADL and NDF) were negatively correlated (P< 0.05) with both protein content and IVOMD. On the other hand there was positive relationship between protein content and IVOMD. Among cell wall components, ADL highly affect the extent of IVOMD negatively, followed by NDF and ADF.
In this study the stage of maturity of stinging nettle highly affected chemical composition and influenced OM digestibility. Dry matter (DM) yield, ash, crude fat (EE), ADF, NDF and ADL contents of the forage were increased (P < 0.05) with advancing stages of maturity. However, crude protein (CP) content and IVOMD were decreased (P < 0.05) as the stage of maturity increased. Samples harvested at early flowering stages were less fibrous with high protein content and high IVOMD than late flowering stages.
The increase in DM yield with advanced stage of maturity obtained in this study agrees with earlier report on DM yield of cultivated stinging nettle in a green house in which DM yield was increased with increasing harvesting year and fertilization (Biesiada 2009). Studies by Kleitz et al (2008) on total DM yield of transplanted stinging nettle plant indicted that total DM yield was increased as harvesting year increased. Guil-Guerrero et al (2003) found that DM content of matured leaves of stinging nettle harvested at late stage of maturity was higher than young leaves harvested at early stage of maturity.
This study also coincides with other studies conducted on different forage species. Ansah et al (2010) reported the increase in DM yield, ADF, NDF and ADL and decrease in CP content with increase in harvesting day of cultivated Napier grass. Similarly Edwards et al. (2012) reported that DM yield increased with increasing cutting intervals for L. leucocephala and T. gigantea Ammar et al (2010) also reported that DM yield increased with increasing stage of maturity of Vetch.
However the total dry matter yield in this study was much less than what is reported by Kleitz et al (2008). As it is reported in the same work slow growth of stinging nettle exhibited in the first year and significant improvement was recorded on the second and third year of development. Hence the observed reduction in DM yield is possibly related to age of the plant. Grevsen et al (2008) also reported that DM content was increased as harvesting time increased for two consecutive years but in decreasing rate at the third year of harvest.
In this study the fiber contents of cultivated stinging nettle including NDF and ADF were at increasing trend as stage of maturity advanced. This result is supported by different studies on other legumes. Christensen et al. (2003) reported that NDF and ADF content of Alfa-Alfa forage was increased as stage of maturity advanced. Sultan et al (2009) also found that the NDF and ADF contents of stinging nettle plant and other similar herbs were lower in vegetative leaves than mature leaves, as structural constitutes increased in relation to advancing maturity. This result also supported by the finding Baloyi et al (2008) who studied on the dynamics of fiber content of Desmodium uncinatum in relation to stage of maturity.
The CP contents of cultivated stinging nettle recorded in this study dropped down as the stages of maturity increased. The highest CP value was recorded at early stage of maturity. Similar findings were reported by Sultan et al (2009) who reported a decline in CP contents of leaves of stinging nettle and other herbs as maturity of the plants advanced. Katoch et al (2013) who work on Setaria (Setaria anceps Stapf.) also reported that CP content decreased with advancement of plant growth.
The in-vitro organic matter digestibility (IVOMD) in this study also showed a significant variation among different stages of maturity . Maximum IVOMD was observed at early stage of maturity and decline with the advancement of stages of maturity. This result is supported by the works of Christensen et al (2003), Sultan et al (2009) and Katoch et al (2013) who reported the decline in IVOMD of different legumes as the maturity of plants increased.
In the present study the extent of in vitro organic matter digestibility (IVOMD) was affected by both cell wall and protein constitutes. As the stage maturity advanced the cell wall constitutes including ADF, ADL and NDF were increased and protein content decreased along with this the degree of IVOMD was affected negatively. Among the cell wall components, ADL showed the highest negative correlation with IVODM. The composition and structure of the cell wall usually affect digestibility to a greater extent than its content, depending on its degree of lignification (Van Soest 1994; Ammar et al 2004), and resulting in higher negative correlations of the in-vitro organic matter digestibility with ADL than with NDF and ADF content. The results of this study are related with the work of Ammar et al (2004), who studied on Spanish browse species, that exhibited a negative correlation between IVOMD and both ADF and ADL. In a research work on nutrients content and yield of Napier grass sole or in association with desmodium or lablab, Bayble et al (2007) reported that the CP and IVDMD were positively correlated , whereas their correlation with the cell wall fractions were negative.
As it is shown in figure 2 CP content is negatively correlation with advancing maturity. At early flowering stage the overall average crude protein content was 276 g/kg DM, whereas in mid flowering stage it was 250 g/kg DM and that of late flowering stage was 245 g/kgDM. The decline in CP content with advancing stage of maturity is due accretion of higher proportion of NDF corresponding to plant growth. The NDF and ADF content were higher at late maturity in which the structural constitute of the plant proportionally higher than cell contents. Similar findings were reported by Sultan et al (2009) who reported the decline in CP content and rise in NDF and ADF content of stinging nettle leaves as maturity of the plant increased.
|Figure 2. Crude Protein, NDF and ADF contents of cultivated stinging nettle in relation to stage of maturity|
As depicted on figure 2 there was a significant increase in NDF and ADF with advancing stages of maturity. Both NDF and ADF contents linearly increased with advance in stage of maturity (r² = 0.89 and 0.87, respectively). Structural cell wall components increase as plant gets matured because photosynthesis components are converted to structural components at the expense of soluble carbohydrates (Ammar et al 2010).
The authors would like to gratefully acknowledge the financial support of Development Partnerships in Higher Education (DelPHE) of British Council. The Authors also gratefully acknowledge Desalegn Mamo, for his contribution in producing the map of the study area used in this paper.
Ammar H, López S and Andrés S 2010 Influence of maturity stage of forage grasses and leguminous on their chemical composition and in vitro dry matter digestibility. In: Porqueddu C. (ed.), Ríos S.(ed.). The contributions of grasslands to the conservation of Mediterranean biodiversity. Zaragoza: CIHEAM / CIBIO / FAO / SEEP, 2010. p.199-2 03.
Ammar H, López S, González J S and Ranilla M J 2004 Chemical composition and in-vitro digestibility of some Spanish browse plant species. Journal of the Science of Food and Agriculture, 84(2):197–204.
AOAC 2005 Official Methods of Analysis of the Official Analytical Chemists, 18th Edn. (Horwitz, W., Eds.), Association of Official Analytical Chemists, Washington DC.Asfaw Z. & Tadesse M. , 2001. Prospects for sustainable use and development of wild food plants in Ethiopia. Economic Botany 55(1): 47–55.
Ansah T, Osafo E L K and Hanne H H 2010 Herbage yield and chemical composition of four varieties of Napier (Pennisetum purpureum) grass harvested at three different days after planting Agric. Biol. J. N. Am., 2010, 1(5): 923-929.
Baloyi J J, Ngongoni N T and Hamudikuwanda H 2008 Chemical composition and ruminal degradability of cowpea and silverleaf desmodium forage legumes harvested at different stages of maturity.Tropical and Subtropical Agroecosystems , 2008, 8 (Sin mes) : from http://www.redalyc.org/articulo.oa?id=93980107.
Bayble T, Melaku S and Prasad N K 2007 Effects of cutting dates on nutritive value of Napier (Pennisetum purpureum) grass planted sole and in association with Desmodium (Desmodium intortum) or Lablab (Lablab purpureus). Livestock Research for Rural Development. Volume 19, Article #11. From http://www.lrrd.org/lrrd19/1/bayb19011.htm.
Biesiada A, Wołoszczak E, Sokół-Łętowska A, Kucharska A Z and Nawirska-Olszańska A 2009 The effect of nitrogen form and dose on yield, chemical composition and antioxidant activity of stinging nettle (Urtica dioica L.) KERLA ROLONICA 55: No 3 2009.
Edwards A, Mlambo V, Lallo C H O and Garcia G W 2012 Yield, chemical Composition and In Vitro Ruminal Fermentation of the Leaves of Leucaena leucocephala, Gliricidia sepium and Trichanthera gigantea as Influenced by Harvesting Frequency J Anim Sci Adv 2012, 2(Suppl. 3.2): 321-331.
FAO 1984 Provisional Soil Map of Ethiopia. Land Use Planning Project. Addis Ababa, Ethiopia.
Getachew E A, Desse G H and Addis G D 2013 Nutritional Profile Of Samma (Urtica simensis Steudel) Leaves Grown In Ethiopia, IJSID, 2013, 3 (1), 153-160.
Grevsen K, Frette X C and Christensen L P 2008 Concentration and composition of flavonol glycosides and phenolic acids in aerial plants of stinging nettles (Urtica dioica) are affected by nitrogen fertilization and by harvest time, Europ. J. Hort. Sci. 2008, 73 (1): 20-27.
IBM SPSS Statistics for Windows 2011 Version 20.0., Armonk, NY: IBM Corp.
Kathryn M K, Marisa M W, Constance L F, Charles A M, Marta D R and Steven J G 2008 Stand Establishment and Yield Potential of Organically Grown Seeded and Transplanted Medicinal Herbs.
Katoch R, Thakur M and Kumar N 2013 Effect of morphological stage and clipping intervals of Tall fescue (Festuca arundinacea Schreb.) and Setaria (Setaria anceps Stapf.) on biochemical composition and in vitro dry matter digestibility in mid hill Himalayan region. African Journal of Agricultural Research, Vol. 8(19), pp. 2183-2188, 23 May. 2013.
Mengistu A 2005 Feed resources base of Ethiopia Status and opportunities for integrated development. Pp. 377 – 386. Proceedings of the 12th Annual Conference of the Ethiopian Society of Animal Production (ESAP). Addis Ababa, Ethiopia, August 12 – 14, 2004, ESAP (Ethiopian Society of Animal Production).
Mishra U K, Kanesh J S, Mandal A K, Das R K, Rayaguru K and Parija S C 2006 Potentials of herbal galactogogues in milk production in ruminants, The Indian Cow(9) July-Sept, 2006.
Negesse T, Makkar H P S and Becker K 2009 Nutritive value of some non-conventional feed resources of Ethiopia determined by chemical analyses and an in vitro gas method, Animal Feed Science and Technology 154 (2009) 204–217.
Tsegaye W, Urga K and Asres K 2008 Antidiabetic Activity of Samma (Urtica simensis Hochst. ex. A. Rich.) in Streptozotocin-Induced Diabetic Mice. Ethiop Pharm J 27, 75-82.
Tarawali S A, Tarawali G, Larbi A and Hanson J 1995 Methods for the Evaluation of Legumes, Grasses and Fodder Trees for Use as Livestock Feed. ILRI Manual 1. ILRI (International Livestock Research Institute), Nairobi, Kenya. pp. 51.
Tilley J M A and Terry R A 1963 A two-stage technique for the in vitro digestion of forage crops. J. Brit. Grassland Soc. 18:104-111.
Van Soest P J, Robertson J B and Lewis B A 1991 Methods for dietary fiber, nutral detergent fiber and non-starch carbohydrates in relation to animal nutrition, J. Dairy Science 74: 3583-3597.
Van Soest P J 1994 Nutritional Ecology of the Ruminant. (2nd ed.) C. U. Press, Ithaca,NY.
Van Soest P J and Robertson J B 1985 Analysis of forages and fibrous foods. A Laboratory Manual for Animal Science 613, Cornell University, USA.
Westfall R E 2003 Galactogogue herbs: a qualitative study and review. Canadian Journal of Midwifery Research and Practice, 2(2):22-27).
Yeheyis L, Tsegahun A, Sebsibe A, Mekonen T, Ziku N and Amane A 2008 Identified indigenous feed resources and their nutritive value in Menz-Gera district of Amhara region, Proceedings of the 3rd Annual Regional Conference on Completed Livestock Research Activities, 1 - 4 September, 2008. Pp 1-10.
Received 13 May 2015; Accepted 4 July 2015; Published 1 August 2015
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