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Effect of foliage from multi-purpose trees and a leguminous crop residue on in vitro methanogenesis and ruminal N use
International Congress Series 1293 (2006) 168 – 171
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Effect of foliage from multi-purpose trees and a leguminous crop residue on in vitro methanogenesis and ruminal N use A.B. Zeleke *, C. Cle´ment, H.D. Hess, M. Kreuzer, C.R. Soliva Institute of Animal Science, Animal Nutrition, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland
Abstract. The effects of supplementing a low-quality tropical grass (Brachiaria humidicola CIAT 6133) with foliage from multi-purpose trees (MPTs; Acacia angustissima ILRI accessions 459 and 15132; Sesbania sesban ILRI 10865 and 15019, Samanea saman ILRI 14884) and a leguminous food-feed crop (Cajanus cajan ILRI 16555) on methanogenesis and N use were measured with rumen simulation technique. All supplements improved the supply of fermentable nutrients, particularly of degradable N, and improved N utilization. One accession of A. angustissima (459) and one of S. sesban (10865) were effective in limiting methanogenesis. Effects of C. cajan and S. sesban (10865) on N turnover and total methane were additive when supplemented together. Thus, this combination presents a promising choice to improve low-quality tropical diets at a limited methane emission. D 2006 Published by Elsevier B.V. Keywords: Rusitec; Tropical plant; Food–feed crop; Methane; Protein
1. Introduction The livelihood of farmers in the developing world largely depends on ruminants as they provide sustenance as milk and meat, animal traction, manure for crop production and fuel energy, cash income from sales of their products and a safety net of capital assets [1]. African ruminants subsist under poor nutritional conditions utilizing feed from poor, N-limited native pastures and crop residues. One of the feasible options for an improvement of the nutritional value of these feedstuffs to achieve higher productive performance is supplementary feeding with feed sources such as foliage from multipurpose trees (MPTs) or residues of food–feed crops with nitrogen contents higher than that of the basal forage [2]. * Corresponding author. Tel.: +251 114 338411. E-mail address: [email protected] (A.B. Zeleke). 0531-5131/ D 2006 Published by Elsevier B.V. doi:10.1016/j.ics.2006.01.017
A.B. Zeleke et al. / International Congress Series 1293 (2006) 168–171
169
Recently, interest has increased in the use of tropical plants especially as rumenmanipulating agents. Although results are not always conclusive, studies conducted so far indicated partial defaunation and methane (CH4)-suppressing effects of various MPTs [3–6]. Reducing ruminal CH4 formation might have the dual advantage of increasing production efficiency [7] and decelerating its atmospheric accumulation. In a preliminary study, various MPTs were screened for their properties to mitigate CH4 emission [8]. The MPTs most effective in this respect were Samanea saman and always one accession of Acacia angustissima and Sesbania sesban. Cajanus cajan, in turn, was found to increase ruminal ammonia concentration most of all. The objective of this study was, therefore, to evaluate the effects of foliage from these most promising MPTs and food–feed crop on ruminal methanogenesis and nitrogen utilization in a longer-term in vitro system. 2. Material and methods The in vitro rumen simulation technique Rusitec [5,6] was used consisting of eight fermenters. Based on the preliminary experiment [8], one particularly efficient and one less efficient accession each of Acacia angustissima (ILRI accessions 459 and 15132) and of Sesbania sesban (ILRI accessions 10865 and 15019) were employed, as well as Samanea saman (ILRI accession 14884). A total of eight diets (Table 1) were investigated, whereof, apart from a grass-only control (14 g dry matter (DM)/day), six diets contained 80% Table 1 Effects of MPT with and without combination with a food–feed crop (Cajanus cajan) supplemented to the lowquality tropical grass Brachiaria humidicola (n = 3)a B. humidicola
100%
80%
Supplements
–
Samanea Acacia Acacia Sesbania Sesbania Cajanus saman angustissima angustissima sesban sesban cajan
Cajanus cajan; Sesbania sesban
Accession no.
6133
14884
10865
Degradation (%) – Organic matter – NDF Methane – mmol/day – mmol/g f OM – mmol/g f NDF N use (mg/day) – Supply – Undegraded – Ammonia – Degraded but not to ammoniab
80%
15132
80%
459
80%
15019
80%
10865
80%
16555
60%
27.4d
43.3ab
39.6bc
32.7cd
45.9ab
32.9cd
46.2ab
47.3a
16.1bc
26.4abc
27.2abc
15.1c
28.5ab
19.3abc
30.6a
23.7abc
4.14a 0.71 1.67
1.47c 0.35 0.85
2.35abc 0.67 1.41 75 40d 3d 32d
3.81ab 0.69 1.60 184 50c 37c 97bc
3.17abc 0.61 1.19 173 64b 16cd 93bc
2.06bc 0.50 1.68 188 90a 14cd 84bc
183 48cd 32c 102b
198 95a 31c 73c
3.86ab 0.67 1.44 222 40d 94b 88bc
2.29bc 0.69 1.33 345 98a 117a 130a
a Means within the same row having no common letters are significantly different. f OM = apparently fermented organic matter; f NDF = apparently fermented neutral detergent fiber. b Presumed to be roughly equivalent to microbial protein.
170
A.B. Zeleke et al. / International Congress Series 1293 (2006) 168–171
(11.2 g DM/day) of Brachiaria humidicola (CIAT accession 6133), a tropical low quality grass, and 20% of the respective supplements (2.8 g DM/day). A final diet comprised S. sesban (10865) and C. cajan (ILRI accession 16555) at proportions of 20% each and 60% of the grass. Experimental runs lasted for 10 days and were replicated three times, with the last 5 days serving for data collection. The foliages differed in their composition with respect to organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and lipids, but the total DM supply was kept constant across all dietary treatments. Ruminal fluid was obtained from a rumen-fistulated Brown Swiss cow fed hay ad libitum and a small amount of concentrate. Fermenters were filled with 900ml of ruminal fluid and 100ml of McDougall buffer. Buffer flow rate was 450 ml/day. The experimental diets were supplied in nylon bags (70 140 mm2) with a pore size of 100 Am. Except on day 1, when one bag contained fresh solid rumen content, always two nylon bags filled with feed were placed in the fermenters remaining there for 48 h with one bag replaced every 24h. After removing from the fermenters, feed bags were washed in a machine with cold water and thereafter stored at 20 8C for compositional analysis. On a daily basis, fermenter fluid was taken to measure various ruminal fluid traits, among them ammonia concentration measured with a potentiometer (Model 632, Metrohem, Herisau, Switzerland). Fermentation gases were collected in gas-tight bags whereof gas volume and CH4 concentration were determined. Data were evaluated by analysis of variance [9] considering dietary treatment and run as effects. 3. Results and discussion The mean ruminal fluid pH was 6.93 (F0.065) and the redox potential averaged at 243 (F 8.3) confirming that fermentation conditions were favourable. With the exception of A. angustissima 459 which did not favour an increased NDF degradation, supplementation of the grass with the rest of the MPT foliage and/or the food–feed crop increased ( p b 0.001) the apparent degradation of the OM by 19% to 68% and the NDF by 20% to 90% compared to those found with the grass alone (Table 1). Supplementing C. cajan either alone or combined with S. sesban 10865 caused the greatest increase in digestibility. CH4 release from the fermenters numerically increased with most supplements, except with A. angustissima 459 and S. sesban 10865, the latter when supplied alone and in combination with C. cajan. However, variations in CH4 release were partially dependent on shifts in nutrient degradation as can be seen when relating CH4 to fermented organic matter ( f OM) and fiber ( f NDF). The supplements A. angustissima 15132, S. Sesban 10865, and the diet containing the two supplements numerically decreased CH4 formation per unit of f NDF. CH4 per unit of f OM was decreased with A. angustissima 459 and S. sesban 10865 (diet effect, p b 0.05). Since f OM is a good measure of feed energy content, the expected increase in performance with higher dietary f OM content at reduced CH4 formation would decrease the CH4 emissions per unit of product (milk, meat). A. angustissima 459 and S. sesban 10865 had been found superior in CH4 suppression to A. angustissima 15132 and S. sesban 15019 when tested without grass already in the previous gas test [8]. Like in the gas test, the same differences among different accessions of the same species occurred in the present study.
A.B. Zeleke et al. / International Congress Series 1293 (2006) 168–171
171
Different from the gas test [8], S. saman had no anti-methanogenic properties. C. cajan supported methanogenesis as had been expected from the supplementation of nontanniniferous legumes [5,6]. Data on the use of dietary nitrogen (Table 1) suggest that all supplements not only increased daily N supply but also N use efficiency. There were mostly more than proportionate increases in daily amounts of N recovered as ammonia and in apparently degraded N not being incorporated in ammonia. This latter fraction is roughly equivalent to N bound in microbes. All supplements led to estimated 2- to 4-fold increases in the amounts of microbial protein, as was found earlier when supplementing different forage legumes [5,6]. Effects of C. cajan and S. sesban 10865 were additive in relation to the unsupplemented control. Such a combination seems particularly favorable to be used as supplements for the improvement of tropical diets limited in utilizable dietary N [10–12]. This is confirmed by huge increases in incubation fluid ammonia concentration (from 0.2 up to 8.4 mmol/l; data not shown), as also had been found earlier with legume additions [5,6]. The present results reveal a large potential in combining residues of food–feed crops with MPT foliage in order to improve low-quality ruminant diets in the tropics and to simultaneously contribute to the goal of reducing a country’s greenhouse gas emissions. The promising accessions of the MPTs were from plant species with favorable agronomic properties having a rapid growth. The effects shown still have to be confirmed in vivo. Acknowledgement We gratefully acknowledge the access provided by the International Livestock Research Institute (ILRI), Ethiopia, to their forage banks in order to obtain most of the samples investigated here. We are grateful for the financial support of A.B. Zeleke by NIDECO, ETH Zurich, and the International Atomic Energy Agency (IAEA), Vienna. References [1] E.R. Ørskov, Reality in Rural Development Aid with Emphasis on Livestock Aberdeen, UK: Skeneprint Limited (1993). [2] P.O. Osuji, A.A. Odenyo, Anim. Feed Sci. Technol. 69 (1997) 27 – 38. [3] B. Teferedegne, et al., Anim. Feed Sci. Technol. 78 (1999) 11 – 20. [4] B. Teferedegne, The Use of Foliage from Multipurpose Trees to Manipulate Rumen Fermentation. PhD thesis, University of Aberdeen Scotland, UK, 2000. [5] H.D. Hess, et al., Anim. Feed Sci.Technol. 109 (2003) 79 – 94. [6] H.D. Hess, et al., Aust. J. Agric. Res. 54 (2003) 703 – 713. [7] G.J. McCrabb, R.A. Hunter, Aust. J.Agric. Res. 50 (1999) 1335 – 1339. [8] A.B. Zeleke, in: M. Kreuzer, C. Wenk, T. Lanzini (Eds.), Schriftenreihe Institut fu¨r Nutztierwissenschaften, Erna¨hrung-Produkte-Umwelt, ETH Zu¨rich, 26, 2005, pp. 138 – 141. [9] SAS, SAS/STAT Software, Release 6.12, SAS Institute Inc., Cary, NC, 1996. [10] R.A. Leng, Nutr. Res. Rev. 3 (1990) 277 – 303. [11] D.E. Richards, W.F. Brown, G. Ruegsegger, D.B. Bates, Anim. Feed Sci. Technol. 46 (1994) 37 – 51. [12] D.E.K.A. Siaw, P.O. Osuji, I.V. Nshali, J. Agric. Sci. Camb. 120 (1993) 319 – 330.
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Effect of foliage from multi-purpose trees and a leguminous crop residue on in vitro methanogenesis and ruminal N use A.B. Zeleke *, C. Cle´ment, H.D. Hess, M. Kreuzer, C.R. Soliva Institute of Animal Science, Animal Nutrition, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland
Abstract. The effects of supplementing a low-quality tropical grass (Brachiaria humidicola CIAT 6133) with foliage from multi-purpose trees (MPTs; Acacia angustissima ILRI accessions 459 and 15132; Sesbania sesban ILRI 10865 and 15019, Samanea saman ILRI 14884) and a leguminous food-feed crop (Cajanus cajan ILRI 16555) on methanogenesis and N use were measured with rumen simulation technique. All supplements improved the supply of fermentable nutrients, particularly of degradable N, and improved N utilization. One accession of A. angustissima (459) and one of S. sesban (10865) were effective in limiting methanogenesis. Effects of C. cajan and S. sesban (10865) on N turnover and total methane were additive when supplemented together. Thus, this combination presents a promising choice to improve low-quality tropical diets at a limited methane emission. D 2006 Published by Elsevier B.V. Keywords: Rusitec; Tropical plant; Food–feed crop; Methane; Protein
1. Introduction The livelihood of farmers in the developing world largely depends on ruminants as they provide sustenance as milk and meat, animal traction, manure for crop production and fuel energy, cash income from sales of their products and a safety net of capital assets [1]. African ruminants subsist under poor nutritional conditions utilizing feed from poor, N-limited native pastures and crop residues. One of the feasible options for an improvement of the nutritional value of these feedstuffs to achieve higher productive performance is supplementary feeding with feed sources such as foliage from multipurpose trees (MPTs) or residues of food–feed crops with nitrogen contents higher than that of the basal forage [2]. * Corresponding author. Tel.: +251 114 338411. E-mail address: [email protected] (A.B. Zeleke). 0531-5131/ D 2006 Published by Elsevier B.V. doi:10.1016/j.ics.2006.01.017
A.B. Zeleke et al. / International Congress Series 1293 (2006) 168–171
169
Recently, interest has increased in the use of tropical plants especially as rumenmanipulating agents. Although results are not always conclusive, studies conducted so far indicated partial defaunation and methane (CH4)-suppressing effects of various MPTs [3–6]. Reducing ruminal CH4 formation might have the dual advantage of increasing production efficiency [7] and decelerating its atmospheric accumulation. In a preliminary study, various MPTs were screened for their properties to mitigate CH4 emission [8]. The MPTs most effective in this respect were Samanea saman and always one accession of Acacia angustissima and Sesbania sesban. Cajanus cajan, in turn, was found to increase ruminal ammonia concentration most of all. The objective of this study was, therefore, to evaluate the effects of foliage from these most promising MPTs and food–feed crop on ruminal methanogenesis and nitrogen utilization in a longer-term in vitro system. 2. Material and methods The in vitro rumen simulation technique Rusitec [5,6] was used consisting of eight fermenters. Based on the preliminary experiment [8], one particularly efficient and one less efficient accession each of Acacia angustissima (ILRI accessions 459 and 15132) and of Sesbania sesban (ILRI accessions 10865 and 15019) were employed, as well as Samanea saman (ILRI accession 14884). A total of eight diets (Table 1) were investigated, whereof, apart from a grass-only control (14 g dry matter (DM)/day), six diets contained 80% Table 1 Effects of MPT with and without combination with a food–feed crop (Cajanus cajan) supplemented to the lowquality tropical grass Brachiaria humidicola (n = 3)a B. humidicola
100%
80%
Supplements
–
Samanea Acacia Acacia Sesbania Sesbania Cajanus saman angustissima angustissima sesban sesban cajan
Cajanus cajan; Sesbania sesban
Accession no.
6133
14884
10865
Degradation (%) – Organic matter – NDF Methane – mmol/day – mmol/g f OM – mmol/g f NDF N use (mg/day) – Supply – Undegraded – Ammonia – Degraded but not to ammoniab
80%
15132
80%
459
80%
15019
80%
10865
80%
16555
60%
27.4d
43.3ab
39.6bc
32.7cd
45.9ab
32.9cd
46.2ab
47.3a
16.1bc
26.4abc
27.2abc
15.1c
28.5ab
19.3abc
30.6a
23.7abc
4.14a 0.71 1.67
1.47c 0.35 0.85
2.35abc 0.67 1.41 75 40d 3d 32d
3.81ab 0.69 1.60 184 50c 37c 97bc
3.17abc 0.61 1.19 173 64b 16cd 93bc
2.06bc 0.50 1.68 188 90a 14cd 84bc
183 48cd 32c 102b
198 95a 31c 73c
3.86ab 0.67 1.44 222 40d 94b 88bc
2.29bc 0.69 1.33 345 98a 117a 130a
a Means within the same row having no common letters are significantly different. f OM = apparently fermented organic matter; f NDF = apparently fermented neutral detergent fiber. b Presumed to be roughly equivalent to microbial protein.
170
A.B. Zeleke et al. / International Congress Series 1293 (2006) 168–171
(11.2 g DM/day) of Brachiaria humidicola (CIAT accession 6133), a tropical low quality grass, and 20% of the respective supplements (2.8 g DM/day). A final diet comprised S. sesban (10865) and C. cajan (ILRI accession 16555) at proportions of 20% each and 60% of the grass. Experimental runs lasted for 10 days and were replicated three times, with the last 5 days serving for data collection. The foliages differed in their composition with respect to organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and lipids, but the total DM supply was kept constant across all dietary treatments. Ruminal fluid was obtained from a rumen-fistulated Brown Swiss cow fed hay ad libitum and a small amount of concentrate. Fermenters were filled with 900ml of ruminal fluid and 100ml of McDougall buffer. Buffer flow rate was 450 ml/day. The experimental diets were supplied in nylon bags (70 140 mm2) with a pore size of 100 Am. Except on day 1, when one bag contained fresh solid rumen content, always two nylon bags filled with feed were placed in the fermenters remaining there for 48 h with one bag replaced every 24h. After removing from the fermenters, feed bags were washed in a machine with cold water and thereafter stored at 20 8C for compositional analysis. On a daily basis, fermenter fluid was taken to measure various ruminal fluid traits, among them ammonia concentration measured with a potentiometer (Model 632, Metrohem, Herisau, Switzerland). Fermentation gases were collected in gas-tight bags whereof gas volume and CH4 concentration were determined. Data were evaluated by analysis of variance [9] considering dietary treatment and run as effects. 3. Results and discussion The mean ruminal fluid pH was 6.93 (F0.065) and the redox potential averaged at 243 (F 8.3) confirming that fermentation conditions were favourable. With the exception of A. angustissima 459 which did not favour an increased NDF degradation, supplementation of the grass with the rest of the MPT foliage and/or the food–feed crop increased ( p b 0.001) the apparent degradation of the OM by 19% to 68% and the NDF by 20% to 90% compared to those found with the grass alone (Table 1). Supplementing C. cajan either alone or combined with S. sesban 10865 caused the greatest increase in digestibility. CH4 release from the fermenters numerically increased with most supplements, except with A. angustissima 459 and S. sesban 10865, the latter when supplied alone and in combination with C. cajan. However, variations in CH4 release were partially dependent on shifts in nutrient degradation as can be seen when relating CH4 to fermented organic matter ( f OM) and fiber ( f NDF). The supplements A. angustissima 15132, S. Sesban 10865, and the diet containing the two supplements numerically decreased CH4 formation per unit of f NDF. CH4 per unit of f OM was decreased with A. angustissima 459 and S. sesban 10865 (diet effect, p b 0.05). Since f OM is a good measure of feed energy content, the expected increase in performance with higher dietary f OM content at reduced CH4 formation would decrease the CH4 emissions per unit of product (milk, meat). A. angustissima 459 and S. sesban 10865 had been found superior in CH4 suppression to A. angustissima 15132 and S. sesban 15019 when tested without grass already in the previous gas test [8]. Like in the gas test, the same differences among different accessions of the same species occurred in the present study.
A.B. Zeleke et al. / International Congress Series 1293 (2006) 168–171
171
Different from the gas test [8], S. saman had no anti-methanogenic properties. C. cajan supported methanogenesis as had been expected from the supplementation of nontanniniferous legumes [5,6]. Data on the use of dietary nitrogen (Table 1) suggest that all supplements not only increased daily N supply but also N use efficiency. There were mostly more than proportionate increases in daily amounts of N recovered as ammonia and in apparently degraded N not being incorporated in ammonia. This latter fraction is roughly equivalent to N bound in microbes. All supplements led to estimated 2- to 4-fold increases in the amounts of microbial protein, as was found earlier when supplementing different forage legumes [5,6]. Effects of C. cajan and S. sesban 10865 were additive in relation to the unsupplemented control. Such a combination seems particularly favorable to be used as supplements for the improvement of tropical diets limited in utilizable dietary N [10–12]. This is confirmed by huge increases in incubation fluid ammonia concentration (from 0.2 up to 8.4 mmol/l; data not shown), as also had been found earlier with legume additions [5,6]. The present results reveal a large potential in combining residues of food–feed crops with MPT foliage in order to improve low-quality ruminant diets in the tropics and to simultaneously contribute to the goal of reducing a country’s greenhouse gas emissions. The promising accessions of the MPTs were from plant species with favorable agronomic properties having a rapid growth. The effects shown still have to be confirmed in vivo. Acknowledgement We gratefully acknowledge the access provided by the International Livestock Research Institute (ILRI), Ethiopia, to their forage banks in order to obtain most of the samples investigated here. We are grateful for the financial support of A.B. Zeleke by NIDECO, ETH Zurich, and the International Atomic Energy Agency (IAEA), Vienna. References [1] E.R. Ørskov, Reality in Rural Development Aid with Emphasis on Livestock Aberdeen, UK: Skeneprint Limited (1993). [2] P.O. Osuji, A.A. Odenyo, Anim. Feed Sci. Technol. 69 (1997) 27 – 38. [3] B. Teferedegne, et al., Anim. Feed Sci. Technol. 78 (1999) 11 – 20. [4] B. Teferedegne, The Use of Foliage from Multipurpose Trees to Manipulate Rumen Fermentation. PhD thesis, University of Aberdeen Scotland, UK, 2000. [5] H.D. Hess, et al., Anim. Feed Sci.Technol. 109 (2003) 79 – 94. [6] H.D. Hess, et al., Aust. J. Agric. Res. 54 (2003) 703 – 713. [7] G.J. McCrabb, R.A. Hunter, Aust. J.Agric. Res. 50 (1999) 1335 – 1339. [8] A.B. Zeleke, in: M. Kreuzer, C. Wenk, T. Lanzini (Eds.), Schriftenreihe Institut fu¨r Nutztierwissenschaften, Erna¨hrung-Produkte-Umwelt, ETH Zu¨rich, 26, 2005, pp. 138 – 141. [9] SAS, SAS/STAT Software, Release 6.12, SAS Institute Inc., Cary, NC, 1996. [10] R.A. Leng, Nutr. Res. Rev. 3 (1990) 277 – 303. [11] D.E. Richards, W.F. Brown, G. Ruegsegger, D.B. Bates, Anim. Feed Sci. Technol. 46 (1994) 37 – 51. [12] D.E.K.A. Siaw, P.O. Osuji, I.V. Nshali, J. Agric. Sci. Camb. 120 (1993) 319 – 330.