ORIGINAL ARTICLE
Combination of the underutilised legumes Canavalia ensiformis (L.) D.C. and Canavalia ensiformis (L.) D.C. with sorghum: integrated assessment of their potential as conserved ruminant feed
Combinación de sorgo con las leguminosas subutilizadas Canavalia ensiformis (L.) D.C. y Mucuna pruriens (L.) DC: evaluación integrada de sus potenciales como alimento conservado para rumiantes
R. Lima-Orozco,I,II,III I. Van Daele,III U. Álvarez-Hernández,II,IV V. Fievez,III
]]> IUniversidad Central “Marta Abreu” de Las Villas (UCLV), Department of Veterinary Medicine and Zootechny, Carretera a Camajuaní km 6 ½, 54830 Santa Clara, Cuba.
ABSTRACT
The present research studied the integrated assessment of the potential as conserved ruminant feed of combined sorghum-Jack bean or Velvet bean.Data of whole plant sorghum silage supplemented with dry beans of Jack beans (JB) and whole plant sorghum-Jack beans silage or whole plant sorghum-Velvet bean (VB) silage from Lima-Orozco et al. (2014) were used to assess the integration of agronomic considerations in an overall evaluation including biomass production, nutritive value and conservation quality. The metabolisable energy (ME) content of the combined sorghum-JB silages was 1.26 times greater than the ME content of pure sorghum silage supplemented with dry beans from JB. Additionally a greater amount of protein digestible in the small intestine (dCPSI) was observed (62.9 vs 43.5 g/kg DM). It was concluded that the ME content and dCPSI of the sorghum-JB silages are 1.26 or 1.44 times higher than sorghum-JB silage or for pure sorghum silage supplemented with dry beans from JB. Moreover, a much larger surface is required for the sorghum silage and dry JB alternative. Hence, combined sorghum-JBsilage seemed the best alternative studied here in terms of DM yield, dCPSI and ME supply.
Key words: sorghun, seasonal legumes, silage.
RESUMEN
]]> Esta investigación estudió la evaluación integrada del potencial como alimento conservado para rumiantes de la combinación sorgo-canavalia o mucuna. Se utilizaron los datos del ensilaje de la planta entera de sorgo suplementada con granos secos de canavalia y el ensilaje de la planta entera de sorgo-canavalia o el ensilaje de la planta entera de sorgo con mucuna según Lima-Orozco et al. (2014) para evaluar la integración de las consideraciones agronómicas en la evaluación general que incluyó producción de biomasa, valor nutritivo y calidad de la conservación. La energía metabolizable (EM) de los ensilajes combinados de sorgo-canavalia fue 1.26 veces mayor que el contenido de EM del ensilaje de sorgo puro supplementado con granos secos de canavalia. Adicionalmente, se observó una mayor cantidad de proteína digerible en el intestino delgado (dPBID) (62.9 vs. 43.5 g/kg MS). Se concluye que el contenido de EM y dPBID de los ensilajes de sorgo-canavalia son 1.26 o 1.44 veces superiores que el ensilaje de sorgo-canavalia o para el ensilaje de sorgo puro con granos secos de canavalia. Por otra parte, se requiere una superficie mayor para el ensilaje de sorgo y la alternativa de granos secos de canavalia. Por tanto, la combinación del ensilaje de sorgo-canavalia pareció la mejor alternativa estudiada aquí en términos de MS, rendimiento, dPBD and suministro de EM.Palabras clave: sorghun, leguminosas, ensilage.
INTRODUCTION
In tropics, grasses have been, by tradition and for practical point of view, the most used forage for conservation. However, recently legumes (herbaceous and woody) become more important in ruminant feeding. Despite their importance, few studies have been carried out to assess their application in practice(Ojeda, 2000). In previous reports the potential of ensiled sorghum (Sorghum bicolor (L.) Moench)-soybean (Glycine max. L. Merril)(Lima-Orozco et al. 2013) and sorghum-Jack bean (Canavalia ensiformis (L.) DC.) or sorghum-Velvet bean (Mucuna pruriens (L.) (Lima-Orozco et al.2014) as a ruminant feed were shown. However, has not been reported an integration of agronomic considerations in an overall evaluation including biomass production, nutritive value and conservation quality. Hence, the aim of the present research was to study the integrated assessment of the potential as conserved ruminant feed of combined sorghum-Jack bean or Velvet bean.
MATERIALS AND METHODS
Data of whole plant sorghum silage supplemented with dry beans of Jack beans (JB) and whole plant sorghum-Jack beans silage or whole plant sorghum-Velvet bean (VB) silage from Lima-Orozco et al. (2014) were used to assess the integration of agronomic considerations in an overall evaluation including biomass production, nutritive value and conservation quality.
The metabolisable energy (ME) and the digestible CP at the small intestine (dCPSI)of whole plant sorghum silage supplemented with dry beans of Jack beans, whole plant sorghum-Jack beans silage and whole plant sorghum-Velvet bean were calculated from data reported byLima-Orozco et al.(2014)in both in vitro rumen degradability (12 h) and the in vitro small intestine digestibility as follows:
]]> ME= (ER+ESI)/0.62, where ER is the net energy from acetate (874 kJ/mol), propionate (1535 kJ/mol) and butyrate (2192 kJ/mol) produced in the rumen; ESI is the net energy calculated from digestible OM in the small intestine as 16.7 kJ/g OM and 0.62 is the net energy to ME ratio for cows at maintenance.dCPSI(g/kg DM)=MIN(dCPR)*0.75*0.85+dbpCPSl, where dCPR (g/kg DM) is the microbial protein produced based on the supply of effectively rumen degradable CP (g/kg DM);dMP(g/kg DM) is the amount of microbial protein calculated based on apparently rumen degradable organic matter (ARDOM) as 187.5 g CP/kg ARDOM (with ARDOM calculated from the net production of acetate, propionate and butyrateas 162*(acetate/2+propionate/2+butyrate)); MIN (dCPR) means that calculation of the microbial protein depends on whether the availability of rumen degradable protein (dCPR) or fermentable energy (dMP) is the limiting factor for microbial protein production (Tamminga et al. 1994); the factors 0.75 and 0.85 represent the amino acid contents of microbial protein and intestinal digestibility of microbial amino acids, respectively (Tamminga et al.1994); dbpCPSI is the intestinal digestible bypass CP. In the current trial, dCPR always exceeded dMP and hence, the microbial protein was determined from the energy released during fermentation.
Differences of theME and dCPSIbetween treatments (sorghum silage + dry beans of Jack beans and sorghum-Jack beans silage or sorghum-Velvet bean silage) were compared by a one way ANOVA by means of a non-parametricWilcoxon rank sum test performed with jmp (jmp 9.0.2 copyright (c) 2010 SAS Institute Inc.).
RESULTS AND DISCUSSION
JB showed higher forage and grain yield (table 1) as compared with VB (grain yield; 1.24 t DM/ha). Assessment of ensiling quality showed that, with a proportion of 50:50 of fresh whole sorghum plants and fresh whole JB plants, a sufficient feed quality for ruminants could be reached (Lima-Orozco et al. 2014). When pure sorghum silage is supplemented with stored dry grains form JB, 88g of sorghum silage is required per 100 g of FM (78 g on DM basis) to reach a similar CP content as for the combined sorghum-legume silage.To obtain the equivalent ME supply from combined whole plant sorghum-JB silage and sorghum-VB silage or pure sorghum silage supplemented with JB dry grains, 6 and 26 % more DM is required, respectively (table 1). More importantly, this corresponds to a demand of 1.4 to 2.5 times the surface required to co-culture sorghum-JB forage. When sorghum silage is supplemented with dry beans from JB, an equivalent dCPSI supply as from sorghum-JB silages requires 44% more feed. Moreover, the area required to produce sorghum and JB as monocultures is 2.90 times the surface required for sorghum-JB intercropping.To supply similar dCPSi from combined sorghum-VB silages 1.65 times more surface is required.
Given the world’s population growth, substantial increase of agriculture production while simultaneously decreasing its environmental footprint, is required. In their analysis for solutions to this dilemma Foley et al. (2011) indicated agriculture expansion should be halted and increasing food production should be reached by closing crop yield gaps on existing agricultural land. Hence, within this context, protein alternatives not only should be compared in terms of nutritive value but also the surface required for supply of comparable amounts of energy and digestible proteinshould be considered.
The grain and forage yield reached by JB in the current study is similar to what has been reported by Díaz (2000) and show the potential of this crop inruminant feeding systems as yields are considerably greater than those of other legumes e.g. VB as reported in this work (Table 1) or soybean in previous reports (Lima-Orozco et al. 2013).
A dCPSI supply equal to that from mixed sorghum-JB silage requires 22 t DM extra from sorghum-VB silages or 44 t DM extra from sorghum silage supplemented with dry bean form JB. Similarly, 8 t DM extra is needed from whole plant sorghum and soybean silages(Lima-Orozco et al. 2013).In addition, more hectares are needed to produce sorghum silage supplemented with dry beans with the extra cost of sorghum fertilization (60 kg N/ha). Additionally, this amount of sorghum silage supplemented with dry beans would supply a lower amount of ME. Grains from VB were not considered here as an alternative given their lower yield and a longer growing period (180-200 d)as compared with JB or soybean for which only 120-140 d or 90-120 d (Díaz 2000) are needed, respectively. These harvesting times are similar to previous reports and are influenced among others by the legume species/cultivar and harvesting season (Díaz 2000; Lima-Orozco et al. 2013).
It was concluded that the ME content and dCPSIof the sorghum-JB silages are1.26 or 1.44 times higher than sorghum-JB silage or for pure sorghum silage supplemented with dry beans from JB. Moreover, a much larger surface is required for the sorghum silage and dry JB grains alternative. Hence, combined sorghum-JB silage seemed the best alternative studied here in terms of DM yield, dCPSI and MEsupply.
]]>ACKNOWLEDGEMENTS
The authors would like to thank to VLIR-USO for a short research grant to R. Lima Orozco and to the commission of Scientific Research of the Faculty of Bioscience Engineering of UGent for travel grant of Inge Van Daele, to the staff of the Laboratory for Animal Nutrition and Animal Product Quality of UGent and to the staff from the Experimental Stations in CIAP of UCLVfor the technical assistance during this research.
REFERENCES
Díaz, M. F. 2003. ‘‘Producción y caracterización de forrajes y granos de leguminosas temporales para la alimentación animal’’. Cuban Journal of Agricultural Science, 37 (1), pp. 65–71, ISSN: 2079-3480.
Foley, J. A., Ramankutty, N., Brauman, K. A., Cassidy, E. S., Gerber, J. S., Johnston, M., Mueller, N. D., O’Connell, C., Ray, D. K., West, P. C., Balzer, C., Bennett, E. M., Carpenter, S. R., Hill, J., Monfreda, C., Polasky, S., Rockström, J., Sheehan, J., Siebert, S., Tilman, D. & Zaks, D. P. M. 2011. ‘‘Solutions for a cultivated planet’’. Nature, 478 (7369), pp. 337–342, ISSN: 0028-0836, DOI: 10.1038/nature10452.
Lima-Orozco, R., Castro, A. A. & Fievez, V. 2013. ‘‘Ensiled sorghum and soybean as ruminant feed in the tropics, with emphasis on Cuba’’. Grass and Forage Science, 68 (1), pp. 20–32, ISSN: 1365-2494, DOI: 10.1111/j.1365-2494.2012.00890.x.
Lima-Orozco, R., Van Daele, I., Álvarez, H. U. & Fievez, V. 2014. ‘‘Combined conservation of jack bean and velvet bean with sorghum: evaluation of lab-scale silages and in vitro assessment of their nutritive value’’. The Journal of Agricultural Science, 152 (06), pp. 967–980, ISSN: 1469-5146, DOI: 10.1017/S0021859614000148.
Ojeda, F. 2000. ‘‘Harvesting and ensiling techniques’’. In: Silage Making in the Tropics with Particular Emphasis on Smallholders, Rome: FAO, ISBN: 978-92-5-104500-8.
]]>SAS Institute. 2010. Statistical Analysis Software SAS/STAT®. version 9.0.2, Cary, N.C., USA: SAS Institute Inc, ISBN: 978-1-60764-599-3, Available: <http://www.sas.com/en_us/software/analytics/stat.html#> .
Received: November 25, 2015
Accepted: March 8, 2016
R. Lima-Orozco, Universidad Central “Marta Abreu” de Las Villas (UCLV), Department of Veterinary Medicine and Zootechny, Carretera a Camajuaní km 6 ½, 54830 Santa Clara, Cuba. Email: raciello@uclv.edu.cu
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