Effect of pelleting on nutritive quality of forage legumes

D K Oyaniran, V O A Ojo, R Y Aderinboye¹, B A Bakare and J A Olanite

Department of Pasture and Range Management, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
oyanirandammy4real@yahoo.com
¹ Department of Animal Nutrition, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria

Abstract

The chemical composition, anti-nutritional factors and in vitro gas production of fresh (unpelleted) and pelleted forms of three herbaceous legumes were determined. The three legumes were sown at spacing of 0.5 m² and harvested 10 cm above ground level at 12 weeks after sowing at early dry season. Harvested samples were divided into two with one part left as fresh (unpelleted) and the other processed into pellets. The experiment was arranged as 2x3 factorial. The factors were two different forms of processing (unpelleted and pelleted) and three herbaceous legumes ( Lablab purpureus, Calopogonium mucunoides and Mucuna pruriens). The crude protein content for the forms of processing of legumes were similar. Unpelleted form of the legumes had higher neutral detergent fibre than the pelleted form. Higher values of calcium and phosphorus were in pelleted legumes than in the unpelleted. Highest crude protein content (123 g kg^-1) was in L. purpureus while highest value of fibre fractions were in C. mucunoides than other legumes. Higher tannin, oxalate and saponin contents were in M. pruriens. Higher gas and methane were produced at 24 hours of incubation in pelleted feeds than unpelleted. In conclusion, processing of the legumes into pellets reduced the fibre fraction contents, anti-nutritional factors and increased gas produced while higher crude protein content, lower fibre fraction and higher gas produced were recorded for L. purpureus over other legumes investigated.

Key words: anti-nutritional, chemical composition, in vitro gas production

Introduction

Forages are considered as the cheapest major nutritional component in the diets of ruminants particularly in the rural and suburban area of the tropics (Akinsoyinu and Onwuka 1998). The availability of forages in quantity and quality can be adequate for optimum livestock production to ensure a high level of productivity. Forages are classified into grasses; the main source of energy and legumes which are the main source of protein. Legumes are rich in protein and they have the potential to reduce the cost of feeding animals. The use of forage legumes in livestock production systems has increased in the tropics in recent years. Herbaceous forage legumes have been identified as potential supplements for ruminants (Ajayi et al 2008). However, seasonal fluctuations results in their low quality and unavailability, which poses a threat to livestock survival. Farmers are faced with the challenges of sourcing adequate feeds for their stock during dry seasons. During this period, the nutritive value of the forages decline while animals are faced with reduced feed intake and loss of weight. Legumes such as Lablab purpureus, Calopogonium mucunoides and Mucuna pruriens can be conserved as silage, hay and pellets to meet the nutritional needs of animals when there is low availability (Amole et al., 2013). The major constraint in large scale hay production in the tropics is unreliable weather conditions and poor herbage quality for most of the year (Crowder and Chheda 1982). Conservation of legumes as silage is not extensively practiced worldwide because of their high buffering capacity and low concentration of fermentable carbohydrates which limits the quality of their silage (Tauqir et al 2009). Conserving of the forage legumes into pellets form reduces the fibre contents and bind the nutrients together which will further improve the intake and digestibility of the animals. The objectives is therefore to determine the chemical composition, anti-nutritional and in vitro gas production of three legumes (Lablab purpureus, Calopogonium mucunoides and Mucuna pruriens) in pelleted and unpelleted forms.

Materials and methods

The field experiment was carried out at the Directorate of University Farms while the chemical analyses were carried out at the laboratory of the Department of Pasture and Range Management, College of Animal Science and Livestock Production both at Federal University of Agriculture, Abeokuta, Ogun State, Nigeria. The location lies within latitude 7^o 10’ N, longitude 3^o 2’ E, and altitude 76 mm in the derived savannah zone of South-Western Nigeria. It has an average annual rainfall of 1037 mm and temperature of about 34.7^oC and an average relative humidity of 82%. The three legumes were sown at spacing of 0.5 m² and harvested 10 cm above ground level at 12 weeks after sowing at early dry season. Harvested samples were divided into two parts. One part was retained in the fresh form while the second part was processed into pellets. Samples of fresh leaves (Unpelleted) of each harvested legume were weighed and oven dried at 65 ^oC until constant weight. The second portion of the legumes were dried, milled and pelletized using a 6 mm die size to produce pelleted forage of average length of 40 mm. Cassava flour was used as binder (proportion of 1 kg of cassava flour to 100 kg of the milled sample) with addition of water to moisten. The pellets were warm and moist, when they came out of the mill. They were then cooled down to harden up so as to hold their form.

Subsamples of the pellets were weighed and oven dried at 65 ^oC to a constant weight. The pelleted and unpelleted legumes were milled using hammer mill to pass through 1mm sieve for chemical analyses. The dry matter contents, crude protein, ether extract and ash were determined according to AOAC (2000). Fibre fractions analysis for neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) were done according to the procedure of Van Soest et al (1991). The concentration of phosphorus was estimated with a flame photometer after wet digestion in nitric acid and per chloric acid. Concentration of calcium were determined with atomic absorption spectrophotometer (Fritz and Schenk 1979). Tannin content was determined using the Vanillin-HCl method as described by Price and Betler (1977). Phytate content was determined by the photometric method of Latta and Eskin (1980). Oxalate determination was carried out using the methods of Munro (2000). Saponin content was determined according to the method of Obdoni and Ochuko (2001).

The in vitro gas production was determined following the procedure of Meneke and Steingass (1988). Rumen fluid (inoculum) was collected inside a pre-warmed flask from three cattle using the method of Babayemi and Bamikole (2006). The inoculum was filtered through three layers of cheese cloth and mixed with sodium and ammonia bicarbonate buffer (35 g NaHCO ₃ plus 4 g NH₄HCO₃ per litre) at a ratio of 1:2 (v/v) to prevent lowering the pH of the rumen fluid which could result in decreased activities of the microbes. Thirty millimeters of the buffered inoculum was added to 100 ml glass syringes containing 0.2 mg of milled samples and were placed in an incubator at 40 ^oC and the gas released was read directly on the syringe. Gas production was recorded at 3, 6, 9, 12, 15, 18, 21 and 24 hours of incubation. Five (5) ml syringe capacity containing 4 ml NaOH was introduced into the syringes at the end of the incubation so as to determine methane production. Sodium hydroxide was added to absorb CO₂ produced during the experiment and the remaining was recorded as methane according to Fievez et al (2005). All data obtained in this study were subjected to two way analysis of variance (ANOVA) and significant difference between means were separated using Duncan multiple range test (SAS, 2001).

Results and discussion

Table 1 shows the effect of pelleted and unpelleted legumes on chemical composition (g kg^-1 DM). The dry matter content of C. mucunoides was lower than the values of 88.7 % reported by Taiwo et al (2009) and 89.84 % by Obua et al (2012). The crude protein content of L. purpureus in this study fell within the range of 11-19 % for L. purpureus harvested at 45, 60 and 75 days after sowing (Mahala et al 2012) but lower than the value of 24.15 % reported by Obua et al (2012) for C. mucunoides which was harvested in South East, Nigeria. Lowest crude protein content in M. puriens might be due to high tannin content in it which has the ability to bind protein (McSweeney et al 2001). However, the crude protein content of legumes recorded in this study was higher than the minimum recommended range of 7.0 - 8.0 % for efficient functioning of rumen micro organisms (Van Soest 1994). The ash content represent the mineral level in a feed, such as phosphorus, calcium and potassium (Verma 2006). The ash content in L. purpureus obtained in this study was higher than the values of 6.66 and 7.18 % reported by Nworgu and Ajayi (2005) for L. purpureus harvested at 12 WAS in 2001 and 2002. Meanwhile, Obua et al (2012) recorded a higher value of 9.79 % for C. mucunoides harvested in South East, Nigeria. The differences observed in this study and by other authors could be due to the age of plants at harvest, geographical location, processing methods adopted, season and status of the soil.

The neutral detergent fibre, acid detergent fibre and acid detergent lignin contents in the pelleted legumes were lower than that of unpelleted legumes. This could be due to the effect of grinding and pelleting process which reduced the particle size and fibre contents in the plants. Allen (1996) stated that reduction in forage particle size greatly influences the effectiveness of fibre. The NDF values obtained for the legumes in this study were lower than the range of 60-65 % suggested as the critical limit above which efficiency of utilization of tropical forages by ruminants would be impaired (Muia 2000). The NDF content of L. purpureus was higher than value of 41.1 % for NDF content in L. purpureus harvested at 45 days after planting (Mahala et al 2012). This could be due to age at harvest of the plant and this is in line with the findings of Minson (1990) who reported that as the plants mature, the fibre content increases which will lead to reduction of feed intake of the animals. McDonald et al (1991) reported that the higher the ADF, the less digestible the feed and the less energy it contains. From this study, the legume pelleted form will digest better and have higher energy contents because of the lower ADF content compared to unpelleted.

The presence of mineral elements in animal feed is vital for the metabolic processes of the animals (Akinsoyinu and Onwuka 1988). Calcium concentrations in different forages as well as different forms investigated in this study were higher than the recommended range (0.20-0.26 g /100g) for maintenance of growing and lactating sheep (Reuter and Robinson 1997). Lower calcium content observed in unpelleted legume compared to pelleted could be due to higher content of oxalate in unpelleted legume which have been reported to have higher effect of binding calcium to form calcium oxalate (Smitha et al 2013).

The anti-nutritional factors in forage legumes as influenced by forage species and pelleting are presented in table 2. Higher content of tannin, oxalate and phytate were recorded for unpelleted above pelleted legumes. Anti-nutritional factors are compounds which reduces the nutrient utilization and food intake of plants used as feed for human or animal. The reason for decrease in tannin contents in pelleted legumes than in unpelleted could be as a result of the processing method employed. In the processing of leaves to pellets, heat was generated and according to Wiryawan (1997), the application of heat in processing methods decrease the anti-nutritional factors. Babayemi (2009) also reported a decrease in the secondary metabolites of wild cocoyam when soaked in hot water. Tannin contents for L. purpureus and pelleted legumes were moderate and suggest an advantage of by-pass protein for ruminants (Barry and McNabb, 1999).

Table 3 reveals the effects of legume species and their processing forms on the in vitro gas and methane production. The gas production of the legumes increased with the duration time due to longer time allowed for digestion of legumes in the rumen fluid by the micro organism. A high gas production indicates greater fermentation to support rapid rumen microbial growth (Gemeda and Hassen 2015). The gas production in pelleted and unpelleted legumes were similar in the first 21 hrs of incubation. However, it was higher in the pelleted legumes at 24 hrs of incubation than unpelleted (Table 3; Figure 1). This might be due to higher fibre contents that were higher in unpelleted legumes than the pelleted. Tannins contents which are phenolic compounds have significant effect on methane and rumen function, depending on plants, type and level of tannin (Mueller-Harvey, 2006, Patra and Saxena 2011). It was observed that the methane gas produced in this study was higher in pelleted legumes than unpelleted. However the tannin content in the pellets was lower than 20-50 g kg^-1 which will have no negative effect on the micro organism in the rumen (Diagayete and Hugg 1981). Lowest methane was produced in C. mucunoides which had the lowest anti-nutritional factors. It was reported that cattle consuming high fibre diets lose 6% of gross dietary energy compared to those on low fibre diets that generally lose 3-3.5 % of dietary gross energy as methane (Johnson and Johnson 1995).

Figure 1. In-vitro gas production from pelleted and unpelleted tropical forage legumes

Figure 2. Methane gas production from pelleted and unpelleted forage legumes

Conclusions

• Processing of the legumes into pellets reduced the fibre fraction content and anti-nutritional factors and increased gas production.
  
  
• Higher crude protein content, lower fibre fraction and higher gas production was recorded for L. purpureus over other legumes investigated .

Acknowledgments

The authors wish to acknowledge and appreciate the financial support from The Tertiary Education Trust Fund, through Directorate of Grants Management, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria for project titled "Legume based pellet as dry season feed resources for ruminant animals" of which this research was part.

References

Akinsoyinu A O and Onwuka C F I 1988 Mineral constituents of some browse plants used in ruminant feeding in southern Nigeria. Nigerian Journal of Animal Production 15: 57-62

Ajayi F T, Babyemi O J and Taiwo A A 2008 Effect of supplementation of Panicum maximum with four herbaceous forage legumes on performance, nutrient digestibility and nitrogen balance in West African dwarf goats. Journal of Animal Science 79(6):673-679

Allen 1996 Physical constraints on voluntary intake of forages by ruminant. Journal of Animal Science 74:3063-3075

AOAC 2000 Official methods of Analysis, Association of Official Analytical chemists, Washington D.C. 17^th edition

Babayemi O J and Bamikole M A 2006 Effects of Tephrosia candida DC Leaf and its mixtures with Guinea grass on the in vitro fermentation changes as feed for ruminants in Nigeria. Pakistan Journal of Nutrition 5 (1): 14-18

Babayemi O J and Bamikole M A 2009 Nutritive value and in vitro gas production of African wild cocoyam (Colocasia esculentum). African Journal of Food Agriculture Nutrition and Development 9(1):1584-5374

Barry T N and McNabb W C 1999 The implications of condensed tannins on the nutritive value of temperate forages fed to ruminants. British Journal of Nutrition 81 (4): 263-272

Crowder L V and Chedda H R 1982 Tropical grassland husbandry, Longman Inc. New York, pp 315

Diagayete M and Hugg W 1981 Tannin contents of African pasture plants: Effects on analytical data and in vitro digestibility. Animal Research and Development 15: 79-90.

Fievez V, Babayemi O J and Demeyer D 2005 Estimation of direct and indirect gas production in syringes: a tool to estimate short chain fatty acid production requiring minimal laboratory facilities. Animal Feed Science and Technology 123-124: 197-21

Fritz J S and Schenk G H 1979 Quantitative Analytical Chemistry, 4^th edition. Allyn and Bacon, Boston, pp 661

Gemeda B S and Hassen A 2015 Effect of tannin and species variation on in vitro digestibility, gas and methane production of tropical browse plants Asian-Australasian Journal of Animal Science 28(2):188-199

Johnson K A and Johnson D E 1995 Methane emissions from cattle Journal of American Society of Agronomy 73:2483-2492

Latta M and Eskin 1980 A simple and rapid colorimetric method for phytate determination Journal of Agriculture and Food Chemistry, 28: 1313-1315

Mahala A G, Amasiab S O, Monera A, Yousif and Elsadig A 2012 Effect of plant age on dry matter yield and nutritive value of some leguminous plants (Cyamopsis tetragonoloba, Lablab purpureus and Clitoria ternatea). International Research Journal of Agricultural and Soil Science 2: 502-508

McDonald P, Henderson A R and Heron S J E 1991 The biochemistry of silage. Chalcombe Publications, London

McDowell L R 1997 Minerals for Grazing Ruminants in Tropical Regions. Extension Bulletin, Animal Science Department, Centre for Tropical Agriculture, University of Florida. 81

McSweeney C S, Palmer B, McNeill D M and Krause D O 2001 Microbial interactions with tannins: nutritional consequences for ruminants. Animal Feed Science and Technology 91: 83–93

Menke K H and Steingass H 1988 Estimation of the Energetic Fed Value from Chemical Analysis and in vitro Gas Production Using Rumen Fluid. Animal Research Development 28: 7-55

Minson D J 1990 Forage in Ruminant Nutrition. Academic Press, New York, USA

Mueller-Harvey I 2006 Unraveling the conundrum of tannins in animal nutrition and health. Journal Science of Food Agriculture 86:2010-2037

Muia J M K 2000 Use of Naiper grass to improve small holder milk production in Kenya. Ph.D Thesis. Wageningen Agricultural University. The Netherlands

Munro A B 2000 Oxalate in Nigerian vegetables. West African Journal of Biological Applied Chemistry 12(1): 14 18

Nworgu F C and Ajayi F T 2005 Biomass, dry matter yield, proximate and mineral composition of forage legumes grown as early dry season feeds. Livestock Research for Rural Development, 17(11):http://www.lrrd. org/lrrd17/11/nwor17121. htm

Obdoni B and Ochuko P 2001 Phytochemical studies and comparative efficacy of the crude extracts of some homostatic plants in Edo and Delta States of Nigeria. Global Journal of Pure and Applied Science 8: 203–208

Obua B E, Okocha C N and Nwaoha L E 2012 Proximate composition and anti-nutritional factors of some forage species used in feeding rabbits in Umudike, humid South Eastern Nigeria. Journal of Agricultural and Rural Development 15 (3):1275-1286

Orden E A, Serra A B, Serra S D, Aganon C P, Cruz E M, Cruz L C and Fujihara T 1999 Mineral concentration in blood of grazing goat and some forage in Lahar-Laden Area of central Luzon, philippines. Asian Australian Journal of Animal Science 12(3) : 422-428

Patra A K, Saxena J 2011 Exploitation of dietary tannins to improve rumen metabolism and ruminant nutrition. Journal Science of Food Agriculture 91:24-37

Price M L and Butler L G 1977 Rapid visual estimation and spectrophotometric determination of tannin content of sorghum grain. Journal of Agriculture and Food Chemistry, 25: 1268–1273

Reuter D J and Robinson J B 1997 Plant Analysis. An Interpretation Manual (2^nd edition) CSIRO Publishing: Melbourne.

SAS 2001 Statistical Analysis System. User's Guide: Statistics Version 8.2. SAS Institute, NC, USA.

Smitha P A, Alagundagi S C and Salakinko S R 2013 The anti-nutritional factors in forages. Current Biotica 6(4): 516-526

Tauqir N A, Sarwar M, Jabbar M A and Mahmood S 2009 Nutritive value of jumbo grass silage in lactating nili-ravi buffaloes. Pakistan Veterinary Journal 29(1): 5-10

Taiwo B B A, Adekunmisi A A and Adeyemi A A 2009 Browse plants of Egbado north rangeland: Distribution and chemical composition. Proceedings of the 14^th Annual Conference of Animal Science Association of Nigeria, September 14^th-17^th, 2009, Ogbomoso, Nigeria. Pp. 603-605

Van Soest P J 1994 Nutritional Ecology of the Ruminant (2^nd Edition). Cornell University Press, Ithaca, New York, ISBN-13: 9780801427725, pp 476

Van Soest P J, Robertson J B and Lewis B A 1991 Methods for dietary fibre, neutral detergent fibre and non-starch polysaccharides in relation to animal nutrition. Journal Dairy Science 74 (10): 3583- 3597

Verma D N 2006 A Textbook of Animal Nutrition Kalyani Publishers New Delhi-110 002: 126-132

Wiryawan K G 1997 Grain legumes for poultry. Ph.D Thesis. The university of Queensland, Australia

Received 19 December 2017; Accepted 7 March 2018; Published 1 April 2018

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