The biomass of trees and legumes plants has played an important role in ruminants feeding in recent years. Legumes forage plants have proven to be a favorable option to complement ruminant feeding. However, there are other plants with potential for foliage production, which have nutritional value comparable to legumes, such as Moringa oleifera (Gutiérrez et al. 2015Gutiérrez, D., Borjas, E., Rodríguez, R., Rodríguez, Z., Stuart, R. & Sarduy, L. 2015. Evaluación de la composición química y degradabilidad ruminal in situ de ensilaje mixto con Pennisetum purpureum cv. Cuba CT-169: Moringa oleifera. Avances en Investigación Agropecuaria, 19(3): 7-16, ISSN: 2638-1716. http://www.redalyc.org/articulo.oa?id=83743886002. ). Other factors, such as environmental factors, influence the bromatological composition and nutritional value of plants, such as soil and climate conditions and different varieties, although there is still a lack of information to determine the nutritional value of different species.
Studies of ruminal degradability infer the quality of nutrients in food. Currently, the in sacco method has been the most effective method to study food degradation within the rumen (Elizondo-Salazar and Monge-Rojas 2020Elizondo-Salazar, J.A. & Monge-Rojas, C.R. 2020. Fistulación en bovinos y uso de la técnica de degradabilidad ruminal para análisis de alimentos. Nutrición Animal Tropical, 14(2): 209-229, ISSN: 2215-3527. http://dx.doi.org/10.15517/nat.v14i2.45167. and Meza-Bone et al. 2022Meza-Bone, G., Meza-Bone, C., Avellaneda-Cevallo, J., Godoy-Montiel, L., Barros-Rodríguez, M. & Jines-Fernández, F. 2022. In vitro ruminal degradation of Tithonia diversifolia. Agronomía Mesoamericana, 33(1): 43206, ISSN: 2215-3608. https://doi.org/10.15517/am.v33i1.43206. ). The nylon bag technique for measuring the ruminal degradability of food samples remains highly useful in evaluating plant species with potential for ruminant feeding. The objective of this study was to determine the in situ ruminal degradability of dry matter (DM) from the plants Erythrina variegata (Erythrina), Leucaena leucocephala (Leucaena), Moringa oleifera (Moringa) and Neonotonia Wightii (Glycine).
The study was conducted at the Dr. Juan Tomás Roig Experimental Station of the Bioplant Center, belonging to Máximo Gómez Báez University of Ciego de Ávila.
Collection and processing of samples: The different foliage samples were collected in areas of Ciego de Ávila municipality, in livestock farms and at the University of Ciego de Ávila.
Composite samples of foliage from four protein plants were random collected: Erythrina, Leucaena, Moringa and Glycine. In each case, leaf-petiole samples were taken. They were dried at 65°C in a forced-air oven for 48 h.
The milling of all samples was performed to obtain particle sizes between 2.5 and 3 mm for ruminal degradability analyses and between 0.8-1 mm for chemical DM analyses. In all cases, a hammer mill with its corresponding sieves was used and the processed material was properly preserved until use.
Animal management and diets: Samples from two male Pelibuey sheep, with live weight of 36 kg and cannulated in the dorsal rumen sac were taken. The animals grazed in an area dominated by the creeping legume Teramnus labialis and had free access to water and common salt.
Procedure for separating soluble and insoluble fractions of foliage: Between 1-2 g of DM sample was placed in a beaker with 150 mL of distilled water at room temperature (20-25 °C) for 105 min, with intermittent stirring. The solution was filtered through a Whatman No. 1 filter paper (15 cm diameter) and the residue was washed with distilled water until approximately 500 mL of the filtrate was collected. The filter paper, containing the insoluble residues, was placed in an oven at 60 °C for 48 h. The paper with the dry residue was quickly transferred to a previously weighed plastic bag and was hermetically sealed. The bag was weighed after one hour and washing losses were calculated by weight difference.
In situ ruminal degradability. The determination of the DM ruminal degradability of the evaluated plant materials was carried out according to the nylon bag procedure or in situ, described by Mehrez and Ørskov (1977)Mehrez, A.Z. & Ørskov, E.R. 1977. A study of artificial fibre bag technique for determining the dig estibility of feeds in the rumen. The Journal of Agricultural Science, 88(3): 645-650, ISSN: 1469-5146. https://doi.org/10.1017/S0021859600037321. . A total of 5 g of sample of each collected plant material (Erythrina, Leucaena, Moringa and Glycine) were weighed in duplicate for each incubation time and animal. For this purpose, Ankom® Dacron/polyester nylon bags (ANKOM Technology) were used, with a pore size of 50±10 µm and internal dimensions of 10 x 20 cm, previously weighed and properly identified.
The bags were closed and immersed for 30 seconds in clean water, before their incubation in the rumen, in order to prehydrate them and generate the correction factor for particle escape at 0 h. They were introduced sequentially into the ventral compartment of the rumen of the animals, cannulated at 0, 8, 16, 24, 36, 48 and 72 h, and then they were simultaneously removed. For this purpose, a polyester bag attached to a 50.0 cm long nylon rope was used.
Then, each bag was manually washed with running water until the water ran clear. They were placed on aluminum trays and dried for 48 h at a temperature of 60 °C in a forced-ventilation oven. Later, they were transferred to a desiccator for 30 min and weighed on a precision balance to determine the DM disappearance. The difference between the initial weight of the sample placed in the nylon bags and the weight of the residue after ruminal incubation was used to determine the DM degraded in the rumen.
The DM was determined according to AOAC (1995)AOAC, 1995. Official Methods of Analysis. 16th Ed. Assoc. Off. Agric. Chem. Washington, D.C.. Residual DM contents were determined in triplicate by drying 2 g of sample at 105 °C for 24 h.
Data processing and statistical analysis: To determine the degradative characteristics, the exponential model proposed by Ørskov and Mc Donald (1979)Ørskov, E.R. & McDonald, I. 1979. The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage. The Journal of Agricultural Science, 92(2): 499-503, ISSN: 0021-8596. https://doi.org/10.1017/S0021859600063048. was used. It was assumed that the DM degradation curve (DMD) over time follows a first-order kinetic process described as follows:
where:
P: Ruminal degradation. Is the ruminal degradation of the indicator evaluated over the time (t) it remains in the rumen
a: Intersection of the degradation curve at time zero. Represents the rapidly degrading component
b: Potential degradability of the component at time t
e: Base of natural logarithms (2.71828)
c: Constant rate of degradation of fraction (b)
a + b: Total degradability of the component
t: Incubation time
A: Rapidly soluble fraction. Obtained by incubating the sample in a water bath at 39 °C for 30 minutes
To determine the effective ruminal degradability (ED), the McDonald model (1981)McDonald, I. 1981. A revised model for the estimation of protein degradability in the rumen. The Journal of Agricultural Science, 96(1): 251-252, ISSN: 1469-5146. https://doi.org/10.1017/S0021859600032081. was used.
where:
ED: Effective ruminal degradability in situ
k: Fractional ruminal passage rate. k = 0.02 is assumed
B: Insoluble but potentially degradable fraction. B=(a+b) -A (Ørskov 2002Ørskov, E.R. 2002. Trails and trails in Livestock Research. Abeerden. Garamond. pp.204.)
c: Degradation rate of the fraction
For the mathematical estimation of the DM degradation kinetics of each of the materials, the NEWAY EXCEL program (Chen 2000Chen, X. B. 2000. NEWAY: Curve fitting programme software for Orskov’s model (DOS version). International Feed Resources Unit, Macaulay Land Use Research Institute, Aberdeen, Scotland. ) was used.
The parameters of ruminal kinetics and DM degradability of the plant materials evaluated (table 1) show that the effective degradability of DM maintained an increasing trend in the following order: Glycine, Leucaena, Erythrina and Moringa. The creeping legume Glycine had values below 50 %, while the rest of the plant materials were between 53.81 and 59.35 %, with the highest value for Moringa.
| Parameters | Moringa | Erythrina | Leucaena | Glycine |
|---|---|---|---|---|
| A (%) | 37.95 | 35.97 | 34.8 | 30.10 |
| B (%) | 52.55 | 52.53 | 51.78 | 45.15 |
| A+B (%) | 90.50 | 88.50 | 86.58 | 75.25 |
| c ( Fraction h-1) | 0.081 | 0.075 | 0.072 | 0.063 |
| R2 | 0.99 | 0.97 | 0.99 | 0.98 |
| ED (%) k: 0.02 | 59.35 | 56.00 | 53.81 | 45.35 |
A: soluble fraction, B: insoluble but potentially degradable fraction, A+B: potential degradability, c: degradation rate of fraction B, R2: coefficient of determination belonging to the model, ED: effective ruminal degradability.
The model used in the analysis showed high coefficients of determination (R2) for each of the plant materials. The values of the soluble fraction (A) also showed a tendency to increase in the same order as the mentioned plant materials. The potentially degradable fraction (B) presented similar values in Moringa, Erythrina and Leucaena, while in Glycine it was less than 50% of the DM. Likewise, the potential degradability (A+B) showed the same trend in the plant materials as the soluble fraction (A). Moringa highlighted with 90.5% potential degradability and Glycine with the lowest value.
The evolution of the disappearance of DM after in situ ruminal incubation (figure 1) showed an increase as the incubation time increased for plant materials. Moringa showed higher ruminal degradability values than the rest of the plants at each hour of evaluation. The trend of ruminal degradability of plant materials was increasing in the following order: Glycine, Leucaena, Erythrina and Moringa. For the latter plant, a ruminal degradability of more than 80 % was obtained at 72 h, while Glycine showed a value less than 60 %.
Degradation kinetics showed an increase in the disappearance of DM with the incubation time in the rumen. Likewise, the fit of the in situ ruminal degradability data to the proposed model, P = a + b (1 - e-ct) showed R2 equal to or higher than 97.0 for the studied plants. This shows a correct fit of the degradation values to the model (table 1). The above explains the degradative performance of these protein plant materials and shows that the structural compounds of the cell wall did not prevent the action of ruminal cellulolytic microorganisms (Gutiérrez et al. 2015Gutiérrez, D., Borjas, E., Rodríguez, R., Rodríguez, Z., Stuart, R. & Sarduy, L. 2015. Evaluación de la composición química y degradabilidad ruminal in situ de ensilaje mixto con Pennisetum purpureum cv. Cuba CT-169: Moringa oleifera. Avances en Investigación Agropecuaria, 19(3): 7-16, ISSN: 2638-1716. http://www.redalyc.org/articulo.oa?id=83743886002. ).
La O et al. (2018)La O, O., González, H., Vázquez, M.C., Hernández, J., Estrada, A. & Ledea, J.L. 2018. Nutritional characterization of Gliricidia sepium in a saline and high drought ecosystem of the Cauto river basin, Cuba. Cuban Journal of Agricultural Science, 52(3): 347-356, ISSN: 2079-3480. https://cjascience.com/index.php/CJAS/article/view8256. with Gliricidia sepium forage, from a saline and high drought ecosystem, found values of effective ruminal degradability of DM between 63.1 and 67.6 % for different ruminal turnover constants. Likewise, the values of the soluble fraction A) 40.7 % and insoluble fraction B) 36.76 % differed from those found in the evaluated plants (table 1). However, the A+B fraction of Moringa, Erythrina and Leucaena was superior to Gliricidia sepium, according to La O et al. (2018)La O, O., González, H., Vázquez, M.C., Hernández, J., Estrada, A. & Ledea, J.L. 2018. Nutritional characterization of Gliricidia sepium in a saline and high drought ecosystem of the Cauto river basin, Cuba. Cuban Journal of Agricultural Science, 52(3): 347-356, ISSN: 2079-3480. https://cjascience.com/index.php/CJAS/article/view8256. . Apparently, these differences can be attributed to the different proportions of soluble carbohydrates and the bromatological composition, as well as other factors related to edaphoclimatic conditions.
Valenciaga et al. (2018)Valenciaga, D., López, J.R., Galindo, J., Ruiz, T. & Monteagudo, F. 2018. Cinética de degradación ruminal de materiales vegetales de Tithonia diversifolia recolectados en la región oriental de Cuba. Livestock Research for Rural Development, 30(11): 186, ISSN: 0121-3784. http://www.lrrd.org/lrrd30/11/daiky30186.html. found different results in the degradability parameters of plant materials of Tithonia diversifolia, with lower values in the “a” fraction and higher values in the “b” fraction, compared with the evaluated plants (table 1). The ruminal degradability results of the protein plants in this study may have been related to their chemical composition (soluble carbohydrate content), which favored higher degradability of the Moringa dry matter at 72 h. The ruminal fermentation of these plants could promote greater availability of compounds such as ammonia, amino acids, peptides and branched short-chain fatty acids, which favors the synchronization of nitrogen and energy for the microorganisms of the rumen (Valenciaga et al. 2018Valenciaga, D., López, J.R., Galindo, J., Ruiz, T. & Monteagudo, F. 2018. Cinética de degradación ruminal de materiales vegetales de Tithonia diversifolia recolectados en la región oriental de Cuba. Livestock Research for Rural Development, 30(11): 186, ISSN: 0121-3784. http://www.lrrd.org/lrrd30/11/daiky30186.html. ). Gutiérrez et al. (2024)Gutiérrez, F., Sacido, M. & Feldman, S. 2024. Efecto sinérgico de las mezclas de raigrás perenne con trébol sobre la degradabilidad ruminal. Nutrición Animal Tropical, 18(2): 56-80, ISSN: 2215-3527. https://doi.org/10.15517/nat.v18i2.61798. confirm the benefits in ruminal degradability when mixing ryegrass (Lolium perenne) and two species of clovers (Trifolium repens and T. pretense). These authors found that the mixture with 70 % ryegrass and 30 % clover had a potential degradability (AB) between 90 and 96 %, results similar to the potential degradability of Moringa in this study.
The results of effective DM degradability (table 1) differ from most tropical grasses, which have values lower than 40 % (Ascencio-Rojas et al. 2019Ascencio-Rojas, L., Valles-de la Mora, B., Castillo-Gallegos, E. & Ibrahim, M. 2019. In situ ruminal degradation and effective degradation of foliage from six tree species during dry and rainy seasons in Veracruz, Mexico. Agroforestry Systems, 93: 123-133, ISSN: 1572-9680. https://doi.org/10.1007/s10457-018-0184-z. ). In this sense, better environmental conditions and ruminal degradability of forages can be achieved when shrub plants with higher protein levels than grass forages are included (Meza-Bone et al. 2022Meza-Bone, G., Meza-Bone, C., Avellaneda-Cevallo, J., Godoy-Montiel, L., Barros-Rodríguez, M. & Jines-Fernández, F. 2022. In vitro ruminal degradation of Tithonia diversifolia. Agronomía Mesoamericana, 33(1): 43206, ISSN: 2215-3608. https://doi.org/10.15517/am.v33i1.43206. ). Other authors determined higher DM degradability when the protein level was increased with the incorporation of legume fruits (Sosa-Pérez et al. 2023Sosa-Pérez, G., López-Ortiz, S., Pérez-Hernández, P., Vaquera-Huerta, H., Galván, M.M. & Gallegos-Sánchez, J. 2023. Degradability of the dry matter and crude protein of fruits of Chloroleucon manguense and Acacia cochliacantha in sheep. Pesquisa Agropecuária Brasileira, 58: e03026, ISSN: 1678-3921. https://doi.org/10.1590/S1678-3921.pab2023. ).
The obtained results are related to the chemical composition of the studied plants. The protein content can be considered to be in a higher range, in relation to forage grasses used for ruminants feeding. Furthermore, with high levels of soluble carbohydrates, which indicates a possible advantage of its use in ruminants, since with the amount of non-structural carbohydrates, a more efficient use of the degradable protein in the rumen is expected (Valenciaga et al. 2018Valenciaga, D., López, J.R., Galindo, J., Ruiz, T. & Monteagudo, F. 2018. Cinética de degradación ruminal de materiales vegetales de Tithonia diversifolia recolectados en la región oriental de Cuba. Livestock Research for Rural Development, 30(11): 186, ISSN: 0121-3784. http://www.lrrd.org/lrrd30/11/daiky30186.html. ).
The results of the ruminal degradation kinetics (figure 1) agree with other studies in non-legumes plants, such as those of Ascencio-Rojas et al. (2019)Ascencio-Rojas, L., Valles-de la Mora, B., Castillo-Gallegos, E. & Ibrahim, M. 2019. In situ ruminal degradation and effective degradation of foliage from six tree species during dry and rainy seasons in Veracruz, Mexico. Agroforestry Systems, 93: 123-133, ISSN: 1572-9680. https://doi.org/10.1007/s10457-018-0184-z. , who obtained 77 % degradation for Moringa oleifera, Choque-Durand et al. (2018)Choque-Durand, H., Huaita, A., Cárdenas, L.A. & Ramos, R. 2018. Effect of regrowth age in the ruminal degradation of pisonay (Erythrina sp) in Andean valley of Abancay. Journal of High Andean Research, 20(2): 189 - 202, ISSN: 2313-2957. http://doi.org/10.18271/ria.2018.363. found 70 % for Erythrina sp. Gutiérrez et al. (2015)Gutiérrez, D., Borjas, E., Rodríguez, R., Rodríguez, Z., Stuart, R. & Sarduy, L. 2015. Evaluación de la composición química y degradabilidad ruminal in situ de ensilaje mixto con Pennisetum purpureum cv. Cuba CT-169: Moringa oleifera. Avances en Investigación Agropecuaria, 19(3): 7-16, ISSN: 2638-1716. http://www.redalyc.org/articulo.oa?id=83743886002. obtained in situ DM degradability of 71.26 % in Moringa samples in a mixture of Cenchrus purpureus with Moringa (40:60), degradability of 69.79 % and 67.29 % degradability with 40 % Moringa and 60 % Cenchrus purpureus.
It is concluded that Moringa showed superior indicators in the parameters of ruminal degradation, such as in the in situ degradability of DM, followed in descending order by Erythrina, Leucaena and Glycine. However, they show promise for use in ruminant feeding. Studies on ruminal degradability are needed to determine the relation between cutting frequency and the effects of secondary metabolites.