*Nutritional Potential of* Erythrina edulis *as a Forage Alternative for Supplementation… DOI: http://dx.doi.org/10.5772/intechopen.107496*

*1 SV, leaves.*

*2 SF, sheath without seeds.*

*3 NFE, N-free extract (or non-fiber carbohydrates) = OM CP CF. <sup>4</sup>*

*MP, was calculated based on 13 kg of DMI, according to NRC (2001); SEM, standard error of the mean.*

#### **Table 1.**

*Chemical composition of* Erythrina edulis *(leaves and sheath without seed).*

feed. Overall, the two studied phenological stages showed high CP contents (>20% on DM basis) in comparison to the common grasses used in the Andes region (*P. clandestinum*, 13.2%; *D. glomerata L*., 18.4%; and *L. perenne*, 17%, respectively). In the same way, our CP contents obtained in *E. edulis* are similar to the reported for other legume plants *Medicago sativa* (22%) and *Trifolium pratense* (23%), respectively [36]. Additionality, our results were similar to those reported by Rosales (CP, 25%) [13], Bedoya et al. (CP, 18%) [16], Intiquilla et al. (CP, 22%) Perez et al. (CP, 20%) [22], and Pérez et al. (CP, 23%) [42], when they determined CP contents in leaves of *E. edulis.* Some studies have showed that, CP contents less than 7% in DM basis, are not adequate for feeding ruminants [43–45]. Based on our results, the *E. edulis* had enough CP contents to supply the requirements of protein and ammonia need by rumen

microbial [40, 45, 46]. Possibly, this could explain the no correlations detected between CP contents and DM degradability for SV (*p* = 0.97) and SF (*p* = 0.95), as shown in **Table 2**.

With regard to the fiber contents, a study with leaves of *E. edulis* reported similar NDF contents (61 vs. 62%) to our work [13], and greater compared to those obtained by Naranjo [35] (62 vs. 50%). Whereas other researchers have reported in other varieties of *Erythrina (indica, subumbrans, and variegata)* lower NDF contents (54%, on average, on DM basis) than *E. edulis* [12, 18]*.* Positive correlations were detected between CP and NDF contents (*r* = 0.99; *p* < 0.001; **Table 2**), such as it has been seen in studies with pastures.

In the same way, Rosales [13] and Naranjo [35] reported lower ADF contents than our study (ranged from 45 to 26%), but this last author worked with other varieties, so cannot be comparable. Anyhow, in this work, SF showed lower ADF contents that above mentioned studies. The NDF stimulates the rumination and salivation, being important for remaining the normal rumen function [47, 48]. Nevertheless, negative correlations have been observed on DMI when NDF contents is above the limit require for ruminants (35–28%, in DM basis) [49, 50]. For this reason, the NDF content of forages is a good predictor to know its gut fill capacity, reflecting its nutritional value [51].

Differences on chemical composition between studied phenological stages, were reflected in the nutritive value, as shown in **Table 1**. The NEL contents were greater in SF than SV (NEL, 1.47 vs. 1.43 0.06 Mcal kg/DM; *p* = 0.010) with a tendency in the MP contents (1227 vs. 1053 g/d; *p* = 0.070). Analyzing the correlations, the NEL contents in SV were positively correlated with OM, CP, NFE and NDF (*r* = 0.99; *p* < 0.001) contents, but no correlated for SF (*r* = ̶0.99; *p* < 0.001). On the contrary, MP contents showed be positively correlated with CP, NFE and NDF contents in both phenological stages (*r* = 0.99; *p* < 0.001), as shown in **Table 2**.

Effects of condensed tannins on feeding efficiency, N losses and animal health are highly relevant, and a greater understanding of how grazing management might be refined to enable these potential benefits to be realized is critical [15, 52]. Several studies [43, 52–54] stated that temperate legumes contain moderate levels of secondary compounds, such as condensed tannins and flavonoid which could reduce environmental problems by increasing nitrogen use efficiency in protein utilization. In this sense, several studies have showed that antinutritional factors at low concentrations (20– 40 g kg/DM) are nutritionally beneficial through decreased degradation of dietary protein in the rumen, and increase protein availability for digestion and absorption leading to good animal performance [15, 44]. Based on these evidence, *E. edulis* in both phenological stages showed lower antinutritional levels (<2% in DM basis) which was similar to the reported by Rosales [13]. Therefore, theoretically, the studied phenological stages (SV and SF, respectively) should not represent a nutritional problem in feeding ruminants according with Moore et al. [34] and Mehrez and Keely [55]. Although, we hypothesized that the latex or resins presents in the plant could inhibit the initial colonization of rumen microbes. Anyway, it must be confirmed with more studies.
