**Abstract**

The main limiting factor in livestock production is fluctuation in the quantity and quality of forage resources. Therefore, it is necessary to determine the chemical composition and degradation kinetics of the feed that is used for ruminant feeding regime. *Erythrina edulis* (*Euphorbia edulis*) is a multipurpose legume plant with high nutritional quality and possibly the capacity to meet dairy ruminant requirements. The study showed that the two phenological stages leaves (SV) and sheath without seed (SF) had greater CP contents than other sources than are typically used for feeding ruminants. Nevertheless, the SF had lower fiber contents, so the highest DM and CP degradation parameters than SV, it was obtained. Consequently, *E. edulis* might be considered as a forage alternative for inclusion in ruminant feeding.

**Keywords:** shrubs, phenological stages, chemical composition, degradability, *Erythrina edulis*

## **1. Introduction**

The sustainability of livestock farming systems plays a central role in addressing policies aimed at sustained and planned rural development [1]. In Latin America, the dairy sector has been more dynamic in the past 20 years than in the rest of the world with an average growth of 12.5% for its 3.15 million milk producers [2]. Dairy production in Ecuador is concentrated mostly in the Andean highlands, the Sierra Region [3]. In addition, FAO [4] stated that in Ecuador the cattle breeding systems tend to be extensive (5 million hectares dedicated to livestock with 4.1 million cattle) with low productivity (5.38 liters of milk per cow) and with poor use of pastures.

The crude protein (CP) and energy requirements for ruminants are the most important limitans in the livestock industry worldwide [5–8]. Soybean products are commonly fed concentrates in highly productive ruminants because of their high content of protein and good profile in essential amino acids [9–11], although the high global demand has resulted in price increases. In the Ecuadorian Highland Region approximately 57% of livestock farms are less than 10 hectares, and they are managed as smallholder production with low intensification levels and economic incomes [4], so in these production systems the use of soybean meal is too expensive. According to Camero et al. [12], feeding leguminous fodder that is high in protein, can improve rumen fermentation parameters leading to increased digestibility and intake of lowquality feeds, and hence improved animal production. For this reason, for the Ecuadorian Andean Region is necessary to research new forage alternatives to use in ruminant feeding. In this sense, trees and shrubs have had an increasing interest due to their high potential for supplying fodder which provides greater nutritive value and environmental services [1, 13–15].

*Erythrina edulis* is a leguminous plant with a wide range of uses from human (mainly seeds) to animal (forage) diets, as well as in the recovery of the soil nitrogen content [16–18]. Furthermore, this species has a higher protein content (ranging from 18 to 25%) than other legumes and is similar in terms of quality to egg protein [19–21]. South America countries such as Colombia, Peru, and Venezuela have already studied this species and its potential for use in animal production [12, 18, 22–24]. However, little available information on this multipurpose plant in the context of Ecuadorian conditions is available, despite that, *E. edulis* can be found as a wild plant, the lack of knowledge on its properties and potential for livestock nutrition, this species has gone unnoticed with a latent danger of extinction.

## **2. Materials and methods**

The study was performed in (INIAP), Pichincha, Ecuador and all experimental procedures were approved by them.

#### **2.1 Study area**

The study was carried out in Valle de los Chillos, Pichincha province, located in the northern Highland region of Ecuador. The soil type in the area of study is Molisols, at 45.88%, followed by Andisols at 17.88% [25]. The climatic conditions predominant in this zone are, on average temperature (22.9°C), rainfall (1200 mm/year), relative humidity (78%), and an altitude of 2200 m.a.s.l.

#### **2.2 Experimental design, collection, and preparation of samples**

For the experimental procedure, 150 vegetative stakes of *E. edulis* were planted with a 6 6 m distance between them. After 2 years of establishment, the trees of *E. edulis* were randomly divided into two equilibrate groups to assess the vegetative stage (SV = leaf) and fructification stage (SV = previously seed was removed). The leaf samples were cut 50–60 cm from the tip of the second youngest branch at the top of each tree. Thereafter, the 60 samples of each phenological stage were pooled, according to SV and SF, giving 9 samples, and then frozen at 20°C for further analysis. Before analyses, samples were conditioned at 60°C for 48 h, and then milled and homogenized through a cyclone mill (Model 4 Wiley Mill, Thomas Scientific, Swedesboro, NJ, EUA) with a 1 mm mesh, and for *in situ* rumen incubation, samples were milled with a 2 mm mesh.

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

#### **2.3 Chemical analysis**

All determinations were performed, according to official reference methods [26]. Thus, Dry matter (DM) was determined at 103°C for 24 h, and ashes burnt at 550°C for 5 h. Whereas wall cell components such as crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) using the Ankom200 Fiber Analyzer (Ankom Technology, Fairport, NY, USA). Furthermore, Crude protein (CP) was calculated as a percentage of N � 6.25 using the Kjeldahl method. Besides this, phenols and total tannins were determined using the Folin–Ciocalteu method, before and after the treatment of extracts with polyvinylpolypyrrolidone [27].

#### **2.4 In situ rumen incubation**

For this study, two 4-year-old Holstein non-lactating cows, (650 � 5.0 kg BW) equipped with permanent rumen fistula were used. The cows, were subjected to a 15-d adaptation period, being fed (2% of BW) with only *Pennisetum clandestinum* (chemical composition, as % DM; ash, 7%; CP, 13.2; NDF, 38%; ADF, 26%; CF, 25.0%; and EE, 1.53). Throughout the experiment, the cows had free access to mineral and vitamin block (Na, 12 g; Ca, 20 g; P,10 g; Mg, 0.10 g; S, 0.29 g; Zn, 0.16 g; Mn, 0.12 g; Fe, 0.12 g; I, 0.020 g; Co, 0.002 g; Se, 0.003 g; Zinc, 0.16 g; and Cu, 0.002 g; Favetex, Favesal, Ecuador, milk production).

The DM and CP *in situ* degradability were carried out by incubating nylon bags (Ankom Technology Corporation, Fairport, NY, USA) in the rumen, which was 10 � 20 cm, 47 μm, pore size, containing 10 g of samples. Previously, zero-hour disappearance was estimated by washing duplicate bags containing feed samples in cold water (without passing through the rumen). After that, the samples were incubated in duplicate in the rumen for 3, 6, 12, 24, 36, 48, and 72, h, according to Aufrère [28] and NRC [29], before feeding at 0830 h. Once the bags were removed from rumen incubation, were immediately washed with clean water several times (three washing cycles of 5 min). They were also frozen at �20°C for 24 h to halt fermentative activity. After all this, the bags were dried at 60°C for 48 h, weighed, and so the residues were mixed for chemical analysis. Finally, using the equation of Orskov and Mcdonald [30], DM and CP degradation parameters were calculated:

$$D = a + b(\mathbf{1} - \mathbf{e} - \mathbf{c}\mathbf{t}).\tag{1}$$

where *D* is the fraction corresponding to the disappearance of either DM or CP at time t; *α* is an intercept representing the DM or CP soluble fraction; *b* is the fraction of insoluble but potentially degradable DM or CP; *c* is the rate of disappearance of fraction *b*; t is incubation time. The non-linear parameters *α, b*, and *c* were estimated using an interactive least-squares procedure of SAS (v. 9.4; SAS Institute Inc., Cary, NC). Therefore, the effective degradability (ED) of DM and CP was calculated using Equation:

$$\mathbf{ED} = \alpha + [\mathbf{bc}/(c+k)],\tag{2}$$

where *α, b*, and *c* are the same parameters as described earlier, and *k* is the estimated solid passage rate. In this study, we reported a *k* 6%/h for most lactation feeding conditions INRA [31], and according to low–middle–high level of intake (2, 5, and 8%/h, respectively).
