1. Introduction
Meat production in Ecuador, with a national output of 227,769 metric tons and a pig population of 1,969,922, of which 1,019,570 are used for fattening, is a significant contributor to employment and food security in the country, generating 80,000 jobs [
1]. The predominant production system in Ecuador is backyard family production, comprising 96% of the industry. There are also a few commercial (3%) and industrial (1%) farms [
2].
The backyard pig farming system in Ecuador relies heavily on concentrated feeds, often (45% of pig producers) supplemented with alternative feed ingredients derived from household kitchen leftovers and agricultural crop by-products [
3,
4].
Feed accounts for over 65% of total production costs in pork production in Ecuador [
5], and the most commonly used ingredients in concentrate preparation are cereals and oilseed meals [
6], with corn making up 50–70% of cereals [
7]. However, agricultural production generates residues that are not properly managed, leading to negative environmental consequences [
8]. Ecuador generates agricultural residues from products such as sugar cane, rice, corn, bananas, and tubers such as potatoes [
9]. Additionally, taro (
Colocacia esculenta (L.) Schott) generates a non-exportable rejection of 7.5% of a production of 700,000 boxes per year [
10].
Traditional farming systems, such as the backyard system, in Ecuador have the advantage of reducing costs through the use of alternative products in animal feed [
11]. These systems are also of great economic significance for rural producers [
12]. The introduction of alternative feedstuffs for pig rearing brings benefits in several areas: (i) economic and productive, as their nutritional content can replace traditional feeds without negatively impacting animal production [
13,
14,
15] and reducing production costs [
16,
17]; (ii) food security, by reducing competition with other staple foods for human consumption [
18]; and (iii) environmental, by reducing the disposal of crop residues and promoting crop diversification, which helps to decrease the environmental impact of corn production [
18].
In tropical regions of Ecuador, alternative feed ingredients used in pig farming include cassava (
Manihot esculenta), plantain (
Musa paradisiaca), pumpkin (
Cucurbita maxima), tagua (
Phytelephas aecuatorialis), and taro (
Colocacia esculenta (
L.)
Schott) [
19]. To optimize the use of these feeds, it is important to analyze their nutritional content, suitability for animal feeding, and the physiological and/or productive stages of the animal [
7]. Backyard producers typically use corn as the primary feed for pigs, which is supplemented with plantain, pumpkin, cassava, tagua, rice powder, and taro according to availability [
20].
Taro grown in Ecuador is primarily exported to the USA and Puerto Rico due to a lack of consumption culture in the country of origin [
21]. However, when the product does not meet size and shape standards for human consumption, it is used as animal feed [
19]. Taro can be grown throughout the year in Ecuador’s tropical climate, resulting in an annual production of 17 metric tons [
22].
Cassava is grown by small farmers in Ecuador year-round, at elevations ranging from near sea level to 1620 m above sea level. Ecuador has approximately 22,000 hectares [
23] dedicated to cassava cultivation. It is frequently used for animal feed production, particularly the tuber, although the stem and leaves are also consumed fresh [
24].
According to the Food and Agriculture Organization (FAO) [
25], cassava is the fourth most important feed commodity after rice, wheat, and corn, with a starch content ranging from 55–77% [
26], predominantly composed of amylopectin and a smaller amount of amylose. Cassava has a higher caloric content than other tubers, including potatoes [
27]. Its low retrogradation starch content facilitates digestion and utilization by animals [
24].
Taro has high-quality starch [
17] due to its branched amylopectin, which facilitates the absorption and entry of water into intermolecular spaces, increasing solubility [
28]. These characteristics make it suitable for feeding monogastric animals, such as pigs, and because taro starch is finely textured, it can be fed to young pigs [
29].
According to previous research [
30], cassava and taro primarily provide simple carbohydrates that are easily digestible for monogastric animals. However, further investigation is needed to determine their impact on animal health and growth [
31]. These alternatives contain anti-nutritional factors or toxins that can negatively affect health and productivity, and should therefore not be fed raw [
32,
33]. Both cassava and taro contain hydrocyanic acid (HCN) [
34], oxalates, and phytates [
17,
28,
29,
35], which can reduce the assimilation of nutrients [
19] by binding with minerals such as calcium, magnesium, and iron, resulting in the formation of mineral salts that inhibit gut digestion [
28]. While these components have not reached toxic levels, they can still affect animal health [
28]. However, various treatments such as high temperature exposure or ensiling can significantly reduce the percentage of antinutrients in the feed [
35,
36,
37,
38], resulting in a more suitable feed for consumption [
28,
35,
39].
Ecuadorian backyard pig producers in southern Manabí who sell animals directly for slaughter usually supply cooked cassava and taro as feed, supplemented with balanced feed [
20]. In order to support the production and marketing of backyard pigs, it is crucial to understand their growth performance and standardize the most suitable feed formulation. Previous research has investigated the use of cassava or taro as alternatives to traditional pig feed [
29,
40,
41], but there is very limited information available on the use of simultaneous cassava and taro formulations in pig feed.
The main goal of this study was to evaluate the effectiveness of using cassava and taro as alternative feed ingredients in the growth and fattening phase of pigs in order to enhance production conditions in Ecuadorian backyard pig-producing communities.
2. Materials and Methods
2.1. Geographical Location
This experiment was conducted in two locations in Ecuador: the Quinindé canton within the province of Esmeraldas and the Río Chico Parish within the Portoviejo canton of the province of Manabí (see
Figure 1). These locations, which are situated in the Ecuadorian tropics, have average annual temperatures of 23–26 °C (00°13′33″ N and 73° 26′00″ E) and 25 °C (1°0′0″ S and 80°26′0″ W), respectively [
42,
43].
2.2. Data Collection and Experimental Diets
A total of 42 castrated crossbreed pigs (male and female) aged sixty days were used in the study. Before the experiment began, the pigs were given a 10-day period of adaptation to the location and a progressive change in their feed. It is worth noting that the volume of experimental feed was gradually increased every 5 days.
The pigs used in the study were creole pigs mixed with the Pretrain breed from small pig producers in the vicinity of the experimental location. The pigs selected for the study had similar weight at 45 days of birth, ensuring a high level of uniformity. The animals were transferred from local producers to the experimental location, where they were individually identified and vaccinated against African swine fever. They were given an acclimation period until they reached 60 days of age.
The animals were randomly divided into six groups (seven animals per group), corresponding to three different feeding diets (T1, T2, and T3) and two geographical locations (Quinindé, Ecuador and Río Chico, Venezuela). The pigs were housed in handmade pigsties with cement flooring, cement-plastered brick walls, zinc roofing (
Figure 2), and a stocking density of 1.25 m
2 per animal for the duration of the 100-day experiment. The pigsties had a trough large enough for all seven pigs in each group to feed simultaneously and a drinker with running water. The animals were exposed to natural light during the day and artificial light at night to protect against the common vampire bat (Desmodus rotundus). The temperature in both locations was similar throughout the trial.
The feed diets were formulated using the Excel program in the Microsoft Office 365
® suite, utilizing the scoring method [
44]. The ingredients used were corn, rice powder, red palm oil, cassava, taro, and a protein concentrate for growth and fattening. Both cassava and taro were purchased fresh, with the tuber specifically used in the pig feed. The protein concentrate was sourced from the company “Bio alimentar” (Pelileo, Ecuador). This composition ensured that the pigs’ protein requirements, as well as their vitamin and mineral needs, were met.
To design complete diets, three replicates of 200 g of cassava tuber and three replicates of 200 g of taro tuber were analyzed in the chemical laboratory of the University of the South of Manabí (UNESUM) and the laboratory Multianalityca S.A. (Quito, Ecuador) (certified SAE LEN 09-008). This was done after the tubers were cooked for 30 min to determine their nutritional composition. After the chemical analysis of both feed alternatives was completed, the diets were formulated based on the nutritional needs of the pigs according to their reproductive stage (i.e., growth and fattening). The feed without corn replacement was provided in meal form, while those with cassava and taro were given wet. The cassava and taro were chopped, cooked for approximately thirty minutes or until softened, and salted. The diet with alternative feed ingredients was prepared daily, divided into two portions, and provided twice a day at 8 am and 3 pm for the entire 100-day duration of the experiment.
At the start of the experiment, the pigs were given 8.96 kg of feed per week, which was increased weekly according to the Genetiporc table for fattening pigs [
45]. This resulted in a total of 22.47 kg of feed being provided in the final week. It was not necessary to take into account the feed that was not consumed, as all batches were fully consumed by the pigs. There were no instances of mortality among the 42 animals during the trial, and all remained healthy throughout the experiment.
2.3. Measurement for Production Performance and Digestibility
The productive performance of the animals was measured through live weight (kg), height (cm), and length (cm) of the animals, as well as their feed conversion ratio. Weight, height, and length were obtained individually by placing the animals in a cage that had previously been placed on a high-precision digital scale (Montero TCS300JC61Z (Quito, Ecuador), with a maximum capacity of 300 kg and a minimum of 2000 g (d = 100 g)). The feed conversion was calculated in each group of animals (T1, T2, and T3) using the ratio between the feed administered and the average weight gain [
45]. The weighing and measurement (height and length) of the animals was carried out every 21 days, for a total of five data collections, three during the rearing phase and two during the fattening phase.
At the end of the experiment, the pigs were slaughtered in accordance with Ecuadorian animal welfare regulations [
46], which involve stunning and bleeding after 10 h of fasting. To analyze the apparent digestion, a sample of 150 g of ileum was collected from 30 pigs (5 animals per group) and subsequently frozen at −20 °C for a period of less than 5 days [
31]. The following characteristics were analyzed in each ileum sample (the method of analysis is specified in brackets): moisture (Association of Official Agricultural Chemists (AOAC) 925.10); crude protein (AOAC 2001.11); fat (AOAC 2003.06); ash (AOAC 923.03); pH (Ecuadorian Technical Standard (NTE) INEN ISO 4316:2014m); crude fiber (NTE INEN 522:2013). The calories, carbohydrates, and dry matter of the ileum were estimated through the following calculations, based on methods established by Maclean et al. [
47]:
Calories = (carbohydrate (g) × 4) + (protein (g) × 4) + (fat (g) × 8) + (fiber (g) × 4);
Carbohydrate = 100 − (moisture + fiber + fat + protein + ash);
Dry matter = (initial weight − dry weight)/initial weight.
The determination of the apparent digestibility was carried out by applying the following equation of Lachmann and Febres [
48], as adapted by Pico Dominguez [
49]:
NI (nutrient ingested) represents 15% of the protein content of the diet received by the animal at the end of the trial, while NH (nutrient in ileum) is the percentage of protein from the chemical analysis of the ileum.
2.4. Economic Analysis
The economic benefits of using alternative feeds in pig rearing and fattening were evaluated. This process took into account the initial cost of acquiring and transporting the animals, as well as the cost of setting up housing facilities for the animals. Feeding and health costs during the experiment, as well as costs related to slaughtering and cleaning utensils, were also considered. The economic analysis was conducted using a cash-flow approach, in which costs and revenues were estimated, resulting in the application of the financial ratio benefit–cost ratio and the unit cost of pork according to the treatments [
50].
2.5. Statistical Analysis
The data were analyzed using two completely randomized Analysis of Variance (ANOVA) models: one for body traits and feed conversion and one for ileal traits. For the analysis of the effects of body measurements and feed conversion, a factorial arrangement of balanced repeated measures was applied. The model included the variables of geographic location (L), treatment (T), time factor (FT), and their interaction (L × T × FT) (Equation (1)). For the model with an ileum chemical analysis, the model included variables of geographical location (L), treatment (T), and their interaction (L × T). The LSD test was used to compare LSMEANS, with a significance level set at
p < 0.05.
where: µ is the overall mean, L is the geographical location, T is the feeding or diet system treatment, FT is time factor, LT is the interaction location and feeding, LFT is the interaction location and time factor, TFT is the interaction feeding and time factor, LTFT is the interaction location, feeding and time factor, ε is the sampling error, and ijk is for any value of ijk.
To further analyze the effects of the various factors on body traits and feed conversion, regression analyses were performed. The economic parameters were also analyzed.
Statistical analysis was conducted using Statistica 12.0 for Windows and InfoStat 2020e software.
4. Conclusions
The combination of cooked cassava and taro, administered in equal proportions, and following the traditional practice of Ecuadorian backyard pig producers, has been shown to have a chemical composition suitable for use as an alternative in pig feed, allowing for a reduction of almost 20% in the amount of corn in the diet.
The combined use of cooked cassava and taro in the feed formulation for backyard pigs has been demonstrated to be a valid alternative to corn. In terms of production performance during growth and fattening, the assimilation of dietary nitrogen, reduced dependence on the rearing environment, and the inclusion of 42% cassava and taro in the formulation is an effective option.
The combined use of cooked cassava and taro drawn from crop surpluses or by-products in the feeding of backyard pigs in Ecuador contributes to the circular economy by significantly reducing production costs, thereby improving the average benefit/cost balance. Additionally, it also helps to reduce environmental impacts by utilizing local inputs and reducing waste production.