Servicios personalizados
texto en 
Inglés (pdf)
Articulo en XML
Referencias del artículo
Curriculum ScienTI
Enviar articulo por email
Citado por SciELO 
Similares en
SciELO 
Permalink
In the world, swine population has had a sustained growth in recent years, due to the fast development of technology for production, nutrition and genetic improvement, so it constitutes a source of food and economic income for population (FAO 2020). However, pig feeding represents around 70% of production cost. Hence, the importance of seeking alternative sources to mitigate costs in pig production (Castro and Martínez 2015).
In Ecuador, there is a wide range of agricultural and agro-industrial by-products, viable for pig feeding. These include distillery residues (vinasses), tubers and taro foliage. In Pastaza province, for example, vinasses does not receive an adequate treatment. This residue is eliminated in water sources, which generates harmful effects for the environment, such as eutrophication and pollution of rivers (Zuñiga and Gandini 2013). Tubers and taro foliage, when supplied in natural state, cause irritation and a burning sensation in the mouth and throat of animals, which is explained by the high content of calcium oxalate crystals (Hang et al. 2011).
Nowadays, several researches are carried out with alternative foods, such as silages, which show favorable results in the productive performance and health of animals (Lezcano et al. 2017). Tubers and foliage of taro provide nutrients that favor growth of yeasts and lactic bacteria (Caicedo et al. 2015), and vinasses help to quickly reduce the pH of raw material until stabilizing it, so a good quality fermented product is achieved for its use in pig feeding (Lezcano et al. 2014).
Therefore, the objective of this study was to determine the chemical composition of a silage of taro tubers and foliage (Colocasia esculenta L. Schott) and its effect on productive indicators of rearing pigs.
Materials and Methods
Location. This research was carried out at the Bromatology Laboratory of the Universidad Estatal Amazónica (UEA), Puyo main campus, and at Buena Esperanza pig farm, located in San José parish, Santa Clara canton. The study area has a semi-warm or humid subtropical climate, with rainfall between 4,000 and 5,000 mm per year. It is located at an altitude between 500 to 900 meters above sea level, with relative humidity of 87% and mean minimum and maximum temperature between 18 and 36 ºC (INAMHI 2014 and Uvidia et al. 2014).
Preparation of the silage of tubers and taro foliage. Waste taro tubers and foliage came from San José parish, in Santa Clara canton. Once collected at Buena Esperanza pig farm, they were washed and drained for one hour, and then cut into a hammer mill, with a 2 cm sieve. Subsequently, homogeneous mixing was carried out for 5 minutes, at room temperature, on plastic and on a concrete floor under roof, with the ingredients that silage was composed of (table 1). Raw materials were placed as follows: 1) chopped tubers, 2) chopped foliage, 3) wheat powder, 4) sugar cane molasses, 5) vitaminized pecutrin, 6) calcium carbonate and 7) sugar cane vinasse. A part of this mixture was placed in five microsilos, with a capacity for 1 kg, and the rest was packed in black hermetic bags, of 50 kg. Food was kept indoors, protected from sunlight, for seven days before use.
Table 1 Formulation of silage of taro tubers and foliage
| Raw materials | Inclusion, % |
|---|---|
| Chopped taro tubers | 60.0 |
| Chopped taro foliage | 14.0 |
| Wheat powder | 10.0 |
| Sugar cane molasses | 5.0 |
| Vitaminized pecutrin 1 | 0.5 |
| Calcium carbonate | 0.5 |
| Sugar cane vinasse | 10.0 |
| Total | 100 |
1Each kg contains: calcium 17 to 20%, phosphorus 18%, NaCl 0.5 to 1%, magnesium 3.0%, biotin 50 mg, zinc 8,000 mg, manganese 1,500 mg, iron 500 mg, copper 2,000 mg, iodine 160 mg, cobalt 30 mg, selenium 70 mg, vitamin A 300,000 IU, vitamin D3 50,000 IU, vitamin E 100 IU, calcium-phosphorus ratio 1.3: 1, zinc-copper ratio 4: 1
Chemical analysis of the silage. Nutrient determination was conducted in the UEA bromatology laboratory. Verification of temperature and pH was carried out in five microsilos, on day seven of fermentation, according to procedures of Cherney and Cherney (2003) and Caicedo (2013). Dry matter (DM), crude fiber (CF), ash, crude protein (CP), ether extract (EE) and nitrogen-free extract (NFE) were determined according to AOAC (2005). Organic matter (OM) was the result of subtracting ash percent from 100. Gross energy (GE) was determined by calorimetry, with an adiabatic pump (Parr brand, model 1241). Analyzes were conducted by triplicate for each nutrient.
Animal management and facilities. Pigs were managed according to Animal Welfare regulations of the Republic of Ecuador (AGROCALIDAD 2017) and the experimental protocol, according to Sakomura and Rostagno (2007). For this study, 16 commercial crossbreed (Landrace x Belgian White) castrated male animals, of 45 days old and with an initial mean weight of 12 ± 2 kg were used. Each pig constituted an experimental unit. Animals were placed in individual cages, 1.0 mx 1.40 m (1.40 m2), equipped with a hanging cone feeder and a nipple drinker, located in a warehouse with 1-meter-high walls, concrete floor with rice husk of 20 cm and curtains to regulate the temperature. Water was available at will. Average ambient temperature in the facility was 24 ° C.
Food management. Treatments consisted of two diets: a control T0 (corn and protein concentrate) and T30 (inclusion of 30% of silage in the diet). Diets were formulated according to NRC (2012) procedures for rearing pigs (table 2). Intake was adjusted according to live weight of pigs (Rostagno et al. 2011). Food was provided twice a day in equal parts (8:00 a.m. and 3:00 p.m.).
Table 2 Composition and contribution of experimental diets on a dry basis (DB)
| Ingredients, % | Silage inclusion levels, % | |
|---|---|---|
| 0 | 30 | |
| Yellow corn | 49.2 | 21.2 |
| Wheat meal | 20.0 | 20.0 |
| Silage of taro tubers and foliage | - | 30.0 |
| Protein concentrate1 | 30.0 | 28.0 |
| Mineral premix for pigs2 | 0.4 | 0.4 |
| Sodium chloride | 0.4 | 0.4 |
| Calculated nutrients3 | ||
| CP, % | 18.19 | 18.64 |
| CF, % | 4.46 | 4.70 |
| Cost, dollars kg DM-1 | 0.62 | 0.45 |
1Ingredients: soybean paste, rice co-products, wheat, corn DDGS , wheat co-products, palm oil, bakery co-products, sugar cane molasses, calcium carbonate, sodium chloride, L-lysine 78%, dicalcium phosphate, propionic acid at 50%, sodium aluminosilicate, DL-methionine 99% and L-threonine 98%.
Nutrient contribution: protein 35%, fat 4%, fiber 5%, ash 7%, humidity 13%, lysine 0.92% and methionine 0.27%.
2Vitamin and mineral premix (vit A 2’300,000 IU, vit D3 466,667 IU, vit E - 5,000 IU, vit K3 667 mg, vit B1 333 mg; vit B2 1,000 mg, vit B6 400 mg, vit B12 4,000 μg, folic acid 67 mg, niacin 6,660 mg, pantothenic acid 4,000 mg, biotin 17 mg, choline 43 g, iron 26,667 mg, copper 41,667 mg, cobalt 183 mg, manganese 16,667 mg, zinc 26,667 mg, selenium 67 mg, iodine 267 mg, antioxidant 27 g, vehicle qsf 1,000 g).
3Calculated according to NRC (2012) and/or determined
Evaluation of productive indicators. After selecting animals for the experiment, they were dewormed with granulated Fenbendazole, at a rate of 10 g 100 kg LW-1. Pigs were individually weighed, every 7 days, with a 200 kg capacity Cardinal brand scale. Daily food intake (DFI), daily weight gain (DWG), food conversion (FC) and final weight (FW) were verified, according to Flores et al. (2015).
Experimental design. To examine the chemical composition data of silage (DM, OM, CP, CF, EE, ash, NFE and GE), descriptive statistics was used and, mean, standard deviation and coefficient of variation were determined. Results of productive indicators (DFI, DWG, FC and FW) were processed by the analysis of variance (Steel et al. 1997), according to a completely randomized design. Means were compared using Fisher (1954) test (P<0.05). All analyzes were performed with Infostat statistical program (Di Rienzo et al. 2017).
Results and Discussion
Chemical composition of silage of taro tubers and foliage. On the seventh day of production, silage showed an adequate performance of pH and temperature, as well as an appreciable content of DM, CP, NFE, GE and low levels of CF, ash and EE (table 3).
Table 3 Chemical composition of silage of taro tubers and foliage
| Chemical components | Mean | Standard deviation | Coefficient of variation |
|---|---|---|---|
| pH | 4.39 | 0.50 | 3.26 |
| Temperature, ºC | 22 | 0.50 | 2.27 |
| DM, % | 30.91 | 0.45 | 5.80 |
| OM, % | 95.25 | 0.70 | 0.84 |
| CP, % | 12.07 | 0.37 | 3.49 |
| CF, % | 3.24 | 0.89 | 3.25 |
| EE, % | 2.89 | 0.48 | 3.44 |
| Ashes, % | 4.74 | 0.70 | 4.08 |
| NFE, % | 77.03 | 3.16 | 6.82 |
| GE, kJ g DM-1 | 17.88 | 1.36 | 12.16 |
Values of pH, temperature and DM of silage are within the established range for the production of good quality silages. The pH is a very important indicator for silage production, and must be kept at values between 3.8 and 4.5 to achieve good stability and food preservation for a long time (López et al. 2013, Borreani et al. 2017 and Caicedo et al. 2019). Low pH inhibits the development of ensiled raw material decomposing microorganisms (Caicedo et al. 2016 and Wang et al. 2017).
Optimal temperature for silage preservation depends on the microorganisms that develop during the process. In general, optimal range for growth of lactic bacteria and yeasts is between 20 and 30 °C (Castillo and Barrera 2013 and Granados-Marín et al. 2014). However, temperatures below 10 °C or above 37 °C affect the fermentation process, leading to poor quality silages with low aerobic stability (Bernardes et al. 2018 and Zhou et al. 2019).
Regarding DM content, Tomich et al. (2003) and Nkosi et al. (2016) reported that a good quality silage must contain a DM percentage superior to 30%, in order to limit the development of putrefactive microorganisms in the feed. In this study, DM content is within that range. When low DM raw materials are ensiled, with values lower than 20%, it is necessary to include drying material to guarantee a good conservation of the product (Borrás-Sandoval et al. 2017).
CP concentration of silage was improved with respect to the tuber in natural state (8.48%) (Caicedo 2015). This may be due to the inclusion of foliage (Buntha et al. 2008), as well as the presence of microbial protein, developed during the fermentation process (Gutiérrez and Gómez 2008, Ritala et al. 2017 and Caicedo et al. 2019).
The silage demonstrated low concentrations of EE, CF and ash. These results are similar to those reported by Himeda et al. (2012) and Caicedo (2015) for taro varieties in their natural state. It should be noted that EE and CF values of silage are within the range allowed for their use in pigs during rearing stage (Bertechini 2013 and Aragadvay et al. 2016).
Silage had a high content of NFE and GE, which is explained by the concentration of carbohydrates in the tuber (Caicedo 2015). For this reason, this food is recommended as an excellent energy source for humans and animals (Ogunlakin et al. 2012 and Caicedo 2015).
Productive indicators of rearing pigs, fed silage of taro tubers and foliage. During the study, there were no diarrhea or animal deaths. There was also no effect (P> 0.05) among treatments for the studied indicators: DFI, DWG, FC and FW (table 4). These results coincide with previous research, developed in pigs that were fed taro tuber silage (Caicedo et al. 2019). The optimal productive performance of animals fed the alternative diet is related to fermentation process.
Table 4 Productive indicators of rearing pigs, fed silage of taro tubers and foliage
| Variables | Silage inclusion levels, % | SE ± | P value | |
|---|---|---|---|---|
| 0 | 30 | |||
| DFI (kg) | 1.15 | 1.11 | 0.93 | P=0.3582 |
| DWG (kg) | 0.55 | 0.53 | 0.14 | P=0.3261 |
| FC (kg/kg) | 2.08 | 2.09 | 0.40 | P=0.7399 |
| FW (kg) | 30.50 | 29.06 | 3.34 | P=0.1323 |
DFI: daily food intake, DWG: daily weight gain, FC: food conversion, FW: final weight, SE: standard error
This technique leads to improvements of antioxidant phenolic compounds of raw material, product of microorganisms that develop in this medium through the metabolic route, due to extracellular enzymatic action (Gunawan et al. 2015, Dey et al. 2016 and Aruna et al. 2017). Antioxidant peptides produced by microorganisms are successfully used in the food industry to formulate functional foods (He et al. 2012). In fact, bioactive components can modulate the immune system in the animal (Ricci et al. 2010). Anyasi et al. (2018) and Mahloko et al. (2019) point out that health benefits, derived from compounds of an antioxidant nature, occur in symbiosis with the intestinal microbiota, which metabolizes and releases them for their use. In addition, the beneficial microbiota developed in the silage could act as a probiotic, limiting the growth of pathogenic microorganisms and guaranteeing intestinal health of animals, in addition to participating in protein and vitamin synthesis and improving food digestibility (Yang et al. 2015, Chandrasekara and Kumar 2016 and Liao and Nyachoti 2017).
In roots and tubers, the mixture of small granules and low content of highly soluble dietary fiber promotes its use as an excellent source of carbohydrates for special extruded products, such as weaning diets (Vargas and Hernández 2013). These, due to their significant contribution to intestinal integrity, allow an adequate nutrient absorption, without affecting weight gain (Pérez-Balladares et al. 2019 and Rinaldo 2020).
