ORIGINAL

Use of ground and extruded canola seeds in feed for 15-30 kg piglets

Uso de la semilla de canola molida y extrusada en la alimentación de lechones de 15-30 kg

Carina Scherer,¹ Ph.D, Antonio Furlan,² Ph.D, Ivan Moreira,² Ph.D, Angela Poveda P,³* Ph.D, Paulo Carvalho, ¹ Ph.D, Juliana Toledo,² Ph.D.

¹Universidade Estadual do Oeste do Paraná. Departamento de Zootecnia. Marechal Cândido Rondon, Paraná, Brasil CEP: 85960-000.
²Universidade Estadual de Maringá. Departamento de Zootecnia. Av. Colombo,5790, Maringá-Paraná, Brasil, CEP: 87020-900.
³Universidade Estadual de Londrina, Departamento de Zootecnia,Rodovia Celso Garcia Cid PR 445 Km 380, Londrina-Paraná, Brasil. CEP 86057-970.

*Correspondence: angelpov@gmail.com

Received: April 2014; Accepted: November 2014.

ABSTRACT

Objective. Determine the nutritional values of ground (SCI) or extruded (SCE) canola seed and evaluate its use in the performance of piglets from 15 to 30 kg. Materials and methods. Two experimental diets with canola seed were evaluated in a digestibility trial. We used 15 barrows with an initial weight of 19.79±1.43kg, distributed in a completely randomized design. In the performance, four experimental diets were evaluated consisting of a diet with soybean oil added (RAS), one with the of addition of canola oil (RAC) and two oil-free; one with 11% SCI included and one with 6% SCE (RSCE) included. 40 commercial hybrid piglets were used that had 15.25±1.5kg initial body weight, randomly distributed, in four treatments and five replicates; two animals per experimental unit. Results. The digestible energy values for SCI and SCE were 4.197 kcal/kg and 5.234 kcal/kg, respectively. The extrusion process improved the digestibility coefficients. Piglets fed with RSCI showed less daily weight gain (DWG) and F:G ratio. Conclusion. Results suggest that SCE can be included in diets of piglets from 15 to 30 kg until 6% without negatively affecting performance.

Key words: nimal performance, anti-nutritional factors, digestibility, economic viability (Source: AGROVOC).

RESUMEN

Objetivo. Determinar los valores nutricionales de las semillas de canola integral molida (SCI) y extrusada (SCE) y evaluar su influencia sobre el desempeño de lechones de 15 a 30 kg. Material y métodos. Se evaluaron dos dietas experimentales con semilla de canola en un ensayo de digestibilidad. Fueron utilizados 15 lechones machos, castrados, con peso inicial de 19.79±1.43kg, distribuidos en un diseño completamente al azar. En el desempeño se evaluaron cuatro dietas experimentales que consistieron de una dieta con adición de aceite de soya (RAS), una con adición de aceite de canola (RAC) y otras dos exentas de aceite; siendo una con la inclusión de 11% de SCI (RSCI) y otra con la inclusión de 6% de SCE (RSCE). Fueron utilizados 40 lechones híbridos comerciales, con peso vivo medio inicial de 15.25±1.5kg, distribuidos en un diseño experimental completamente al azar, con cuatro tratamientos, cinco repeticiones; siendo dos animales por unidad experimental. Resultados. Los valores de energía digestible para SCI y SCE en base seca fueron de 4.197 kcal/kg y 5.234 kcal/kg, respectivamente. El proceso de extrusión mejoró los coeficientes de digestibilidad. Los lechones alimentados con RSCI presentaron menor ganancia de peso (GPD) y peor conversión alimentaria (CA). Conclusiones. Los resultados indicaron que la SCE puede ser incluida en la dieta de lechones de 15 a 30 kg, hasta un nivel de 6% sin afectar el desempeño.

Palabras clave: Desempeño animal, digestibilidad, factores antinutricionales, viabilidad económica (Fuente: AGROVOC).

INTRODUCTION

Soy flour is the protein source most commonly used in pork production due to its high quality; however, the high cost of this feed has generated the search for alternative sources that reduce diet costs.

Canola is a variety of colza and is considered an option to substitute soy flour. It was genetically developed from colza (Brassica napus), which has a low glucosinolate content (≤3 µg/g) and the oil has less than 2% erucic acid (1). In spite of the fact that canola seed is not commonly used in animal diets, investigations have shown that this product has high amounts of protein, which allows its use as a soy flour substitute (2).

The chemical composition of canola can vary according to the genetic variety and environmental factors; however, the seed is considered to possess 23% raw protein and approximately 5.475 kcal/kg of raw energy, and the amino acid profile is compares favorably to that of soy flour (3). Whole canola seed contains from 36 to 40% excellent quality oil with less than 60 monounsaturated fatty acids and less than 7% saturated acids (4), which constitutes a source of energy that reduces the need to add oil to the diet.

The diet given to piglets should be digestible and have a high concentration of nutrients; feed should therefore undergo different processes that improve the quality of the diet (5). Among the production processes that determine the diet's physical form are flour, pelletizing and extrusion (6).

Few studies have been done on the nutritional evaluation of extruded canola seed in pigs. However, results up to now have demonstrated that using canola flour and other feed in extruded or pelletized form can be used to the partially substitute soy flour. Ahmed et al (7) determined the actual and apparent digestibility of extruded canola flour and concluded that extrusion improves apparent digestibility of raw protein, amino acids, raw energy and energy that can be metabolized. Therefore, Mariscal et al (8) determined the real, apparent and standardized digestibility coefficients in protein and amino acids of pelletized canola cake in recently weaned piglets. They concluded that the pelletizing process improves real digestibility of protein and amino acids.

The objective of this study was to determine the nutritional value of ground or extruded canola seeds and evaluate their use in diets for piglets in the initial phase (15 to 30 kg).

MATERIALS AND METHODS

Study site. The experiments were done in the Pork Breeding Sector of the Iguatemi Experimental Farm of the Universidad Estadual de Maringá (Paraná-Brazil), located at coordinates 23°21'S, 52°04'W, and at 564 meters above sea level.

Characterization of the feed. The variety of canola (Brassica napus) used was Hyola 401, donated by the Cooperativa de Caficultores y Agropecuaristas de Maringá (COCAMAR- Paraná-Brazil).

The canola seed was ground in a 2 mm sieve, one part was added to the diet in ground form and the other underwent an extrusion process using an Imbra 120 extruder from Imbramac, with 120 kg/hour capacity and an interior barrel temperature of 118°C and pressure at 1 to 2 atm.

Type of study. Experiment 1: Digestibility assay where ground canola seed (GCS) and extruded canola seed (ECS) were evaluated. Experiment 2: Determining productive parameters by evaluating four diets with 11% RSCI, 6% RSCE and two diets that include canola and soy oils.

Animals. Experiment 1: 15 barrows were used, commercial hybrids with an initial weight of 19.79±1.43, individually kept in metabolism cages. The experimental period lasted 10 days (five days of adaption to the cages and diets and five days of feces collection). Experiment 2: 40 hybrid commercial piglets were used (20 males and 20 females) with an initial weight of 15.25±1.50. The animals were held in cages suspended with plastic flooring and a front-feeding trough and nipple-type drinking dispenser.

Experiment design. Experiment 1: Completely random design with three treatments, five repetitions, with each experimental unit consisting of one piglet. Experiment 2: Completely random experimental design with four treatments, five repetitions and two animals per cage.

Treatments. Experiment 1: A control diet (CD) of corn and soy flour calculated to meet the requirements of the initial phase and according to the chemical composition and energy values of ingredients found in Brazilian tables for birds and pigs (9), GCS and ECS substituted in dry base, 20% of the CD, resulting in two experimental diets. Experiment 2: The experimental treatments consisted of four diets, one with a corn base and soy cake with soy oil added (DAS), another one of corn base and soy cake with the addition of canola oil (DAC) and anther two without oil and 11% inclusion of ground canola seeds (GCS) and other with 6% inclusion of ground extruded canola seed (GECS).

Diets were formulated according to the recommendations given by Rostagno et al (9), these being isoenergetic, isoprotein, isocalcitic and isophosphoric (Table 1). Diets and water were available during the whole experiment. Chemical and energy composition values were used as set out by Rostagno et al (9) with the exception of energy values of the canola seeds whose values were determined in the digestibility experiment previously described.

Nutritional management. Experiment 1: Diets were offered on two schedules, 60% at 08:00 hours and 40% at 16:00 hours. The total quantity offered each day was established according to the animal's daily consumption of the diet (DCD) during the adaption phase, based on metabolic weight (kg^0.75) of each experimental unit. Water was offered in the trough after consuming the diet in a proportion of 3.0 mL/g of food, calculated for each experimental unit, avoiding an excess of water consumption. Experiment 2: The animals received water and feed ad libitum during the whole experiment.

Methodology. Experiment 1: The total collection method was used and 2% iron oxide (Fe₂O₃) was used as a fecal marker to indicate the beginning and end of collection. The feces produced were collected once daily, stored in plastic bags and frozen at 18°C. At the end of the collection period the material was homogenized, dried in a forced ventilation stove (55°C), and ground in a hammer type grinder with a 1 mm sieve for laboratory analysis. Experiment 2: At the end of the experiment, the animals were weighed and total consumption was calculated to determine the daily consumption of the diet (DCD), daily weight gain (DWG), and feed conversion (FC).

At the beginning and end of the assay blood samples were collected via the anterior cava vein in tubes with heparin to determine nitrogen of the plasmatic urea (PUN). The samples were centrifuged (3,000 rpm for 15 minutes) to obtain plasma that was transferred to 1.5 mL micro tubes which were duly identified and stored in a freezer (-18°C) for later analysis. The PUN values were determined with the Uréia-PP® (Gold Analisa Diagnóstico) kit. The initial PUN results were used as a co-variable for the statistical analysis of the final PUN.

Laboratory analysis. Experiment 1: Feed and feces analysis was done at the Animal Nutrition Laboratory of the Universidad Estadual de Maringá. EB values were determined by means of a calorimetric pump (Parr Instrument Co.).

Data analysis. Experiment 1: The digestibility coefficients of dry material (CDMS), raw protein (CDPC), ether extract (CDEE), organic material (CDMO) and brute energy (CDEB) of the feed were calculated taking into account the total collection method according to Sakomura and Rostagno (10).

The values of digestible dry material (MSD), digestible protein (DP), digestible ether extract (DEE) digestible organic material (DOM) and digestible energy (DE) of the feed were calculated using the formula described by Sakomura and Rostagno (10).

The digestibility coefficients of the nutrients in canola seeds were submitted to variance analysis, using the statistical program SAEG.

Experiment 2: To verify the economic viability of including entire ground canola seed and extruded canola seed in diets, the cost of the diet (CD) was calculated and the cost of the diet per kilogram of live weight (CMD) according to the following formula: Yi(R$/kg)= Qi x Pi / Gi, where Yi= cost of the diet per kg of live weight gained in the i-th treatment; Qi= quantity of diet consumed in the i-th treatment; Pi= price per kg of diet used in the i-th treatment; Gi=weight gain in the i-th treatment. Later the economic efficiency indexes were calculated (EEI) and the cost (CI) according to the following formulas: EEI (%) = MCe/ CTei x 100 y IC (%) = CTei/ MCe x 100, where MCe= least cost of diet per kg gained observed among the treatments; CTei= cost of the treatment i considered.

Daily consumption diet (DCD), daily weight gain (DWG), feed conversion (AC), PUN and economic variables were analyzed using the SAEG statistical program.

RESULTS

Ground entire canola seeds presented higher values for ether extract, organic material, brute energy and less raw protein when compared to extruded canola seed. Values for calcium, total phosphorus and brute energy were similar among the seeds (Table 2).

The extruded canola seed presented higher values indicating that the extrusion process improved digestibility coefficients (Table 3) of the majority of the nutrients (p<0.05), except for the raw protein coefficient (CDPC), which was similar in both seeds.

The digestible energy values (DE), digestible ether extract (DEE), digestible organic material (DOM) and dry digestible material (DDM) of extruded canola seed were superior to the values of ground entire canola seeds (Table 4), demonstrating that the extrusion process improves the digestibility of those nutrients.

In the performance experiment, piglets fed with diets that contained ground canola seeds presented the least weight gain and worst feed conversion (p<0.10) when compared with the control diet (Table 5), the other treatments did not show differences between the evaluated variables.

The PUN concentration did not show differences between the treatments (p>0.05), indicating that the nitrogen present in the diets was used with the same efficiency and that the quality of the protein consumed was similar in all the treatments.

The economic analysis (Table 6) presented a lesser cost per kilogram of live weight (p>0.05) for the DAC diet when compared with the other diets.

The economic efficiency index and the cost index did not reveal differences among the treatments; however, the DAC diet and the DSCE diet reached a cost and economic index of 100%, these being the most efficient.

DISCUSSION

Variations found in the nutritional composition (Table 2) of the ground and extruded canola seed can be attributed principally to a loss of moisture and oil that occurred during the extrusion process, which can be observed in the dry material values and the ether extract; additionally, the extrusion process concentrated the protein portion of the feed. The conditions of the process can affect the chemical characteristics and the nutritional quality of the product (11).

It is evident that the extrusion process improves the digestibility coefficients of the nutrients principally due to the physical transformation of the starch grains, provoking a structural disorganization and favoring enzymatic action (9). The results obtained for ether extract can be due to the exercise of mechanical pressure during the extrusion process, breaking down the cellular membranes, and releasing the oil (10).

Similar results were found by Ahmed et al (7) and Seneviratne et al (11), where better digestibility coefficients were found in the extruded canola flour.

Results obtained in the performance experiment (Table 5) can be attributed to factors such as extrusion, where the process probably minimizes the effects of the anti-nutritional factors (erucic acid and glucosinolates) that diminished how the protein in the diet was used, interfering with the metabolism of iodine and other metabolic processes (12). In spite of including oil and canola oils, the nutritional quality was maintained.

Similar results were described by Peñuela-Sierra (2), who asserted that the quantity of the glucosinolates can explain the different responses obtained in the productive parameters. Montoya y Leterme (13), feeding pigs with different levels of canola flour and canola seed oil, did not observe differences in the feed conversion.

The low PUN values are related to taking greater advantage of nitrogen for tissue deposition, indicating that the quantity and quality of the amino acids added to the diet was adequate.

In conclusion, ground canola seeds and extruded canola seeds presented 4.197 and 5.234 kcal/kg of digestible energy in dry base, respectively, the extrusion process being an efficient method to improve the digestibility of the nutrients.

The inclusion of up to 6% extruded canola seed in the diets of piglets in the initial phase (15 to 30 kg) did not harm the productive parameters; however its use is conditioned to its availability and price so that the diets can be economically viable.

Acknowledgements

To COCAMAR for donating the canola seed used in this study.

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