Conocimiento Anco: 3 cosas que se deben de saber a cerca de las bentonitas

La bentonita puede ser empleada en la nutrición animal como adsorbente de toxina y para reducir la biodisponibilidad de toxinas de alimento contaminado en el intestino animal. Es un material de fina arcilla extraído de la tierra. La mayoría de las bentonitas se forman por la alteración de ceniza volcánica en ambientes marinos y se producen como capas intercaladas entre otros tipos de rocas (como se puede ver en la imagen arriba).

La bentonita se define como un material de origen natural que se compone predominantemente del mineral de arcilla esmectita. La capacidad de intercambio catiónico (CEC, por sus siglas en inglés) y la superficie específica de las esmectitas son considerablemente mayores que las de otras familias de arcillas. Su capacidad de absorción es hasta 8 veces mayor que otras arcillas.

Sin embargo, hay algunas cosas que debe saber antes de aplicar la bentonita en la alimentación animal:
1. No todas las bentonitas son iguales
2. La mejor prueba de la eficacia sigue siendo in vivo
3. Sólo un tipo de bentonita está aprobada en la UE para la adsorción de micotoxinas

1. No todas las bentonitas son iguales
Las bentonitas son materiales de arcillas coloidales y plásticos compuestos en gran parte de montmorillonita (una especie de esmectita dioctaédrica). Las propiedades de las bentonitas pueden variar considerablemente dependiendo del origen geológico y cualquier modificación posterior a la extracción. Sus características individuales tienen una influencia notable sobre su uso económico.

A pesar de la nomenclatura genérica de la bentonita disponible en el mercado, varias propiedades físico-químicas han sido identificadas como poseedoras de una posible correlación con la adsorción de micotoxinas y por lo tanto, podrían ser utilizados para categorizar los diferentes tipos disponibles.

Estas características incluyen:
• capacidad de intercambio catiónico (CEC), K+, Na+, Mg++ y Ca++ intercambiables
• pH
• hinchamiento lineal,
• fracción mineral
• humedad relativa
• espaciado d (distancia interplanar d)

Papel del espaciado d para la adsorción de zearalenona
La adsorción de las arcillas no se limita a la superficie de las partículas de arcilla, sino que se extiende también al espacio entre capas de la arcilla. Este espacio entre capas, caracterizado por el espaciado d (distancia interplanar), se puede determinar con difracción de rayos X (XRD, por sus siglas en inglés) y es restrictivo para la formación de una o más capas adsorbentes. Este espacio puede aumentar si la arcilla se hincha, lo que aumenta el número de sitios de unión.
Las pruebas de adsorción in vitro han demostrado que existe una correlación positiva entre la adsorción de zearalenona y el espaciado d en los productos a base de bentonita disponibles comercialmente, es decir, gran espaciado d se asoció con un mayor % de adsorción de zearalenona. (De Mil et al 2015). El espaciado d varió de 9.2 a 21.5 (10-10 m) en 16 productos diferentes que contienen material de bentonita, mostrando la gran variación del material disponible.
La diferencia entre bentonitas cis y trans para la adsorción de aflatoxina

Datos científicos recientes (Vekiru et al 2015) que evaluaron diferentes tipos de bentonitas para la eficacia de adsorción in vitro en relación con aflaxtoxina B1, han demostrado que la mayor parte de las bentonitas Ca- o Na- evaluadas fueron efectivas. Sin embargo, bentonitas cis fueron más eficaces que bentonitas trans.

Las esmectitas dioctaédricas que se encuentran en la bentonita tienen una posición vacante en los octaedros porque una de las tres posiciones octaédricas simétricamente independientes no está ocupada por cationes, resultando en un sitio vacante. La disposición de los grupos hidroxilo en la lámina octaédrica con respecto a esta vacante define la configuración cis o trans.

2. La mejor prueba de la eficacia sigue siendo in vivo

Experimentos in vitro han sido desarrollados como una forma efectiva para pre-detectar agentes de adsorción, antes de las pruebas en animales. Sin embargo, los resultados de la eficacia entre in vitro e in vivo pueden variar significativamente. Incluso entre bentonitas con alta eficacia de adsorción in vitro, hay diferencias en la eficacia in vivo, lo que indica que las pruebas in vitro por sí solas no son adecuadas para la evaluación de adsorbentes.

3. Sólo un tipo de bentonita está aprobada en la UE para la adsorción de micotoxinas

Actualmente la bentonita 1m 558 ha sido aprobada como una sustancia para la reducción de la contaminación de los alimentos por micotoxinas (aflatoxina B1) para cerdos, aves y rumiantes según la normativa de la UE en el registro de la UE para los aditivos para alimentos pecuarios. La aprobación se basa en la seguridad de utilizar el producto y la eficacia probada in vitro e in vivo de adsorción de aflatoxina.

Esta bentonita cumple con las siguientes características:
• Bentonita: ≥ 70% esmectita (montmorillonita dioctaédrica)
• <10% de ópalo y feldespato • <4% de cuarzo y calcita • Capacidad AfB 1 ligante (BC AfB1) por encima del 90%Al nivel actual de inclusión máxima recomendada de esta bentonita en la alimentación animal, la unión de vitaminas y minerales es insignificante.

ANCO knowledge: 3 things to know about bentonites

Bentonite can be applied in animal nutrition to adsorb mycotoxins and reduce mycotoxin bioavailability from contaminated feeds in the animal’s gut. It is a fine clay material mined from the earth. Most bentonites are formed by the alteration of volcanic ash in marine environments and occur as layers sandwiched between other types of rocks (as can be seen in the image above).

Bentonite is defined as a naturally occurring material that is composed predominantly of the clay mineral smectite. The Cation Exchange Capacity (CEC) and the specific surface area of smectites are considerable larger than other families of clays. Their absorption capacity is as much as 8 times greater than other clays.

However, there are a few things to know before applying bentonite to animal feed:
1. Not all bentonites are the same
2. Best proof of efficacy is still in vivo
3. Only one type of bentonite is EU approved for the adsorption of mycotoxins

1. Not all bentonites are the same

Bentonites are colloidal and plastic clay materials composed largely of montmorillonite (a species of dioctahedral smectite). The properties of bentonites can vary considerably depending on geological origin and any post-extraction modification. Their individual characteristics have a marked bearing on their economic use.

Despite the generic nomenclature of commercially-available bentonite, several physicochemical properties have been identified as having a possible correlation with adsorption of mycotoxins and might therefore be used to categorize the different available types.

These characteristics comprise:
• cation exchange capacity (CEC), exchangeable K+, Na+, Mg++ and Ca++,
• pH
• linear swelling,
• mineral fraction
• relative humidity
• d-spacing

Role of d-spacing for zearalenone adsorption

Adsorption to clays is not limited to the surface of the clay particles, but extends also to the interlayer space of the clay. This interlayer space, characterized by the d-spacing, can be determined with X-ray diffraction (XRD) and is restrictive for the formation of one or more adsorbent layers. This space can increase if the clay swells, thereby increasing the number of binding sites.
In vitro adsorption tests have shown that there is a positive correlation between zearalenone adsorption and d-spacing in commercially available products based on bentonite, i.e. large d-spacing was associated with higher % adsorption of zearalenone. (De Mil et al 2015). The d-spacing ranged from 9.2 to 21.5 (10-10 m) in 16 different products containing bentonite material, showing the large variation in material out there.

Difference between cis- and trans-bentonites for aflatoxin adsorption

Recent scientific data (Vekiru et al 2015) evaluating different types of bentonites for the in vitro adsorption efficacy relating to aflaxtoxin B1 has shown that most of the tested Ca- or Na-bentonites were effective. However, cis-bentonites were more effective than trans-bentonites.
Dioctahedral smectites that are found in bentonite have one vacant position in the octahedrons because one of the three symmetrically independent octahedral positions is not occupied by cations, resulting in a vacant site. The disposition of the hydroxyl groups in the octahedral sheet with respect to this vacancy defines the configuration cis- or trans-vacant.

2. Best proof of efficacy is still in vivo

In vitro experiments have been developed as a way to effectively pre-screen adsorption agents before testing in animals. However, results between in vitro and in vivo efficacy can vary significantly. Even among bentonites with high in vitro adsorption efficacy, there are differences in in vivo efficacy indicating that in vitro testing alone is not adequate for evaluation of adsorbents.

3. Only one type of bentonite is EU approved for the adsorption of mycotoxins

Currently 1m 558 bentonite has been approved as a substance for reduction of the contamination of feed by mycotoxins (aflatoxin B1) for pigs, poultry and ruminants according to EU regulation in the EU register for feed additives. The approval is based on safety of using the product and proven in vitro and in vivo adsorption efficacy of Aflatoxin.

This bentonite meets the following characteristics:
• Bentonite: ≥ 70 % smectite (dioctahedral montmorillonite)
• < 10 % opal and feldspar
• < 4 % quartz and calcite
• AfB 1-binding capacity (BC AfB1) above 90 %

At current recommended maximum inclusion level of this bentonite in animal feed, the binding of vitamins and minerals is insignificant.

Field trial with Anco FIT in antibiotic-free nursery pig diets

Applying Anco FIT in antibiotic-free nursery diets in a field trial under commercial conditions improved growth performance by >20% in the first 3 weeks and by 10% overall (Figure 1 below). Pig producers also reported a reduction in the amount of medication required for nursery pigs.

Impact of stress factors amplified with antibiotic-free diets

Weaning is a particularly stressful period for the pig and since the digestive system is not fully developed yet, the pig is also more susceptible to nutritional stress factors including less digestible nutrients and mycotoxins. This is particularly evident, when diets are fed antibiotic-free.

Importance of feed intake post-weaning

In the early stages post weaning, growth and development of the pig are driven by feed intake in a linear fashion. Scientific studies have shown that for every 0.1 kg extra feed per day during the first week post-weaning, body weight increases about 1.5 kg at the end of the fourth week post-weaning.

Weaning performance affects days to market

Feed intake in the first week post-weaning, also has consequences for later stages of growth. In studies conducted at Kansas State University, pigs that maintained or lost weight during the first week post-weaning required 10 extra days to reach market weight, compared with pigs that gained about 0.25 kg/day during the same period. Wilcock (2009) reported that for every 17g/day in the first twenty days post weaning, an increase of 1kg at slaughter can be expected.

Kansas state

Field trial, in nursery pigs Austria 2016

Commercial nursery pigs were fed antibiotic-free diets containing up to 36% corn, some wheat and some barley. Pigs did not receive medication. Average weaning weight was 9.3kg.

Nursery pigs fed Anco FIT in the diet gained considerably more weight compared to the control pigs, particularly in the first 22 days. This advantage was maintained at 41d weight (Figure 1 below).

Read more about pig production in Austria: here.

Video Link: What matters to Austrian pig farmers feeding Anco FIT

nursery pigs performance

ANCO knowledge: What matters to quality pork producers

Pork producers certified by AMA (Agrarmarkt Austria Marketing) produce pork of the highest quality standard in Austria (see more info below). What really matters to them in pig production is high performance, quality and flexibility in production, whilst feeding antibiotic-free diets and meeting the top demands on animal production from consumers in Austria.

3 most wanted characteristics in farmers by the public

1. 85% treat animals responsibly
2. 82% treat the environment responsibly
3. 77% produce food of high quality
(survey of 1000 people, Bauernbund 2015)

What does the AMA seal approval stand for?

AMA_gutesiegel_logo

Food products that carry the AMA (Agrarmarkt Austria Marketing) seal of approval
• Meet the highest quality standards.
• Transparency: It guarantees that foodstuffs can be traced to their source.
• Farmers, processing plants and retailers certified by AMA conform to standards, which are stricter than required by law and are monitored by independent testing centers.
• Animals raised and slaughtered in Austria.
• Antibiotics are only allowed for treatment and only with prescription from vets. If animals are treated with antibiotics withdrawal times are twice as long as what is required by law.
• The majority of feed comes from home grown cereals. Any feed supplements need to be bought from AMA certified feed manufacturers.

Number of AMA certified pig producers

Currently there are 1800 pig producers in Austria, that are producing according to AMA standards. The total number of pig producers in Austria is around 30 000.

Agriculture and pig production in Austria

The agricultural sector in Austria is shaped by small family farms.

The average farm in Austria has:
• 71 pigs
• an average utilized agricultural area (UAA) in ha per farm of 19.3 ha
• 14% have more than 50 ha.
• 34% of arable land is producing feed grain
(Federal Institute of Agricultural Economics 2011).

Out of around 132653 farms in Austria:
• 56% are part-time farmers
• 17% are organic farmers
• 80% are livestock farmers
• 23% are pig farmers

The current economic value of pig production in Austria is 860 Mio Euro (Bauernbund 2015).