TOLSA NEWSLETTER FEED

Transcription

1 SILICATES AS FEED ADDITIVES: A REVIEW OF EXAL PROPERTIES ON ANIMAL PERFORMANCE INTRODUCTION For many years, the use of silicates as binders of compound feeds has been prove in the animal nutrition sector. Among silicates, sepiolite plays a fundamental role due to its peculiar properties, and thus, it is not rare that it is a common mineral used in the feed industry. In 1989, EXAL was registered in the European Union as a sepiolite-based technological additive (E-562) that can be used on all animal species. This means EXAL helps bringing into the human diet good quality animal protein. During the last thirty years, researchers worldwide have tried to evaluate the importance of these clays in the manufacture of animal feed and premixes. In particular EXAL,not only as a technological additive, but also as a nutritional and environmental additive, has gone through many different tests over the years. In fact, there are many bibliographical studies which show that EXAL is able to provide an added nutritional value to feed, by influencing the gastrointestinal metabolism and physiology, and consequently, improving animal performance. EXAL PROPERTIES IN ANIMAL FEED 2. 1 Technological effect: EXAL has been widely used as a binder agent, especially for pelleted feed. The use of EXAL allows to visibly improve the pellet quality in terms of durability and pellet fragmentation (Castaing 1989, 1994). EXAL s power of agglomerating substances comes from its great capacity to absorb water; this helps avoiding feed caking caused by excessive moisture, and consequently, the obstruction of pelleting machines matrixes. Due to its high absorption capacity, the inclusion of EXAL in the animal feed formula also allows high durability to be obtained even in animal feeds with a very high fat content while preserving moisture. The addition of EXAL at a 2% rate makes it possible to increase the fat percentage added in the formula, improving the energetic concentration of the feed without altering the pellet quality (Angulo et al., 1997). This has a positive impact on granulator productivity, reducing energy costs in production and increasing profitability. To provide the optimum advantages as a binder agent, EXAL will have to be combined with an increase of the water used during the pellet manufacturing. To calculate the level of water needed, it is very important to take into account the initial moisture of the raw materials and the loss or gain of moisture that they can suffer through the course of the pelleting process.

2 EXAL s carrier properties favours feed particles to go smoothly through the different machines involved in the manufacturing process. EXAL reduces the friction between particles, making it possible to form the pellets at lower temperatures and with less pressure. This has a double positive effect: in the one hand, it helps avoiding the negative effects from a too high temperature on the nutritional properties of the feed; while in the other, the carrier effect reduces the energy needed during the compression process, improving economic costs (Alvarez & Pérez, 1983). EXAL has a preservative impact as well thanks to its moisture levelling properties. Its capacity to prevent the development of undesirable microbiological processes during the storage of raw materials while preserving the feed nutritional value in a natural way must be enhanced. To that end, the addition of EXAL allows a better feed distribution in the production silo, without forming air layers, and thanks to its extraordinary absorbent capacity it prevents the fungi development. Why is EXAL recommended for pellet manufacturing? Better pellet quality durability Better moisture regulation of the pellet Increase the production of the pellet machine Reduction of energy costs in the pelletizing process Reduction in dust formation during the manufacturing process Better capacity of feed preservation Less dust when handling during the feed distribution 2.2 Nutritional effect: Along other positive effects on the feed manufacturing, the interest for EXAL as a nutritional additive increased when preliminary results were obtained from its positive effect on the productive parameters, and because of its action on the digestion and metabolism (Escribano, 2004). Many studies have been carried out to demonstrate the nutritional benefits of EXAL in the animals: EXAL increases Final Weight and Dairy Weight Gain (DWG), while reducing Intake of feed and Feed Conversion Ratio (FCR) of the animals. In general, it can be said that these improvements are mainly caused by the increase of organic matter, fat, protein and metabolizable energy (ME) digestibility.

3 ORGANIC MATTER FAT PROTEIN METABOLIZABLE ENERGY Trial n. Control EXAL Control EXAL Control EXAL Control EXAL Ref Ouhida Ouhida Magnin and Corniaux Ouhida Ouhida Ouhida France France France IRTA IRTA Brufau IRTA Brufau 2000 Average One of EXAL s most interesting actions is its effect on the digestive physiology of broilers, and more particularly on the gut retention time of nutrients. The results of many studies such as Tortuero (1992), Wisemann (1996) or Escribano (2004), prove the slowdown of the gut retention time when using EXAL, due to its colloidal properties (Santarén, 1996). The rheological properties of EXAL determine its water absorption and gel formation capacity, which regulates the slowdown of the gut retention time of nutrients through the digestive tube. This favours as well the digestibility of nutritional substances and increases absorption of some vitamins and minerals (Tortuero 1981; Tortuero & Diez, 1981). 2.3 Environmental effect: Another significant aspect of EXAL is its quality as an environmental additive. There are many studies that endorse EXAL s capacity to reduce the faeces ammonia emissions, and consequently, the improvement of the farms atmosphere quality and the environment. The decrease in the ammonia content from the faeces is mainly due to the reduction of urinary nitrogen excretions, as resulted from the trials carried out on the nitrogen balance in broilers (De la Fuente et al., 1994) and swine (Parisini et al., 1993; Eeckhout 1995; Castaing & Noblet, 1995; Cahn et al., 1996). Determination of the fecal nitrogen of broilers fed with diets containing higher amounts of maize and sepiolite EXAL.(De la Fuente et al., 1994). N in faeces, % Maize Wheat EXAL, % 2 Average (-8%) ** Average ** 4.97 (-6.5%) *ASE = Average Standard Error 0,07; n=12 ; **P < 0,0

4 Ammonia (NH3) is present in farm installations at very high ratios, although it depends on the species, temperature and moisture level, airing systems, animal volume and kind of litter. Inappropriate litters can produce huge ammonia emissions putting animals health and welfare at risk (legs damages and respiratory pathologies). They can even fully damage the ecosystem, contaminating the atmosphere and the surface and underground waters. Study of Broiler development and litter quality in diets with 2% EXAL based in wheat (41-days animals): Control Exal P Mortality, % Slaughter, % Ingested feed Body weight, g FCR based in bodyweight Litter quality <.001 Leg injuries, % The use of EXAL in the formula helps significantly the improvement of the litters quality due to its absorption capacity and interpolation of liquids and gas, which reduce the ammonia and emissions of mercaptans from droppings. As a result, litters become drier and less stinking. Another use of EXAL is as a coadyuvant agent during diarrheic symptoms, since it can absorb a great quantity of water excessively accumulated in the digestive tube during these processes. Thus, it is very important to improve the handling of the atmosphere conditions in which animal live, keeping litters drier and cleaner while allowing the production of high-quality products such as eggs. Effect of the addition of EXAL in diets opposite diarrhoea. J. Ani. Sci. Pérez & Gasa Effect of the addition of Exal 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Control C + 2% EXAL Wheat & Barley Wheat & Barley + 2% EXAL CMC CMC + 2% EXAL NO Moderated Heavily

5 Effect of the addition of EXAL in the diet on the egg quality of laying hens. Field trials, 2004 Dirty Eggs (%) 3,00% 2,00% 1,00% 0,00% 2,62% Control 1,34% Exal Why is it advisable to use EXAL for bedding? Moisture control Control of ammonia and unpleasant odors Control of microorganisms Simple handling and use as a fertilizer once the breeding is finished or it requires to be removed or replaced Not harmful for the animal skin They hinder claw lesions and don t cause breathing problems Biosecurity derived from their chemical inertia Absence of microbial contamination CONCLUSIONS The results obtained from many studies carried out with regard to the properties of this particular mineral show the extraordinary versatility of EXAL in both zootechnics and animal nutrition fields. EXAL is a mineral additive, 100% natural, which does not leave residues in the animal production. Thus, it is safe from the nutritional point of view, and has the capacity to determine an increase of production, in terms of costs reduction and better productive rates, without forgetting the respect for animal welfare and the environment. PROPERTY USES ADVANTAGES Water and fat absorption Pelleting Health Animal well-being Better feed quality Less diarrhea Dry bed Chemical inertia Feed and premix No interferences Rheology Increase time for digestion Improved digestibility Particle size and density Feed and premix Homogeneity Flow ability