the use of organic acids in animal feed
Ideally, the positive effect of acidifier is to control the balance of gastrointestinal microflora, stimulating the performance of digestive enzymes, improve feed digestibility and production performance of poultry. Optimization of the digestive tract functions as a gate to the absorption of food nutrients need to be maintained in order to obtain the maximum productivity of chickens. Poultry feed are digested, absorbed and metabolized in the digestive tract. Some components greatly affect the performance of the digestive tract as digestive enzymes, bile acids, pH, feed flow rate, the balance of microflora and so on. These changes will affect the structural components of the digestive tract and the digestibility of feed. Antibiotics as an effort to maintain the condition of the digestive tract by controlling the balance of microflora and stimulate the chemical in the digestive tract of poultry.
Use of antibiotics in animal feed has been used since 1946 with the aim of improving livestock productivity and health status. In birds, antibiotics are used in order to improve the digestibility of feed, growth and egg production, improve feed conversion, mortality, and keep pressing health conditions. But along with the prohibition of the use of antibiotics as a driver of growth in several countries around the world need to find a solution to mensubsitusi use of antibiotics in poultry feed. Probiotics, prebiotics, organic acids, essential oils, plant extracts and enzymes as feed additives have been used to substitute the use of antibiotics. In this article will explain the use of organic acids as feed additives to maintain the condition of poultry digestive tract.
The term organic acid is a chemical compound from the class of fatty acids that have a pH below 7 or acidic. But in terms of the fodder over again dispesifikkan function that aims to use organic acid food preservative (feed preservation) and control the pH of the digestive tract (acidifier). In this article will discuss the use of an organic acid as acidifier for poultry. Acidifier term is still contradictory among investigators. Some researchers termed the acidifier is used to lower the pH of the digestive tract, but on the other hand, the researchers concluded that the acidifier is used to control the pH in the digestive tract as if in a condition where the digestive tract is the optimum pH, acidifier will not work to lower the pH because it will cause the atmosphere pH is too acidic and cause indigestion and intestinal microflora imbalance.
There are two types of commercially available organic acid that is a single organic acid and organic acid complexes. Each product has a similar function, namely to maintain the condition of the digestive tract and increase the productivity of poultry. But the products sold are not purely organic acids but has been mixed with salts to adjust the pH of the digestive tract. The use of organic acid cocktail alone or in the feed will show different results depending on the type of organic acid used, the origin of organic acids, organic acids given amount, composition and condition of livestock feed (Soltan, 2008). In general, the role of acidifier in poultry feed is shown in Table 1.
Acidifier role in controlling the pH of the digestive tract
Acidifier create acidic conditions in the small intestine to produce ideal conditions for growth of Lactobacillus and other non-pathogenic microbes and inhibit the development of Escherichia coli, Salmonella and other pathogenic microbes. Acidifier performance in the small intestine will support the activities and functions of digestive enzymes, stimulate feed intake, reduced ammonia production and yield of microbial metabolites that inhibit growth and enhance nutrient absorption of feed substances.
The addition of acidifier in the feed also lowers the pH in the feed as described by Soltan (2008). Abdel-Fattah et al. (2008) conducted a study to compare three types of acidifier namely acetic acid, citric acid and lactic acid were added in broiler feed. The results showed that the addition of 3% or 3% acetic acid citric acid or 1.5% lactic acid in the diet can lower the pH of the gizzard, duodenum, and ileum jejenum broiler although not statistically significantly different. Control of pH of the digestive tract is essential to maintain balance microflora and digestive enzyme performance.
Acidifier role in improving metabolic processes in the digestive tract
Acidifier will also affect the pH of the stomach. With a decrease in gastric pH will increase the conversion of pepsinogen to pepsin an enzyme that serves to increase the rate of absorption of protein, amino acids and minerals. Digestibility of feed will increase with the addition of organic acids in the diet. Hernandez et al. (2006) reported that the addition of formic acid (10 g / kg of feed) in the feed to increase digestibility of dry matter (in the ileal digestibility) in broiler chickens. Bahnas (2009) reported similar results using malic acid. Deepa et al. (2011) reported that broilers fed citric acid containing phosphorus showed increased uptake in the small intestine compared with chickens fed does not contain citric acid. But there is no mechanism of citric acid as an acidifier why play a role in increasing the absorption of phosphorus as described in the study Boling et al. (2001). Initial allegations raised in chicken feed that contains phosphorus which binds with phytic acid, a substance antinutrisi in vegetable feed ingredients that cause phosphorus and some of the nutrients difficult to absorb the small intestine. Ability of citric acid in the binding of phosphorus and phytic acid weakens the bond between a nutrient and phytic acid is thought to cause more soluble and less stable so that phosphorus is bound to phytic acid will be easily absorbed by the intestines. Cosgrove (1980) suspected that citric acid plays a role in lowering the pH of the small intestine and inhibits the formation of insoluble phytate salts are hydrolyzed by the enzyme are resistant to endogenous phytase in the small intestine.