Organic acids properties associated with their Carboxyl group –COOH groupextensively used for decades in feed preservation, protecting feed from microbial as well as fungal destruction. Thus, it may increase the preservation effect of fermented feed. Withdrawal of antibiotics from poultry feeds has generated the need for alternatives that would affect improvement of healthy production traits of broiler chickens and safety for human consuming poultry products. Organic acids such as formic and propionic acids are particularly effective for this purpose and have been used extensively from past 25 years in swine production mostly for feed preservation.
In General, Organic acids are any carboxylic acid including fatty acid& amino acid. Organic acids categorized as weak acid & do not separate completely in water. The formic acid in breeder diet reduces the contamination of tray liners as well some hatchery waste with S. enteritidis. The diet supplemented with lactic acid was found to increase the body weight. The blend of acids is preferred to individual acid in obtaining the desired antimicrobial effect and acidification of diets with weak organic acids such as formic, fumaric, propionic, lactic and sorbic have been reported to improve digestibility of protein, Ca, P, Mg, Zn and served as substrate in the intermediary metabolism. The blend of formic and propionic acids found to be effective in preventing intestinal colonization with Salmonella spp. from naturally or artificially contaminated feed. Relative studies of organic acids showed that the inhibiting effect of the acids was more evident in stomach contents than in content from the small intestine, probably due to the lower pH in the stomach content.
Organic acids play important role as a feed supplement in poultry has a valuable effect on the overall performance of the broiler as well as layer birds. The individual effect of organic acid variable and depends upon several factors. Likewise, different pathogenic bacteria respond variably to various similar organic acids. Organic acids have direct effect on different GIT parameters that may improve the nutrient absorption and digestibility. Effect of bactericidal organic acids is in the following order:
Benzoic acid (C6H5COOH)>fumaric acid (HO2CCH=CHCO2H)> lactic acid (C3H6O3)> butyric acid (C4H8O2)> formic acid (CH2O2)> propionic acid (C3H6O2).
Feed Acidifiers showed acidic nature comprised in feeds in order to lower the isoelectric point (pI) of the feed, gut, and microbial cytoplasm thereby inhibiting the growth of pathogenic intestinal microflora. Thus, inhibition reduces the micro flora competitively inhibition for the host nutrients and results in better growth performance of the chicken. They also act as mold inhibitors. Organic acids ions showed antimicrobial effect influence bacterial population is in the upper intestinal tract leads to beneficial effects.
Mode of action of Organic acids
Acidifiers with short chain fatty acids, acetate, propionate and butyrate have contributed expressively to the profitability in poultry and provide people with health and nutritious poultry products.
Un-dissociated form of acid RCOOH could penetrate the bacterial cell wall. Once in the bacterial cell, the higher pH of cytoplasm cause dissociation of the acids, and the resulting reduction in pH due to the release of H+ disrupt the enzymatic reactions &nutrient transport system. This influence destruction of the cytoplasm, as well growth of the bacteria is inhibited. Organic acid ions have capability to attacks on bacteria genome results in its death.
Though there are certain challenges like palatability of the feed, corrosion of the equipment, buffering capacity of dietary ingredients, bacterial resistance due to long term exposure etc. which are manageable with certain preventive measures, the acidifiers are being used due to the larger benefits envisaged. Some of the advantages are listed below
Advantages of feed acidifiers
Feed Acidifiers feeding in poultry
Table: Organic acids impacts in Poultry
|1.||Fumaric acid||Improvement in weight gain of
|Increase in dressing percentage in female broilers
& reduction in abdominal fat for males.
|3.||Malic acid||Increase in body weight gain.|
|4.||Sorbic acid||Improves feed efficiency ratio.|
|5.||Tartaric acid||Increase in weight gain.|
|6.||Lactic acid||Feed to gain ratio and Body weight gain is improved.|
|7.||Formic acid||Reduction of caecal pI and bactericidal effect on
|8.||Benzoic acid||Positive influence on growth.|
|9.||Butyric acid||Maintain the beneficial micro flora. Increase the
Proliferation and maturation of intestinal cells.