Is there any effect of organic acids on pepsin activity which will ultimately improve protein digestion.
Dear Dr. Shyam, Pepsins are the principle proteases in gastric secretion. The activation of pepsinogen and subsequently of pepsin is organic acids dependent. Optimal activity of pepsins is at pH 1.8 to 3.5. They are inactivated at a pH of 5. Since the proteases are responsible for the digestion of proteins it has been shown that acidification with organic acids can improve protein digestibility, for instance from 86% up to 90% (apparent digestibilty improvement after formic acid use).
Dear Dr.Luckstadt Can you pls elaborate the mode of action organic acids in shrimp digestion. Regards T.Gnanamani
Dear Mr. Gnanamani, we have seen promising effects in shrimp (L. vannamei) with the use of dietary organic acid salts, in particular potassium diformate, especially on weight gain, survival rate and FCR - thus productivity is significantly enhanced, as demonstrated last week at the Asian Fisheries and Aquaculture Forum in Shanghai. The reduction of mortality is clearly a results of the inhibition of pathogenic bacteria, like Vibrio. The improvement of FCR might be explained by improved digestibility. I may speculate here on impacts on the hepato-pancreas after altering the pH in the neutral GI-tract of the shrimp.
Dear Dr. Luckstadt: are this organic acids recommended on pet foods? which are mainly recommended and what are the effects on palatability?
Dear Mr. Arancibia, no, formic acid or formate based additives are not recommended for use in pet food. They can be safely used organic acids in swine, poultry, fish, shrimp and calve. In swine a spanish study recently proved that potassium diformate is increasing palatability of diets. There were significant effects on improved feed preference
what is the mode of action for formic organic acids in damging of salmonella ?
Organic acids, like formic acids, have to ways in inhibiting the growth of gram-negative bacteria, like Salmonella, E.coli, Campylobacter etc. One is via a pH-decrease of the environment in which the bacteria strives. Bacteria have a certain pH-optima in which they can grow. For Salmonella the minimum pH in which it can still grow may be around 4.5; but the optimum is certainly nearer to neutral. So even if you don't reach pH-levels below 4.5 you are able to increase the generation time (in other words make the Salmonella less quick in reproducing) of the bacteria. The second way of inhibiting the bacteria is by penetrating its cell membrane (works only fro gram-negative bacteria). The undisscociated part of the acid is able to penetrate this membrane and can release H+ ions into cytoplasm of the cell. This will lead to a counter-reaction of the cell (pumping H+ ions out with the use of energy. This energy expenditure will weaken the bacteria and may lead ultimatively to cell death. Formic acid in particulra has shown in several MIC-studies that it is among the strongest acids to stop growth of for instance Salmonella!
Dear Mr. Tran, you can eitehr use titration methods (ISO 2114) to measure the amount of formic organic acids - and based on that calculate the amount of diformate content (from the CoA of a diformate you would know the amount of formic acid in a given diformate product). This method can be carried out by nearly all labs world-wide. If you need to measure diformate in a matrix, like compound feed, you would need to do an ion chromatography analysis.
Dear Dr. Luckstadt. I appreciated the info you brought about regarding diformate and how it can be measured. Is it also possible for other formic salts like calcium formate? How does the two compares both for activies and effectivity especially for swine? How would we know the adequete dosage or volume to be used for both organic acids? Thanks in advance. I had been using organic acids as per manufacturer's prescription but am i using it right or am i maximizing the suppose benefit of such products? Respectfully, Rodel Villaraza
Dear Dr.Christian, I really appreciate your prompt reply in this forum on organic acids. Since pH of GIT of poultry at foregut & hindgut varies considerably I doubt a single organic acid will give the desired level of pH 4.5-5 through out the GIT of poultry. In our experience product containing right combination of organic acids having different pKa value has showed good activities to inhibit bacterial growth as well as helped in digestion of feed. Would you recommend single organic acid or combination of selected organic acids as an acidifier for poultry? Thanks !
Dear Dr. Ettiqi, thank you for the nice comments on using lactic acid in rohu. As I am always interested to see new results on the use of organic acids in fish, which I think is one of the upcoming additives in current aquaculture, would you mind sending me some data, if published? You may contact me under email@example.com Thanks!
Dear Dr.Christian, Thanks once again ! There is no iota of doubt that lowering pH & ability to inter into cell membrane to release H+ ion into cytoplasm of gram negative bacteria should be the key trait for selecting organic acids to prepare acidifiers. Shall we select those organic acids/salts in combination which are much capable of disassociating within the bacterial cytoplasm, increasing the cellular hydrogen ion concentration so that product could be able to work in foregut as well as hindgut? Please also inform us required dose of Diformate to achieve 85% activities at hindgut of broilers, layers & breeders. Your response is solicited. Regards, G.K.Dahal
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