IMPROVED MILBOND-TX® SAFETY STUDY DEMONSTRATING NO BUFFERING CAPACITY
In the young pig at weaning, as well as in other animals, it is desirable to maintain a low stomach pH. A pH of 4.0 or lower activates the enzyme, pepsin, which is required for the initiation of protein digestion associated with the unfolding of the natural protein structure in feed ingredients of plant and animal origin. A low pH also promotes the release of minerals and some vitamins which are bound to proteins. Mineral dissociation (solubilization) from compounds such as CaCO3, FeSO4 and MgCO3 occurs at a low pH and allows Ca, Fe, and Mg, as well as other minerals, to be available for absorption. The enzyme, phytase, which liberates organically bound P for absorption, is most active at a low pH. Of equal importance, a low pH promotes overall animal health by inhibiting the growth of pathogenic bacteria such as Salmonella, Streptococci, E. coli, Staphylococcus and Pseudomonas. The ideal pH promoting growth of these pathogens is specific for each pathogen, but in the digestive tract a higher pH encourages multiplication. The ideal pH range for these bacteria is between 6 and 8, however, at a pH of 4.0 and below these pathogens do not proliferate. In order to maintain a low pH adequate hydrochloric acid (HCL) must be produced at a rapid rate by specialized stomach cells. This is especially true following a meal when the stomach pH increases due to the buffering capacity of various feedstuffs used in diet formulation. Unfortunately, the young pig’s stomach is not fully developed and has a limited ability to produce HCL. Because of this, any feed additive that would have a tendency to raise the pH by neutralizing the HCL would not be a desirable component of the feed. This would also be of concern for the newly hatched chick since its digestive tract is also immature for several weeks following hatch.
In over 30 in-vitro and in-vivo studies conducted during the past 25 years, Improved Milbond-TX® (IMTX) has been tested for its safety and efficacy. A recent in-vitro study conducted in the laboratory of Dr. John Driver in the Department of Animal Sciences at the University of Florida provided further evidence showing IMTX, when used at the recommended dietary concentration of 0.25% (2.5 g/kg diet), is inert and has no ability to neutralize a solution of HCL at a pH of either 2.0 or 5.0. This finding has been of extreme interest to swine producers using IMTX in their baby pig diets. The following describes the in-vitro experiment.
At weaning, a pig will normally weigh between 5 and 6.5 kilograms and will be consuming between 225-325 grams of feed each day. Soon after being weaned feed consumption increases quickly. In order to determine the amount of IMTX to use in the experiment, the total amount in 225 gm of feed was used in the calculation. This amounted to 0.56 gm of IMTX (225 gm X 0.0025 = 0.56 gm). Also, the amount of IMTX in one pound of feed (454 grams) when used at the recommended concentration of 0.25% was chosen instead of 325 grams in order to give IMTX more opportunity to buffer the HCL solution, if indeed, it had any buffering capacity. This amounted to 1.1 grams of IMTX (454 gm X 0.0025 = 1.1 gm) which would be added to the un-buffered solutions of HCL already containing the 0.56 grams of IMTX. In so doing, this extra concentration of IMTX added to the solution already containing 0.56 grams of IMTX would provide the presence of even more IMTX to buffer the HCL solution. The two HCL solutions with a pH of approximately 2.0 and 5.0 were made by adding HCL to 200 ml of deionized water and checked with a pH meter. The above amounts of IMTX were added to each HCL solution and following 30 seconds of mild stirring the pH was immediately recorded.
(Note: Prior to adding the first quantity of IMTX to the HCL solutions with a pH of 2.0 and 5.0, the pH of each solution was checked and recorded as 2.05 and 4.98, respectively).
Low pH solution: Thirty seconds after adding 0.56 grams of IMTX to the HCL solution with a pH of 2.05 the pH was 2.06. Thirty seconds after adding the 1.1 grams of IMTX to this solution the pH was 2.10. So, after adding a total of 1.66 grams of IMTX to this HCL solution with an initial pH of 2.05 the pH only increased by 0.05 pH units. Thus, the 1.66 grams of IMTX added to the HCL solution reflected a dietary IMTX concentration of 0.36% instead of the recommended 0.25%.
High pH solution: Thirty seconds after adding 0.56 grams of IMTX to the HCL solution with a pH of 4.98 the pH was 5.01. Thirty seconds after adding the 1.1 grams of IMTX to this solution the pH was 5.05. So, after adding a total of 1.66 grams of IMTX to this HCL solution with an initial pH of 4.98 the pH only increased by 0.07 units. As above, this represented a dietary IMTX concentration of 0.36% instead of the recommended 0.25%.
These data collected in this experiment provide conclusive evidence that when IMTX is added to a weaned pig’s diet at the recommended dietary concentration would not be expected to have any measurable negative effect on the pH of the fluid contents in the stomach. This would be true even if IMTX was accidently added to a diet at a slightly higher quantity than the recommended concentration of 0.25%. Furthermore, it must be kept in mind that pigs consume their feed all throughout the day and in-so-doing would not consume at any one feeding the total amount of IMTX used in this in-vitro experiment. Therefore, adding IMTX at the recommended dietary concentration of 0.25% is safe and has no buffering capacity which would tend to neutralize the pH in the stomach of a pig or other animal.
Note: This in-vitro experiment is unpublished and was conducted in order to answer the question from swine producers about the buffering capacity of IMTX, especially in weaned pigs. The information presented in this issue of Milwhite’s Journal was compiled by Dr. Orlando Osuna, Director of Health Science at Milwhite, Inc. and Dr. Richard Miles, Professor Emeritus, University of Florida, Gainesville, FL, USA.