The natural biopolymer called chitosan is presented as an effective alternative to antibiotic growth promoters in ruminant diets, according to research conducted by researchers from the Basque technology center Neiker-Tecnalia. The presence of these antibiotics as feed additives in ruminants is banned in the European Union since 2006, because its use is associated with the development of microbial resistance to antibiotics.
The main problem is that the ban is estimated that production costs of farms have increased between 3.5% and 5%, besides increasing the environmental problems caused by increased holdings of methane gas emission . Thus, Neiker-Tecnalia research has aimed at finding alternatives to antibiotics antimicrobial growth promoters.
Chitosan proved to be an attractive alternative because, in addition to its antimicrobial activity contrasted, has certain advantages because it is a composite biodegradable, biocompatible, renewable and non-toxic. This allows antimicrobial action hypothesize that chitosan affects specifically some of the microorganisms in the rumen, the largest of the forestomachs of ruminants, and thus produced a beneficial effect on rumen digestion. This effect is similar to that produced by monensin, an antibiotic most widely used growth promoter in the diet of ruminants before prohibition.
The results are very promising research on the potential of chitosan to manipulate rumen fermentation, with the aim of improving feed efficiency and promote the use of nutrients for ruminants. If these improvements are converted into productive and commercially competitive, chitosan can be an effective alternative to antibiotic growth promoters in ruminant diets.
Essays in vitro
Throughout the investigation raised a series of tests to determine the effect of chitosan on rumen fermentation. Initially, tests were performed in vitro simulation of rumen fermentation to determine the effect of different types of chitosan on rumen fermentation, and the influence of diet, dose and incubation time on such effects.
In the first tests in vitro made using a technique of batch cultures. In this technique a particular food is incubated with an inoculum from the rumen of sheep, under conditions of pH and temperature that simulate rumen own. In these trials it was found that the modified chitosan rumen fermentation process in a way that could be beneficial to the animal, for example, increases the production of propionic acid during the fermentation of up to 95%. It was also noted that these effects were more important or modifications as the degree of deacetylation of chitosan molecule increased and as the ration or diet contained higher proportion of concentrate.
In the second test in vitro made was used in the Rumen Simulation Technique or RUSITEC. This technique differs from earlier in this case semicontinuous fermenters are used where there is a recycling of the culture medium. Therefore, to maintain a stable rumen microorganisms growing longer for larger studies to long term, to explore the persistence over time of effects seen with the prior art, and to rule out a possible adaptive effect of microorganisms rumen to chitosan. In these studies we observed that the effect of chitosan on rumen fermentation persisted in the incubation time, with what might be ruling out an adaptive process of rumen microorganisms to the compound.
Thus, in trials in vitro results were very promising, based on improved energy efficiency of the fermentation process in rumen fermentations led to the production of propionic acid and decreased production of methane during this process up to 50%.
In animal tests showed that the modulatory effect observed rumen fermentation in vitro is also observed when the chitosan is administered directly to animals, resulting in improvements in energy eficiecia of fermentation in the rumen was affected without the digestibility of the ration.
|Category: Chemistry||Tags: antibiotics, deacetylation, microbial resistance, microorganisms, ruminant diets|