Page 15 - Australian Pork Newspaper
P. 15

How acidifiers improve gut health in pigs
TO see organic acids or simply acidifiers being used as feed additives to replace antibiotic growth promotors is common now.
high by the buffering ca- pacity of the diet.
This means organic acids promote the proliferation of beneficial bacteria which are acid-tolerant such as the lactobacillus sp and bifidobacterium sp, creating the preferred microbiota-balanced or eubiotic state in the gut.
Also observed was that SCFA in pigs increased the relative mRNA ex- pressions of intestinal de- velopment-related genes, including IGF-1, IGF-IR, GLP-2 and GLP-2R, in- dicating the benefits of SCFA on gut morphology and development.
– while promoting the pro- liferation of beneficial bac- teria tolerant to lower pH.
otal role in the intestinal and general energy me- tabolism.
acid as an energy source, with an efficiency close to that of glucose.
Acidifiers play an impor- tant role in pig gut health in many ways.
Thus, the pH value in the stomach may stay high at usually pH 4-5 after feeding leading to sub- optimal protein digestion and unfavourable pH for killing pathogens.
In this view, organic acids can be an optimal tool to control the dys- biosis characterised by coliforms overgrowth and lactobacilli depression, typical of weaning time in pigs.
Butyric acid is almost completely oxidised within the mucosa, serving as preferred energy source for the colonocytes, whereas propionic acid is collected by the liver where it is converted into glucose, and acetic acid is instead used by peripheral tissues.
The researchers also gave an overview of the various applications of acidifiers in animal nu- trition as highlighted in Figure 1.
Two recent studies published in 2020 in the Journal of Animal Physi- ology and Animal Nutri- tion and Animals Journal give an overview of key benefits of acidifiers in pig gut health.
Besides poor production of HCL, piglets lack suf- ficient lactic acid from lac- tose fermentation.
Based on the environ- mental pH and pKa values, organic acids in their un- dissociated form can dif- fuse across the bacterial cell membrane and disso- ciate inside the cell, re- leasing H+ ions and de- creasing intracellular pH.
Taking an example, butyric acid was seen to promote intestinal epi- thelial integrity as meas- ured through its effects on increasing the relative mRNA expression of tight junction – offering an in- testinal barrier function.
Factors influencing ef- ficacy
The research focussed on the benefits of organic acids on pig gut health as exerted through different modes of action in the feed and along the gastrointes- tinal tract in pigs.
High gastric pH impairs pepsin activation and function – optimal under pH 2 to 3.5 – reducing the efficiency of protein digestion.
This inhibits bacterial replication and growth, leading to bactericidal ef- fects.
Modulation of micro- flora
The researchers also found that besides in- dividual organic acids, blends of organic acids in- cluding SCFA, MCFA and acids salts increased the levels of acetic, propionic and butyric acid produced by microbial fermentation of carbohydrates in the large intestine.
Coating, as an example, ensures the slow release of acids throughout the GIT and curbs the effect of odour.
The modes of action in- clude reduction of pH and feed buffering capacity, antimicrobial actions, beneficial modulation of microflora, the provision of energy and factors in- fluencing efficacy.
Improved protein diges- tion means a healthier gut and undigested fractions that could act as substrate for pathogenic bacterial strains are reduced.
The efficacy of organic acids varies depending on the target organism.
The researchers further explained how organic acids modulate intestinal fermentation patterns.
In addition, the re- searchers point out that pigs can utilise fumaric
The researchers further highlighted that acidifiers improve protein digestion by reducing the buffering capacity of feed.
SCFA reduce the pH and promote the proliferation of beneficial bacteria, thus offering a probiotic effect in the colon.
Sorbic acid added to weaning piglets increases growth performance through the modulation of lipid metabolism and the enhancement of insulin- like growth factor system, particularly relevant for the GIT development.
Several factors influence the efficacy of acidifiers: physical and chemical form of acid, salt, coated or uncoated, odour and taste, solubility, pKa value, minimum inhibitory con- centration, site of action, dietary composition and feed buffering capacity.
Organic acids can be classified into three main functional categories: short chain fatty acids, medium chain fatty acids and tricarboxylic acids.
This indicated a shift in the composition of intes- tinal flora and a modula- tion of microbial fermen- tations with more nutrients or metabolites such as ac- etate available to the host.
Provision of energy
The common MCFA are lauric, capric, caprylic and caproic, while for SCFAs they are acetic, propionic and butyric acids, and citric, malic and fumaric for TCAs.
On the other hand, high pH increases the rate of gastric emptying, reducing the digestion time in the stomach.
The lipophilic nature of MCFA allows them to have a stronger antibacte- rial activity against gram- positive species, whereas the presence of lipopoly- saccharide in the gram- negative cell wall confers resistance to these species.
Based on the antimi- crobial mode of action, organic acids can inhibit the growth of undesired pH-sensitive microorgan- isms – enterobacteriaceae
Organic acids can have a metabolic role by im- proving the intestinal mu- cosa trophism and modu- lating general metabolism, particularly for SCFA.
Other than these cate- gories, few organic acids such as benzoic, sorbic and lactic acid are widely used in food and feed preserva- tion.
For example, citric acid increases calcium and phosphorus absorption through chelating calcium – this makes the phytate structure less stable and more accessible to phytase action.
The benefits of salts are less odour, easy handling during feed manufacture, less corrosive and high sol- ubility in water compared to free acids.
Antimicrobial action
Explaining feed buff- ering capacity
Though the antimicro- bial activity differs be- tween organic acids, by influencing the pH most organic acids inhibit the growth of pathogenic bac- teria.
The researchers stress the antimicrobial action of organic acids exerted through reduction of pH of the feed – reducing the risk of microbial contami- nation to the animal – and by direct growth inhibition of specific pathogenic bac- teria such as salmonella.
What the researchers found was that the efficacy of acids against the coli- form bacteria follows this order: benzoic > fumaric > lactic > butyric > formic > propionic acid.
The addition of organic acids to piglet diets is im- portant since piglets lack the capacity to acidify their stomach content by hydrochloric acid and gas- tric pH of piglets is kept
The proliferation of most pH sensitive bacteria such as e coli, salmonella and c perfringens is minimised below pH 5, while acid- tolerant varieties survive.
This is particularly the case for undigested pro- tein, which is linked to clostridium perfringens, the bacteria responsible for necrotic enteritis.
Gram positive bacteria – c perfringens, entero- coccus spp, streptococcus spp – are mainly sus- ceptible to MCFA, while gram-negative bacteria such as e coli, campylo- bacter jejuni and salmo- nella spp are more sensi- tive to SCFA.
For instance, the most studied formic acid or its salts increased acetic acid and decreased lactic acid concentrations in both ileum and colon contents.
Overall, organic acids have the potential to mod- ulate the microflora popu- lations and consequently microbial metabolites pro- duction along the GIT.
In addition, various or- ganic acids such as citric, formic, fumaric and lactic acid reduce environmental excretion of minerals namely calcium, phos- phorus, magnesium and zinc by improving their absorption and retention.
In the large intestine of pigs, SCFA are rapidly absorbed by the colonic epithelium to play a piv-
Photo: Dusan Petkovic
Jefo announces Lisa Nietschke as regional sales manager South Australia
Jefo Australia’s new regional sales manager South Australia Lisa Nietschke.
JEFO, a global leader in high-performance non-medicated nu- tritional solutions for animals, recently an- nounced that Lisa Ni- etschke joined the Jefo Australia team as re- gional sales manager South Australia, on February 8.
“Lisa not only has bachelor’s degree in animal science, and the practical experience of formulating and bal- ancing diets for mo- nogastric and ruminant animals, Lisa is also a member by examination of the Australian As- sociation of Ruminant Nutritionists.
Lisa has worked in Australian intensive industries for 12 years and has knowledge in all areas of monogastric and ruminant nutrition, as well as in research, development and exten- sion.
Jefo Australia’s man- aging director Wayne Bradshaw said, “Lisa will be an outstanding asset to the Jefo Aus- tralia team.”
President and founder of the Jefo Group Jean Fontaine said, “Lisa is a fantastic asset to the team led by Wayne Bradshaw, who has been working with our stra- tegic partners within Australia and New Zea- land for 16 years now, and our commitment is stronger than ever.”
Lisa has seen the real benefits that the Jefo matrix technology offers to modern day intensive animal production and performance.
“She has a wealth of knowledge and history in the Australian animal feed industry and I am honoured that she has joined our team.
“I am happy to join a company that is offering key solutions to provide a real return-on-invest- ment to the farmers,” Ms Nietschke said.
Lisa can be contacted on 0407 701 944 or at
Many acids are com- monly used as salts of sodium, potassium or cal- cium.
Australian Pork Newspaper, February 2021 – Page 15

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