Acids in Pig Feeds  

Introduction:

The ban of Antibiotic Growth Promoters means that new growth promoting alternatives need to be investigated. Acids in particular are a key area of interest as research has indicated that there are many benefits to adding acids to pig feeds. Acids improve performance but also act in similar ways to antibiotic growth promoters by enhancing the health of the pig.

There are many types of acids used in the feed industry; these include formic, lactic, acetic, propionic and citric acid. Inclusion is normally a mixture of two or three acids.

Due to their small structure, acids are absorbed very easily and quickly in the digestive tract. Protecting the acids by encapsulating them in a substance, allows for them to be released slowly. Protecting acids allows for targeted action at specific points along the digestive tract.

Acids have been used as preservatives for many years and only recently have the direct effects on the animal been researched. The benefits of including acids in the feed are outlined below.

The benefits of acids:

• Lowers pH

The digestive tract has a varying pH along its length from pH 2 to pH 7.5. The majority of bacteria that cause disease cannot live in conditions where the pH is lower than 4 or 5.

• Inhibits growth of undersirable bacteria

Bacteria such as E. Coli, Salmonella and Clostridium can cause illness in pigs. These bacteria require optimum conditions to multiply and a low pH environment is not favourable. The acids penetrates the wall of the bacteria and a reaction inside the cell disrupts DNA synthesis. Without DNA synthesis, the bacteria cannot multiply; therefore the number of harmful bacteria is reduced.

• Improves health status

As mentioned above, the decrease in pH creates an environment where harmful bacteria cannot grow. These harmful bacteria can cause diarrhoea or mastitis. Reducing the number of bacteria reduces the risk of disease.

• Increases growth of beneficial bacteria

Lowering the pH makes the environment of the digestive tract more suited to bacteria such as Lactobacilli, bifldobacteria and propioibacteria, which aid digestion. Increasing digestion, allows for more nutrients to be absorbed.

• Increases digestibility

The lower pH increases the activity of enzymes in the digestive tract, causing feed, especially proteins, to be broken down more rapidly. Due to the low pH the total number of bacteria in the gut is lowered, so there is less competition for nutrients and the pig can absorb more.

• Increases feed intake

If feed is more digestible then there is less feed in the digestive tract, meaning that the animal does not feel full and will increase feed intake.

• Improves animal performance

An increase in feed intake, nutrient absorption and better health, will all result in better performance. The pig is receiving more nutrients and is not wasting energy on combating disease. All the extra nutrients and energy can be used for growth. A faster growth rate will mean fewer days to slaughter and therefore will reduce production costs.

The inclusion of acids in the feed can be beneficial to all stages of production:

• Growers:

At weaning, the piglet’s digestive tract is not yet mature. The change of diet and the stress can lead to post-weaning diarrhoea. This can cause dehydration, reduced performance and even death.

As the digestive tract is not mature, it does not secrete enough acid. Acid is required to activate an enzyme to breakdown proteins. If this does not occur then the protein cannot be absorbed and the piglet does not receive enough nutrients. Also the large proteins are favourable resources for the undesirable bacteria to feed on. Lowering the pH by including acids in the feed, overcomes this problem.

The post-weaning piglets immune system is also not mature, making them more susceptible to disease. Creating a lower pH in the digestive tract inhibits the growth of bacteria, such as E. coli, that cause disease. The addition of acids therefore boosts the piglets defence system against disease.

Finishers:

Acids can also be beneficial to finishers as trials have shown that acids lower the risk of scour. Acids also improve growth rate, a faster growth rate means fewer days to slaughter. This reduces feed usage and lowers costs.

Carcass quality may also be improved when acids are added to the feed.

Sows and gilts:

Inclusion of acids in the feed through gestation and lactation can reduce the occurance of MMA syndrome (mastitis, mertritis and agalactia).

Acids reduce the number of pathogens in the faeces, minimising the risk of contact between harmful bacteria and the piglets.

A lower pH in the digestive tract improves the digestion of calcium. Calcium is an important component of milk, is important for piglet bone growth and can also help prevent still births.

Sows and gilts fed on acids through gestation and lactation were found to have larger litters, with more born alive. Piglet birth weight and weaning weight were also increased.

The risk of Salmonella:

Salmonella is a bacterium that causes food poisoning in humans. For this reason, abattoirs test animals for salmonella levels and animals from farms that continuously contain high levels of salmonella can be penalised.

The digestive tract of the pig offers a very suitable environment for salmonella to grow. The pigs can show no symptoms and just be a carrier of the bacteria, which they pass on to other pigs. Others will get diarrhoea and as a result performance is reduced.

Testing for the quantity of salmonella antibodies present can monitor salmonella levels. An animal that has had more contact with salmonella will have a higher quantity of salmonella antibodies. Testing is done at the abattoir and recorded for each farmer. Depending on the quantity of animals that test positive, each farmer is assigned a ZAP category. The categories are scheduled to change from June 2006, to help crack down on salmonella levels. The new limits for each category are listed in the table below:

Farmers that are in ZAP category 2 and 3 must take action to reduce the number of animals testing positive within 6 months of being tested. Farmers in ZAP category 1 must ensure that salmonella levels do not rise. Farmers that are continuously in category 3 may be unable to sell their pigs under the QSM Mark and may even incur a penalty.

Adding acid to the feed will reduce the number of animals testing positive for salmonella and will help to maintain low levels of salmonella on farm. This is because salmonella cannot survive in an environment where the pH is low. Adding acid to the feed lowers the pH of the digestive tract.

Acid in the feed also acts as a preservative, reducing the chance of salmonella being ingested from infected feed.

Below is an action plan designed to minimise the levels of salmonella on farm by using acids in feed.

Feeding programme:

Zap category 1:

1. To maintain low salmonella levels we recommend the use of an acid e.g. Formic/Lactic acid blend, included at 2kg/tonne.
2. 2kg will cost approximately £2.20/tonne of finished feed.

Zap category 2 and 3:

1. Feed 5kg/tonne of Formyl for 2 to 4 weeks prior to slaughter to reduce the number of salmonella.
2. 5kg Formyl costs £13.75/tonne of finished feed.
3. To maintian low levels, follow advice for Zap category 1.

Summary:

• Acids can be used as an alternative to antibiotic growth promoters

1. -        Lowers pH in the digestive tract
2. -        Decreases levels of undesirable bacteria

• Increases performance

1. -        Increases feed intake
2. -        Improves digestibility
3. -        Increases daily liveweight gain

• Improves health

1. -        Reduces risk of post-weaning diarrhoea
2. -        Reduces the risk of MMA syndrome
3. -        Reduces level of salmonella

Here at A-One Feeds we use the best quality products that have been extensively researched and proven to give excellent results.

For more information about the use of acids in your pig feed please contact your A-One representative or the Dishforth offices on 01423 322706.