Glossary of common terms used in pig nutrition

Sudden and severe onset of symptoms (e.g. from mycotoxin consumption), usually associated with great exposure over a short period of time.

The main energy source in pig diets; examples are sugar, starch and fibre. The main source of carbohydrates for pigs is cereal grains, such as wheat, oats and barley.

Long-term health effects usually a result of prolonged exposure to low levels of, for example, mycotoxins.

A trace mineral, required by pigs, which has several biological functions. Studies have previously demonstrated a performance benefit to copper levels exceeding pigs’ nutritional requirements and this led to the use of higher levels of copper to promote growth. However, adding higher levels of copper to the diet subsequently increases the amount of copper being excreted by the pig in faeces and, when this is applied as manure to land, it can lead to accumulation in the soil, which has negative repercussions for the environment.

For this reason, maximum copper inclusion levels allowed in pig feed are legislated by the EU.

An essential macronutrient and a rich source of energy. The main sources of fat used in pig diets are plants (such as soya oil) or animals (such as fish oil).

A mixture of feed materials (often grain-based) that have been ground to form smaller particles.

A reduction in growth rate in the immediate post-weaning period.

Caused when the pig’s body temperature increases above a certain limit. Pigs will increase their respiration rate to attempt to keep cool, then search for environmental opportunities for cooling.

When an individual’s immune system has a reduced or supressed response to infection.

Naturally synthesised by animals but is also available synthetically and can be supplemented in pig feed. It is an amino acid precursor involved in the transport of long chain fatty acids into cells for energy production.

The minimum temperature that can be tolerated by pigs. Once pigs reach this temperature or below, they attempt to increase their body temperature using mechanisms such as shivering or by increasing their feed intake.

An essential amino acid that cannot be synthesised by the pig but must be supplied in feed. It is required to build muscle protein. It is often the first ‘limiting’ amino acid, meaning that it is often the first amino acid to become deficient in pigs. Without it, protein cannot be formed.

Essential nutrients to ensure normal pig bodily processes. Important minerals for consideration in pig diets include calcium, phosphorus, sodium, zinc, copper and iron.

An energy value that considers the energy is available to the pig for growth and maintenance after accounting for the energy lost in faeces, urine and heat production.

An upset of the balance between reactive oxygen species and antioxidants in the animal (either an excess of reactive oxygen species or a reduction in antioxidants). The result is inflammation, which can cause several symptoms in pigs, such as decreased feed intake, reduced immunity, damage to the liver and muscle degeneration.

An enzyme that can be added to feed to aid the breakdown of phytate (the principal storage form of phosphorus in plants), which results in more phosphorus being available to the pig.

Non-digestible food substances that selectively stimulate the growth of favourable species of bacteria in the gut. Because they are not digested and absorbed by the pig, prebiotics provide a readily available substrate for ‘good’ bacteria to grow. They includes some fibre sources, such as wheat bran.

Live cultures of microorganisms that can be supplemented in pig diets. They work by improving the microbial balance of the gut. Probiotics include yeasts (for example Saccharomyces spp) and bacteria (for example lactobacillus spp).

An essential nutrient for growth and maintenance of the pig. While pigs do not have a requirement for crude protein, they do have a requirement for amino acids, which are the structural units of protein. Pigs require a careful balance of amino acids to ensure optimal health and performance. Crude protein is the nitrogen content of the feed multiplied by a factor (6.25). In recent years the crude protein content of feed has been reduced by the use of crystalline amino acids; effectively the protein quality has been increased. This reduces N excretion, ammonia, water intake and the risk of gut disturbances.

Amino acids in feed ingredients are not fully available to the pig. Measuring standardised ileal digestible (SID) amino acids therefore considers the digestibility of amino acids available at the end of the small intestine (ileum). SID is the most accurate measure of amino acid availability to the pig.

When two or more mycotoxins combine to produce a potentially greater effect on the pig.

The range of ambient temperatures over which pigs can maintain their normal body temperature without affecting their heat production. It is the range between the lower critical temperature and the upper critical temperature.  

Essential micronutrients for normal pig bodily functions. Pigs require several vitamins, including vitamins A, D, E and K (fat-soluble vitamins) and niacin, riboflavin and biotin (water-soluble).

An essential nutrient for pigs. Water is needed for metabolic and physiological processes in the body and, if not available, these processes cannot occur. It is important to ensure that all pigs, regardless of stage of production, have ad lib access to water.

An enzyme that can be added to pig feed to aid the breakdown of hemicellulose, a major component of plant cell walls. This releases nutrients that would otherwise have been unavailable to the pig.