09/07/2021 3 min

Animal protein in pig and poultry feed: separate production to limit risks

Cases of bovine spongiform encephalopathy (BSE), also known as mad cow disease, have become extremely rare in Europe. The European Commission thus envisions allowing Member States to relax the regulation that prohibits the use of animal protein in the feed of farmed animals under certain conditions. ANSES received a formal request to assess the risks to animal and human health of reintroducing animal protein in this way.

The European Commission is currently reviewing whether to allow the use of processed animal protein (PAP) from poultry in pig feed and PAP from pigs in poultry feed. Processed animal protein is exclusively made from by-products of animals slaughtered for human consumption (see box below). The European Commission also envisions allowing insect PAP for pigs and poultry.

Avoiding prion diseases

The main risk associated with incorporating poultry and pig protein into animal feed is the transmission and amplification of transmissible spongiform encephalopathies (TSEs). These diseases are transmitted by prions – infectious protein particles – which can spread if products from an infected animal end up in the feed of animals of the same species. This is called disease amplification. 

The current European regulation lays down certain rules to avoid this risk. The first is the “non-cannibalism” principle, which states that feeding an animal processed animal protein from its own species is banned. Furthermore, since ruminants are known to be potential carriers of TSEs such as BSE in cattle or scrapie in sheep and goats, PAP derived from ruminants is banned from the feed of all farmed animals. 

Lastly, if poultry PAP is authorised in pig feed and vice-versa, the draft European legislation will provide for effective separation by species on production sites, from the slaughterhouse to feed delivery at the farm. However, the regulation under review includes a provision for waivers to be granted under the responsibility of Member States. In practice, in France as in other European countries, some slaughterhouses and feed production plants handle several species. 

The need for strict separation in the feed production chain

The approach of ANSES experts was to identify risk situations in which TSEs, whether known or unknown in the industry, could be transmitted and amplified, and could get out of control a decade later, as in the case of the BSE agent in the 1980s,” says Charlotte Dunoyer, head of the unit for the assessment of risks related to animal health, nutrition and welfare at ANSES. “The BSE epidemic most likely developed from a very small number of cases, or even a single case, which was then amplified through intra-species recycling of cattle by-products.”

The main risk of TSE transmission would be through cross-contamination, which is when animal by-products not intended for a species end up in food for that species. Such contamination can occur before PAP manufacture (at the slaughterhouse and during by-product collection), during PAP manufacture, or afterwards in the feed production plants that use PAP, as well as during different stages of transport.

Mixed slaughterhouses that handle several species are the weakest link in the production chain and have been shown to present the highest risk of transmission. Pigs have been shown in experiments to develop the disease if contaminated by some ruminant TSEs, when for instance, parts of ruminant carcasses are accidentally mixed with poultry carcasses during the manufacture of poultry PAP for pig feed. The risk is at its lowest when there is effective separation by species of all the sites in the production chain. ANSES therefore recommends strict compliance with this rule. 

Insects considered for feed

While insects currently pose little risk of TSE transmission, they could transfer pathogenic micro-organisms and chemical contaminants to pigs and poultry. To avoid this, ANSES recommends complying with a number of health rules as regards the rearing of insects intended for use in the feed of farmed animals. The insects’ food source should comply with applicable regulations on the feed of farmed animals. This means that insects should not be fed waste or faeces, which are major sources of microbial contamination. Similarly, they must be completely cleared of the substrate on which they were reared before processing into PAP can begin. A 24-hour fasting period would eliminate any contaminants that might be present in the insects’ gut. Lastly, some species can retain heavy metals such as lead, cadmium or arsenic. Insect PAP should therefore be monitored to detect these contaminants.


What is processed animal protein?

Processed animal protein is made from by-products of animals slaughtered for human consumption. It derives from parts of healthy animals that are not marketed in France because of French eating habits and because of their lower nutritional value. 

Ruminant tissue such as from the central nervous system presents the highest risk of containing prions and thus of transmitting TSEs, and is not included in PAP. Fallen or euthanised animals cannot be used in PAP production, nor can carcasses of sick animals. Processed animal protein is therefore different to the meat-and-bone meal used for animal feed in the past.

Processed animal protein is of nutritional interest, especially for young animals as it is rich in easily digestible protein and energy. It also reduces dependence on imported sources of protein, such as soybean. 

Which regulations ?

In 2001, after various policies limited its use in France in the 1990s, meat-and-bone meal was completely banned from farmed animal feed in Europe due to the TSE risk. Since 2013, pig, poultry and insect PAP has been progressively allowed in aquaculture. Processed animal protein is also used as feed for pets and for animals raised for their fur.