BuRO opinion on risks of bromoform by adding seaweed of the genus Asparagopsis to feed for ruminants

Other opinions

Seaweed of the genus Asparagopsis contains high concentrations of bromoform. That is a substance that can prevent the formation of methane in the rumen of the cow. There is no obligation in the current legislation to assess the safety for humans and animals when adding Asparagopsis to feed. BuRO recommends revising the current legislation on animal feed. Make a safety assessment legally mandatory if raw materials containing active substances such as Asparagopsis are added to feed.

BuRO also recommends that more research should be carried out into the risks to animal health and welfare if ruminants receive feed containing Asparagopsis. Particular attention needs to be paid to the already observed health effects and the (possible) effects that are not yet visible.

Furthermore, BuRO advises the Inspector General of the NVWA to follow the developments of feed aimed at methane reduction and to draw attention to animal health, animal welfare and food safety.

Background

In order to achieve the global climate goals, greenhouse gas emissions must be reduced. About 15% of emissions comes from the agricultural sector. Cattle contributes the most to methane emissions. Ways are therefore being sought to reduce methane emissions from ruminants.

One way to reduce methane emissions is to add the seaweed Asparagopsis to feed. Research has shown that adding this seaweed to feed can reduce methane emissions, due to the substance bromoform in the algae. There is still little research available on the potential risks of bromoform for animal health and its transfer to animal products, such as milk and meat.

Research by Wageningen University & Research (WUR) has shown that feed containing Asparagopsis may pose a risk to animal health. Bromoform may also end up in milk and urine. Consumers can then ingest bromoform if they consume the milk.

Feed may only be placed on the market and used if it is safe. Feed shall also not have a direct adverse effect on the environment or animal welfare. Seaweed is on the list of authorised feeding materials and may be added to feed. There are no legal limits for the presence of bromoform in feed or products of animal origin. Following WUR's investigation, the Ministry of LVVN asked BuRO to carry out a risk assessment.

Answer to the questions

BuRO wanted to answer several questions with this risk assessment.

Questions 1 and 2: Is there a risk to the health of consumers if they consume products of animal origin with bromoform? What is the maximum level of bromoform that may be present in products of animal origin before a risk to the health of the consumer occurs?

Bromoform is measurably transferred to cow's milk. Cow's milk should not contain more than 232 μg bromoform/L. At a higher level, the health-based guidance value is exceeded if toddlers consume large amounts of cow's milk over a longer period of time. The maximum level protects toddlers and the rest of the population and is a factor of 7 to 76 above the highest reported level in cow's milk in the literature (35 μg/L). Adding Asparagopsis to cow feed is unlikely to lead to bromoform levels in cow's milk that pose a risk to consumer health.

Question 3: What is the maximum daily dose of bromoform that may be present in feed before the maximum safe content in products of animal origin is exceeded?

It is not possible to establish a maximum bromoform content in feed that does not result in the maximum safe bromoform content in products of animal origin being exceeded in daily feeding of Asparagopsis.

One appropriate study showed that an average daily bromoform intake of 132 mg, 266 mg, 398 mg and 432 mg resulted in an average bromoform residue level in milk of 2 μg/L, 4.3 μg/L, 7.1 μg/L and 5.2 μg/L respectively. In addition, there are indications that the exposure method (including pulse feeding or prolonged exposure, or, for example, administration as dried algae or oil extract) may have an effect on the absorption into the body of the animal and therefore the degree of transmission.

Question 4: Is there a risk to the health and welfare of the animal if bromoform is taken via feed?

If sheep and cattle are exposed to bromoform from Asparagopsis via feed, this can have an effect on the rumen mucosa within a few weeks. For example, the mucosa can become irritated or inflamed. This depends on the concentration of Asparagopsis in animal feed. The literature consulted does not provide enough information to make statements about the exact concentrations at which these effects occur. There is a risk to the health and welfare of the animal if bromoform is taken via feed.

Question 5: What is the maximum level of bromoform that may be present in feed before a risk to the welfare and health of the animal occurs?

No data are available to confirm the degree of health damage or discomfort to the animal, in particular in case of very long (year-long) pulsed or continuous exposure of bromoform in feed. Therefore, currently no maximum level of bromoform in feed can be indicated. It is unknown which exceedance poses a risk to the health and welfare of the animal.