EFSA Scientific Opinion on the Maximum Total Dietary Level of Vitamin D3 for Salmonids and its Potential Impact on Pet Food Formulations and Supplementation.

Following the recent EFSA Scientific Opinion on increasing the maximum permitted feeding level of Vitamin D3 for salmonids (for example salmon and trout) from 3,000 IU/kg to 60,000 IU/kg, it is important for the pet food industry to consider the impact of this potential future change on vitamin D3 levels in salmon and trout by-products, and ultimately vitamin D3 levels in finished pet foods.  It would be prudent at the same time to also evaluate all total trace element levels in pet foods.

Vitamin D3 in pet foods

The FEDIAF published allowances for vitamin D3 in dog and cat diets are detailed below.

 

 

 

 

In the FEDIAF Code for Labelling of Pet Foods it states that vitamins can be included with a ‘’value higher than the legal maximum laid down in the legislation, when processing losses require higher levels to be added in order that nutritional standards are maintained in the finished product.’’  However, the total in the finished feed after processing should be less than the MPL which, for cats and dogs, is currently 2000 IU/kg pet food (at an 88% DM content), which is 2272 IU/kg on a DM basis. 

Vitamin D is an important part of the diet, being essential for calcium and phosphorus regulation in the blood, bone mineralisation and skeletal growth, and playing an important role in the immune system.  Therefore, we need to ensure that complete pet foods are formulated to meet animal requirements throughout the shelf life of the finished product, allowing for losses during processing and storage.          

Traditionally, pet foods have been supplemented with levels of vitamin and trace elements close to published nutrient allowances in order to meet the animals’ requirements, not considering greatly background levels within the diet.  However, over the past 10 years, pet food formulations have changed dramatically from being cereal based diets with meat meal inclusions, to being low cereal or cereal free with increasingly high inclusions of meat and fish products.  This has inevitably had an impact on the background profile of nutrients within pet food formulations.

Diets more likely to be at risk of exceeding the MPL for vitamin D3 are those high in salmon or fish by-products, or salmon or fish oils.  High meat or meat by-product contents also increase the risk of exceeding the MPL.  Of course, total background levels of vitamin D3 will vary depending on the type and quality of the raw material (fresh, meat/fish meals, the part of the fish/animal being used), and the quantity in the overall formulation.  There could also be some seasonality changes within raw materials, and the processes and temperatures used for manufacture will have an impact on losses of vitamin D3.

For this reason, it is very important to analyse key raw materials and finished pet foods on an ongoing basis to establish finished pet food vitamin D3 levels (and other vitamin and trace element levels that will be covered in more detail later).  As with all analysis of raw materials or pet food, it is important not to rely on just a single data point, but to build an ongoing picture of nutrient levels in the pet foods that takes into account any seasonality and any batch to batch variation.  It is worth pointing out that how analysis results are expressed and the units used can vary, so it is important to check these and convert where necessary. 

It is also important to note that the analytical error of vitamin D3 can be high, so it is recommended to seek clarification of the standard error from the laboratory used.  Nevertheless, building a database and showing due diligence in determining dietary levels of certain nutrients in your range of pet food should be an important part of the quality schedule. 

Recent Vitamin D3 Alerts in Pet Food

Although not yet passed into legislation, EFSA’s recently published scientific opinion could result in significantly increased background vitamin D3 levels in salmon and its by-products.  Already we are seeing high levels of vitamin D3 in some pet foods, and the impact of this potential change in the vitamin D3 supplementation of salmonids needs careful consideration by pet food formulators, manufacturers and brands

Vitamin D3 levels exceeding maximum permitted feeding levels have been brought to the forefront by pet food recalls over the last 12 months.  One of the recalls has been caused by issues with the vitamin D3 supplementation, however, the cause of the other recall is unknown but high background vitamin D3 levels in certain types of pet food cannot be discounted as a potential cause.

High levels of vitamin D that are fed for a short period of time should not cause health problems, however, feeding for a longer period of time can cause potential health issues such as loss of appetite, vomiting, excessive thirst, diarrhoea, increased urination and ultimately kidney damage.

Reviewing Pet Food Supplementation to Ensure Suitability

Premier Nutrition has been working proactively with customers for some time, where new ranges have been developed, or existing ranges have been reviewed, to assess and evaluate background levels of nutrients for which there is an MPL.  Where it is apparent that nutrients may exceed the MPL, premixes are reviewed and a suitable approach taken to ensure diets are satisfactorily balanced to meet animal allowances, but without exceeding MPLs as a result of supplementation.

It is important to evaluate the entire range for which a premix is used, and to consider all nutrients for which there is an MPL.  The key nutrients for which we have previously highlighted there may be issues in high fish and meat diets are:

  • Vitamin D3
  • Iodine
  • Selenium
  • Zinc
  • Copper. 

As mentioned before, background levels can vary greatly depending on the raw materials being used, and their inclusions.  So, it is important that time is taken to understand the materials, formulations and processes used for a pet food range.

If, following review, the vitamin D3 (or any other nutrients) are at risk of exceeding the MPL, there are several approaches that can be taken:

  • Lower the supplemental vitamin D3, or trace element concerned, or total removal of vitamin D3 or trace element, from the premix
  • This may mean having 2 premixes for a range of pet foods, where some formulations require higher levels of vitamin D3 (or other trace element) supplementation, but others require lower, or perhaps no supplementation.
  • Another solution maybe to have the base premix without vitamin D3 and the trace elements at risk of exceeding MPLs, and then a ‘top up’ premix that can be used at variable levels to increase those nutrients in the formulations that require it.

When reviewing supplementation, it is important to consider the FEDIAF allowance for the animal and ensure that sufficient nutrients will be present in the pet food following extrusion, and in the case of vitamins, until the end of the product shelf life.  However, when adding supplemental vitamins and trace elements, the MPLs should not be exceeded.

There may be some cases where the MPL is exceeded, even without supplementation.  In these cases, it may be prudent to clarify with FEDIAF that the same interpretation will be made as that for selenium, i.e. if everything possible has been done to reduce the level (i.e. no supplementation) but by the nature of the product (e.g. high in salmon) it is above the MPL, then it may be permitted.  However, in the case of vitamin D3, this approach may, or may not, be accepted going forward, if vitamin D3 levels become significantly higher if and when vitamin D3 feeding levels to salmonids are increased by such a large proportion.  This will need future clarification from FEDIAF.

If you would like any further information about vitamin D3 in pet food diets, or require a review of your pet food supplementation strategy, please do not hesitate to contact one of the Premier Nutrition Pet team.