In years past, we seldom pondered phosphorus availability in pet diets. That was because phosphorus was often found in excess (see Petfood Industry magazine, July 2021). With animal-based protein concentrate meals (rendered proteins), the level of phosphorus has been abundant and the bioavailability high — nearing 100%.
However, as we consider some of the new diets coming into the market which tout their intentional use of plant-based proteins for dietary claims such as vegetarian, flexitarian, limited animal proteins, sustainable and vegan, the nutritional considerations start to get more complicated. This is because these new diets, with their heavier reliance on plant-based proteins, bring along some differences in structural (fiber) and nonstructural (oligosaccharide) carbohydrates. They also possess differences in the essential fatty acids and vitamins. However, the most important difference is in the minerals, especially phosphorus. This is due to a phosphorus storage system that is unique to plants. Going forward, we need to get a better handle on how to manage plant-based phosphorus in pet foods.
