The digestibility of nutrients and energy in four novel protein pet food ingredients recently was studied in comparison with four traditional proteins by a team of animal nutritionists and veterinarians. Some of those protein sources turned out to have clear dietary advantages over others.

“Our results demonstrate that a wide variability in quality and digestibility exists among animal-based protein sources,” study co-author and University of Illinois at Urbana-Champaign professor, Kelly Swanson, PhD, told Petfood Industry. The Journal of Animal Science published his team's results.

What pets actually get from novel protein food ingredients

The quantity of a particular nutrient in an ingredient may not reflect what an animal actually gets from the food during digestion. Swanson’s team examined the actual nutrient digestibility and metabolizable energy in pork peptone, calamari, alligator, lamb, venison, chicken and two forms of duck meal. 

“Based on amino acid profile, calamari meal and chicken meal seemed to come out the best,” said Swanson. “Based on nutrient digestibility, calamari meal and pork peptone performed the best.

“Lamb meal was consistently the lowest in terms of digestibility, with venison being second lowest for most nutrients,” he said.

The low scores for lamb and venison may mean that a closer look at these protein sources may be worthwhile to see if they consistently underperform, Swanson said. Raw material quality and processing can greatly affect the results for a particular protein source though, he noted. So, the results of the study might not hold for all sources of the same types of protein, since the scientists only used one source of each variety, with the exception of two sources for duck.

Testing new cat and dog food ingredients

Pet food companies may want to consider the value of conducting digestibility research on novel protein pet food ingredients, suggested Swanson.

“Most companies probably focus on nutrient analysis and avoid digestibility testing due to the expense and time of animal studies,” Swanson said. “Our data suggests, however, that this testing is important in determining the quality of proteins and should be done when considering new ingredients.”