Rethinking Protein in Pet Nutrition: From Traditional Sources to Alternative and Functional Proteins

In recent years, however, the discussion around protein has expanded significantly. Terms such as 'alternative proteins', 'novel proteins', and 'functional proteins' are increasingly used across the food and pet food industries. Much of this interest is driven by sustainability concerns and projections that global demand for protein will increase substantially as the human population approaches 10 billion by 2050 (FAO, 2022; OECD-FAO, 2023).
 

This raises an important question: do we truly need entirely new protein sources to feed our pets, or should we focus on improving how we utilize the protein sources we already have?
 

The answer likely lies somewhere in between. Traditional protein sources remain nutritionally robust, while emerging technologies and alternative ingredients offer opportunities to improve sustainability, functionality, and health outcomes—including effects on the gut microbiome.

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Global Protein Demand and the Sustainability Debate

Projections toward 2050 suggest that global protein demand will rise sharply as the world population approaches 10 billion, with food demand expected to increase by about 60% (FAO 2018; FAO 2022; Henchion et al., 2017). At the same time, the global pet population continues to expand, with an estimated 900 million dogs and cats worldwide. Approximately 60% of these animals are concentrated in Europe, the United States, China, and Brazil.
 

These trends have raised concerns about whether traditional livestock production alone can meet future protein needs. Critics often argue that feeding animal-derived proteins to pets competes with the human food supply and contributes to environmental pressures, such as land use, greenhouse gas emissions, and water consumption.
 

However, the picture is more nuanced. A significant portion of animal-derived ingredients used in pet foods originates from rendered co-products of the human food system, including organ meats, trimmings, and fish processing residues. These ingredients represent an efficient form of nutrient recycling within the food supply chain (Boland et al., 2013).
 

Advances in food processing technologies are also improving nutrient utilization, enabling greater recovery of proteins, peptides, and bioactive compounds from raw materials and by-products (Yuan et al., 2025). Improving how proteins are processed and utilized may therefore be as important as identifying entirely new protein sources.

Protein Requirements in Dogs and Cats

Protein requirements in companion animals are well established through decades of nutritional research. According to AAFCO guidelines (AAFCO 2026), the minimum protein requirement for adult dogs is approximately 18% on a dry matter basis, while growing puppies require 22.5%. Cats, as obligate carnivores, require higher protein intake, with minimum levels of 26% dry matter.
 

In commercial diets, however, protein levels are typically higher. Many dry dog foods contain 22–32% protein, while cat foods often range from 30–40% protein. These levels reflect both nutritional needs and consumer expectations, as protein content has increasingly become associated with perceived diet quality.

Traditional Protein Sources: Still the Foundation

Animal-derived proteins remain central to pet nutrition because of their balanced amino acid profiles and high digestibility. Common ingredients include chicken meals, beef and lamb meals, fish meals, fish protein concentrations, and meat or organ by-products. These ingredients supply essential amino acids, such as lysine, methionine, and taurine and typically exhibit digestibility values around 85–90%, although digestibility can vary depending on the specific ingredient and processing conditions.
 

Plant proteins also play a significant role in modern formulations. Ingredients such as soybean meals, pea protein, lentils, and chickpeas contribute valuable amino acids while offering flexibility and cost efficiency in formulation.
 

Recent innovations in food processing have further improved plant protein functionality. Technologies such as fermentation, enzymatic hydrolysis, and advanced milling can increase digestibility while reducing anti-nutritional factors such as lectins and protease inhibitors (Yuan et al., 2025).
 

These developments highlight an important point: innovation does not always require entirely new ingredients—sometimes it involves improving how existing ingredients are processed and utilized.

The Rise of Fresh and Minimally Processed Meat Ingredients

Over the past decade, the use of fresh meat or poultry has expanded significantly in dry pet food formulations. Many premium kibble products now incorporate fresh chicken, beef, or fish as part of their protein systems.
 

In many cases, these fresh ingredients originate from mechanically deboned meat (MDM) or automated meat recovery (AMR) processes, which efficiently recover edible muscle tissue from carcasses after primary cuts have been removed. These ingredients provide highly digestible protein while improving palatability and consumer perception.
 

Marketing narratives around 'fresh' ingredients have also been reinforced by the rapid growth of fresh and lightly cooked pet food formats. The fresh pet food market in the United States alone is estimated to exceed USD 3 billion and continues to grow (Packaged Facts, 2023). This trend illustrates how consumer expectations increasingly influence ingredient selection and processing strategies in the pet food industry.

The Rise of Alternative Proteins

While traditional proteins remain dominant, several emerging protein technologies are gaining attention.
 

Insect Proteins
Insects, such as black soldier fly larvae, mealworms, and crickets are being explored as sustainable protein sources. Insect meals typically contain 40–65% protein and can be produced using relatively small amounts of land and water compared with conventional livestock production (van Huis, 2021).
 

Insect proteins may contain bioactive compounds such as antimicrobial peptides and chitin that could influence immune function and gut health (Gasco et al., 2020). However, scaling production and achieving widespread consumer acceptance remain challenges.

Fermentation-Derived Proteins
Fermentation technologies represent another promising pathway. Microbial fermentation can produce single-cell proteins (SCP) using yeast, bacteria, fungi, or microalgae grown on various substrates (Matassa et al., 2016). These proteins can provide favorable amino acid profiles while requiring relatively small land footprints.
 

Traditional fermentation methods—such as koji fermentation using Aspergillus oryzae—can also transform plant substrates into more digestible and nutritionally enhanced ingredients (Yuan et al., 2025). Advances in biotechnology now allow engineered microbes to produce specific peptides or proteins with targeted functional properties.

Cell-Cultured Proteins
Cellular agriculture represents one of the most technologically ambitious approaches to protein production. By culturing animal cells in controlled environments, it may eventually be possible to produce meat without traditional livestock production (Post, 2012). Although promising, this technology is still in its early stages—particularly for pet food applications—and faces challenges related to cost, energy use, and regulatory frameworks.

Protein and the Gut Microbiome

One of the most exciting areas linking protein nutrition and health is the gut microbiome.
 

The gut microbiota plays a central role in digestion, immune function, and metabolic health in companion animals. Diet composition—including protein source and digestibility—can significantly influence microbial communities in the gastrointestinal tract (Handl et al., 2013).
 

Highly digestible proteins reduce the amount of undigested nitrogen reaching the colon, minimizing the production of undesirable fermentation by-products, such as ammonia or biogenic amines.
 

Conversely, certain peptides and amino acids may serve as substrates for beneficial microbial populations, contributing to the production of short-chain fatty acids and other metabolites that support intestinal health (Sandri et al., 2017).

Key Takeaways

The conversation around alternative proteins often frames the issue as a replacement of traditional proteins. Actually, the future of protein in pet nutrition will likely be more integrated and from this discussion, several key insights emerge:
 

1. Traditional protein sources remain nutritionally efficient. Animal and plant proteins continue to provide reliable amino acid nutrition and will remain foundational ingredients in pet food.
    
2. Alternative proteins expand the toolbox; insects, microbial fermentation, and cellular agriculture may complement existing protein systems.
    
3. Processing technology and advances in fermentation, enzymatic modification, and ingredient recovery can improve nutrient utilization, reduce anti-nutritional factors, and enhance the functional value of protein ingredients.
    
4. Consumer expectations are reshaping protein systems. The growth of fresh, minimally processed, and high-protein pet foods illustrates how market trends increasingly influence ingredient selection and processing technologies.
    

Ultimately, the goal should not be to replace traditional proteins with alternatives but to develop a diverse and efficient protein ecosystem that supports sustainability, nutrition, and pet health. The key question is not only which proteins we choose, but how intelligently we use them.

By Juan Gómez-Basauri, Ph.D. - MAGELLAN LLC
Source: All Pet Food Magazine

References
AAFCO 2026. Association of America Feed Control Officials. Official Publication

Boland, M., Rae, A., Vereijken, J., Meuwissen, M. P. M., Fischer, A. R. H., van Boekel, M. A. J. S., Rutherfurd, S. M., Gruppen, H., Moughan, P. J., & Hendriks, W. H. (2013). The future supply of animal-derived protein for human consumption. Trends in Food Science and Technology, 29(1), 62-73.https://doi.org/10.1016/j.tifs.2012.07.002

FAO. 2018. The future of food and agriculture – Alternative pathways to 2050. Summary version. Rome. 60 pp. Licence: CC BY-NC-SA 3.0 IGO.https://openknowledge.fao.org/handle/20.500.14283/i8429en

FAO. 2022. The future of food and agriculture – Drivers and triggers for transformation. The Future of Food and Agriculture, no. 3. Rome.https://doi.org/10.4060/cc0959en

Gasco, L., Gabriele Acuti, Paolo Bani, Antonella Dalle Zotte, Pier Paolo Danieli, Anna De Angelis, Riccardo Fortina, Rosaria Marino, Giuliana Parisi, Giovanni Piccolo, Luciano Pinotti, Aldo Prandini, Achille Schiavone, Genciana Terova, Francesca Tulli & Alessandra Roncarati (2020) Insect and fish by-products as sustainable alternatives to conventional animal proteins in animal nutrition, Italian Journal of Animal Science, 19:1, 360-372.https://www.tandfonline.com/doi/pdf/10.1080/1828051x.2020.1743209

Handl S., German AJ, Holden SL, Dowd SE, Steiner JM, Heilmann RM, Grant RW, Swanson KS, Suchodolski JS. Faecal microbiota in lean and obese dogs. FEMS Microbiol Ecol. 2013 May;84(2):332-43. Epub 2013 Jan 24. PMID: 23301868.https://doi.org/10.1111/1574-6941.12067

Henchion, M. Hayes M, Mullen AM, Fenelon M, Tiwari B. Future Protein Supply and Demand: Strategies and Factors Influencing a Sustainable Equilibrium. Foods. 2017 Jul 20;6(7):53.https://pmc.ncbi.nlm.nih.gov/articles/PMC5532560/

Matassa, S., Boon N, Pikaar I, Verstraete W. Microbial protein: future sustainable food supply route with low environmental footprint. Microb Biotechnol. 2016 Sep;9(5):568-75. Epub 2016 Jul 8.https://pmc.ncbi.nlm.nih.gov/articles/PMC4993174/pdf/MBT2-9-568.pdf

OECD/FAO 2023. OECD-FAO Agricultural Outlook 2023-2032, OECD Publishing, Paris.https://doi.org/10.1787/08801ab7-en.

Post MJ. Cultured meat from stem cells: challenges and prospects. Meat Sci. 2012 Nov;92(3):297-301. doi: 10.1016/j.meatsci.2012.04.008. Epub 2012 Apr 11. PMID: 22543115.https://doi.org/10.1016/j.meatsci.2012.04.008

Sandri, M., Dal Monego S, Conte G, Sgorlon S, Stefanon B. Raw meat-based diet influences fecal microbiome and end products of fermentation in healthy dogs. BMC Vet Res. BMC Vet Res 2017; 13 (1):65.https://pmc.ncbi.nlm.nih.gov/articles/PMC5331737/

van Huis, A. Prospects of insects as food and feed. Org. Agr. 11, 301–308 (2021).https://doi.org/10.1007/s13165-020-00290-7

Yuan, Yi, Xinyao Wei, Yuhong Mao, Yuxue Zheng, Ni He, Yuan Guo, Ming Wu, Joseph Dumpler, Bing Li, Xu Chen, Xixi Cai, Jianping Wu, Yongqi Tian, Sihan Xie, Jeyamkondan Subbiah, Shaoyun Wang. Innovative Food Processing Technologies Promoting Efficient Utilization of Nutrients in Staple Food Crops, Engineering, Volume 50, 2025, Pages 229-244.https://doi.org/10.1016/j.eng.2025.04.014