How Effective Are Hydrolyzed Diets?

Hello, Summarians!

Diet and nutrition play a major role in animal health. That is why it can be so frustrating that we rarely get independent information. Hence, here is the nutrition edition.

I would love to hear your thoughts on these topics…

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Best Oils For Homemade Diets

Home-prepared pet diets depend on accurate nutritional databases and reliable ingredient labeling. Yet, plant oils—the primary source of essential fatty acids like linoleic and alpha-linolenic acids—often fail to match either their label claims or USDA database values. Breeding and processing trends have produced many seed and nut oils with reduced PUFA content for heat stability, so formulators relying on standard database entries may unknowingly under- or over-supply critical nutrients. Moreover, PUFA are highly prone to oxidation, leading to nutrient loss, off-flavors, and potentially harmful byproducts; this study used free fatty acidity, peroxide valu,e and induction time assays to track oil stability over 12 months. 

Analysis of twelve commercial oils showed that corn and walnut oils consistently exceeded their expected linoleic acid levels, while safflower and sunflower oils proved highly variable, some falling well below USDA values and others far above. Label claims and marketing terms such as “refined,” “pure,” or “cold pressed” were frequently misleading or contradictory, even though most oils remained relatively stable under controlled, refrigerated storage. Given that minor deviations in oil composition can disrupt the fatty-acid balance of home-prepared recipes—and that typical household storage conditions may accelerate oxidation—the authors recommend choosing oils proven to match database profiles, using them before their expiration dates, minimizing exposure to air and light (ideally by refrigeration), and enlisting qualified formulators to ensure dietary adequacy. 

Larsen, J.A., Stockman, J., Li, X. and Wang, S.C. (2025), Fatty Acid Analysis and Stability of Selected Edible Oils Used in Homemade Pet Diets. J Vet Intern Med, 39: e70119. https://doi.org/10.1111/jvim.70119 

Bottom line — Good information.

Effectiveness of Hydrolyzed Protein Diets

Chronic enteropathy (CE) in dogs encompasses a range of conditions marked by persistent or recurrent gastrointestinal signs and is classified based on therapeutic response into food-responsive enteropathy (FRE), microbiome-modulation responsive enteropathy (MrMRE), immunomodulator-responsive enteropathy (IRE), and non-responsive enteropathy (NRE). When serum albumin or total protein levels are low, CE is further categorized as protein-losing enteropathy (PLE). In clinical practice, dietary trials—often using fiber-enriched, hydrolyzed, or novel protein diets—are recommended as the first therapeutic step. Despite this recommendation, more than half of the dogs referred to specialist care in the study had never trialed a hydrolyzed diet, and up to 13% were already on antibiotics or immunomodulators at referral. This indicates inconsistency in first-opinion management and highlights the risk of misclassifying dogs with potential FRE as NRE if diet trials are not performed or are inadequate. 

In dogs without prior dietary intervention (naïve-CE), all cases began a soy-based hydrolyzed diet at their initial specialist consultation. Most maintained normal serum protein and albumin levels, and about 20% received diet alone without additional medications; in this subgroup, the majority achieved normal stool consistency within four weeks. In cases requiring concurrent therapies, probiotics were the most commonly added treatment, despite limited evidence for their benefit over diet alone. Antibiotics and immunomodulators were introduced in some dogs based on clinician judgment, but diet remained the foundational intervention. Overall, approximately 65% of naïve-CE dogs developed normal fecal consistency after four weeks, underscoring the direct impact of hydrolyzed diets on symptom resolution even when other treatments were used alongside. 

Among dogs previously classified as NRE—those that had failed earlier diet, antibiotic, and immunomodulatory trials—a reassessment of diet led to notable clinical improvements. Although over half of these dogs had normal protein levels (excluding ongoing PLE) and histopathology was available for only half, specialists opted for further dietary changes. In more than two-thirds of NRE cases, switching exclusively to an alternative diet (most often a different hydrolyzed formula, although some received home-cooked or highly digestible options) was sufficient to lower the total Canine Inflammatory Bowel Disease Activity Index (CIBDAI). This suggests that many dogs labeled NRE may in fact be difficult-to-manage FRE cases that simply required a different diet. For the remaining one-third, diet changes accompanied by adjustments to immunomodulatory or supportive therapies were undertaken; although detailed follow-up data were lacking, existing literature supports that diet remains a crucial component even in multimodal regimens. 

Because this study was retrospective, its findings are subject to several limitations. Clinical improvement was assessed primarily through owner‐reported stool consistency and CIBDAI scores, introducing subjective bias. In naïve-CE dogs, only fecal consistency could be reliably extracted from records, whereas in NRE cases, the absence of consistent histologic data meant that occult neoplasia or infection could not be definitively ruled out. Owner compliance with strict dietary regimens may also have influenced outcomes. Moreover, concurrent treatments make it difficult to attribute improvements solely to diet. Despite these caveats, most dogs in both groups demonstrated improved fecal consistency or CIBDAI scores following diet transition. 

In conclusion, this study emphasizes that dietary management—especially the implementation or reassessment of hydrolyzed and other elimination diets—is central to treating canine CE. For dogs never previously trialed on hydrolyzed diets, dietary change alone produced significant clinical improvement in nearly all naïve-CE cases. Even in dogs classified as NRE, switching to an alternative diet led to marked reductions in disease activity for two-thirds of cases. These results support dietary intervention not only as a first-line therapy but also as a crucial rescue strategy in cases deemed non-responsive to initial treatments. 

Rodrigues, S.D., Mendoza, B., Dias, M.J., Santos, N.S., Hebert, M., Bettin, E., Signorelli, F., Procoli, F., Hernandez, J. and Leal, R.O. (2025), Association of Diet With Treatment Response in Dogs With Chronic Enteropathy: A Retrospective Multicenter Study. J Vet Intern Med, 39: e70071. https://doi.org/10.1111/jvim.70071 

Bottom line — Pretty effective.

Slow Feeders for Horses

This study surveyed 963 current users of slow-feeding systems—both private horse owners and professional yard operators—from Belgium, France, and Switzerland between June 2020 and May 2022, gathering 1,425 individual horse records. The questionnaire probed demographic and management characteristics, types of feeders employed, motivations for use, and any associated issues. Data were analyzed descriptively and with chi-square and linear models to explore associations between user profiles, feeder types and reported outcomes. 

Most respondents had begun using slow-feeders within the last five years, with operators tending to adopt them earlier than private owners. Nets dominated the market, especially those covering hay racks or bales, which operators found time-efficient and owners favored for reducing waste. Hanging high-vertical nets—common in research but less so in practice—were disproportionately linked to workload increases and a higher incidence of reported problems. Plastic and metal dispensers were rare among owners, though Swiss participants used them more often, possibly reflecting their higher proportion of shod horses and concern over nets snagging hooves. 

Horses managed on slow-feeding systems averaged 12.9 years of age, were predominantly warmbloods, and spent most of their time in outdoor group housing with daily turnout. Over half received hay ad libitum, and three-quarters were ridden only for leisur,e less than once per week, illustrating a low-workload profile. Roughly a quarter of these horses were reported as overweight, a motivating factor for many users who sought better weight control without compromising feeding time or gastric health. Despite theoretical concerns about dental damage, postural strain, or increased stereotypies, fewer than 8 percent of respondents reported any health problems or accidents related to slow-feeders. 

The findings highlight a user population inclined toward alternative, welfare-oriented management—older, lightly worked horses in group turnout environments—and underscore the importance of selecting feeder designs that match both caretaker priorities and individual horse needs. Because covering nets are underrepresented in experimental studies despite their widespread use and favorable time-saving profile, future research should evaluate their behavioral and physiological impacts. Careful sampling to reflect the field population and comparative studies across different equestrian cultures will be essential to validate slow-feeding as a broadly applicable tool for enhancing equine welfare. 

M. Roig-Pons, I. Bachmann, S. Briefer Freymond, Slow-feeding dispensers for horses: Who, how and why?, Journal of Veterinary Behavior, Volume 79, 2025, Pages 7-18, ISSN 1558-7878, https://doi.org/10.1016/j.jveb.2025.01.006. 

Bottom line — Potentially useful for screening working dogs.

Just putting things in perspective …