Feline obesity is an increasingly prevalent health concern and is closely associated with metabolic disorders and intestinal dysbiosis. This study aimed to screen feline-derived lactic acid bacteria (LAB) for bile salt hydrolase activity, in vitro cholesterol-removal capacity, and selected probiotic-associated characteristics. Approximately 700 LAB isolates were obtained from fecal samples of healthy domestic cats and evaluated for bile salt hydrolase (BSH) activity, among which 105 isolates were identified as BSH-positive. Further screening was performed based on BSH activity, cholesterol-removal capacity, adhesion-related properties, antioxidant activity, gastrointestinal tolerance, antibacterial activity, organic acid production, hemolytic activity, and antibiotic susceptibility. Three candidate strains were ultimately selected and preliminarily identified by 16S rRNA gene sequencing as Enterococcus hirae C283, Ligilactobacillus animalis C289, and Enterococcus faecium C422. These strains exhibited BSH activity and preliminary in vitro cholesterol-removal phenotypes under the tested culture conditions, together with tolerance to simulated gastrointestinal conditions, antioxidant activity, antibacterial activity, and organic acid production. No hemolytic activity was detected; however, all three strains exhibited resistant or intermediate phenotypes to multiple antibiotics, highlighting the need for further genome-based safety assessment, particularly for the two Enterococcus strains. Overall, these findings identified feline-derived LAB candidates with BSH activity, preliminary in vitro cholesterol-removal phenotypes, and multiple probiotic-associated characteristics. However, these in vitro findings do not demonstrate regulation of host lipid metabolism or blood lipid levels. Comprehensive safety assessment, particularly for the Enterococcus strains, and in vivo validation are required before further application.

Enteropathogenic Escherichia coli (EPEC) disrupts intestinal barrier integrity, induces inflammation, and alters gut microbial balance, leading to diarrhea and growth impairment. Probiotics are considered promising alternatives to antibiotics for managing enteric infections, yet the functional properties and underlying mechanisms of feline-derived strains remain unclear. This study evaluated the protective effects of Ligilactobacillus (L.) agilis ZY25 and L. salivarius ZY35, isolated from healthy cats, against EPEC-induced intestinal injury in C57BL/6 mice, with a focus on barrier function, immune modulation, and microbial homeostasis. In this 21-day experiment, 48 mice were assigned to six groups (n = 8/group): control, EPEC model (MOD), chlortetracycline treatment (CTC), probiotic treatment (PRO-T; post-infection only), probiotic pre-treatment (PRO-P; pre-infection only), and continuous probiotic supplementation (PRO; pre- and post-infection). EPEC challenge (0.2 mL; 1 × 10⁹ CFU/mL) was performed daily during experimental days 8–14. EPEC challenge resulted in weight loss (p < 0.05), increased (p < 0.05) diarrhea incidence, elevated (p < 0.05) serum D-lactate, diamine oxidase, and lipopolysaccharide levels, impaired intestinal morphology, immune imbalance, and microbial dysbiosis. Probiotic administration alleviated these alterations, as evidenced by restored intestinal morphology, reduced serum markers of barrier permeability (D-lactate, DAO, LPS), enhanced systemic immunoglobulins (IgA, IgG, IgM), a balanced cytokine profile (increased IL-4, IL-10; decreased TNF-α, IL-6, IL-1β, IFN-γ, CRP), and modulation of the gut microbiota (enrichment of beneficial taxa such as Lachnospiraceae_NK4A136_group and suppression of pro-inflammatory Desulfovibrio). The continuous supplementation regimen (PRO) produced the most consistent improvements among the three intervention strategies tested. These findings suggest that feline-derived probiotics mitigate EPEC-induced intestinal dysfunction, accompanied by improved barrier-related indices, immune rebalancing, and microbial stabilization, thereby providing proof-of-concept evidence for their further evaluation in feline gastrointestinal health.

Feline panleukopenia is a highly contagious and often fatal disease in cats caused by the feline panleukopenia virus (FPV), a member of the Parvoviridae family. Despite the widespread use of vaccination, FPV remains a significant threat to both domestic and wild felid populations worldwide, particularly in young or unvaccinated animals. Effective vaccination strategies are therefore essential for controlling the disease and reducing mortality. Current vaccines, including modified live and inactivated vaccines, have demonstrated substantial efficacy in inducing protective immunity; however, several challenges remain, such as maternal antibody interference, vaccine failure, and safety concerns in certain animal populations. Recent advances in vaccine technology have spurred the development of next-generation FPV vaccines, including recombinant vectors, DNA vaccines, virus-like particle (VLP) vaccines, and novel delivery platforms. Among these, probiotic-based vaccine vectors have garnered growing interest due to their favorable safety profiles, mucosal immunogenicity, and suitability for oral administration. These systems may provide innovative approaches for inducing both systemic and mucosal immune responses against FPV. This review summarizes the current understanding of the immunological mechanisms underlying protection against FPV infection and discusses the progress made in FPV vaccine development. Furthermore, it highlights the major challenges associated with current vaccination strategies and explores emerging vaccine platforms, including probiotic vector-based vaccines, as promising tools for future disease control. Improved vaccine design and optimized immunization strategies will be crucial for enhancing the prevention of feline panleukopenia in the future.

The emotional benefits of pet ownership depend critically on the pet’s physical, behavioural, and cognitive health—all of which can be improved by targeted nutritional interventions that may reduce pain, anxiety, problem behaviours, and cognitive decline. However, almost no studies have tested whether nutrition-induced behavioural improvements translate into measurable gains in owner emotional well-being or relationship satisfaction. It is important to note that the evidence base for cats remains considerably more limited than that for dogs, and many conclusions drawn from canine studies should be extrapolated to cats with caution. Furthermore, the human–animal relationship is bidirectional: owner psychology and feeding practices feed back to affect pet health. This review synthesises evidence across veterinary medicine, nutritional science, and human- animal interaction research to support a central thesis: that the relational value of pet ownership may be a function of pet health, may be modifiable by targeted nutrition, and is hypothesized to be embedded in bidirectional feedback loops that require dyadic interventions. The review explicitly distinguishes between evidence-supported findings and the proposed conceptual framework. The field now requires dyadic randomised controlled trials with co-primary outcomes for both pet and owner, plus precision stratification, pragmatic effectiveness studies, mechanistic biomarkers, and one health approaches. Closing this translational gap requires a coordinated research effort focused on designing dyadic interventions that measurably improve the welfare of both pets and their owners.