Effects of dietary macronutrient composition and feeding frequency on fasting and postprandial hormone response in domestic cats

A meta-analysis: dietary carbohydrates do not increase body fat or fasted insulin and glucose in cats

Commercial cat foods contain a greater carbohydrate content, such as nitrogen-free extract (NFE), compared to a typical prey species. This has led to postulations that increased carbohydrate intake is causing a rise in obesity and IR in cats. Studies investigating high-carbohydrate diets on insulin and glucose responses show inconsistent results. A meta-analysis using 16 studies was conducted to elucidate the relationship between NFE content and body fat mass (BFM, n = 9), fasted insulin (n = 12), and fasted glucose concentrations (n = 14). Dietary NFE, fat, and protein content (% metabolizable energy), as well as daily energy intake (DEI), body weight, body condition (lean, obese), and study design metrics were considered as fixed effects in univariate and multivariate models using proc mixed in SAS, treating study as a random effect. Model evaluation was conducted using corrected Akaike Information Criteria, concordance correlation coefficient, and the root mean square prediction error. The best-fitting model for BFM was the interaction between NFE content and DEI, predicting BFM to decrease when NFE content increased as a proportion of the DEI (P < 0.05). From univariate models, fasted insulin was positively associated with BFM and dietary fat content (P < 0.05), whereas an increase in NFE content was associated with a decrease in fasted insulin in a subgroup of studies (n = 6) of only lean cats (P < 0.05). No significance was observed for models predicting fasted glucose from diet or body composition variables (P > 0.05). The results of this meta-analysis indicate that dietary carbohydrates (NFE), included between 2.8% and 57% ME, are not a risk factor for greater BFM, fasted insulin, and glucose concentrations in cats, suggesting that NFE does not pose a risk for feline obesity, IR, or hyperglycemia. However, future studies should consider postprandial responses of insulin and glucose to macronutrient compositions to further investigate the role of dietary carbohydrates on IR in cats, with particular attention to the role of dietary fat, and the role of body condition.

One Health: Circadian Medicine Benefits Both Non-human Animals and Humans Alike

Circadian biology's impact on human physical health and its role in disease development and progression is widely recognized. The forefront of circadian rhythm research now focuses on translational applications to clinical medicine, aiming to enhance disease diagnosis, prognosis, and treatment responses. However, the field of circadian medicine has predominantly concentrated on human healthcare, neglecting its potential for transformative applications in veterinary medicine, thereby overlooking opportunities to improve non-human animal health and welfare. This review consists of three main sections. The first section focuses on the translational potential of circadian medicine into current industry practices of agricultural animals, with a particular emphasis on horses, broiler chickens, and laying hens. The second section delves into the potential applications of circadian medicine in small animal veterinary care, primarily focusing on our companion animals, namely dogs and cats. The final section explores emerging frontiers in circadian medicine, encompassing aquaculture, veterinary hospital care, and non-human animal welfare and concludes with the integration of One Health principles. In summary, circadian medicine represents a highly promising field of medicine that holds the potential to significantly enhance the clinical care and overall health of all animals, extending its impact beyond human healthcare.

CATastrophic myths part 2: Common misconceptions about the environmental, nutritional, and genetic management of domestic cats and their welfare implications

Despite the cat's popularity as a companion species, many owners and practitioners lack high quality information about important aspects of their behavior and management. Myths, anecdotes, and narratives of cats as 'low maintenance, self-sufficient' animals are pervasive, and the degree to which these may underlie complacency about fully meeting cats' needs is unknown. Several studies suggest that cat welfare and the human-cat bond may benefit from improved education about how to optimize the domestic cat's management and husbandry needs in homes and elsewhere. This paper is the second of a two-part series addressing common myths about cats. The purpose of this paper is to review and debunk common misconceptions about optimal cat care, feeding behavior, genetics, and training. Replacing these misconceptions with scientifically generated information could have a significant impact on the behavioral management of cats, positively influencing their physical health, mental stimulation, and well-being, and reducing stress for both cats and the people caring for them. Areas where further research is required to address ambiguities, and to better meet cats' needs in homes and other environments, are also identified.

The daytime feeding frequency affects appetite-regulating hormones, amino acids, physical activity, and respiratory quotient, but not energy expenditure, in adult cats fed regimens for 21 days

The effects of feeding frequency on postprandial response of circulating appetite-regulating hormones, insulin, glucose and amino acids, and on physical activity, energy expenditure, and respiratory quotient were studied in healthy adult cats. Two experiments were designed as a 2 x 3 replicated incomplete Latin square design. Eight cats, with an average body weight (BW) of 4.34 kg ± 0.04 and body condition score (BCS) of 5.4 ± 1.4 (9 point scale), were fed isocaloric amounts of a commercial adult maintenance canned cat food either once (0800 h) or four times daily (0800 h, 1130 h, 1500 h, 1830 h). Study 1 consisted of three 21-d periods. On day 14, two fasted and 11 postprandial blood samples were collected over 24 hours to measure plasma concentrations of ghrelin, GLP-1, GIP, leptin, PYY, insulin and amino acids, and whole blood glucose. Physical activity was monitored from day 15 to 21 of each period. In Study 2 indirect calorimetry was performed on the last day of each period. Body weight was measured weekly and feed intake recorded daily in both experiments. No effect of feeding regimen on BW was detected. Cats eating four times daily had lesser plasma concentrations of GIP and GLP-1 (P<0.05) and tended to have lesser plasma PYY concentrations (P<0.1). Plasma leptin and whole blood glucose concentrations did not differ between regimens (P>0.1). Cats fed once daily had a greater postprandial plasma amino acid response, and greater plasma ghrelin and insulin concentrations (P<0.05). Physical activity was greater in cats fed four times (P<0.05), though energy expenditure was similar between treatments at fasting and in postprandial phases. Finally, cats eating one meal had a lower fasting respiratory quotient (P<0.05). Overall, these data indicate that feeding once a day may be a beneficial feeding management strategy for indoor cats to promote satiation and lean body mass.

Understanding the Nutritional Needs of Healthy Cats and Those with Diet-Sensitive Conditions

Diets for cats must provide complete nutrition and meet the needs of the individual patient. There is no single diet that is perfect for all cats, and veterinarians must consider the needs of the cat as well as the preferences of the owners when making dietary recommendations. This article focuses on the interface between animal factors and nutritional needs in cats and is divided into 3 sections. Section 1 addresses the dietary needs of healthy cats, including differences among life stages. Section 2 addresses common myths regarding feline nutrition. Section 3 addresses common nutrient-sensitive conditions in cats, including sarcopenia of aging.

PANCOSMA COMPARATIVE GUT PHYSIOLOGY SYMPOSIUM: ALL ABOUT APPETITE REGULATION: Effects of diet and gonadal steroids on appetite regulation and food intake of companion animals

The prominent incidence of overweight and obese pet animals not only results in higher morbidity and mortality, but also poses a threat for the quality of life, longevity, and well-being of dogs and cats. To date, strategies to prevent BW gain or to induce weight loss have had modest success in the pet population. In part, due to the complexity and the multifactorial nature of this disease, which involves pet-human interaction, environmental and dietary factors, and an intertwined metabolic process that still is not fully understood. As such, research methods to investigate the role of physiological hormones and dietary management on mechanisms related to the control of feelings of satiety and hunger in pet animals is warranted. Increasing interest exists in exploring gut chemosensing mechanisms, the crosstalk between metabolic-active tissues, and the interface between the gut microbiota and the nervous system (gut-brain axis). The noninvasive nature of research conducted in companion animals focuses on systemic approaches to develop environmental, nutritional, or therapeutic interventions that can be translated from research settings to pet-owned households. Because the majority of the pet population is spayed or neutered, it is important to determine the effect that sex hormones might have on appetite regulation and fasting metabolic rate of these animals. In general, studies have revealed that gonadectomy may establish a new "set point" characterized by increased food intake and BW, accompanied by physiological and behavioral changes. Some studies have also shown associations between gonadectomy and alterations in appetite-related hormones (e.g., ghrelin, leptin, adiponectin, glucagon-like peptide-1). Manipulation of macronutrients in diets of dogs and cats have also been investigated as a mean to improve satiety. Most of the research in this area has focused on high-protein diets, predominantly, for cats, and the use of dietary fiber sources of contrasting fermentability and viscosity profiles. Dietary fibers may affect the production of fermentative end products and gut microbiome, digestive and absorptive processes, appetite-related hormones, and promote "gut fill" and satiety. More recent studies have reported profound effects of dietary manipulation on the phylogeny and functional capacity of gut microbial communities of dogs and cats.

Macronutrients in feline health

Dietary macronutrients include protein, fat, and carbohydrates. Current nutritional recommendations establish minimums but not maximums for protein and fat but not for carbohydrates; thus, commercial feline maintenance diets have a wide range of macronutrient distribution depending on manufacturer, ingredients, and processing. There is growing interest and discussion, however, in defining the ideal macronutrient composition of feline diets to maximize longevity and health. Current recommendations should be tailored to each patient based on age, body condition, presence of muscle mass atrophy, and the presence of disease.

Effects of feeding frequency and dietary water content on voluntary physical activity in healthy adult cats

Low physical activity has been identified as a major risk factor for the development of feline obesity and diabetes. This study aimed to evaluate the effects of increased meal frequency and dietary water content on voluntary physical activity in cats fed to maintain BW. Ten adult lean neutered male cats were used in 2 tests, both crossover studies composed of a 14-d adaptation period, followed by a 7-d measurement of physical activity from d 15 to d 22 using Actical activity collars. Cats were group housed for most of the day, except for times when they were individually housed in cages to access their diet under a 16:8 h light:dark cycle. In Exp. 1, the difference in voluntary physical activity among cats fed 1, 2, 4, or a random number of meals per day were tested in a 4 × 4 Latin square design in 4 individual rooms. In Exp. 2, the effect of increasing dietary water content on voluntary physical activity was tested in a crossover design including a 5-d phase for fecal and urine collection from d 22 to 27. Cats were randomly assigned to 2 rooms and fed a dry commercial diet with or without added water (70% hydrated) twice daily. Activity levels were expressed as "activity counts" per epoch (15 s). In Exp. 1, average daily activity level for 1-meal-fed cats was lower than 4-meal-fed (P = 0.004) and random-meal-fed (P = 0.02) cats, especially during the light period. The activity level of cats during the dark period was greater in 1-meal-fed cats compared with cats fed 2 meals (P = 0.008) or 4 meals (P = 0.007) daily. Two-hour food anticipatory activity (FAA) before scheduled meal times for 1-meal-fed cats was lower (P < 0.001) than for the multiple-meal-fed cats. In Exp. 2, average daily activity level of cats fed the 70% hydrated diet tended to be higher (P = 0.06) than cats fed the dry diet, especially during the dark period (P = 0.007). Two-hour FAA before the afternoon meal for cats fed the 70% hydrated diet was lower (P < 0.05) than for cats fed the dry diet. Cats fed the 70% hydrated diet had greater daily fecal (P = 0.008) and urinary (P = 0.001) outputs and lower (P < 0.001) urinary specific gravity compared to cats fed the dry diet. In conclusion, increased feeding frequency and dietary water content, without changing energy intake or dietary macronutrient composition, appear to promote physical activity, which may aid in weight management in cats.