Apparent total tract energy and macronutrient digestibility of one- to three-day-old, adult ground, extruded, and canned chicken-based diets in domestic cats (Felis silvestris catus)

Beneficial effects of a prescription home-prepared diet and of zucchini on urine calcium oxalate supersaturation and urinary parameters in adult cats

OBJECTIVES

From the authors' experience, the consumption of a balanced prescription home-prepared diet that includes zucchini (courgette) benefits cats with recurrent urolithiasis, but there is no published evidence to support this. The aim was to study the effects on urinary parameters of (1) a balanced prescription home-prepared diet containing zucchini, and (2) the addition of zucchini to a dry food, compared with two commercial therapeutic diets.

METHODS

Eight healthy cats were included in a Latin-square designed protocol. Five diets were evaluated: two commercial diets, designed for cats with urinary disorders, one high-moisture (U-WET) and one high-sodium dry (U-DRY); one home-prepared diet (HOME); one commercial dry food for adult maintenance (DRY); and DRY given together with 10 g of zucchini per kg body weight (DRY-Zuc). After a 7-day adaptation period, urine was collected and daily food and water intakes were assessed for 12 days. Urinary parameters, and relative supersaturation (RSS) for calcium oxalate (CaOx) and struvite, were determined. Data underwent repeated measures ANOVA analysis.

RESULTS

The digestibility of energy, dry matter, protein and fat was highest with the HOME diet. CaOx RSS was lowest in cats eating the HOME diet, but not significantly different from the U-WET or U-DRY diets. CaOx RSS was lower in cats eating the DRY-Zuc diet than in cats eating the DRY diet. Struvite RSS did not differ significantly among groups.

CONCLUSIONS AND RELEVANCE

This study shows that a balanced prescription home-prepared diet was safe and allowed a very low urinary CaOx RSS. It also showed that adding zucchini to dry food lowered the urine CaOx RSS.

Commercial vs Homemade Cat Diets: What you need to know

PRACTICAL RELEVANCE

A feeding plan recommendation for cats, both healthy and with disease, should include diet choice, amounts to feed and the feeding method. Diet choice can be complex owing to the abundance of products, sometimes with conflicting marketing messages, and the prevalence of information with no scientific basis. It is important to be aware of the specific challenges of both commercial and homemade diets. Moreover, a nutritional assessment is a prerequisite when recommending a diet to ensure that it is safe, appropriate for the cat's life stage and nutritious for long-term feeding.

COMMERCIAL VS HOMEMADE DIETS

There are a variety of commercial diets available, allowing considerable customisation. These products are regulated and can be tested to determine nutritional adequacy and safety, although as the industry is partly self-regulated, choice of manufacturer is important. Properly formulated homemade diets can be customised to the patient and are a good option when no commercial product that meets the patient's needs exists. Homemade diets can be an owner preference. A serious limitation is the lack of testing, potentially affecting safety and also resulting in a reliance on database information to determine nutritional adequacy. Generic homemade diet recipes (eg, sourced from the internet) have additional risks of deficiencies and imbalances, and are not recommended. Homemade diets should be devised by a veterinary nutrition specialist with consideration of both patient and owner factors.

CLINICAL CHALLENGES

Dietary misinformation, which is all too readily available on the internet, may result in owners making questionable feeding choices for their pets. A homemade diet may be requested by owners based on the perception that there are poor ingredients in commercial foods. The veterinary healthcare team needs to have good evidence-based information to present to owners about diet choice.

EVIDENCE BASE

Several decades of research on feline nutrition forms the basis for nutritional requirements and dietary recommendations. There are varying degrees of evidence regarding requirements for each nutrient, and a lack of data on the effects of different types of processing on nutrient needs.

Digestible Energy Intake and Digestive Efficiency of Human-Managed North American River Otters (Lontra canadensis)

Diets currently provided to captive North American river otters (Lontra canadensis) are highly variable with different institutions providing various whole foods, commercial complete prepared diets, or combinations of both. This study investigated the digestible energy intake, gastrointestinal transit time, and digestive efficiency of three different diets being fed at three North Carolina institutions. Otters housed at Institution A (n = 3) were fed strictly fish. Otters housed at Institutions B (n = 3) and C (n = 2) were fed a majority fish based diet (58.5 and 74.1%, respectively), supplemented with fruits, vegetables, and supplemental protein sources as enrichment. There was an apparent trend between increased percentage of fish in the diet and faster transit time and higher digestive efficiency. As less fish was included in the diets, the GI transit time was longer (Institution A, 106 minutes; Institution B, 145 minutes; Institution C, 208 minutes). Median digestive efficiency was high for all three groups (A, 91.4%; B, 87.8%; C, 89.8%) but was higher for the institutions feeding fish. Additionally, the overall median gross energy intake for the eight animals in this study was 163.1 kcal/kgBM^0.75/day (range: 92.2 to 260.7 kcal/kgBM^0.75/day). While all three institutions had healthy otter populations, it appears that a higher fish diet should be further studied as the model North American river otter diet.

Effects of weight loss with a moderate-protein, high-fiber diet on body composition, voluntary physical activity, and fecal microbiota of obese cats

OBJECTIVE To determine effects of restriction feeding of a moderate-protein, high-fiber diet on loss of body weight (BW), voluntary physical activity, body composition, and fecal microbiota of overweight cats. ANIMALS 8 neutered male adult cats. PROCEDURES After BW maintenance for 4 weeks (week 0 = last week of baseline period), cats were fed to lose approximately 1.5% of BW/wk for 18 weeks. Food intake (daily), BW (twice per week), body condition score (weekly), body composition (every 4 weeks), serum biochemical analysis (weeks 0, 1, 2, 4, 8, 12, and 16), physical activity (every 6 weeks), and fecal microbiota (weeks 0, 1, 2, 4, 8, 12, and 16) were assessed. RESULTS BW, body condition score, serum triglyceride concentration, and body fat mass and percentage decreased significantly over time. Lean mass decreased significantly at weeks 12 and 16. Energy required to maintain BW was 14% less than National Research Council estimates for overweight cats and 16% more than resting energy requirement estimates. Energy required for weight loss was 11% more, 6% less, and 16% less than American Animal Hospital Association recommendations for weight loss (80% of resting energy requirement) at weeks 1 through 4, 5 through 8, and 9 through 18, respectively. Relative abundance of Actinobacteria increased and Bacteroidetes decreased with weight loss. CONCLUSIONS AND CLINICAL RELEVANCE Restricted feeding of a moderate-protein, high-fiber diet appeared to be a safe and effective means for weight loss in cats. Energy requirements for neutered cats may be overestimated and should be reconsidered.

Are carnivore digestive separation mechanisms revealed on structure-rich diets?: Faecal inconsistency in dogs (Canis familiaris) fed day old chicks

Pronounced variations in faecal consistency have been described anecdotally for some carnivore species fed a structure-rich diet. Typically two faecal consistencies are distinguished, namely hard and firm versus liquid and viscous faeces. It is possible that a separation mechanism is operating in the carnivore digestive tract, as in many herbivore species. Six beagle dogs were fed two experimental diets in a cross-over design of 7 days. Test diets consisted of chunked day old chicks differing only in particle size (fine = 7.8 mm vs coarse = 13 mm) in order to vary dietary structure. Digestive retention time was measured using titanium oxide (TiO2) as marker. The total faecal output was scored for consistency and faecal fermentation profiles were evaluated through faecal short-chain fatty acid (SCFA) and ammonia (NH3) analyses. A total of 181 faecal samples were collected. Dietary particle size did not affect faecal consistency, fermentative end products nor mean retention time (MRT). However, a faecal consistency dichotomy was observed with firm faeces (score 2-2.5) and soft faeces (score 4-4.5) being the most frequently occurring consistencies in an almost alternating pattern in every single dog. Firm and soft faeces differed distinctively in fermentative profiles. Although the structure difference between diets did not affect the faecal dichotomy, feeding whole prey provoked the occurrence of the latter which raises suspicion of a digestive separation mechanism in the canine digestive tract. Further faecal characterisation is however required in order to unravel the underlying mechanism.

Commercially available avian and mammalian whole prey diet items targeted for consumption by managed exotic and domestic pet felines: true metabolizable energy and amino acid digestibility using the precision-fed cecectomized rooster assay

Whole prey diets are commonly used in the zoo and home setting for captive exotic and domestic cats, respectively. Despite their increase in popularity, nutrient digestibility of such diets has been poorly studied. In this study, the precision-fed cecectomized rooster assay was used to determine the protein quality and nitrogen-corrected true ME (TMEn) of 17 whole prey samples (mice [1 to 2 , 10 to 13 , 21 to 25 , 30 to 40 , and 150 to 180 d old], rats [1 to 4, 10 to 13, 21 to 25, 32 to 42, and >60 d old], rabbits [stillborn, 30 to 45 d old, and >65 d old], chicken [1 to 3 d old], and quail [1 to 3, 21 to 40, and >60 d old]) and 2 ground poultry-based products (chicken and duck). Amino acid score (AAS) and protein digestibility corrected AAS (PDCAAS) were calculated using the nutrient profile recommendations for domestic cat food as a reference value (AAFCO, 2012). Average individual indispensable AA (IAA) and total IAA (TIAA) digestibility coefficients were variable anddepended on AA (84 to 94% TIAA, 85 to 95% Arg, 87 to 96% His, 82 to 92% Ile, 84 to 94% Leu, 85 to 93% Lys, 89 to 97% Met, 83 to 94% Phe, 80 to 95% Thr, 84 to 94% Trp, and 80 to 93% Val) and sample. For a majority of the whole prey items, AA concentrations were greater than the Association of American Feed Control Officials ( AAFCO: , 2012) domestic cat nutrient profile recommendations for growth and reproduction and adult maintenance; however, some whole prey had AA concentrations below the AAFCO (2012) recommendations: Met + Cys (1.10% DM) in ground duck (1.06% DM) and taurine (Tau; 0.20% DM) in 30-to-45- and >65-d-old rabbits (0.01 and 0.10% DM, respectively), 150-to-180-d-old mice (0.18% DM), and ground duck (0.15% DM). The TMEn (3.76 to 6.44 kcal/g DM) expressed as the percent of GE (i.e., TMEn/GE) ranged from 66 to 85%, demonstrating how variable the digestibility of these items may be and justifying more research in this area. Both Met and Tau are commonly added to commercial pet foods, so supplements are readily available to address potential deficiencies and improve protein quality. A direct comparison of the ME of whole prey items by in vivo feline and rooster experiments is needed.