The effects of diets with different starch sources on the total tract apparent digestibility and glucose and insulin responses in cats were investigated. Six experimental diets consisting of 35% starch were extruded, each containing one of the following ingredients: cassava flour, brewers rice, corn, sorghum, peas, or lentils. The experiment was carried out on 36 cats with 6 replications per diet in a completely randomized block design. The brewers rice diet offered greater DM, OM, and GE digestibility than the sorghum, corn, lentil, and pea diets (P < 0.05). For starch digestibility, the brewers rice diet had greater values (98.6%) than the sorghum (93.9%), lentil (95.2%), and pea (96.3%) diets (P < 0.05); however, starch digestibility was >93% for all the diets, proving that despite the low carbohydrate content of carnivorous diets, cats can efficiently digest this nutrient when it is properly processed into kibble. Mean and maximum glucose concentration and area under the glucose curve were greater for the corn-based diet than the cassava flour, sorghum, lentil, and pea diets (P < 0.05). The corn-based diets led to greater values for the mean glucose incremental concentration (10.2 mg/dL), maximum glucose incremental concentration (24.8 mg/dL), and area under the incremental glucose curve (185.5 mg.dL(-1).h(-1)) than the lentil diet (2.9 mg/dL, 3.1 mg/dL, and -40.4 mg.dL(-1).h(-1), respectively; P < 0.05). When compared with baseline values, only the corn diet stimulated an increase in the glucose response, occurring at 4 and 10 h postmeal (P < 0.05). The corn-based diet resulted in greater values for maximum incremental insulin concentration and area under the incremental insulin curve than the lentil-based diet (P < 0.05). However, plasma insulin concentrations rose in relation to the basal values for cats fed corn, sorghum, pea, and brewers rice diets (P < 0.05). Variations in diet digestibility and postprandial response can be explained by differences in the chemical composition of the starch source, including fiber content and granule structure, and also differences in the chemical compositions of the diets. The data suggest that starch has less of an effect on the cat postprandial glucose and insulin responses than on those of dogs and humans. This can be explained by the metabolic peculiarities of felines, which may slow and prolong starch digestion and absorption, leading to the delayed, less pronounced effects on their blood responses.

The success of a weight loss program for pets depends on the owners collaboration. Their compliance is fundamental in establishing the correct food management. The objective of this study was to compare the effectiveness of a weight loss program in two groups of dogs, one maintained under experimental conditions and the other with their owners. The same hypocaloric food was used to feed all animals, the amount being restricted to 60% of the estimated maintenance energy requirement for a 15% reduction of the present body weight of the dog. The animals were followed during 90 days. A standard questionnaire was used to study the owners' perception of obesity and its treatment. The protocol and the diet were found to be effective. The control dogs had an average weight loss of 1.39% per week. Dogs with owners lost on average 0.75% of their body weight per week, a statistically lower result (P<0.05), suggesting that the owners did not follow the treatment closely. The owners were clearly satisfied with the results that were obtained, even with this modest weight loss. The questionnaires were shown to be an important tool in determining the causes of canine obesity, as well as in the follow-up of the treatment.

The influence of rice, maize, and sorghum raw material particle size in extruded dry dog food on the digestibility of nutrients and energy and the fecal concentration of fermentation products was investigated. Three diets with similar nutrient compositions were formulated, each with 1 starch source. Before incorporation into diets, the cereals were ground into 3 different particle sizes (approximately 300, 450, and 600 µm); therefore, a total of 9 diets were in a 3 × 3 factorial arrangement (3 cereals and 3 particle sizes). Fifty-four beagle dogs (12.0 ± 0.1 kg BW) were randomly assigned to the diets, with 6 dogs per diet. The digestibility was measured with the chromium oxide method. The data were evaluated with ANOVA considering the carbohydrate source, grinding effect, and interactions. The means were compared with the Tukey test and polynomial contrasts (P < 0.05). With the same grinding procedure, rice was reduced to smaller particles than other cereals. The cereal mean geometric diameter (MGD) was directly related to starch gelatinization (SG) during extrusion. For rice diets, the MGD and SG did not change nutrient digestibility (P > 0.05); only GE digestibility was reduced at the largest MGD (P < 0.01). For maize and sorghum diets, the total tract apparent nutrient digestibility was reduced for foods with greater MGD and less SG (P < 0.01). A linear reduction in nutrient digestibility according to cereal particle size was observed for sorghum (r2 < 0.72; P < 0.01). Higher concentrations of fecal total short-chain fatty acids (SCFA) were observed for sorghum diets (P < 0.05) than for other diets. The rice diets led to the production of feces with less lactate (P < 0.05). The increase in raw material MGD did not influence fecal SCFA for rice diets, but for the dogs fed maize and sorghum foods, an increase in propionate and butyrate concentrations were observed as MGD increased (P < 0.05). In conclusion, for dogs fed different particle sizes of the cereal starches in the extruded diets, the digestibility and fecal characteristics were affected, and this effect was ingredient dependent.

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A modificação dietética tem sido estudada e empregada no controle e prevenção da Doença do Trato Urinário Inferior dos Felinos. Este trabalho estudou a influência do teor de água e da digestibilidade das rações sobre a ingestão, excreção urinária e excreção fecal de água. Utilizaram-se 10 gatas adultas castradas, alojadas em gaiolas metabólicas.Testaram-se quatro tratamentos: ração enlatada; seca super-premium; seca econômica e seca econômica acrescida de 50% de água. Determinou-se a ingestão de água via alimento e bebedouro, a excreção de água via fezes e urina e o coeficiente de digestibilidade das rações. Foi empregado um quadrado latino com repetições no tempo. Os resultados foram avaliados por análise de variância seguido pelo teste de Tukey para a comparação de médias e a Correlação de Pearson para se verificar a associação entre variáveis (p<0,05). O consumo de ração enlatada proporcionou uma maior ingestão total de água e uma maior excreção de urina, que apresentou menor densidade. Os gatos compensaram a maior ingestão de água alimentar bebendo menos água. Quanto menor a ingestão de matéria seca e maior a digestibilidade do alimento, menor a excreção fecal de água, pois as rações secas de baixa e alta digestibilidade obtiveram, respectivamente, relação excreção de urina:excreção de água fecal de 0,7:1 e 1,6:1. A ingestão de gordura apresentou correlação positiva com o volume urinário. Rações de maior digestibilidade promovem menor perda fecal de água, mas somente a ração enlatada (alta relação água:matéria seca) proporcionou maiores ingestão total de água e volume urinário.