Guava fibre characterization and effects on digestibility, fermentation products, gastrointestinal transit time and palatability of dry diets for dogs.

The use of fruit fibres as a way of reusing industrial waste is attractive and necessary, increasing the efficiency and reducing the environmental impact of the industry. This study characterized guava fibre as a fibrous ingredient and evaluated its effects when included in extruded diets for dogs on nutrient digestibility, faecal traits, fermentation products, gastrointestinal transit time and palatability. Four diets were formulated: CO (control diet, no fibrous ingredients added), GF3 (3% guava fibre), GF6 (6% guava fibre) and GF12 (12% guava fibre). The guava fibre was added to diets in replacement of maize, with small adjustments in the other ingredients to ensure similar contents of protein and fat. The diets were fed to 24 adult Beagle dogs (6 per diet) during 15 days for adaptation followed by 15 days for assessment of digestibility, fermentation end products and gastrointestinal transit time. The palatability of G6 and G12 treatments was evaluated against the CO by the two-pan test. Results were compared by analysis of variance and polynomial contrasts according to the guava fibre inclusion level (p < 0.05). The addition of guava fibre did not change nutrient intake except for the increase on dietary fibre (p < 0.001). Fibre inclusion resulted in a quadratic reduction in total tract apparent digestibility for dry matter, organic matter, crude protein and crude energy (p < 0.001), and on the metabolizable energy content of the foods (p < 0.001). Guava fibre addition did not change the faecal concentration of ammonia, lactic acid, faecal pH and branched chain fatty acids but it decreased acetic and propionic acids concentration (p < 0.01). The inclusion of 12% guava fibre did result in a faster transit time (p = 0.046) compared to the control diet. Guava fibre can be characterized as a novel insoluble non-fermentable fibre source that could be safely used in levels up to 12% in canine extruded diets.

Effects of crude protein and sodium intake on water turnover in cats fed extruded diets.

The comprehension of strategies to increase urine production may be important, especially in kibble diets to prevent urolithiasis in cats. The effects of increasing amounts of crude protein (CP) and sodium on the water turnover of cats were evaluated using the water balance (WB) method and the deuterium dilution technique. The study followed a randomized block design, with three blocks of eight cats, two cats per food type in each block, and six cats per food. Four extruded diets with different amounts of CP and sodium were evaluated (on DM basis): 28% CP and 0.58% sodium; 39% CP and 0.64% sodium; 52% CP and 0.76% sodium; and 64% CP and 0.87% sodium. Cats were individually housed in cages for 8 days to measure WB, urea excretion, and faecal and urine characteristics. Deuterium oxide was used to evaluate water turnover, and during the period cats were housed in a collective cattery. The data were analysed by an F test, and the means were compared by polynomial contrasts. The ɑ level of significance was set at 0.05. The methods were compared by Pearson correlation, and Bland and Altman analysis. The increase in the CP content elevated linearly the renal excretion of urea (p < .001), and, together with the higher sodium intake, elevated the renal solute load, which resulted in a linear increase in urine production and water intake (p < .01). The urine density, metabolic water, and faecal and insensible water losses did not differ (p > .05). The water flux increased linearly when using the deuterium method (p < .001), but the obtained values were 20.85 ± 11.11 ml/cat/day higher than those verified using the WB method (p = .001). Higher CP and sodium amounts in dry diets increased the urine production and water consumption of cats, and this can be explored as a possible option to increase urination.

Validation of saliva and urine use and sampling time on the doubly labelled water method to measure energy expenditure, body composition and water turnover in male and female cats.

Less invasive protocols are necessary to study energy expenditure (EE) of cats living in homes for expressing their normal living conditions. The present study compared sampling times and the use of saliva, urine and blood to measure 2H and 18O to apply the doubly labelled water method. In the first study, four cats were used to evaluate the enrichment (2, 4, 6, 7 and 8 h) and elimination (2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 d) of 2H and 18O (subcutaneously injected). The maximum enrichment was after 5 h (R2 0·82) of injection, with an Ln linear elimination of both isotopes (P < 0·001; R2 0·99). The results of EE were similar, regardless of the sampling time used (P = 0·999). In the second study, seven male cats and seven female cats were used. Before and after isotope injection (5 h, 7 d, 10 d and 14 d), blood, saliva and urine were collected. Isotope enrichment was lower in urine (P < 0·05) and at the similar level in blood and saliva. Isotope elimination was similar for all fluids (P < 0·473). The EE calculated with blood and saliva was similar but higher for urine (P = 0·015). According to Bland-Altman statistics, blood and saliva presented low bias and high correlation (P < 0·001), but this was not observed for urine (P = 0·096). Higher EE was observed for male cats (384 (se 39) kJ/kg0·67 per d) than for female cats (337 (se 34) kJ/kg0·67 per d; P < 0·05). The sampling time for the method is flexible, and saliva can be used as a substitute for blood.

Feed processing effects on digestibility, palatability, excreta fermentation products and blood parameters in blue-fronted amazon parrots (Amazona aestiva)†.

Captive parrots show a high incidence of obesity and other metabolic disorders due to the consumption of unbalanced diets. Therefore, this study evaluated the digestibility and metabolic effects of transitioning blue-fronted amazons from a high fat diet (sunflower seeds) to processed diets with three degrees of starch gelatinization (SG). The same feed formulation was processed to obtain pelletized feed (PEL) at 27.1% SG; low-cooked extruded feed (EXTL ) at 81.6% SG; and high-cooked extruded feed (EXTH ) at 98.5% SG. Thirty adult parrots were fed sunflower seeds for 90 days, then were distributed in a completely randomized design with 10 repetitions per treatment, and fed one of the three prepared diets for 160 days. Feed palatability, apparent digestibility, excreta concentrations of volatile fatty acids, lactate and ammonia, initial and final radiographic examinations, blood cell counts and glucose, triglycerides, cholesterol, total protein, albumin, aspartate aminotransferase (AST) and uric acid levels were evaluated. The data were analysed by an analysis of variance and compared by Tukey's test (p < 0.05). Sunflower seed was more digestible than processed feeds (p < 0.05). Diet processing interfered with fat and starch digestibility (p < 0.001), being higher in the PEL than in the EXTH and EXTL respectively. Transitioning from sunflower seeds to balanced diets reduced serum glucose, triglycerides, cholesterol and AST (p < 0.05) and increased red blood cell, haemoglobin, lymphocyte, monocyte and leucocyte counts (p < 0.01). Radiographs indicated a decreased hourglass (p = 0.015) and a reduced heart-liver ratio after ingesting the processed feeds (p < 0.05). Feed processing did not affect blood cell counts, serum biochemistry or radiographic examinations. In conclusion, parrots preferred the extruded diet and did not require an extensive SG to properly digest the feed. Consuming the processed diets improved the birds' metabolism and health.