Raw mechanically separated chicken meat and salmon protein hydrolysate as protein sources in extruded dog food: effect on protein and amino acid digestibility.

Protein quality was evaluated for mechanically separated chicken meat (MSC) and salmon protein hydrolysate (SPH), and for extruded dog foods where MSC or SPH partially replaced poultry meal (PM). Apparent total tract digestibility (ATTD) of crude protein (CP) and amino acids (AA) in the protein ingredients and extruded foods was determined with mink (Neovison vison). The extruded dog foods included a control diet with protein from PM and grain, and two diets where MSC or SPH provided 25% of the dietary CP. Nutrient composition of the protein ingredients varied, dry matter (DM) was 944.0, 358.0 and 597.4 g/kg, CP was 670.7, 421.2 and 868.9 g/kg DM, crude fat was 141.4, 547.8 and 18.5 g/kg DM and ash was 126.4, 32.1 and 107.0 g/kg DM for PM, MSC and SPH respectively. The content of essential AA (g/100 g CP) was more than 10.0 percentage units lower in SPH than in PM and MSC. The ATTD of CP differed (p < 0.001) between protein ingredients and was 80.9%, 88.2% and 91.3% for PM, MSC and SPH respectively. The ATTD of total AA was lowest (p < 0.001) for PM, and similar (p > 0.05) for MSC and SPH. In the extruded diets, the expected higher ATTD of CP and AA from replacement of PM with MSC or SPH was not observed. The ATTD of CP was determined to be 80.3%, 81.3% and 79.0% for the PM, MSC and SPH extruded foods respectively. Furthermore, the ATTD of several AA was numerically highest for the PM diet. Possibly, extrusion affected ATTD of the diets differently due to different properties and previous processing of the three protein ingredients.

Protein and amino acid bioavailability of extruded dog food with protein meals of different quality using growing mink () as a model.

The present study evaluated growing mink () as a model for dietary protein quality assessment of protein meals used in extruded dog foods. Three foods with similar CP content but of different protein quality were produced using different protein meals. The protein meals varied with respect to CP digestibility and AA composition and included lamb meal (LBM), poultry meal (PM), and fish meal (FM) with low, intermediate, and high protein quality, respectively. Nitrogen balance, BW gain, protein efficiency ratio (PER), and apparent total tract digestibility (ATTD) were used as measures of protein and AA bioavailability in growing mink. Standardized ileal digestibility (SID) was used to measure protein and AA bioavailability in adult dogs (). The mink study (3 × 3 Latin square design) included 12 kits aged 8 to 11 wk. The dog study included 12 dogs divided in 3 groups allocated to 1 of the experimental diets. The growing mink responded in accordance with the different AA supply between diets, as determined by the first limiting AA. The LBM diet deviated from the other diets with lower ( < 0.001) values for N retention, BW gain, and PER, and the diets differed ( < 0.001) in ATTD of CP and all AA, except for hydroxyproline. Retention of N was 0.66, 1.04, and 1.18 g·kg·d; BW gain was 8.2, 26.8, and 35.3 g/d; PER was 0.38, 1.39, and 1.71; and ATTD of CP was 66.8, 73.8, and 82.1% for the LBM, PM, and FM diets, respectively. In dogs, SID of CP and AA differed ( ≤ 0.017) between diets and was generally lowest for the LBM diet, intermediate for the PM diet, and greatest for the FM diet. For CP, SID was 71.5, 80.2, and 87.0% for the LBM, PM, and FM diets, respectively. The contents of digestible CP and AA (based on SID) covered the minimal requirement for adult dogs set by the NRC for all diets, except for the content of digestible Met + Cys in the LBM diet. Despite this, dietary content of Met + Cys in the LBM diet agreed with the recommended level set by the NRC and the Association of American Feed Control Officials for adult dogs but was below the level recommended by the European Pet Food Industry Federation. It was concluded that growth studies with mink kits can provide valuable information in protein quality assessment of extruded dog foods. Furthermore, the study showed that to ensure nutritional adequacy of dog food and to be able to compare protein quality of dog foods, information on AA composition and digestibility is crucial.

Raw beef bones as chewing items to reduce dental calculus in Beagle dogs.

OBJECTIVE: Evaluate the effect of raw bovine cortical bone (CB) (medullary bone cross-sectioned) and marrow or epiphyseal 'spongy' bone (SB) as chew items to reduce dental calculus in adult dogs. METHODS: Eight 3-year-old Beagle dogs were observed in two study periods. In the first study, the dogs each received a piece of bovine femur CB (122 ± 17 g) daily and in the second study, a piece of bovine femur SB (235 ± 27 g). The first study lasted 12 days and the second 20 days. Dental calculus was evaluated using image integration software. RESULTS: At the start of the studies, dental calculus covered 42.0% and 38.6% of the dental arcade areas, respectively. In study one, the chewing reduced the established dental calculus area to 27.1% (35.5% reduction) after 3 days and after 12 days the dental calculus covering was reduced to 12.3% (70.6% reduction). In study two, the dental calculus covered 16.8% (56.5% reduction) after 3 days, 7.1% (81.6% reduction) after 12 days and 4.7% (87.8% reduction) after 20 days. The CB remained largely intact after 24 h, but SB was reduced to smaller pieces and in some cases totally consumed after 24 h. No complications such as tooth fractures, pieces of bone stuck between teeth or intestinal obstructions were observed during the studies. CONCLUSIONS: Chewing raw bovine bones was an effective method of removing dental calculus in dogs. The SB bones removed dental calculus more efficiently in the short term.

Yttrium oxide (Y2O3) as an inert marker in digestibility studies with dogs, blue foxes and mink fed diets containing different protein sources.

The study evaluated the use of yttrium oxide (Y(2)O(3)) as an inert marker in studies of apparent total tract digestibility in dogs, blue foxes and mink. Comparison was made with total faecal collection, and use of chromic oxide (Cr(2)O(3)) as marker respectively. Four experimental diets were added 0.1 g/kg yttrium oxide and 10 g/kg chromic oxide and fed to four animals of each species. Faecal recovery of yttrium oxide was 94.4% (SEM +/- 1.0), and of chromic oxide 105.8% (SEM +/- 1.5). The digestibilities of dry matter, crude protein, crude fat, starch and total carbohydrates obtained by total collection and yttrium oxide as marker showed close similarity, and in most cases not significant differences, independent of species and diets. In dogs, overall digestibilities of main nutrients with chromic oxide as marker were not significantly different from overall means obtained with yttrium oxide (p > 0.05). Overall digestibility of dry matter, crude protein and total carbohydrates in blue foxes and mink was significantly higher with chromic oxide than with yttrium oxide (p < 0.05). In dogs and blue foxes, digestibilities of individual amino acids determined by use of yttrium oxide were not different from values obtained using total collection of faeces, both within diets and for overall mean (p > 0.05). Overall amino acid digestibilities in dogs determined with chromic oxide as marker were similar to corresponding figures for yttrium oxide, whereas use of chromic oxide resulted in significantly higher digestibilites for a number of amino acids compared with yttrium oxide in foxes and mink (p < 0.05). The digestibilities of most main nutrients and amino acids revealed no interaction between diet and method (p > 0.05). The study showed that yttrium oxide can be used in low concentration in the feed, and allows high accuracy of analyses and thereby precise digestibility determination. It is concluded that yttrium oxide is an alternative inert marker to chromic oxide in the studied species.

Milk intake in blue fox (Alopex lagopus) and silver fox (Vulpes vulpes) cubs in the early suckling period.

Milk intake of fox cubs (2-16 days of age; body weight, 96-649 g) in ten blue fox litters and ten silver fox litters were measured by the water isotope dilution (WID) technique following a single intraperitoneal injection of tritiated water (3HHO). Litter size varied from four to 14 in blue foxes and from three to eight in silver foxes. Silver fox cubs had higher birth weights than blue foxes. Inter-species body weights and growth rates were apparently dependent on litter size and the dam's constitution. In both species growth rate increased with age and body weight (7-35 g per day). In the cubs, the biological half-life of body water turnover (BWT) rose from 1.5 days at 2-3 days of age to 2.5 days at 13-16 days of age, although a considerable scatter was seen. The mean daily milk intake of the cubs varied with body weight, from 31 to 193 g per day, whereas daily milk intake per unit of body mass remained stable at 30-35 g per 100 g body weight. The ratio of milk intake to body weight gain varied considerably among cubs, averaging 4.5 g/g during the 3-week experimental period. In suckling fox cubs, the calculated daily intake of metabolically energy (ME) corresponded fairly with the estimated energy requirements for growth and maintenance of the young. Finally, the applicability and the accuracy of the WID technique was evaluated in ten 3-week-old fox cubs, by tube-feeding with a milk replacer for 48 h, which documented that the daily rates of milk intake and water turnover can be accurately measured in suckling fox cubs by the WID technique following a single injection of 3HHO.

Liver fatty acid composition and peroxisomal fatty acid oxidase activity in blue foxes (Alopex lagopus) and mink (Mustela vison) fed diets containing different levels of fish oil.

At the time of pelting (Nov.), blue foxes had a lower liver lipid content (4-5%) than mink (7-10%), whereas the phospholipid (PL) content was 0.5-1% in both species. Dietary fat content had little influence on total liver fat content but affected the liver fatty acid composition. Levels of n3 fatty acids were higher in the PL fraction than in the remaining fraction of liver lipids in both species. Because PL accounted for a larger part of the total liver lipids in blue foxes than in mink, the proportion of the total liver lipids accounted for by n3 fatty acids was highest in blue foxes. On the other hand, the mink and foxes had about the same quantity of n3 per gram liver owing to higher fat content of mink liver. Analyses of liver lipid fatty acid composition did not reveal any differences between the species in their ability to metabolize n3 fatty acids originating from fish oil. Peroxisomal beta-oxidation activity in the liver was significantly higher in blue foxes than in mink. For both species the total activity rose as the level of dietary fish oil increased.