Nine commercial dog foods (7 dry and 2 wet) were analyzed for fatty acid ratios in the C₁₈ group, lipid change (oxidation and iodine value), ascorbic acid, and antioxidants (Butyl hydroxyanisole (BHA) and Dibutyl hydroxytoluene (BHT)).
R1. BHA and BHT were extracted for 2 or 6 hours with the succession extraction method. The 2-hour extraction method has resulted in less contamination and had better results than the conventional 6-hour extraction. The dry dog foods had about 6 times more BHA and BHT than the wet dog foods. However, there was no difference in the amount of BHA and BHT between wet dog food and dry dog food in terms of dry weight. The total of BHA and BHT was 93.9mg/kg in the dog food that had the highest amount of the antioxidants. Among the 9 dog foods, domestically produced ones tended to have lower concentrations of BHA and BHT than the imported ones.
2. The ascorbic acid contents of the nine dog foods were all 2.2g/kg or less. There was no relationship between ascorbic acid content and oxidation value during storage.
3. By analyzing C_18:1, C_18:2, C_18:3, the contents of oleic acid, linolic acid and linoleic acid in the four dog foods were found to be 17.4-32.8%,3.7%-7.5% and 0.6-1.8%, respectively. The lipids of these dog foods were judged to be of good quality, as the content of oleic acid was high.
4. The oxidation value of dog foods was 3.3 immediately after opening of the bags. This value is low enough to be safe for dogs.
5. The iodine values of two dog foods became lower with time after their bags were opened. As the iodine values were smaller than 90, the lipids in the two dog foods were a nondrying oil.
6. The amounts of BHA and BHT in the samples A and B were not high enough to reduce the oxidation value and the iodine value.

View full abstract

Aiming at increasing the production of conjugated linoleic acid (CLA) in the intestine of dogs, the merits of simultaneous utilization of Butyrivibrio fibrisolvens and Bifidobacterium breve as probiotics were examined in vitro. Incubation of B. fibrisolvens with linoleic acid (LA) resulted in little accumulation of CLA because of its high ability to reduce CLA, whereas B. breve accumulated CLA because of its little ability to reduce CLA. However, the growth of B. breve was inhibited possibly due to the toxic effect of LA and CLA. Coculture of B. breve with B. fibrisolvens brought about CLA accumulation and alleviation of the growth inhibition of B. breve. When B. breve and B. fibrisolvens (10: 1) were simultaneously added to the mixed fecal microbes from old dogs at a level of 1% of the total number of bacteria, and then incubated with LA, significant increase in CLA accumulation was observed. These results suggest that simultaneous administration of the two bacteria as probiotics causes a lasting increase in CLA production and accumulation in the intestine of dogs.

View full abstract

To evaluate chicken meal (CM), meat meal (MM) and corn gluten meal (CGM) as a protein source of dry cat food, twelve healthy adult cats (mean body weight; 4.0 kg) were divided into 3 groups of 4cats each, and allotted to 3 dry diets containing CM, MM or CGM as a main protein source in a 3×3 Latin square design with 3 weeks per period. The diets contained about 94% DM; about 31%crude protein (CP) per DM, and the CP from CM, MM or CGM occupied more than 80% of total dietary CP. All cats were allowed to free access to the diets and water. Feces and urine were totally collected during the final 7 days of each experimental period, and digestibility, water balance, nitrogen (N) balance, mineral (Ca, P and Mg) balance, and concentrations of urea, ammonia, creatine and creatinine in urine were determined. Although daily feed intake, water intake and urine volume did not differ among the groups, daily amounts of feces and fecal moisture content were higher (P<0.05) in the CGM group than in the other two groups. Digestibility of DM increased in the order of CGM<CM<MM, and digestibility of CP was higher (P<0.05) in the MM group than in the other two groups. As for water balance, only the fecal water excretion was higher (P<0.05) in the CGM group than in the other two groups. These results suggest that fecal water excretion increased with an increase of fecal DM excretion in the CGM group, in which DM digestibility was lowest among the three groups. Percentage proportion of absorbed N to N intake was higher (P<0.05) in the MM group than in the other two groups, and the utilization efficiency of N intake or N absorbed in the CM group was intermediate between the highest MM group and the lowest CGM group. In addition, proportion of ammonia N to the total urinary N was higher (P<0.05) in CM and CGM groups than in MM group, and that of creatinine N increased in the order of CGM<CM<MM. Utilization efficiency of P tended to be lowest in the CM group, although no difference was detected in that of Ca and Mg among the groups.

View full abstract

Capacity to form struvite crystals in urine of adult cats was compared among dry diets containing chicken meal (CM), meat meal (MM) or corn gluten meal (CGM) as a main protein source. Twelve healthy cats (mean body weight; 4.0 kg) were divided into 3 groups of 4 animals each, and allotted to the 3 diets in a 3×3 Latin square design with 3 weeks per period. Contents of Ca, P, and methionine (Met) in the diets were adjusted by adding adequate amounts of Ca(PO4)2, CaCO3 and D, L-Met, because CM contained excessive amounts of Ca and P, and CGM contained a high level of Met. Every diet contained about 31% crude protein (CP) per DM, and cats were allowed to free access to the diets and water throughout the experiment. Urine was totally collected during the final 7 days of each experimental period to determine urine volume, pH, negative logarithm of struvite activity products (pSAP), number of struvite crystals in urine, and the HCl-insoluble fraction of urine centrifugal sediment as an index of insoluble organic component in urine. Urinary pH and the number of struvite crystals were determined using fresh urine. Urine volume did not differ among the groups, but urine pH differed (P<0.05) and increased in the order of CGM<CM<MM. However, urine pH exceeded 7.0 even in the CGM group. The value of pSAP was higher (P<0.05) in the CGM group, and significant difference was not detected between CM and MM groups. This result indicated that CM and MM groups were more liable to form struvite crystals and, in fact, the number of struvite crystals in urine was higher (P<0.05) in the CM and MM groups than in the CGM group. Proportion of HCl-insoluble fraction to the urine centrifugal sediment was lower (P<0.05) in the CM group than in the other two groups. In summing up, the CM has a limit as a protein source of dry cat food, because it contains excessive amounts of Ca and P, and is apt to alkalize urine.

View full abstract