Identification of metabolites in plasma and urine of Uruguayan propolis-treated rats

Propolis is a resinous substance collected by honeybees from various plant sources. It is extensively used in food and beverages to improve health and prevent diseases such as heart disease, diabetes, and cancer. To investigate the absorption and metabolism of the components in propolis, in the present study, we administered ethanol extracts of Uruguayan propolis (poplar type propolis) orally to rats and analyzed their plasma and urine by high-performance liquid chromatography with photodiode array and mass spectrometric detection. After deconjugation of the components by beta-glucuronidase/sulfatase treatment of the specimen, pinobanksin 5-methyl ether, pinobanksin, kaempferol, chrysin, pinocembrin, and galangin were detected in plasma of rats orally administered propolis. These compounds were detected also in urine after beta-glucuronidase/sulfatase treatment. Furthermore, pinobanksin 5-methyl ether, pinobanksin, chrysin, pinocembrin, and galangin were present in the urine also in free form. These results suggest that flavonoids in propolis are metabolized and circulate in the body after oral administration of propolis.     

Ammonia production from uric acid and its absorption from the caecum of the cockerel

1. Experiments were done in vitro and in situ in the caeca to measure ammonia production from uric acid and its absorption. 2. When uric acid was introduced into a caecal sac containing mixed caecal micro-organisms 0.77 disappeared in 1 h, with the concomitant appearance of ammonia. 3. Amounts of ammonia produced from added [15N] uric acid in the caeca in situ after 30 min and in caecal medium in vitro after 10 h, were 0.28 and 0.25 respectively of the added 15N. 4. About 0.92 of the ammonia introduced into a caecal sac disappeared from the lumen fluid in 30 min. 5. It is concluded that ammonia is produced from uric acid by caecal micro-organisms and rapidly absorbed.     

Effect of colostomy on the occurrence of dietary [15N]urea in intestinal contents,blood, urine and tissues in chickens fed a low protein diet plus urea

1. The occurrence of ¹⁵N was examined in excreta for 10 h, and in intestinal contents, blood and tissues at 10 h after [¹⁵N]urea was fed to conventional and colostomised cockerels.

2. Total‐¹⁵N excretion and ¹⁵N‐balance in control chickens were 18.88 and 44.79 mg/kg body weight/10 h), respectively. The former was increased and the latter was decreased by colostomy by 10.75 mg (P<0.01).

3. Amounts of [¹⁵N]urea, [¹⁵N]ammonia and [¹⁵N]uric acid excreted by control birds were 13.78, 3.90 and 0.18 mg/kg body weight/10 h or 0.73, 0.21 and 0.01 of the total‐¹⁵N excreted respectively.

4. The [¹⁵N]urea, [¹⁵N]uric acid and total‐¹⁵N excreted were all increased after colostomy but [¹⁵N]ammonia was decreased (uric acid P<0.05, others P<0.01). The increase in total‐¹⁵N was mostly accounted for by [¹⁵N]urea.

5. Colostomy resulted in significantly less total‐¹⁵N in the contents of the whole intestine (P<0.01), less total‐¹⁵N, [¹⁵N]ammonia and [¹⁵N]urea in the contents of the co!o‐rectum (P<0.01) and less total‐¹⁵N and [¹⁵N]urea in the contents of the upper intestine (P< 0.05); it did not affect any in caecal contents.

6. [¹⁵N]Urea in blood, liver and kidney (blood P<0.01, others P< 0.05), and [¹⁵N]glutamine amide (P< 0.05) and [¹⁵N]uric acid (P< 0.01) in blood were significantly decreased after colostomy.

7. The results support the hypothesis that most of the dietary urea is utilised as the result of a back‐flow of ureteral urea into the caeca where it is rapidly converted into ammonia which is then metabolised to other compounds.     

Role of caeca in the nitrogen nutrition of the chicken fed on a moderate protein diet or a low rotein diet plus urea

1. A study was carried out to investigate whether the back‐flow of urine into the caeca benefits the nitrogen economy of adult cockerels fed on a diet containing 100 g protein/kg and when dietary urea is absorbed, excreted into urine and utilised.

2. No significant effects of colostomy on nitrogen utilisation were observed in chickens fed on 100 g/kg protein diet, whereas colostomy was highly effective in decreasing it in chickens on a diet containing 50 g protein/kg plus urea (P< 0.05).

3. Nitrogen utilisation in conventional birds was significantly less when a diet of moderate protein content was fed than when a low protein diet plus urea was fed, but the opposite effect was seen with colostomised birds (P <0.05).

4. Colostomy increased urea excretion (nitrogen/kg body weight/day) from 4 to 9 mg in chickens fed on the moderate protein diet, but greatly, from 45 to 182 mg, in those fed on the low protein diet plus urea (P<0.05).

5. Blood urea concentration increased by about 20 mg per 100 ml in 3 h, a value which was maintained up to 6 h but which returned to the prefeeding concentration at 24 h; both control and colostomised chickens on the low protein diet plus urea responded similarly.

6. After feeding urea, half the daily excretion of urea was observed to occur within 6 and 9 h, respectively, in control and colostomised chickens. The excretion rate of urea (the peak occurred during 3.6 h in the colostomised and during 1.3 h in the control) was at least twice as high in colostomised as in normal birds 3 h postfeeding.

7. It is concluded that the caeca play a useful role in nitrogen economy of the protein‐depleted chicken, but not in the protein‐adequate chicken and that dietary urea degradation in the caeca occurs from 3 h after feeding.     

Relationship between physical property of soil and growth of Monochoria vaginalis under paddy condition of organic farming—analysis using settled soil volume in water of superficial layer.

Field experiments were conducted to analyze the relationship between the settled soil volume in water (SSVW) and the growth of Monochoria vaginalis (Burm. f.) Kunth under organic farming conditions. SSVW corresponds to the mud volume per dry matter weight. Soil was sampled from the superficial layer of the topsoil (<10 mm), which was of a finer texture than the rest of the topsoil. Without the application of rice bran, there was a negative correlation between SSVW and the number of individuals of M. vaginalis. This finding suggests that SSVW is useful as a physical indicator for the growth suppression of M. vaginalis. The application of rice bran dramatically reduced the number of M. vaginalis. The values of SSVW with rice bran were greater than those without rice bran. The analysis of SSVW indicates that the change in soil physical properties following the application of rice bran was one of the factors responsible for the suppression of M. vaginalis growth.     

Maintenance nitrogen requirements of adult female ostriches (Struthio camelus)

Successful ostrich farming requires knowledge of the nutritional needs of the birds. While much information is available on the nutritional value of various feed ingredients fed to ostriches, there is little known about their specific nutrient requirements. In this study, we measured the maintenance nitrogen requirements (MNR) of ostriches by nitrogen balance. We predict, based on the previous analysis of nitrogen requirements of various species of birds, that ostriches would have a MNR of 13.6-19.1 g N/day and a total endogenous nitrogen loss (TENL) of 2.8-5.1 g N/day. Three adult female ostriches were fed five pelleted diets containing 0.6-2.3% N [4-14.6% crude protein (CP)], 17.5 kJ/g gross energy (11.4 kJ/g ME) and 30% neutral detergent fibre. Each dietary trial consisted of a 10-day adaptation period, followed by a 5-day total excreta collection period. Body mass (109 ± 3 kg) and metabolizable energy intake (20.5 ± 0.7 MJ/day) were unaffected by dietary nitrogen levels. After correcting for excreta nitrogen losses during drying, MNR was calculated to be 481 mg N/kg(0.75) /day or 16.2 g N/day (100 g CP/day), and TENL as 310 mg N/kg(0.75) /day or 10.5 g N/day. Failure to correct for the 10.9 ± 4.1% average N losses during drying would underpredict the 'true' MNR by 35% and TENL by 46%. Our estimate for MNR of ostriches predicts a dietary requirement of 6.7% protein. Our estimate of TENL was nearly twice that predicted, possibly reflecting the high fibre content of their diet.     

Patterns of aquaporin expression in the canine eye

Aquaporins (AQPs) function as water channels in many types of cells involved in fluid transport. More than 10 isoforms have been identified, and these are differentially expressed in many types of mammalian cells in the body. Six AQPs (AQP0, AQP1, AQP3, AQP4, AQP5, and AQP9) have been identified in the eyes of humans and/or rodents. The unique permeability characteristics and distribution of AQPs indicate their diverse roles in the regulation of water homeostasis in the eye. The aim of this study was to investigate the localisation of AQPs in normal canine eyes, with AQP0 protein expressed in the crystalline lens and retina. Although AQP1 mRNA was detected in various areas of the canine eye, its protein expression was limited to the cornea, iris and ciliary body. AQP4 was identified in the iris, retina and optic nerve. AQP3 and AQP5 were found in the cornea and conjunctiva, and their expression was particularly high in the limbus. AQP3 and AQP5 were present in the nictitating membrane indicating that they play a role in water transport within the membrane. The observations suggested that several subtypes of the AQP family are involved in the regulation of water homeostasis in the canine eye.     

Relationship of decreased caecal urease activity by dietary penicillin to nitrogen utilisation in chickens fed on a low protein diet plus urea

1. The relationship of the decreased caecal urease activity by dietary penicillin to nitrogen utilisation was assessed in chickens fed a low protein diet plus urea.

2. Dietary penicillin at 20 and 100 mg/kg decreased anaerobic bacteria counts, urease activity and ammonia concentration in caecal contents (P< 0.05, except for ammonia in the case of the 100 mg/kg penicillin diet).

3. The 20 mg/kg penicillin diets significantly increased the excretion of urea and total nitrogen (P < 0.05) and decreased ammonia excretion, and significantly reduced nitrogen retention (P < 0.05). The 100 mg/kg penicillin diet also resulted in similar but not significant changes, which tended to be less than those by the 20 mg/kg penicillin diet.

4. Ammonia, urea, glutamine and uric acid concentrations in blood, liver and kidney were unchanged by dietary penicillin.

5. It is concluded that caecal ammonia production from urea was closely correlated with nitrogen utilisation in chickens fed a low protein diet plus urea.     

Diagnostic significance of serum glycated albumin in diabetic dogs

Measurements of serum fructosamine, glycated hemoglobin, and glycated albumin (GA) are increasingly used to complement serum glucose concentration for better management of diabetes mellitus. Fructosamine tests are currently not performed in veterinary medicine in Japan. As such, the measurement of GA may serve as a replacement test. Therefore, in the current study, serum GA and fructosamine were evaluated for a positive correlation in dogs, and, depending on the correlation, a reference range of GA percentage would also be determined from healthy control dogs. The degree of glycemic control in diabetic dogs was determined by fructosamine concentration. A positive correlation between GA and fructosamine was observed with both normal and diabetic animals. In addition, the reference interval of serum GA percentage in control dogs was determined to be 11.4-11.9% (95% confidence interval). Interestingly, no significant difference in serum GA percentages was observed between samples from diabetic dogs with excellent glycemic control and control dogs. However, good, fair, and poor glycemic control diabetic dogs resulted in a significant increase in serum GA percentages in comparison with control dogs. These results suggest that serum GA may be a useful diagnostic indicator, substituting for fructosamine, to monitor glycemic control in diabetic dogs.     

Studies of the constituents of Uruguayan propolis

Eighteen flavonoids including two new compounds, four aromatic carboxylic acids, and eleven phenolic acid esters including one new compound were isolated and identified from the ethyl acetate soluble fraction of the 70% ethanol extract of Uruguayan propolis. The new compounds were elucidated as pinobanksin 3-(2-methyl)butyrate (1; recently reported in Usia, T.; Banskota, A. H.; Tezuka, Y.; Midorikawa, K.; Matsushige, K.; Kadota, S. J. Nat. Prod. 2002, 65, 673-676) pinobanksin 3-isobutyrate (2), and 2-methyl-2-butenyl ferulate (24). The constituents isolated from Uruguayan propolis in this study were similar to those of propolis of European and Chinese origin. Thus, it is suggested that the Uruguayan propolis has a plant origin similar to those of propolis from Europe and China.