Blood vitamin levels in dogs with chronic kidney disease.

Chronic kidney disease (CKD) may affect excretion and metabolism of vitamins but data for dogs are limited. In this study, blood vitamin levels were investigated in 19 dogs with chronic renal failure. High performance liquid chromatography was used to quantify retinol, retinyl esters, tocopherol, thiamine, riboflavin, pyridoxal-5'-phosphate, ascorbic acid and 25-hydroxycholecalciferol concentrations, whereas cobalamin, folate, biotin and pantothenic acid were measured by microbiological methods. Levels of retinol, retinyl palmitate, ascorbic acid, and vitamins B1, B2 and B6 were increased compared to healthy dogs. Dogs with CKD showed decreased concentrations of 25-hydroxycholecalciferol and folate. Alpha-tocopherol, biotin, pantothenate and cobalamin levels were not significantly different between controls and dogs with CKD. Whether lower vitamin D and folate concentrations in dogs with CKD justify supplementation has to be evaluated in future studies.

The effect of vitamin C supplementation in healthy dogs on antioxidative capacity and immune parameters.

The aim of the study was to investigate the ability of vitamin C to increase the antioxidative and immunomodulating potential in healthy dogs. Fifteen dogs were tested for the effects of orally administered vitamin E (60 mg dl-alpha tocopheryl acetate) in combination with vitamin C (0, 30 or 60 mg ascorbic acid crystalline). Three treatments (0, 30, 60 mg vitamin C) were tested in a 3 x 3 cross-over study in three periods of 36 days. Pre-prandial blood samples were taken for analysis of vitamins C, E, A, retinyl palmitate and stearate, antioxidant status [Thiobarbituric acid reactive substances (TBARS) and uric acid], biochemical and haematological analysis. Subpopulations of lymphocytes, mitogen-induced peripheral blood mononuclear cell proliferation (PBMC) and serum IgA and IgG concentrations were determined. There was a trend (p = 0.056) for an increased plasma vitamin C concentration by vitamin C supplementation. There was no evidence that dietary treatment altered neither the other plasma vitamin concentrations nor TBARS and uric acid concentrations nor the subpopulations of the lymphocytes except for the number of CD4+ lymphocytes that increased with vitamin C supplementation. There was no effect of vitamin C on serum IgA and IgG concentration. A significant time x treatment interaction was demonstrated on PBMC's to pokeweed, with an increase observed by 30 mg vitamin C supplementation but a decrease by 60 mg vitamin C supplementation. There was no clear evidence for an effect of dietary vitamin C on antioxidative capacity in healthy dogs fed a diet with vitamin E concentrations well above the recommendations. Yet, a limited number of immunological parameters were slightly affected.

Histological and immunohistochemical evaluation of duodenal and colonic biopsies after oral bovine lactoferrin supplementation in beagle puppies.

Lactoferrin is a natural compound in the milk of mammals and was shown to influence the intestinal micro-flora and the immune system in mice, calves, dogs and man. The present study was carried out to investigate the effect of orally administered bovine lactoferrin (0, 30, 60 and 120 mg/kg DM feed) on the intestinal morphology and lymphocyte colonization in 36 motherless raised puppies. Endoscopic biopsies from duodenum and colon, taken in week 14, were scored histologically after staining with haematoxylin and eosin (H&E) and lymphocytes (CD3+, CD4+, CD8+) and plasma cells (IgA+, IgG+, IgM+) were enumerated after immunohistochemical staining by computer-aided quantification. Histological scoring revealed no significant differences amongst the groups. IgG+ plasma cells were reduced (p < 0.05) in the lamina propria of the colon of the 30 and the 60 mg group. The number of CD8+ lymphocytes was higher (p < 0.05) in the epithelium of the colon of the lactoferrin groups. In conclusion, this study indicated only minimal effects of bovine lactoferrin on the population of selected immune cells in the gut mucosa of puppies. More investigations are needed to describe the impact of lactoferrin on the digestive physiology of puppies.