BACKGROUND: Vitamin A is a lipid soluble vitamin which can be stored in the body organs (especially in liver) and its supply is only through ration. Objectives: The present study has been conducted to evaluate vitamin A status of feedlot cattle in the city of Garmsar and impact of season and nutritional management on it. Methods: During the study 100 blood samples were taken from feedlot cattle of 6 farms in cold seasons of one year and 100 samples from 5 farms in warm seasons of the same year. Also, 50 blood and liver samples of slaughtered feedlot cattle were taken from Garmsar slaughter house in each of the mentioned seasons. Serum and hepatic tissue concentrations of vitamin A and beta carotene were measured by using standard biochemical methods. Student’s t-test and Tukey’s HSD tests were used for analysis  of the results and  pResults: The results of present study showed that mean serum and hepatic concentration of vitamin A in feedlot cattle in the city of Garmsar was in defined normal range for cattle and these animals did not show any vitamin A deficiency, but mean serum beta carotene concentration was at a very low level and lower than defined normal range for this species. Mean serum vitamin A concentration of feedlot cattle in cold seasons was significantly higher than that in warm seasons (p<0.05), conversely serum beta carotene concentration of feedlot cattle during warm seasons was significantly higher than that in cold seasons (p<0.05). However, comparing vitamin A concentration of liver tissues of feedlot cattle in cold and warm seasons did not show any significant difference (p>0.05).  ConclusionS: From the results of the present study it can be concluded that serum and hepatic concentration of vitamin A in feedlot cattle of the city of Garmsar was in normal reference range of cattle, and in spite of very low concentration of serum beta carotene concentration, due to supplementation of this vitamin in feed, vitamin A deficiency did not occur in these cattle.

Dairy cows may infrequently give milk tinged with blood after calving, which is a condition termed haemolactia. Economic losses for dairy farmers are caused by cases of haemolactia because of the condemnation of such milk, potential contamination of good bulk tank milk with haemolactic milk, and need for veterinarian intervention. This study was performed to elucidate the oxidative status of dairy cows with haemolactia during the peripartum period. Plasma glutathione peroxidase, malondialdehyde (MDA) and superoxide dismutase concentrations along with serum vitamin A, C and E concentrations were determined as indices of oxidative stress. The sampled dairy cows comprised two haemolactic (n = 11 and n = 6) and two non-haemolactic (n = 11 and n = 6) groups. On the first day when haemolactia was identified in colostrum (at mean 2.1 days after parturition), a significantly increased concentration of plasma MDA was noted in the haemolactic group. During the prepartum period, low levels of serum vitamin E were continuously observed from prepartum week 4 to the parturition day but only in the haemolactic group. These results demonstrate that continuous low levels of serum vitamin E in the prepartum period may play a pivotal role as a requisite factor in the onset of haemolactia after calving.

Heinz body formation was examined in kittens, in response to consumption of a variety of diets. A commercial salmon-based diet containing 16.5 mg of nitrite, 39 mg of histamine, and 210,000 IU of vitamin A/kg of diet (dry-matter basis) was found to induce Heinz body formation. Purified experimental diets--containing nitrite up to 405 mg/kg; histamine, 50 mg/kg; histamine, 50 mg/kg plus nitrite, 45 mg/kg; or vitamin A, 250,000 IU/kg--failed to induce Heinz body formation. The effect of propylene glycol (PG) on Heinz body formation was examined by giving groups of 6 kittens purified diets containing 5 or 10% PG for 12 weeks. Two additional kittens were fed a commercial soft-moist diet containing PG for 12 weeks. All kittens fed PG developed Heinz bodies, with peak values for erythrocytes containing Heinz bodies being: 28% for kittens of the 10% PG group; 20% for kittens of the 5% PG group; and 36% for kittens of the soft-moist diet group. Kittens did not develop anemia or methemoglobinemia. Heinz body percentage required 6 to 8 weeks to decrease to the pretreatment value of < 1% after diets containing PG were discontinued. 51Chromium-labeled erythrocytes were used to evaluate erythrocyte survival in 4 kittens of the 10% PG-fed group and in 4 control kittens. Kittens with Heinz body formation induced by 10% PG had significantly (P < 0.001) decreased erythrocyte survival, compared with that for controls, with half-life of 8.3 days for kittens of the PG group, compared with 12.6 days for kittens of the control group.

Objective: To investigate the influence of oxidative stress in terms of antioxidant capacity and lipid peroxidation on the probability of motor neuron disease (MND) in horses. Animals: 88 horses with MND (cases) and 49 controls. Procedures: Blood samples were collected from all horses enrolled, and RBCs and plasma were harvested. Activity of the enzyme erythrocytic superoxide dismutase 1 (SOD1) was determined in the RBCs. Plasma concentrations of α-tocopherols and β-carotenes and activity of glutathione peroxidase were also evaluated. Degree of lipid peroxidation was measured by determining plasma concentrations of lipid hydroperoxides. Differences were evaluated between horse groups. Results: Cases had lower erythrocyte SOD1 activity than did controls, but the difference was not significant. On the other hand, plasma vitamin E concentrations differed significantly between groups, with the cases having lower concentrations. Neither plasma vitamin A concentration nor glutathione peroxidase activity differed between groups; however, cases had significantly higher concentrations of lipid hydroperoxides (18.53μM) than did controls (12.35μM). Conclusions and Clinical Relevance: Horses with MND differed from those without MND by having a lower plasma concentration of vitamin E and higher concentrations of lipid hydroperoxides. Results parallel the findings in humans with sporadic amyotrophic sclerosis and provide evidence supporting the involvement of oxidative stress in the 2 conditions.

Epidemiologic relations were evaluated between plasma concentrations of nutrients and cardiovascular diseases. A total of 220 cats were assessed: 144 cats with noninduced acquired heart disease and 76 clinically normal cats. Plasma was assayed for taurine, alpha-tocopherol, selenium, retinol, and total cholesterol and triglycerides concentrations. Cardiovascular disease groups included dilated cardiomyopathy (n = 53), left ventricular hypertrophy (n = 28), hyperthyroidism (n = 11), and uncertain classification (n = 52). In cats with dilated cardiomyopathy, mean plasma taurine concentration was the lowest of that in cats of any group, being only 38% of the value in healthy cats; females had less than half the mean value of males. Tocopherol concentration was 20% lower than normal, and retinol concentration was 40% higher than normal. Total cholesterol concentration was 36% lower than normal. Triglycerides concentration was higher in these cats than in any other group-twice the value recorded in healthy cats and 67% higher than that in hyperthyroid cats. In cats with hypertrophic cardiomyopathy, almost 15% had mean plasma taurine concentration < 30 micromol/L. Retinol concentration was 15% higher, and triglycerides concentration was 54% higher than normal. Approximately 27% of hyperthyroid cats had mildly decreased plasma taurine concentration. Hyperthyroid cats had the lowest tocopherol and cholesterol values; both were at least 30% lower than normal. Retinol concentration was 30% higher than Approximately 14% of cats with uncertain classification had mildly decreased plasma taurine concentration. Plasma retinol and triglycerides concentrations were higher than normal in 25 and 38% of these cats, respectively. Plasma selenium concentration, compared between healthy cats and cats with cardiac disease, was not significantly different. This observation may not be meaningful, however, in light of the limited number of cats in which selenium was assessed. Although significant correlation was not observed between plasma taurine and plasma retinol, tocopherol, or cholesterol concentrations in cats with cardiac disease, plasma tocopherol and cholesterol values were highly associated (P < 0.01). Also, the molar ratio of cholesterol to tocopherol was significantly (P < 0.05) lower in cats with dilated cardiomyopathy, compared with healthy cats.

Serum retinol, retinyl palmitate, and total vitamin A concentrations, and jejunoileal morphology were examined in neonatal calves infected with Cryptosporidium parvum. Group-1 calves served as noninfected controls and, after an adjustment period, were given 50 ml of saline solution IV every 12 hours for 6 days. Group-2 calves were inoculated with 10(7) C parvum oocysts and, after the onset of diarrhea, were given 50 ml of saline solution IV every 12 hours for 6 days. Group-3 calves were inoculated with 10(7) C parvum oocysts and, after the onset of diarrhea, were treated with difluoromethylornithine (DFMO, 200 mg/kg of body weight IV, q 12 h) for 6 days. Group-4 calves were naturally infected with C parvum. Jejunoileal biopsy specimens were excised from calves of groups 1-3 at 3 and again at 15 to 16 days of age. During the course of diarrhea and 3 days after saline or DFMO administration, water-miscible retinyl palmitate was administered orally (2,750 micrograms/kg) to each calf in each group. Cryptosporidium parvum infection was associated with significant (P < 0.05) reduction in postadministration serum retinol, retinyl palmitate, and total vitamin A concentrations in calves of groups 2, 3, and 4. Cryptosporidium parvum infection caused significant (P < 0.05) reduction in villus height. Decreased villus height, villus blunting and fusion, and attenuation of the intestinal mucosa were associated with reduced absorption of vitamin A, as indicated by lower peak postadministration retinyl palmitate concentration in C parvum-infected calves. Intravenous administration of DFMO to group-3 calves did not improve retinol absorption. Vitamin A should be provided parenterally to young calves with enteric cryptosporidiosis in an attempt to avoid depletion of concurrent low liver vitamin A reserves.

Full-thickness skin wounds were created on the dorsum of both metacarpi in 8 horses. Three topical treatment regimens were studied. All wounds were bandaged with a nonadherent dressing, which was held in place with a snug elastic wrap. Group-A wounds were treated with a proprietary topical wound medication that consisted of a spray and an ointment. Group-B wounds were treated with the same regimen, except the putative active ingredients in the ointment were omitted. Group-C wounds were treated with a dry nonadherent bandage only. Wound dressings were changed every day and the limbs were photographed every other day until the wounds were healed. Specimens of normal skin and biopsy specimens of healed wounds were examined histologically and were assayed for hydroxyproline content. Wound healing measurements quantitated for each wound were number of days to healing, maximal wound size attained, day wound contraction commenced, day epithelium first noticed, rate of wound contraction, final wound size, and fraction of the wound that healed by contraction. The cosmetic appearance of the healed wounds was also graded. Significant differences were not noticed in hydroxyproline content, histologic appearance, or any of the wound healing measurements between treatment groups. The cosmetic appearance of healed group-A and -B wounds was significantly better than the appearance of group-C wounds. The topical treatment regimens studied neither enhanced nor inhibited wound healing in this study.

Effects of dietary aflatoxin (AF) and supplemental vitamin E (d-alpha-tocopherol) were evaluated in growing crossbred pigs. Nine barrows (3 replicates of 3 each, mean body weight, 14.0 kg) per group were assigned to 1 of 4 treatment groups (for a total of 36 barrows): 0 IU of supplemental vitamin E and 0 mg of AF/kg of feed (control); 2,400 IU of vitamin E divided into equal doses and administered IM on days 1 and 16; 2.5 mg of AF/kg of feed; or 2.5 mg of AF/kg of feed plus 2,400 IU of vitamin E administered similarly to treatment 2. Barrows were administered their respective treatment for 32 days. Evaluations were made for group production performance and for serum biochemical, immunologic, hematologic, pathologic, serum and tissue tocopherol, and serum retinol variables. Body weight was reduced by AF-alone and AF plus vitamin E treatments, compared with control and vitamin E-alone treatments. Liver weight was increased for the AF alone-treated and the AF plus vitamin E-treated barrows, compared with control barrows. The AF alone-treated barrows had alterations in: serum values of alkaline phosphatase, gamma-glutamyltransferase, albumin, glucose, phosphorus, calcium, cholesterol, total iron, unsaturated iron-binding capacity, total iron-binding capacity, and urea nitrogen; RBC numbers, hematocrit, hemoglobin concentration, and prothrombin time; and mitogen-induced lymphoblastogenic responses. With the exception of some slight ameliorating effects on hematologic measurements, supplemental treatment with vitamin E did not prove beneficial against the toxicosis-associated AF treatment. The AF alone-treated barrows had decreased serum tocopherol and retinol concentrations, compared with control and pretest values, and decreased tocopherol concentration in cardiac tissue. High parenterally administered doses of vitamin E did not have sparing effect on Af-induced reductions of serum tocopherol or retinol concentration; however, compared with pretest values, serum tocopherol concentration was increased by vitamin E-alone treatment. Tocopherol concentration in cardiac tissue of the AF plus vitamin E-treated barrows was increased over that of the AF alone-treated barrows, indicating an ameliorating effect on AF-induced tissue concentrations reductions. These data indicate that vitamin E may not have a sparing effect on AF-induced toxicosis and that AF may reduce serum retinol and serum and tissue tocopherol concentrations.

We used size-exclusion high-performance liquid chromatography (HPLC) to investigate the properties of the 2 isoforms of vitamin A-containing (holo) retinol-binding protein (RBP) in animals: the form that is bound to transthyretin (holo-TTR-RBP), and the form that does not bind to TTR (holo-free RBP). We also used radial immunodiffusion to measure immunologically active RBP (apo+ holo RBP). We compared the isoforms of RBP in animals with those of human beings to determine which animal is the best model of human RBP. Size-exclusion HPLC detected holo-free and holo-TTR-RBP in every animal species studied. Apparent concentration of holo-TTR-RBP varied among species: that of rabbits and dogs much greater than that of apes, sheep, goats, monkeys, rhinoceroses, felids, rats, human beings, and deer greater than that of pigs, zebra, and bison greater than that of penguins. Dogs have unusual RBP chromatograms; they have high concentration of RBP, but also appear to transport much of their vitamin A on proteins other than RBP, Human RBP antibody preparations could detect apo + holo RBP immunologic activity only in apes, monkeys, and felids. Apes and monkeys appeared to have complete cross-reactivity to human RBP antibodies. Felids may have substantial, but partial, cross-reactivity. Apes and monkeys appear to be the most relevant animal models for study of human RBP transport. However, there is a need for less-expensive models. Further research is needed, but in the interim, rats or sheep may be satisfactory for some purposes.