Relationship of retinoid and carotenoid metabolism with caecotrophy in rabbits.

The relationship of retinoid and carotenoid metabolism with caecotrophy was studied in adult female New Zealand White rabbits kept in individual metabolic cages. Caecotrophy was prevented by the use of plastic collars. The dry matter, crude protein, fibre, fat and ash contents of hard and soft faecal samples were determined. The retinoid (retinol and retinyl palmitate) and carotenoid (canthaxanthin, beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin) levels of the blood, liver, kidney, caecal content and faeces were also measured by high-performance liquid chromatography (HPLC). The prevention of caecotrophy resulted in a significant decrease of blood retinol (P < 0.001) and retinyl palmitate (P < 0.01) concentration but it did not cause any significant change in the retinol and retinyl palmitate contents of the liver and kidney. The caecal content (25.78 +/- 6.87 microg/g) and the soft faeces (34.52 +/- 10.48 microg/g) contained the retinoids in similar amounts. Various carotenoids were found in considerable amounts in different types of faeces, while in the tissues (blood, liver and kidney) these pigments did not occur in substantial amounts. Total carotenoid concentration was similar in the caecal content (11.23 microg/g) and in the caecotroph (13.85 microg/g). On the basis of the results it can be assumed that the retinoid content of rabbit feed could be lowered in the presence of adequate caecal function and caecotrophy.

Effect of large dietary doses of beta-carotene on plasma retinoid and beta-carotene levels and on progesterone production in the granulosa cells of Japanese quail.

An experiment was conducted to study the effect of large-dose beta-carotene supplementation on blood retinoid and beta-carotene levels as well as on the progesterone secretion of the granulosa cells in Japanese quail. Laying quails were assigned to three dietary groups. The control group (Group C) received the basal diet (laying feed containing 9000 IU vitamin A/kg). In the treated groups (Groups BC1 and BC2) the basal diet was supplemented with 10(2) and 10(3) mg/kg beta-carotene (BC), respectively. At the end of the two-week feeding period, 10 birds from each group were euthanised. Blood samples were analysed for retinol, retinyl palmitate and beta-carotene concentrations. Granulosa cells were isolated from ovarian follicles (F1 and F2), and PMSG-induced in vitro progesterone (P4) secretion was measured. Similar retinol concentrations were found in both beta-carotene supplemented groups, indicating saturation of the retinol-transporting system. beta-carotene supplementation was accompanied by hypercarotenaemia, but did not increase the retinyl palmitate levels in the blood. PMSG-induced P4 production of the granulosa cells decreased significantly in Groups BC1 and BC2 in a dose-dependent manner.

Relationships between force-feeding and some physiological parameters in geese bred for fatty liver.

The susceptibility of geese of different genotypes and sexes to force-feeding, some plasma biochemical parameters (thyroid hormones, cholesterol, retinoids, total protein and albumin) of force-fed geese, and the relationship between force-feeding, fat storage and the above-mentioned parameters were studied. Sixty (30 male and 30 female) geese of three genotypes (Hungarian, Landes and their crossbred called Babat Hybrid) were divided in two groups at 12 weeks of age. Geese in one group (5 males and 5 females from each genotype) received mixed feeding ad libitum. Birds in the other group were force-fed with maize. After 3 weeks all birds were bled, blood samples were taken, and the above-mentioned plasma parameters were determined. Thyroxine (T4) levels were significantly lower in force-fed (11.6 +/- 3.5 ng/ml) than in control geese (22.7 +/- 4.09 ng/ml). Plasma triiodothyronine (T3) level was also lower in the force-fed than in the control group, but the difference was not significant (1.87 +/- 0.23 ng/ml and 2.11 +/- 0.28 ng/ml, respectively). Plasma total protein (TP, 45.2 +/- 4.5 g/l), albumin (ALB, 16.51 +/- 2.8 g/l), beta-carotene (BC, 3504 +/- 3107 micrograms/l), retinol (ROL, 1160 +/- 505 micrograms/l), retinyl palmitate (RP, 1745 +/- 405 micrograms/l) and total cholesterol (TCh, 4.32 +/- 0.55 mmol/l) levels were elevated in the force-fed group as compared to the control (TP = 36.4 +/- 5.1 g/l, ALB = 15.6 +/- 0.9 g/l, BC = 1657 +/- 1681 micrograms/l, ROL = 687 +/- 375 micrograms/l, RP = 1398 +/- 607 micrograms/l, and TCh = 2.83 +/- 1.98 mmol/l). All differences were significant except those found for albumin and beta-carotene. No significant sex- or genotype-related effects were observed for these parameters.

A new, modern, cost-saving micro/macro method for the determination of serum fructosamine.

Serum/plasma fructosamine (SeFa) concentration is a reliable indicator used in human diabetic control. Tests for monitoring the carbohydrate/energy metabolism of (farm) animals are less commonly performed in veterinary laboratories, since most of the reliable determinations, both automated and manual, are relatively expensive. The aim of this study was to develop a precise, money- (and time-) saving automated micro method for measuring SeFa. ELISA microplates (20 microL samples and 200 microL reagents) and an automatic microplate autoreader were used. The classical nitroblue tetrazolium (NBT) stain reagent solution of Johnson et al. (1982) was modified using a SIGMA reagent to render it stable for up to one year. SeFa concentrations measured by the new method in 30 human blood plasma samples were compared with values obtained by the standard (generally used) LaRoche kit procedure. Fifteen cow, 13 dog and 18 chicken plasma samples were assayed by the new automated 'micro' method as well as by the manual test tube 'macro' method commonly used earlier. The modified reagent was applied for both methods. The coefficient of correlation (r) between the results obtained by the two methods was consistently between 0.94 and 0.98 (p < 0.001).

Effect of beta-carotene and nucleotide base supplementation on blood composition and immune response in weaned pigs.

The effect of synthetic beta-carotene and synthetic nucleotide base on daily weight gain, feed consumption and certain haematological, biochemical and immunological parameters of piglets were studied in a 3-week experiment. Beginning one week prior to weaning, the diet fed to one experimental group of piglets was supplemented with 10% Rovimix Beta-carotene at 875 mg/kg of diet. Synthetic uracil and adenine (98%, Sigma-Aldrich) were mixed into the diet of the other experimental group at doses of 500 mg/kg of diet for each substance. The control group received the basic diet without any supplementation. The changes observed over time in the haematological parameters and in certain biochemical variables could be regarded as physiological. By day 21 of the experiment, beta-carotene supplementation had significantly lowered the neutrophilic granulocyte percentage and elevated the lymphocyte percentage, while in the other two groups a change of opposite tendency occurred. At the end of the experimental period there was a decrease in plasma vitamin E concentration due to carotene supplementation (control: 6.1 +/- 1.5, nucleotide: 6.3 +/- 2.5, carotene: 2.3 +/- 1.5 mg/L). Lymphocyte blastogenesis induced by phytohaemagglutinin and concanavalin A increased by 50 and 130%, respectively, in the nucleotide group and by 60 and 30%, respectively, in the carotene group, while it did not change in the control group. The supplements exerted no positive effect on the in vivo cellular immune response.

Storage of retinoids and beta-carotene in the genital organs of Japanese quail.

The present study was designed to investigate the effect of a one-month feeding of retinyl acetate (RA) on the retinol (ROL), retinyl palmitate (RP) and beta-carotene (BC) levels in the blood, testicles and ovarian follicles of adult Japanese quails. The basal diet (containing vitamin A at 10 x 10(3) IU/kg) was supplemented with 100 x, 500 x and 1000 x 10(3) IU/kg RA in Groups I, II and III in both sexes. Plasma vitamin A levels rose in all groups. The elevations were caused basically by the RP fraction. The ROL concentration increased only slightly, indicating saturation of the blood binding/transport system. Plasma BC was depressed in both sexes. RA feeding resulted in high RP concentration in the genital organs (testicles and ovarian follicles), indicating subclinical hypervitaminosis, while the BC content of genital organs decreased considerably. The retinoid and BC concentration of ovarian follicles (F1-F5) was in the same range, indicating continuous retinoid and carotene transport during the fast maturation period. Retinoid content of the genital organs was higher in layers than in roosters. BC deposition was decreased both in the testicles and in the follicles, indicating a competition between RP and BC for the storage capacity of organs.

Application of an anti-HQIgY antibody for the measurement of IgY concentrations of hen's and quail's serum and yolk.

The development of a sensitive ELISA for the measurement of quail IgY (QIgY) was the main purpose of our study. The suitable antibody (AB) was prepared in rabbits. Both quail IgY (QIgY) and hen IgY (HIgY) were precipitated by this developed AB. For this reason it was marked as anti-hen-quail-IgY (a-HQIgY). The purified AB was conjugated with horseradish peroxidase (aHQIgY-HRP) and a sensitive direct ELISA was developed, based on this labeled AB. The prepared aHQIgY AB which was used in this developed ELISA method was suitable for the measurement of total and specific IgY concentration in domestic hen (Gallus domesticus) and Japanese quail (Coturnix coturnix japonica) either. As a result of our experiments it is very likely that there are identical sequences of IgYs of both species. This part of IgY has good antigen character at the same time. Probably, this phenomenon has occurrence in other Galliform species, too. Further investigations will be carried out in this field.

Distribution of cadmium in selected organs of mice: effects of cadmium on organ contents of retinoids and beta-carotene.

Cadmium was administered to 32 adult ICR mice i.p. in two single doses (0.25 and 0.5 mg CdCl2, per kg of b.w.). After 48 hours concentrations of cadmium in kidneys, liver, spleen, muscle (m. quadriceps femoris), ovaries and testes and the concentration of retinyl palmitate, retinol and beta-carotene in kidney, liver and testes were determined. Significantly higher cadmium concentration was found in liver, kidney and ovary in both experimental groups in comparison with the control group (p<0.001). In muscle, spleen and testis the cadmium level was higher, however not significantly. No significant differences in the concentration of retinyl palmitate, retinol and alpha-carotene in liver were found. Concentration of alpha-carotene in kidney and testis was significantly decreased in both groups administered with cadmium (p<0.001). Concentration of retinyl palmitate was significantly lower in testis in the group with higher cadmium level (p<0.001) and the concentration of retinol significantly decreased in kidney and testis of mice after an administration of 0.5 mg CdCl2/kg b.w.

Effect of retinyl acetate, ascorbic acid and tocopherol supplementation of the feed on egg vitamin A content in Japanese quail.

The ration fed to laying Japanese quails was supplemented either with retinyl acetate (RA) (50 x 10(3) IU/kg, group A), ascorbic acid (500 mg/kg, group C), or with both substances in combination with each other (group AC) and with tocopheryl acetate (37.8 IU/kg; groups AE and ACE). On days 1, 8, 14, 20 and 28, some quantitative parameters of eggs (mass of egg-shell, albumen and egg yolk, retinoid content of egg yolk) were measured. The egg production parameters were not significantly affected by the supplementations. By the end of the second week, the total vitamin A (retinyl esters + retinol) concentrations of the egg yolk were significantly higher in the groups receiving supplemented feed (AC, AE and AEC) than in the control group. Two weeks later (on day 28), the vitamin A levels were elevated significantly in all groups except the group treated with ascorbic acid. From the point of view of vitamin A fortification of the egg yolk, the combined supplementations (groups AC, AE, AEC) seem to be more effective. The results indicate that vitamin A content of the egg yolk can be increased by a short-term RA supplementation of the laying ration. The retinoids present in the natural substances of eggs could possibly be a good source of vitamin A for humans.

Absorption of retinyl acetate in laying hens.

Absorption of retinyl acetate (RA) was studied in hens. Animals (n = 10-10) received 12.5-,25-,50-,100-,150-,200-,250- and 300 x 10(3) IU of RA in capsules (p.os). Before treatment (0) and 2nd, 4th, 6th and 8th hours later, as well as on the following day blood samples were taken for retinoid analysis. Vitamin A peaks were detected in the blood in the 4th hour. The alterations in the plasma vitamin A levels were caused basically by the elevations of the retinyl ester (RYL) fraction. The proportion of RYL was 7-27% of the total plasma vitamin A value in all groups at the time of RA administration (0 h). This RYL ratio was elevated parallel to RA doses, and in case of higher doses reached 80-90% (4th h). It has been found that the efficiency of RA absorption, in hens, is in inverse ratio to the dose that is used. The calculated relative absorption coefficients of efficiency have a close negative correlation (r = -0.89; p < 0.01) to the doses. Relationship between the maximum plasma retinoid concentrations and the dose/metabolic body mass can be fitted to the saturation function. It seems reasonable to conclude that in hens the absorption of retinol is an enzyme dependent and/or carrier mediated process even in cases of pharmacological doses.

Variations in the milk yield and milk composition of dairy cows during lactation.

Variations in the milk yield and milk composition of a dairy cow colony (n = 23) were analyzed during 11 months of lactation. Milk yield followed a characteristic decreasing pattern in negative correlations with solid components (milk protein, lactose, total solids, milk fat). Titrable acidity (degree SH) was significantly (p < 0.1) higher in the milk of fresh-milking cows and it correlated negatively with lactose and positively with milk protein, milk fat and total solids. The concentrations of Zn, Fe and Cu tended to decrease, while Mn showed insignificant variation during lactation. Milk vitamin A showed a significant positive whilst milk vitamin E had a negative correlation with milk fat.

Blood pH, plasma carotene, vitamin A, albumin and globulin concentrations in newborn calves and in dams during the first three days of the postnatal period.

Blood pH, total plasma carotene, plasma vitamin A fractions and some plasma proteins were determined in newborn calves (n = 38) and their dams. Calves were assigned to one of two groups according to their blood pH immediately after birth: group 1 (normal) with pH above 7.2 (n = 27) and group 2 (slightly acidotic) with pH 7.0 to 7.2 (n = 11). The difference between the neonatal blood pH values of the two groups immediately post partum disappeared 24 h after birth. The blood pH of the dams was normal. The extremely low plasma carotene concentration (group 1: 32.7 micrograms/l; group 2:20.5 micrograms/l) and the low plasma globulin fractions (group 1:19.6 g/l; group 2:19.2 g/l) immediately after birth were elevated by the intake of colostrum. There was no significant change in plasma vitamin A fractions (retinol, retinyl ester) during the early postnatal period (3 days post partum) in newborn calves. The acid-base balance of newborn calves does not have any influence on the physiological alterations of plasma vitamin A, carotene and some plasma proteins during the first three days of life.

Plasma vitamin A composition and retinol-binding protein concentration during egg formation in laying hens.

Blood plasma vitamin A composition (retinol, retinyl ester) and retinol-binding protein (RBP) were determined in three phases (empty; soft- and hard egg) of the egg formation period in laying hens. The retinyl ester level remained in the range of 6 to 11% of the total plasma vitamin A concentration during egg formation. The retinol and RBP increased significantly during the time of soft period. The molar ratio between retinol and RBP ranged between 0.72-0.77. The increase of retinol and RBP may be caused by the sexual steroid effect for satisfying the retinoid needs of the ovarium and shell gland (avian uterus).

Determination of glycohaemoglobin levels in ketonuric and non-ketonuric cows.

Glycohaemoglobin (GHb) was estimated in haemolysate from dairy cows by colorimetric (thiobarbituric acid reaction) and ion-exchange (batch chromatographic) methods. The percentage of the non-enzymatic glycosylation of red blood cell haemoglobin depends on the blood sugar level. In consequence of the low blood sugar level of bovines, bovine GHb exhibits a lower value than that of the other mammals. GHb level was 2.18% (+/- 0.73) and 2.39% (+/- 1.03) in ketonuric and non-ketonuric cows. respectively. The authors suggest that the lower GHb level of cows with subclinical ketosis (ketonuria) is an indicator of the animals' energy-deficient status in the previous weeks.