An experiment was conducted to study the effect of large-dose (-carotene supplementation on blood retinoid and (-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 102and 103mg/kg (-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 (-carotene concentrations. Granulosa cells were isolated from ovarian follicles (F1and F2), and PMSG-inducedin vitroprogesterone (P4) secretion was measured. Similar retinol concentrations were found in both (-carotene supplemented groups, indicating saturation of the retinol-transporting system. (-carotene supplementation was accompanied by hypercarotenaemia, but did not increase the retinyl palmitate levels in the blood. PMSG-induced P4production of the granulosa cells decreased significantly in Groups BC1 and BC2 in a dose-dependent manner.
Authors:J. Janan, L. Bárdos, Mária Karsai, Gabriella Ágota, Péter Rudas, J. Kozák and L. Bódi
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 feedingad 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), (-carotene (BC, 3504 ± 3107 µg/l), retinol (ROL, 1160 ± 505 µg/l), retinyl palmitate (RP, 1745 ± 405 µg/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 µg/l, ROL = 687 ± 375 µg/l, RP = 1398 ± 607 µg/l, and TCh = 2.83 ± 1.98 mmol/l). All differences were significant except those found for albumin and (-carotene. No significant sex- or genotype-related effects were observed for these parameters.