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.