Effect of fiber on cholesterol metabolism in the Coturnix quail

Plasma and yolk cholesterol levels in Japanese quail divergently selected for plasma cholesterol response to adrenocorticotropin

Studies were conducted to determine the effect of divergent selection for plasma cholesterol response to adrenocorticotropin (ACTH) on the levels and relationships between plasma and yolk cholesterol in Japanese quail. Cholesterol data were obtained in Generation 25, following seven generations of relaxed selection, from birds maintained under a normal environment with no exposure to exogenous ACTH. Levels of plasma and yolk cholesterol were determined at 22 and 28 wk. Plasma cholesterol levels of quail in the low cholesterol line were significantly (P less than .01) lower than levels in the high line at both ages (224 versus 383 and 209 versus 326 mg/100 mL, respectively). In contrast, yolk cholesterol levels were significantly (P less than .01) higher in the low line than in the high line (24.1 versus 21.5 and 21.1 versus 16.9 mg cholesterol/g yolk at 22 and 28 wk, respectively). A significant line by sex interaction was present at both ages for plasma cholesterol with females having higher cholesterol values than males in the low line and males having higher values than females in the high line. A negative relationship was observed between changes in plasma and yolk cholesterol in the selected lines. Greater deposition of cholesterol in the yolk of the line with lower plasma cholesterol indicates that excretion rate may play a role in explaining genetic differences in plasma cholesterol.

Cholesterol metabolism in the laying hen as influenced by dietary cholesterol, caloric intake, and genotype

Three trials, each with 24 hens, were conducted to determine the effects of dietary cholesterol, caloric intake, and genotype on the synthesis, storage, and excretion of cholesterol in the laying hen. The two genotypes of birds used in this experiment had been divergently selected for high and low oxygen consumption and had been shown to differ significantly (P less than .01) in body weight gain and carcass lipid deposition from 0 to 4 weeks of age. The dietary treatment, administered for a 2-week period to birds in each genotype, consisted of two levels of dietary cholesterol (0 and 1% added) and two energy intakes (ad libitum and 75% ad libitum). The experimental design was a 2 X 2 X 2 factorial. One percent added cholesterol versus none supplemented produced a significant (P less than .01) decrease in available metabolizable energy and uptake of acetate into liver cholesterol while causing significant (P less than .01) increases in egg and liver cholesterol but not in plasma cholesterol. Restricting caloric intake, as compared to ad libitum feeding, resulted in significantly (P less than .01) decreased egg production and total amount of cholesterol excreted via the egg with significantly (P less than .05) increased plasma and liver cholesterol levels but no change in egg cholesterol concentration. Differences were significant (P less than .05) between the two genotypes in feed intake and hepatic cholesterol and lipid synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of increasing the fibre content of a layer diet

The fibre content of a basal diet fed to laying hens was increased from 149.2 g to between 218.6 and 292.3 g/kg by the inclusion of various fibrous farm wastes and by-products at 200 g/kg diet. The fibrous ingredients lowered the metabolisable energy (ME) of the basal diet from 11.82 to between 9.31 and 11.21 MJ/kg. Utilisation (g food/kg egg) of the basal diet was not significantly different from values for diets containing maize cob, cassava or maize starch residues. The diet containing maize cob supported a performance similar to that of the basal diet, despite a lower energy content (10.08 MJ/kg). Diets containing cowpea shell, cassava peel or sawdust, with lower energy contents, and those containing maize starch residue, palm kernel meal or dried brewers grains, with higher energy contents, were not as good. The diet containing cassava starch residue supported similar egg production to the basal but egg size was less. Inclusion of some of the fibre sources caused slight decreases in yolk cholesterol, although this could not be correlated with dietary fibre content. Additional dietary fibre caused slight increases in gizzard weight but this was also not simply related to dietary fibre content.