The effect of dietary supplementation of cholesterol and its subsequent withdrawal on the liver lipids and serum lipoproteins of chickens

Abstract

Two groups of male chickens were fed either a control diet (group N) containing a standard poultry ration admixed with 10% corn oil or a cholesterol diet (group C) in which the control diet was supplemented with 1% cholesterol. After 6 weeks on the diets, a negligible amount of very low density lipoprotein (VLDL) was found in the serum from control animals. On the other hand, the serum VLDL from the cholesterol‐fed birds was the predominant lipoprotein and carried 72% of the total serum lipids. Surprisingly this lipoprotein from cholesterol‐fed animals was very low in triglycrides (6%) and high in total cholesterol (77%). While the level of serum low density liporotein was unaffected by the ingestion of cholesterol, the concentration of total lipids and phospholipids in the high density lipoprotein decreased in cholesterol‐fed animals. The greatest change in liver lipids from animals fed cholesterol was found in the cholesterol esters, whereas the unesterified cholesterol, triglyceride and phospholipid varied slightly or remained constant. In normal animals the distribution of cholesterol between the liver and the serum was about equal, whereas in the cholesterol‐fed birds the liver accounted for 80% of the cholesterol found in the liver‐serum pool. In order to determine how the hypercholesterolemic bird responds to the withdrawal of cholesterol from the ration, a diet‐exchange experiment was conducted. In this study the birds that were originally fed the cholesterol diets (group C) for 6 weeks were placed on the control diet (group CN) and the birds fed the control diet (group N) for 6 weeks were given the cholesterol diet (group NC). At periodic intervals, 1, 3, 7 and 14 days following the change of diets, 3–5 animals from each group were sacrificed, and analyses performed on their serum lipoproteins and liver lipids. Within one day after the diet substitution, there was a 31‐fold increase and a 46% decrease, respectively, in the serum VLDL concentration in groups NC and CN as compared with their corresponding steady state values (groups N and group C, respectively). The liver cholesterol increased 4‐fold and decreased 40%, respectively, in the two groups NC and CN as compared with the values obtained before the diet substitution. It is suggested that the concentration of cholesterol in the liver is the principal factor controlling cholesterol metabolism in chickens fed a hypercholesterolemic diet.

Effect of Cholesterol Feeding on Serum Lipoproteins and Atherosclerosis in Atherosclerosis-Susceptible and Atherosclerosis-Resistant Japanese Quail

“…The RES Japanese quail behave in a manner similar to other atherosclerosis-resistant species, such as rats, dogs, and guinea pigs, which exhibit only a slight to moderate increase in their serum cholesterol upon ingestion of cholesterol-containing diets (Clarkson, 1971;Narayan, 1971;Puppione et al, 1971). Conversely, SUS quail responded in a manner similar to rabbits and chickens, which are sensitive to dietary cholesterol (Clarkson, 1971;Shore and Shore, 1976;Jones and Dobrilovic, 1969;Kruski and Narayan, 1972;Narayan and Calhoun, 1975). Thus, the high concentration of cholesterol circulating in the blood may possibly explain a higher incidence of atherosclerosis after cholesterol feeding for SUS quail as compared to RES quail.…”

“…Among the plasma (or serum) lipoproteins induced by cholesterol feeding, the VLDL cholesterol was markedly increased in pigeons, quail (Day et al, 1974), chickens (Jones and Dobrilovic, 1969;Kruski and Narayan, 1972;Narayan and Calhoun, 1975), rabbits (Shore et al, 1974;Shore and Shore, 1976;Day et al, 1974), rats (Day et al, 1974;Narayan and Calhoun, 1975;Lasser et al, 1973;Mahley and Holcombe, 1977), and hyperresponder dogs (Mahley et al, 1974). The absolute concentration of cholesterol of IDL and LDL were increased also in those animals except for pigeons and quail in which determinations were not made.…”

“…Cholesterol feeding increased the absolute concentration of HDL cholesterol in chickens (Kruski and Narayan, 1972;Narayan and Calhoun, 1975) and swine (Mahley et al, 1975) but decreased the absolute concentration in rabbits (Shore and Shore, 1976), rats (Lasser et al, 1973;Mahley and Holcombe, 1977), dogs (Mahley et al, 1974), and monkeys (Mahley et al, 1976;Rudel et al, 1979). In another report, HDL cholesterol did not change in chickens (Jones and Dobrilovic, 1969).…”

The correlation between serum total cholesterol and some trace elements in serum, liver and heart of rats fed high cholesterol diet

“…Variations in serum lipids from adding fat and cholesterol to the diet have been reported by Hutagalung [9] and Kruski et al [15]. In a rabbit atherosclerosis model, atomic absorption spectra analysis of trace elements indicated positive correlation between atherosclerosis and the concentration of zinc and copper in the posterior wall of the left ventricle [3].…”

Pharmacological Studies on Experimental Nephritic Rats (4) Improvement of Hyperlipemic Models in Rats Utilizing Anti-Rat Kidney Rabbit Serum and Effects of Anti-Hyperlipemic Agents on Serum Lipid Levels.

“…As an experimental hyperlipemic model used to screen anti-hyperlipemic agents, a high lipid diet containing cholesterol has been fed to various species (1)(2)(3)(4)(5). It is known that rats (2) exhibit only a slight increase in serum lipid levels as compared with the very high increase in serum lipids observed in rabbits (1).…”