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Biomedical subjects

P R Cheeke

Publications and source records attributed to P R Cheeke.

At least 73 records · Page 4Linked to original sources

Effect of alfalfa and dietary fiber on the growth performance of weanling rabbits.

The addition of 10%, 20%, 30%, and 40% sun-cured alfalfa meal to a high-energy, low-fiber, basal diet for weanling rabbits gave increased average daily gains as compared to gain on the basal diet. Deaths from enteritis complex occurred only at the 0% and 10% alfalfa levels. When 2.5%, 5%, 7.5%, and 10% alfalfa meal were used, the average daily gains were numerically higher for all alfalfa-fed groups than for the basal diet. Maximum gains were achieved at the 20% alfalfa level. Alfalfa extracted with 95% ethanol retained its growth-stimulating effect when added to the basal diet. Feed preference trials gave conflicting results. In one trial, the basal diet was preferred over all alfalfa diets in a two-choice feed preference test, while in a second trial, all alfalfa diets were preferred over the basal diet. It was concluded that the growth of weaning rabbits fed a high energy diet was improved by the addition of alfalfa meal.

Animal Feed↗

Effect of alfalfa saponins on intestinal cholesterol absorption in rats.

Five to 20 mg of saponins obtained from alfalfa tops or roots were introduced intragastrically in rats also receiving oral and intravenous ring-labeled cholesterol. The saponins were tested before and after partial acid hydrolysis. Absorption of cholesterol was determined by estimation of fecal sterols and by a dual isotope technique involving assay of plasma radioactivity. Alfalfa top saponins (nonhydrolyzed) reduced absorption of cholesterol. Acid hydrolysis of alfalfa top or root saponins enhanced their ability to inhibit cholesterol absorption.

Animals↗

Resistance of the rabbit to dietary pyrrolizidine (Senecio) alkaloid.

Rabbits were fed Senecio jacobaea for 263 days. Total intake of the plant averaged 112.5% of initial body weight. No gross lesions, or changes in serum protein and albumin occurred. Microscopic changes in liver tissue were seen. Two rabbits injected with 150 mg Senecio pyrrolizidine alkaloid/kg body weight died in less than 24 hours. The resistance of the rabbit to chronic Senecio intoxication, but not to injected alkaloid, suggests that alkaloid absorption may be low in this species.

Animals↗

Dietary selenium status and pyrrolizidine alkaloid metabolism in vitro by rat liver microsomes.

The effect of dietary selenium status on the metabolism of pyrrolizidine alkaloids (monocrotaline, and mixed pyrrolizidine alkaloid from Senecio jacobaea) by rat liver microsomes in vitro was studied. In two experiments, there was no difference in the rate of metabolism of alkaloid by microsomes from selenium deficient or selenium supplemented rats. Selenium deficiency was confirmed by measurement of erythrocyte glutathione peroxidase. Administration of excess selenium by i.p. injection did not affect alkaloid metabolism. It was concluded that dietary selenium status was unlikely to influence the metabolism of pyrrolizidine alkaloids.

Animals↗

Growth of Aureobasidium pullulans on straw hydrolysate.

Growth characteristics and cell properties of Aureobasidium (Pullularia) pullulans were studied. The organism grew well on an acid hydrolysate of ryegrass straw over a wide range of pH and temperature. The optimum temperature and pH for the growth of the organism were 32 degrees C and 5.5, respectively. A cell yield of 1.5 g/liter of straw hydrolysate was obtained. The dried cell mass contained 42.6% crude protein, 0.4% crude fat, and 6.4% nucleic acids. The essential amino acid profile of the microbial protein was comparable to that of Candida utilis. A rat feeding study indicated that the A. pullulans cells were not toxic and that the feed intake, weight gain, and protein efficiency ratio values were superior to those obtained with C. utilis. Once the question of mathogenicity is resolved, A. pullulans could be useful for production of single-cell protein from cellulosic wastes.

Animal Feed↗

Nutrition of the domestic rabbit.

Recent studies on the nutritional needs of the rabbit were reviewed. Emphasis was placed on fiber utilization by rabbits, digestibility of forage protein, and unique aspects of mineral and vitamin requirements. In spite of the herbivorous nature of rabbits, their ability to digest fiber is low. Indigestible fiber may have a role in preventing enteritis. While lacking the ability to efficiently digest fiber, rabbits do make efficient use of forage protein, in contrast to most other monogastric animals. Differences in serum calcium homeostasis and calcium excretion as compared with other animals were discussed. The interrelationship between vitamin E and selenium appears different in the rabbit compared with other species. The limited information available on rabbit nutrition suggests that rabbits are unusual in their metabolism of several nutrients; because of their wide use in biological research, more extensive information on nutritional and metabolic characteristics of rabbits is needed.

Animal Feed↗