The effect on the protein quality of meat meals of processing them under commercial conditions in a continuous dry renderer at maximum temperatures ranging from 116 to 160°C for a running time of 115 min was studied. Although the total levels of amino acids were little affected by processing temperatures, the biological availability of all essential amino acids, as determined by the protozoan Tetrahymena pyriformis, was reduced as the processing temperature increased. At 140 and 160°C the availability of certain amino acids was reduced by 37-56%, lysine, histidine, and methionine being the most severely affected. The availability of essential amino acids in meals produced at temperatures from 121 to c. 138° was not significantly different. The growth-promoting ability of the meat meals for chickens was closely related to the availability of the essential amino acids.
__________________
*Part VI, Aust. J. Agric. Res., 19: 171 (1968).
Studies are reported on the blood levels of carbon tetrachloride following administration of 8 ml of the drug to sheep by ruminal, abomasal, and intramuscular routes. Absorption was most rapid with ruminal administration, slowest with intramuscular, and intermediate with abomasal administration. The drug could be detected in expired air within 5 min of administration. Peak levels in the blood of c. 16 to 20 pg per ml were reached, with ruminal and abomasal administration, at c. 15-30 min and 60-120 min respectively. With intramuscular administration the peak of c. 10 �g/ml was reached at about 4 hr. Undetectable levels, less than 5 pg/ml, were reached at c. P 5 hr with ruminal administration, 6-7 hr with abomasal administration, and c. 10 hr with intramuscular injection. Carbon tetrachloride could be detected in the expired air up to 40-60 hr after administration, depending on the route. The blood curves were not appreciably different whether the drug was administered in the pure state or in paraffin oil. Fasting for 48 hr also had no appreciable effect. Fat sheep showed lower levels and a longer period of excretion than animals in poorer condition, presumably owing to partitioning into adipose tissues.
Susceptibility of sheep to toxic effects of carbon tetrachloride (CCl4) was assessed by determining the increase in plasma levels of isocitric dehydrogenase (ICD) and glutamic transaminase (GOT) and by other criteria. Susceptibility was increased by oral administration of 1 mg of selenium (Se) as sodium selenite plus 100 i.u. of tocopherol acetate on alternate days for 120 days, 2 mg Se per day for 21 days, and 6 mg Se per day for 6 days, before dosing with CCl4. Susceptibility was reduced by smaller total amounts of Se, and by oral doses of 6 mg Se per day for 3 days, a single oral or intramuscular dose of 5 or 12 mg c. 20 hr, or 5 or 12 mg orally 10–20 min, before dosing with CCl4. One 5 mg dose at 20 hr and a second 20 min before CCl4 was more effective than either alone. Sheep from two different sources differed considerably in their susceptibility to CCl4. In the more susceptible sheep Se administration reduced susceptibility to a level comparable with that shown by the naturally resistant animals. Administration of Se to sheep dosed with CCl4 and then given a high-protein diet resulted in lower GOT levels, milder clinical signs, and a great reduction in mortality. In field tests on properties with a recent history of CCl4 poisoning, oral administration of 5 mg Se about 20 min before CCl4 significantly reduced susceptibility. Administration of Se to fluke-infested sheep did not protect the liver fluke (Fasciola hepatica) against CCl4.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.