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Male rats weighing 100 g were used in a 19-day trial. The rats received diets containing varying proportions of methionine. Their absolute liver weight was lower, due to the high methionine levels, than that of the animals fed optimum rations, whereas the relative liver weight was found to be lower only in the pair-fed group. No essential differences were observed between the levels of dry matter, protein, and fat. Glycogen levels were found to be lowered only in cases when high methionine doses were administered. Pathologically low levels of glycogen were found in animals of the pair-fed group. High methionine consumption reduced the percentages of 12 glucogenetic amino acids in the liver. This, in turn, suggests an increased rate of glucose formation from amino acids, a process which was not observed in animals of the pair-fed group. High methionine doses produced a condition of hyperglycaemia, while in the pair-fed group hypoglycaemia was observed. The highest rate of secretion of thyroid hormones was found in animals receiving the optimum ration; a lower rate of secretion was observed in the animals consuming less or more methionine. In animals receiving high methionine levels the rate of hormone secretion decreased in a stepwise manner with increasing methionine supplementation. Only the highest methionine doses (5,3%) were found to have a negative effect on the maximum rate of iodine incorporation into the thyroid gland. These findings were also substantiated by histological investigations because a true pathological picture was only found in histological sections of thyroid tissue from animals fed the highest methionine doses (5,3%) The thyroid tissue of these animals consisted predominantly of small glandular alveoli whose colloid was slightly coloured. The epithelial cells of these alveoli were degenerated; some cases of liver cell disintegration and, more rarely, cellular necrosis were noted.

In order to find out how short-time denutrition changes the concentration of some substances in the rumen fluid and the blood, tests with full-grown sheep were carried out. Fodder was withheld from sheep with inserted Jarrett fistulae for 48 hours after normal feeding. After 48 hours the animals were given concentrated fodder, after 52 hours exclusively hay. From the 72nd hour onwards the animals were provided with fodder as usual. Samples of the rumen fluid and blood samples were taken at the beginning of the test, after the last normal feeding and then in the 24th, 32nd, 48th, 52nd, 56th, 72nd and 96th hour. We could find out that, during the 48-hour denutrition, the pH-value of the rumen fluid turned alkaline and the concentrations of ammonia, volatile fatty acids and lactic acid decreased. The protein metabolism underwent a rapid change in the organism. The protein content of the blood plasma decreased, above all the albumin content, as well as the concentration of glycoproteins and volatile amino acids. Among the various amino acids, the concentration of glycine increased highly, that of alanine and valine just slightly. The concentration of most amino acids decreased or--of some of them remained the same. Among the paramters that are characteristic of lipid and carbohydrate metabolism, the total content of lipids and cholesterin decreased, and so did the concentration of blood sugar, lactic acid and pyruvic acid in the blood plasma. The results indicate that short-time denutrition has a considerable influence on the rumen fermentation and the intermediary metabolism of ruminants. The quickly arising lack of energy of ruminants slows down the protein synthesis and increases the glyconeogenesis from amino acids. The tissue is supplied with energy by the mobilisation of lipids.