Leslie P. Dryden

Efficiency of transfer of polyunsaturated fats into milk.

Polyunsaturated milk has been produced by feeding cows safflower oil enclosed in a casein coat protected with formaldehyde (SOC-F) or formaldehyde-treated soybean (SB) preparations. The efficiency of transfer of dietary 18∶2 ranged from 17 to 42% for various lots of SOC-F and was only 2–8% for SB (per cent transfer=18.2 in milk fat per dietary 18∶2×100). The 18∶2 content of the milk fat increased from basal levels of 2–3% of total fatty acids to 35% with certain SOC-F levels and 7% with SB. Major compensatory changes were noted in 14∶0 and 16∶0 fatty acids. Blood cholesterol, triglycerides and nonesterified fatty acids all increased markedly as cows were fed increasing amounts of SOC-F. There was no increase in cholesterol in the milk.

The Effect of riboflavin on the bacterial synthesis of vitamin B12-active material in the rat

Abstract On B 12 -deficient rations that contained levels of the other B vitamins which were much higher than those required for optimal growth, a large proportion of negative control rats grew at a rate nearly equal to that of their B 12 -fed littermates, while the others grew much more slowly. The average growth rate and the proportion of such fast-growing negative controls increased, in general, with increased concentrations of B vitamins in the ration. The feeding, to slow-growing negative controls on a high B vitamin diet, of a single small dose of feces from fast-growing negative controls on the same diet, brought about a markedly increased growth rate; inclusion of sulfasuxidine in the ration delayed this effect for several weeks in practically all cases. Feeding these feces to animals on moderate levels of the B vitamins failed to bring about increased growth. These results indicated bacterial synthesis of B 12 -active material in the intestinal tract. Such synthesis was shown to be due to the high levels of dietary riboflavin. This finding is briefly discussed with regard to recent investigations on the chemical structure of vitamin B 12 and on related biochemical studies.

Effect of triundecanoin upon lipid metabolism in the cow.

The effect of feeding an odd-numbered carbon triglyceride, triundecanoin, upon lactation in the cow was studied. This fat appeared to be subject to considerable degradation in the rumen. There was no indication, however, that it yielded any increase in relative propionate concentration. A large amount of the odd-numbered carbon triglyceride was rejected by the animals, with a general decrease in feed consumption and consequent reduced milk yield. Fat production was unchanged. Some undecanoate passed into the milk but only at a low rate. There was a large difference in animal response. Feeding triundecanoin protected from rumen degradation led to a much greater transfer of undecanoate to the milk, prevented a significant decline in feed consumption and milk yield, but did not affect the milk composition appreciably. Smaller increases were observed in the amounts of other odd-numbered carbon fatty acids in the milk.

Influence of Vitamin B12 Upon Vaginal Patency in the Rat

Summary The onset of sexual maturity in female rats, as measured by vaginal patency, was found to be delayed in vit. B12-dencient animals as compared to vit. B ^-supplemented littermates when their mothers were fed a B12-dencient ration during lactation. No such differences were observed when the mothers were fed B12 during lactation. The nature of the carbohydrate and protein in the ration was found to have an effect on the differences observed.