The Effect of Soya-Phosphatides on the Absorption and Utilization of Vitamin A in Dairy Animals

Summary Twenty-six healthy pregnant dairy cows of the Jersey and the Holstein breeds were divided into three dietary groups approximately 30 days prior to parturition. Each group received the basic herd ration. Group I, consisting of ten cows, was again subdivided into two groups; Group I–A received no supplement and Group I–B the herd ration plus 10g. of soya-lecithin daily. Each of the eight cows in Group II was given one million I.U. of vitamin A (fish-liver oil) daily. Bach of the eight cows in Group III was fed one million I.U. of vitamin A and 10g. of lecithin daily. The supplements were continued up to the seventh day following parturition. Assays of blood vitamin A and carotene and of milk vitamin A, carotene and lecithin were made at intervals up to 21 days postpartum. Blood plasma vitamin A and carotene were determined in all calves, and representative animals were sacrificed at birth to determine vitamin A liver storage. At parturition the plasma vitamin A level in the control cows fell almost to half of the 4 weeks prepartum level. The level in the cows fed vitamin A supplements remained fairly high, especially for the cows fed lecithin plus vitamin A, indicating that lecithin enhanced the absorption of vitamin A. There was no significant effect of feeding lecithin without vitamin A, although the decrease in blood carotene following parturition appears to be about 10 per cent less when lecithin is fed. Blood plasma carotene was depressed in both vitamin A supplemented groups. However, when vitamin A was fed for a longer period, the carotene level was depressed still further in the cows fed lecithin along with vitamin A. These limited data indicate that lecithin enhanced the action of vitamin A in depressing the carotene level. The vitamin A in the colostrum of cows fed vitamin A was greater than that of the control group; when both lecithin and vitamin A were fed, the colostral vitamin A at the first milking was approximately double that of the vitamin A supplemented cows. This shows that lecithin, when added to vitamin A, increased the transmission of colostral vitamin A. The transmission of vitamin A and carotene in milk closely followed the trend found in the blood plasma. The lecithin content of milk was highest when lecithin was fed to the cows along with vitamin A, and a higher level was maintained in the normal milk. Feeding lecithin without vitamin A had no effect on the transfer of lecithin to milk. When both vitamin A and lecithin were fed, the lecithin of the colostrum and milk was increased. The blood plasma vitamin A level in the newborn calf was highest and the plasma carotene level was the lowest in the calves from dams fed both lecithin and vitamin A. The total liver storage vitamin A in the newborn calves from the control group was low-(190 γ ); it was 5,910 γ in the vitamin A supplemented group and 11,722 γ in the vitamin A plus lecithin supplemented group. Thus, the addition of lecithin to the vitamin A supplement remarkedly increased the liver storage. Three groups of five calves each were fed from birth to 7 days of age as follows: Group A, colostrum; Group B, skim milk plus the same daily quantity of total vitamin A consumed by the calves in the colostrum group (25,000-37,500 LU. of vitamin A); and Group C, skim milk plus the same quantity of vitamin A and the same quantity of lecithin (3-4.5g.) available in the colostrum given to Group A. Every calf in Group B developed serious scours from the third day. Two of them died on the seventh day and a third one on the eleventh day. Their blood plasma vitamin A level was much below that of the colostrum-fed calves. All the calves in Groups A and C grew quite well with slight evidence of digestive disturbance. Blood plasma levels in Group A and C were almost identical, showing the ability of lecithin to increase absorption and utilization of vitamin A.