Intra-gastric protection of vitamin A orally dosed in coconut oil to ruminant animals

Experiments were conducted to improve dietary supplementation of vitamin A to ruminants. Abomasal digesta was collected 24 h after oral administration of vitamin A (240,000 IU) and chromic oxide to mature sheep. Comparisons of vitamin A to chromic oxide ratios in abomasal digesta to intake ratios were used to estimate abomasal recovery of orally dosed vitamin A. Treatment of diet with monensin (22 ppm, 10 days) or inclusion of sucrose in a meal (25 g) consumed 1 h prior to vitamin A dosage did not alter abomasal recovery of vitamin A. Vitamin A recoveries were higher when vitamin A was suspended in 11.7 g of coconut oil compared to safflower oil. Amount of vitamin A escaping preabomasal degradation increased linearly with carrier coconut oil (0, 11.7, 23.5 and 35.0 g). When vitamin A and 23.5 g of coconut oil were administered simultaneously, but in separate capsules, recoveries were unchanged from controls indicating physical contact between carrier oil and vitamin A is required to minimize intra-gastric degradation. Vitamin A was not protected when suspended in hydrolyzed coconut oil (27 g) indicating stability of the triglyceride ester linkages in the carrier coconut oil may be important. Abomasal recovery of vitamin A when sheep consumed long fescue hay was greater when vitamin A was suspended in coconut oil. Vitamin A delivered in coconut oil underwent greater degradation when sheep consumed ground versus long fescue hay indicating coconut oil was less protective or greater degradation occurred when sheep consumed finely ground hay diets. A concluding experiment tested blood response to vitamin A suspended in coconut oil. Blood was collected from yearling wethers via arterial catheters at times 0, 16, 20, 24, 28, 32 and 36 h after dosing vitamin A (35,000 IU). Serum vitamin A concentration was significantly above base level at sampling hours 16 through 28 when vitamin A was pre-dissolved in coconut oil (35 g). In contrast, blood vitamin A levels did not change significantly when vitamin A was supplemented without coconut oil. Increased appearance of vitamin A in the serum subsequent to oral delivery in coconut oil may be accounted for by findings of increased abomasal recovery of dosed vitamin A without indication of interference with vitamin A absorption.