Lipid coating as a mode of protecting free methionine from ruminal degradation

A method of protecting free methionine from partial ruminal degradation utilizing a lipid-protein matrix was developed. Eight wether lambs were fitted with abomasal cannulae and utilized in a 4 X 4 Latin square design experiment to determine the effectiveness of the protection matrix. The squares were blocked by animal and time, with each animal receiving each of the four diets. The diets were: (1) a negative control tall fescue and corn-based diet containing no added methionine; (2) a positive control diet that contained 3 g of methionine with ground corn, zein, coconut oil and methionine each added individually; (3) the control diet 1 supplemented with a methionine, ground corn, zein and coconut oil matrix that provided 3 g methionine/d; and (4) the control diet 1 containing the methionine matrix to provide 6 g methionine/d. Digestibility and balance data were obtained by collecting feces and urine over a 7-d period, followed by a day of blood sampling at 2, 4 and 6 h postfeeding. Abomasal samples were then subsequently collected over 3 d on a time schedule that represented every 2 h. Feeding protected methionine decreased (P less than .08) urinary N by .69 g/d and increased (P less than .08) N retention by 1.07 g/d. Plasma urea N was decreased (P less than .003) by 2.06 mg/100 ml and plasma free methionine increased (P less than .001) by 1.94 mumol/100 ml in lambs fed the protected methionine matrix. These data indicate that coating free methionine with the preparation described herein was partially effective in delivering methionine to the absorptive sites and subsequently to the tissues of the ruminant animal.