Use of Plasma and Egg Yolk Biotin of White Leghorn Hens to Assess Biotin Availability from Feedstuffs

A linear relationship (r greater than .98) was found between the level of dietary biotin and plasma and egg-yolk biotin in White Leghorn hens after feeding the experimental diets for 2 weeks. This shows high reliability of these parameters as indicators of biotin availability. When plasma and egg yolk biotin were used to assess biotin availability in feedstuffs, they indicated low values for wheat (0%) and sorghum (10 to 20%) and high values for corn (75 to 100%), soybean meal (100%), and meat and bone meal (85%). When these parameters were used to assess commercial poultry diets, they indicated values for a "layer" diet of 75 to 100% and for a "broiler" diet of 81 to 92%. Pelleting gave an increase in biotin availability of 10% over the mash diet. This method for assessing biotin availability promises to be simple, economic, rapid, and reliable.