Preliminary report on the development of some indices of relative nutritive value (RNV) of cereal and legume samples, applicable in the early generations of selection

Rapid screening methods for biuret nitrogen determination and fluorometric lysine estimation are described. While the biuret method has been found to be suitable for early generation screening for peptide nitrogen determination, fluorescence estimation of dansylated grain meal could be taken as a good index of available lysine in cereal and legume samples. The necessity of rapid and inexpensive tests for the determination of Relative Nutritive Value (RNV) in the advance generations of screening, is discussed. Preliminary data available on two such tests, utilizing protozoan Tetrahymena pyriformis W. and flour beetle Tribolium confusum Duval, indicated promise. Both techniques were tried on different cereal and legume samples. The relative lethality of beetle larvae and their nitrogen retention were taken as indices of RNV in legumes. Larval Nitrogen Retention Index (LNRI) of cereal samples was found to be dependent both on nitrogen content and on protein quality. It was concluded that both these organisms need to be further investigated for their potential as test animals for RNV determination in the advance segregating populations. (author)