Taste preferences for amino acids in the house musk shrew, Suncus murinus

Taste preferences in house musk shrews for amino acids as well as NaCl, sucrose, quinine hydrochloride, HCl and saccharin Na were studied by employing the two-bottle preference technique. Shrews showed a preference for 0.2--05. M sucrose but a moderate rejection to NaCl and a strong rejection to quinine, HCl and saccharin. They exhibited a marked preference for many naturally occurring L-alpha-amino acids with aliphatic side chains at both 0.02 and 0.2 M. Increase in the aliphatic side chain length of DL-alpha-amino acids resulted in both lowering of the preference threshold and increase in the preference magnitude. Amino acids with side chains containing sulfur atoms, basic groups and Phe at 0.02 M were preferred to water, but Cys and Arg at 0.2 M was rejected. Shrews showed neither preference nor rejection to Trp, Asn, Gln and monosodium glutamate at 0.02 M, but rejected strongly Asp and Glu. D-Met from 0.001 to 0.1 M was preferred as well as L-Met, while D-Phe was more preferred than L-Phe. Such preferences for a wide variety of amino acids in shrews could be attributed to their food habit of predating on various kinds of insects and worms.