Little has bren known about the sense of taste in pigs. Here taste recordin
gs were obtained from the chorda tympani (CT) and glossopharyngeal (NG) ner
ves of I to 7-week-old pigs. On the whole, the pig's taste acuity was found
to be high but quite different from that of humans and several laboratory
mammals. Acids elicited the largest response in the whole CT nerve whereas
bitter and sweet substances best stimulated the NG nerve. Among compounds s
weet to humans, glycine, xylitol, sucrose, fructose and glucose gave the la
rgest responses, while acesulfame-K, cyclamate, D-tryptophan, neohesperedin
dihydrochalcone (NHDHC), saccharin and stevioside gave a small response, a
nd alitame, aspartame, super-aspartame, and thaumatin elicited no responses
. Monosodium glutamate (MSG) and MSG mixed with guanosine 5'-monophosphate
(GMP) and inositine 5'-monophosphate (IMP) elicited large taste responses.
Betaine also stimulated somewhat. Tilmicosin(R), and quinine hydrochloride
(QHCl), gave large responses, while denatonium benzoate, one of the most bi
tter compounds known to humans, gave small responses. Hierarchical cluster
analysis of 49 single CT and 31 NG fibres separated four clusters of fibres
in the CT and in the NG. The H cluster, responding to acids, was the most
populous in CT. The second largest in the CT was the S cluster. In the NG t
he S cluster formed the largest group responding to carbohydrates, glycine
and xylitol, responding to some extent to acesulfame-K, stevioside and D-tr
yptophan, but very little or not at all to alitame, aspartame, cyclamate, N
HDHC, saccharin and thaumatin. The Q cluster, sensitive to QHCl, sucrose oc
taacetate and Tilmicosin, was the second largest cluster in NG. In addition
, the CT and NG contained clusters that responded best to MSG alone or MSG
with GMP or IMP. In contrast to findings in other species, pigs have few ta
ste fibres which respond to NaCl, LiCl and KCI and in addition these NaCl a
nd LiCl responses, when present, were unaffected by amiloride. This indicat
es that the pig has a low ability to taste NaCl. The results of this study
suggest that recordings from the taste nerves of the pig should be used fcr
screening of compounds that are under cons;deration for oral or ingestive
use in pigs.