WELL-FED PIGLETS PREFER AMINO ACIDS THAT ELICIT UMAMI TASTE

Pigs perceive the umami taste via the pT1r1/pT1r3 receptor present in their tongue. In vitro studies, using a proprietary cell reporter system (CRS) that expresses this heterodimer, showed that it is tuned to detect amino acids (AA). The objectives of this work were (1) to evaluate preferences of piglets for AA and (2) to correlate preference data with outcomes from the CRS for the same AA. Forty-eight weaned piglets (10.7±1.20 Kg of BW, mixed sexes) were distributed in pairs/pen, with ad libitum access to water and pelleted starter feed (2521Kcal NE pigs*Kg-1, 191.40g*Kg-1 CP, 13.20g*Kg-1 Lys). Preferences were assessed using a double-choice model that consisted of 10-min training sessions conducted twice daily (9AM, 12PM) over 2 consecutive days followed by 2-min test sessions conducted twice daily (9AM, 12PM) over 5 days. During training, plain and sweetened (500mM sucrose) water were offered simultaneously in stainless steel containers (250g/container); whereas, in test sessions, water was offered along with water (control) and 50mM solutions of monosodium glutamate (MSG), D,L-Met, Gly, L-Ala, L-Gln, L-Glu, L-Lys, L-Thr and L-Trp. Preference (%) data [g test solution / (g test solution + g water) x 100] were analyzed using a mixed model approach that included the effects of pen (random), day, time, and treatment. Preferred solutions (P<0.01) were MSG (79.6±2.03), Glu (79.8±2.45), Lys (77.2±3.91), Gln (73.4±3.37) and Ala (67.6±4.46), whereas Trp (25.6±4.40) was rejected. Additionally, solutions of Met (64.4±9.58), Gly (59.9±4.41) and Thr (49.5±10.05) were not different from control (46.1±3.18). Results from CRS were positively correlated (R=0.92, P<0.05) with preferences of Ala, Gln, Glu and MSG. Lys was also preferred but did not stimulate the umami receptor. In summary, well-fed piglets mainly preferred AA that stimulated the umami taste receptor expressed in the CRS. Therefore, the umami taste has a positive hedonic (pleasant) valence (value) for pigs. tech.service.fad@lucta.com