DIETARY PREFERENCES OF ACIDS AND SALTS IN PIGLET DIETS

Compromised voluntary feed intake of piglets in the post-weaning period might be improved by increasing feed palatability. Eighteen double choice tests with a total of 600 post-weaned pigs (20–25 kg BW), were conducted to determine preference for 14 acids and 4 salts compared with a control (REF) diet. Each test was performed using 8 or 9 pens (replicates) of 3–4 pigs that were offered simultaneous access to 2 feeding hoppers (REF diet or diet containing one of the products (AC) being tested). Each test was performed during 3 consecutive 4d-periods, in which low, medium and high inclusion rates of the AC were evaluated, respectively. The AC were tested at 0.5, 1 and 1.5% of inclusion, except for benzoic and succinic acids that were tested at 0.25, 0.5 and 1%, and potassium diformate that was tested at 0.5, 1 and 2%. The preference for each AC and dose compared with REF was calculated as the percentage contribution of the AC diet to total feed intake. Mean preference values were compared with the neutral value of 50% using the Student’s t-test. Values are presented in brackets ordered by increasing doses and those with an asterisk are significantly (P < 0.05) different from 50%. Acids that improved feed preference (%) include the medium doses of citric (59.0, 69.8*, 56.8) and tartaric acids (54.2, 73.4*, 67.5) and the high doses of potassium diformate (57.2, 58.5, 65.9*) and sodium propionate (55.1, 58.1, 58.2*). There were no significant effects on feed preference with ascorbic (47.8, 49.6, 41.9), benzoic (45.0, 48.4, 50.8) and malic (50.0, 48.9, 34.8) acids or sodium butyrate (42.4, 51.1, 48.3). Finally, negative effects on feed preference were found with all the doses of acetic (32.5*, 29.9*, 16.6*) and caproic (29.1*, 27.8*, 22.1*) acids and some doses of butyric (35.9, 43.5, 21.2*), caprilic (33.0, 33.2*, 14.7*), formic (39.9, 35.6*, 24.9*), lactic (51.3, 38.4, 35.6*), phosphoric (28.9*, 34.4*, 35.6), propionic (52.1, 37.0, 25.6*) and succinic (36.9*, 41.6, 51.9) acids and calcium formate (29.9*, 35.8*, 38.1). We conclude that some AC significantly affect feed preference in pigs. tech.service.fad@lucta.com