Dietary selection for lysine by piglets at differing feeding regimen

Article history: Received 14 August 2007 Revised 10 September 2008 Accepted 10 September 2008 The aim of the present study was to investigate preferences of piglets for diets varying in lysine (Lys) concentration andwhether those preferences are influenced by changing position of diets on offer in feeders. For this purpose, a feeding trial was carried out over a period of 5 weeks. Piglets (equal proportions of barrows and gilts) with an initial BW of 7.4±0.9 kg were randomly subdivided into four groups of 12 pigs each and were housed in single pens. Two reference groupswere fed diets containing either 0.7% Lys (low-Lys group) or 1.0% Lys (high-Lys group). Two other groups had the choice from two diets containing 0.7 or 1.0% Lys offered simultaneously in identical feeders. For animals of one of these choice groups (Lys-choice 1 group) the position of diets in the feeders remained unchanged throughout the experimental period, but for animals of a second choice group (Lys-choice 2 group) position of the diets on offer in the feeders was changed two times a week. Average daily feed intake and daily gainwere greatly (pb0.05) decreased in animals of the lowLys group compared to other treatments, and feed to gain ratio was increased. Performance of animals in Lys-choice 1 group was numerically decreased compared to animals of Lys-choice 2 group. Chosen diets of Lys-choice groups 1 and 2 contained on average 31 and 19% feed with 0.7% Lys, respectively. Resulting Lys contents of total diets were 0.94 and 0.98% for Lys-choice groups 1 and 2, respectively, as a mean of the experiment. In week 1 animals of both Lys-choice groupsmet approximately 50% of total feed intake by consumption of the 0.7% Lys diet. Animals of Lys-choice 1 group lowered this portion to 20% in the last experimental week and animals of Lys-choice group 2 to 11%. Preference for the 1.0% Lys diet was evident (pb0.05) fromweek 3 to 5 in Lys-choice 1 group and from week 2 to 5 in Lys-choice 2 group. Piglets are able to distinguish between diets differing in Lys content and to prefer a better balanced diet over a Lys-deficient one. Changing the position of the diets on offer in the feeders two times a week does not impair the ability to select for a diet more adequate in Lys concentration, but led in contrary to a slightly higher preference for Lys. © 2008 Elsevier B.V. All rights reserved.