All experiment procedures were approved by the Animal Care Advisory
Committee of Sichuan Agricultural University. Twenty four barrows
(Duroc × Large White × Landrace) with an average body weight
of 78.1 kg were randomly divided into three groups with 8 duplicates
of 1 each. Pigs were penned individually. The groups were then randomly
assigned to each of the three dietary treatments that consisted
of a control diet (basal diet) and a control diet supplemented with
300 mg or 600 mg RES per kg of feed. The basal diet was formulated
to meet or exceed the NRC (1998) recommendation for the nutrient
requirements of 75–100 kg finishing pig. Compositions and calculated
nutrient contents of the basal diets were presented in Table 1. RES
was added to the basal diet at the expense of corn starch. The trans-
RES was provided by Ci Yuan Biotechnology Co. Ltd. (Xi'an, Shanxi,
China) and was extracted from Polygonum cuspidatum, and the purity
was 98.1% measured by HPLC. Pigs were provided ad libitum access to
feed and water throughout the trial period. Diets were fed for 49 days.
Individual body weight and feed intake were measured at the end of
the experiment.