112 Dietary supplementation with 0.1% and 0.2% creatine does not improve the growth of postweaning piglets with normal birth weights.

Abstract Creatine is highly abundant in piglet skeletal muscle (40–45 mM). The present study tested the hypothesis that dietary supplementation with creatine improves the growth of postweaning piglets with normal birth weights (NBW; 1.25 to 1.55 kg). One-hundred and five (105) piglets (the offspring of Yorkshire × Landrace sows bred to Duroc boars) were weaned at 28 d of age with a mean body weight (BW) of 7.20 kg and a mean body length (BL) of 68.7 cm. The piglets were assigned randomly into one of the three groups (7 pens/group, 5 piglets/pen) to receive dietary supplementation with either 0.0%, 0.1%, or 0.2% anhydrous creatine. The corn- and soybean meal-based diet did not contain creatine, creatinine, or creatine phosphate. Based on the feed intake of 28- to 42-d-old weaned piglets (~3.5% of BW), these doses were equivalent to the dietary provision of 0, 36, and 72 mg creatine/(kg BW·d), respectively. All piglets had free access to their respective diets and drinking water. The BW and feed intake of piglets were recorded at d 0, 7 and 14 of the trial. On d 14, blood samples (3 mL) were collected from the jugular vein of piglets into heparinized tubes at 1 h after food was removed. Plasma was analyzed for creatine and and related metabolites by HPLC. Data were statistically analyzed by one-way ANOVA and the Student-Newman-Keuls multiple comparison test, with pen being the experimental unit. On d 14 of the trial, in the control group, the BW and BL of piglets were 9.83 ± 0.10 kg and 81.0 ± 0.6 cm (mean ± SEM, n = 7 pens), respectively, and the concentrations of creatine and creatinine in plasma were 211 ± 6.2 µM and 29 ± 0.9 µM (mean ± SEM, n = 7 piglets), respectively. During the 14-d period, the average daily weight gain, average daily feed intake, and gain:feed ratio (g/g) of piglets in the control group were 188 ± 6.3 g/d, 35.1 ± 2.2 g/(kg BW·d), and 0.638 ± 0.025 (mean ± SEM, n = 7 pens), respectively. Compared with the control group, dietary supplementation with 0.1% and 0.2% creatine dose-dependently increased (P < 0.05) the concentrations of creatine plus creatinine in the plasma of piglets by 25% and 40%, respectively, but did not affect (P > 0.05) their daily weight gain, BW, BL, feed intake, or gain:feed ratio. In piglets fed the basal diet, 10%, 21%, and 49% of the dietary glycine, arginine, and methionine entering the portal vein were used for creatine synthesis, respectively, and 65% of the methionine metabolized via the transsulfuration pathway was recycled for creatine synthesis. We conclude that dietary supplementation with up to 0.2% creatine does not improve the postweaning growth of NBW piglets fed a corn- and soybean meal-based diet. Endogenous synthesis of creatine can support its provision to these piglets under the experimental conditions used. (Supported by the Texas A&M Hagler Fellow Program and Texas A&M AgriLife Research H-8200)