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Title:Longitudinal muscle creatine concentrations and efficacy of dietary guanidinoacetic acid supplementation in pigs
Author(s):Zimmerman, Luke Alan
Advisor(s):Dilger, Ryan N
Contributor(s):Dilger, Anna C; Parsons, Carl M
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
PCr:ATP ratio
Abstract:With the world population growing and land resources limited, there is increasing demand for the agricultural sector to not only increase output, but also to improve production efficiencies. As production agriculture continues to drive for innovation in animal nutrition specifically, the use of feed additives offers a promising opportunity to reduce the cost of production and improve production efficiencies. Guanidinoacetic acid (GAA) has been evaluated as a feed additive in pigs. However, in order to further advance research around GAA supplementation, it is important to not only understand baseline levels of muscle creatine in pigs over time, but also how GAA supplementation impacts muscle creatine levels and muscle energetics. Two studies were conducted to further understand this area of research. Experiment 1 was a 15-week farrow-to-finish feeding experiment conducted with 5 feeding phases, in which an equal number of barrows and gilts were fed the same series of diets. Sixteen pigs were randomly selected for collection at 6 different time-points (0, 7, 21, 35, 63, and 104 days of age) throughout the experiment and muscle, kidney, liver, and blood samples were collected and analyzed for creatine-related metabolites. A clear baseline of muscle creatine levels over time was established which indicated that muscle creatine decreases shortly after birth, after which it increases (P < 0.001) through the finishing phases. Relative to creatine concentrations at birth, creatine in the liver, kidney, and blood plasma increased (P < 0.05) through 21 days of age. For Exp. 2, an arginine-adequate diet (0.92% digestible Arg) based on corn, soybean meal, whey protein concentrate, and lactose was supplemented with 0, 0.12, or 0.36% GAA to produce 3 experimental diets. Starting at 21 days of age, these 3 diets were then fed to 16 replicate pens with 4 pigs per pen (2 barrows and 2 gilts; 6.65 ± 1.19 kg). Individual pig and pen feeder weights were recorded upon the initiation of the experiment and at each phase change to calculate growth performance. At 42 and 63 days of age, 1 pig per pen was randomly chosen for blood and tissue collection. While supplementing GAA had no effect on nursery pig growth performance (P < 0.05), both 0.12% and 0.36% levels of GAA increased (P < 0.001) the phosphocreatine to adenosine triphosphate (PCr:ATP) ratio at 42 days of age relative to the negative control (NC) PCr:ATP ratio values. Guanidinoacetic acid supplementation also increased (P < 0.05) muscle, liver, kidney, and blood plasma creatine levels relative to the NC at both 42 and 63 days of age. These data suggest that GAA supplementation is effective in increasing the concentration of creatine in the muscle by increasing PCr concentrations and provides additional energy by increasing the PCr:ATP ratio. This research not only sets a foundation for future work through a proven muscle biopsy collection method, but also provides a baseline of muscle creatine levels. Finally, it opens the door for future research in the area of GAA supplementation by successfully demonstrating that GAA supplementation influences muscle creatine concentrations and provides an increased potential for energy expenditure within the pig by increasing PCr:ATP ratios.
Issue Date:2021-12-08
Rights Information:Copyright 2021 Luke Zimmerman
Date Available in IDEALS:2022-04-29
Date Deposited:2021-12

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