Interaction of dietary carbohydrate and fat on glucose metabolism in growing pigs

Authors: CLINE, PAUL - Christensen Farms; TSAI, TSUNG - University Of Arkansas; Lents, Clay; STELZLENI, ALEX - University Of Georgia; DOVE, C - University Of Georgia; AZAIN, MICHAEL - University Of Georgia

Submitted to: Domestic Animal Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2021
Publication Date: 8/13/2021
Citation: Cline, P.M., Tsai, T.C., Lents, C.A., Stelzleni, A.M., Dove, C.R., Azain, M. 2021. Interaction of dietary carbohydrate and fat on glucose metabolism in growing pigs. Domestic Animal Endocrinology. 78. Article 106655. https://doi.org/10.1016/j.domaniend.2021.106655.
DOI: https://doi.org/10.1016/j.domaniend.2021.106655

Interpretive Summary: Producers must manage replacement females, called gilts, to achieve optimum body composition as they enter the breeding herd in order to improve lifetime productivity of sows. A greater understanding of how dietary components interact to affect growth and metabolism of pigs is necessary to achieve this goal. Scientists studied how carbohydrate source and added dietary fat interact to affect metabolism in pigs during development. Carbohydrate sources that were high in fructose interacted with dietary fat to change glucose and insulin metabolism. Changes in glucose and insulin metabolism were linked to changes in body composition. This research provides important insight for swine nutritionists about how to formulate macronutrients in diets to optimize body composition of developing gilts.

Technical Abstract: Increased consumption of fructose has been suggested to be a contributing cause of the increased rates of obesity in humans. Rodent studies have shown an increase in de novo lipogenesis and decreased insulin sensitivity in response to feeding high levels of fructose, but it is unclear if these effects occur in the same progression in humans. We aimed to develop a swine model for studying changes in glucose metabolism and insulin resistance resulting from dietary carbohydrate alone or in combination with high dietary fat. Two experiments were conducted to determine if the source of dietary carbohydrate, with or without added fat, had an effect on body weight gain, glucose metabolism, or insulin response in growing pigs. In the first experiment, pigs (24 barrows, initial body weight 28 kg) were fed one of 4 diets in which the source of carbohydrate was varied: 1) 20% starch; 2) 10% glucose + 10% starch; 3) 10% fructose + 10% starch; and 4) 20% fructose for 9 weeks. There were no dif- ferences in growth rate or glucose clearance observed. Experiment 2 was conducted as a 3 ×2 factorial with the main effects of carbohydrate source (20% starch, glucose, or fruc- tose) and added fat level (0 vs 10%). Pigs (24 barrows, initial body weight 71 kg) were fed one of 6 experimental diets for 9 weeks. Compared to the other dietary treatments, pigs fed fructose with high fat had an elevated glucose area under the curve during the GTT (Carbohydrate x Fat interaction, P < 0.01). This same group had a lower insulin response (Carbohydrate x Fat, P < 0.05). This work demonstrates that pigs can be a viable model to assess the long-term effects of dietary carbohydrates on metabolism and body composition. Studies of longer duration are needed to determine if these changes are indicative of insulin resistance.