Pigs Ferment Enzymatically Digestible Starch when it Is Substituted for Resistant Starch

Area of Science:

• Animal Nutrition
• Digestive Physiology
• Swine Production

Background:

• Feeding behavior is regulated by satiety mechanisms influenced by resistant starch (RS) intake.
• Adaptation to RS intake may involve shifts between starch digestion and fermentation processes.

Purpose of the Study:

• To investigate how growing pigs adjust their feeding behavior in response to varying dietary RS concentrations.
• To understand the adaptation dynamics when transitioning between high and low RS diets.

Main Methods:

• Pigs were fed diets with high-amylose maize starch (high RS) or waxy maize starch (low RS) over 28 days.
• Dietary RS levels were titrated upwards (LH) or downwards (HL), with a control group.
• Feeding behavior, starch digestion, and fermentation were evaluated, with responses analyzed via linear regression.

Main Results:

• Increasing resistant starch (RS) increased starch fermentation, particularly in pigs transitioning from low to high RS (LH).
• Feed intake and meal size decreased in LH pigs as RS increased, correlating with fermentation response.
• Pigs transitioning from high to low RS (HL) showed attenuated fermentation and no significant changes in feed intake.

Conclusions:

• Pigs adapt more slowly to digestible starch than to RS, leading to fermentation of digestible starch when transitioning from high to low RS diets.
• Feed intake is driven by the adequacy of adaptation to RS, not RS concentration alone.
• Diet history significantly influences nutrient digestion and feeding behavior in pigs.