Interaction and imbalance between indispensable amino acids in young piglets

Area of Science:

• Animal Nutrition
• Swine Physiology
• Amino Acid Metabolism

Background:

• Reducing dietary protein in piglet feeds necessitates a thorough understanding of essential amino acid (AA) requirements and their interactions.
• Valine (Val) and tryptophan (Trp) are critical AAs, and their dietary balance influences piglet growth performance.
• Amino acid imbalances, particularly with excess isoleucine (Ile), histidine (His), and leucine (Leu), can impact growth in low-protein diets.

Purpose of the Study:

• To investigate the interaction between dietary valine (Val) and tryptophan (Trp) levels in post-weaning piglets.
• To evaluate the impact of amino acid (AA) imbalance, specifically excess Ile, His, and Leu, on piglet growth at different standardized ileal digestible (SID) Val levels.
• To determine optimal AA supplementation strategies for low-protein diets to support piglet growth performance.

Main Methods:

• Experiment 1 utilized a 2x2 factorial design to assess the effects of Val and Trp supplementation in a low-crude protein (CP) diet (17.7%).
• Experiment 2 employed a 3x2 factorial design to examine the influence of excess Ile, His, and Leu at varying SID Val levels (60% or 70% of SID lysine).
• Growth performance parameters including feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) were monitored throughout the studies.

Main Results:

• In Experiment 1, dietary Trp influenced FI, while both Trp and Val affected FCR. An interaction between Val and Trp was observed for BWG.
• Increasing dietary Val improved FI and BWG in Experiment 2, whereas excess Ile, His, and Leu reduced FI and BWG.
• Low-CP diets supplemented with adequate Val and Trp supported performance comparable to higher CP diets. AA excess negatively impacted growth independently of Val levels, except for FCR.

Conclusions:

• A significant interaction exists between dietary valine and tryptophan, affecting the zootechnical performance of post-weaning piglets.
• Excess dietary isoleucine, leucine, and histidine negatively impacts piglet growth performance in low-protein diets, irrespective of the dietary valine level.
• Optimizing essential amino acid balance is critical for maximizing growth and feed efficiency in piglets fed reduced-protein diets.