PS3-10. Effect of Different Concentrations of Lysine on Growth Performance, Nutrient Digestibility and Faecal Scores in Weaning Pigs

Amino acids (AAs) are fundamental nutrients required for the synthesis of proteins in pigs, playing a vital role in their growth, development, and overall health. Among these, lysine (Lys) is considered the most limiting AA in corn-soybean meal-based diets commonly used in pig production. Lys serves as a reference point for determining the requirements of other AA necessary for optimal pig performance. The balance of Lys in the diet significantly influences several physiological processes, including transporter protein abundance, nitrogen retention, and the turnover of body proteins. Both deficiencies and excesses of Lys can compromise these processes, leading to reduced growth rates, inefficient nutrient utilization, and suboptimal production outcomes. Therefore, this study was designed to investigate how varying dietary concentrations of Lys influence several key parameters in weaning pigs, including growth performance, nutrient digestibility, and fecal consistency. A total of 140 [Landrace ×Yorkshire] × Duroc) weaning pigs with an average initial body weight of 6.65 ±1.11 kg, were used in this experiment. The pigs were randomly assigned to four dietary treatments to ensure unbiased comparisons across the treatment groups. Each treatment included 7 replicates, with 5 pigs per pen, and the experiment lasted for a total of 5 weeks. The dietary treatments were NC (negative control) - 1.35 % Lys; PC (positive control- basal diet + 1.45% Lys); TRT1, basal diet + 1.55% Lys; TRT2, basal diet + Lys 1.65%. All data were processed by Duncan's multiple Range test using GLM procedure of SAS to test the significance between means. P < 0.05 was set as statistically significant. Pigs fed 1.65% of dietary Lys showed an increased body weight gain (P < 0.05) during week 5. The average daily gain (P < 0.05) from week 3 to week 5, overall daily gain and feed intake was increased (P < 0.05) in the complete experiment period. However, nutrient digestibility and fecal score had no significance. In summary, increasing dietary Lys concentration to 1.65% could be beneficial for enhancing growth efficiency during the weaning period.