Determination and Prediction of Amino Acid Digestibility in Rapeseed Cake for Growing-Finishing Pigs

Area of Science:

• Animal Nutrition
• Feed Science
• Digestibility Studies

Background:

• Rapeseed cake is a valuable protein source for pigs, but its nutritional value can vary significantly.
• Understanding the digestibility of crude protein (CP) and amino acids (AA) is crucial for optimizing pig diets.
• Variability in rapeseed cake composition necessitates predictive models for accurate nutritional assessment.

Purpose of the Study:

• To determine the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in 10 diverse rapeseed cake samples.
• To develop predictive models for the SID of CP and AA based on the chemical composition of rapeseed cakes.
• To identify key chemical components influencing the SID of CP and AA in pigs.

Main Methods:

• Utilized 22 cannulated pigs in an 11x3 incomplete Latin square design.
• Included an N-free diet and 10 diets with varying rapeseed cake inclusion.
• Employed titanium dioxide as an indigestible marker for calculating ileal CP and AA digestibility.

Main Results:

• Observed high coefficients of variation (>10%) for crude fat, crude fiber, NDF, ADF, and TGS in rapeseed cake samples.
• Reported SID values for CP, Lysine (Lys), Methionine (Met), Threonine (Thr), and Tryptophan (Trp) ranging from 63.01% to 94.43%.
• Developed predictive models: SIDCP = 90.124 - 0.54NDF (R² = 0.58), SIDLys = 100.107 - 1.229NDF (R² = 0.94), SIDVal = 151.012 - 2.990TGS (R² = 0.57).

Conclusions:

• Significant variation exists among different rapeseed cake samples impacting nutrient digestibility.
• Neutral detergent fiber (NDF) and total glucosinolates (TGS) are identified as key predictors for SID of CP and AA.
• Heating temperature, alongside NDF and TGS, can be utilized to predict the SID of CP and AA in pigs.