# Determination and prediction of amino acid digestibility in rice bran for growing pigs

## TL;DR

This study measured how well pigs can digest amino acids in rice bran and developed models to predict digestibility based on rice bran's chemical makeup.

## Contribution

The study introduces predictive models for amino acid digestibility in rice bran using its chemical composition.

## Key findings

- Rice bran sources showed significant variability in chemical composition.
- Prediction equations for amino acid digestibility achieved high R² values, especially for lysine and threonine.

## Abstract

This experiment was conducted to determine the apparent ileal digestibility or standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in 10 rice brans fed to pigs, and to construct predictive models for the SID of CP and AA based on the chemical composition of rice bran.

Twenty-two healthy (Duroc×[Landrace×Yorkshire]) pigs equipped with ileal T-cannulas (initial body weight: 30±1.5 kg) were selected for this experiment. A replicated 11×3 incomplete Latin square design was adopted. The experiment consisted of 3 periods each lasting for 7 days and had 11 dietary treatment groups. The diets included 10 rice bran diets as well as a nitrogen-free diet for determining endogenous losses of AA, and each treatment group had 6 replicates. Titanium dioxide was added to each diet as an indicator at a concentration of 0.3%.

Except for dry matter (DM) and total phosphorus (TP), the coefficients of variation for the chemical components among 10 rice bran sources were all greater than 10%. The SID of CP, Lys, Met, Thr, and Trp in rice bran was 81.89%±6.23, 80.33%±2.21, 83.25%±5.51, 79.89%±5.68, and 72.12%±4.71, respectively. The best prediction equations for the SID of CP and four limiting AA in rice bran are as follows: SIDCP = 974.032–29.805TP–9.496DM (R2 = 0.88), SIDLys = 471.278–9.267TP–4.245DM+1.401dummy variable (R2 = 0.92), SIDMet = 122.281–2.712CP (R2 = 0.51), SIDThr = 51.864+2.204GE–1.324CF ([R2 = 0.97]; GE, gross energy; CF, crude fiber), and SIDTrp = 73.912–23.268Calcium–0.336NDF+0.318TS ([R2 = 0.96]; NDF, neutral detergent fiber; TS, total starch).

There was significant variability among the chemical components of 10 different sources of rice bran. Moreover, GE, DM, CP, TP, TS, CF, and NDF could serve as crucial predictors for the SID of AA.