AZOMITE on Pelletization Characteristics – Study Notes

• Conditioning Temperature: Higher temperatures improve pellet formation, reduce Understanding Pellet Production: Key Objectives

  • Aim: Evaluate the influence of AZOMITE (AZ), feed ingredients (DDGS, MBM), and conditioning temperature on pellet mill throughput (production rate in MT/h) and pellet durability (PDI).

  • Core Challenge: Maximize throughput without compromising PDI. Note that AZOMITE may offset negative DDGS effects. Conditioning temperature is a major factor.

  Designing the Experiment: Factors and Analysis

  • Design: Factorial experiment with a randomized complete block design involving $2 \times 2 \times 2 \times 3 = 24$ treatments.

    • Factors: Conditioning temperature ($82.2^{\circ}C$ or $87.8^{\circ}C$), DDGS (0% or 8%), MBM (0% or 4%), and AZ (0%, 0.25%, or 0.50%).

  • Control: Use repeated days as a random effect to control variability.

  • Analysis: JMP for fixed effects (main effects and interactions) and random effects (day). Tukey’s HSD for post-hoc comparisons. Significance at P < 0.05.

  • Goals: Identify main effects, interactions, and conditions where AZ offsets DDGS or MBM.

  Formulating the Diet: Composition and Targets

  • Basal Diet: Corn and soybean meal-based, with fixed mixer-added fat ($1.5\%$ soybean oil), formulated for broiler grower lysine and ME.

  • Ingredient Mix (Examples):

    • Control: Corn (68.12%), soybean meal (26.92% for 46% CP).

    • 8% DDGS: DDGS (9% fat).

    • MBM: 4% MBM (58% CP).

    • AZOMITE (AZ): 0%, 0.25%, or 0.50%.

  • Nutrient Targets: Digestible lysine ($0.95\%$ constant), calculated AME (e.g., $3109$ kcal/kg for Control), CP, available P, Ca, Na.

  • Enzymes: Phytase ($500$ FTU/kg) and xylanase ($16,000$ BXU/kg) included.

  Pelleting Manufacturing and Sampling

  • Facility: Auburn University feed mill, Good Manufacturing Practices.

  • Batching: 1,818 kg basal diets, split into 455 kg batches for AZ integration.

  • Mixing: Twin shaft mixer (30 s dry; 120 s wet after $1.5\%$ oil).

  • Pelleting Process:

    • Conditioning time: 45 s.

    • Die: $4.4 \times 35$ mm.

    • Pellet mill: Model 1112-4, California Pellet Mill Co.

    • Operating conditions: steam pressure $30$ psi; motor load $40\%$.

  • Sampling: Three samples per treatment every 3 minutes for production rate. Six samples per treatment for PDI (ASABE S269.5 tumbler and Holmen tester).

  • Particle Sizes: SBM $\approx 934 \mu m$; DDGS $\approx 382 \mu m$.

  Measurements and Response Variables

  • Primary Responses: Production rate (MT/h) and PDI.

  • Observation: Throughput and PDI are typically inversely related; modifications can offset negative effects.

  Statistical Analysis Details

  • Model: Fixed effects for main factors and all interactions; repeated day as random effect.

  • Significance: P < 0.05.

  • Post Hoc: Tukey’s HSD.

  • Sample Sizes: Production rate N=144; PDI N=288.

  Results: Main Effects on Production Rate and PDI

  • Production Rate (MT/h):

    • Higher conditioning temperature ($87.8^{\circ}C$) increases rate by $\approx 11\%$.

    • 8% DDGS and 4% MBM reduce production rate.

    • 0.25% and 0.50% AZ increase production rate, especially with DDGS.

  • PDI (Pellet Durability Index):

    • Higher conditioning temperature increases PDI.

    • MBM and AZ have no significant effect on PDI.

    • 8% DDGS reduces PDI (P < 0.05).

  • Key Interactions (Production Rate):

    • DDGS $\times$ AZ is significant ($P = 0.0017$).

    • DDGS $\times$ MBM $\times$ AZ is significant ($P = 0.0322$).

  • Interaction Interpretation: AZ mitigates negative DDGS effects on production rate; 0.50% AZ can restore rate with 8% DDGS. With 8% DDGS and 4% MBM, 0.25% AZ is often effective in increasing throughput.

  Results: Pelleting Quality (PDI) Details

  • PDI improves with higher conditioning temperature.

  • AZ and MBM do not significantly affect PDI.

  • 8% DDGS reduces PDI (P < 0.05).

  • AZ improves throughput without sacrificing PDI, especially when DDGS or MBM are present.

  Mechanistic and Conceptual Insights

  • Cmash viscosity, and increase die pressure efficiency, leading to higher throughput and stronger pellets.

• DDGS: Reduces throughput and PDI due to fiber content, particle size, and energy requirements.

• MBM: Reduces production rate, possibly due to fat/protein interactions and energy loss.

• AZOMITE (AZ): As a pyroclastic aluminosilicate with anticaking properties, AZ may reduce die buildup and improve die scouring, aiding throughput. It maintains PDI while increasing throughput in DDGS/MBM diets at 0.25-0.50%.

Conclusions and Applications (Key Takeaways)

• Conclusion 1: Conditioning temperature increase from $82.2^{\circ}C$ to $87.8^{\circ}C$ improves pellet production rate ($\approx 11\%$) and PDI.

• Conclusion 2 & 3: MBM (4%) and DDGS (8%) reduce pellet production rate and DDGS (8%) reduces PDI.

• Conclusion 4: AZOMITE (0.25% and 0.50%) improves production rate with MBM (4%) and/or DDGS (8%). The strongest response is for 8% DDGS at 0.50% AZ, but 0.25% AZ is robust when both MBM and DDGS are high.

• Practical Implications: AZ can offset DDGS-related throughput declines while preserving PDI. Conditioning temperature is a critical lever. Variability in DDGS composition needs consideration.

Practical Notes and Context

• Relevance: Improves pelleting throughput and quality, reducing costs in broiler production.

• Environmental: Supports phosphorus management and phytase use by maintaining throughput with reduced inorganic phosphate reliance.

• Future Research: Explore AZ effects in different diets/phases, varying ingredient compositions, and its mechanistic role in die scouring.