Comparing two techniques for viscosity measurements in poultry feedstuffs: does it render similar conclusions?

Area of Science:

• Animal Science
• Nutritional Science
• Food Science

Background:

• Intestinal viscosity impacts nutrient digestion and absorption in poultry.
• Traditional viscosity measurements often remove particles via centrifugation, potentially underestimating true viscosity.

Purpose of the Study:

• To compare two in-vitro viscosity measurement techniques (Haake, without centrifugation; Brookfield, with centrifugation) for poultry feedstuffs.
• To assess the agreement between these methods in determining viscosity and identifying differences in feed ingredients and enzyme treatments.

Main Methods:

• Two sets of feedstuff preparations were used: milled feed combinations and enzyme-incubated ingredients (barley with beta-glucanases, soybean/sunflower meal with pectinases).
• Viscosity was measured using both Haake and Brookfield equipment at six time points.
• Lin's concordance correlation coefficient (CCC) evaluated agreement based on viscosity changes.

Main Results:

• Substantial agreement (66%) was found for milled feedstuffs and good agreement (69%) for barley diets with beta-glucanases.
• Agreement was poor (2%) for soybean meal and fair (32%) for sunflower meal diets with pectinases, attributed to low viscosity variation.
• Despite methodological differences, both techniques identified distinct viscosity differences in poultry feedstuffs under tested conditions.

Conclusions:

• Both centrifugation and non-centrifugation viscosity measurement methods can yield similar conclusions for poultry feedstuffs.
• The choice of method may be less critical when identifying significant differences in feed viscosity.
• Further investigation is needed for low-viscosity mixtures and specific enzyme-substrate interactions.