Finishing pigs that are divergent in feed efficiency show small differences in intestinal functionality and structure

Area of Science:

• Animal Science
• Genetics and Genomics
• Digestive Physiology

Background:

• Residual Feed Intake (RFI) is a key trait for feed efficiency in pigs.
• Previous studies present conflicting data on the relationship between RFI and intestinal characteristics.
• Understanding these variations is crucial for optimizing swine production.

Purpose of the Study:

• To investigate differences in visceral organ size, intestinal morphology, enzyme activity, integrity, and gene expression between low and high RFI pigs.
• To assess the influence of geographical location on these intestinal traits.
• To clarify the contribution of intestinal factors to RFI variation in pigs.

Main Methods:

• Pigs (n=369) were ranked for RFI; low and high RFI groups were selected from Austria, Northern Ireland, and Republic of Ireland.
• Visceral organs and intestinal tissues were sampled around day 110 for morphological and enzymatic analyses.
• Gene expression related to innate immunity (TLR4, TNFA) was analyzed.

Main Results:

• Overall, RFI rank had minimal impact on intestinal size, structure, and function.
• Low RFI pigs showed some indicators of enhanced digestion and absorption (shorter crypts, higher duodenal enzyme activity, greater permeability), particularly in Austrian pigs.
• Geographical location exhibited a greater influence on visceral organ size and intestinal traits than RFI rank.

Conclusions:

• Intestinal size, structure, and function do not significantly contribute to the variation in RFI in pigs.
• Local environmental factors associated with geographical location play a more substantial role in shaping intestinal characteristics than RFI.
• Findings suggest potential subtle differences in innate immune response between low and high RFI pigs, warranting further investigation.