Volatile Organic Compound Profiles Associated with Microbial Development in Feedlot Pellets Inoculated with Bacillus...

Area of Science:

• Animal Nutrition
• Microbiology
• Food Science

Background:

• Microbial contamination of animal feed generates microbial volatile organic compounds (mVOCs), altering odour and potentially affecting feed quality.
• Bacillus amyloliquefaciens strain H57 (H57) demonstrates potential for inhibiting microbial growth in animal feeds.

Purpose of the Study:

• To investigate the effect of H57 inoculation on the odour profile of stored feedlot pellets.
• To determine if H57 impedes the production of mVOCs, thereby preserving feed freshness.

Main Methods:

• Gas chromatography-mass spectrometry (GC-MS) was employed to monitor volatile organic compound (VOC) emissions from inoculated and un-inoculated feedlot pellets.
• Pellets were stored at ambient (22 °C) and cold (5 °C) temperatures for 3 months, with VOC analysis at 0, 1, 2, and 3 months.
• Principal component analysis (PCA) was utilized to analyze VOC profile changes over time and between treatment groups.

Main Results:

• A total of 40 VOCs were identified, with 24 of microbial origin. VOC profiles changed more rapidly in un-inoculated pellets stored at ambient temperature compared to those stored at 5 °C or inoculated with H57.
• PCA revealed significant differences in VOC profiles, primarily driven by nine specific mVOCs in un-inoculated pellets.
• These identified mVOCs are known markers of fungal spoilage in grains, suggesting H57's protective role against specific fungal contaminants.

Conclusions:

• Bacillus amyloliquefaciens strain H57 effectively maintains the odour profile and freshness of concentrated feed pellets.
• H57's ability to inhibit mVOC production offers a protective mechanism against microbial spoilage in stored animal feed.
• The protective effect of H57 can be observed within 3 months of ambient temperature storage, indicating its practical application in feed preservation.