Lupin as a protein supplement for growing lambs

Area of Science:

• Animal Science
• Agricultural Science
• Nutritional Science

Background:

• Soybean meal (SBM) is a common protein supplement for livestock.
• Lupins (Lupinus albus) are a potential alternative protein source.
• Processing methods like roasting can alter nutrient availability.

Purpose of the Study:

• To investigate the effects of roasting on lupin nitrogen (N) availability.
• To evaluate the efficacy of roasted lupins as a protein supplement for growing lambs.
• To compare roasted lupins with soybean meal (SBM) in lamb diets.

Main Methods:

• Whole and dehulled lupins were roasted at various temperatures (130-175°C) and durations.
• In situ rumen N disappearance was measured.
• Lambs were fed diets containing SBM, raw lupins, or roasted lupins.
• Nitrogen retention, growth rate, and feed efficiency in lambs were assessed.

Main Results:

• Roasting significantly decreased in situ N disappearance in lupins.
• Moderate heat roasting reduced N disappearance from 83% (raw) to 45%.
• Lambs fed roasted lupins showed similar growth and feed efficiency compared to those fed SBM or raw lupins.
• Nitrogen retention was comparable between lambs fed raw lupins and SBM.

Conclusions:

• Roasting reduces ruminal N availability from lupins but does not negatively impact lamb growth performance.
• Lupins, whether raw or roasted, can serve as a viable alternative to SBM as the sole protein supplement for growing lambs.
• Further research into optimal roasting conditions may enhance lupin utilization in animal feed.