Document Type : Research Paper
Authors
1 MSc student, Department of Animal and Poultry Science, College of Aboureihan, University of Tehran, Pakdasht, Iran
2 Associated professor, Department of Animal and Poultry Science, College of Aboureihan, University of Tehran, Pakdasht, Iran
3 Assistant professor, Department of Animal and Poultry Science, College of Aboureihan, University of Tehran, Pakdasht, Iran
Abstract
Objective: This study aimed to investigate the chemical composition, dry matter and crude protein degradability, and gas production parameters of Lemna minor (duckweed) in ruminant nutrition.
Methods: In the first phase, the chemical composition and mineral content, gas production parameters, and degradability of dry matter and crude protein of Lemna minor (collected from two regions: Rasht and Varamin) as well as alfalfa forage were determined using standard analytical methods. In the second phase, based on the crude protein content of Lemna minor, the fermentative value of gas production was measured for experimental diets consisting of a control group (60% concentrate and 40% alfalfa) and treatments in which alfalfa was replaced with Lemna minor at levels of 25%, 50%, 75%, and 100%.
Results: The crude protein content in whole Lemna minor from Varamin was significantly higher than that of whole Lemna minor from Rasht and alfalfa forage (P<0.05). The neutral detergent fiber (NDF) content of whole Lemna minor from both Rasht and Varamin was higher than that of alfalfa (P<0.05). Crude ash content in whole Lemna minor from Varamin was higher than in the Rasht sample and alfalfa (P<0.05). The concentrations of macro-minerals (calcium, phosphorus, magnesium, and potassium) and micro-minerals (copper, zinc, iron, and manganese) differed between the two Lemna minor samples. Across all incubation times, gas production was significantly greater in alfalfa than in Lemna minor (P<0.05). Similarly, the potential and rate of gas production, metabolizable energy content, and organic matter digestibility were all higher in alfalfa compared with Lemna minor (P<0.05). Methane gas production from Lemna minor was also lower than from alfalfa (P<0.05). The rapidly degradable fraction of dry matter and crude protein in Lemna minor (32.3% and 27.0%, respectively) was significantly higher than that in alfalfa (22.6% and 25.9%, respectively; P<0.05). However, the slowly degradable fraction, the degradation rate constant, and the effective degradability at passage rates of 0.02, 0.04, and 0.06 per hour for both dry matter and crude protein were higher in alfalfa than in Lemna minor from Rasht (P<0.05). Replacing alfalfa with Lemna minor in the experimental diets significantly reduced gas production at various incubation times, particularly at higher replacement levels (P<0.05). Moreover, the gas production potential parameter (b) and metabolizable energy content were highest in the control group without Lemna minor and lowest in the treatment where alfalfa was completely replaced by Lemna minor (P<0.05).
Conclusion: Considering its crude protein content, mineral concentrations, and degradability characteristics, Lemna minor has potential as a valuable feed ingredient in ruminant diets. Nevertheless, further studies, especially under practical farm conditions, are recommended before its widespread application.
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