Alternative and Novel Livestock Feed: Reducing Environmental Impact

Livestock production systems are generally considered to have various negative environmental impacts, including nutrient leaching, and a significant contribution to global warming. In this respect, the reduction of gas or ammonia emissions can be achieved through improved efficiency in the choice of feedstuffs. The use of alternative feeds or additives can contribute to a more energy-efficient ration with lower emissions. Such strategies can contribute to improved animal production and health status. Studies have reported that feed additives such as nitrogen-containing compounds, probiotics, prebiotics, and plant extracts significantly reduce ruminant methane. Moreover, research suggested that fruit pomaces could be a low-cost fibre source in poultry nutrition, and that the inclusion of orange pulp in pigs’ diets can reduce the potential ammonia and methane emissions. To properly evaluate the most adequate reuse strategy it is necessary a specific life cycle assessment for each co-product.
The Food and Agriculture Organization (FAO) stated that livestock farming systems are involved in 14.5% of human-induced greenhouse gas emissions, coming from enteric fermentation. Depending on the production system in question, research shows that animal feed accounts for 55 to 75% of climate change effects. Cultivation and processing, transport and land use change are the main global sources of greenhouse gas emissions in animal feed production. Additionally, enteric methane emissions from ruminants and monogastric animals seem to significantly contribute to agriculture’s environmental footprint. Methane and ammonia emissions also represent a substantial loss of feed energy. The use of alternative feed and additive could improve total diet digestibility and have significantly more potential in increasing animal performance and mitigating emissions. Alternative feedstuff may also offer additional benefits such as modification of lipids in ruminant products (microalgae) and mitigation of methane emissions. However, the feasibility of using alternative feedstuff depends on the feed value of novel ingredients, animal production responses, and feed costs compared to the conventional feeds. The environmental footprint and the economic value of novel feedstuffs in alternative to conventional ones are of great relevance.
The main objective of this Research Topic is to collect worldwide in vitro and in vivo Original Research papers, Systematic Reviews, Reviews, and Brief Research Reports, focusing on using alternative feed in animal nutrition with a transdisciplinary approach, and providing useful results on economic advantages and life cycle assessment analysis.