There is an increased interest in animal products from more sustainable farming practices, which may include using local breeds. In addition, maintaining biodiversity is important, and naturally, indigenous breeds of chickens are well adapted to the local environmental conditions. In the current study, 286 eggs from 4 Portuguese breeds of chickens (Branca, Amarela, Pedrês Portuguesa, and Preta Lusitânica) and from a commercial hybrid laying hen were used. Chemical and physical characteristics of the eggs and the egg components such as weights, Haugh units, yolk color, albumen protein content, yolk fatty acid content, and mineral content in the albumen and yolk were analyzed. The Branca breed produced eggs with a lighter brown shell color and lower Haugh unit values than the remaining native breeds (P < 0.05). The commercial hens produced eggs that were found to be more rounded shape than the ideal and with a darker colored shell and yolk than eggs from the 4 local breeds. In addition, the commercial hens also produced heavier eggs but with lower Haugh units than the Amarela, Pedrês Portuguesa, and Preta Lusitânica breeds (P < 0.05). The range of saturated fatty acids, monounsaturated fatty acids, and total polyunsaturated fatty acids between eggs from the 4 breeds was small and not significantly different. No differences were found in the percentage of albumen protein between breeds. Albumen and yolk ash content was not different between breeds. The overall analysis indicated that eggs from these native genotypes match the quality of a commercial product in many characteristics. In markets where eggs from local breeds are available, consumers are purchasing a high-quality product while aiding in the expansion of local genetic resources and investing in local farmers.

Key priorities in biochar research for future guidance of sustainable policy development have been identified by expert assessment within the COST Action TD1107. The current level of scientific understanding (LOSU) regarding the consequences of biochar application to soil were explored. Five broad thematic areas of biochar research were addressed: soil biodiversity and ecotoxicology, soil organic matter and greenhouse gas (GHG) emissions, soil physical properties, nutrient cycles and crop production, and soil remediation. The highest future research priorities regarding biochar’s effects in soils were: functional redundancy within soil microbial communities, bioavailability of biochar’s contaminants to soil biota, soil organic matter stability, GHG emissions, soil formation, soil hydrology, nutrient cycling due to microbial priming as well as altered rhizosphere ecology, and soil ph buffering capacity. Methodological and other constraints to achieve the required LOSU are discussed and options for efficient progress of biochar research and sustainable application to soil are presented.

Livestock production is important for food security, nutrition, and landscape maintenance, but it is associated with several environmental impacts. To assess the risk and benefits arising from livestock production, transparent and robust indicators are required, such as those offered by life cycle assessment. A central question in such approaches is how environmental burden is allocated to livestock products and to manure that is re-used for agricultural production. To incentivize sustainable use of manure, it should be considered as a co-product as long as it is not disposed of, or wasted, or applied in excess of crop nutrient needs, in which case it should be treated as a waste. This paper proposes a theoretical approach to define nutrient requirements based on nutrient response curves to economic and physical optima and a pragmatic approach based on crop nutrient yield adjusted for nutrient losses to atmosphere and water. Allocation of environmental burden to manure and other livestock products is then based on the nutrient value from manure for crop production using the price of fertilizer nutrients. We illustrate and discuss the proposed method with two case studies.