Lay cycle lengths in the Canadian egg industry are currently 50 to 52 wk (68-70 wk of age). In light of increased productivity in commercial laying hens over the last few decades, the much longer lay cycle lengths already implemented in other countries, extending lay cycle lengths in Canada, should be considered with careful attention to potential environmental, economic, and animal welfare implications. However, there is a lack of information in the public domain that provides robust evidence of performance levels and potential trade-offs to support comprehensive consideration of the desirability of extending lay cycles beyond current Canadian norms. Hence, a systematic literature review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was undertaken. Data collection focused primarily on information related to feed-, flock management-, and hen genetics/physiology-related interventions that were studied in literature to support extension of lay cycles (review objective 1), and compiling and analyzing productivity, egg quality, and animal welfare outcomes reported at 70 wk of age or beyond (review objective 2). Several feed-related interventions such as high-protein diets, and probiotics supplements, and flock management interventions such split-feeding were found to potentially improve productivity, and especially egg quality, outcomes in the late laying phase. More studies with bigger flock sizes and in commercial lay facilities need to be undertaken before any of these interventions can be definitively recommended for commercial egg production. Under objective 2, productivity was found to be at acceptable levels well beyond 70 wk of age. Performance on most egg quality traits and animal welfare indicators were also at acceptable levels past 70 wk of age but increased variability was observed beyond ∼80 wk of age. There were also inconclusive indications on how hens in caged housing and white laying hens fare relative to hens in noncaged housing and brown-type layers during the late laying phase. Economic data were limited but suggested that lay cycle lengths beyond 90 wk might not generated net economic benefits.

The integration of Multi-Objective Optimization (MOO) and Multi-Criteria Decision-Making (MCDM) has gathered significant attention across various scientific research domains to facilitate integrated sustainability assessment. Recently, there has been a growing interest in hybrid approaches that combine MCDM with MOO, aiming to enhance the efficacy of the final decisions. However, a critical gap exists in terms of providing clear methodological guidance, particularly when dealing with data uncertainties. To address this gap, this systematic review is designed to develop a generic decision tree that serves as a practical roadmap for practitioners seeking to perform MOO and MCDM in an integrated fashion, with a specific focus on accounting for uncertainties. The systematic review identified the recent studies that conducted both MOO and MCDM in an integrated way. It is important to note that this review does not aim to identify the superior MOO or MCDM methods, but rather it delves into the strategies for integrating these two common methodologies. The prevalent MOO methods used in the reviewed articles were evolution-based metaheuristic methods. TOPSIS and PROMETHEE II are the prevalent MCDM ranking methods. The integration of MOO and MCDM methods can occur either a priori, a posteriori, or through a combination of both, each offering distinct advantages and drawbacks. The developed decision tree illustrated all three paths and integrated uncertainty considerations in each path. Finally, a real-world case study for the pulse fractionation process in Canada is used as a basis for demonstrating the various pathways presented in the decision tree and their application in identifying the optimized processing pathways for sustainably obtaining pulse protein. This study will help practitioners in different research domains use MOO and MCDM methods in an integrated way to identify the most sustainable and optimized system.

The growing demand for animal products leads to mounting environmental impacts from the livestock sector. In light of the desired transition from linear to circular nutrient flows and an increasing number of formal commitments toward reducing environmental impacts from livestock production, manure valorization using insects (particularly black soldier fly larvae; BSFL) gains increasing importance. Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, this paper identified 75 BSFL production systems utilizing various types of manure as feed substrates. The review highlights considerable differences in system design regarding the different production steps and their specific characteristics. These differences lead to a wide spectrum of rearing performances, which were measured by a suite of indicators, including dry matter reduction (DMR), waste reduction index (WRI), feed conversion efficiency (FCE), bioconversion rate (BCR), and nitrogen reduction. The results further show that, to date, most manure-valorizing BSFL production systems operate at the micro-scale level. However, specific reduction targets for manure-related emissions will likely necessitate large-scale systems at the farm or industrial level, and further research should thus focus on the comprehensive assessment of potential environmental benefits of manure valorization using BSFL.

Consequential Life Cycle Assessment (CLCA) can play an important role in providing insights for decision-makers regarding potential market-mediated resource/environmental consequences stemming from changes in product systems. However, the consistent application of CLCA encounters challenges due to the absence of common guidelines. This systematic review studied different sets of literature to develop a methodological framework for CLCA of plant protein extraction through fractionation, using Canada as an example. Given that economic models are integral components of CLCA, this systematic review offers a comprehensive survey of the economic models employed in 18 CLCA studies, shedding light on their respective strengths and weaknesses. Notably, the study identifies the use of both Computable General Equilibrium and Partial Equilibrium models for enabling the analysis of large-scale and long-term changes. The estimation of land use changes (both direct and indirect) is an integral part and economic models are instrumental in quantifying indirect land use changes. For characterizing the common modelling practices in the agri-food sector, 33 CLCA studies were reviewed to extract information on the decision context, time horizon, identification of marginal/substitutable markets, uncertainty and sensitivity analyses, etc. ‘Increased supply’ and ‘increased demand’ are both found to be important decision contexts. It is a common practice to identify marginal markets based on assumptions, literature, and other sources along with employing economic models for some cases. However, economic models in the agri-food studies were used more often for estimating land use change impacts. To elaborate the case study of plant protein extraction (i.e., pea fractionation), some of the alternative uses of the co-products of pea fractionation processes as a basis for determining probable marginal markets were identified. Building upon these findings, the review culminates in the proposal of a detailed methodological framework for CLCA applied to pea fractionation, incorporating considerations of marginal markets that revolve around utilizing co-products like pea starch and pea fibre. Future research could focus on identifying marginal markets relevant to the Canadian landscape, thereby enhancing the applicability and relevance of CLCA within this region.