Feed efficiency (FE) is one of the most economically and environmentally important target traits for genetic improvement since feed accounts for 50–70% of total production expenses in aquaculture worldwide. In addition to lowering production costs, reducing feed consumption per unit of biomass output also reduces emissions of nitrogen and phosphorus, which is in line with global sustainability goals for food production. The genetic framework of FE traits, molecular dissection of the targeted loci, conventional selective breeding frameworks, genomic selection, emerging biotechnological applications, major implementation challenges, and prospects are all covered in this review, which summarizes current developments in genetic improvement of FE in aquaculture. We incorporate empirical data from important farmed finfish and crustacean species, emphasizing that FE-related traits show measurable genetic variation available for selection, although reported heritability estimates vary substantially among traits, populations, phenotyping methods, and production conditions. Compared to conventional breeding techniques, the integration of high-throughput phenotyping, genomic prediction and multi-omics approaches has expanded opportunities to characterize FE variation and improve selection accuracy. However, most reported candidate loci and genes remain supported by associative rather than causal evidence, and functional validation in aquaculture remains limited. Integrated breeding approaches therefore offer feasible pathways to mitigate major constraints to genetic improvement of FE, although their practical application differs substantially among species and production systems.

Salmonella infection, heavy metal bioaccumulation (lead, cadmium), and carcinogenic polycyclic aromatic hydrocarbons from traditional smoking are serious food safety issues in the Nigerian African catfish value chain. This systematic literature review compiles data from previously published studies, including benzo(a)pyrene levels ranging from 738 to 994 μg/kg and a knowledge practice gap where 84% of processors show awareness of hygiene but only 21% follow safety procedures. Due to inadequate post-harvest practices, fragmented regulation, and reliance on artisanal processing, Nigeria continues to violate international food safety standards despite its leadership in catfish production. This review identifies three major risks: pathogenic contamination in wet markets, PAH formation from unregulated kiln temperatures, and moisture induced fungal growth (>12% moisture) in smoked products. A three-point HACCP approach is proposed: raw material supplier verification, kiln temperature adjustment (70–120°C) to reduce PAHs, and moisture barrier packaging. Socioeconomic constraints, the knowledge practice gap, and regulatory fragmentation remain obstacles. This review introduces a “Tiered HACCP System for Resource Constrained Processors,” where three Critical Control Points are prioritized by risk severity rather than processing sequence: raw material screening, thermal processing with temperature modulation, and moisture barrier packaging. This tiered approach allows resource limited processors to allocate monitoring capacity to the highest risk stages first.

Global demand for animal protein is projected to exceed 30% of agricultural output by 2050, placing unprecedented pressure on feed resources. While conventional feed processing methods improve hygiene and palatability, they can inadvertently reduce nutrient bioavailability and generate anti‑nutritional factors. Microbial fermentation offers a low‑cost, eco‑friendly alternative that addresses these limitations. This narrative review examines feed fermentation technology and the decisive role of microbial strains in enhancing feed quality for livestock and aquaculture. Three primary fermentation platforms are discussed: solid‑state fermentation, submerged fermentation, and two‑stage/hybrid systems, along with critical process parameters including temperature, pH, moisture, aeration, inoculum size, and fermentation time. The selection of microbial strains is identified as the “soul” of fermentation. We review the functional roles of bacterial, yeast, and fungal strains, as well as the synergistic benefits of multi‑strain consortia including bacterial–fungal and yeast–bacterial co‑cultures. The influences of fermented feed on aquaculture are analysed across four domains: feed efficiency (improved feed conversion ratio and protein digestibility), immune function (activation of phagocytic cells and cytokine upregulation), gut health (increased villus height and mucosal barrier integrity), and product quality (enhanced pigmentation and shelf life). We conclude that feed fermentation technology represents a transformative strategy aligning with circular bio‑economy principles, and we identify emerging trends including precision fermentation, CRISPR‑based strain improvement, and integration with insect‑based protein production.