Fish oils, misconceptions and the environment

Insect meal in aquafeeds: A sustainable path to enhanced mucosal immunity in fish

The mucosal surfaces of fish, including their intestines, gills, and skin, are constantly exposed to various environmental threats, such as water quality fluctuations, pollutants, and pathogens. However, various cells and microbiota closely associated with these surfaces work in tandem to create a functional protective barrier against these conditions. Recent research has shown that incorporating specific feed ingredients into fish diets can significantly boost their mucosal and general immune response. Among the various ingredients being investigated, insect meal has emerged as one of the most promising options, owing to its high protein content and immunomodulatory properties. By positively influencing the structure and function of mucosal surfaces, insect meal (IM) has the potential to enhance the overall immune status of fish. This review provides a comprehensive overview of the potential benefits of incorporating IM into aquafeed as a feed ingredient for augmenting the mucosal immune response of fish.

The judicious use of finite marine resources can sustain Atlantic salmon (salmo salar) aquaculture to 2100 and beyond

The production of farmed Atlantic salmon (Salmo salar) is currently linked to finite marine resources, particularly fish oil (FO) and fish meal (FM). Understanding this relationship in a quantitative manner is imperative if this critical balance is to be maintained within sustainable limits as the industry grows. Here we project the potential production and associated growth of the Atlantic salmon aquaculture industry on the basis of a variety of FO and FM utilization scenarios in aquafeed. Reducing FO and FM dietary inclusion to 3% each could permit production growth of 2% per year until the turn of the century (2097 and beyond 2100, respectively), independent of a host of alternatives now being utilized-with three portions of salmon per week providing almost all the recommended weekly long-chain omega-3 fatty acids for human intake. The Atlantic salmon industry's positive annual growth can continue in an era of finite marine resource availability-without the need for additional finite marine resource inputs.

Calanus oil in the treatment of obesity-related low-grade inflammation, insulin resistance, and atherosclerosis

Calanus oil (COil) is a natural product extracted from marine zooplankton Calanus finmarchicus found in the North Atlantic Ocean. This oil is rich in wax esters of polyunsaturated fatty acids (PUFAs) and has been projected as the best alternative to fish oil because its production cannot keep pace with the demands from the growing markets. The COil is the only commercially available marine source of wax esters, whereas classic ω-3 PUFAs comes from triglycerides, ethyl esters, and phospholipids. It has, in recent decades, been seen that there is an unprecedented rise in the use of PUFA-rich oil in the aquaculture industry. A simultaneous rise in the demand of PUFAs is also observed in the health care industry, where PUFAs are suggested preventing various disorders related to lifestyles such as obesity, diabetes mellitus, chronic low-grade inflammation, atherosclerosis, and brain and cardiovascular disorders (CVDs). In this review, we will explore the metabolic aspects related to the use of COil as an antioxidant, anticholesterinemic, and anti-inflammatory dietary source and its impact on the prevention and therapy of obesity-related metabolic disorders.

A six-months study on Black Soldier Fly (Hermetia illucens) based diets in zebrafish

Intensive fish farming relies on the use of feeds based on fish meal and oil as optimal ingredients; however, further development of the aquaculture sector needs new, nutritious and sustainable ingredients. According to the concept of circular economy, insects represent good candidates as aquafeed ingredients since they can be cultured through environmental-friendly, cost-effective farming processes, on by-products/wastes, and many studies have recently been published about their inclusion in fish feed. However, information about the physiological effects of insect-based diets over the whole life cycle of fish is presently missing. At this regard, the present study investigated, for the first time, the effects of Black Soldier Fly based diets (25 and 50% fish meal substitution) administration for a six months period in zebrafish (Danio rerio), from larvae to adults. A multidisciplinary approach, including biometric, biochemical, histological, spectroscopic and molecular analyses was applied. Aside a general reduction in fish growth and lipid steatosis, six-months feeding on Black Soldier Fly based diets did not show major negative effects on zebrafish. Gut histological analysis on intestine samples did not show signs of inflammation and both stress markers and immune response markers did not show significant differences among the experimental groups.