March is a great month for looking forward to Spring in Europe and some finer weather at last. I will be attending the VIV and Aquatic Asia meeting in Bangkok, Thailand this month and will report further in our next issue. This will be a large event with many exhibitors and our Aquatic Asia will be a venue for scientific and technical exchanges with speakers from academia and the industry. My talk will be focused on fermented corn protein from research associated with the bioethanol industries. DDGS and protein enhanced products are making significant inroads to closing the protein gap in farmed fish and shrimp. There is much more scope and potential to test these sources for many more fish species.

The quest for alternative protein and energy rich ingredients is at the heart of modern fish feed formulations while fishmeal and fish oils are more strategically used nowadays for special considerations in strict carnivorous fry and juvenile diets. There is much more flexibility for the higher volume feeds for the on-growing stages of fish production and reduced fishmeal inclusions.

I have been recently engaged in working with new types of Single Cell organisms’ rich in high quality proteins with excellent amino acid profiles. Single cell proteins (SCPs) have gained increasing attention as an alternative to traditional protein sources for fish farming and shrimp production, such as fishmeal and soybean meal. SCPs are derived from microorganisms, such as yeast and algae, which can be grown on inexpensive and renewable substrate and can provide a more sustainable and cost-effective alternative to traditional protein sources. More recently we have been conducting work on specific bacterial sources from aerobic fermentation of organic biowaste streams.

SCP production methods can be divided into two main categories: solid-state fermentation (SSF) and submerged fermentation (SmF). SSF involves the growth of microorganisms on solid substrates, such as sawdust, straw, or food waste, while SmF involves the growth of microorganisms in liquid culture media. Both methods can produce SCPs in high yields, and the choice between them depends on factors such as the type of substrate available, the desired product, and the desired production scale. In terms of nutritional quality, SCPs are considered to be comparable to traditional protein sources for fish and shrimp feed.

The use of SCPs as a protein source in aquaculture is conservative, but there have been numerous studies demonstrating their potential to replace traditional protein sources in feed formulations. In one study, for example, researchers found that SCPs derived from yeast could effectively replace up to 50 percent of the fishmeal in diets for tilapia and rainbow trout, without negatively affecting growth or feed efficiency (Azevedo et al., 2018). Similarly, a study of shrimp aquaculture in India found that SCPs derived from algae could replace up to 20 percent of soybean meal in feed without negatively affecting shrimp growth or survival (Rao et al., 2017).

Despite the promising results, there are still some challenges that need to be addressed to make SCPs a more widely adopted alternative to traditional protein sources. One major challenge is the cost of SCP production, which is currently higher than that of traditional protein sources. However, as production methods continue to improve and economies of scale are achieved, it is expected that the cost of SCPs will become more competitive. Another challenge is the variability in the quality of SCPs, which can depend on factors such as the type of microorganism used, the substrate, and the production conditions. To address this challenge, it is important to develop standardized methods for SCP production that can ensure consistent quality, uniformity, efficacy, and safety.

In early February, I was delighted to have given a presentation via an online platform to the Fisheries and Aquaculture Symposium held in Lahore, Pakistan through the kind invitation of Dr Noor Khan, Dean, and fish nutrition leader in the University of Veterinary and Animal Sciences, Lahore, and the University of the Punjab. My talk examined the potential to advance the health and robustness of farmed shrimp through diet modulation approaches. I am working closely with Dr Khan’s group as co-supervisor of his students and resulting peer-reviewed scientific papers. Work on snakehead and tilapia has progressed into published papers.

Finally, it is with much sadness that I report the passing of a great friend and academic colleague in the biosciences and fish nutrition world. We lost Dr Rune WaagbØ, (Scientific Program Director/Professor at the Institute of Marine Research/University of Bergen) Bergen, Norway at the end of 2022. Rune was one of the most eminent specialists in our field. I knew Rune very well and he invited me to Norway many times for meetings and to act as first examiner to several of his PhD students. Rune had a long-distinguished career and was highly esteemed for innovative work on salmonids with a focus more recently on fish health and welfare concerning vitamin and mineral nutrition. He was a pioneer in so many ways and was instrumental in validating the important role of histidine in the prevention of cataracts in the Atlantic salmon. His research on vitamin E, antioxidant function and essential fatty acids and metabolism was timely. He also advanced our understanding of effects on bone development and deformities in intensive production of salmon. I met Rune at numerous conferences globally and he loved it when I called him my best Viking friend. He graciously accepted my invitation to him as guest plenary speaker at our Aquaculture session in the British Society for Animal Sciences, 2018 meeting held in Dublin, Ireland. Rune as usual gave a wonderful talk with his deep knowledge and experience. Socially, he was also excellent company with wisdom, wit, and humour. I will very much miss Rune Waagbo but his legacy and place in aquaculture nutrition history is assured. He set the highest standards and example for us all to follow. His passing will be regretted by a large number of fish nutritionists, academics and students who have had the privilege of knowing him.