ISSUE FOCUS FEED & ADDITIVE MAGAZINE August 2024 45 PEKILO® was in industrial production and widely used as an ingredient in pig and poultry feeds from 1977 to 1991. Research conducted during that time shows that PEKILO® can be effectively used as a protein source in feeds for terrestrial livestock species without any detrimental impacts on growth performance or feed consumption. Currently, the PEKILO® process is being revitalized, with the focus on valorizing and optimizing locally available side-streams such as forestry by-products. The economic evaluation and nutritional composition of PEKILO® make it a promising alternative to marine and soy proteins in aquaculture feeds. In addition to its high protein content (60–65% crude protein), it also contains bioactive compounds, including β-glucans (10–15%) and nucleotides (10%), which are known to have immunomodulating properties. RECENT STUDIES IN FISH Recent feeding studies show encouraging results: in a 9-week feeding trial conducted with Atlantic salmon, it was shown that PEKILO®Aqua can effectively replace 20% of the crude protein content of the diet without adversely affecting growth. Notably, consumption of PEKILO®Aqua was linked to significant improvements in feed conversion ratio and protein efficiency ratio (PER). The apparent digestibility coefficients (ADCs) remained high, around 85%. In trials with shrimp, PEKILO®Aqua could effectively replace all the fish meal protein, resulting in increased body weight, improved growth rate, and no effects on feed conversion ratio or feed intake. Notably, the improved growth rate increased in tandem with the inclusion rate. The ADCs for crude protein and amino acids showed no significant difference, but the ADC of the amino acids showed higher percentage values with higher inclusion rates. Rainbow trout studies conducted by Luke, showed crude protein digestibility of over 88% for PEKILO®Aqua, while digestibility of nucleotides originating from RNA was over 92%. FISH HEALTH In the Atlantic salmon trials, dietary inclusion of PEKILO®Aqua was associated with significant improvement in gut health, visible even with the lowest inclusion rate (5%). The improvements were associated with the high level of β-glucan in PEKILO®Aqua, which was suspected to increase the percentage area of the simple folds occupied by goblet cells, which are responsible for creating a protective mucus layer in the digestive system and thought to be involved in immunoregulation. Dietary inclusion of PEKILO®Aqua generally resulted in significant improvements in mineral retention efficiencies and nitrogen utilization, which increased with the inclusion rate. In the shrimp trial, diets with high levels of PEKILO®Aqua led to higher survival rates, suggesting potential health benefits. CONCLUSION Filamentous fungi offer a promising alternative protein source for aquafeed due to their high protein content and beneficial bioactive components. PEKILO®Aqua, derived from Paecilomyces variotii, emerges as a strong candidate to replace fish meal and soy. Research shows that PEKILO®Aqua promotes fish growth and improves overall fish health. By incorporating PEKILO®Aqua, the aquaculture industry can reduce its reliance on wild-caught marine resources and imported soy while also upcycling local industry by-products. Additionally, PEKILO cultivation requires no farmland and uses significantly less water than soybean production, making it an environmentally sustainable choice. About Heikki Keskitalo Heikki Keskitalo is the Co-founder and Business Development Manager at Enifer. He is a molecular biologist, plumber, guerrilla (Lapland's Border Guard), and firefighter by training. He has 10 years of experience from protein chemistry and fermentation.
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