As the global population continues to grow at an unprecedented pace, the demand for sustainable food sources is rising sharply. Fish, in particular, serve as a critical source of high-quality protein for millions of people worldwide. With over half of the fish consumed globally now coming from aquaculture rather than wild fisheries, the sustainability and efficiency of fish farming have become increasingly important. One of the key challenges in aquaculture is the reliance on fishmeal, a feed ingredient derived from wild-caught fish, which has become more expensive and less readily available in recent years. This has created an urgent need for alternative, high-protein feed sources that can support the continued growth of the aquaculture industry. Insects, particularly silkworm pupae, are emerging as a promising solution.
Silkworm pupae, a byproduct of the global silk industry, are rich in protein and other essential nutrients. During silk production, silkworms spin cocoons of fine silk fibers and subsequently pupate inside these cocoons. After the silk is harvested, the pupae are often discarded as waste. According to Dr. John P. Roche, for every kilogram of silk produced, approximately 1.5 to 2 kilograms of pupae are generated. Considering that the global silk industry produces roughly 90,000 metric tons of silk annually, this translates into nearly 200,000 metric tons of silkworm pupae being available each year. With a protein content ranging between 50% and 70%, these pupae represent an abundant and cost-effective source of animal protein suitable for inclusion in aquafeeds.
In a recent study conducted by researchers at the University of the Punjab, Lahore Government College University, and the University of Education in Pakistan, Tauqeer Hussain, Hafiz Muhammad Tahir, and their colleagues investigated the potential of using silkworm pupae powder as a replacement for fishmeal in the diet of Nile tilapia (Oreochromis niloticus). Their findings were published in the March issue of the Journal of Economic Entomology. The study focused on a commonly farmed, genetically improved strain of Nile tilapia known as GIFT (Genetically Improved Farmed Tilapia), which is widely cultivated in aquaculture systems around the world.
The researchers designed an experiment to assess the impact of silkworm pupae powder on fish growth, survival, feed efficiency, and blood health. Initially, tilapia juveniles were obtained from a local hatchery and acclimated in 1,000-liter tanks for two weeks, during which they were fed standard fishmeal-based diets once daily. During the experimental period, fish were fed twice daily. The study included a control group receiving a conventional feed mixture consisting of fishmeal, soybean meal, corn gluten meal, and other nutrients. Three experimental groups were created, where 10%, 20%, or 40% of the fishmeal was replaced with silkworm pupae powder.
The results were highly encouraging. Fish fed diets containing silkworm pupae exhibited significantly higher weight gain and average daily growth rates compared to the control group. Feed conversion efficiency was also improved, indicating that fish were able to convert their feed into body mass more effectively when silkworm pupae were included in their diets. Importantly, there were no significant differences in survival rates between the control and experimental groups, suggesting that replacing fishmeal with pupae did not negatively affect the overall health or viability of the fish.
These findings align with previous research demonstrating that silkworm pupae powder can enhance growth in various species of farmed fish, including rohu (Labeo rohita), largemouth bass (Micropterus salmoides), and African catfish (Clarias gariepinus). The inclusion of pupae in aquafeed appears to support better growth performance across multiple species, making it a versatile option for aquaculture operations seeking alternative protein sources.
In addition to growth metrics, the research team evaluated the effects of silkworm pupae on several blood parameters, which are important indicators of fish health. Fish fed diets with silkworm pupae showed significant increases in hemoglobin levels, red blood cell count, white blood cell count, and hematocrit values compared to the control group. Moreover, fish in the 20% and 40% pupae inclusion groups exhibited significantly higher mean corpuscular volume, although mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration remained comparable to the control. These improvements in blood health suggest that pupae not only serve as a nutrient-rich feed source but may also enhance the immune function and overall physiological condition of farmed fish, including cardiovascular health.
The use of silkworm pupae in aquaculture feed offers multiple advantages. Beyond providing an affordable and protein-rich alternative to fishmeal, incorporating pupae into diets could help mitigate common challenges in aquaculture, such as disease outbreaks. Fish diseases are a major source of economic loss in aquaculture systems, often necessitating the use of antibiotics or other interventions. By improving blood parameters and supporting immune function, silkworm pupae may help reduce the incidence of disease and potentially lower the reliance on antibiotics, addressing both economic and environmental concerns.
Globally, insects have long been recognized for their high protein content, rapid reproduction rates, and cost-effectiveness. Silkworm pupae, in particular, are widely available as a byproduct of the silk industry, making them a sustainable resource for aquaculture feed. The study conducted by Hussain, Tahir, and colleagues underscores the potential of integrating insect-based protein sources into aquafeeds as part of a broader strategy to meet the growing demand for fish protein in a sustainable and economically viable manner.
Future research in this area could explore optimal inclusion rates for different fish species and life stages, as well as investigate the long-term effects of silkworm pupae on fish health, reproduction, and product quality. Furthermore, comparative studies examining the cost-benefit analysis of pupae-based feed versus traditional fishmeal could provide valuable insights for aquaculture producers considering a transition to insect-based feeds. With the global aquaculture industry projected to continue expanding rapidly, silkworm pupae offer a promising avenue to enhance the sustainability, efficiency, and profitability of fish farming operations worldwide.
In conclusion, silkworm pupae represent a highly promising, protein-rich, and cost-effective alternative to conventional fishmeal in aquaculture. Their use has been shown to support improved growth performance, feed efficiency, and blood health in Nile tilapia and other farmed fish species. By leveraging the abundant byproducts of the silk industry, aquaculture producers can gain access to an affordable and sustainable feed source that contributes to both economic and environmental goals. As research continues and aquaculture practices evolve, silkworm pupae and other insect-derived proteins are poised to play a pivotal role in the future of sustainable fish production, helping to provide high-quality protein for a growing global population.