Optimizing early weaning protocols for Burbot larvae

Objective This study aimed to minimize live prey usage and duration in Burbot Lota lota larval culture. Specifically, two trials were conducted to assess the viability of EZ Artemia (liquid Artemia replacement) and Gemma microparticulate diets as alternatives to traditional live feeds, investigating their impact on larval Burbot's growth and survival. Methods In trial 1, five treatments were evaluated: the control group received rotifers (Brachionus plicatilis) and Artemia spp. from 11 to 50 days posthatch (dph). Treatment (Trt) 1 had live feeds from 11 to 78 dph; Trt 2 received only microparticulate diets; Trt 3 was fed rotifers at 11–22 dph and Gemma microparticulate diets at 21–50 dph; and Trt 4 received rotifers at 11–20 dph, then co‐feeding of Artemia spp. and EZ Artemia at 21–32 dph, followed by EZ Artemia at 33–40 dph. In trial 2, five feeding treatments were assessed: the control group was the same as in trial 1; Trt 1 received rotifers at 11–25 dph and EZ Artemia at 20–50 dph; Trt 2 had Artemia spp. from 11 to 30 dph and EZ Artemia at 25–50 dph; Trt 3 received only EZ Artemia; Trt 4 had Artemia spp. at 11–21 dph, followed by co‐feeding of Artemia spp. and Gemma Wean at 22–32 dph and exclusive feeding of Gemma Wean from 33 to 78 dph. Result In trial 1, it was found that the utilization of EZ Artemia reduced the live feeding period by 17 days; however, both survival and growth were notably lower compared to the control. In trial 2, survival rates varied from 0% to 30.94%, with Trt 1, Trt 2, and Trt 4 demonstrating a reduction in the live feeding period by 17–24 days. Survival rates for the Trt 1 and Trt 2 groups did not exhibit a significant difference from the control group. Conclusion These studies collectively show that eliminating rotifers or Artemia spp. during Burbot larval culture can be accomplished with minimal adverse effects on both survival and growth. Impact statement The production of traditional live feeds (rotifers and Artemia spp.) entails significant expenses and labor. Early weaning of Burbot larvae onto non‐live foods can reduce infrastructure costs, offering flexibility in feeding practices. This study showcases the effectiveness of prepared feeds including (EZ Artemia and Gemma microparticulate diets) in diminishing reliance on live feeds, presenting them as viable alternatives to rotifers or Artemia spp. in Burbot larval production. This approach enhances the economic viability of commercial hatchery operations for producers i