Optimizing weaning strategies with formulated feed for redtail botia Yasuhikotakia modesta larvae

This study investigated the effects of weaning time from live feed ( Moina ) to formulated microdiets on the survival, growth, digestive enzyme activities, and nutritional composition of redtail botia Yasuhikotakia modesta larvae. Results showed that early weaning (12–15 days after hatching, DAH) led to sharp declines in survival and reduced growth, likely due to immature digestive capacity and poor nutrient assimilation. In contrast, later weaning (18–24 DAH) maintained high survival rates comparable to continuous live feeding. Digestive enzyme analyses revealed that trypsin, pepsin and amylase activities increased in microdiet-fed groups. In addition, pepsin activity was lower under early weaning compared to later weaning, reflecting delayed gastric development. Lipase activity was not significantly affected. Nutritional composition analyses indicated higher protein content in larvae fed Moina, consistent with its high protein level and accumulation efficiency, whereas microdiet treatments showed higher lipid content. Our results suggest that an appropriate weaning time for redtail botia is around 18 DAH, coinciding with digestive maturation, which is essential for maintaining larval survival and growth.