Improving weaning strategies for Oscar fish (Astronotus ocellatus) larvae: effects of body weight, survival rate and resistance to environmental stress

Improving weaning strategies for Oscar fish (Astronotus ocellatus) larvae: effects of body weight, survival rate and resistance to environmental stress

The huge attention toward dried food in ornamental fish culture is caused by the difficulty related to live-food preparation. This study investigated the effects of replacement of live feed by commercial diet Tetra-Min on growth, survival rate and resistance to environmental stress in Oscar fish (Astronotus ocellatus) larvae. The experimental setup was completely randomized design comprised of five treatments including, namely T1 (Forty days Artemia nauplii), T2 (Thirty days Artemia then ten days of commercial feed), T3 (Twenty days Artemia then twenty days of commercial feed), T4 (Ten days Artemia then thirty days of commercial feed) and T5 (Forty days commercial feed). All treatments were performed in triplicate. In this study fish larvae were fed 4 times a day and to apparent satiation, by commercial feed and Artemia nauplii. After a 40-day feeding experimental period, all the larvae in each aquarium were sampled for biometry and growth determination. The survival rate was significantly affected by the weaning strategies and decreased by reducing the feeding period of Artemia nauplii. The significantly higher survival rates were observed in T1 (70.9 %), T2 (72.8 %) and T3 (70.5 %) compared to other groups. Besides that, lowest survival rate (42.2 %) was obtained in T5. Also, fish larvae in T1, T2 and T3 treatments showed the highest total length (375.4, 358.2 and 355.5 mg, respectively) and total weight (27.4, 26.8 and 26.5 mm, respectively). The lowest total length (15.34 mm) and total weight (241.2 mg) were recorded in T5. The resistance against challenge tests in T1, T2 and T3 treatments was significantly highest in comparison with T5 (P 0.05). The results of the present study demonstrate that the Oscar fish larvae could consume commercial feed starting from 20th day without any difference in growth with larvae fed on live food.

The huge attention toward dried food in ornamental fish culture is caused by the difficulty related to live-food preparation. This study investigated the effects of replacement of live feed by commercial diet Tetra-Min on growth, survival rate and resistance to environmental stress in Oscar fish (Astronotus ocellatus) larvae. The experimental setup was completely randomized design comprised of five treatments including, namely T1 (Forty days Artemia nauplii), T2 (Thirty days Artemia then ten days of commercial feed), T3 (Twenty days Artemia then twenty days of commercial feed), T4 (Ten days Artemia then thirty days of commercial feed) and T5 (Forty days commercial feed). All treatments were performed in triplicate. In this study fish larvae were fed 4 times a day and to apparent satiation, by commercial feed and Artemia nauplii. After a 40-day feeding experimental period, all the larvae in each aquarium were sampled for biometry and growth determination. The survival rate was significantly affected by the weaning strategies and decreased by reducing the feeding period of Artemia nauplii. The significantly higher survival rates were observed in T1 (70.9 %), T2 (72.8 %) and T3 (70.5 %) compared to other groups. Besides that, lowest survival rate (42.2 %) was obtained in T5. Also, fish larvae in T1, T2 and T3 treatments showed the highest total length (375.4, 358.2 and 355.5 mg, respectively) and total weight (27.4, 26.8 and 26.5 mm, respectively). The lowest total length (15.34 mm) and total weight (241.2 mg) were recorded in T5. The resistance against challenge tests in T1, T2 and T3 treatments was significantly highest in comparison with T5 (P 0.05). The results of the present study demonstrate that the Oscar fish larvae could consume commercial feed starting from 20th day without any difference in growth with larvae fed on live food.