Effects of probiotic doses on the survival and growth of hatchlings, fry, and advanced fry of Rohu (Labeo rohita Hamilton)

ABSTRACT

Rohu (Labeo rohita) is the most popular fish in South Asia. Its farming is often constrained by shortages of seed due to low survival (20%–30%) during nursing. Hypothesizing that probiotics might help, varying doses of two multistrain commercial probiotics were tested at hatchling (days 8–38), fry (days 38–68), and advanced fry (days 68–98) stages. The first probiotics (P1) consisted of Bacillus subtilis, Pediococcus acidilactici, and yeast (Saccharomyces cerevisiae) and the second probiotics (P2) of Bifidobacterium and Lactobacilli plus yeast (Saccharomyces cerevisiae), microalgae (Spirulina sp.), and phytase. Low, medium, and high doses of P1 (1.0, 2.0, and 3.0 g/kg) and P2 (0.5, 1.0, and 2.0 g/kg) were tested, supplementing the control diet, which consisted of mustard oil cake (40%), rice bran (30%), wheat flour (20%), and fish powder (10%). At the hatchling stage results showed that medium and high doses of P1 increased survival by 14.4% and 16.2% respectively over the control. Similarly, medium and high doses of P2 increased survival by 22.1% and 22.3% respectively compared to the control. Survival of hatchlings and fry increased linearly (P < 0.01) with the increase in the doses of P1. The dose of P2 had a quadratic relationship with the survival based on which dose of 1.5 g and 1.7 g/kg feed was found to maximize the survival of hatchlings (72%) and fry (99%) respectively. Regression analysis also showed that maximum specific growth rate (SGR%/day) of fry could be obtained with the estimated dose of 3.3 g/kg diet for P1 and for 1.5 g/kg diet for P2. Therefore, tested probiotics are beneficial during the nursing of Rohu hatchlings and fry or before the age of 68 days but not for nursing afterwards.

KEYWORDS:

• Probiotics
• Labeo rohita
• hatchlings and fry
• survival and growth

Acknowledgments

The authors acknowledge the contribution of the European Union (EU) through the Asia Link Program, which supported the research carried out at the partner university, i.e., Agriculture and Forestry University (AFU), Chitwan, Nepal.

Disclaimer

The European Commission supported the production of this publication but does not constitute an endorsement of the contents, which reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the European Union through the Asia Link Program (Grant no. TH/Asia-Link/016-141-287). However, it does not constitute an endorsement of the contents, which reflects the views only of the authors, and the European Union cannot be held responsible for any use which may be made of the information contained therein