Diet Effects on Growth, Mortality, RNA: DNA Ratio and Gene Expression of Zebrafish Danio rerio

Abstract

This study evaluated the effects of different combination of commercial and natural diets (T1: egg yolk, T2: egg yolk+ Artemia, T3: Horlicks, T4: Horlicks+ Artemia, T5: TetraBits, T6: TetraBits+ Artemia, T7: NovoTom, T8: NovoTom+ Artemia) on growth, mortality, RNA: DNA ratio and gene expression of zebrafish for a period of 45 days. Significantly highest length (2.75±0.04 cm) and weight (0.25±0.10 g) gain were recorded in T2 treatment. Lowest length gain (2.00±0.08 cm) and weight gain (0.14±0.12 g) were calculated in T3. Significant highest mortality (65.00±8.66%) was observed in treatment T7 followed by T5 and T8 and significant lowest mortality (20.00±7.64%) was recorded in T2. By molecular analysis, Highest RNA: DNA ratio was found (1.01) in T5 followed by T4 (0.95) and lowest was found in T1 (0.77). Interestingly, a similar result was observed for gh1 (Growth hormone 1) gene expression. Highest gene expression was found in T5 followed by T4 and lowest in T2. Significant down regulation was observed in T2 for gh1 gene. Finally, the study would suggest that zebrafish can be fed with egg yolk+Artemia for better growth performance. The findings could provide a significant contribution to the field of global zebrafish as well as aquaculture research.

Toxic Effects of Arsenic in Commercially Important Fish Rohu Carp, Labeo rohita of Bangladesh

“…The analysis of the RNA:DNA ratio has been widely used as an indicator for the measurement of the condition and growth of larval and adult fish, macroinvertebrates, phytoplankton and zooplankton [36,[49][50][51][52][53][54][55]. This method is based on the conception that the quantity of DNA is almost constant in the individual cell but the concentration of RNA is increased based on the synthesis of proteins [56,57].…”

“…Fish were acclimatized in a 35 L capacity tank (12 inch × 15 inch × 24 inch) for a period of one week. Acclimatization was performed according to a previous study, with a few modifications [36]. During acclimatization, fish were fed twice daily with floating carp feed (SMS Feeds Limited, Gazipur, Bangladesh) and fifty percent of water in the culture tank was exchanged daily to keep the water free of fish excreta and other wastes.…”

“…Before measurement, fish were anaesthetized using 2-phenoxy ethanol anesthetic at the rate of 4 µL per 50 mL of culture water. Weight gain (a), length gain (b), condition factor (c) and mortality rate (d) of fish were calculated using the following formulas [36]:…”

“…The determination of the RNA:DNA ratio was performed according to [36] Rabbane et al (2020), with minor modification. For the extraction of DNA and RNA from the target tissue (gill and muscle), the Wizard ® Genomic DNA Purification Kit (Promega, Madison, WI, USA) was used.…”