Rearing Silver Therapon Leiopotherapon plumbeus (Teleostei: Terapontidae) Larvae Using Euryhaline Rotifers as Starter Food
Frolan A. Aya, Vicar Stella N. Nillasca, and Luis Maria B. Garcia
Received: January 20, 2021/ Revised: October 11, 2021/ Accepted: November 29, 2021 (https://doi.org/10.62550/AL20010021)
The silver therapon Leiopotherapon plumbeus is an important but dwindling freshwater food commodity in the Philippine freshwater habitats. The influence of feeding regimes on growth performance and survival of first-feeding silver therapon larvae fed euryhaline rotifers (Brachionus rotundiformis and B. plicatilis) as starter food was examined. Larvae at 2 days post-hatch (DPH) (1.93 ± 0.07 mm; 200 larvae/basin) were initially reared on rotifers for 12 days followed by Artemia nauplii from 14 to 35 DPH as follows: (A) B. rotundiformis from 2-13 DPH; (B) B. rotundiformis from 2-7 DPH and Moina micrura from 8-13 DPH; and (C) B. plicatilis from 2-13 DPH. After 35 days of rearing, mean survival rates were significantly higher in larvae fed B. rotundiformis (69.2%) than those co-fed B. rotundiformis and M. micrura (34.6%) or B. plicatilis alone (26.3%). Higher ingestion rates were observed for B. rotundiformis-fed larvae (1.6 ± 0.5 to 4.4 ± 0.5 ind larvae-1) than larvae fed B. plicatilis (0.0 to 3.2 ± 0.8 ind larvae-1) during the critical initial feeding stage. However, larvae fed B. plicatilis (20.75 ± 0.48 mm) were significantly longer than those fed B. rotundiformis alone (15.62 ± 0.40 mm) or co-fed B. rotundiformis and M. micrura (18.57 ± 0.58 mm). The fastest growth was observed in larvae fed B. plicatilis, with length increment (LI) and specific growth rate (SGR) of 18.8 mm and 6.8% day-1, respectively. Eye diameter, head length, snout length and pre-anal length increased but were not affected when larvae were fed two rotifer species. These results demonstrate that feeding euryhaline rotifer B. rotundiformis from 2 to 13 DPH followed by Artemia is a suitable feeding regime for better survival of silver therapon larvae under laboratory rearing conditions.