REPRODUCTIVE PERFORMANCE OF DOMESTICATED BROODSTOCK OF SILVER PERCH, Bidyanus bidyanus (MITCHELL 1838) AND THE RELATIONSHIP BETWEEN OIL GLOBULE FRAGMENTATION AND EGG QUALITY

Abstract

The experiments investigated the reproductive performance of the domesticated broodstock of the silver perch and the relationship between various degrees of oil globule fragmentation and egg quality. Six years old of second generation broodstock (n=3) were evaluated based on the fecundity, fertilisation rate, hatching rate, the degree of oil fragmentation of egg, and the quality of embryos and larvae produced. The fragmentation were grouped into three categories: un-fragmented (cat-1), moderately fragmented (cat-2), and highly fragmented (cat-3). The results showed that the broodstock had a relatively high fecundity (132,400 ± 7,22), fertilization rate (94.27 ± 1.28%), and hatching rates (87.94 ± 1.23%). The survival rate of larvae at 12 days post hatching (dph) in cat-1 (71.3 ± 0.9%) was higher than cat-2 (66.7 ± 0.9%) whereas cat-2 was higher than cat-3 (61.3 ± 0.3%). The eggs was dominated by cat-1 (78.11 ± 2.44%) which was significantly higher than cat-2 (21.26 ± 2.45%) and cat-3 ones (0.40 ± 0.21%). The survival rate of embryo at 20 hours post spawning (hps) and hatching rate of cat-1 (95.33 ± 0.00% and 93.33 ± 0.00%) and cat-2 (90.00 ± 0.00% and 85.00 ± 0.00%) were significantly higher than cat-3 (72.33 ± 1.76% and 60.33 ± 0.00%). The total length (TL) of the larvae of cat-1 and cat-2 (8.44 ± 0.21 mm and 8.35 ± 0.23 mm respectively) were significantly higher than larvae of cat-3 (7.09 ± 0.14 mm). No significant difference was found in the larval deformities among any categories. In conclusion, the reproductive performance of six year-old broodstock silver perch showing acceptable performance and egg categorisation based on oil globule fragmentation can be used as a useful tool to indicate eggs quality of silver perch.

Effects of exogenous hormones and broodstock age on the spawning response of captive silver therapon Leiopotherapon plumbeus

“…Fertilization and hatching rates decrease in an agedependent manner, wherein younger silver therapon broodstock aged 1 + , 2 + and 3 + years, showed higher fertilization and hatching rates than 4 + -year old females. Other studies have reported higher fertilization rates in younger females of tilapia Oreochromis niloticus (Tsadik Getinet, 2008;Valentin et al, 2015) and gilthead seabream Spaurus aurata (Jerez et al, 2012) whereas the opposite was observed in silver perch B. bidyanus (Sulaeman & Fotedar, 2017). Similar to the results in the present study, Mordenti et al, (2003) found that 5 + to 8 + -year old koi carp C. carpio broodstock had higher hatching rates than 9 + -year old class.…”

“…In addition, Sulaeman & Fotedar (2017) observed that 6-year old silver perch B. bidyanus captive broodstock had still good quality eggs similar to that of 3-year old broodstock. However, Mordenti et al, (2003) found no relationship between fecundity and age of koi carp Cyprinus carpio broodstock ranging from 5 + to 9 + years old.…”

“…Similar to the results in the present study, Mordenti et al, (2003) found that 5 + to 8 + -year old koi carp C. carpio broodstock had higher hatching rates than 9 + -year old class. Hence, it appears that the effect of broodstock age on fertilization and hatching rates is therefore species-specific (Jerez et al, 2012), which can be attributed to nutrition and the level of domestication (Sulaeman & Fotedar, 2017), the latter defined as the degree of human control of reproduction of farmed fish species in captivity without wild inputs (Teletchea & Fontaine, 2014). In the present study, larval production in domesticated silver therapon broodstock is independent of age, which is likely be due to higher fecundity and lower rates of fertilization and hatching.…”