Effect of two maturation diet combinations on reproductive performance of domesticated Penaeus monodon

Abstract

The reproductive performance of tank-reared, 2nd generation domesticated Penaeus monodon was compared when fed on two experimental maturation diet combinations; a control diet (CD) containing a treatment portion of 32.5% squid ( Photololigo sp.) and 32.5% bivalves ( Plebidonax sp.); and a shrimp-supplemented diet (SSD) containing a treatment portion of 21.6% squid ( Photololigo sp.), 21.6% bivalves ( Plebidonax sp.) and 21.6% shrimp (sexually mature Penaeus sp. and Metapenaeus sp.). The remaining portion of both diets consisted of 5% polychaetes and 30% commercial shrimp pellets. Broodstock were fed on the diets from approximately 10 months of age until commencement of reproductive assessment at 11 months, and until completion of the assessment when females had completed two moult periods post-ablation. No significant difference in growth, survival, ovarian maturation, spawning and egg production was found between diet treatments ( P > 0.05). However, the percentage of spawnings that hatched (mean ± standard error) (CD 77.5 ± 6.7%; SSD 41.2 ± 8.6%) ( P < 0.01), egg fertility rates per spawning (CD 60.2 ± 6.1%; SSD 34.4 ± 8.4%) ( P < 0.05), hatch rates per spawning (including both unhatched and hatched spawnings) (CD 23.3 ± 4.2%; SSD 5.2 ± 1.7%) ( P < 0.01) and nauplii per spawning (× 10 3) (CD 41 ± 9; SSD 6 ± 2) ( P < 0.01) were significantly lower for broodstock fed the SSD than the CD. No difference in spermatophore weight or sperm quantity was found between diet treatments ( P > 0.05). These results indicated that partial replacement of squid and bivalves with sexually mature shrimp in the maturation diet of tank-domesticated P. monodon had a negative effect on egg fertility and hatching. Furthermore, these results highlight the large effect that the final maturation diet can have on reproductive output of domesticated P. monodon broodstock.