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The present study determined the effect of different polychaete extracts, namely, total soluble fraction (TSF), neutral lipid fraction (NLF) and polar lipid fraction (PLF), in the maturation and sperm quality of male Penaeus indicus. Three levels (0.25, 0.50 and 1.00%) of extracts were included using a 3 × 3 factorial design. Groups fed the basal diet (BD) and fresh-frozen diet served as controls. Extracts in varying doses and control groups did not have a significant effect on broodstock survival (67–87%; p = 0.960), maturation rate (42–68%; p = 0.615), inter-spermatophore period (8–10 days; p = 0.505) or sperm viability (97–100%; p = 0.819). However, sperm counts of broodstock fed BD (11.70 × 106 ±1.05 × 106 per spermatophore) and those fed diets supplemented with polychaete extracts were significantly higher compared to that fed with control fresh diet at 0.73 × 106±.09 × 106 (p = 0.001). Spermatophore crude lipid was highest in groups fed 0.25% TSF and 0.25% PLF of broodstock (p =1.0 x10−6). Inclusion of TSF (0.25–1.00%) significantly increased the spermatophore crude protein content of broodstock compared to those fed with other diets (p = 1.20 × 10−5). These results demonstrate that NLF and TSF extracts are bioactive components of polychaete which when fed to male P. indicus, can stimulate aspects of sperm production. [ABSTRACT FROM AUTHOR]

Polychaete is considered the best maturation diet for penaeids; however, fluctuating supply and quality warrant detailed studies to understand the specific maturation‐promoting factors present in polychaete. Indian white prawn, Penaeus indicus, was fed diets supplemented with different fractions of Marphysa sp. extracts. Fractions, such as the total soluble fraction (TSF), neutral lipid fraction (NLF), and polar lipid fraction (PLF), were incorporated in the maturation diet at 0.25, 0.50, and 1.00% following a 3 × 3 factorial design. One group was fed with basal diet (BD), and another was fed with fresh squid, mussel, and polychaete, serving as the control. After a 30‐day feeding trial, results showed that the inclusion of polychaete extracts in the diet significantly improved P. indicus maturation compared to groups fed BD and control with 40% maturation rates (MR) (p = 3.4 × 10−4). MR was optimum in groups receiving diets supplemented with ≥0.5% TSF (70.00% ± 0.00) and NLF (60.00% ± 5.77). Similar improved MR was achieved in treatments receiving ≥0.25% PLF supplementation (60% ± 0.00). Accordingly, relative expression of ovarian vitellogenin mRNA of broodstock fed under 0.25 and 0.50% PLF group was 4.44 and 3.96 folds higher than BD, respectively (p = 0.003). No significant differences were detected in the broodstock survival, latency period, hepatosomatic, and gonadosomatic indices. Biochemical content analyses showed no significant differences among the nine treatments except for broodstock's higher ovary protein content in the TSF group (p = 0.037). This study highlights PLF as the most potent component of the polychaete extract in promoting gonad maturation in P. indicus maturation supplemented at a 0.25% optimum inclusion level. [ABSTRACT FROM AUTHOR]

Monosex culture was proven to be an effective rearing method for grow-out, but in a closed-cycle hatchery, males and females are usually reared communally in tanks until maturation. This study determined the effect of communal rearing (CR) and separate rearing (SR) on male and female Penaeus indicus broodstock gonad maturation. This study also evaluated the influence of the rearing method on reproductive behavior and mating success. The results showed that CR female broodstock had higher maturation rates at 77.78 ± 5.31% (p = 0.061) and a shorter latency period at 6.71 ± 2.54% than SR females (p = 0.211), but the differences were not statistically significant. Similarly, maturation rates for both male groups were 40.62 ± 3.12% and were not significantly different (p = 1.00). The interspermatophore period (p = 0.044), spermatophore weight (p = 0.878), count (p = 0.780), viability (p = 0.257), and percent abnormality (p = 0.257) did not vary between males. In terms of the effect of rearing method on reproductive behavior, males from the SR group initiated more chase (p = 0.018) and fight with other males (p = 0.022) than CR males did, and the differences were significant. SR males also touched the discarded molt (p = 0.167) and advanced to the probe position (p = 0.525) more times than CR males, but the differences were not significant. The sum of all the reproductive behaviors was also significantly higher in the SR (54.00 ± 1.20) than in the CR (24.20 ± 0.86) groups (p = 0.017). Initial results showed that successful mating in the SR (80%) was higher than that recorded in the CR group (20%). These findings suggest that monosex rearing of male and female P. indicus will not negatively affect gonad maturation and will enable sex-specific nutritional manipulations, which can even possibly promote higher mating success. • Monosex rearing of P. indicus do not have a significant impact on the maturation rate and latency period of male and female broodstock • Sperm quality was not significantly affected by the different rearing methods • Separately reared males initiated more reproductive-related behavior toward a newly-molted female than CR males • Eighty percent (80%) of the total video recordings in the SR group proceeded to successful mating while only 20% was noted for CR group • Monosex rearing will enable sex-specific nutritional interventions and may increase mating success of domesticated P. indicus broodstock [ABSTRACT FROM AUTHOR]