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Two 45‐day experiments were conducted to substitute the de‐oiled rice bran (DORB) with Khejri pod meal (KPM) and groundnut oilcake (GNOC) with Khejri seed meal (KSM) in the diet of rohu, Labeo rohita. In the first experiment, diets comprised 0, 50, 100 and 150 g KPM kg−1 diet and denoted as CP, KPM5, KPM10 and KPM15, respectively, while in the second experiment, the diets contained 0, 50, 100 and 150 g KSM kg−1 diet and designated as CS, KSM5, KSM10 and KSM15 respectively. We randomly distributed 120 fish (mean weight‐ 5.10 ± 0.05 g) to twelve experimental tank following completely randomised design. Dietary KPM did not influence the growth rates, feed conversion ratio, body indices, body composition and survival (p > 0.05). No differences were observed in digestive, metabolic and stress enzymes activities (p > 0.05). In the second experiment, significantly higher growth performance and feed conversion were found in KSM5 and KSM10 (p < 0.05). However, these were similar in control and KSM15‐fed groups (p > 0.05). Intestinal protease activity (r = 0.65), hepatic alanine aminotransferase (0.94–0.95) and aspartate aminotransferase in muscle (r = 0.93–0.94) were positively correlated with growth indices. Hepatic lactate dehydrogenase and catalase activity were significantly higher in KSM15‐fed group (p < 0.05). Based on the results, 50% substitution of DORB and GNOC with KPM and KSM could be possible in the carp diet respectively. [ABSTRACT FROM AUTHOR]

Copepods of genus Acartia are considered as efficient live feeds for marine fish larviculture. A few reports are already there on production and storage for eggs of few temperate species of Acartia. Present study evaluated the storage potential of eggs of a tropical calanoid copepod, A. tropica. Different conditions examined were higher salinity storage (40–200 ppt) at room temperature, cold storage (4ºC) at different salinities (15–200 ppt), cryoprotectant solutions (methanol, glycerol) and antibiotic solutions (kanamycin, oxytetracycline). Results showed that higher salinity storage (50–200 ppt) could not retain egg viability under cold storage, as well as normal temperature conditions. The eggs exposed to cold storage and lower salinities (15–40 ppt) for 24 h survived with highest egg‐hatching success (EHS, %) recorded at 15 ppt (69.44 ± 8.12). The condition was not efficient to retain egg viability beyond 24 h. The addition of certain cryoprotectants and antibiotics to the storage media significantly improved the survival of A. tropica eggs after 48 h storage. In the cryoprotectant treatments highest EHS after 48 h storage was recorded at 1M Glycerol (41.27 ± 6.34). Amongst the antibiotic treatments highest EHS after 48 and 72 h of storage were recorded at 100 ppm Kanamycin (46.79 ± 10.33, 2.67 ± 0.35) and 50ppm Kanamycin (43.86 ± 12.81, 1.73 ± 0.27), respectively. A drastic reduction in egg viability was recorded after 48 h and the antibiotics and cryoprotectants examined were not efficient to retain egg viability beyond 72 h. Hence the conditions examined in the present study could retain the viability of A. tropica eggs maximum up to 72 h and were not sufficient to induce long term quiescence in A. tropica eggs. [ABSTRACT FROM AUTHOR]

The annual reproductive cycle of picnic seabream, Acanthopagrus berda (Forsskål, 1775), one of the potential aquaculture candidate from estuarine waters of Calicut, Kerala (India) was studied. Based on the morphological and histological studies, the ovotestes of A. berda were classified as active male, active female, inactive male, inactive female, transitional and undifferentiated. Histological observation of transitional gonads showed signs of degeneration in the testicular lobe, proliferation of connective tissue and empty sperm ducts indicating protandrous hermaphroditism in A. berda. Ovary was classified into seven maturity stages (virgin, developing virgin, developing, maturing, mature, running, spent) and testis into five maturity stages (resting, maturing, mature, running, spent). Gonadal development in A. berda indicated resting phase (February–July), pre‐spawning phase (March–August) and spawning phase (August–December). Inactive (24.6%) and active males (21.6%) were observed as dominant in smaller length classes (140–250 mm TL), whereas inactive (18%) and active females (51%) were observed as dominant in larger length classes (251–450 mm TL). Few primary females (28.1%) were observed in smaller (below 250 mm TL) and few primary males (28.5%) were observed in larger length classes (above 250 mm TL). From the present study, it can be concluded that in A. berda, most of the individuals function first as males and then change sex to female, but few continue to function as either male or female throughout their lifespan indicating digynous protandrous hermaphroditism. [ABSTRACT FROM AUTHOR]

Abstract : The morphometric and carcass quality changes associated with the compensatory growth of stunted fish in optimum culture condition differentiate the quality of poststunted fish from normal fish. This study compared carcass quality characteristics data on poststunted and normal milkfish of marketable size reared under pond culture conditions. The cultured fish samples of poststunted and normal milkfish (of average weight 420–500 g) were collected from the brackish water fish farm at ICAR‐Central Institute of Fisheries Education, Kakinada, Andhra Pradesh, India. Fish stunted for 8 months were further reared for a period 8 months (poststunting), whereas normal fish were reared at the optimal condition for 16 months followed by an assessment of carcass quality characteristics such as morphometric, offal, carcass filleting traits and carcass proximate composition. The results showed higher dressed carcass traits such as dressed (85.42%), headless dressed (66.92%) and skinless dressed percentage (65.69%) in poststunted fish than the normal fish. However, the study did not find any significant difference in offal and dressed carcass trait yields. The fillet cutability traits found a higher percentage of meat (64.40%) and lower bone content (14.19%) in poststunted fish. This study recorded higher meat percentage in mid cut followed by fore and hind cuts in both groups of fish. The proximate composition of fillet cuts showed significant differences in moisture, dry matter, protein and fat content between normal and poststunted fish. Further, the study proved that nutrient accretion and deposition vary considerably among body components of fish during the compensatory growth phase. Overall, the results of this study suggested that poststunted fish are more nutritious and yield better fillets concerned with processing efficiency and nutritional quality for consumers than normally reared milkfish. [ABSTRACT FROM AUTHOR]

Impact of osmoregulation on plasma sex steroid levels and gonadal histo-architecture was monitored to elucidate the effects of deviation from habitat salinity on gonadal recrudescence in an active reproductive season of an euryhaline fish Etroplus suratensis (pearlspot). Fish were maintained in three different salinities of 0 ppt Fresh Water ( FW), 15 ppt Brackish Water ( BW) and 30 ppt Sea Water ( SW) for a period of 60 days. Plasma osmolality values were found to be significantly highest in SW-acclimated fish accompanied by highest levels of plasma K⁺ and Cl¯ ions. The progress of gonadal recrudescence was higher in BW followed by FW and SW as evident from the cellular features of gonads and increased level of plasma sex steroids, such as, in case of female and 11-keto Testosterone and Testosterone in case of males. Plasma cortisol levels were comparatively higher in fish of both sexes in SW group. Significantly high levels of cortisol in SW suggest its role in hypo-osmoregulation and associated stress. This study clearly reveals that salinity changes during the active reproductive phase can suppress the steroid-mediated gonad recrudescence maximally under hypo-osmoregulation in an euryhaline fish. [ABSTRACT FROM AUTHOR]