Growth, reproductive performance, muscle and egg composition were investigated in grass carp, Ctenopharyngodon idella (Valenciennnes), fed hydrilla or formulated diets with varying protein levels. Five experimental diets, with varying levels (20%, 25%, 30%,35% and 40%) of crude protein (CP), were used. One of the ¢sh groups was fed hydrilla. Fish (44.1 AE 0.3 cm; 913 AE 9 g) were stocked (20 tank À1 ) in outdoor concrete tanks (20 Â 10 Â 1.5 m) in duplicate, and fed to satiation, twice daily, at 09:00 and 17:00 hours for the experimental duration of 360 days. High (Po0.05) weight gain was recorded in ¢sh fed 30% and 35% CP diets. However, values for gonadosomatic index (GSI), egg diameter, relative fecundity (eggs kg À1 body weight), fertilizability and hatchability (%) were comparable (P40.05) in ¢sh at ! 25% of dietary protein intake. Hydrilla-fed ¢sh exhibited lower (Po0.05) values for the measured parameters. Crude protein content in muscle increased with dietary protein level. Highest (Po0.05) muscle protein was obtained in ¢sh fed 35% CP diet. Muscle fat was comparable (P40.05) among ¢sh receiving formulated diets. Ash content was not signi-¢cantly (P40.05) di¡erent among ¢sh of di¡erent dietary groups. Moisture content in ¢sh fed formulated diets, with the exception of 20% CP diet, did not vary signi¢cantly (P40.05). Eggs of ¢sh fed formulated diets contained higher CP and fat contents than those of hydrilla-fed ¢sh. High (Po0.05) moisture content was noted in the eggs of hydrilla-fed ¢sh. Ctenopharyngodon idella fed formulated diet, with a minimum of 25% CP, showed better reproductive performance than those fed hydrilla.

A 56‐day feeding trial was conducted to evaluate growth, feed utilization and body composition of fingerling rohu, Labeo rohita (4.5 ± 0.2 cm; 2.58 ± 0.04 g), fed five isonitrogenous (350 g kg−1 crude protein) and isoenergetic (15.7 kJ g−1 metabolizable energy) diets in which the main protein contributors were: diet I, fish meal (FM); diet II, soybean meal (SBM); diet III, groundnut meal (GNM); diet IV, equal amounts of SBM, GNM and canola meal (CM); diet V, equal amounts of FM, SBM, GNM and CM. Fish were stocked in triplicate groups of 25 fish held in 70 L flow‐through tanks (water volume 55 L) and fed twice daily (0900 and 1700 hrs) to apparent satiation. Fish fed diet I exhibited the highest (P < 0.05) values for live weight gain and specific growth rate (% per day). Feed conversion and protein efficiency ratio were better (P < 0.05) in fish‐fed diets I and II. Fish‐fed diet II exhibited lower (P < 0.05) fat and ash contents in carcass. Based on these findings, a 70‐day trial (Experiment II) was conducted with six diets fed under the same conditions where FM was incrementally replaced with SBM. Fingerling L. rohita (6.7 ± 0.4 cm; 4.07 ± 0.02 g) were used for the study. Crystalline l‐methionine was added to diets containing more than 250 g kg−1 SBM. This second study showed no significant (P > 0.05) variation in growth, feed utilization and carcass composition for fish fed the different diets. In conclusion, SBM was more effective than GNM or CM, as FM was replaced in feeds for fingerling L. rohita and could completely replace FM when supplemented with methionine and fortified with minerals under the conditions of this study.

No abstract

No abstract

Climate change is an inevitable event that obstructs the output of aquaculture farms and culture-based fisheries in open waters. It poses a serious threat to global food security, altering biodiversity, ecosystems, and global fish output by displacing fish stocks from their natural habitats. When compared to freshwater aquaculture, marine/coastal aquaculture is more affected. To combat the effects of climate change, several mitigation methods and adaptations are being implemented, emphasizing future demands of affordable protein. Selective breeding, species diversification, and aquaculture systems like integrated multi-trophic aquaculture, aquaponics, and recirculating aquaculture system are some of the most widely accepted and adapted solutions. Further research on intervention in seed and feed in terms of quality improvement, bioresource utilization, and technological and genetic improvement is required. Climate change policies from the government are also essential. The present study differs from previous reviews by portraying the various abiotic stress factors contributing to the drastic climate change, encompassing adaptation strategies followed in distinct aquaculture sources such as freshwater, inland saline water, brackish water, coastal waters, and culture-based capture fisheries with its future implications.

No abstract

Growth and body composition of rohu, Labeo rohita (Hamilton), fed compound diet: winter feeding and rearing to marketable size Summary A 122-day growth trial was conducted to observe the impact of polyhouse in winter on growth, conversion efficiencies and body composition of fingerling Labeo rohita (7.9 ± 1.1 cm; 4.60 ± 0.18 g). Fish were stocked (1.5 m )2 ) in polyhouse and outdoor concrete tanks (250 m 2 ) in duplicate and fed a compound diet [35% crude protein (CP)] to apparent satiation twice daily, at 09.00 and 17.00 hours. A natural photoperiod was maintained during the trials. At the end of the trials, polyhouse-reared fish produced significantly (P < 0.01) higher values for weight increment, specific growth rate (SGR %), protein efficiency rate (PER), protein productive value (PPV) and better feed conversion ratio (FCR). Polyhouse-reared fish showed higher (P < 0.01) CP and fat, and lower (P < 0.01) moisture and ash contents in the muscle. In the second part of the study, which also lasted 122 days, polyhouse-reared young L. rohita (21.7 ± 1.3 cm; 127.8 ± 0.69 g) were raised to marketable size in outdoor earthen ponds (500 m 2 ) at a stocking density of 0.37 m )2 to examine the effects of feeding traditional feed mixture and compound diet (30% CP) on growth and body composition of fish. Labeo rohita fed the compound diet showed higher (P < 0.01) values for weight increment, SGR (%), PER and PPV, and better (P < 0.01) FCR than those fed traditional feed. Proximate composition of fish muscle showed higher (P < 0.05) CP and fat, and lower (P < 0.05) moisture and ash contents in fish fed the compound diet. The results suggest that polyhouse may be used successfully to culture L. rohita during winter, and that thereafter the fish may be reared in earthen ponds using the compound diet to obtain better production.

No abstract