56 JUNE 2017 • WORLD AQUACULTURE • WWW.WAS.ORG eggs were counted. Dead eggs were counted and removed each day to protect healthy eggs from fungal infection. Hatching occurred after 4 days and was completed within 24 hours, when distinct eyes were seen in hatchling fish. Early hatched larvae had a large yolk sac and settled around stones or near corners of the incubation tray. After attaining the free-swimming stage, larvae were transferred to a tank of 2.5 m × 0.4 m × 0.3 m (L × W × D). On 26 March, another two female fish were injected with Ovaprim spawning hormone at 0.5 mg/kg body weight. Four mature males were also kept in the spawning tank. After 26 hours, when females were checked by pressing gently on the stomach, one female released eggs. Milt from two males was used to fertilize eggs. Fertilized eggs were incubated as before, and hatching occurred after 80-88 h. Reproductive parameters (relative fecundity, fertilization rate, hatching rate, and survival rate) were measured to analyze breeding performance. The total number of eggs and egg number per kg body weight were calculated after fertilization. Egg size, mean weight of eggs and mean weight of swim-up fry were measured using an electronic balance. Fertilization rate, hatching rate, incubation period, hatchling survival rate, yolk absorption time, and time of hatchling to fry were also recorded. A fry rearing experiment was conducted for 45 days using commercial feed or a locally prepared feed on hatchery produced fry. Each treatment was replicated three times. Sahar fry of 73-77 mg body weight were stocked at 200/m2 in a hapa and water depth was TABLE 1. Result of sahar brood female maturity tests on different sampling dates from November 2014 to March 2015. Date Number of Number Water overmature of ripe temperature (C) females females 21 November 1 21.2-23.0 24 November 1 19.7-22.8 8 December 2 18.2-21.2 9 December 2 17.5-20.5 4 January 1 15.5-17.2 21 February 1 19.1-21.3 24 February 2 19.4-22.0 27 February 1 20.6-22.8 4 March 2 22.5-26.0 7 March 1 22.2-25.4 9 March 1 1 23.3-25.2 27 March 1 25.3-28.7 TABLE 2. Breeding performance of sahar with and without induced maturation. Variable Natural Induced breeding breeding Date 9 March 27 March Temperature (C) 23.3 -25.2 25.3-28.7 Female body weight (kg) 1.2 1.3 Male body weight (kg) 0.65, 0.80 0.72, 0.87 Total eggs spawned 2585 4738 Eggs per kg body weight 2119 3746 Number of eggs per g eggs 94 103 Fertilization rate (percent) 98 99 Incubation period (hr) 96-104 80-88 Hatching rate (percent) 95 97 Hatchling survival (percent) 81 90 Yolk sac absorption period (d) 6 5 Time to swim-up fry (d) 17 17 TABLE 4. Growth performance of sahar fry fed with different feeds for 40 days (mean±SE). Mean values with same superscript in the same row are not significantly different (p<0.05). Descriptions Feed type Commercial Local Initial weight (mg) 78.7±2.5a 72.4±3.3a Final weight (mg) 267±20a 302±17a SGR (percent/d) 3.03±0.20a 3.56±0.16a DWG (mg/fish/d) 4.71±0.50a 5.74±0.42a Survival (percent) 99.4±0.3a 99.4±0.3a AFCR 1.7±0.1a 1.4±0.1a TABLE 3. Mean ± SD and range of values (in parentheses) for sahar egg diameter, length and weight of larvae and fry from natural and hormone-induced breeding. Parameter Natural breeding Induced breeding Fertilized egg 2.9±0.2 3.1±0.3 diameter (mm) (2.8-3.5) (2.8-3.3) Fertilized egg 12.4±0.8 12.7±0.8 weight (mg) (11.6-13.2) (12.0-13.5) Newly hatched 9.4±1.2 8.9±0.7 larvae length (mm) (8.2-10.6) (8.2-9.6) Newly hatched 13.0±0.5 13.2±0.5 larvae weight (mg) (12.5-13.5) (12.7-13.7) Yolk-sac absorbed 11.5±0.5 11.5±0.5 larvae length (mm) (11-12) (11-12) Yolk-sac absorbed 10.1±1.1 9.9±1.4 larvae weight (mg) (9.0-11.2) (8.5-11.3) Swim-up fry (17 d) 14.6±0.5 13.3±0.5 length (mm) (14.1-15.1) (12.8-13.8) Swim-up fry (17 d) 21.0±1.1 14.0±0.4 weight (mg) (19.1-22.5) (13.5-14.6)
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