Comparison of Nannochloropsis oculata Productions Cultivated in Two Different Systems: Outdoor Red Tilapia (Oreochromis sp.) Culture Tank and Indoor Pure Culture

Production of Nannochloropsis oculata or a marine eukaryotic unicellular phytoplankton was the focus of this study. The cultivation of outdoor red tilapia (Oreochromis sp.) in the tank and indoor was compared in producing phytoplankton. Initial density of N. oculata for both culture systems was 0.5 × 106 cell/ml. Findings showed the highest density of N. oculata was attained from tilapia culture system at 9.6x106 cell/ml harvested at day 7 while in pure culture system was 8.5 x106 cell/ml harvested at day 4. Contamination was dominated by protozoa (Gymnodinium sp.), range of 4.80-36.67 × 103 individual cells/ml and 0.00- 41.10 × 103 individual cell/ml at both tilapia culture and pure culture systems respectively. Levels of ammonium, nitrite and nitrate in tilapia culture systems had significantly lower (P 0.05) for vibrio green colonies in both systems. This study concluded Tilapia culture system is as effective as pure culture system to produce N. oculata based on production and quality

Growth performance and gonad maturation of amur catfish, silurus asotus in captivity

This study was aimed to determine the growth performance and gonad maturation of Amur catfish, Silurus asotus reared in captivity. A total of 600 juvenile Amur catfish were reared in a 20-tonne aerated fibreglass tank for 3 months. The changes to body weight (mean ± SD) of Amur catfish at day 14 was 22.59 ± 3.59 g and attained a final average body weight of 110.95 ± 19.72 g. The average body weight gains (%) were 213.50% and gradually decreased to 109.95%. The specific growth rate recorded at 14-day intervals was 5.42%/day and fluctuated to 3.32%/day, 0.39%/day, 0.51%/day, with the corresponding measurements of 15.36 ± 1.07 cm and increments to 24.22 ± 1.34 cm. The final total length the fishes attained was an average of 25.58 ± 1.95 cm. The total length gain recorded was 124.61% and followed by 109.95%. The survival of Amur catfish within the three months was 29.17%. Length-weight relationship of the Amur catfish showed a strong correlation at log W =-2.6797 + 2.3102 log L and the value of the regression coefficient (b) equalled to 2.3102. Three stages of the oocyte (PO = primary oocyte, PVO = previtellogenic oocyte and VO = vitellogenic oocyte) determined histologically indicated that all-female gonad samples were in the developing stage. Matured gonad and spermatozoa were also observed in males. This study concludes that Amur catfish attained good growth performance and fast gonad maturation in captivity and can be a suitable species for aquaculture

Effects of long jack, Eurycoma longifolia on sperm quality and quantity of African catfish, Clarias gariepinus

The experiment attempts to study the effects of long jack, Eurycoma longifolia through the sperm quality and quantity of African catfish, Clarias gariepinus. Mostly farmers are using hormone to induce the reproduction in these fishes especially C. gariepinus. For expanding demand in C. gariepinus, there was expanded exertion in the improvement of method for production of fish in hatchery. Thus, this study was an alternative to improve the production of C. gariepinus. In the present study, two diets with crude protein of 40 % were formulated with different supplementation levels of E. longifolia powder; with no supplementation of E. longifolia (LJ0) and the supplementation of 5 % E. longifolia (LJ5). Eight males of C. gariepinus were randomly distributed into two fibre tanks (2×2×1.5 m) with four fish per tank. The tank contained green water (pH≈ 7.2, dissolved oxygen≈ 5.3 mg/L, temperature≈ 27.20°C). C. gariepinus were fed at 3% of body weight twice a day for a period of 30 days.The diet in LJ5 had significantly higher in sperm counts (12085.33±286.71x104 sperm/ml), milt volume (0.38±0.04 ml) and motility duration (24.11±0.96sec). While the result for diet in LJ0 in sperm count, milt volume and motility duration were 10014.67±273.76x104sperm/mL, 0.21±0.06 ml and 12.67±0.58sec.However, significant differences were not observed in the body weight gained, total length, specific growth rate and feed conversion ratio (FCR) among the two treatments. Besides, the results showed that E. longifolia possess promising pro-fertility which can be exploited in fish seeds production and 50 g/kg of E. longifolia based diet could give satisfactory and efficient result on the sperm quality and quantity of C. gariepinus

Growth Performance and Gonad Maturation of Amur Catfish, Silurus Asotus In Captivity

This study was aimed to determine the growth performance and gonad maturation of Amur catfish, Silurus asotus reared in captivity. A total of 600 juvenile Amur catfish were reared in a 20-tonne aerated fiberglass tank for 3 months. The changes to body weight (mean ± SD) of Amur catfish at day 14 was 22.59 ± 3.59 g and attained a final average body weight of 110.95± 19.72 g. The average body weight gains (%) were 213.50% and gradually decreased to 109.95%. The specific growth rate recorded at 14-day intervals was 5.42%/day and fluctuated to 3.32%/day, 0.39%/day, 0.51%/day, with the corresponding measurements of 15.36 ± 1.07 cm and increments to 24.22 ± 1.34 cm. The final total length the fishes attained was an average of 25.58 ± 1.95 cm. The total length gain recorded was 124.61% and followed by 109.95%. The survival of Amur catfish within the three months was 29.17%. Length-weight relationship of the Amur catfish showed a strong correlation at log W = -2.6797 + 2.3102 log L and the value of the regression coefficient (b) equaled to 2.3102. Three stages of the oocyte (PO = primary oocyte, PVO = previtellogenic oocyte and VO = vitellogenin oocyte) determined histologically indicated that all-female gonad samples were in the developing stage. Matured gonad and spermatozoa were also observed in males. This study concludes that Amur catfish attained good growth performance and fast gonad maturation in captivity and can be a suitable species for aquaculture

Supplementation of duckweed diet and citric acid on growth performance, feed utilization, digestibility and phosphorus utilization of TGGG hybrid grouper (Epinephelus fuscoguttatus x Epinephelus lanceolatus) juvenile

A feeding trial was conducted in juvenile TGGG hybrid grouper to investigate the growth performance, feed utilization, and digestibility after citric acid supplementation in a diet that was partially composed of duckweed. Five isoproteic and isolipidic diets (50% protein, 16% lipid levels) were formulated using Lemna minor and Spirodela polyrrhiza at 5% of fishmeal protein replacement level with or without 3% of citric acid supplementation. A diet without duckweed and citric acid was used as the control diet. Triplicate groups of fish (10.30±0.05 g) were randomly distributed in tanks with a flow through system at a stocking density of 20 fish per tank. The fish were fed twice daily with each experimental diet until apparent satiation for 10 weeks. As a result, the fish fed a diet with duckweed S. polyrrhiza and citric acid (DSC) achieved significantly higher growth, body weight gain (BWG) and specific growth rate (SGR) compared to the control group (P<0.05); however, it was not significantly different with other treatments (P>0.05). The growth, BWG and SGR in fish fed duckweed diets only (L. minor and S. polyrrhiza) were almost similar with the control without significant differences (P>0.05). Similarly in feed utilization, fish fed the DSC diet had a better feed conversion ratio, protein efficiency ratio, and net protein utilization without significant differences (P>0.05) compared to the control. The apparent digestibility coefficient for crude protein and crude lipid, and phosphorus absorption of DSC and the diet with duckweed L. minor and citric acid were comparable to the control without any significant differences (P>0.05). Survival was not affected by the experimental diets. This study showed that TGGG can utilize a diet partially composed of duckweed and better performance was observed with the aid of citric acid

Successful co-feeding of Asian seabass, Lates calcarifer larvae with palm oil-based microdiets and live feeds

Palm oil has been recognized as a high potential alternative dietary lipid source to reduce the reliance on expensive fish oil in aquaculture feeds. Unfortunately, most research studies were focusing on the juvenile or grow-out stage of aquatic species. This study was designed to develop weaning microdiets for Asian seabass larvae with dietary fish oil being replaced with crude palm oil (CPO) at 25, 50, and 75% (CPO25, CPO50, and CPO75) and refined bleached deodorized palm olein, refined palm oil (RPO) at 50 and 75% (RPO50 and RPO75) replacement levels. A fish-oil-based microdiet was used as a control treatment (FO100). The triplicate groups of fish larvae with initial weight and length of 1.71 ± 0.13 mg and 5.54 ± 0.34 mm, respectively, were stocked at 150 larvae/tank and co-fed with the experimental microdiets and live feeds (L-type rotifer and artemia). The final body weight (0.54–0.63 g) and specific growth rate (SGR) (12.8–13.13%/d) of fish-fed palm oil-based diets were significantly better than the control diet (0.42 g; 12.21%/day, respectively). In particular, RPO75 yielded the best SGR followed by RPO50, CPO75, CPO50, and CPO25. The feeding intake and feed conversion ratio (FCR) were not statistically different from other treatments (0.2–0.3 g/fish/d and 1.06–1.63, respectively). The survival rate of larvae-fed palm oil-based diets (33.11–46.67%) during the feeding trial was comparable to the control diet (39.33%). In the 65 ppt-salinity stress test at 25 DPH, there was no significant difference in terms of the survival rate of larvae fed the control diet and the CPO-based diets, but the lowest survival rate was observed in the RPO-based diets than the control diet. Higher final whole-body protein and lipid contents (15.3 ± 0.4 and 3.7 ± 0.0%, respectively) were observed in fish-fed CPO50 compared to other treatments. Generally, the replacement of fish oil with palm oil increased the palmitic acid (C:16:0) and oleic acid (C18:1n9) and significantly reduced the eicosapentaenoic acid (EPA) (C20:5n3) and docosahexaenoic acid (DHA) (C22:6n3) contents in both the microdiets and larval body, a common observation in this kind of investigation. Considering the good growth and survival of Asian seabass larvae in this study, availability of palm oil, and its competitive price compared to fish oil, it is suggested that weaning diets for Asian seabass larvae can be developed using palm oil as a partial source of dietary lipid

Biological development and growth of amur catfish, silurus asotus reared under controlled tropical condition

This study was conducted to investigate the biological development and growth of the Amur catfish, Silurus asotuss at the early larval stage. The eggs and larvae were obtained via the artificial spawning technique. The findings showed that the eggs of the Amur catfish hatched 27 hr after fertilization (hAF) under temperature conditions of 26.9 ± 1.3°C. The newly hatched larvae (4.71 ± 0.87 mm) had a large green yolk sac (0.99 ± 0.02 mm3), unpigmented eyes, undeveloped mouth, and closed anus with one pair of developed maxillary barbels. At the 30 hAH (7.01 ± 0.41 mm), the yolk sac continued to decrease (0.33 ± 0.08 mm3), the barbels elongated, the mouth opened, the lower jaw was movable, with the peristaltic movement of the small intestine detectable. At this point, the larvae started to feed on rotifer and formulated feed. At 72 hAH, larvae (9.02 ± 0.86 mm) had developed pectoral and dorsal fin and at 12 dAH (34.10 ± 0.89 mm) and entered the juvenile stage. This study concluded that the larval development and growth of the Amur catfish is relatively comparable to other tropical catfishes hence similar rearing techniques can be adopted to enhance the overall growth performance at the later stages

Biological development and growth of amur catfish, silurus asotus reared under controlled tropical condition

This study was conducted to investigate the biological development and growth of the Amur catfish, Silurus asotuss at the early larval stage. The eggs and larvae were obtained via the artificial spawning technique. The findings showed that the eggs of the Amur catfish hatched 27 hr after fertilization (hAF) under temperature conditions of 26.9 ± 1.3°C. The newly hatched larvae (4.71 ± 0.87 mm) had a large green yolk sac (0.99 ± 0.02 mm3), unpigmented eyes, undeveloped mouth, and closed anus with one pair of developed maxillary barbels. At the 30 hAH (7.01 ± 0.41 mm), the yolk sac continued to decrease (0.33 ± 0.08 mm3), the barbels elongated, the mouth opened, the lower jaw was movable, with the peristaltic movement of the small intestine detectable. At this point, the larvae started to feed on rotifer and formulated feed. At 72 hAH, larvae (9.02 ± 0.86 mm) had developed pectoral and dorsal fin and at 12 dAH (34.10 ± 0.89 mm) and entered the juvenile stage. This study concluded that the larval development and growth of the Amur catfish is relatively comparable to other tropical catfishes hence similar rearing techniques can be adopted to enhance the overall growth performance at the later stages

Development of sensory organs and changes of behaviour in larvae Amur catfish, Silurus asotus

The development of morphology, sensory organs, and behavioural changes in larvae of Amur catfish (Silurus asotus) were described from 0 h after hatching (hAH) to 20 days after hatching (dAH) reared at 26.7 ± 1.3 °C under controlled conditions. The newly hatched larvae (4.71 ± 0.87 mm) had eyes that were only outlined and unpigmented, no taste buds, and free neuromasts with a demersal swimming mode associated with negative phototaxis and immediate rheotaxis responses. At 12 hAH (5.57 ± 0.25 mm), larvae had pigmented eyes, exhibited initial vertical and horizontal swimming behaviour, and switched to positive phototaxis and positive immediate rheotaxis responses. At 30 hAH (7.01 ± 0.41 mm), larvae with well-developed sensory organs began feeding for the first time, and cannibalistic behaviour was noted for the first time at this stage. At 5 dAH (12.12 ± 0.68 mm), larvae had enlarged taste buds and free neuromasts associated with active swimming behaviour. At 12 dAH (20.22 ± 0.09 mm), the Amur catfish entered the juvenile stage, and at 20 dAH (34.10 ± 0.89 mm), a pair of mandibular barbels degenerated and the fish preferred to remain on the substrate. This study concludes that the development of Amur catfish larval morphology, sensory organs, and behaviour are interrelated and progressively developed as larvae age

Effects of Different Salinities on Growth, Feeding Performance and Plasma Cortisol Level in Hybrid TGGG (Tiger Grouper, Epinephelus fuscoguttatusx Giant Grouper, Epinephelus lanceolatus) Juveniles

Abstract The hybrid TGGG, tiger grouper Epinephelus fuscoguttatusx giant grouper, Epinephelus lanceolatus has a high resistance towards extreme conditions due to its genetic improvement. This study investigated the effects of different salinities on growth, feeding performance and plasma cortisol level in TGGG juveniles. The TGGG juveniles were acclimatized and subjected to 7 different water salinities at 5, 10, 15, 20, 25, 30 and 35 part per thousand (ppt