Genetic Improvement Of Farmed Tilapia Research Articles

Effects of four hormones on the mitigation of ovarian damage in tilapia (Oreochromis niloticus) after copper and cadmium exposure

Female tilapia of the Genetic Improvement of Farmed Tilapia (GIFT) strain were selected as an animal model to study the effects of four hormonal drugs in mitigating ovarian damage following exposure to copper and cadmium. After combined exposure to copper and cadmium in aqueous phase for 30 d, tilapia were randomly injected with oestradiol (E2), human chorionic gonadotropin (HCG), luteinizing hormone releasing hormone (LHRH), or coumestrol and raised in clear water for 7 d Ovarian samples were collected after combined exposure to heavy metals for 30 d and after recovery for 7 d Gonadosomatic index (GSI), copper and cadmium levels in the ovary, reproductive hormone levels in serum, and mRNA expression of key reproductive regulatory factors were determined. After 30 d of exposure to the combined copper and cadmium in aqueous phase, the Cd2+ content in tilapia ovarian tissue increased by 1,242.46% (p < 0.05), whereas the Cu2+ content, body weight, and GSI decreased by 68.48%, 34.46%, and 60.00% (p < 0.05), respectively. Additionally, E2 hormone levels in tilapia serum decreased by 17.55% (p < 0.05). After drug injection and recovery for 7 d, compared to the negative control group, the HCG group exhibited an increase of 39.57% (p < 0.05) in serum vitellogenin levels. Increases of 49.31%, 42.39%, and 45.91% (p < 0.05) in serum E2 levels were observed, and mRNA expression of 3β-HSD increased by 100.64%, 113.16%, and 81.53% (p < 0.05) in the HCG, LHRH, and E2 groups, respectively. The mRNA expression of CYP11A1 in tilapia ovaries increased by 282.26% and 255.08% (p < 0.05) and mRNA expression of 17β-HSD increased by 109.35% and 111.63% in the HCG and LHRH groups, respectively (p < 0.05). All four hormonal drugs, particularly HCG and LHRH, promoted the restoration of tilapia ovarian function to varying degrees after injury induced by combined exposure to copper and cadmium. This study presents the first hormonal treatment protocol for the mitigation of ovarian damage in fish exposed to combined aqueous phases of copper and cadmium as a strategy to prevent and treat fish ovarian damage induced by heavy metals.

The effect of dietary paeonol on growth performance, antioxidant enzyme activities and gene expressions of Genetic Improvement of Farmed Tilapia juveniles (Oreochromis niloticus)

This experiment was conducted to determine the effect of dietary paeonol levels on growth performance, serum biochemical parameters, antioxidant enzyme activities and transcriptional expression of antioxidant- and immune-related genes in Genetic Improvement of Farmed Tilapia (GIFT) juveniles. Six diets supplemented with 0, 60, 120, 240, 480 and 960 mg kg−1 paeonol were formulated, and each diet was randomly assigned to three replicate groups of 25 fish with an average initial weight of 23.10 ± 0.90 g for 53 days. Our results showed that weight gain (WG) increased first and then decreased with the increase of dietary paeonol levels. Serum alkaline phosphatase (ALP), albumin (ALB) and total protein (TP) were significantly increased as the increasing dietary paeonol levels. Lactate dehydrogenase (LDH) contents, alanine aminotransferase (ALT) and aspartate transaminase (AST) activities displayed a trend of decreasing or significantly decreasing in the paeonol-added groups. Supplemental paeonol in diets significantly elevated the activities of catalase (CAT), glutathione peroxidase (GPx) and Lysozymes (LYZ) in both serum and liver, while decreased the malondialdehyde (MDA) values. Furthermore, the levels of dietary paeonol had significant effects on the mRNA expression of antioxidant genes (including CAT, GPx, Maf, HMOX1) and immune genes (including irak1, IL-8, CC1, LYZ). These data suggested that dietary paeonol could improve the growth performance and some serum biochemical indices of GIFT, enhanced the antioxidant enzyme activities, and induced the expression of antioxidant- and immune-related genes. Analysis based on broken-line regression, 90.55 mg kg−1 paeonol would be suitable for tilapia juveniles.

Effects of Elephantopus scaber extract on growth, proximate composition, immunity, intestinal microbiota and resistance of the GIFT strain of Nile tilapia Oreochromis niloticus to Streptococcus agalactiae

This study aimed to investigate the effects of Elephantopus scaber extract on the GIFT (genetic improvement of farmed tilapia) strain of Nile tilapia Oreochromis niloticus. A total of 800 tilapia with an initial body weight of 1.34 ± 0.09 g each were randomly divided into five groups. The tilapia in the control group (E0 group) were fed on a basal diet only. Meanwhile, tilapia in the four experimental groups were fed on a basal diet supplemented with 1 g/kg (E1 group), 3 g/kg (E2 group), 5 g/kg (E3 group), and 7 g/kg (E4 group) of E. scaber extract for 10 weeks. Results showed that the survival rate was higher in the experimental groups than in the control group. Compared with the control group, some growth parameters (FW, WGR, SGR, VSI, and HSI) were significantly improved in the E1 group and E2 group. The crude lipid content in the dorsal muscle and liver was lower in the E1 group than in the control group. After E. scaber extract supplementation, activities of immunity-related enzymes (ACP, AKP, T-AOC, SOD, CAT, GSH-Px and LZM) in plasma, liver, spleen and head kidney, and expressions of immunity-related genes (IL-1β, IFN-γ, TNF-α, and CCL-3) in liver, spleen and head kidney showed various degrees of improvement, while MDA content and Hsp70 expression level were decreased. The survival rate of tilapia increased in all the supplementation groups after Streptococcus agalactiae treatment. E. scaber extract addition changed the species composition, abundance, and diversity of intestinal microbiota in tilapia. These results demonstrate that E. scaber extract supplementation in diet can improve the growth, immunity, and disease resistance of GIFT against S. agalactiae. E. scaber extract supplementation can also change intestinal microbiota and reduce crude lipid content in dorsal muscle and liver. The above indicators show that the optimal dose of E. scaber extract for GIFT is 1 g/kg.

Nutritional value of domesticated duckweed variety DW2602 and its feeding effects on the growth performance and digestive activities of tilapia fingerlings

Duckweeds are a family of fast-growing aquatic plants, in which wild plants of many species have been tested in animal feed. We domesticated a duckweed variety, <italic>Spirodela polyrhiza</italic> DW2602, which had 44.5% protein and 2.6% lysine and was grown in large scale. The effects of DW2602 on the growth performance and the digestive enzyme activities of tilapia variety GIFT (Genetic Improvement of Farmed Tilapia, <italic>Oreochromis niloticus</italic>) fingerlings were evaluated. The dry powder of DW2602 was added to conventional tilapia feed at six inclusion levels of 0%, 10%, 15%, 20%, 25%, and 30%. The diets were fed to tilapia fingerlings with an initial weight of 2.0 ± 0.15 g for 60 days. Results showed that DW2602 improved the growth performance and digestive enzyme activities significantly. The feeding effect was the best when the inclusion rate was 20%, in which the body weight increased to 37.24 ± 1.21 g in 60 days, 18.15% higher than the control (P&lt;0.05). The weight gain rate, the specific growth rate, the condition factor, and the hepatosomatic index of the fish were all significantly hihger than the control (P&lt;0.05), and the amylase, protease, and lipase activities in the digestive system were all promoted by DW2602 (P&lt;0.05). Therefore, the duckweed variety DW2602 has great application prospect in tilapia culture.

Performance of two varieties of Nile tilapia farming in hapas and excavated ponds in Brazil

The great commercial potential of Nile tilapia is due to features such as its high production performance, its adaptability to different farming systems, and the development of genetic varieties with superior performance. Therefore, the objective of this study was to evaluate the performance of two varieties, GIFT (Genetic Improvement of Farmed Tilapia) and Supreme, grown in hapas in concrete tanks and grown in excavated ponds. Were used 200 and 1234 fingerlings of both varieties, GIFT and Supreme (average initial weight of 0.83 g), for farming in hapas and ponds, respectively. Biometric measurements were taken at four farming stages (fingerling, juvenile, growth, and fattening). Were measured weight (g), total length (cm), standard length (cm), trunk length (cm), head length (cm), head height (cm), body height (cm), weight gain (g) and head/edible-part ratio. For all parameters and in all stages, superior results were observed for tilapia reared in excavated ponds. When the varieties were compared, GIFT had the best performance for most parameters in the fingerling stage, and for weight, total length, and body height in the juvenile stage. Both varieties grew better in excavated ponds. Moreover, GIFT showed higher growth than Supreme during all stages when grown in excavated ponds. Supreme showed higher growth than GIFT in hapas only in the growth stage. Thus, it is concluded that the rearing in excavated ponds provided better results, with superiority of the GIFT variety, which was more able to take advantage of the favorable conditions of this system.

Ferulic acid: A natural compound as an efficient feed additive for GIFT (Oreochromis niloticus)

This study aimed to investigate the effect of dietary ferulic acid (FA) supplementation on growth performance, antioxidant capacity and some physical characteristics of flesh in genetic improvement of farmed tilapia (GIFT) juveniles. Five diets supplemented with 0, 50, 100, 200 and 400 mg/kg FA were prepared. Weight gain was significantly increased, while feed conversion ratio, viscerosomatic index and hepatosomatic index were significantly decreased in fish fed FA diet at 100 mg/kg feed (p < .05). FA supplementation improved hepatic and serum superoxide dismutase and catalase activities, but decreased the malondialdehyde content (p < .05). Furthermore, with the addition of FA, serum triacylglycerol, cholesterol, low-density lipoprotein cholesterol contents, alanine aminotransferase and aspartate transaminase activities were reduced, whereas serum high-density lipoprotein cholesterol content, alkaline phosphatase and lysozyme activities were enhanced. The texture profile analysis parameters and water-holding capacity tended to increase while cooking loss was decreased by dietary FA supplementation (p < .05). These results suggested that dietary FA supplementation increased the growth performance and antioxidant capacity of GIFT, and improved some physical characteristics of flesh and serum biochemical parameters. The optimum dietary FA level was 100 mg/kg in diet.

Morpho-functional response of Nile tilapia (Oreochromis niloticus) to a homeopathic complex

This study evaluated the performance, prevalence of ectoparasites and morpho-functional response of the liver and the branchiae of Nile tilapia (Oreochromis niloticus) raised on fish meal with added of the homeopathic complex Homeopatila 100(®) at different concentrations. Post-reversed juvenile Nile tilapia (O. niloticus) of the GIFT (Genetic Improvement of Farmed Tilapia) strain were used in this study. The performance, ectoparasite prevalence and parasite load in the branchiae and skin as well as the liver and branchial histology. Fish were randomly assigned to receive one of four treatments: control, 20mL hydroalcoholic solution (alcohol 30°GL); 20mL Homeopatila 100(®) per kg of meal; 40mL Homeopatila 100(®) per kg of meal; or 60mL of Homeopatila 100(®) per kg of meal, compared to control with out the addition of the complex. There were four replications per treatment type (16 experimental units total) at a density of 40 fish per m(3) over a period of 57 days. The Kruskal-Wallis H test (p<0.05) was employed to analyse the physical and chemical parameters of water as well as for parasite prevalence; whereas analysis of variance was used for liver performance. If the values were significant (p<0.05), they were compared by Tukey's test. Multiple comparisons of averages were performed using Student's t test (p<0.05). There were no significant between the physical and chemical parameters of the water between the different groups at the end of the experiment. Significant differences (p<0.05) in the mixed parasite conditions were found within the different Homeopatila 100(®) treatments. The hepatosomatic ratio of fish treated with Homeopatila 100(®) was significantly lower than that of fish from the control group. The best results in the liver and branchiae occurred in fish receiving Homeopatila 100(®) at 40mL/kg in terms of the number of hepatocytes/mm(2), the intercellular glycogenic behaviour, the rates of histological changes (hyperplasia, lamella fusion and telangiectasia) and the percentage of neutral and acidic mucin-producing cells. The addition of Homeopatila 100(®) at a concentration 40mL per kg/meal to the diet of juvenile Nile tilapias resulted in improved hepatocytes and intracellular glycogen levels as well as the lowest mean rate of branchial histological changes with an increase in acidic mucin-producing cells compared to neutral mucin-producing cells, compared to control.

Use and exchange of aquatic genetic resources in aquaculture: information relevant to access and benefit sharing

Use and exchange of aquatic genetic resources in aquaculture: information relevant to access and benefit sharing

Use and exchange of genetic resources of Nile tilapia (Oreochromis niloticus)

AbstractThe worldwide use of Nile tilapia (Oreochromis niloticus Linnaeus, 1758) in aquaculture represents a somewhat unique scenario. The natural distributions and global genetic resources of tilapias are in Africa, yet the main centers of utilization for aquaculture are primarily in Asia. Within a few decades, Nile tilapia graduated from being an ‘orphan commodity’ (i.e. of interest to only resource‐poor fish farmers) to a globally traded commodity. Most aquaculture production of Nile tilapia in Asia and elsewhere has relied on a narrow genetic base. The natural genetic resources have not yet been fully documented and tapped for use in aquaculture, and many natural populations are under severe threat of irreversible change or loss. Although genetic improvement is now well underway, an important question is how the wealth of Nile tilapia wild genetic resources shall be used for the benefit of a wide range of users, at present outside Africa. This review focuses on documenting the status of Nile tilapia genetic resources (including the potential threats), providing a case for their conservation and for the judicious utilization of genetic diversity for the benefit of all stakeholders; and on analysis of the lessons learnt from a major Nile tilapia genetic improvement initiative, the genetic improvement of farmed tilapia (GIFT) project. Information about other genetic improvement efforts by means of hybridization, sex reversal and YY male technology is also presented.

Performance e retenção de metais pesados em três linhagens de juvenis de tilápia-do-Nilo em hapas

This essay aimed to evaluate the productive performance of three Nile tilapia (Oreochromis niloticus) strains, GIFT (Genetic Improvement of Farmed Tilapia), Bouake and Chitralada, during the production of juveniles from February to May, 2007. The sexually reverted fingerlings were stored in twelve 9 m3 hapas installed in a ponds with 0.7 ha water blade. At the end of 93 days of culture a significant change in survival among the three strains (P0.05). The average of fish weight more than 25g was over 80% of the lots, which guaranteed the juvenile uniformity and standardization. The toxic metals cadmium and lead were above the tolerable level in the fish, although the chromium metal was not detected. The GIFT strain presented the best performance in this culture system, although it contained high indexes of heavy metals in comparison with the other two strains.

ANALISIS KERAGAMAN BENTUK TUBUH IKAN NILA STRAIN GIFT PADA TIGA TINGKATAN UMUR YANG BERBEDA

A study aimed to identify morphology variability of nile tilapia (Oreochromis niloticus) strain GIFT (Genetic Improvement of Farmed Tilapia) by using standard measurement and multivariate analysis method was conducted. Elevan characters were measured at 141 fishes representing 3 levels of age (0-3 month, 3-6 month and more than 6 month) of nile tilapia strain GIFT. Multivariate analysis of variance (manova) and Pricipal Component Analysis (PCA) were applied to explore the morphological variability.The result showed that body shape of fry (0-3 month of age) was different from fishes with 3-6 month of age (consumption size), also from the broodstock. At the early level of age, development of the body shape was growth in width and length. At the consumption size and broodstock levels, the development of body shape was growth in fat too.