Growth Performance Comparison of Sex Reversed Oreochromis Macrochir (Boulenger, 1912), Oreochromis Andersonii (Castelnau, 1861) and Oreochromis Niloticus (Linnaeus, 1758) Juveniles Under Pond Culture (original) (raw)
Related papers
2015
The aim of this research was to determine age of Oreochromis niloticus fry after hatching for efficiency of 17-α methyltestosterone on sex reversal. The study was carried out in Zoology Laboratory, University of Eldoret. Fish were seined from University of Eldoret fish farm and those brooding eggs and fry were selected. Fry were fed using the feed containing 17 α methyltestosterone for varying periods of days. The period of exposure to hormone feed were distributed into 21 days, 30 days, 42 days and 60 days. And at the end of each period, the fry were then sampled in three replicates of ten fry for dissection and microscopic examination. The data was statistically analyzed using Two-way Analysis of Variance and correlations, Statistical Programme for Social Scientists and Excel Statistical package. In all the treatments, no pure females were observed but intersex of varying number of ova was observed. The yolk sac fry from the incubator had 100% conversion efficiency into males both...
Growth Performance of Hormonal Sex-reversed and Mixed Sex Tilapia.pdf
This study investigates the performance of all male and mixed sex tilapia (Oreochromis niloticus) raised in outdoor rearing conditions. All male tilapia were obtained by hormonal administration of 17 α-methyltestosterone (30 μg) into the diet of hatchlings of O. niloticus and fed them for 28 days. Both sex-reversed male and mixed sex O. niloticus were fed with coppens® commercial diet and replicated thrice at 45% crude protein for 24 weeks Biological evaluation such as Mean Weight Gain (MWG), Specific Growth Rate (SGR) and Feed Conversion Ratio (FCR) were determined. Temperature, pH, conductivity and total dissolved solids were measured using standard methods. Data were analyzed using descriptive statistics and ANOVA at P=0.05. Result revealed that all male tilapia had significant weight gain (p<0.05) (5.93 ± 0.13 g) compared to the mixed sexes (2.19 ± 0.09 g). However, breeding activity was not noticed within the mixed sex tilapia population after a culture period of six months. Hence, poor performance could not be directly linked to spawning activity. The value of temperature, pH, conductivity and total dissolved solids were closely related and were within recommended range for the culture of tropical fishes. It was therefore hypothesized that 17 α-methyltestosterone besides achieving masculation, may have growth promoting characteristic. The detail mechanism responsible for this better performance could be the focus of future research.
Our Nature, 2015
17 α-Methyltestosterone (MT) is a commonly used synthetic androgen for the all male tilapia fry production. The probable residual effect of MT on human health and environment has been a concern. Two trials for two seasons were conducted to evaluate the effectiveness of carp testis (CT), as a source of natural androgen, on sex reversal of Nile tilapia (Oreochromis niloticus) and compare it with MT at Department of Aquaculture, Agriculture and Forestry University, Nepal,using completely randomised block deign (RCBD). Altogether 8 treatments with 4 for methyltestosterone (40 mg MT kg-1 of diet) and 4 for 75% rohu (Labeo rohita) testis. Both source of androgen were fed for 15, 18, 21 or 24 days. Treatments were replicated thrice. The result of methyltestosterone feeding for 24 days showed significantly (p<0.05) higher percentage of male (98.5±1.5) than 15 days (87.1±3.5) but was statistically similar with 18 (91.8±2.6) and 21(94.3±3.0) days feeding. Similarly percentage of male obtai...
2015
This paper describes the optimization of dose of methyltestosterone (MT) hormone for masculiniza ti on of ti la pia (Oreoclzromis nilolicus). Five treatments (i.e. T 1> T 2, T 3, T_1 and T 5) with different doses such as 0, 40, 50, 60 and 65 mg of MT hormone were mixed with per kg of feed for each treatment and fed the fry four times a day up Lo satiation for a period of 30 days. The stocking density was maintained 10 spawn/liter of waler. The growth of fry at different treatments was recorded weekly and mortality was recorded daily. AL the end of hormone feeding the fry were reared in hapas fixed in ponds for another 70 days and at the lOOth day the fish were sexed by the gonad squashing and aceto-carmine staining method. The analysis of growth data did not show any significant variation in length and weight of fish among the different treatments. High mortality of fry ranging 66% to 81.6% was observed in different treatments and highest mortality was observed during the first t...