Effect of pawpaw (Carica Papaya) seed meal on growth performance, feed utilization, survival and masculinization of sexualy undifferentiated three spotted Tilapia (Oreochromis Andersonii) fry
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Date
2019
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Publisher
University of Namibia
Abstract
The objective of this study was to determine the effects of dietary Carica papaya seed meal supplementation at different levels on growth performance, feed utilization, survival rate and sex ratio of sexually undifferentiated three spotted tilapia (Oreochromis andersonii) fry. Six treatments (replicated thrice) were designed based on the control (basal diet), 17 α-methyltestosterone (MT) (60 mg) and C. papaya seed meal incorporated into tilapia feed at 5, 15, 25 and 35 g / kg diet and administered to freshly hatched fry (9 days old) for 120 days. The swim up fry (initial body weight 0.04 g / fry) were collected from the aquarium and randomly distributed (𝑛=80) at each of eighteen black bins with a holding capacity of 200 L. The results showed that the growth performance of the fish fed varying inclusion levels of pawpaw seed meal did not differ significantly from those fed basal diet and 60 mg of MT. A decrease in growth performance and poor feed utilization capacity was observed in the treated fish with increasing dietary C. papaya inclusion levels from 15 g / kg to 35 g / kg diet, suggesting that it had inhibited the growth at high dosage. Pawpaw seed meal was able to skew the sex ratio in favour of males, from the expected ratio of 1:1 male: female for all the treatments. The percentage of males increased for the treatments with increasing the dietary inclusion level, with the highest masculinization percentage (82%) (P < 0.05) observed in fish fed with 15 g and 35 g of C. papaya extracts / kg diet. Dietary C. papaya did not significantly change the fish survival rate among the treatments (P > 0.05), signifying that it had no lethal effect. This study showed the possibility of using pawpaw seed meal as a natural agent to induce sex reversal in three spotted tilapia. Due to the safety, ease of biodegradation and local availability of this naturally sourced sex reversal agent, the study recommends that, it could be used as a viable alternative to popular synthetic hormones. In order to improve growth and induce sex reversal at the same time, the study recommends the use of 5 g but not ≥ 15 g C. papaya extracts / kg diet to be economically viable and efficient for fish farms.
Description
A thesis submitted in fulfillment of the requirements for the Degree of Master of Science in Fisheries and Aquatic Sciences
Keywords
Carica papaya, Aquaculture, Reproduction, Oreochromis andersonii, Sex reversal