College of Agricultural Sciences and Fisheries Technology

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Browsing College of Agricultural Sciences and Fisheries Technology by Author "Assam, Julius Michael"

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    The effect of pawpaw (Carica Papaya) seeds on Gonadal development of Nile. Tilapia ( Oreochromes Niloticus) and their growth performance compared to hormonal sex—reversed O, Niloticus reared in concrete tanks
    (University of Dar es Salaam, 2016) Assam, Julius Michael
    This study was designed to determine the effect of pawpaw ( Carica papaya ) seeds on gonadal development of Nile tilapia (Oreochromis niloticus) and their growth performance compared to hormonal-sex-reversed fish of the same species reared in concrete tanks. The experiment was run by feeding newly hatched fry (mean weight 0.074 ± 0.01 g) with five different diets containing 30 g pawpaw seed (PSD l ), 60 g of pawpaw seed (PSD2), 120 g of pawpaw seed (PSD3), 60 mg of l7a-MT hormone (MTI-J) and control (CD) for 23 days. Thereafter, twelve 0.niloticus fry with in initial mean weight of 0.07 ± 0.01, 0.12 ± 0.06 and 0.06 ± 0.01 g were separately stocked in triplicate tanks and fed on control diet (CD), for 63 days to monitor their growth performances. Fish fed on pawpaw seeds diets were histologically examined for their gonadal effect and any changes on their external morphology . The results showed growth of pimp les, erosion of the fins in all fish fed on pawpaw seeds, rupture in the testis of 0. niloticus fed on PSD2 and PSD3 and development in the testis of fish fed on PSD 1 but no effect was observed in the ovary. Survival rate ranged between 46.65 ± 4.28 to 49.84 ± 2.8 l % while Final weight gain was higher i n PSD3 (15.00 ± 0.83) and lower in PSD J ( 10.96 ± 0.69). The results showed higher yield in PSD3 (1o1 ± 5.85 g) and lower i n PSD I (67 .68 ± 5.17 g). However no significant differences in growth were observed in both fish fed on pawpaw seeds and MT hormone diets (P = 0.740). The study suggests further research to identify causes of erosion and usually observed on the fins of 0. niloticus fed on pawpaw seeds diets.