Effects of varying dietary levels of <i>Carica papaya</i> seed meal powder (PSM) on growth and histology of gonads in <i>Oreochromis niloticus</i> larvae

Abstract

Sex control in tilapia should provide an invaluable benefit to aquaculture. The effects of different dietary levels of papaya carica seed meal powder on growth and gonad histology in Oreochromis niloticus larvae were studied to prevent early maturity and uncontrolled spawning. Four (4) dietary level of seed meal powder, varying from 0 g.Kg-1 as a control; 1 g.Kg-1 ; 2 g.Kg-1 to 3 g.Kg-1 were each tested in triplicate. The diet were isonitrogenous and were fed to twelve (12) experimental groups of 110 larvae weighing 0.019 g at a feeding rate of 4% body weight, three times a day for 30 days with the experimental diet and then after fed with the basal diet for other 60 days of the experiment. At the end of the experiment, 24 fish from all replicates were randomly sampled, slaughtered and dissected to remove testicles and ovaries. Testicular and ovarian sampleswere fixed in 10% buffered formalin for 24 h before the histological process. After 90 days of experiment, fish weight increased from 0.019 g ± 0.09 to 32.47g ± 0.02; 30.40g ± 0.05; 34.68 g ± 0.07 and 33.83 g ± 0.09 respectively for C. papaya dosage of 0; 1; 2 and 3, respectively. In fish treated with 0 and 1 g.Kg-1 of PSM, the testes showed different stages of spermatogenesis with germ cells moving up to the spermatozoa. Similarly, the ovaries showed follicles at different stages of folliculogenesis up to vitellogenesis. The main lesional changes observed concerned the testicles of fish fed with 2 and 3 g.Kg-1 PSM with in particular the scarcity of germ cells and spermatozoa. For females, the only observations concern vitellogenesis which are important for treatment doses of 0 and 1 g.Kg-1 , while they decrease in the group treated with 3 g.Kg-1 .

Influence de la température sur la spermatogénèse chez le tilapia du Nil, <i>Oreochromis niloticus</i> (Linnaeus, 1758) : une synthèse

“…La spermatogénèse est un processus biologique complexe de transformation cellulaire qui permet la production de cellules germinales haploïdes mâles à partir de cellules souches diploïdes (De Alvarenga et De França, 2009;Magblenou et al, 2019;Xie et al, 2020;Sharma et al, 2023). A la différence des mammifères, la spermatogénèse chez les téléostéens en général et chez le tilapia du Nil en particulier, se déroule à l'intérieur des unités spermatogéniques appelées cystes (De Alvarenga et De França 2009;Schulz et al, 2005Schulz et al, , 2010Melo et al, 2016;Scaia et al, 2020).…”

Effect of pawpaw seed meal using various inclusion level on the gonad structure of Oreochromis Niloticus (gift)

“…Moreover, Burden [5] opines that Tilapia is cultured in no less than 85 nations on the globe. Tilapia is labelled ''aquatic chicken'' since it can be farmed commercially in an extensive variety of methods starting from the simple backyard methods to extremely intensive method or "factory farm" just like in poultry [6]. In majority of developing nations where tilapias are often cultured in cages, ponds, raceways, concrete tanks, as well as rice fi eld are as a result of its characteristics which makes it appropriate for culturing [7].…”

“…Int J Aquac Fish Sci 7(3): 024-029. DOI: https://dx.doi.org/10.17352/2455-8400.000069 to alleviate this limitation include culturing of all-males which is mono-sex by means of exogenous hormone for sex reversal of sexually the same fi sh, predator usage, cage/ tank culture, sterilization, high stocking density, sporadic or selective cropping, and usage of slow growing tilapia species [6][7][8]. Regardless of all the techniques examined, hormone initiation before population of monosex appears to be the most encouraging and satisfactory method [9].…”

“…On the other hand, there is need to investigate less expensive, suitable technology which does not pose a risk to human and environmental health in solving the diffi culties of uncontrolled tilapia breeding. The botanical name of pawpaw is Carica papaya and it is one of the economically signifi cant fruit trees in the Caricaceae family [6,12]. It contains folate, dietary fi ber and vitamin A, C and E. It is very rich in antioxidant nutrients.…”