Pinus tabulaeformis Pollen as Replacement for 17-alpha-methyltestosterone in the Diet of Oreochromis niloticus Larvae for Sex Reversal and Growth

Abstract

Three experiments were conducted to investigate the use of pollen from Pinus tabulaeformis (PP), as a possible replacement for synthetic 17-alpha-methyltestosterone (MT) in Nile tilapia, Oreochromis niloticus larvae diets. In experiment 1, the attractability of a diet containing PP (640mg/kg) compared to a control diet containing no PP was assessed. Experiment 2, lasting 8 weeks, evaluated the effects of PP on growth, food conversion efficiency, survival, and sex inversion compared with that of 17a-methyltestosterone (MT). Results showed that after 60 days of feeding, 100% of Nile tilapia fed the MT diet converted to male; this was statistically similar to the percentage of fish fed the PP diets (81.0% to 89.1% male, p<0.05). Results of the growth trial showed that final weight (FW) and weight gain (WG) of fish fed diets containing 0.08 g/kg PP and 0.64 g PP/kg were significantly higher than those fed the MT diet (p<0.05). Feed intake (FI) of all experimental fish were statistically similar (p>0.05). The group fed 0.08 g PP/kg diet exhibited significantly higher SGR than the MT group. The MT group exhibited lower food conversion efficiency (i.e. higher FCR) than the control group. Fish fed diets containing 0.08 and 0.64 g PP/kg exhibited better FCR than those fed the MT diet. Survival was statistically similar for all dietary treatments (p>0.05). In experiment 3, fish larvae were fed: no PP (control diet), a medium dose (0.32 g/kg), and a high dose (0.64 g/kg) of PP for 14 days and assayed for alpha amylase and trypsin activities. Results showed that diets containing PP were significantly more attractive to the fish than the control diet (p<0.05) for the first 5 min. At the 6th min, results were statistically similar for both PP diets. In conclusion, PP could replace MT in effecting sex reversal from female to male with statistically similar results; it could also promote better growth and food conversion efficiency at the minimum dietary level of 0.08 mg PP/kg.

The use of plant extracts to control tilapia reproduction: Current status and future perspectives

“…Consequently, the phytochemicals act as “phytoandrogens” that exert functional effects similar to testosterone in animals, elevating male reproductive characteristics (Turan & Akyurt, 2005). The potential of phytochemicals in plant extracts to induce either masculinization or fertility impairment in fish has been harnessed to control prolific breeding in tilapia, with positive results (Ampofo‐Yeboah, 2013; Gabriel et al, 2017; Ghosal et al, 2021; Jegede, 2010; Mukherjee, Ghosal, & Chakraborty, 2015a; Nian et al, 2017; Omitoyin, Ajani, & Sadiq, 2013; Stadtlander et al, 2008). The section that follows describes plant species, the respective phyto‐constituents utilized to overcome unwanted tilapia reproduction and subsequently present results from previous studies.…”

“…Pine pollen can be considered a store of testosterone (Adenigba, Tumbokon, & Serrano‐Jr, 2017; Jones & Roddick, 1988; Saden‐Krehula et al, 1971; Saden‐Krehula, Tajic, & Kolbah, 1979; Velasco et al, 2018; Zhong‐han et al, 1994). The utilization of pollen from Pinus tabulaeformis and Pinus kesiya to produce all‐male individuals of Nile tilapia resulted in considerable increase in the rate of masculinization (Nian et al, 2017; Nieves, 2017; Table 1).…”

“…The accumulation of hormonal residues is facilitated by the hydrophobic nature of MT that allows it to rapidly adsorb onto sediments (Mlalila et al, 2015). The leakages of MT and its metabolites into the aquatic environment from uneaten or un‐metabolized food have the potential to disrupt endocrine and reproductive systems of nontarget aquatic organisms (Abucay & Mair, 1997; Gomelsky, Cherfas, Peretz, Ben‐Don, & Hulata, 1994; Hulak et al, 2008; Nian, Tumbokon, & Serrano‐Jr, 2017; Ramirez‐Godinez et al, 2013; Rivero‐Wendt, Miranda‐Vilela, Ferreira, Borges, & Grisolia, 2013). Further, fish treated with synthetic chemicals are not readily accepted by consumers because of safety concerns (Biswas et al, 2005; Reverter, Bontemps, Lecchini, Banaigs, & Sasal, 2014).…”

The efficacy of using pine (Pinus massoniana) pollen as an alternative to synthetic steroids in producing monosex male Nile tilapia (Oreochromis niloticus, L.)

“…A different species of pine, Pinus tabulaeformis, has also been used as a replacement for 17-alpha-methyltestosterone in the diet of Nile tilapia larvae for sex reversal and growth (Nian et al, 2017).…”

“…A different species of pine, Pinus tabulaeformis , has also been used as a replacement for 17‐alpha‐methyltestosterone in the diet of Nile tilapia larvae for sex reversal and growth (Nian et al., 2017). Pine pollen contains all four major androgen (male sex) hormones, androstenedione, testosterone, dehydroepiandrosterone (DHEA), and androsterone (Danuše, 2019).…”