Control of prolific reproduction is vital for a profitable tilapia aquaculture enterprise. All-male tilapia culture is a popular method used to control prolific breeding, because the male individuals grow faster than female and mixed-sex populations. Presently, most farmers use 17α-methyl testosterone (MT) to produce all-male tilapia individuals, although synthetic hormones are linked to human health and environmental risks. Recently, considerable attention has focused on plant-based products as alternatives to MT, because they are affordable, safe, and eco-friendly. Despite the growing interest in using plant extracts to prevent frequent spawning in tilapia production, the available information is not collated to standardize application guidelines. Accordingly, this review article consolidates existing knowledge on the use of plant extracts to control prolific breeding in tilapia culture systems. In addition, limitations to commercial application of the extracts are identified. To date, seed, root, and leaf extracts of 20 plant species, most notably, Tribulus terrestris, Mucuna pruriens, and Carica papaya, exhibit potential for controlling unwanted breeding in tilapia production systems. The extracts are mainly administered orally, incorporated in fish feeds. Saponins and flavanoids are the main bioactive compounds in the phytoextracts,

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Locally available nutrient materials (Cow dung, Soybean extracts and Diammonium Phosphate (DAP)/UREA) were used to prepare culture media for growing Chlorella spp. and compared to the commonly constituted Bold's Basal Medium (BBM) as a control. Algae was cultured in 25L rectangular glass tanks with 24 hour illumination and aeration. Ammonia, pH and counts of algae cells/ml were recorded daily for 24 days. Chlorella spp. production rate, effect of intrinsic ammonia and pH on culture performance, duration of culture cycle and the di fferences in resultant fatty acid composition of the algae were tested. Results indicated a significant effect of culture media on the growth performance of Chlorella spp. (F = 3.42, P< 0.05), although the interaction between time (day) and nutrient media was also significant (F = 17.27, P< 0.05). Bold's Basal Media had significantly lower mean abundance of Chlorella spp. per millilitre than all the other media (F = 20.65, 13.57±7.1×10 4 , P< 0.05). However, Soybean media supported significantly higher densities of Chlorella spp. than other media (F = 20.65, 20.65, 21.53±7.4×10 4 , P< 0.05). The abundance of Chlorella in DAP/UREA and Cow dung media did not differ significantly (F = 20.65, 17.01×10 4 ±4.3 and 18.43±6.0×10 4 , P = 0.46 respectively). There was a notable positive effect of pH on growth of Chlorella whereas ammonia did not have much impact even at relatively high concentrations (236.095 mg l -1 in DAP/UREA). Of the fatty acids in Chlorella, polyunsaturated fatty acids (>40% of Total Fatty Acids) were predominant in all media. Monounsaturated fatty acids (MUFAs) were recorded low (<5% TFA) for Cow dung, BBM and Soybean. DAP/UREA was superior for MUFAs and HUFAs. The results from this study demonstrated the feasibility of cultivating Chlorella spp. using locally prepared nutrients.