Abstract. Yousif RA, Choudhary MI, Ahmed S, Ahmed Q. 2020. Review: Bioaccumulation of heavy metals in fish and other aquatic organisms from Karachi Coast, Pakistan. Nusantara Bioscience 13: 74-85. Heavy metals are being utilized in a variety of ways in industries, agriculture, food processing and household in many forms. Metals are unique environmental and industrial pollutants in the sense that they are neither created nor destroyed by human beings but are only transported and transformed into various products. The present study deals with the findings of various investigators on the effect of heavy metals on fish and other aquatic organisms on Karachi coasts of Pakistan. The polluted areas (Rivers and Karachi coasts) receiving effluents from industrial, agricultural, municipal and domestic wastes. The order of abundance of the metals were as fellow; Fe > Zn > Cu > Mn > Cd > Pb > Cr > Ni > Hg > As. Most studies showed that essential metals (Fe, Zn, Cu, and Mn) in aquatic organisms are much high, but the quantities of non-essential metals are found to be less. This review has shown that fish and other aquatic organisms are used as bio-monitoring species in heavy metal pollution. It is suggested that such investigations should be continuous in terms of both human health and determination of metal pollution in aquatic environment.

Abstract. Mohammed FA, Yousif RA, Hilal FM, Adam RA, Ahmed TK. 2020. The effect of dietary methionine levels on growth, feed conversion and protein retention efficiency of Nile Tilapia (Oreochromis niloticus) fingerlings. Nusantara Bioscience 12: 21-27. A 49 days feeding trial was conducted to evaluate growth, feed utilization and body composition of Nile tilapia Oreochromis niloticus (4.30±0.01 g), fed five isonitrogenous (32 g 100 g-1 crude protein) and isoenergetic (14.51 kJ g-1 Gross energy) practical diets and five levels of methionine supplementation (0.5, 1, 1.5, 2 and 2.5 g 100 g-1). The experimental design was completely randomized with five treatments and three replicates. Fish were stocked in triplicate groups of 20 fish held in 70 L flow-through tanks (water volume 55 L) and fed twice daily (08:00 am and 04:30 pm) to apparent satiation. When absolute weight gain (AWG; g fish-1), feed conversion ratio, protein deposition (g fish-1) and protein retention efficiency (%) data were subjected to second-degree polynomial regression analysis 95% of the plateau of the above parameters was achieved at dietary methionine concentrations between 1.4-1.5 g 100 g-1 dry diet or 0.09-0.10 g methionine kJ-1 GE. Corresponding to 4.4-4.7 g 100 g-1 of the dietary protein. Based on these results, dietary methionine requirement for Nile tilapia Oreochromis niloticus is recommended 1.4-1.5 g 100 g-1 diet.

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and Technology during the period 15/07-02/09/2018 to determine the effect of replacing fishmeal with baobab seed meal in the formulation of diets for Nile Tilapia (O. niloticus) fish and determining effect on the growth rate. The experiment included 12 plastic aquariums, Fish were distributed randomly in aquariums and placed in each one 10 fish. Acclimatized to the hatchery conditions for 3 days, before the beginning of the experiment. The experiment included 4 treatments with 3 replicated aquariums for each. Feeds T0, T1, T2 and T3 (The diets replacing 0, 25, 50 and 75% of fish meal protein content by baobab seed meal. The results indicated that final body weight (BW), weight gain (WG) and specific growth rate (SGR) of O. niloticus increased with increasing level of fish baobab seed meal in diets. WG was found 20.10, 28.23 and 37.90 for T1, T2 and T3 respectively. The data were analysed by one-way analysis of variance (ANOVA, F test) and LSD for significantly different means at a significance level of 0.05 using SPSS version 16.

This study was conducted to determine the dietary total aromatic amino acid requirement and tyrosine replacement value for phenylalanine for fingerling Oreochromis niloticus by conducting two 8‐week experiments. In experiment I, phenylalanine requirement was determined by feeding test diets (350 g kg–1 CP; 16.72 kJ g–1 GE) with graded levels of phenylalanine (4, 6.5, 9, 11.5, 14 and 16.5 g kg–1 dry diet) at a constant level (10 g kg–1) of dietary tyrosine to triplicate groups of fish (1.65 ± 0.09 g). Quadratic analyses of absolute weight gain (AWG), protein deposition (PD%) and phenylalanine retention efficiency (PRE%) indicated the requirement at 12.1 g kg–1 dry diet. In experiment II, six diets with different levels of L‐tyrosine (2.0, 4.0, 6.0, 8.0, 10.0 and 12.0 g kg–1 dry diet) with 12.1 g kg–1 phenylalanine as determined in experiment I fixed in all the test diets were fed to fish (1.67 ± 0.17 g) to determine the tyrosine requirement under same conditions. Quadratic regression analysis of AWG, PD and PRE demonstrated the tyrosine requirement at 8.5 g kg–1 dry diet, corresponding to 24.2 g kg–1 of dietary protein. Based on the above data, the total aromatic amino acid requirement was found to be 20.6 g kg–1 of dry diet, corresponding to 58.8 g kg–1 of dietary protein, and tyrosine replacement value for phenylalanine was found to be 37% on a molar basis.