Effects of different bransof feeds on growth ofblack tiger shrimp( Penaeus monodon) and water quality

To investigate the effects of different brands of commercial diets (D1, D2, D3, D4, D5 and D6) on the growth performance of black tiger shrimp (Penaeus monodon) and water quality, we fed the shrimps average initial wet weight (2.820.02) g with 6 diets for 60 d. The results show that the weight gain and special growth rate of shrimps fed with D1, D5 and D6 are significantly higher than those with D2 and D4 (P0.05), and the feed conversion ratios of shrimps fed with D5 and D6 are significantly lower than those with D2 and D4 (P0.05). The apparent protein digestibility of shrimps fed with D4 and D5 is much higher than those with D1~D3 (P0.05). At 20th day, the chemical oxygen demand (COD) with D1 treatment is the lowest and significantly lower than that with D5 and D6(P0.05). At 40th day, the COD with D5 and D6 treatments are significantly lower than that with D1~D4 treatments (P0.05). The NH4+-N with D2 treatment is the lowest and significantly lower than that with D4~D6 treatments (P0.05), and the total nitrogen (TN) and total phosphorus (TP) are the lowest with D4 and D6 treatments. At 60th day, the NH4+-N with D1 treatment is the lowest and significantly lower than that with the other treatments except D2 treatment (P0.05), and the TN with D5 and D6 treatments are significantly lower than that with D1~D4 treatments (P0.05), but the TP with D2 treatment is the lowest and significantly lower than that with D1 and D4 treatments (P0.05). The excretion rates of nitrogen with D1 and D6 treatments are the lowest and significantly lower than that with the other diet treatments (P0.05). The minimum excretion rate of phosphorus is with D1 treatment. In conclusion, the shrimps fed with D1, D5 and D6 perform better in growth, and D1, D5 and D6 diets have minimal pollution to the water.