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| Impact of Culture Pattern and Light Intensity on Growth in Pacific White Leg Shrimp and on Water Quality |
| YU Zhenjie,ZHANG Wenbo,LIU Qigen |
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Abstract Pacific white leg shrimp (Litopenaeus vannamei) was reared in an indoor tank under conditions of monoculture at natural light (group A1 ) ,monoculture at low‐light (group A2 ) ,loach(Misgurnus an‐guillicaudatus)‐shrimp polyculture at natural light (group B1 ) ,loach‐shrimp polyculture at low‐light (group B2) ,silver carp(Hypophthalmichthys molitrix) bighead carp (Aristichthys nobilis) and shrimp polyculture at natural light (group C1 ) ,silver carp ,bighead carp ,and shrimp polyculture at low‐light (group C2 ) ,silver carp ,bighead carp ,shrimp and loach polyculture at natural light (group D1 ) ,and sil‐ver carp shrimp ,bighead carp ,and loach polyculture (group D2 ) at low‐light for 70 days .During the ex‐periment ,growth ,feed utilization and yield were measured and water quality including chemical oxygen demand (COD) ,and levels of NO3‐N ,NO2‐N ,NH3‐N ,total nitrogen (TN) ,total phosphorus (TP) and dissolved oxygen (DO) was determined in a 15 or 20 day interval .Results showed that the shrimp in mon‐oculture at natural light had significantly larger size than the shrimp in the other groups (P<0 .05) ,while the shrimp in monoculture under low‐light had significantly smaller size than the shrimp in the other groups (P<0 .05) ,without significant differences in the other groups .There were significantly higher food conversion ratio (FCR) and survival rate in the monoculture than those in the polyculture and signifi‐cantly higher FCR and survival rate under natural light that at low‐light (P<0 .05) .During the experi‐ment ,levels of NO3‐N ,NO2‐N ,and NH3‐N were steady elevated ,significantly higher nitrite level in group A and group B than those in group C and group D (P<0 .05) ,and significantly lower at natural light than at low‐light .There was significantly higher ammonia level in group A than those in the other groups (P<0 .05) .The findings show that proper lighting is an important factor in the growth of the shrimp ,and that loach can effectively improve the economic benefits of shrimp ponds .Silver carp and big‐head carp ,however ,can effectively improve the ecological benefits and yield of shrimp ponds .
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Received: 25 April 2016
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