به كارگيري نسبت هاي مختلف كربن و نيتروژن ورودي به يك سازگان مدار بسته پرورش كپور معمولي (Cyprinus carpio) بدون تعويض آب و بررسي روند تغييرات كيفي آب و تشكيل رشته هاي زيستي (Bio-Floc)

Evaluating the water quality changes and formation of Bio-Floc in a zero-exchange water of common carp (Cyprinus carpio) culture system using different ratios of carbon to nitrogen (C:N

ﺑﻪﮐﺎرﮔﯿﺮي ﻓﻨﺎوري ﺳﻮﺳﭙﺎﻧﺴﯿﻮن ﻓﻌﺎل ﻣﺘﮑﯽ ﺑﺮ ﻋﻤﻠﮑﺮد رﺷﺘﻪﻫﺎي زﯾﺴﺘﯽ )Bio-Floc(، ﻋﻤﻠﮑﺮد ﺑﻬﺘﺮي را در ﺣﺬف ﺗﺮﮐﯿﺒﺎت ﻧﯿﺘﺮوژندار در ﺳﺎﻣﺎﻧﻪﻫﺎي ﻣﺪارﺑﺴﺘﻪ دارد. ﻟﺬا، در ﯾﮏ ﻃﺮح آﻣﺎري ﮐﺎﻣﻼً ﺗﺼﺎدﻓﯽ ﺷﺎﻣﻞ ﺳﻪ ﺗﯿﻤﺎر ﺑﺎ ﻧﺴﺒﺖﻫﺎي ﻣﺨﺘﻠﻒ ﮐﺮﺑﻦ ﺑﻪ ﻧﯿﺘﺮوژن )C:N( و ﻧﺴﺒﺖﻫﺎي 10 ، 15و 20 ﺑﻪ ﻣﺨﺎزن ﭘﺮورﺷﯽ ﻣﺎﻫﯽ ﮐﭙﻮر، اﯾﻦ ﻋﻤﻠﮑﺮد ارزﯾﺎﺑﯽ ﺷﺪ . ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ اﻓﺰاﯾﺶ وزن اﻧﻔﺮادي در ﺗﯿﻤﺎر 10 ﺑﻪﻃﻮر ﻣﻌﻨﯽدار ﭘﺎﯾﯿﻦﺗﺮ از ﺗﯿﻤﺎرﻫﺎي 15 و 20 ﺑﻮد )p<0/05(. وزن ﺑﭽﻪﻣﺎﻫﯿﺎن از 70ﮔﺮم در ﺗﯿﻤﺎرﻫﺎي 15 ،10و 20 ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﻪ 704/7 ،552/8و 708/8ﮔﺮم رﺳﯿﺪ. ﺿﺮﯾﺐ ﺗﺒﺪﯾﻞ ﻏﺬاﯾﯽ و ﻣﻘﺪار آﻣﻮﻧﯿﺎك و ﻧﯿﺘﺮات در ﺗﯿﻤﺎر 10 ﺑﻪ ﻃﻮر ﻣﻌﻨﯽدار ﺑﺎﻻﺗﺮ از ﺗﯿﻤﺎرﻫﺎي 15 و 20 ﺑﻮد )0/05>p(. ﻣﻘﺪار آﻣﻮﻧﯿﺎك در ﺗﯿﻤﺎرﻫﺎي 10، 15 و 20 ﺑﻪﺗﺮﺗﯿﺐ mg/L 29/9 ،78 و 29/9 در ﭘﺎﯾﺎن آزﻣﺎﯾﺶ ﺑﻮد. روﻧﺪ ﮐﺎﻫﺸﯽ pH در ﻫﻤﻪ ﺗﯿﻤﺎرﻫﺎ ﺗﺎ ﭘﺎﯾﺎن آزﻣﺎﯾﺶ ﻣﺸﺎﻫﺪه ﺷﺪ و در ﺗﯿﻤﺎر 20 ﮐﻤﺘﺮﯾﻦ ﻣﻘﺪار را ﻧﺸﺎن داد. ﺑﺎ ﺷﺮوع آزﻣﺎﯾﺶ ﯾﮏ روﻧﺪ اﻓﺰاﯾﺸﯽ در ﻫﺪاﯾﺖ اﻟﮑﺘﺮﯾﮑﯽ آب )EC( و ﺗﻮﻟﯿﺪ ﻓﻼك )FV( ﺗﺎ ﭘﺎ ﯾﺎن آزﻣﺎﯾﺶ دﯾﺪه ﺷﺪ و در ﺗﯿﻤﺎر 20 ﺑ ﯿﺸﺘﺮ ﺑﻮدﻧﺪ )0/05>p(. در ﭘﺎﯾﺎن آزﻣﺎﯾﺶ، ﻣﻘﺪار ECﺑﻪ ﺗﺮﺗﯿﺐ در ﺗﯿﻤﺎرﻫﺎي 10، 15و 20 ﺑﻪ ﺗﺮﺗﯿﺐ 1327/50 ، 1419/83و 1419/83 ﻣﯿﻠﯽﻣﻮس ﺑﺮ ﺳﺎﻧﺘﯿﻤﺘﺮ، ﺗﻮﻟﯿﺪ ﻓﻼك ﺑﻪ ﺗﺮﺗﯿﺐ71 mL/L ، 143/11و 163، ﻣﻘﺪار ﺑﯿﻮﻓﻼك ﺑﻪ ﺗﺮﺗﯿﺐ71 mL/L ، 143و 163 رﺳﯿﺪ. ﻧﺘﺎﯾﺞ اﯾﻦ آزﻣﺎﯾﺶ ﻧﺸﺎن داد ﮐﻪ در ﺑﮑﺎرﮔﯿﺮي ﻣﻼس ﺑﺮاي ﺗﻨﻈﯿ ﻢ ﻧﺴﺒﺖ ﮐﺮﺑﻦ ﺑﻪ ﻧﯿﺘﺮوژن، ﻧﺴﺒﺖ 20ﺷﺮاﯾﻂ ﺑﻬﺘﺮي را ﺑﺮاي رﺷﺪ ﻣﺎﻫﯽ ﮐﭙﻮر، ﺷﺮاﯾﻂ ﮐﯿﻔﯽ آب و ﺗﻮﻟﯿﺪ رﺷﺘﻪ ﻫﺎي زﯾﺴﺘﯽ در ﺳﺎﻣﺎﻧﻪ ﺑﺪون ﺗﻌﻮﯾﺾ آب اﯾﺠﺎد ﻣﯽ ﮐﻨﺪ.

The Bio-Floc has more efficacies compared to fixed Bio-film for removing the nitrogen compounds in water recirculating fish culture system. In this trial, a completely randomized experimental design was run to evaluate the roles of three different ratios of carbon to nitrogen (C:N) including 10 (treatment 10 = T10), 15 (T15) and 20 (T20), into the carp culture systems on growth and water quality. The mean individual weight was significantly higher in T20 compared to the other treatments. At the end of the experiment, the fish attained from 70 to 552.8, 704.7 and 708.8 g in T10, T15 and T20, respectively. The FCR, ammonia and nitrate concentrations were significantly higher in T10 compared to the other treatments (p<0.05). Concentration of ammonia in T10, T15 and T20 were 78, 29.9 and 29.9 mg/L, respectively. A depletion trend was recorded in pH in all treatments during the experimental period. The electrical conductivity (EC) and Bio-Floc formation rate increased in all treatments and was significantly higher in T20. The EC of water were 1327.5, 1419.83 and 1419.83 mmos/cm in T10, T15 and T20, respectively. The rates of Bio-Floc reached to 71, 143, 163 mL/L in T10, T15 and T20, respectively. The results of this experiment indicated that using molasses to adjust C:N ratio of water at 20, enhances formation of Bio-Floc, carp growth rate and water quality in a zero-exchange water system