تاثير سطوح مختلف پروتئين بر شاخص هاي رشد بچه ماهي كپور معمولي (Cyprinus carpio) در سيستم پرورش متراكم

Effects of different protein levels on growth indices of common carp (Cyprinus carpio) fingerling in the intensive culture system

ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ ﺑﻪ ﻣﻨﻈﻮر ﺑﺮرﺳﯽ ﺗﺄﺛﯿﺮ ﺳﻄﻮح ﻣﺨﺘﻠﻒ ﭘﺮوﺗﺌﯿﻦ ﺟﯿﺮه ﻏﺬاﯾﯽ ﺑﺮ ﺷﺎﺧﺺﻫﺎي رﺷﺪ ﺑﭽﻪ ﻣﺎﻫﯽ ﮐﭙﻮر ﻣﻌﻤﻮﻟﯽ در ﮐﺎرﮔﺎه ﭘﺮورش ﻣﺘﺮاﮐﻢ و در 15 ﺣﻮﺿﭽﻪ ﻣﺮﺑﻊ ﺷﮑﻞ ﻓﺎﯾﺒﺮﮔﻼس )اﺑﻌﺎد 2 × 2× 0/5ﻣﺘﺮ( در 5 ﺗﯿﻤﺎر و ﺳﻪ ﺗﮑﺮار ﺑﺮ اﺳﺎس ﻣﺤﺘﻮاي 22/29،24 /33 ،26/15 ، 28/32 و30/31 % ﭘﺮوﺗﺌﯿﻦ ﺧﺎم ﺟﯿﺮه ﻃﯽ 60 روز در داﻣﻨﻪ دﻣﺎي آب 22-31 درﺟﻪ ﺳﺎﻧﺘﯽﮔﺮاد و داﻣﻨﻪ اﮐﺴﯿﮋن ﻣﺤﻠﻮل 5/1-7/3ﻣﯿﻠﯽﮔﺮم ﺑﺮ ﻟﯿﺘﺮ اﻧﺠﺎم ﺷﺪ ﺗﺎ ﻋﻤﻠﮑﺮد ﺑﻬﯿﻨﻪ رﺷﺪ ﺑﺮاي ﺑﻬﺘﺮﯾﻦ ﺟﯿﺮه ﻣﻌﯿﻦ ﺷﻮد. ﻫﺮ ﺣﻮﺿﭽﻪ ﺑﺎ 250 ﻗﻄﻌﻪ ﺑﭽﻪ ﻣﺎﻫﯽ ﺑﺎ ﻣﯿﺎﻧﮕﯿﻦ وزن ﺑﺪن 0/66 ± 4 ﮔﺮم ﻣﺎﻫﯽدار ﺷﺪﻧﺪ . ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﺑﭽﻪ ﻣﺎﻫﯿﺎﻧﯽ ﮐﻪ از ﺟﯿﺮهﻫﺎي ﺑﺎ ﺳﻄﻮح ﭘﺮوﺗﺌﯿﻨﯽ 26/15 و28/32 % ﺗﻐﺬﯾﻪ ﺷﺪﻧﺪ، داراي ﺑﺎﻻﺗﺮﯾﻦ اﻓﺰاﯾﺶ وزن ﺑﺪن، ﺿﺮﯾﺐ رﺷﺪ وﯾﮋه، درﺻﺪ اﻓﺰاﯾﺶ وزن ﺑﺪن و ﺑﺎزده ﭘﺮوﺗﺌﯿﻨﯽ ﺑﻮدﻧﺪ )0/05>p(. ﻫﻤﭽﻨﯿﻦ ﻣﯿﺰان ﺿﺮﯾﺐ ﺗﺒﺪﯾﻞ اﯾﻦ دو ﺟﯿﺮه ﻧﯿﺰ ﻧﺴﺒﺖ ﺑﻪ دﯾﮕﺮ ﺟﯿﺮهﻫﺎ ﮐﺎﻫﺶ ﻣﻌﻨﯽ داري داﺷﺖ )0/05>p(. ﻣﯿﺰان ﺿﺮﯾﺐ ﭼﺎﻗﯽ و درﺻﺪ ﺑﺎزﻣﺎﻧﺪﮔﯽ در ﺗﻤﺎﻣﯽ ﺗﯿﻤﺎرﻫﺎ ﯾﮑﺴﺎن ﺑﻮد )0/05

The present study examined the effects of different protein concentrations on growth of juvenile common carp kept in 15 fiberglass ponds (0.5 × 2 × 2 m) under intensive culture system involving 5 treatments and 3 replications, based on the following raw protein contents (24.22, 26.15, 28.32, 30.31, 33.29%) included in the fish diet for a period of 60 days and with a water temperature ranging 22-31oC, and dissolve oxygen level of 5.1-7.3 mg/L to determine diet formulation ensuring an optimum growth performance. Each rearing pond was introduced with 250 pieces of juvenile fish (4 ± 0.66 g) amounting to an average of 1 kg fish biomass. The results indicated that juveniles receiving protein levels of 28.32% and 26.15% had the highest body weight, specific growth rate, weight gain percentage and protein yields (p≤0.05). In addition, the feed conversion ratio related to these two diets showed significant decline (p≤0.05). The condition factor and survival rate remained the same across all treatments (p≥0.05). The study revealed that the protein increment ratio of up to 28.15% in the diet contributed to the increased growth indices among juvenile common carp and concentrations beyond that did not lead to any effective increase in fish growth.