Pyrroloquinoline quinone supplemented diet enhances metabolism, feed intake and growth in common carp (Cyprinus carpio Linnaeus, 1758) reared at low temperature

A pilot study was conducted to delineate the potential of dietary pyrroloquinoline quinone (PQQ) on Cyprinus carpio Linnaeus, 1758, at water temperature of 12-14 degrees C using a recirculatory system with water flow rate of 1.8 l min(-1). Six isonitrogenous (32% CP) and iso-caloric (16.7 MJ kg(-1)) diets were prepared with varying levels of PQQ viz. control (0 mg kg(-1)), T1 (0.2 mg kg(-1)), T2 (0.4 mg kg(-1)), T3 (0.6 mg kg(-1)), T4 (0.8 mg kg(-1)) and T5 (1.0 mg kg(-1)). Two hundred and sixteen common carp juveniles were distributed randomly into control and five treatment groups in triplicates with 12 fish per tub and fed twice daily at satiation level for 30 days. Results indicated that dietary quinone at 0.8 mg kg(-1) significantly (p<0.05) increased the feed intake and weight gain, specific growth rate (SGR), feed conversion ratio (FCR) as well as protein efficiency ratio (PER). The thyroid hormone levels as well as digestive and metabolic enzyme activities were significantly higher (p<0.05) in treatments than in control. The superoxide dismutase (SOD) activity in liver was significantly higher (p<0.05) in T1, T2 and T5. Catalase activity in gill was significantly higher (p<0.05) in control and lowest in T3 and T4. Therefore, quinone can be used as a feed additive for enhancing feed intake, enzymatic activities and growth during winter.