1.Tianjin Enterprise Key Laboratory of Functional Feed of Aquatic Animals, Tianjin Chenhui Feed Company Limited, Tianjin 301800, China; 2.College of Fisheries, Tianjin Key Laboratory of Aqua-Ecology and Aquaculture, Tianjin Agricultural University, Tianjin 300384, China
Abstract: A 56 day feeding trial was conducted to evaluate the effects of dietary folic acid and vitamin B12(VB12) levels on growth performance and immunity of yellow catfishPelteobagrusfulvidraco by determination of body weight, weight gain rate (WGR), specific growth rate (SGR), food conversion ratio (FCR), complement C3, complement C4， and nitric oxide (NO) levels, and activity of nitric oxide synthase (NOS). A total 900 individuals of yellow catfish with initial body weight of (31.84±0.05)g were randomly divided into ten groups, and fed diets containing 0%, 0.15%, 0.30%, and 0.45% of folic acid and 0%, 0.05%, 0.10%, and 0.15% of VB12 with 3×3 factorial design with triplication. The final body weight, WGR, and SGR were found to be increased and FCR was found to be decreased with increase in levels of folic acid and VB12, the maximal SGR, WGR, and SGR and the minimal FCR in the fish fed the diet containing 0.45% of folic acid/0.15% of VB12, significantly different from those in the control group(P<0.05). There were the maximal contents of complement C3, and complement C4, and NO and NOS activity in the serum and liver of yellow catfish fed the diet containing 0.45% of folic acid/0.15% of VB12, significantly different from those in other groups (P<0.05). The findings indicate that the appropriate amounts of dietary folic acid and VB12 effectively promote the growth and immunity of yellow catfish. It is recommended that 0.45% of folic acid/0.10% of VB12 be the appropriate dose for improvement of growth and immunity of yellow catfish.
2018, Vol. 33 
