Ameliorative effects of vitamin C (L-ascorbyl-2-polyphosphate) on growth, survival rate, feed conversion ratio, coefficient of variation, and hematology of juvenile snubnose pompano Trachinotus blochii (Lacepède, 1801)

Abstract

This study sought to determine the effects of vitamin C added to feed on the growth (daily growth rate in length - DLG; weight - DWG; specific growth rate in length - SGRL, and weight - SGRW)survival rate (SR), feed conversion ratio (FCR), coefficient of variation (CV), and hematology of juvenile snubnose pompano (Trachinotus blochii). Five levels of vitamin C (VC), including 0, 150, 300, 450, and 600 mg VC kg-1, were supplemented to the control diet. Each treatment was repeated 3 times in marine cages (1×1×1 m) at a density of 30 fish per cage. After eight weeks of experiment, the results showed that there were significant differences in the growth parameters of fish (p<0.05) among the VC treatments. Daily growth rate, relative growth rate, and specific growth rate in terms of length and weight were highest in the treatment with 450 mg VC kg-1 of feed and lowest in the control treatment(p<0.05). However, the experiment showed that the added VC to the feed did not affect the SR of snubnose pompano (p>0.05). The FCR values were substantially reduced in fish fed diets supplemented with all VC levels (p<0.05). Fish on a diet featuring 150 or 450 mg VC kg-1 had substantially lower values of coeficiency of variantion in weight (CVW) (p<0.05), whereas the addition of 300 or 600 mg VC kg-1 increased the CVW values (p<0.05). Moreover, the addition of VC to the diet substantially increased hematological parameters, such as red blood cell (RBC), white blood cell (WBC), hemoglobin (Hb), hematocrit (Ht), and serum protein (p<0.05), whereas there was no difference in mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC) among treatments (p>0.05). Thus, dietary vitamin C positively influenced growth and hematological parameters in snubnose pompano in the 450 mg VC kg-1 of feed treatment.