Dietary copper requirement of juvenile yellow catfish Pelteobagrus fulvidraco

Abstract

The present experiment was conducted to quantify dietary copper (Cu) requirement for juvenile yellow catfish Pelteobagrus fulvidraco. The six experimental diets were formulated to contain the graded levels of CuSO4·5H2O (0, 0.005, 0.01, 0.02, 0.04 and 0.08 g kg−1 diet respectively) providing the actual dietary copper values of 2.14 (control), 3.24, 4.57, 7.06, 12.22 and 22.25 mg Cu kg−1 diet respectively. Each diet was fed to triplicate groups of yellow catfish (initial body weight: 3.13 ± 0.09 g, means ± SD) in an indoor static rearing system for 7 weeks. Fish fed the diet containing 3.24 mg Cu kg−1 diet had the highest weight gain and specific growth rate, but they were not significantly different from that of fish fed the 4.57 and 7.06 mg Cu kg−1 diets (P > 0.05). The poorest feed conversion rate, the lowest protein efficiency ratio, the lowest hepatosomatic index and viscerosomatic index were observed in fish fed the diet containing the highest Cu content diet (P < 0.05). Condition factor showed no significant differences among the treatments (P > 0.05). Proximate composition of fish body was significantly affected by dietary copper level (P < 0.05). Cu contents of whole body and liver increased with dietary Cu levels (P < 0.05), but muscle Cu content remained relatively stable (P > 0.05). Analysis by the second‐order regression of SGR and linear regression of whole‐body Cu retention of the fish indicated that dietary Cu requirements in juvenile yellow catfish were 3.13–4.24 mg Cu kg−1 diet.

Differential effects of dietary copper deficiency and excess on lipid metabolism in yellow catfish Pelteobagrus fulvidraco

“…In the present study, fish were fed the Cu deficient diet produced a slower growth rate than the adequate Cu diet, in agreement with several reports (Ogino and Yang, 1980;Lin et al, 2008;Tan et al, 2011), indicating that Cu content in the rearing water could not meet the requirements of fish and therefore dietary supplementation was necessary. However, dietary Cu excess also resulted in growth retardation, in agreement with other reports (Kim and Kang, 2004;Shaw and Handy, 2006;Lin et al, 2008;Tan et al, 2011).…”

“…At present, optimal dietary Cu requirement has been determined in many fish species, ranging from 3 to 10 mg Cu kg − 1 feed, which depends on the species, feeding regime and life stage (Clearwater et al, 2002;NRC, 2011). Studies have also shown that over-loading of dietary Cu in fish caused toxic syndrome (Handy, 1996;Berntssen et al, 1999a;Lundebye et al, 1999;Shiau and Ning, 2003), including reduced growth (Clearwater et al, 2002;Shaw and Handy, 2006;Tan et al, 2011), severe lesions in the gut (Handy, 1996), and subtle changes in intestinal cell proliferation and turnover (Berntssen et al, 1999a;Lundebye et al, 1999). In contrast, dietary Cu deficiency has been shown to reduce appetite, growth and cause anemia in several fish (Ogino and Yang, 1980;Gatlin and Wilson, 1986;Shiau and Ning, 2003;Lin et al, 2008;Tan et al, 2011).…”

“…Different Cu contents were added to the diets, based on our recent study , in order to produce three different dietary Cu groups (Cu deficiency, adequate Cu and Cu excess, respectively). The formulation of the experimental diets was according to Tan et al (2011). The formulated diets were dried at 80°C in an oven until the moisture was reduced to less than 10%.…”

“…In fish, studies have also demonstrated that variations in dietary Cu levels have a profound effect on lipid deposition. For example, elevated dietary Cu concentrations reduced whole-body lipid content (Berntssen et al, 1999b;Tan et al, 2011). Meanwhile, by histological observation, liver sections from dietary Cu-exposed fish exhibited abnormal lipid deposition in the hepatocytes (Handy et al, 1999;Shaw and Handy, 2006).…”

Dietary manganese requirement of juvenile yellow catfish Pelteobagrus fulvidraco, and effects on whole body mineral composition and hepatic intermediary metabolism

“…At present, different parameters have been used to determine mineral requirement in fish, including growth performance (Lin et al, 2010;Pan et al, 2008;Tan et al, 2011), feed utilization (Luo et al, 2010, tissue mineral concentration (Lin et al, 2008;Luo et al, 2010;Maage et al, 2000;Pan et al, 2008;Tan et al, 2011) and hepatic Mn-SOD activity (Lin et al, 2008). Our present study indicated that Mn requirements obtained from WG, PER and hepatic Mn-SOD activities were similar, whose values were 5.5, 5.6 and 6.4 mg kg − 1 diet, respectively.…”