Effect of source and concentration of zinc on growth performance, meat quality and mineral retention in New Zealand rabbits

Zinc supplementation in rabbit diet favours deposition of this mineral in meat and, therefore, contributes to satisfying the daily requirements of Zn in humans that consume it. A trial was conducted to study the effect of two sources (ZnSO4 and Zn-methionate) and two concentrations of Zn, along with a control (without Zn supplementation), on weight gain, meat quality and muscle retention in New Zealand White (NZW) rabbits during fattening stage. Treatments were randomly assigned to 100 NZW rabbits 40 days old, in a completely randomised experimental design using a factorial arrangement of treatments (2×2+control). The experimental period was 30 d. In each experimental treatment, weight gain, feed consumption and meat quality were recorded, as well as the retention of Zn in serum, liver, loin and hind leg. Results showed no differences (P>0.05) in weight gain and food consumption, which can be attributed to diet-added Zn sources (ZnSO4 and Zn-methionate). Food conversion was better with the organic source at the highest concentration (P<0.05). Regarding meat quality, no differences were found (P>0.05) in hind legs for source effect and Zn concentration, while in loin, differences (P=0.02) were found in the colour parameter of L* and B* when the organic source of Zn (Zn-methionate) was supplied. Most retention of Zn on the loin occurred when a concentration of 25 mg Zn kg–1 of Zn-methionate was added, which could be important to provide larger amounts of Zn for human consumption.