Effect of dietary amounts of inorganic and organic zinc on productive and physiological traits of White Pekin ducks.

The effects of different dietary amounts of organic and inorganic Zn were studied in male White Pekin ducks (WPD) from 1 to 56 days of age. The control diet (26 ppm of Zn from raw ingredients) was supplemented with 30, 60 and 120 ppm of Zn from both inorganic and organic sources, for a total of seven treatment groups, each containing five replicates of nine 1-day-old ducklings each. BW, feed intake and feed conversion ratio (FCR) were recorded at 1, 28 and 56 days of age. At 56 days of age, five birds per group were used in a digestibility trial to measure Zn retention and excretion. At the end of the trial, five birds per treatment were slaughtered and carcass traits as well as Zn content in tibia and liver were measured. Samples of blood from five birds per treatment were used to measure plasma concentration of Zn and Cu. BW gain during the entire period of the trial increased (P < 0.001) by 30 and 60 ppm of Zn. Increasing Zn contents progressively increased (P < 0.001) the tibia and the liver Zn contents as well as the plasma Zn and Cu contents. The concentration of 120 ppm of Zn increased (P < 0.001) tibia ash and decreased (P < 0.001) abdominal fat in the carcasses. In the period 1 to 56 days, Zn oxide increased (P < 0.001) growth rate and improved (P < 0.03) FCR compared with organic Zn, whereas organic Zn increased (P < 0.003) the dressed carcass percentage. Organic Zinc increased (P < 0.001) Zn and Cu concentration in the plasma. A level of 30 ppm of Zn from an inorganic source was adequate for male WPD during 1 to 56 days of age, based on positive effects of growth rate and Zn excretion.

Effect of different dietary concentrations of inorganic and organic copper on growth performance and lipid metabolism of White Pekin male ducks.

1. The effect of different dietary concentrations of inorganic and organic copper on performance and lipid metabolism of White Pekin ducks (WPD) was investigated from 1-49 d of age. A common basal diet was supplemented with 4, 8, 12 and 150 mg/kg of copper (Cu) from inorganic and organic sources to obtain 9 treatments, including 4 concentrations of Cu x two sources, and the unsupplemented control group. Each treatment contained 5 replicates of 9 male ducks each. 2. Supplementation of Cu at 8 mg/kg in inorganic form was adequate for growth of male WPD from 1-56 d of age. Inorganic Cu significantly decreased feed intake and improved feed conversion ratio, compared with the organic form. 3. Plasma Cu significantly increased, while plasma Zn significantly decreased, due to Cu supplementation. Organic Cu showed better efficacy than inorganic for improving liver Cu concentration, Cu excretion and apparent Cu retention. 4. Dietary Cu concentration significantly affected percentage blood and Hgb and abdominal fat deposition. In addition, inorganic Cu increased percentage blood and abdominal fat deposition compared with the organic source. 5. Supplementation of 150 mg/kg of Cu significantly decreased liver and meat lipids, cholesterol, and colour and tenderness of meat; while liver protein and moisture was increased. In addition, dietary 150 mg/kg of Cu supplementation significantly decreased plasma lipids, triglycerides and cholesterol, while increasing plasma AST and ALT. 6. Organic Cu was more potent for decreasing plasma triglycerides than the inorganic source. However, plasma cholesterol was only significantly decreased with the inorganic source of Cu, compared with the unsupplemented control. 7. The organic Cu was safer as a feed additive for WPD, especially at the lower concentrations up to 12 mg; while some mild to moderate changes may be developed at the higher doses, when fed at pharmacological concentrations as a growth promoter.