Chelated Trace Minerals Improve Pullet Flock Uniformity and Egg Performance During Early Lay

Minerals such as copper, manganese and zinc are essential nutrients for enzyme functionality, immune system responses, tissue and bone quality as well as eggshell formation (Richards et al., 2010). Organic trace minerals are used in animal feeds to provide increased mineral bioavailability. In this experiment we investigated the benefits of hydroxy analogues of chelated trace minerals on pullet quality. Three hundred- and sixty day-old Isa Brown layers were randomly allocated into two groups with nine replicates per treatment and twenty pullets per replicate. The control group received standard diets (starter, grower, developer and layer) meeting the nutrient requirements outlined in the breeder manual. The treatment group received same isonitrogenous and isocaloric diets but the conventional zinc, copper and manganese levels were replaced (using 33.3% less chelated trace mineral hydroxy analogues) with 40 ppm chelated zinc, 10 ppm chelated copper and 40 ppm chelated manganese. Weekly feed intake, weekly body weight, average daily gain and feed conversion ratio of pullets for each pen were measured until 22 weeks of age. The flock uniformity was measured at 1, 4, 12 and 22 weeks of age. At 12 and 22 weeks of age, four pullets per pen were randomly selected and humanely killed to evaluate tibia bone quality, blood haematology profile, intraepithelial lymphocytes, oviduct development and CT scanned to determine carcass composition. Pullets experienced comparable growth performance, bone quality and immune status. The tibia bone weight of the treatment group at 12 weeks of age was significantly higher (P = 0.037) compared to the control group, but no difference was observed on further investigation of mineral content and morphometric parameters. The egg mass of the treatment group (34.0 g/hen/day) was significantly higher (P = 0.002) at 20 weeks of age compared to the control group (30.8 g/hen/day) while egg size remained comparable. Laying rate was significantly higher (P = 0.002) for hens fed with chelated trace minerals at week 20 (71.6 ± 2.54%) and week 22 (94.9 ± 1.07%) compared to the control group (65.9 ± 2.06% and 87.4 ± 2.04%, respectively). A trend of higher total bone weight (202 ± 3.76 g vs 188 ± 2.83 g) and bone ash weight (161 ± 1.98 g vs 151 ± 2.23 g) was observed in the birds fed the chelated minerals (P = 0.081). In addition, flock uniformity of the chelated mineral fed hens was 10% higher at 22 weeks of age (P 0.008) when compared to the control group hens. The average live weights (g) and flock uniformity (%) at 22 weeks of age were 1773.2 ± 68.8; 84.0% and 1699.5 ± 59.9; 93.8% for control and treatment groups, respectively. The breed standard for live weight at 22 weeks is 1713g. This higher flock uniformity allows for a more appropriate physiological state to support long-term hen productivity as well as skeletal and egg quality. In conclusion, the addition of chelated trace minerals might be beneficial in improving flock uniformity and improving egg output, therefore supporting hen health and productivity during later stages of hen’s life cycle.

ACKNOWLEDGEMENT: NOVUS and Poultry Hub Australia provided financial and administrative support for this research.