In ovo feeding of organic salts of zinc and copper: effects on growth performance and health status of two strains of broiler chickens
Keywords:In ovo feeding, organic trace minerals, growth performance, Arbor Acre, Cobb 500, gut morphology, blood profile
Feeding of the embryo before hatch by in ovo administration of exogenous feed components has been reported to jump start growth and improve immune response in poultry. This study consisted of two experiments to determine the response of Arbor Acre strain of broiler chickens to in ovo injection of organic salts of zinc, copper and their combination in Experiment 1 while in Experiment 2, the response of Cobb 500 strain of broiler chickens to organic salts of zinc, copper and their combination was investigated. A total of 300 hatching eggs of Arbor Acre strain of broiler chickens were used for Experiment 1. After candling the eggs on the 14th day of incubation, 148 (59.2%) eggs were fertile. These eggs were distributed into four treatments: control (no in ovo supplementation), in ovo administration of organic zinc (80 μg/egg), organic copper (16 μg/egg) and combined organic zinc (80 μg/egg) and organic copper (16 μg/egg). In Experiment 2, 300 hatching eggs of Cobb 500 strain of broiler chickens were used. On 14th day of incubation, the eggs were candled and 232 (90.3%) eggs were fertile. The eggs were assigned into four treatment groups as in Experiment 1. In ovo injection of eggs was carried out on the 18th day of incubation in both experiments. Hatched chicks, 46 (31% hatchability); 191 (82% hatchability) in Experiments 1 and 2, respectively from each treatment were balanced for weight and the post-hatch response to in ovo injection of organic salts of zinc, copper and their combination was studied for 7 and 5 weeks in Experiments 1 and 2, respectively. Data collected were subjected to analysis of variance in a completely randomised design. Results in Experiment 1 indicated that hatchability was highest (P ≤ 0.05) in eggs on in ovo injection of combination of organic zinc and copper while humoral immunity to sheep red blood cell was highest (P ≤ 0.05) in birds from eggs on in ovo injection of organic zinc. Humoral immunity was improved (P ≤ 0.05) by in ovo injection of copper while cell-mediated immunity was also improved (P ≤ 0.05) by in ovo injection of organic zinc in Experiment 2. Growth performance was not significantly (P > 0.05) affected by the treatments in both Experiments 1 and 2. The haemoglobin and mean corpuscular haemoglobin were significantly (P ≤ 0.05) influenced by in ovo injection of both organic zinc and copper on day 7 in Experiment 2. The study concluded that in ovo injection of organic salts of zinc at 80 μg/egg and/or copper at 16 μg/egg should be adopted to improve immune response in both Arbor Acre and Cobb 500 strains of broiler chickens.