Research Round-up on Feeding Broiler Breeders

Broiler breeders need to have their feed intake restricted in order to maintain egg production but this can make their feeding more challenging. Two recent scientific papers demonstrate the importance of trace mineral levels for the health of the progeny as well as the effects of different fibre sources on the hens' egg output.

3 November 2013

4 minute read

By: Jackie Linden

Broiler Immunity Affected by Parent Bird Feeding

Breeder feed restriction may negatively affect broiler progeny immunity, according to Dr Edgar Oviedo of North Carolina State University and co-authors there and at Brazil's Universidade Federal de Goiás and Universidade Estadual Paulista.

In a paper in Journal of Applied Poultry Research recently, they explained that sources of trace minerals with higher bioavailability in breeder diets have been reported to enhance humoral and cellular immunity in broiler progeny.

They conducted an experiment to examine the effects of breeder feeding programmes and trace mineral dietary sources on maternal antibody transfer and humoral immune response of progeny to a live vaccine against Newcastle disease.

Cobb 500 breeders were fed according to two feed allocation programmes - sigmoid late fast and sigmoid late slow - from 14 to 29 weeks of age. From 56 to 62 weeks of age, breeders were fed with either inorganic trace minerals or an organic source (OTM) to replace 30 per cent of copper, zinc and manganese.

Progeny broilers were vaccinated intraocularly with La Sota NDV vaccine at seven days of age. Blood samples were collected at hatching and four and 14 days post-vaccination. Serum antibody levels against NDV were assessed by ELISA and cytokine expression by real time PCR.

At hatching, late slow breeder progeny fed diets with 30 per cent OTM had higher antibody titres than progeny of breeders fed 100 per cent inorganic trace minerals. Similar results were observed two weeks post-vaccination.

The researchers found that breeder feeding programme and trace mineral source affected the expression level of IL-4 in Newcastle disease vaccinated broiler progeny.

Oviedo and co-authors concluded that breeder feeding programmes influenced humoral immune response to Newcastle disease vaccine in the broiler progeny, and 30 per cent OTM may increase these responses.

Diets High in Insoluble Fibre Improve Broiler Breeder Hen Reproduction

To alleviate the feeling of hunger in broiler breeder hens, different types of fibre sources were used by S. Moradi of the University of Tehran and co-authors there and at the Agriculture Biotechnology Research Institute of Iran. Their paper has recently been published in Journal of Applied Poultry Research.

They explain that the fibre sources were used to increase feed allowance for Cobb 500 broiler breeder hens from 24 to 38 weeks of age.

Dietary treatments were a control diet and low-density diets through inclusion of wheat bran (WB), cellulose (CEL), pectin and cottonseed meal. All diets had the same content of Apparent Metabolisable Energy, crude protein, calcium, phosphorus and amino acids.

Providing a diet with insoluble and soluble fibre sources increased the duration of feeding 2.4 and 3.8 times more than control group, respectively.

For the entire experimental period, proportion of insoluble fibre sources (CEL and WB) resulted in higher egg production than the control group.

Cottonseed meal-fed birds had higher concentrations of triacylglycerol and cholesterol in the plasma and heavier abdominal fat pads.

Inclusion of insoluble fibre sources (CEL and WB) significantly decreased plasma corticosterone concentration, which is an indicator of hunger and frustration in birds.

In spite of equal total nutrient intakes once laying commenced, Moradi and co-authors commented that providing high-fibre diets with insoluble fibre sources improved the reproductive performance of broiler breeder hens in the early part of the production period.