Etseoghena Obi | ALES Graduate Seminar

Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Etseoghena Obi. This seminar is open to the general public to attend.

MSc with Dr Martin Zuidhof. 

Thesis Topic: Effect of maternal feeding level and growth patterns on broiler performance using a precision feeding system

Abstract: 

Broiler breeders, the parent stock of broilers (meat-type chicken), are subjected to feed restriction, while their offspring, broilers, are provided with ad libitum feeding under the current broiler production system. While most research on improving broiler performance has focused on post-hatch factors like broiler nutrition, pre-lay or maternal factors such as maternal feed intake and growth, also demonstrate lasting effects on broiler performance. Broiler breeder environment transfers both genetic and non-genetic information to offspring, influencing embryonic development and subsequent offspring performance. Maternal growth plays a key role in transmitting this information from mother to offspring in broiler production.

The aim of this thesis was to investigate the effect of broiler breeder management on offspring performance. More specifically, target body weight (BW) was used to influence nutrient uptake to cause a change in maternal feeding level and maternal growth patterns. Effects of these maternal interventions were investigated on egg weight, chick weight and broiler offspring performance. It was hypothesized that ad libitum feeding of broiler breeders would increase egg and chick weights, broiler offspring BW, cumulative feed conversion ratio (FCR), breast muscle, and abdominal fat pad yields. It was also hypothesized that earlier broiler breeder pubertal inflection point and increased pre-pubertal BW gain (created by modifications to some coefficients of multiphasic Gompertz growth model) would increase egg and chick hatch weights, broiler offspring BW, breast muscle and abdominal fat pad yields, and decrease broiler cumulative FCR. It was further hypothesized that egg weight, broiler BW, and breast yield would increase whereas FCR and abdominal fat pad yield would decrease as breeder age increased. Two studies were conducted to challenge these hypotheses.

The first study had a 2 × 2 × 3 factorial arrangement of treatments, which included two maternal feeding treatments, two sexes and three maternal ages. Using a precision feeding system, female Ross 308 broiler breeders were either fed ad libitum (that is, meal every visit (MEV)) or restricted (STD) based on the breeder-recommended target BW from 0 to 59 weeks (wk) of age. Broiler offspring experiments were conducted at each of 32, 42, and 52 wk of broiler breeder age. Broilers from MEV breeders had a heavier breast yield than those from feed-restricted breeders.

In the second study, various broiler breeder BW trajectories were derived by changing coefficients of a 3-phase Gompertz growth model that estimated pre-pubertal (early), pubertal and post-pubertal phases of growth. A 6 × 2 factorial arrangement of growth treatments was applied to precision-fed Ross 308 broiler breeders, with six levels of maternal pubertal inflection point (Mat I2): 15, 17, 19, 21 (control), 22 and 23 wk of age; and two levels of Maternal early gain (Mat EG): shifting 0 (EG0: control) or 20% (EG20) of pubertal gain (g₂) to the early growth phase (g₁). Broiler offspring experiments were also conducted at each of 32, 42, and 52 wk of broiler breeder age. In the 21-wk Mat I2 treatment, Mat EG20 broilers were heavier than Mat EG0 broilers, indicating that increasing early gain in broiler breeders increased the growth rate in offspring. Broilers from the 23-wk Mat I2 treatment were less feed efficient than broilers from 19- and 21-wk Mat I2 treatments, respectively. In the Mat EG0 treatment, broilers from the 19-wk Mat I2 treatment had greater breast weight than those from the 21-wk Mat I2 treatment. The effect of maternal age on broiler performance in both studies was consistent with the hypothesis. In summary, modifying broiler breeder growth patterns offers a strategy to improve offspring performance and optimize broiler productivity.