Plasma metabolomic profiling reveals potential onset of lay biomarkers in broiler breeders

M. Afrouziyeh, N. M. Zukiwsky, D.R. Korver, M. J. Zuidhof. Plasma metabolomic profiling reveals potential onset of lay biomarkers in broiler breeders, Poultry Science, Volume 101, Issue 1, 2022, 101532, ISSN 0032-5791, https://doi.org/10.1016/j.psj.2021.101532

broiler breeder, metabolomics, peer-reviewed, Publication, Research Showcase 2022, sexual maturity

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Broiler breeder pullets need to reach a certain metabolic status to achieve sexual maturation at photostimulation. Variations in nutrient intake and subsequent energy status are communicated to the liver and hypothalamic-pituitary axis by alterations in the plasma levels of hormones. Reproductive system maturation and changes in some plasma metabolites and reproductive hormones occur during the pullet-to-hen transition period. Profiling the plasma metabolome may provide a new perspective for studying the metabolic response of sexual maturity in breeders, a better understanding of its biological mechanisms, and potential biomarkers for predicting the onset of lay. The objectives of the current study were to evaluate the effect of lay status (pullet vs. hen), photostimulation BW, and onset of lay timing (early vs. late) on plasma metabolomic dynamics to identify potential biomarkers of
sexual development in broiler breeders.

Approach

A total of 36 pullets were used, in which 30 pullets were randomly assigned to one of 10 unique growth trajectories and 6 birds were assigned to an unrestricted group. The growth trajectories were designed using a 3-phase Gompertz growth model with 10 levels of BW gain in the prepubertal and pubertal growth phases ranging from the breeder-recommended target BW to 22.5% higher, in 2.5% increments. The BW trajectories were applied to each individual bird using a precision feeding (PF) system, which collected BW and feed intake data for each individual bird. The birds were classified based on age at first egg (AFE), and 12 pullets were chosen from the lower and upper AFE extremes (early and late onset of lay) at 18, 20, 22, 24, and 26 wk of age to run repeated blood plasma metabolomic assays.

Analysis of Results

Univariate analysis identified 87 differential metabolites between the early- and late-onset of lay groups at 24 wk of age and 104 differential metabolites between the pullet and hen groups. Further investigation of differential metabolites showed 15 potential biomarkers for
pullet to hen transition by analyzing the receiver operating characteristic (ROC) curve, mainly consisting of carnitine and choline metabolites. Differential metabolites during the pullet-to-hen transition were mainly associated with lipid, energy, and amino acid metabolism
pathways, which gave clues to the physiological and metabolic shifts resulting from sexual maturation. At 24 wk of age, the main pathways involved in differentiation of the early- and late-onset of lay groups were related to lipid and amino acid metabolism. These metabolites could be involved in biosynthesis of egg yolk precursors in the liver.

Application

In conclusion, this study indicated that metabolic transition during the onset of lay in broiler breeders is accompanied by certain metabolic signatures that can be used to predict the metabolic status linked to the bird’s maturity. More research is needed to reach the goal of designing a point-of-care device (similar to a portable blood glucometer) to measure broiler breeder plasma metabolome in real-time at the flock level and in a matter of seconds. Thereby, the poultry industry can use the extracted data to evaluate sexual development status in a flock.

Abstract

Changes in the metabolic fingerprint of plasma during the onset of lay in broiler breeders were investigated. We used metabolomics to identify biomarkers of sexual maturity and to provide a comprehensive understanding of breeder metabolome during the pullet to hen transition period. A total of 36 pullets were used, in which 30 pullets were randomly assigned to one of 10 unique growth trajectories and 6 birds were assigned to an unrestricted group. The growth trajectories were designed using a 3-phase Gompertz growth model with 10 levels of BW gain in the prepubertal and pubertal growth phases ranging from the breeder-recommended target BW to 22.5% higher, in 2.5% increments. The BW trajectories were applied to each individual bird using a precision feeding (PF) system, which collected BW and feed intake data for each individual bird. The birds were classified based on age at first egg (AFE), and 12 pullets were chosen from the lower and upper AFE extremes (early and late onset of lay) at 18, 20, 22, 24, and 26 wk of age to run repeated blood plasma metabolomic assays. The metabolomic profile data were collected using a direct-injection liquid chromatography-tandem mass spectrometry and steroid assays. Univariate analysis identified 87 differential metabolites between the early- and late-onset of lay groups at 24 wk of age and 104 differential metabolites between the pullet and hen groups. Further investigation of differential metabolites showed 15 potential biomarkers for pullet to hen transition by analyzing the receiver operating characteristic (ROC) curve, mainly consisting of carnitine and choline metabolites. Differential metabolites during the pullet to hen transition were mainly associated with lipid, energy, and amino acid metabolism pathways, which gave clues to the physiological and metabolic shifts resulting from sexual maturation. At 24 wk of age, the main pathways involved in differentiation of the early- and late-onset of lay groups were related to lipid and amino acid metabolism. These metabolites could be involved in biosynthesis of egg yolk precursors in the liver.