The Promise and Challenges of Determining Recombinant Bovine Growth Hormone in Milk

Abstract

Recombinant bovine growth hormone (rbGH) is produced in large quantities and widely used in a number of countries worldwide to stimulate milk production in dairy animals. The use of this compound in animal production is strictly regulated by food safety directives in force, in particular in the European Union (EU). Although analytical strategies for the detection of rbGH in blood have been successfully reported over the past 15 years, they do not fully answer the expectations of either competent authorities or industrials that would expect measuring its occurrence directly in the milk. As a matrix of excretion but also of consumption, milk appears indeed as the matrix of choice for detecting the use of rbGH in dairy animals. It also allows large volumes to be collected without presenting an invasive character for the animal. However, rbGH detection in milk presents several challenges, mainly related to the sensitivity required for its detection in a complex biological matrix. This review article presents the specific difficulties associated with milk and provides an overview of the analytical strategies reported in the literature and whether they concern indirect or direct approaches to the detection of rbGH administration to animals, with applications either for screening or confirmation purposes.

Impact of Recombinant Bovine Somatotropin on Bovine Milk Composition and Fatty Acidome: A Multidose Longitudinal Study

“…Milk is an undoubtedly useful matrix that can be easily collected daily, even twice a day, it is non-invasive, rich in fat, and sample processing is minimal. As such, it has already been pointed out as an ideal target sample for rbST monitoring [ 32 ]. However, it should be noted that fatty acids are involved in many biological processes and are influenced by many factors that cannot be controlled, so their profiles cannot be used for confirmation and must be considered carefully in the omics era.…”

“…This approach is focused on detecting the tryptic N-terminal peptide, specific to the recombinant methionine-rbST form. Nonetheless, the limitations of using milk are well-known [ 32 ] and blood analysis by LC-MS/MS is recommended for enforcement purposes, in combination with screening strategies [ 9 , 34 ]. Plus, mass spectrometry enables the identification of alanine-rbST (Ala-rbST, identical to endogenous bST) and methionine-rbST (Met-rbST) variants.…”