Does the Type of Semen Affect the Phosphoproteome of Turkey (Meleagris gallopavo) Spermatozoa?

Yellow semen syndrome (YSS) is an increasingly common reproductive health problem in male turkeys. This condition is characterised by a yellow discolouration of semen, often linked to decreased semen quality and fertility. Yellow semen syndrome poses a significant concern due to its negative impact on the reproductive performance of turkeys. Phosphorylation is one of the major post-translational modifications of proteins. A better understanding of the function of the sperm phosphoproteome is crucial for the advancement of reproductive biology and the development of therapies for male infertility. Spermatozoa from semen samples with YSS were characterised by lower levels of malondialdehyde (MDA), reduced plasma membrane integrity (PMI), and decreased mitochondrial membrane potential (MMP). However, these samples showed increased antioxidant enzyme activity and an elevated glutathione (GSH) content. Yellow sperm also had a lower percentage of viable cells and a higher proportion of apoptotic and necrotic cells. The phosphoproteins identified in turkey sperm play key roles in sperm maturation, the development of a functional motility apparatus, efficient cellular metabolism, protection against oxidative stress, and successful fertilisation of an egg. Yellow semen syndrome altered the phosphorylation of turkey sperm proteins on serine, threonine (<i>p</i> ≤ 0.05), and tyrosine residues, which could have influenced the metabolism and physiology of spermatozoa in yellow semen samples, thus affecting their reproductive potential. These findings highlight the impact of YSS on sperm function, including phosphorylation-dependent processes that are crucial for reproduction.