Identification of Protein and Lipid Biomarkers of Infertility in Young Boars and Prepubertal Gilts
Abstract
Reproductive efficiency in sows and boars affects the profitability of swine production systems. However, breeding stock selection is primarily based on progeny performance traits such as feed efficiency, growth rate, carcass characteristics, physical appearance, and structure, especially for terminal sire lines, with less emphasis on reproduction. While maternal sire lines are co-selected for reproductive traits including birth litter size, number weaned, weaning weight, and wean to estrus interval, currently, there is no single test predictive of fertility, and thus subfertile males and sub-fertile or even infertile females enter the swine breeding herds (Oh et al., 2006b; Safranski, 2008). Thus, to maximize economic returns and swine production efficiency there is a need for a biomarker to identify boars and gilts with the greatest reproductive potential before admittance into the breeding herd. The overall aim of the described studies was to determine if biomarkers of fertility of boars and gilts could be identified in biological samples taken prior to or just after animals entering the breeding herds using high throughput omic screening tools resulting from recent advancements in mass spectrometry. Current semen evaluation techniques only identify boars with fertility issues associated with sperm motility, morphology, and concentration. We know that seminal plasma proteins are essential for proper sperm function and play an important role in fertilization. Therefore, we hypothesized that fertility differences could be reflected in the seminal plasma proteome profiles. A fertility index was created from 110 boars with data on total born and farrowing rate following 50 single-sired matings. Thirty-two of the 110 boars were identified as having extreme phenotypes for total born and farrowing rate and were categorized into one of the following: high farrowing rate and high total born (HFHB; n=9), high farrowing rate with low total born (HFLB; n=10), low farrowing rate and low total born (LFLB; n=9), and low farrowing rate with high total born (LFHB; n=4). The seminal plasma proteins were isolated and measured using label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS). There were 436 proteins measured in at least one sample across all animals, with 245 proteins considered for analysis (detected in samples of at least n=3 animals/phenotype). Of the 245 proteins, 56 were differentially abundant (P< 0.05) between the high fertility phenotype (HFHB) and at least one of the three subfertile groups. Proteins previously associated with fertility such as Porcine seminal protein I (PSP-I) and epididymis-specific alpha-mannosidase (MAN2B2) and free radical detoxification such as superoxide dismutase 1 (SOD1), peroxiredoxin 4 (PRDX4), and glutathione peroxidase 6 (GPX6) were more abundant in HFHB. Subfertile phenotypes had a greater abundance of blood microparticle proteins, biomarkers of inflammation, and lower inositol-1-monophosphatase (IMPA1), which regulates inositol production. Findings supported that seminal plasma protein profiles were distinct between boars with different fertility phenotypes and have the potential to predict boar reproductive performance. The selection of replacement females for the sow herd is one of the most important facets in sow system management. However, selection of gilts for sow herd replacements is primarily based on how the animal appears such as feet and leg confirmation, the gilt’s underline, and parent past performance.
Degree
Ph.D.
Advisors
Casey, Purdue University.
Subject Area
Nutrition|Animal sciences|Public health
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