Use of the spectrophotometric color method for the determination of the age of skin lesions on the pig carcass and its relationship with gene expression and histological and histochemical parameters.

The presence of lesions on the pig carcass is an indicator of poor animal welfare and has economic impact as it downgrades the carcass value. The assessment of the age of lesions on the carcass may help identify risk factors and ultimately prevent their occurrence. The aim of this study was to assess the age of lesions on pig carcasses through spectrophotometric color evaluation and to relate the results with gene expression and histological and histochemical parameters. A total of 96 barrows were mixed 4 times over 3 d before slaughter and 80 lesions were selected after skin lesion observations to define 4 age categories: < 7 h (T1), 7-25 h (T2), 25-30 h (T3), and 49-54 h (T4). A nonlesioned skin area was used as a control. At slaughter, 3 biopsies per lesion and control skin were taken immediately after bleeding for analyses of gene expression (, , , , , , , , , ), skin histological characteristics (inflammation, erosion or ulceration, and necrosis), and enzyme activity (alkaline phosphatase and adenosine triphosphatase). The number of lesions was counted on each carcass, and the color was assessed visually by a pictorial chart and instrumentally through a spectrophotometer. Delta values (Δ) were calculated as the difference between the value of the lesion and the value of the control for all measures, except for the histological analysis. Results indicated that visual color observation was not sufficiently accurate to discriminate lesions by time of infliction ( > 0.10), while the spectrophotometer ΔL* and Δa* values variation allowed the identification of < 7 h or > 25 h old lesions ( < 0.05). Similarly, the expression of , , , , and genes was higher ( < 0.05) in < 7 h old lesions, while gene expression was higher ( < 0.05) in < 25 h old lesions. As for the histological analysis, the severity of inflammation was correlated with the age of the lesion (lower score in < 7 h old lesions and higher score in > 25 h old lesions; < 0.05). To conclude, the spectrophotometric color assessment of the carcass lesions at slaughter appears to be a reliable method to discriminate between fresh and older lesions on the carcass at the abattoir.

Effect of oestrous cycle and early pregnancy on uterine production and expression of immune regulatory factors in gilts.

This study was undertaken to characterize uterine immune factors involved in the establishment of pregnancy in gilts. Thirty crossbred Yorkshire-Landrace gilts of similar age and weight were observed twice a day for oestrous behaviour with intact boars. On the day of first standing oestrus (Day 0) and 12h later, 15 gilts were inseminated with pooled semen from Duroc boars of proven fertility. Pregnant gilts were slaughtered either on Days 10, 15 or 25 of gestation (n=5 per day). The other 15 gilts were not inseminated and were slaughtered on either Days 0, 10 or 15 of the oestrous cycle (n=5 per day). Immediately after slaughter, endometrial tissue samples from the mesometrial side were removed for gene expression using RNase protection assay and in situ hybridization methodologies. The other uterine horn was flushed with 20 ml of PBS to collect the uterine fluid. In pregnant gilts, endometrial interleukin (IL)-6 mRNA expression was higher on Day 15 than on Days 10 and 25 (P<0.01 and P<0.1, respectively). On Day 15, IL-6 expression was also significantly higher (P<0.01) in pregnant gilts than in cyclic gilts. In both pregnant and cyclic gilts, transforming growth factor (TGF)-beta2 in uterine fluid was significantly higher (P<0.0001) on Day 15 than on Day 10. At the gene expression level, TGF-beta2 also increased between Days 10 and 15 in both cyclic and pregnant gilts but differences were not significant. On Day 15, concentrations of interferon-gamma and prostaglandin E(2) (PGE(2)) in uterine fluid were markedly higher (P<0.001) in pregnant gilts than in cyclic gilts, whereas the total amount of TGF-beta2 in uterine fluid and its endometrial expression were approximately 70% higher although this increase was not significant. Finally, tumour-necrosis factor-alpha and granulocyte-macrophage/colony-stimulating factor mRNA expressions were undetectable in all endometrial samples. In conclusion, production and/or expression of uterine TGF-beta2, IL-6 and PGE(2) increased during the embryonic attachment period and are coincidental with embryonic interferon-gamma production.

Effect of folic acid and glycine supplementation on embryo development and folate metabolism during early pregnancy in pigs.

The present work aimed to determine if different levels of prolificacy either by parity or by genetic origin are linked to folate metabolism. Nulliparous Yorkshire-Landrace (YL) and multiparous YL, and multiparous Meishan-Landrace (ML) sows were randomly assigned to two treatments: 0 ppm or 15 ppm folic acid+0.6% glycine. Supplements were given from the estrus before mating until slaughter on d 25 of gestation. At slaughter, embryo and endometrial tissues were collected to determine concentrations of DNA, protein, and homocysteine. Allantoic fluid samples were also collected to determine concentrations of folates, vitamin B12 and amino acids. Blood samples were taken at first estrus, at mating, and on d 8, 16, and 25 of gestation to determine serum concentrations of folates, vitamin B12, and relative total folate binding capacity (TFBC). Over the entire experiment, multiparous YL sows had higher average serum concentrations of folates than nulliparous YL sows (P < 0.05) but had similar serum concentrations of relative TFBC. Concentrations of folates and relative TFBC averaged higher in ML measured over the entire experiment than in multiparous YL sows (P < 0.05). Concentrations of serum vitamin B12 were higher in multiparous YL than in ML sows or YL nulliparous sows (P < 0.05) over the entire experiment. In allantoic fluid, folates, vitamin B12, and essential amino acids contents were significantly lower in ML than in YL multiparous sows (P < 0.05). The folic acid+glycine supplement increased concentrations of serum folates, but the increase was more marked in nulliparous YL sows (nulliparous x folic acid+glycine, P < 0.05). The folic acid+glycine supplement had no effect on litter size and embryo survival, but it tended to increase embryo DNA in multiparous YL sows (P = 0.06) but not in ML and nulliparous YL sows. Homocysteine was decreased by folic acid+glycine supplement in embryos from all sows, but in endometrium, the folic acid+glycine effect was dependent on parity (nulliparous x folic acid+glycine, P < 0.05). The effects of folic acid+glycine on litter size and embryo development and survival and some aspects of folate metabolism suggest that the basal dietary content of folic acid+glycine was adequate for ML and nulliparous YL sows but not to optimize embryo development in YL multiparous sows.

Effects of breed, parity, and folic acid supplement on the expression of leptin and its receptors' genes in embryonic and endometrial tissues from pigs at day 25 of gestation.

Recent evidence has pointed toward a possible role of leptin (Lep) and its receptor (Lepr) in early gestation materno-fetal cross-talk. However, in gestating sows, exhaustive characterization of leptin mRNA expression in backfat and leptin-receptor mRNA expression in endometrial and embryonic tissues is still pending. The objectives of this study were to characterize the Lep, Lepr, and long Lepr-L isoform mRNA expression according to the breed and parity of gestating sows or to specific folic acid (B(9)) + glycine dietary treatments. To this end, nulliparous (GT) and multiparous occidental Yorkshire-Landrace (YL) sows as well as multiparous Chinese Meishan-Landrace (ML) sows were used. These sows were randomly assigned to two different dietary treatments: 0 or 15 ppm of B(9) + 0.6% glycine, given from the estrous preceding mating until slaughter on Day 25 of gestation. Jugular blood samples were collected at mating and on Day 25 of gestation and assayed for circulating leptin concentrations. Expression levels of Lep in backfat and of Lepr and Lepr-L in endometrial and embryonic tissues were performed using semiquantitative reverse transcription-polymerase chain reaction. Results demonstrated that on Day 25 of pregnancy, the ML sows showed higher concentrations of circulating leptin along with higher backfat thickness and higher expression of Lep in backfat tissue. Moreover, in embryonic tissues, the mRNA expression levels of Lepr and Lepr-L genes were higher in ML than in YL sows. Parity effects were observed for mRNA expression of Lepr in both endometrial and embryonic tissues, whereas mRNA levels were higher in YL than in GT sows. In addition, embryonic Lepr-L mRNA levels were higher in GT than in YL sows, and B(9) + glycine dietary supplement decreased the mRNA expression levels of Lep in backfat and of Lepr in embryonic tissues. These decreases were independent of breed or parity of the sows. The effect of B(9) + glycine on Lepr-L mRNA expression levels was only seen in YL sows, whereas the treatment lowered Lepr-L expression levels in both endometrial and embryonic tissues. These results indicate that leptin and its receptor may play a role during early stages of development of the pig embryo-fetus, and that these roles could be modulated according to the breed and parity of the sows. Moreover, the effects of B(9) + glycine on expression levels of embryonic and endometrial Lepr-L mRNA in YL sows may explain the previously reported effects of B(9) on embryo survival rate and litter size observed in occidental multiparous sows.