Effects of a chronic stress treatment on vaccinal response in lambs

Sexual performance and semen quality of pubertal lambs treated with different weaning methods

The objective of this study was to determine the effect of the weaning method on lamb stress, body weight, sexual behavior, and semen quality of Saint Croix male lambs. The present study was carried out during the late spring and summer of 2018 in the northeast of Mexico. Sixty male lambs born as twins or triplets (3.2 ± 0.6 kg birth weight) and weaned at 60 d of age (19.21 ± 1.8 kg weaning weight) were divided into two weaning methods: complete separation from the dams (CS; the lambs were moved to a pen that was at 500 m of distance from the dams) and separation with contact from the dams (SCD); the lambs were physically separated by a steel mesh that prevented the lambs from having the possibility of sucking milk from their mothers, but they maintained permanent visual and auditory contact. Cortisol levels were determined 3 d before and 7 d after weaning. Lambs were evaluated as 3-month-old lambs for sexual behavior and semen quality for 9 weeks. The effects of the weaning method (M), week (W), and the interaction M × W were significant on body weight and cortisol levels (P<0.001). The SCD lambs had higher cortisol levels at 3, 5, and 7 d after weaning than CS lambs (P<0.001). The CS lambs had higher body weight during the first 4 weeks after weaning than SCD lambs (P<0.001). The weaning method had no effect on scrotal circumference, sexual behavior, and semen quality traits, except for progressive sperm motility, being better for the lambs that were completely separated (P<0.05). The results from this study show that complete separation of lambs and ewes at weaning is an effective method to reduce lamb stress and improve lamb growth after weaning, but it did not have long-term effects on sexual behavior and semen quality of Saint Croix male lambs.

Identification of potential serum biomarkers in pigs at early stage after Lipopolysaccharide injection

The identification of useful biological indicators to monitor the body response before the presentation of clinical diseases has practical value in livestock production. To identify potential biomarkers in pigs at the early stage during inflammation, 12 pigs were intramuscularly injected with 2mL of Lipopolysaccharide (LPS, 15μg/kg BW) or saline. Serum protein expression profiles were detected with two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) techniques. Serum biochemical indicators and acute phase protein (APP) concentrations were analyzed with an automatic biochemical analyzer and ELISA, respectively. Of the serum biochemical indicators, creatinine concentration significantly increased 6h post infection, whereas albumin showed a decreased tendency. The 2-DE and MALDI-TOF mass spectrometry technique detected 17 protein spots representing 10 proteins: α-1-antichymotrypsin, albumin, bovine lactoferrin, serotransferrin, serpin A3-6, immunoglobulin light chain (κ chain, mu chain), complement C3 precursor, zinc-α-2-glycoprotein (ZAG), and ceruloplasmin. Two proteins were selected to confirm the mass spectrometry results, and resulting differences accorded with the proteomics results. Of the four typical acute phase protein (APPs) measured, the C-reactive protein (CRP) and haptoglobin (HP) concentrations increased significantly, while no differences were observed in the pig-major acute phase protein (Pig-MAP) and transthyretin (TTR) contents. The results showed that serum creatinine, CRP, HP, and ten other proteins content changed significantly after LPS injection. Of these proteins, ZAG was first reported in pigs during inflammation. These proteins show great promise as biomarkers to monitor the health status and welfare of pigs during the early stage of LPS-induced inflammation.