Deguchi E, Akuzawa M
Department of Veterinary Internal Medicine, Faculty of Agriculture, Kagoshima University, Japan.
J Vet Med Sci. 1998 Feb;60(2):149-53. doi: 10.1292/jvms.60.149.
One litter (Group A) of three unacquainted groups of littermates (4 piglets/litter), 64.0 +/- 0.8 days old, was moved to the pen of another litter (Group B) and they were housed together for 19 days after grouping (phase 1). The pigs in Group B violently attacked all the pigs in Group A for 9 hr after grouping. The remaining group was not grouped and used as controls. The plasma cortisol concentrations 1 hr after grouping were significantly higher than those 1 hr before and 24 hr after grouping, and the suppression of lymphocyte blastogenesis of peripheral blood mononuclear cells (PBMC) induced by mitogens was observed on 3, 8 and 19 days after grouping. After phase 1 ended, the pigs in Group A were returned to their own pen for 7 days, and then they were regrouped with the pigs in Group B and reared together for a further 14 days. Neither agonistic behavior nor change of plasma cortisol after regrouping was seen. Though the lymphocyte blastogenesis of PBMC induced by the mitogens on day 0 after regrouping was significantly lower in the pigs of Groups A and B compared to those in control pigs, a significant difference in lymphocyte blastogenesis among three groups was not seen on 7 and 14 days after regrouping. These findings indicate that fighting after grouping unacquainted litters increases plasma cortisol, and suppresses lymphocyte blastogenesis for 26 days after grouping.
一窝（A组）由三组互不相识的同窝仔猪（每组4头仔猪）组成，年龄为64.0±0.8天，将其转移到另一窝（B组）的围栏中，分组后（第1阶段）将它们饲养在一起19天。分组后，B组的猪对A组的所有猪进行了9小时的猛烈攻击。其余组不进行分组，用作对照。分组后1小时的血浆皮质醇浓度显著高于分组前1小时和分组后24小时，并且在分组后第3、8和19天观察到有丝分裂原诱导的外周血单个核细胞（PBMC）淋巴细胞增殖的抑制。第1阶段结束后，将A组的猪放回它们自己的围栏中7天，然后将它们与B组的猪重新分组并再一起饲养14天。重新分组后既未观察到攻击行为，也未观察到血浆皮质醇的变化。尽管重新分组后第0天有丝分裂原诱导的A组和B组猪的PBMC淋巴细胞增殖明显低于对照猪，但重新分组后第7天和第14天三组之间淋巴细胞增殖没有显著差异。这些发现表明，分组不相识的同窝仔猪后发生打斗会增加血浆皮质醇，并在分组后26天抑制淋巴细胞增殖。
