Federal Rural University of the Amazon (UFRA), Postgraduate Program in Animal Health and Production in Amazonia (PPGSPAA), Belém, Brazil.
Mamirauá Sustainable Development Institute (IDSM), Tefé, Brazil.
J Anat. 2022 Sep;241(3):741-755. doi: 10.1111/joa.13724. Epub 2022 Jul 7.
The study of fetal development allows for evaluating the different strategies adopted by mammal species to maximize neonatal survival. Autonomous locomotion is fundamental for newborns to perform foraging activities and increases newborn survival from predation. In this study, we assess the gestational bone development of 53 collared (CP, Pecari tajacu) and 61 white-lipped (WLP, Tayassu pecari) peccaries, collected through the collaboration of subsistence hunters in the Amazon. The bone mineralization and biometry of the axial and appendicular skeleton were assessed by ultrasound examinations, and the timing of the main bone developmental events was calculated in relation to the total dorsal length (TDL) and the percentage of the total gestational period (GP). The first US signs of mineralization of the axial skeleton in CP and WLP were observed in fetuses with 3.4 cm (42 gestation days, 30% GP ) and 5.1 cm (51 gestation days, 32% GP ). The early development of the appendicular skeleton was observed by the synchronic appearance of the mineralized scapula, humerus, radius, ulna, ilium, ischium, femur, tibia, and fibula at 36% GP (50 gestation days), and 35% GP (56 gestation days) The pubis was mineralized in fetuses at 55% GP (75 gestation days) and 59% GP (94 gestation days). The mineralization was observed in all autopod bones at 79% GP (109 gestation days) and 67% GP (106 gestation days). All primary ossification centers in long bones of thoracic and pelvic limbs were mineralized in advanced fetuses (GP GP ≥75%). The mineralized patella was not observed in advanced fetuses in either species. Secondary ossification centers first appeared at the distal epiphysis of the femur in the CP (99 gestation days, 72% GP ) and the distal epiphysis of the radius, femur, and tibia in the WLP (106 gestation days, 67% GP ). Advanced fetuses of CP and WLP presented 60% (15/25) and 68% (17/25) of the total secondary ossification centers observed present in the adult domestic pig, while newborns from the domestic pig presented 52% (13/25). The early intrauterine development of the skeletal system in both peccary species suggests a precocial development strategy, which likely correlates with neonatal ability to escape predators and reduces the dependence on parental care.
胎儿发育研究可以评估哺乳动物物种为最大限度提高新生儿存活率而采用的不同策略。自主运动对于新生儿进行觅食活动至关重要，并且可以提高新生儿免受捕食的存活率。在这项研究中，我们评估了通过亚马逊地区的生存猎人合作收集的 53 只（CP，Pecari tajacu）和 61 只（WLP，Tayassu pecari）白唇野猪的胎骨发育情况。通过超声检查评估了轴向和附肢骨骼的骨矿化和生物测量，并且根据总背长（TDL）和总妊娠期（GP）的百分比计算了主要骨骼发育事件的时间。CP 和 WLP 胎儿的轴向骨骼矿化的第一个 US 迹象出现在具有 3.4 厘米（42 个妊娠天，30% GP）和 5.1 厘米（51 个妊娠天，32% GP）的胎儿中。通过肩胛骨、肱骨、桡骨、尺骨、髂骨、坐骨、股骨、胫骨和腓骨的矿化同步出现，观察到附肢骨骼的早期发育，在 36% GP（50 个妊娠天）和 35% GP（56 个妊娠天）处出现。耻骨在 55% GP（75 个妊娠天）和 59% GP（94 个妊娠天）的胎儿中矿化。所有自动附肢骨骼在 79% GP（109 个妊娠天）和 67% GP（106 个妊娠天）处均观察到矿化。胸肢和骨盆肢的长骨中的所有初级骨化中心在晚期胎儿中均矿化（GP≥75%）。在这两个物种的晚期胎儿中均未观察到矿化的髌骨。次级骨化中心首先出现在 CP 的股骨远端骺（99 个妊娠天，72% GP）和 WLP 的桡骨、股骨和胫骨的远端骺（106 个妊娠天，67% GP）。CP 和 WLP 的晚期胎儿分别有 60%（25 个中的 15 个）和 68%（25 个中的 17 个）观察到的成年家猪的总次级骨化中心存在，而新生的家猪有 52%（25 个中的 13 个）。这两个野猪物种的早期宫内骨骼系统发育表明存在早产发育策略，这可能与新生儿逃避捕食者的能力相关，并降低对父母照顾的依赖。
