ICAR-Central Coastal Agricultural Research Institute, Goa, India.
ICAR-Central Coastal Agricultural Research Institute, Goa, India.
J Therm Biol. 2024 Oct;125:103985. doi: 10.1016/j.jtherbio.2024.103985. Epub 2024 Sep 30.
Assessing the adaptability of slow-growing rural chickens for improving thermotolerance to suit the global climate change is a major research need. This work was aimed to evaluate the adaptability of CARI-Debendra chickens and to identify the polymorphism as well as expression profiling of thermotolerant genes (HSP70 and GRP78) under prevailing temperature-humidity indices and thermal stress in a coastal environment. One hundred sixty straight run chicks were reared at THI≥75 (control) and THI>80 under coastal climate till 12 weeks. Polymorphism of HSP70 and GRP78 candidate genes were explored using restriction enzymes TaqI and HaeIII to identify possible thermotolerance markers. Expression profiling of both the genes in liver, intestine and pectoralis muscle was determined through quantitative real-time PCR. Rectal and body surface temperature recorded in the neck and back showed significant differences (P < 0.01) with higher temperature in THI>80 group. Comparatively lower live weights (P < 0.05) and poor FCR were recorded in THI>80 group. The villi height in all intestinal segments was significantly lower (P < 0.01), but deeper crypt depth was observed in THI>80 than control group. A lowest thymus weight (P < 0.05) was noted with no significant differences in immune response in treatment group. Serum levels of cholesterol, activities of lactate dehydrogenase, creatinine kinase and concentration of potassium, sodium and thyroxine hormone were not different between the 2 groups. The concentration of triiodothyronine and chloride ion was lower in THI>80 group indicating adaptive changes for thermoregulation. HSP70 gene expressions in the three tissues were differentially increased (P < 0.01) by temperature-humidity indices, but the expression of GRP78 was not different between the 2 groups. The results concluded that the environmental factors interact with genetics on adaptability towards thermotolerance in slow-growing chickens.
评估生长缓慢的农村鸡的适应性，以提高其对全球气候变化的耐热性，是一项重大的研究需求。本研究旨在评估 CARI-Debendra 鸡的适应性，并在沿海环境下，根据现有的温度-湿度指数和热应激条件，鉴定耐热基因（HSP70 和 GRP78）的多态性和表达谱。将 160 只直线育雏鸡在 THI≥75（对照）和 THI>80 条件下饲养至 12 周，直到 12 周。利用 TaqI 和 HaeIII 两种限制酶探索 HSP70 和 GRP78 候选基因的多态性，以确定可能的耐热性标记。通过定量实时 PCR 确定肝脏、肠道和胸肌中这两个基因的表达谱。颈部和背部的直肠和体表温度记录显示出显著差异（P<0.01），THI>80 组的温度较高。THI>80 组的活重（P<0.05）和较差的饲料转化率较低。所有肠段的绒毛高度均显著降低（P<0.01），但 THI>80 组的隐窝深度较对照组更深。胸腺重量最低（P<0.05），但治疗组的免疫反应无显著差异。两组间血清胆固醇、乳酸脱氢酶、肌酸激酶和钾、钠、甲状腺素激素浓度无差异。THI>80 组三碘甲状腺原氨酸和氯离子浓度较低，表明其对体温调节的适应性变化。HSP70 基因在三种组织中的表达均因温度-湿度指数而不同程度地增加（P<0.01），但 GRP78 在两组间的表达无差异。结果表明，环境因素与遗传因素相互作用，影响生长缓慢的鸡对耐热性的适应性。
