镉(Cd)已被公认为毒性最强的重金属之一,通过人为(工业活动,化肥生产,和废物处理)和人为来源的自然来源的贡献大于自然来源。因此,饲料中的Cd浓度有时会增加,饲料,水体,以及工业区附近的牲畜组织,包括家禽,导致新陈代谢,结构,以及所有动物不同器官的功能变化。在家禽中,Cd的生物积累主要发生在肝脏的几个器官中,肾,肺,和生殖器官由于其持续暴露。Cd的摄入降低了家禽的生长和产蛋性能以及饲料转化效率。低剂量镉的慢性暴露也可以改变组织的微观结构,特别是在肝脏中,肾,大脑,胰腺,肠,和生殖器官由于这些组织中Cd含量的增加。由于活性氧的过度产生,持续的Cd暴露会导致细胞水平的氧化应激增加,疲惫的抗氧化剂防御机制。这导致生物相关分子的破坏,特别是核酸,蛋白质和脂质,随后细胞凋亡,细胞损伤,和坏死细胞死亡。肝脏的组织病理学改变,肾脏,和其他器官在血象和血清生化和酶活性上有不利反映。本综述讨论了Cd在不同组织中的生物积累和组织病理学改变,Cd毒性的发病机理,血液生化变化,及其在家禽中的不同改善措施。
Cadmium (Cd) has been recognized as one of the most toxic heavy metals, which is continuously discharged into environments through anthropogenic (industrial activities, fertilizer production, and waste disposal) and natural sources with anthropogenic sources contributing greater than the natural sources. Therefore, Cd concentration sometimes increases in feeds, fodders, water bodies, and tissues of livestock including poultry in the vicinity of the industrial areas, which causes metabolic, structural, and functional changes of different organs of all animals. In poultry, bioaccumulation of Cd occurs in several organs mainly in the liver, kidney, lung, and reproductive organs due to its continuous exposure. Intake of Cd reduces growth and egg laying performance and feed conversion efficiency in poultry. Chronic exposure of Cd at low doses can also alter the microscopic structures of tissues, particularly in the liver, kidney, brain, pancreas, intestine, and reproductive organs due to increased content of Cd in these tissues. Continuous Cd exposure causes increased oxidative stress at cellular levels due to over-production of reactive oxygen species, exhausting antioxidant defense mechanisms. This leads to disruption of biologically relevant molecules, particularly nucleic acid, protein and lipid, and subsequently apoptosis, cell damage, and necrotic cell death. The histopatholocal changes in the liver, kidneys, and other organs are adversely reflected in hemogram and serum biochemical and enzyme activities. The present
review discusses about Cd bioaccumulation and histopathological alterations in different tissues, pathogenesis of Cd toxicity, blood-biochemical changes, and its different ameliorative measures in poultry.