蛋鸡龙骨骨折在各饲养系统中发生率普遍较高,影响蛋鸡行为反应和福利水平.为研究产蛋后期龙骨骨折蛋鸡与未骨折蛋鸡竞争行为中是否处于劣势,采用触诊和X光仪判定体重相近的单只饲养于传统笼65周龄林甸鸡的龙骨状况,将蛋鸡分为龙骨正常组(NK)和龙骨骨折组(FK),开展配对争斗试验.而后在每个富集试验笼中将三只骨折蛋鸡和三只正常蛋鸡重新组群,研究骨折蛋鸡和正常蛋鸡社会竞争等级指数(CBI),再经食物竞争试验后剖杀部分骨折和正常蛋鸡,检测血液和龙骨组织炎症细胞因子表达.配对争斗试验结果表明,骨折蛋鸡得分显著低于正常蛋鸡(P＜0.05).重组群蛋鸡社会竞争试验结果表明,骨折林甸鸡CBI显著低于正常蛋鸡(P＜0.05).但采食竞争试验中骨折与正常林甸鸡采食时间差异不显著(P＞0.05).骨折蛋鸡龙骨组织炎症细胞因子mRNA相对表达水平和血清炎症因子浓度均高于正常蛋鸡(P＜0.05).试验表明龙骨骨折降低蛋鸡争斗能力,使其在社会竞争中处于不利地位,龙骨骨折引发的慢性炎症状态可能是骨折蛋鸡社会竞争行为表达下降的原因.

Footpad dermatitis (FPD) has a negative impact on the welfare and health production of poultry. The present study aimed to determine the effect of FPD on the expression of host defense peptides (HPDs). A total of fifty-four 55-week-old Hy-line brown hens housed individually in furnished cages were selected for investigating the mRNA expression of HPDs in foot, spleen, liver, and small intestine tissues. FPD score 0 group with normal foot, FPD score 1 with a small lesion of the foot pad epithelium and FPD score 2 with a larger lesion were divided by visual examination. The results showed that compared with group 0, hens from FPD group 1 and 2 had increased mRNA expression of HPDs of AvBD1, AvBD3, AvBD4, AvBD5, AvBD6, AvBD7, AvBD8, AvBD9, AvBD10, AvBD11, AvBD12, AvBD13, AvBD14 and LEAP2in foot and spleen tissues (P < 0.05). The relative expression of HPDs genes AvBD2, AvBD3, AvBD4, AvBD5, AvBD7, AvBD8, AvBD11, AvBD12, AvBD13, AvBD14, and LEAP2 in liver tissue increased, while the relative mRNA expression of AvBD6, AvBD9, and AvBD10 decreased (P < 0.05), and the expression levels of AvBD1, AvBD3, AvBD5, AvBD6, AvBD7, AvBD9, AvBD10, AvBD12, and LEAP2 in small intestinal tissue increased (P < 0.05), while the expression of AvBD2, AvBD8, and AvBD14 decreased (P < 0.05). Therefore, FPD can affect the expression of AVBDs in laying hens that the foot and spleen tissue had stronger responsiveness to the FPD. It is speculated that the increase in the expression of AVBDs on account of the possible infection with pathogenic bacteria. Then the increased HPDs participated in the host's defense responses and strengthened the immune regulation after FPD occurred.

钙(Ca)是家禽产蛋和维持骨骼健康最重要营养元素之一.为更好了解钙对蛋鸡龙骨微结构参数和骨骼元素浓度的影响,将180只罗曼白蛋鸡随机分成对照组和低钙饮食组,饲粮钙浓度分别为3.37％和1.5％.蛋鸡饲养于富集笼,每组6个重复,每个富集笼为1个重复,每个重复15只蛋鸡,试验周期20～37周.分别在第25、29、33和37周收集龙骨样品测量骨矿物质密度、骨微结构参数和骨元素浓度.结果表明,随蛋鸡年龄增加,低钙组蛋鸡正常龙骨比例减少,龙骨损伤率高于对照组,37周龙骨偏离率为31.25％,骨折率为56.25％.低钙组龙骨微结构参数与对照组相比,TV、Conn.D.、Tb.Sp、BS、BS/BV、BMD降低(P<0.05),BV、BV/TV、Tb.Th、DA增加(P<0.05).低钙组蛋鸡钾、铁、铜、锶、钼、锰、锌、钒、硒、铊、铅含量增加(P<0.05),钙、镍、锂、汞含量下降(P<0.05).产蛋期饲喂低钙水平日粮影响蛋鸡龙骨生长和代谢,改变龙骨骨密度、微观结构和元素稳态,损害龙骨质量和蛋鸡健康.

Keel bone damage negatively affects the welfare, production performance, egg quality, and mobility of laying hens. This study aimed to investigate whether abnormal bone metabolism causes keel bone damage in laying hens. Eighty Hy-line Brown laying hens were housed in eight furnished cages with 10 birds per cage and studied from 18 to 29 weeks of age (WOA). Accordingly, keel bone status was assessed at 18, 22, 25, and 29 WOA using the X-ray method, and the serum samples of laying hens with normal keel (NK), deviated keel (DK), and fractured keel (FK) that occurred at 29 WOA were collected across all the time-points. Subsequently, the serum samples were used to measure markers related to the metabolism of Ca and P and activities of osteoblast and osteoclast. The results showed that FK laying hens had lighter bodyweight than NK and DK birds throughout the trial (p < 0.05), while the keel bone length and weight were not different in NK, DK, and FK hens at 29 WOA (p > 0.05). Moreover, bone hematoxylin and eosin (H&E) staining and tartrate-resistant acid phosphatase (TRAP) staining indicated that damaged keel bone had evident pathological changes. In the FK hens, serum P level was reduced but serum 1,25-dihydroxy-vitamin D3 (1,25-(OH)2D3) and 25-hydroxyvitamin D3 (25-OHD3) levels were elevated compared to NK hens (p < 0.05). Additionally, DK hens had higher levels of serum 1,25-(OH)2D3, parathyroid hormone (PTH) and calcitonin (CT), and lower level of serum 25-OHD3 than the NK birds (p < 0.05). Furthermore, serum alkaline phosphatase (ALP), osteocalcin (OC), osteoprotegerin (OPG), TRAP, and corticosterone (CORT) levels were elevated in DK and FK hens compared to NK hens (p < 0.05). The levels of serum Ca, P, PTH, ALP, TRAP, OPG, OC, and CORT in laying hens fluctuated with the age of the birds. Generally, the results of this study indicate that keel bone damage, especially fractures, could be associated with abnormal bone metabolism in laying hens.