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.

Litters, the composition of sand and peat rich in microbiota, are essential to trigger the dustbathing behavior of chickens. To investigate the effects of a dustbathing environment (DE) on the intestinal health, gut microbiota, and immune responses of laying hens, a total of 72 healthy Hy-Line Brown laying hens at 69 wk of age (WOA) were housed individually in modified traditional cages and randomly divided into 2 groups: one group had free access to litters (CT), while the other one was restricted from litters (CC). The experiment lasted for 42 d. At the end of the experiment, the intestinal histomorphology and immune status of laying hens were determined, and the 16S rRNA sequencing method was used to assess the composition of the intestinal microbial community of birds. Intestinal histomorphology changed, including villus height and villus-to-crypt ratio significantly increased in the CT group (P < 0.01). DE reshaped the microbial community and increased the microbial richness with the higher indicators of Chao1 and observed species and the comparatively abundant beta diversity (P < 0.05). Ten genera, including Faecalibacterium and Coprococcus, declined in laying hens from the CT group (P < 0.05), while Alistipes increased in CT hens (P < 0.05) compared to those hens from the CC group. The expression levels of intestinal barrier-related genes of claudin-1, claudin-4, occludin, ZO-1, and ZO-2 and immune-related genes of IL-4, IL-6, IL-8, IFN-γ, IgA, TLR-2, and TLR-4 were significantly upregulated in the intestine of laying hens in CT group (P < 0.05). DE also increased the serum levels of IL-4, IL-6, IL-8, IFN-γ, and IgA (P < 0.01). The alteration of the gut microbiota by DE is closely related to host immune responses, including Lactobacillus positively correlated with IL-4 and IgA. Thus, a dustbathing environment can improve the welfare of laying hens by changing the intestinal histomorphology, immune response, and the gut microbial community.

沙浴行为是鸡的一种自然行为,具有重要的生理功能.随着蛋鸡和肉鸡养殖模式的福利化改革,目前在多种饲养模式下都可以观察到鸡的沙浴行为.然而,沙浴行为发生的原因、沙浴行为表达的影响因素及沙浴行为对动物福利产生影响等问题尚未完全明晰.本文主要综述了沙浴行为和假沙浴行为的动机假说、沙浴的行为学功能、沙浴行为的主要影响因素及其与动物福利的关系,为生产实践通过行为管理提高动物福利水平提供理论依据.

Keel bone fracture (KBF) of laying hens has become one of the important welfare problems for health and production performance. The present study aimed to assess the fear responses in native breed of Lindian chickens and commercial Hyline Brown laying hens with and without KBF at the late laying period. At their 56-week-age, a total of 76 Hyline Brown hens and 80 Lindian hens selected from furnished cages were housed individually in battery cages. The laying hens were divided into normal group and keel fracture group. The fear tests, including tonic immobility tests (TI), open field tests (OFT), and startle reflex tests (SRT) were measured sequentially. The fractured laying hens from two breed had significant elevated duration time in the TI test than that of normal laying hens (P < 0.05). In OFT test, the number of grids, steps, and time spent in the outer ring of fractured Lindian hens were significantly less than those of normal hens (P < 0.05), and the time spent in the inner ring was significantly greater (P < 0.05). The movement latency and the time spent in the inner circle of fractured Hyline Brown hens were significantly greater than those of normal hens (P < 0.05), but the number of grids and steps passed and the time spent in the outer ring were significantly less than those of normal hens (P < 0.05). There was no significant difference in call latency and total call between fractured and normal hens of Lindian and Hyline Brown strain (P > 0.05). The total score of startle reflex of Lindian hens with keel fracture was significantly less than that of normal laying hens (P < 0.05). Therefore, keel fracture reduced the welfare of laying hens in the later stage of laying by affecting their behavioral fear responses.

To investigate the effects of stocking density on the welfare and immune responses of laying hens housed in furnished cages, 192 Hy-Line Brown hens were housed in small furnished cages and randomly divided into three groups on their 18 weeks old for low-density group (833 cm2 per hen, LD), medium-density group (625 cm2 per hen, MD), and high-density group (500 cm2 per hen, HD). There are eight cages in each stocking density. The welfare of laying hens was assessed at 22, 42 and 72 weeks of age (WOA) for feather quality, foot cleanness, footpad dermatitis, hyperkeratosis and keel bone damage. After the last welfare assessment, venous blood from the wing of the hen was extracted for testing immune indicators of Immunoglobulin Y (Ig Y), Interferon gamma (IFN-γ), Transforming growth factor beta (TGF-β), Interleukin-2 (IL-2), Interleukin-4 (IL-4), Interleukin-6 (IL-6), Interleukin-12 (IL-12) by enzyme-linked immunosorbent assay (ELISA). Results showed that feather quality of laying hens from HD group was worse than hens from LD and MD groups at 42 and 62 WOA (P < 0.05). The foot cleanness score of hens from HD group was worse than other two group hens at 62 WOA (P < 0.05), respectively. There was no significant difference between three groups on other welfare indicators (P > 0.05), but the welfare quality of laying hens got worse with the aging of laying hens. Laying hens from LD group had greater concentrations of serum IFN-γ, IL-2, IL-6 compared with hens from MD and HD groups (P < 0.05). There was no significant difference for other immune responses (P > 0.05). These findings suggest that keeping a high stocking density of laying hens could cause feather damage, impact the welfare quality and reduce the immune responses of laying hens housed in small furnished cages.

Keel bone damage (KBD) is more prevalent in alternative laying hen housing systems than in conventional cages, and its incidence differs from strain to strain. However, the information of KBD in Lindian chickens, a native Chinese strain, is limited. To investigate the effect of KBD on fearfulness and physiological indicators of stress in Lindian chickens and commercial laying hens, a total of two hundred 25-week-old chickens (100 Hy-line Brown and 100 Lindian chickens) were studied for 7 weeks. The birds were housed in furnished cages with 10 birds per cage for each strain. At 32-week of age, the birds in each strain were divided into normal (NK), deviated (DK) and fractured (FK) hens according to the keel bone status. Ten birds in each keel bone status per strain were subsequently selected to collect blood for the determination of stress and fear-related indicators, including corticosterone, serotonin, interleukin-1β and interleukin-6, and measure fear responses, including novel object test (NOT), human approach test (HAT), and tonic immobility (TI) test. The results showed that egg production was lower and the incidence of keel bone fractures was higher in Lindian chickens than in Hy-line Brown hens (P < 0.05). Lindian chickens showed a significantly increased whole blood serotonin content, NOT-latency, HAT-score, and TI induction times (P < 0.05) and decreased serum interleukin-6 content and TI-duration (P < 0.05) compared to Hy-line Brown hens. Additionally, FK hens had significantly elevated whole blood corticosterone, serum interleukin-1β and interleukin-6 levels, TI-duration and NOT-latency (P < 0.05), and a reduced whole blood serotonin content (P < 0.05) compared to NK and DK hens. Our results indicated that KBD affected stress and fear responses, and this impact was mainly reflected by FK hens compared to NK and DK hens. We suggest that keel bone fractures are the main factor impairing hen welfare. Besides, the incidence of keel bone fractures and stress and fear responses of Lindian chickens are more severe than Hy-line Brown laying hens, indicating that the strain type can affect the health and welfare of laying hens.

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.

Noise is a potential but not negligible environmental factor in animal husbandry. To investigate the effects of farm noise on intestinal barrier function of pullets, 336 Hailanhe pullets aged 1 day were randomly divided into 3 groups: control group (CON), low noise group (LN), high noise group (HN). LN group and HN group were exposed to noise respectively at 65–75 dB and 85–95 dB, the average and the range of the highest loudness of noise in laying hens’ farms for 6h every day (7:00-19:00, hourly intervals for one hour) and lasted 4 weeks. Non additional noise addition in CON group, noise loudness of which was less than 40dB. 6 birds were randomly chosen form each group after every week of noise stimulation for ileum tissue samples. Hematoxylin-eosin stain (HE stain), immunofluorescence, and real-time quantitative PCR (qRT-PCR) were used to determine changes in ileum structure, expression of intestinal barrier related proteins and mRNAs and HSPs. Results shown that 1 week and 2 weeks after noise exposed inflammatory cell infiltration reduced, the expression of intestinal barrier related proteins (Occludin, Mucin2 and ZO-1) and mRNAs (Claudin-1, Claudin-4, E-cadherin, Occludin, Mucin2, ZO-1 and ZO-2) were significantly increased (P < 0.05), the mRNA expression of HSPs decreased (P < 0.05) or have no significate changes (P > 0.05). After 4 weeks of noise treatment, the expression of mRNAs of intestinal tight junction protein and mucin, HSPs were significantly decreased (P < 0.05). There was no difference between the LN and HN groups on those indicators (P > 0.05). The study indicates that noise at 65-75dB and 85-95dB does not cause stress to ileum of pullets while promote the development of intestinal barrier of chicks within 2 weeks maybe by mild stimulation and birds restored to balance due to habitualization after 4 weeks of noise treatment.