实验性热应激对肉仔鸡免疫器官的影响

对实验性热应激肉仔鸡的免疫器官的组织学变化、超微组织学变化进行了动态观察，对热应激造成的免疫器官的细胞凋亡及免疫反应能力进行了检测。结果表明，热应激可引起免疫器官胸腺、脾脏、法氏囊的发育分化不良，使法氏囊指数、脾脏指数明显下降，胸腺指数虽有下降，但幅度较小；热应激对免疫器官的组织结构有显著影响，尤其对法氏囊和脾脏的影响更明显，主要表现为实质细胞的萎缩、消失性病变，但无明显的实质细胞崩解坏死、炎性细胞浸润、炎性充血等病理变化，并随热应激时间的延长而逐渐加重，最后以实质细胞几乎完全消失、间质结缔组织增生而纤维化告终。热应激可显著影响试验鸡血清新城疫病毒抗体滴度，与对照相比，其抗体滴度的峰值低，维持时间短，下降速度快；通过电镜观察和细胞凋亡的原位检测，证实热应激时免疫器官的淋巴细胞和巨噬细胞有凋亡现象，这种凋亡现象在早期尤其显著。     

实验性热应激对肉仔鸡免疫器官的影响

对实验性热应激肉仔鸡的免疫器官的组织学变化、超微组织学变化进行了动态观察,对热应激造成的免疫器官的细胞凋亡及免疫反应能力进行了检测.结果表明,热应激可引起免疫器官胸腺、脾脏、法氏囊的发育分化不良,使法氏囊指数、脾脏指数明显下降,胸腺指数虽有下降,但幅度较小;热应激对免疫器官的组织结构有显著影响,尤其对法氏囊和脾脏的影响更明显,主要表现为实质细胞的萎缩、消失性病变,但无明显的实质细胞崩解坏死、炎性细胞浸润、炎性充血等病理变化,并随热应激时间的延长而逐渐加重,最后以实质细胞几乎完全消失、间质结缔组织增生而纤维化告终.热应激可显著影响试验鸡血清新城疫病毒抗体滴度,与对照相比,其抗体滴度的峰值低,维持时间短,下降速度快;通过电镜观察和细胞凋亡的原位检测,证实热应激时免疫器官的淋巴细胞和巨噬细胞有凋亡现象,这种凋亡现象在早期尤其显著.     

氯化钾对热应激肉仔鸡生产性能的影响

本试验测定了氯化钾对热应激肉仔鸡生产性能的影响。试验应用２ｌ０只星布罗肉仔鸡，随机分成７组，每组３０只。氯化钾按０％、　０．０６％、０．１２％、０．１８％、０．２４％、０．３０％和０．３６％添加到饮水中，试验温度为３２±１℃，试验期为３５天。结果表明饮水中添加０．２４％、一０．３０％氯化钾能显著提高热应激条件下肉仔鸡的生产性能。     

抗应激药物对热应激肉鸡免疫器官的组织学影响

２００只１４日龄健康艾维茵肉仔鸡随机等分为四组,Ａ、Ｂ两组分别在饲料中添加０．２２５％的抗应激Ⅰ号和抗应激Ⅱ号,Ｃ组为热应激对照组,Ｄ组为常温对照组。Ａ、Ｂ、Ｃ三组鸡舍温度为２８,３２～３６℃,４９日龄时称重、杀死、取材作石蜡切片,观察免疫器官的组织学结构。结果表明,Ｃ组体重明显低于Ａ、Ｂ、Ｄ组,Ａ、Ｂ组鸡体重与Ｄ组间差异不显著。热应激对各免疫器官有明显的损伤性和免疫抑制样变化,而抗应激药物对免疫器官有明显的保护作用,从组织学角度看,抗应激药物可明显地对抗热应激所造成的免疫抑制,使免疫器官组织学结构接近正常水平。     

热应激对肉仔鸡生产性能及肉品质的影响

试验选270只28日龄AA肉用公鸡,随机分为3组,每组6个重复,每重复15只鸡.采用配对试验设计,高温组为28～34～28℃日变高温,适温自由采食组和适温配对组都为22℃,适温配对组鸡喂给高温组前1d的饲料采食量.于试验第21天检测各组鸡胸肌和腿肌肉品质.,试验结果表明:1)热应激显著降低肉鸡的采食量和生长速度,降低饲料转化率.2)高温环境显著影响鸡肌肉一些感观指标,使肉品质下降.     

中药添加剂对热应激肉用仔鸡生产性能的影响

以60只20日龄肉仔鸡进行试验,在热应的条件下于日粮中加中药添加剂,探讨肉仔鸡的日增重、料重比、屠宰性能及经济效益情况。结果表明,高温下,肉仔鸡日粮中加中药添加剂,抗热应激效果好,经济效益佳。     

日粮核黄素水平对热应激条件下肉仔鸡生产性能的影响

本试验采用360只21日龄ArborAcres商品代肉仔鸡 ,随机分成6组 ,每组3个重复 ,每个重复20只鸡 ,公母各半。试验期为5周。研究日粮核黄素水平对热应激条件下肉仔鸡生产性能的影响。日粮中添加的核黄素水平分别为0、1.6、5.2、12.4、23、48mg/kg。试验结果表明 ,高温条件下核黄素添加水平对21～42日龄肉仔鸡平均日增重、料重比无显著影响 (P>0.05)。添加12.4及23mg/kg 核黄素组与对照组相比显著增加了43～56日龄肉仔鸡的平均日增重 ,分别增高30.66 %和35.70 % (P<0.05) ,但对料重比无显著影响(P>0.05)。添加不同水平的核黄素可以显著降低肉鸡的死亡率 (P<0.05) ,显著降低热应激条件下生长中期肉鸡的血清肌酸激酶水平 (P<0.05)。随着日龄的增加 ,在试验中期 (4～6周 ) ,添加不同水平的核黄素日粮可以降低肉鸡14:00的呼吸率 ;在试验后期 (6～8周 ) ,添加12.4mg/kg 水平的核黄素日粮可以降低肉鸡9:00的呼吸率。随着环境温度的升高 ,将日粮核黄素水平提高到48mg/kg有降低肉鸡生长后期肛温的作用(P<0.05)。     

早期饲喂对肉仔鸡生产性能和免疫器官发育的影响

选择刚出壳的AA肉仔鸡200只,随机分成2组,每组设4个重复,每个重复25只鸡,进行饲养试验.早期饲喂组在出壳3 h饲喂超前期日粮,早期禁食组在出壳48 h后饲喂常规肉雏鸡日粮.早期饲喂组于6日龄全部换为常规日粮.在试验的第21、42、49日龄称重、翅静脉采血,研究早期饲喂对生产性能、血清尿素氮和新城疫(NDV)抗体水平的影响.在21、42日龄采用收粪法分别进行2次代谢试验,测定氮沉积率.在试验结束时,进行屠宰试验,研究早期饲喂对胸肌率和免疫器官指数的影响.结果表明:(1)早期饲喂能显著的提高肉仔鸡各阶段的平均体质量(P＜0.05),0～21日龄鸡的氮沉积率显著高于早期禁食组(P＜0.05),血清尿素氮显著低于早期禁食组(P＜0.05),死亡率降低6%.(2)早期饲喂组鸡的免疫器官指数显著的大于早期禁食组(P＜0.05),并显著的提高了NDV抗体水平.(3)早期饲喂对胸肌率和腿肌率有显著的影响,与早期禁食组相比,胸肌率提高了2.14%而腿肌率下降了0.93%.     

日粮锌铜水平对肉仔鸡生产性能和免疫器官发育的影响

试验选用378只1日龄爱拔益加(AA)公雏,采用3×2因子设计,通过饲养试验和屠宰试验研究了日粮添加不同水平的Zn(25mg/kg、85mg/kg、165mg/kg)和Cu(10mg/kg、25mg/kg)对肉仔鸡生产性能和免疫器官发育的影响。饲养试验结果表明:①除在1～3周龄,处理Ⅱ(Zn85mg/kg和Cu10mg/kg)和处理V(Zn85mg/kg和Cu25mg/kg)与处理Ⅲ(Zn165mg/kg和Cu10mg/kg)的日增重差异显著(P<0.05)外,其它各阶段,各处理的生产性能均差异不显著(P>0.05);②Zn水平除对1～3周龄的日增重有显著影响外(P<0.05),对其它各阶段的生产性能无显著影响(P>0.05);③Cu水平及Zn、Cu互作对各阶段的生产性能亦无显著影响(P>0.05)。屠宰试验结果表明:Zn、Cu水平及Zn、Cu互作对肉仔鸡的免疫器官重量及其指数均无显著影响(P>0.05)。结果表明,肉仔鸡日粮中适宜的Zn添加量为85mg/kg,Cu添加量10mg/kg和25mg/kg均属合理添加量;当日粮中Zn、Cu添加水平分别在25～165mg/kg和10～25mg/kg时,Zn、Cu水平及其互作对免疫器官重量及其指数无显著影响。     

牛膝对肉鸡生产性能与免疫器官指数的影响

试验选择48羽12日龄快大黄肉仔鸡随机分成3组,在试验组的基础日粮中分别添加0%、0.4%和0.8%的牛膝,试验期30 d,研究牛膝对肉鸡生产性能与免疫器官指数的影响。结果表明,与对照组相比,Ⅰ组45日龄肉鸡平均日采食量、日增重显著提高(P<0.05),料重比显著降低(P<0.05);此外,与对照组相比,Ⅰ组30日龄法氏囊、脾脏指数,45日龄脾脏指数显著提高(P<0.05),Ⅱ组45日龄脾脏指数显著提高(P<0.05)。研究提示,合理使用牛膝不仅可以提高肉鸡的生产性能,还能有效促进免疫器官的生长发育,其适宜添加量为0.4%。     

锌和维生素C对热应激条件下肉鸡生长性能和免疫反应的影响

文章旨在研究日粮单独或联合使用锌和维生素C对高温条件下肉鸡生长性能和免疫反应的影响。试验选择320只1d肉仔鸡,根据体重随机分为4组,每组4个重复,每个重复20只鸡。对照组饲喂基础日粮(锌含量为40mg/kg),处理1组在基础日粮中添加60mg/kg锌,处理2组在基础日粮中添加200mg维生素C,处理3组在基础日粮中添加60mg/kg锌+300mg/kg维生素C,试验共开展35d。在试验第21~35天对鸡只进行热应激诱导,即25℃12h,25~34℃3h,34℃6h,34~25℃3h。结果显示:处理组较对照组均显著提高了肉鸡的采食量、体增重(P<0.05),显著降低了料比(P<0.05)。日粮同时添加锌和维生素C组肉鸡采食量和体增重最高(P<0.05)。与对照组相比,日粮添加60mg/kg锌、200mg/kg维生素C或锌和维生素C联合使用的肉鸡脾脏、胸腺和法氏囊重量显著提高(P<0.05)。60mg/kg锌+200mg/kg维生素C和200mg/kg维生素C组较对照组显著提高了新城疫、传染性法氏囊炎和传染性支气管炎的抗体滴度(P<0.05)。与对照组相比,60mg/kg锌+200mg/kg维生素C、200mg/kg维生素C组和60mg/kg锌组显著提高了血液白细胞总数、淋巴细胞和单核细胞占比(P<0.05)。结论:在本试验条件下,日粮单独或联合添加锌和维生素C均可显著改善热应激条件下肉鸡的生长性能和免疫状态。     

Effects of dietary betaine on growth performance,fat deposition and serum lipids in broilers subjected to chronic heat stress

We evaluated the effects of supplementing betaine on growth performance, fat deposition and lipid metabolism status in broilers kept under chronic heat stress. Five hundred and forty chicks were randomly divided into six groups and the two normal temperature groups were held at normal ambient temperature and fed the basal diet (CONT) and basal diet plus 0.1% betaine, respectively. Heat stressed (HS) broilers were held at 32 ± 1°C from days 22 to 42 and fed the basal diet containing variable levels of betaine. Broilers were examined at days 28, 35 and 42 for body weight, feed consumption, fat deposition and serum lipids. The CONT and betaine‐supplemented groups showed higher (P < 0.01 or P < 0.05) feed consumption, body weight gain, and lower feed : gain ratio compared with the HS‐CONT group. Meanwhile, heat stress increased abdominal, intermuscular and subcutaneous fat deposition, whereas the supplemental betaine significantly decreased those compared with the HS‐CONT group. Additionally, betaine supplementation significantly decreased triglyceride, free fatty acids, low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol compared with HS‐CONT. Chronic HS reduces broiler production performance. However, betaine can reverse these negative effects partially and thus improve carcass composition by changing lipid metabolism.     

氯化铵对肉仔鸡热应激的影响

通过离子平衡途径,在肉仔鸡日粮中添加氯化铵,观察其对家禽热应激的影响。将270只1日龄艾维茵肉雏鸡随机分为5个处理,每处理设3个重复,试验持续到5周龄。试验模拟夏季高温环境,全期人工控温28～35℃。1～28日龄进行饲养试验;29～34日龄进行代谢试验。5组试验日粮为:Ⅰ为正对照组,21%CP;Ⅱ为Ⅰ组日粮+0 62%氯化铵;Ⅲ为负对照组,19%CP;Ⅳ为Ⅲ组日粮+0 62%氯化铵;Ⅴ为Ⅲ组日粮+1 00%氯化铵。试验结果表明:Ⅱ、Ⅲ、Ⅳ和Ⅴ组肉仔鸡期末体重、日增重、采食量和饲料转化率与对照组无显著差异,Ⅴ组21日龄体重显著降低(P<0 05);Ⅱ和Ⅴ组显著提高CP、Ca和P的表观代谢率(P<0 05),Ⅴ组P除外;Ⅴ组粪便含水率明显增加(P<0 01);Ⅲ、Ⅳ组与对照组代谢指标差异不显著。     

Effect of arginine and threonine administered in ovo on digestive organ developments and subsequent growth performance of broiler chickens

This trial was conducted to investigate the effect of arginine (Arg), threonine (Thr) and Arg + Thr administered in ovo on growth performance, digestive organs and intestinal morphology in broiler chickens. On day 14 of incubation, 400 fertile eggs were randomly allotted to five experimental treatments through injection in the amniotic fluid including: (i) control (none injected), (ii) sham (0.5 ml of 0.5% saline), (iii) Arg (35 mg/egg), (iv) Thr (25 mg/egg) and (v) Arg + Thr (35 + 25 mg/egg). After hatching, chicks were given a commercial corn–soya bean diet up to 42 days of age. Daily feed intake (FI) and body weight (BW) of chicks were measured during different periods of the trial. Digestive organs were measured for their relative weight and intestinal length on days 11 and 42 of age. Intestinal morphometric traits were evaluated on day 11 of the experiment. Supplementing amino acids affected the performance of broiler chicks as Thr significantly increased FI and BW across starter, grower and finisher periods compared with sham and control (p < 0.05). Furthermore, Arg + Thr injection increased jejunal weight compared with control on day 42 (p < 0.05). Moreover, Arg inclusion led to the greatest villus height and crypt depth among treatments in duodenum (p > 0.05); however, amino acid supplemented groups had lower villus height than control in jejunum (p < 0.05). Negative correlations found between digestive organs related to day 11 of age containing pancreas (r = ?0.484; p = 0.030), duodenal (r = ?0.577; p = 0.007) as well as ileal lengths (r = ?0.471; p = 0.035) and FI of entire period. Otherwise, positive relationships were observed between duodenum (r = 0.580; p = 0.007) and ileum (r = 0.582; p = 0.007) weights on day 42 and FI of chickens across the entire phase. In conclusion, Arg and particularly Thr injection into amnion can improve FI and post‐hatch growth performance of chickens which may be mediated by the development of digestive organs.     

Effect of resveratrol on growth performance,rectal temperature and serum parameters of yellow‐feather broilers under heat stress

This study investigated the effect of dietary resveratrol supplementation on growth performance, rectal temperature, and serum parameters of yellow‐feather broilers under heat stress. A total of 480 yellow‐feather broilers (28‐day‐old) were randomly allotted to five groups with six replicates. A thermoneutral group (TN) (24 ± 2°C) received a basal diet and another four heat‐stressed groups (37 ± 2°C for 8 hr/day and 24 ± 2°C for the remaining time) were fed the basal diet or basal diet with 200, 350, and 500 mg/kg resveratrol for 14 consecutive days. The results revealed that resveratrol supplementation improved average daily gain (p = 0.001), and decreased (p < 0.05) rectal temperature from d 3 when compared with heat‐stressed group without resveratrol. In addition, supplementation with resveratrol at 350 or 500 mg/kg lowered (p < 0.05) the contents of corticosterone, adrenocorticotropic hormone, cholesterol, triglycerides, uric acid, malonaldehyde, and activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, increased (p < 0.05) the levels of triiodothyronine, the ratio of triiodothyronine to thyroxine, total protein, glutathione, and activities of alkaline phosphatase, total superoxide dismutase, catalase, and glutathione peroxidase, though with few fluctuation. In conclusion, supplementation with resveratrol can improve the growth performance by positively regulating serum metabolic parameters and alleviating tissue oxidant damage of broilers under heat stress.     

马杜霉素对肉仔鸡免疫器官发育影响的研究

为了探讨马杜霉素对肉仔鸡免疫器官的影响,试验选择体重相近的1日龄肉仔鸡200只,在日粮中分别不添加马杜霉素(Ⅰ组)和添加5.0 mg/kg(Ⅱ组)、7.5 mg/kg(Ⅲ组)、10.0 mg/kg(Ⅳ组)的马杜霉素,连续饲喂4周,测定各组雏鸡胸腺、脾脏、法氏囊指数。结果表明:5.0 mg/kg马杜霉素3周对肉仔鸡免疫器官发育有一定促进作用,但3周后呈现一定的抑制作用;用7.5 mg/kg和10.0 mg/kg马杜霉素饲喂1周即可抑制免疫器官的生长发育,其抑制作用能持续至停药后1周,但在停药3周后基本恢复正常。说明马杜霉素对肉仔鸡免疫器官发育的抑制作用呈现一定的量效和时效效应。     

Effect of dietary Lycium barbarum polysaccharide on growth performance and immune function of broilers

Lycium barbarum polysaccharide (LBP) is a traditional Chinese herbal medicine possessing many properties such as anti-oxidant and immunomodulation. This study was conducted to evaluate the clinical efficacy of LBP in broilers. A total of 240 newly hatched broilers were randomly allotted into 4 treatments with 6 replicates. Diets in 3 treatment groups were supplemented with 2, 4, and 8 g/kg LBP, respectively, based on the control diet. Lymphocytes isolated from broiler blood were used to detect immunoregulation function of LBP in vitro. Results in vivo showed that average daily feed intake (ADFI) and feed conversion ratio (FCR) in the 4 g/kg LBP group were decreased significantly (P < 0.05). Dietary 4 g/kg LBP significantly increased immune organ indexes of broilers at 21 d (P < 0.05). Moreover, levels of serum total protein, globulin, albumin, and lysozyme of broilers were higher in the 8 g/kg LBP group (P < 0.05). CD4⁺/CD8⁺ ratio in blood T cells was higher in the 4 g/kg LBP group (P < 0.05). Results in vitro suggested that 100 and 1,600 μg/mL LBP supplementation significantly promoted blood B and T lymphocyte proliferation of broilers, respectively (P < 0.05). TNF-α mRNA abundance was observably decreased in the lower LBP concentration groups (P < 0.05). In conclusion, LBP may possess the clinical efficacy for growth promotion and immunomodulation and could be used as an alternative for nutritive additive in broilers.     

二氢杨梅素对肉仔鸡生长性能、免疫器官指数及血液生化指标的影响

1日龄AA肉公雏300只,随机分为5个组,每组6个重复,每个重复10只鸡。试验Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组在基础日粮中分别添加0%、0.025%、0.05%、0.1%和0.25%的二氢杨梅素(DMY),研究DMY对肉仔鸡生长性能、免疫器官指数及血液常规理化指标等影响。结果表明:1)日粮中添加不同剂量的DMY对肉仔鸡日增重有提高的趋势,0.05%的DMY显著提高肉仔鸡饲料转化率(P<0.01);试验期间,各组试验鸡生长发育正常,各组织器官未见异常。2)0.05%DMY显著提高21d肉仔鸡法氏囊指数(P<0.05);3)0.25%DMY组显著降低21d肉仔鸡血清总蛋白、白蛋白含量,对球蛋白无显著影响;4)0.025%、0.05%DMY显著降低21d肉鸡血清谷丙转氨酶(GPT)活性(P<0.05,P<0.01),0.025%～0.1%剂量的DMY能显著降低42d肉鸡血清GOT活性(P<0.05);5)各剂量的DMY对21、42d肉鸡血清谷草转氨酶(GOT)无显著影响。