早期热应激对肉仔鸡后期生长发育的影响

旨在研究早期热应激对肉仔鸡后期生长发育及骨骼肌中相关信号通路基因表达的影响。本研究选取健康、体重相近的刚出壳AA肉仔鸡192只（公母各半）,随机分成2组（每组4个重复,每个重复24只鸡）,饲喂至3日龄时,分别给予36℃热应激处理24 h （热应激组）和正常温度（33℃）饲喂（对照组）。42日龄时每个处理选取8只鸡采取血浆,屠宰后测定胴体性能,分离胸肌样品测定骨骼肌发育有关的基因表达。结果表明,热应激当天肉仔鸡增重显著降低,但整个饲养期肉仔鸡的平均日增重显著增加（P<0.05）;与对照组相比,早期热应激有提高整个饲养期肉仔鸡平均日采食量的趋势（0<P<0.1）。早期热应激对肉仔鸡的屠宰率、半净膛重、全净膛重、肝比重、心比重、胸肌率、腿肌率、腹脂率都无显著影响（P>0.05）。早期热应激显著升高了42日龄肉仔鸡血浆酮体含量（P<0.05）。在胸肌中,早期热应激显著提高了胰岛素样生长因子（IGF-1）及其受体（IGF-1R）的基因表达（P<0.05）。本试验结果提示,早期热应激促进了肉仔鸡后期的生长发育,骨骼肌中IGF-1信号可能参与此调节过程。     

Behavioural and physiological responses of three chicken breeds to pre-slaughter shackling and acute heat stress

1. The aim of this study was to compare the behavioural and physiological responses to hanging and acute heat stress in three different chicken breeds. Chicks were obtained from a slow-growing French 'Label Rouge' line (SGL), a fast-growing standard line (FGL) and a heavy line (HL). The SGL, FGL and HL birds were slaughtered at their respective market ages of 12, 6 and 6 weeks, in an attempt to achieve similar body weights. Before stunning, birds were either shackled by their legs on the moving line for 2 min (shackling stress: SH) or placed in a room at 35 degrees C and 60% of humidity for 3.5 h and then shackled for 2 min (acute heat stress plus shackling: H + SH) or subjected to minimal stress by shackling for 10 s before stunning (control group: C). 2. Bird physiological responses to the three pre-slaughter treatments were estimated by measuring blood corticosterone, glycaemia, creatine kinase activity, acid-base status and electrolyte concentration as well as lactate content and glycolytic potential in the breast (Pectoralis major) and thigh (Ilio tibialis) muscles. Behavioural responses to shackling stress were evaluated by measuring wing flapping duration, straightening up attempts and vocalisations. 3. Blood corticosterone was higher in SH and H+SH groups than in the C group, regardless of genotype. The struggling activity on the shackle line differed among chicken breeds. It was more intense and occurred more rapidly after hanging in the SGL birds than in both other breeds. Furthermore, SGL struggling activity was not affected by hanging duration while it increased with hanging duration in FGL and HL birds. 4. Wing flapping duration was negatively correlated with blood pH, bicarbonate concentration and positively correlated with breast muscle lactate content, indicating that struggling stimulated antemortem glycolysis activity in breast muscle. Acute heat stress affected blood Ca2+ and Na+ concentration and increased glycaemia and glycolytic potential of thigh muscle. 5. Both acute heat stress and shackling before slaughter were experienced as stressful events by all types of birds.     

Metabolic rate and its relationship with ascites in chicken genotypes

1. Male chickens of 7 genetic lines, consisting of two pure sire and two pure dam populations, a commercial broiler cross and two slow-growing chicken lines (Label Rouge, LR and Mechelse Koekoek, MK) were reared from 1 to 37 d of age. The chickens received a two-phase dietary regime and were subjected to low ambient temperature. 2. The experimental aim was to investigate relationships between susceptibility to ascites and heat production. 3. Body weight gain (BWG), food intake and food conversion ratio (FCR) were determined. Ascites mortality, arterial pressure index (API=right ventricular/total ventricular weight ratio), haematocrit values, proportional lung weight (lung weight/body weight x 100), plasma thyroid hormones (thyroxine, T4 and triiodothyronine, T3) and arterial blood gas pressures (pCO2 and pO2) were determined. The heat production per kg metabolic body weight (H/W0.75) and total heat production (H) were calculated for the period 16 to 33 d using an energy balance study according to the comparative slaughter method. 4. The two breeder sire lines had high BWG and low FCR and high but different incidences of ascites compared with the slow-growing ascites resistant LR and MK lines with notable high FCR. The broiler cross and slower-growing breeder dam lines had a similar and relatively lower incidence of ascites mortality. 5. The fast-growing chickens had low H/W0.75 values compared with slow-growing lines. 6. These fast-growing breeder sires had lower plasma thyroid hormone, reduced proportional lung weights, low arterial pO2 and high arterial pCO2 pressures compared with the slower-growing lines. 7. In conclusion, ascites incidence was associated with lower heat production per metabolic body weight and therefore a lower oxygen requirement per metabolic weight.     

母体日粮低能量对后代肉仔鸡生长性能、胴体品质和肉质的影响

本文旨在研究母体日粮低能量对后代肉仔鸡生长性能、胴体品质及肉质的影响.试验选用低脂系肉种鸡120羽,随机分成2组,每组60个重复,每个重复1羽,即单笼饲养.在肉种鸡产蛋期产蛋率达到5%进行试验处理,试验分试验组和对照组,试验组代谢能量为对照组的80%孵化后的肉仔鸡按照母体不同能量处理各挑选健康仔鸡,在相同的试验条件下进行饲养,试验期为56 d.结果表明:1)与对照组相比,母体日粮低能量有降低1日龄肉仔鸡体重的趋势,对全期日增重和料重比影响不显著(P＞0.05);2)与对照组相比,母体日粮低能量对后代肉仔鸡胸肌和腿肌的水分、脂肪和蛋白质含量,胸肌率和腹脂率均无显著影响(P＞0.05),但显著增加腿肌率(P＜0.05);3)与对照组相比,母体日粮低能量对后代肉仔鸡胸肌和腿肌的pH、红度、黄度、滴水损失和蒸煮损失均无显著影响(P＞0.05),但pH、红度和黄度值有升高趋势,滴水损失和蒸煮损失有降低趋势,胸肌和腿肌剪切力显著降低(P＜0.05);4)与对照组相比,母体日粮低能量显著提高后代肉仔鸡胸肌和腿肌肌纤维密度(P＜0.05),显著降低后代肉仔鸡胸肌和腿肌肌纤维直径(P＜0.05).本试验的研究结果表明:母体日粮低能量对后代肉仔鸡的胴体品质及肉质能产生一定的影响.     

Quantitative trait locus detection in commercial broiler lines using candidate regions

A QTL that explained a large proportion of the phenotypic difference between broiler and layer chickens in an experimental cross was evaluated in a commercial broiler line. A three-generation design, consisting of 15 grandsires, 608 half-sib hens, and more than 50,000 third-generation offspring, was implemented within the existing breeding scheme of a broiler breeding company. Four markers from a candidate region on chicken chromosome 4 were selected for their informativeness in the grandsires and used to genotype the first two generations. Using half-sib analyses, linkage was studied between these markers and 13 growth and carcass traits. The QTL analyses confirmed the presence of significant QTL for body weight (P < 0.01) and residual feed intake (P < 0.05) on chicken chromosome 4. Furthermore, evidence was found for QTL affecting the relative weight of bone and muscle in the thigh. Four more markers were added to increase resolution of the QTL positions. This increased the significance of the QTL for body weight (P < 0.001) and residual feed intake (P < 0.01) and showed evidence (P < 0.05) for additional QTL affecting carcass weight and conformation score. This study showed for the first time that a QTL that explains differences between broilers and layers was segregating in lines that have been selected for body weight over 50 generations. A possible explanation could be a pleiotropic or closely linked effect on fitness-related traits that are not part of the present study. The results demonstrate the feasibility of QTL detection and the potential for marker-assisted selection within a commercial broiler line without altering the existing breeding scheme.     

Skeletal muscle damage following halothane anaesthesia in the domestic fowl: plasma biochemical responses.

The effects of a short period (10 minutes) of halothane anaesthesia upon skeletal muscle have been examined in broiler chickens. Integrity of the muscle membrane was assessed by measurement of plasma activities of intracellular enzymes. Creatine kinase activity was greatly increased during the first 12 hours post-anaesthesia and remained elevated for at least 48 hours. Lactate dehydrogenase activity exhibited a similar pattern which was less pronounced. Halothane anaesthesia induced transient hypercapnic acidosis and hypokalemia and increased corticosterone secretion but there was no significant effect upon deep body temperature. It is proposed that halothane may act directly upon skeletal muscle, perhaps influencing intracellular calcium homeostasis, to alter membrane permeability and increase enzyme efflux reflecting a degree of post-anaesthetic muscle damage. The transient changes in electrolyte and acid-base balance may contribute to these effects. Precautions should be taken to minimise the incidence or extent of halothane induced myopathy in birds particularly in rapidly growing broiler chickens where susceptibility may be increased.     

Responses to heat stress in commercial and local broiler stocks. 2. Developmental stability of bilateral traits.

1. Developmental stability of bilaterally symmetrical traits was measured in two fast (G1 and G2) and one slower growing (G3) broiler stocks when conditioned (chicks exposed to 36 degrees C for 24 h at 5 d of age) or food restricted (food withdrawn 2 h before the hot period and chicks fed between 17.00 and 08.00 h) during heat stress administered daily from 28 to 49 d of age. 2. Length of face, length, width and weight of shanks, weights of P. major and P. minor muscles, and weights of lung and caeca were chosen as bilateral traits representative of skeletal, muscle, respiratory and digestive systems. 3. Development of skeletal bilateral traits was affected primarily by genotype and sex. The heart:lung ratio decreased with conditioning in stocks G1 and G2 at 21 d. Face length, shank length and shank weight exhibited antisymmetry, whereas shank width and weights of P. minor, lung and caeca exhibited fluctuating asymmetry and antisymmetry. For P. major weight, there was directional asymmetry. 4. In general, relative asymmetry of skeletal traits was lower than for traits associated with muscle and with respiratory and digestive systems. Relative asymmetry of P. major weight was lower in conditioned and G3 broilers than in their respective counterparts. 5. If relative asymmetry is a valid indicator, item heat stress may be less in slower growing and conditioned broilers.     

热应激下鸡肝脏SFRP1和PDK4基因表达水平研究

为研究热应激条件下,鸡SFRP1和PDK4两个与代谢相关的基因在鸡肝脏组织中的差异表达,选取12只60日龄体重相近的黄羽肉母鸡,分为正常对照组(CL)、热应激反应组(HS)和热应激反应后的降温组(HF)3个处理组,并对这两个基因在三组肝脏组织中的表达水平进行荧光定量表达分析。结果表明,在热应激状态下,SFRP1和PDK4基因在肝脏中的表达均上调,且PDK4在对照组和热应激组间差异显著(P<0.05)。本研究结果还表明,当热应激反应后温度重新降至(25±1)℃时,SFRP1和PDK4在肝脏中的相对表达量均有不同程度的恢复,进一步说明这两个基因在热应激中发挥的作用。本研究为从分子机制分析热应激提供了相应的参考。     

Association of single nucleotide polymorphism of chicken uncoupling protein gene with muscle and fatness traits

Uncoupling proteins (UCPs) are in the mitochondrial inner membrane and belong to the transporter family. The biological function of UCPs is regulating discharge of proton gradient generated by the respiratory chain. As a result, the production of ATP is diminished, and dissipative heat is yielded. The present study was designed to investigate the association of UCP gene with chicken growth and body composition traits. The ninth generation of the broiler lines divergently selected for abdominal fat was used as a research population. Primers for UCP gene were designed from chicken genomic sequence. A single-nucleotide polymorphism, in the exon3 (T1316C) of UCP gene was detected by the polymerase chain reaction and restriction fragment polymorphism (PCR-RFLP) method. The UCP polymorphism was associated with muscle and fatness traits, such as pectoralis minor weight and abdominal fat weight. The results indicated that UCP gene could be a candidate locus or linked to a major gene which affects muscle and fatness traits in chicken.     

Effects of heat stress on growth, some blood variables and lipid oxidation in broilers exposed to high temperature at an early age

1. This study was conducted to determine metabolic and physiological responses of 2 commercial broiler strains, Hubbard (H) and Cobb (C), exposed to an ambient temperature of 38 degrees +/- 1 degree C for 2 h at 14 and 15 d of age. 2. Exposure to high temperature at an early age resulted in weight loss in strain C, which was not compensated for by 35 d of age but there was no weight loss in strain H. 3. Exposure of broilers to heat stress (38 degrees +/- 1 degree C) at 35 d of age resulted in an increase in rectal temperature, regardless of previously high temperature experience but acid-base balance and haematocrit values were not affected by heat stress. 4. Malondialdehyde concentration was higher in unexposed birds than in previously exposed ones and did not significantly differ between strains.     

Heritability and genetic correlation estimates for performance,meat quality and quantitative skeletal muscle fiber traits in broiler

Broiler feed efficiency and meat quality are the primary factors considered by the poultry industry. This study was conducted to estimate heritability and genetic correlation coefficients for skeletal muscle fiber number, area and diameter and performance and meat quality traits of Pectoralis major in a single male broiler line. (Co) variance components were estimated by restricted maximum likelihood method, using the software MTDFREML. The numerator relationship matrix was composed by 77,474 individuals. Heritability coefficient estimates ranged from moderate to high for juvenile BW, breast weight, ultrasound record of pectoral muscle, lightness and thawing meat loss. Genetic correlation estimates for performance and skeletal muscle fiber traits indicated that selection for higher breast weight and juvenile BW could reduce muscle fiber number and increase muscle fiber diameter and area, which could prejudice the meat quality of this line. Selection for muscle fiber number and against muscle fiber diameter and area might improve meat water retention ability and tenderness in this broiler line, and selection programs could consider those traits as selection criteria, although this may be costly. We recommend the evaluation of the indirect selection caused by the use of the performance traits as selection criteria especially for juvenile BW and breast weight. Direct, intense selection for both traits might be unfavorable for most of the meat quality traits analyzed, which could lead to losses to both the chicken meat processing industry and consumers.     

Variations in chicken breast meat quality: implications of struggle and muscle glycogen content at death

1. Pectoralis major (P. major) muscle pH and meat quality traits were studied in relation to bird response to ante-mortem stress in three chicken lines: a fast-growing standard line (FGL), a slow-growing French 'Label Rouge' line (SGL) and a heavy line (HL). Ninety-nine birds of the three genetic types were slaughtered at their usual marketing age (6, 12 and 6 weeks for FGL, SGL and HL birds, respectively) on the same day. The birds of each line were divided into three different ante-mortem treatment groups: minimum stress (shackling for 10 s) (C), shackling for 2 min (SH) and acute heat plus shackling stress (exposure to 35 degrees C for 3.5 h and shackling for 2 min before stunning) (H + SH). 2. Regardless of chicken line, wing flapping duration (WFD) between hanging and stunning was strongly negatively related to P. major muscle pH at 15 min post-mortem. It was also moderately negatively related to P. major muscle glycolytic potential (GP), which represents glycogen level at death. Increasing WFD induced an increased ultimate pH (pHu) only in HL. The consequences of increased WFD for breast meat traits were dependent on the chicken line: it induced lower L* and b* and higher a* and drip loss in SGL while it only increased breast a* in HL birds. By contrast, WFD variations did not alter breast meat quality traits of FGL birds. Regardless of the chicken line, increased GP was associated with lower pHu and higher L* and drip loss. In SGL, it also increased b* and decreased curing-cooking yield of breast meat. 3. Struggling activity on the shackle line and muscle glycogen content at death could partly explain line and pre-slaughter variations in breast meat pH and quality traits. The water holding capacity of the raw and cooked meat was impaired by long shackling in the case of SGL birds while it was barely affected by ante-mortem conditions in the two standard lines. In conditions which minimised bird struggling (C), SGL and FGL birds had meat with a better water holding ability than that of broilers from the heavy line. However, when broilers were subjected to SH or H + SH conditions, the breast meat water holding capacity of SGL birds was lowered to the same level as that of the heavy line birds.     

不同鸡种胚胎腿肌差异表达mRNA和lncRNA的筛选及其竞争性调控网络的构建

旨在筛选藏鸡和大恒肉鸡胚胎期骨骼肌差异表达的mRNA和lncRNA,并构建lncRNA-miRNA-mRNA竞争性调控网络,为进一步探讨两个鸡品种骨骼肌生长发育速度的差异机制奠定基础。随机选取已孵化18 d的藏鸡和大恒肉鸡胚胎各3个,采集胚胎腿肌组织进行转录组测序。筛选两个品种中差异表达的mRNAs和lncRNAs,对差异表达基因进行GO和KEGG富集分析,并对lncRNA的靶标miRNA以及靶向mRNA的miRNA进行预测,筛选与肌肉发育相关的mRNA和lncRNA构建lncRNA-miRNA-mRNA竞争性调控网络,最后利用实时荧光定量PCR (qRT-PCR)对测序结果进行验证。结果显示,共有106个mRNAs在两个品种中差异表达,其中上调表达mRNAs 48个,下调表达mRNAs 58个。差异表达lncRNAs共有28个,其中10个上调,18个下调。差异表达mRNA的GO富集结果显示,骨骼肌细胞分化条目被显著富集,KEGG富集分析中脂质代谢通路被显著富集。lncRNA靶基因的KEGG富集结果显示,在10个显著富集通路中,有基因显著富集于类固醇生物合成和脂肪酸生物合成等与脂质代谢...     

肉鸡品种对胴体性状和肉质的影响

本研究将清远麻鸡的两个纯系（A和B）与快速生长型AA肉鸡（C）杂交,在3个月的生长时间中测定了杂交品对肉鸡胴体性状、肌肉成分及氨基酸组成的影响。结果：杂交品系肉鸡的体重、屠体重、半净膛重、全净膛重、胸肌和腹脂重量均显著高于纯种品系（P＜0.05）。杂交品系肉鸡的肌纤维密度和剪切力较纯种品系显著提高了6.94%和7.98%（P＜0.05）。肉鸡品系对胸肌粗脂肪、肌苷酸、干物质、水分和粗蛋白质含量的影响均无统计学意义（P＞0.05）。结论：杂交后代的大多数胴体性状高于纯种,各品系的剪切力、肌纤维密度和肉质性状均相似。     

Limited effect of intense genetic selection for broiler traits on ovarian function and follicular sensitivity in broiler breeders at the onset of lay

Female chicks from 6 pure lines of broiler breeders were obtained from international broiler breeder companies. The lines were from three female and two male lines and a relaxed selection line derived from one of the male lines (M2) and maintained without selection for 25 years (generations). Replicate groups from each line were reared in floor pens and fed ad libitum. An additional group of the M2 male line was feed restricted and housed in similar pens. Twenty birds from each group were photostimulated after housing them in individual cages at 14 weeks of age. Ovarian follicular dynamics and follicular sensitivity were determined after the onset of lay. Female lines had a greater proportion of atretic follicles and more groups of multiple follicles than male lines. Body weights, fatness and age at puberty were similar in male and female lines. The relaxed selection line had more abdominal fat than any of the selected lines and the ovary contained a similar number of normal yellow follicles as the selected male line. Feed restriction decreased body weight, the numbers of yellow follicles, multiple yellow follicles and the proportion of atretic yellow follicles, and increased the age at onset of lay. The response of ovarian follicles of three different sizes to exogenous gonadotrophin stimulation with PMSG was similar in small yellow follicles, 5 to 6 and 2 to 3 mm white follicles in a female line, a male line and its relaxed line fed ad libitum. The results suggest that the original lines from which modern male-line broiler stocks are derived had a relatively large number of yellow follicles and a high propensity for multiple ovulation at the onset of lay. Separate selection for different traits in male and female lines has not had a dramatic effect on ovarian function or sensitivity to gonadotrophin stimulation.     

不同品种白羽肉鸡肌肉品质及营养成分的比较研究

为研究小型白羽肉鸡与快大型白羽肉鸡肌肉品质及营养成分差异,试验选取WOD168配套系为小型白羽肉鸡代表,选取科尼什与白洛克杂交后代为快大型肉鸡代表,于6周龄屠宰后进行肉品质及肌肉营养成分测定.结果显示:小型白羽肉鸡比快大型肉鸡有更高的剪切力,更小的肌纤维直径和更高的肌纤维密度;小型白羽肉鸡胸肌粗蛋白含量较快大型肉鸡高,...     

Peripheral leptin effect on food intake in young chickens is influenced by age and strain

The acute effect of leptin on the regulation of food intake was investigated in layer and broiler chickens. In an initial study, we observed that a single intraperitoneal injection of recombinant chicken leptin (1 mg/kg BW) dramatically reduced (38%) food intake in 56-day-old layer chickens, more moderately reduced (15%) food intake in 9-day-old layer chicks, and had no significant effect in 9-day-old broiler chicks. In a subsequent study, body weight and plasma concentrations of leptin were measured weekly in layer and broiler chicks from day 1 to 35 of age and brain leptin receptor and neuropeptide Y (NPY) mRNA expression were analyzed at 1, 9, and 35 days of age. At day 1 of age, peripheral concentrations of leptin were significantly greater in layer than broiler chicks. Subsequently, despite increases in body weight and differences in growth rates between layer and broiler chicks from day 8 to day 35 of age, peripheral concentrations of leptin were constant and similar in both genotypes. Leptin receptor and NPY mRNA were expressed in brain from day 1 in chicks of both genotypes and increased significantly to day 35 of age. These observations provide evidence that the inhibitory effect of leptin on the regulation of food intake in growing chicks is an age dependent process. Furthermore, acquisition of the anorectic effect of leptin is likely to be associated with greater expression of the leptin receptor and NPY mRNAs than to changes in blood levels of leptin. Finally, this study provides evidence that chickens selected for high growth rates may be less sensitive or responsive to peripheral concentrations of leptin than chickens with low growth rates (layers), suggesting that the faster growth of broiler chicks may be related to a lessened responsiveness to anorexigenic factors.     

不同日龄乌蒙凤鸡体尺与屠宰性能相关性与主成分分析

为研究乌蒙凤鸡的生长发育和生产性能,实验选择210、240、270、300日龄乌蒙凤鸡各60只(公母各半)进行体尺与屠宰测定,同时对其体尺与屠宰性能进行相关性与主成分分析.结果 表明:不同日龄公鸡的龙骨长、胸宽、胸深和骨盆宽存在极显著差异,不同日龄母鸡的胸宽、胸深和骨盆宽存在极显著差异.心脏重在210日龄与300日龄乌...     

倒毛鸡生物学特性、屠宰性能及肉质性状研究

为保护贵州地区倒毛鸡的种质资源和遗传多样性,研究其生长性能和肉用价值,试验对倒毛鸡的生物学特性、屠宰性能及肉品质进行了测定。结果表明:倒毛鸡的蛋重为(42.75±2.18)g,孵化率约为75%。倒毛鸡在0日龄时,公、母鸡之间的体重差异不显著(P0.05),30日龄后差异达显著水平(P0.05),180日龄平均体重公鸡为1 776.12 g、母鸡为1 455.68 g,差异显著(P0.05)。180日龄腹脂率母鸡高于公鸡,而活重、屠体重、半净膛重、全净膛重、胸肌重、腿肌重、屠宰率、全净膛率、腿肌率等性状指标公鸡优于母鸡,差异均显著(P0.05);其他性状指标在性别间差异不显著。公、母鸡腿肌p H值和剪切力均高于胸肌,失水率低于胸肌,公、母鸡之间差异均不显著(P0.05)。品尝实验显示,倒毛鸡肉质细嫩、味道鲜美,比普通土鸡更受欢迎。结论:倒毛鸡具有较好的肉用性能,有较大开发价值和发展前景。     

Cellular immune response in the small intestine of two broiler chicken lines orally inoculated with malabsorption syndrome homogenates

We studied the cellular immune response against malabsorption syndrome (MAS) in two broiler chicken lines, A and B. We determined the number of pan T-lymphocytes (CD3), helper T-lymphocytes (CD4), cytotoxic T-lymphocytes (CD8) and macrophages/monocytes in the small intestine in the first 2 weeks after oral inoculation of two MAS homogenates, MAS80 and MAS97-1. The immune cells were detected on cryostat tissue by immunohistochemistry and counted by villus area. In trial 1, we compared the two broiler lines for weight gain depression, intestinal lesion and number of CD3, CD4, CD8 cells and macrophages/monocytes after MAS80 inoculation. Although there was no significant difference in weight gain depression between the two broiler lines, line B had significantly higher numbers of CD8+ T-cells per villus area than had line A. To confirm part of the results of trial 1, trial 2 was done in which we compared different homogenates in broiler line B. Broiler line B was orally inoculated with either MAS97-1, intestinal homogenate obtained from healthy chickens (healthy homogenate), or phosphate buffered saline (PBS). In this trial, the MAS97-1 homogenate also induced weight gain depression and intestinal lesions, whereas the "healthy homogenate" and PBS did not induce weight gain depression or intestinal lesions. The broilers inoculated with MAS97-1 homogenate had significantly more CD8+ T-cells per villus area than had broilers inoculated with "healthy homogenate" or PBS. Increased CD8+ T-cells per villus area in the affected small intestines of broilers suggests an increase of cytotoxic T-cell activity.