Responses of growth performance,antioxidant function,small intestinal morphology and mRNA expression of jejunal tight junction protein to dietary iron in yellow-feathered broilers

This study aimed to investigate the dose-effect of iron on growth performance,antioxidant function.intestinal morphology,and mRNA expression of jejunal tight junction protein in 1-to21-d-old yellow-feathered broilers.A total of 7201-d-old yellow-feathered maleb roilers were allocated to 9 treatments with 8 replicate cages of 10 birds per cage.The dietary treatments were consisted of a basal diet(contained 79.6 mg Fe kg^(-1))supplemented with 0,20,40,60,80,160,320,640,and 1,280 mg Fe kg^(-1)in the form of FeSO_(4)·7H_(2)O.Compared with the birds in the control group,birds supplemented with 20mg Fe kg^(-1)had higher average daily gain(ADG)(P<0.0001).Adding 640 and 1,280 mg Fe kg^(-1)significantly decreased ADG(P<0.0001)and average daily feed intake(ADFI)(P<0.0001)compared with supplementation of 20mg Fe kg^(-1).Malondialdehyde(MDA)concentration in plasma and duodenum increased linearly(P<0.0001),but MDA concentration in liver and jejunum increased linearly(P<0.05)or quadratically(P<0.05)with increased dietary Fe concentration.The villus height(VH)in duodenum and jejunum,and the ratio of villus height to crypt depth(V/C)in duodenum decreased linearly(P?0.05)as dietary Feincreased.As dietary Fe increased,the jejunal relative mRNA abundance of claudin-1 decreased linearly(P=0.001),but the jejunal relative mRNA abundance of zona occludens-1(ZO-1)and occludin decreased linearly(P?0.05)or quadratically(P?0.05).Compared with the supplementation of 20 mg Fe kg^(-1),the supplementation of640 mg Fe kg^(-1)or higher increased(P?0.05)MDA concentrations in plasma,duodenum,and jejunum,decreased VH in the duodenum and jejunum,and the addition of 1,280 mg Fe kg^(-1)reduced(P?0.05)the jejunal tight junction protein(claudin-1,ZO-1,occludin)mRNA abundance.In summary,640 mg of supplemental Fe kg^(-1)or greater was associated with decreased growth performance,increased oxidative stress,disrupted intestinal morphology,and reduced mRNA expression of jejunal tight junction protein.

Molecular cloning and ontogenesis expression of fatty acid transport protein-1 in yellow-feathered broilers

Fatty acid transport protein-1 （FATP-1） is one of the important transporter proteins involved in fatty acid transmembrane transport and fat deposition. To study the relationship between FATP-1 mRNA expression and fat deposition, chicken （Gallus gallus） FATP-1 sequence was first cloned by rapid amplification of cDNA ends （RACE）. Tissue samples of chest muscle, leg muscle, subcutaneous fat, and abdominal fat were collected from six male and six female broilers each, at 22 days, 29 days, and 42 days, respectively. The tissue specificity and ontogenesis expression pattern of the FATP-1 mRNA of yellow-feathered broilers was studied by real-time reverse transcription polymerase chain reaction （RT-PCR）, and the fat deposition laws in different tissues were also compared. A 2,488 bp cDNA sequence of chicken FATP-1 was cloned by RACE （GenBank accession no. DQ352834）, including 547 bp 3＇ end untranslated region （URT） and 1,941 bp open reading frame （ORF）. Chicken FATP-1 encoded 646 amino acid residues, which shared 83.9% and 83.0% identity with those of human and rat, respectively. The results of quantitative PCR demonstrated a constant FATP-1 mRNA expression level in the chest muscle and subcutaneous fat of both male and female broilers at three stages, whereas the expression level of the FATP-1 mRNA in the leg muscle at 42 days was significantly higher than that at 22 days or 29 days. In the abdominal fat of male broilers, the gene expression significantly increased with age, whereas the female broilers showed a dramatic downregulation of FATP-1 expression in abdominal fat at 42 days. This suggested a typical tissue-and gender-specific expression pattern of chicken FATP-1, mediating the specific process of fatty acid transport or utilization in muscle and adipose tissues.

Dietary L-theanine alleviated lipopolysaccharide-induced immunological stress in yellow-feathered broilers

L-theanine, a natural nonprotein amino acid with a high biological activity, is reported to exert anti-stress properties. An experiment with a 3 ? 2 factorial arrangement was conducted to investigate the effects of dietary L-theanine on growth performance and immune function in lipopolysaccharide(LPS)-challenged broilers. A total of 432 one-day-old male yellow-feathered broilers were randomly assigned to 3 dietary treatments(control, antibiotic and L-theanine diets) with 2 subgroups of each(6 replicate cages;12 birds/cage). Birds from each subgroup of the 3 dietary treatments were intra-abdominally injected with the same amount of LPS or saline at 24, 25, 26 d of age. Both dietary L-theanine and antibiotic improved(P < 0.05) the growth performance of birds before LPS injection(d 1 to 21). The effect of dietary L-theanine was better(P < 0.05) than that of antibiotic. Lipopolysaccharide decreased feed intake(FI) and body weight gain(BWG) from d 22 to 28(P < 0.05), BWG and feed to gain ratio(F:G) from d 29 to 56(P < 0.05), increased mortality in different growth periods(P < 0.05), elevated the levels of serum cortisol, a1-acid glycoprotein(a1-AGP), interleukin-6(IL-6) on d 24 and 25(P < 0.05), reduced immune organ indexes and contents of jejunal mucosal secretory immunoglobulin A(s Ig A) on d 28(P < 0.05). The decreased FI and BWG, as well as increased F:G and mortality in LPS-challenged birds, were alleviated by dietary L-theanine or antibiotic from d 29 to 56 and from d 1 to 56. Dietary L-theanine mitigated the elevated serum a1-AGP level on d 25, serum IL-6 concentration on d 24 and 26, and the decreased jejunal mucosal s Ig A content on d 28 of the LPS-challenged birds. The results indicated that L-theanine had potential to alleviate LPS-induced immune stress in broilers.

Dietary supplementation with pioglitazone hydrochloride and L-carnosine improves the growth performance,muscle fatty acid profiles and shelf life of yellow-feathered broiler chickens

The present study aimed to investigate the effects of dietary pioglitazone hydrochloride(PGZ)and L-carnosine(LC)supplementation on the growth performance,meat quality,antioxidant status,and meat shelf life of yellow-feathered broiler chickens.Five hundred broiler chickens were randomly assigned into 4 experimental diets using a 2×2 factorial arrangement with 2 PGZ supplemental levels(0 and 15 mg/kg)and 2 LC supplemental levels(0 and 400 mg/kg)in basal diets for 28 d.The feed-to-gain ratio decreased whereas the average daily gain increased with PGZ supplementation.Greater dressing per-centages,contents of intramuscular fat(IMF)in breast and thigh muscles,C18:3n-6,C18:1n-9 and monounsaturated fatty acid(MUFA)percentages of thigh muscle were observed with PGZ addition.Additionally,significant synergistic effects between PGZ and LC on the C18:1n-9 and MUFA contents were found.Supplementation with LC decreased drip loss,cooking loss and total volatile basic nitrogen,and increased the redness(a*)value,the superoxide dismutase and glutathione peroxidase activities in thigh muscles.Moreover,the malondialdehyde content decreased when diets were supplemented with LC,and there was a synergistic effect between PGZ and LC.Additionally,the mRNA abundance of lipogenesis-related genes,such as peroxisome proliferator-activated receptor y(PPARγ),PPARγco-activator 1αand fatty acid-binding protein 3,increased with PGZ supplementation,and relevant anti-oxidation genes,such as nuclear factor erythroid-2-related factor 2 and superoxide dismutase 1,were enhanced with LC supplementation.In conclusion,the results indicated that the supplementation of PGZ and LC could improve the growth performance,antioxidant ability,IMF content,and meat shelf life of yellow-feathered broiler chickens.

矮小型黄鸡新品系培育

通过杂交,将白羽肉鸡中的dw基因导入黄羽肉鸡,培育矮小型黄羽肉鸡新品系。经过10年的周密研究,进行了9个世代的选育,参选公鸡和母鸡分别为307羽和2728羽,公、母鸡选留率分别为3.6％和31.9％。dw基因已在群体中纯合,生产性能和遗传稳定性均获提高,共组建了家系182个,核心群量300羽左右,已形成了一个矮小型专门化品系,可为品系间配套杂交提供亲本。F9生产性能分别为:56日龄公母平均体重1531.3g,饲料报酬2.52:1,成活率95.1％;50％开产日龄184d,开产体重2254.8g,500日龄产蛋量180.8枚;43周龄蛋重60.5g,受精率88.3％,孵化率73.6％;成年体重:公鸡3082.4g、母鸡2561.2g;成年蹠长:公鸡7.8cm、母鸡6.7cm。

优质矮小型黄羽肉鸡饲料利用效率相关性状的遗传参数估计

以优质矮小型黄羽肉鸡作为研究材料,结合采食量自动测定设备记录的采食量和体重数据,对30个家系的1 158个个体的饲料利用效率相关性状进行遗传力估计,并分析其与生长性状、部分屠体性状的相关关系。结果表明,44～83日龄剩余采食量的遗传力为0.35,44～83日龄饲料转化比的遗传力为0.22,两者呈显著的表型和遗传相关（rp=0.66,rg=0.75）。对两者进行选择会对生长性状和部分屠体性状带来不同程度的间接选择反应。饲料转化比与日均采食量的遗传相关为0.44,剩余采食量与日均采食量的遗传相关程度更高,为0.75。如果单纯从降低采食量的角度考虑,选择低剩余采食量比选择低料重比的效果可能会更好。

hspA9基因5′侧翼区SNPs对矮脚黄羽肉鸡耐热性的影响

对矮脚黄羽肉鸡纯系hspA9基因5′侧翼区进行PCR测序和PCR–RFLP检测,将检测到的突变位点与矮脚黄羽肉鸡纯系5个耐热性状(T3、皮质酮、异嗜性粒细胞与淋巴细胞比率(H/L)、CD3+T细胞和CD4+T细胞)进行关联分析。结果表明:矮脚黄羽肉鸡纯系hspA9基因5′侧翼区有3个单核苷酸多态性(SNP)位点(C.–85C>A、C.–485G>A和C.–568G>A),根据C.–85C>A的酶切位点,这个基因可分为AA、AC、CC型;根据C.–485G>A的酶切位点,这个基因可分为GG、GA、AA型;根据C.–568G>A的酶切位点,这个基因可分为GG、GA、AA型;热应激状态下,C.–485G>A位点与皮质酮极显著相关(P<0.01),GG基因型个体的皮质酮值极显著高于GA基因型个体;常温状态下,C.–485G>A位点与T3显著相关(P<0.05),GA基因型个体的T3值显著高于AA基因型个体,C.–568G>A位点与T3显著相关(P<0.05),GG基因型个体T3值显著高于GA和AA基因型个体,C.–568G>A位点与CD4+T细胞极显著相关(P<0.01),GG基因型个体CD4+T细胞值显著高于AA基因型个体。C.–485G>A位点和C.–568G>A位点对鸡热耐受性有较大的影响,可望用于鸡抗逆性的分子标记辅助选择。

饮用酵母发酵菌液对矮脚黄肉鸡生长性能、消化酶活性和盲肠菌落结构的影响

本文以矮脚黄肉鸡为研究对象,探讨从不同日龄起分别饮用2种以酵母菌为主要活性成分的发酵菌液对肉鸡生长性能、消化酶活性和盲肠菌落结构的影响,为发酵菌液在肉鸡生产中的应用提供依据。选取1日龄健康矮脚黄肉鸡母鸡1 680只,随机分为6组,每组4个重复,每个重复70只鸡。抗生素对照组(A组)在基础饲粮中添加30 mg/kg维吉尼霉素,空白对照组(B组)饲喂基础饲粮,试验组(C、D、E和F组)饲喂基础饲粮,分别按2种发酵菌液、14和27日龄2个开始饮用日龄分为4个组,2种发酵菌液在饮水中的添加水平为饮水量的3%。试验期78 d。分别于26、56和78日龄测定肉鸡的生长性能、十二指肠内容物消化酶活性、盲肠内容物细菌多样性等指标。结果表明:1)与空白对照组相比,27~56日龄,27日龄起饮用发酵菌液2肉鸡的料重比显著降低(P<0.05);57~78和14~78日龄,14日龄起饮用发酵菌液1和发酵菌液2肉鸡的料重比显著降低(P<0.05)。2)与空白对照组相比,56日龄时,27日龄起饮用发酵菌液2肉鸡的十二指肠内容物淀粉酶活性显著升高(P<0.05);26和78日龄时,14日龄起饮用发酵菌液1肉鸡的十二指肠内容物胰蛋白酶活性显著升高(P<0.05)。3)78日龄时,14日龄起饮用发酵菌液2和27日龄起饮用发酵菌液1肉鸡的盲肠内容物细菌多样性指数显著高于空白对照组(P<0.05);饮用发酵菌液使肉鸡的盲肠内容物细菌群落结构趋于一致,且越到试验后期相似性越高。由此可见,14日龄起给矮脚黄肉鸡饮用以酵母菌为主要活性成分的发酵菌液,可改变盲肠微生物组成,提高胰蛋白酶活性,有效降低料重比,提高养殖效率。

优质黄羽肉鸡肉用性能测定及屠宰性状的关联性分析

以康达尔集团养鸡公司育种中心的黄羽优质肉鸡B系为素材,随机抽取80日龄鸡只公母各20只进行屠宰测定。结果表明:屠体多数性状间都存在着较高或中等偏上的表型相关;屠宰率、全净堂率与各项指标间相关程度较弱;胸肌率与各项指标间呈现弱的负相关或不相关。

矮小型肉鸡血浆极低密度脂蛋白浓度与腹脂性状的相关分析

以温氏育种公司黄鸡矮小型品系N30 1为材料 ,分析血浆VLDL浓度与腹脂性状间的关系 ,结果表明 :10周龄公母鸡血浆VLDL浓度的变异系数很大 ,分别为 4 9.86 %和 4 9.5 1% ;血浆VLDL浓度与脂肪性状间有较高程度的正表型相关 ,在公鸡中血浆VLDL浓度与皮脂重、皮脂率、腹脂重、腹脂率的表型相关系数分别为 0 .186 ,0 .117,0 .381和 0 .375 ,而在母鸡分别为 0 .2 2 8,0 .2 35 ,0 .2 5 8和 0 .2 5 2。血浆VLDL浓度可以作为矮小型鸡只体脂沉积性状的选种指标。

伊莎明星肉鸡(纯系)生产性能的研究

对伊莎明星肉鸡(纯系)的生产性能进行了测定研究,结果表明:6周龄体重B系显著大于A系(P<0.05),D、E系极显著大于C系(P<0.01),但A与B、C、D、E系间屠宰率,全净膛率及胸腿肌率无显著性差异(P>0.05);矮小型C系具有体重轻,占地面积小,产蛋率高,节约饲料,降低生产成本等优点;但其繁殖性能较差,主要与遗传、环境、营养等因素有关。

矮小基因用于黄羽肉鸡品系杂交的效果分析

鸡性连锁矮小基因(sex-linked dwarf gene,dw基因)纯合显性时可降低饲料消耗。试验选用A系黄羽肉鸡作为父本,含有dw基因的两系杂交黄羽肉鸡DYJ作为母本,开展三元杂交试验,并以快速型黄羽肉鸡(CON)为对照,评价dw基因用于黄羽肉鸡生产的杂交效果。试验组ADYJ和对照组CON各300只雏鸡同一日龄进舍,在相同饲养管理条件下饲养至7周龄出栏,饲养期间记录各周龄体重和饲料转化效率,出栏后全群称重并随机抽取两组公、母鸡各15只进行屠宰性能测定,并评价dw基因用于黄羽肉鸡杂交的经济效益。结果显示,CON组7周龄体重为1 623.3 g,试验组ADYJ为1 690.4 g,虽高于CON组,但差异不显著(P>0.05)。CON组7周龄料肉比为2.31,试验组ADYJ组为2.26,低于CON组。屠宰性能比较发现,ADYJ公、母鸡胸肌率分别为23.4%和24.2%,均极显著高于CON组公、母鸡的胸肌率(17.1%和18.3%,P<0.01);ADYJ公、母鸡半净膛率分别为77.6%和77.0%,均显著高于对照组(76.3%和74.9%,P<0.05);ADYJ公、母鸡屠宰率分别为87.4%和87.6%,均显著高于CON组(86.4%和86.0%,P<0.05);对照组与试验组公、母鸡的腹脂率与腿肌率差异均不显著。经济成本核算结果显示,ADYJ为9.65元/只,较CON组低0.33元/只。由此可见,dw基因用于黄羽肉鸡品系杂交可显著提高黄羽肉鸡的生产效益。