不同着色剂对肉鸡生长及脚胫着色的影响

本试验旨在探讨着色剂金闪闪及加丽红＋加丽黄的组合在等成本的基础上对肉鸡生长性能及脚胫着色程度的影响。试验选用396只艾维茵肉仔鸡,0~14日龄不使用色素,15日龄起随机分成2个处理,每个处理2个重复,每个重复99只。各处理组的基础日粮一致,试验分15~29日龄和30~43日龄2个阶段。处理1,日粮分别添加30ppm加丽黄＋45ppm加丽红和35ppm加丽黄＋54ppm加丽红;处理2,日粮分别添加1100ppm和1340ppm的金闪闪。试验结果表明,2个处理组的料肉比和日增重差异不显著,但处理1组鸡的脚胫着色程度明显优于处理2组,其色泽级别提高了1．45级,差异极显著（P＜0．01）。     

不同油脂对麻黄肉鸡生长性能、屠宰性能和肉品质的影响

试验旨在研究不同种类油脂对麻黄肉鸡生长性能、屠宰性能和肉品质的影响。选取42日龄的雄性麻黄肉鸡240只，随机分为3个处理，每个处理8个重复，每个重复10只鸡，按照日粮油脂种类来源分为大豆油组、猪油组、鸡油组，试验期42 d。结果表明：饲喂不同油脂对43～84日龄麻黄肉鸡的生长性能无显著影响；与猪油组相比，鸡油组肉鸡全净膛率提高(P<0.05)，腹脂率有降低趋势(P=0.062)；猪油组肉鸡胸肌pH24 h低于大豆油和鸡油组肉鸡(P<0.05)；与猪油组相比，饲喂鸡油降低了84日龄肉鸡腿肌pH24h(P<0.05)；与鸡油组相比，猪油组肉鸡腿肌屠宰后45 min肉色L*值有提高趋势(P=0.091)，大豆油组24 h肉色L*值均提高(P<0.05)；不同油脂对肉鸡腿肌剪切力、滴水损失、蒸煮损失未见显著影响；猪油组、鸡油组的毛利润较大豆油组分别提高6.48%和16.55%。由此可见，使用大豆油、猪油、鸡油饲喂42～84日龄麻黄肉鸡，对肉鸡生长性能无显著影响；使用大豆油的肉鸡肉品质最佳；使用猪油能节约饲养成本，但对肉品质有负面影响；使用鸡油能提高肉鸡屠宰性能降低腹脂沉...     

促生长型中草药添加剂对肉仔鸡生产性能的影响

选用1日龄健康艾维茵肉仔鸡,采用单因素完全随机化试验设计,研究在饲料中添加促生长型中草药添加剂对肉仔鸡生产性能的影响。试验共设3个处理组,每个处理纽4个重复,每个重复100只。对照组喂基础日粮,试验I组和试验II组分别在相同基础日粮中添加0．75％和1％的促生长型中草药添加剂。结果表明,促生长型中草药添加剂可使1日龄艾维茵肉仔鸡在48个饲养日内死亡率降低3．5个百分点,单位鸡只平均增重和料重比分别提高3．53％（P〈0．05）和4．35％（P〈0．05）。     

不同铬源在高添加水平下对肉仔鸡生长性能和组织铬含量的影响

0—3周龄从肉仔鸡日粮添加8mgCr／kg的5种铬源，一个对照组，统计日增重和日采食量，取肝脏、肾和胫骨测定铬含量。结果表明：①在高添加水平8mgCr／kg下，日粮添加铬对3周龄肉仔鸡生长性能的不良影响取决于铬源。CrY对3周龄肉仔鸡的日增重、日采食和料重比没有不良影响（P〉0．05），但是CrPic、CrNic、CrMet和CrCl3均对3周龄肉仔鸡有不同程度的不良影响，在高水平8mgCr／kg下分别使肉仔鸡的日增重显著下降8．06％，16．46％，9．06％，41．36％（P〈0．05）；CrMet显著增加肉仔鸡日采食11．33％，而CrCl3显著降低肉仔鸡日采食17．04％；CrNic、CrMet和CrCl3使肉仔鸡的料重比显著升高20％、22％、41．33％o可见CrMet和CrCl3影响最大，其次为CrNic和CrPic。2.8mgCr／kgCrCl3显著增加3周龄肉仔鸡的腹脂率63．01％（P〈0．05），其它4种铬源对3周龄肉仔鸡的腹脂率没有显著影响（P〉0．05），表明高添加的条件下有机铬对肉仔鸡腹脂蓄积的影响比无机铬小。②在高添加水平下，铬源对1—21日龄肉仔鸡的肝脏铬含量、肾脏铬含量、胫骨铬含量有极显著影响（P〈0．01）.     

益生康取代抗生素对肉仔鸡生产性能的影响

将6万只22日龄健康艾维茵肉仔鸡随机分成3组，分别为对照组、试验组1和试验组2．每组5个重复，每个重复为4000只鸡，对照组饲喂基础日粮 抗生素，试验组1饲喂基础日粮 0.1％益生康，试验组2饲喂基础日粮 0．15％益生康，进行25d生长试验，研究益生康取代抗生素对内仔鸡生产性能的影响。试验结果表明：益生康取代抗生素可以显著提高增重和成活率，降低料肉比。     

益生素“活精”对肉仔鸡生产性能影响的研究

试验采用单因子完全随机化设计，研究了乳酸菌，酵母菌混合物饲料添加剂“活清”对不同生长阶段肉仔鸡生产性能的影响。试验选用288只1日龄AA肉仔鸡，随机分成4个处理，分别为抗生素组，无抗生素加活清（0．3％）组，无抗生素加活清（0．5％）组，抗生素和加活清（0．3％）组，每个处理8个重复，每重复9只鸡。结果表明，抗生素加活清（0．3％）组的鸡死亡率最低；0－3周龄，4－6周龄，第7周龄，0－7周龄各时间的日增重，日采食量，饲料转化率均无显著差异（P＞0．05）；但抗生素加活清（0．3％）组0－3周龄与4－6周龄的日增重及料肉比均有高于其它3组的趋势。由此可见，在肉仔鸡生产中，活清可以作为抗生素的替代物。     

油脂类型和日粮能量对肉仔鸡生长性能和脂肪沉积的影响

本试验旨在研究油脂类型和日粮能量对肉仔鸡生长性能和脂肪沉积的影响.选取900只AA公鸡分为10个组,采用3×3两因子试验设计,饲养6周,统计各阶段生产性能(体重、日采食量、日增重以及料重比),同时测定腹脂率、肝脂率、血清甘油三酯和胆固醇含量,胸肌、腿肌以及排泄物中脂肪含量.结果表明,豆油组和鱼油组肉仔鸡的料重比比牛油组低(P<0.05);低、中、高能组料重比显著低于对照组(P<0.05).油脂类型对腹脂率的影响不显著,但呈现的趋势同样是多不饱和脂肪酸与饱和脂肪酸相比,可减少腹脂沉积;鱼油降低了腿肌脂肪含量(P<0.05).与对照组相比,低、中、高能组腹脂沉积均有显著性增加(P<0.05),但中能组高于高能组和低能组(P<0.000 1).排泄物中脂肪含量牛油组高于豆油组和鱼油组,3个能量水平组高于对照组(P<0.05).油脂类型和能量水平的互作对22～42 d肉仔鸡日采食量、血清甘油三酯含量以及1～4周龄肉仔鸡排泄物中脂肪含量均有显著性影响(P<0.05).由此可知,日粮中添加豆油和鱼油可以提高肉鸡的生产性能,减少脂肪浪费,但3种油脂对肉仔鸡腹脂率的影响无显著差异;能量为13.39 MJ/kg时肉仔鸡的日增重和日采食量最大;肉仔鸡脂肪的排出在饲养期的第5周达到最低.     

松科植物提取物对肉仔鸡生长和屠宰性能的影响

对从豫西山区野生松科植物松树皮中提取的生物活性物质用于肉仔鸡试验。选取1日龄艾维茵肉仔鸡300只,随机分为3组,每组4个重复。试验1组作对照,试验2和试验3组在肉仔鸡日粮中分别添加0.02%和0.04%松科植物松树皮提取物。经54 d饲喂试验,结果表明:试验2和试验3组的平均日增重、平均日采食量及饲料转化率均高于对照组(P<0.05),2组和3组间差异不显著(P>0.05);2和3组肉仔鸡死亡率分别下降40%和60%,成活率明显提高;各试验组间胸肌率、腹脂率、胸肌含水率、胸肌熟肉率没有显著差异(P>0.05),而2组和3组的腿肌率和胸肌pH值显著高于对照组(P<0.05)。     

不同日粮能量水平对肉仔鸡生产性能和屠宰性能的影响

为了研究不同能量水平日粮对21～45日龄艾维茵肉仔鸡生产性能和屠宰性能的影响,试验选择21日龄150只艾维茵肉鸡,随机分成3组,每组5个重复,每个重复10只鸡,在相同蛋白质水平下(19.50%),试验Ⅰ组、Ⅱ组和Ⅲ组肉仔鸡分别用12.50 MJ/kg、12.90 MJ/kg和13.30 MJ/kg的能量水平日粮饲喂,预试期为3 d,正试期为21 d,检测日增重、日采食量、料重比、胴体重、腹脂率、全净膛率、胸肌率以及腿肌率。结果表明:试验Ⅱ组和试验Ⅲ组的平均日增重、日采食量均显著高于试验Ⅰ组(P0.05),试验Ⅱ组和试验Ⅲ组间平均日增重、日采食量均差异不显著(P0.05),各组间料重比差异显著(P0.05);试验Ⅱ组和试验Ⅲ组的胴体重、腹脂率显著高于试验Ⅰ组(P0.05),试验Ⅱ组和试验Ⅲ组间胴体重、腹脂率差异不显著(P0.05),各组间全净膛率、胸肌率、腿肌率均差异不显著(P0.05)。说明日粮能量水平为12.90 MJ/kg时,肉鸡的生产性能和胴体性能表现较好。     

共轭亚油酸和鱼油组合对雄性肉鸡屠体性状、肌肉脂肪酸组成和脂质过氧化状态的影响

本试验旨在研究饲粮中同时添加共轭亚油酸(CLA)和鱼油对雄性肉鸡屠体性状、肌肉脂肪酸组成和脂质过氧化状态的影响。120只21日龄雄性爱拔益加(AA)肉仔鸡随机分配到4个组:豆油组(2%)、CLA组(2%)、鱼油组(2%)和混合组(1%CLA+1%鱼油)。每个组6个重复,每个重复5只鸡。42日龄屠宰取样。试验结果如下:混合组肉仔鸡的胸肌率和腿肌率与CLA组和鱼油组没有显著差异(P0.05)。CLA组、鱼油组和混合组肉仔鸡的腹脂率显著低于豆油组(P0.05)。鱼油组和混合组肉仔鸡胸肌中脂肪含量均显著低于CLA组(P0.05)。CLA组和混合组肉仔鸡的胸肌和腿肌中饱和脂肪酸含量均极显著高于鱼油组(P0.01),单不饱和脂肪酸含量显著低于鱼油组(P0.05)。鱼油组和混合组胸肌和腿肌中n-3多不饱和脂肪酸(n-3 PUFA)的含量,特别是C20∶5、C22∶5和C22∶6含量,均极显著高于CLA组(P0.01)。肉仔鸡胸肌和腿肌中C20∶5、C22∶5和C22∶6的含量在鱼油组和混合组之间没有显著差异(P0.05)。混合组肉仔鸡胸肌和腿肌的脂质过氧化水平均显著低于鱼油组(P0.05)。结果表明,CLA和鱼油在肉仔鸡胸肌和腿肌的不饱和脂肪酸尤其是n-3 PUFA的沉积和脂质稳定性方面有一定的互补作用。     

牛磺酸对酒精性脂肪肝大鼠脂肪代谢的影响

采用白酒灌胃及饲喂高脂饲料的方法建立大鼠酒精性脂肪肝病模型，探讨牛磺酸对酒精脂肪肝病大鼠脂肪代谢的影响。将40只Wister大鼠随机分为对照组（10只）、模型组（10只）、预防组（10只）和治疗组（10只），试验周期共为16周。检测牛磺酸干预后大鼠血清中的总胆固醇（TC）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）、甘油三酯（TG）、甲状腺激素（T3、T4）的含量，制作大鼠肝组织切片，观察病理学变化，从而研究牛磺酸的药理学效应。结果表明，牛磺酸可以有效降低大鼠血清中TC、LDL-C、TG、T4含量，提高大鼠血清中HDL-C、T3含量；牛磺酸能够减轻肝的病理损伤程度，表现为牛磺酸干预后大鼠肝细胞脂肪变性数量明显减少，脂肪空泡变性程度明显减轻。     

油脂的添加技术

随着饲料工业的发展，对饲料生产的要求也越来越高，除了要求生产一般的畜禽饲料外，还要求生产水貂、对虾、蟹、鳗鱼等特种动物的饲料；不仅要求生产粉状饲料，还要求生产颗粒饲料、膨化颗粒饲料等。为了提高生产水平，油脂添加技术已是目前饲料生产中的一个十分重要的课题。为了充分发挥油脂添加的作用，合理而经济地采用这项技术，并使之获得良好的效果，对近几年来饲料中油脂添加技术作一论述。１油脂的作用油脂的最主要作用是提供能量，除此之外具有以下作用。１．１额外能量效应主要是指添加油脂后，饲料的利用率提高。其原因可能是油…     

富锗酵母对高脂小鼠脂肪代谢的影响

试验选用60只健康的雄性小白鼠,完全随机地将其分成5组,即基础料组、高脂组和试验Ⅰ组、试验Ⅱ组、试验Ⅲ组,建立高脂模型。以高脂组为对照组,对试验Ⅰ组、试验Ⅱ组、试验Ⅲ组小鼠分别饲喂20、40、60 mg/kg三个浓度梯度的富锗酵母。测定不同剂量的富锗酵母下,对各组小鼠生长性能、脂肪和血清指标的影响。结果表明:在生长性能上,富锗酵母能不同程度降低料重比,提高日增重;在体脂方面,能极显著降低生殖器官周围脂肪的质量;在血清指标上,富锗酵母能不同程度降低小鼠血液中总胆固醇和甘油三酯的含量。富锗酵母对雄性高脂小鼠有一定的降脂和促进生长的作用。     

Expression of fat deposition and fat removal genes is associated with intramuscular fat content in longissimus dorsi muscle of Korean cattle steers

Intramuscular fat (IMF) in cattle is an important component of traits that influence meat quality. We measured carcass characteristics and gene expression in Korean steers to clarify the molecular mechanism(s) underlying IMF deposition in LM tissue by determining the correlation between IMF content and gene expression abundance and by developing models to predict IMF content using gene expression abundance. The deposition of IMF is determined by a balance between fat deposition and fat removal in the LM. We measured mRNA abundance of lipid metabolic genes including lipogenesis [acetyl CoA carboxylase (ACC), fatty acid synthase (FASN)], fatty lipid uptake [lipoprotein lipase (LPL), fatty acid translocase (CD36), fatty acid transport protein 1 (FATP1)], fatty acid esterification [glycerol-3-phosphate acyltransferase 1 (GPAT1), acylglycerol phosphate acyltransferase 1 (AGPAT1), diacylglycerol acyltransferase 1 (DGAT1), DGAT2], lipolysis [adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), monoglyceride lipase (MGL)], and fatty acid oxidation [carnitine palmitoyl transferase 1B, very long-chain acyl-CoA dehydrogenase (VLCAD), medium-chain acyl-CoA dehydrogenase (MCAD)] in the LM. The mRNA abundance of the GPAT1 gene showed the greatest correlation (r = 0.74; P < 0.001) with IMF content among 9 fat deposition genes. The gene expression abundance of other fat deposition genes including ACC, FASN, LPL, CD36, FATP1, AGPAT1, DGAT1, and DGAT2 also exhibited significant positive correlations (P < 0.05) with IMF content in the LM. Conversely, ATGL mRNA abundance showed the greatest negative correlation (r = -0.68; P < 0.001) with IMF content in the LM among 6 fat removal genes. The expression of other fat removal genes including MGL, VLCAD, and MCAD showed significant negative correlations (P < 0.05) with IMF content. Our findings show that the combined effects of increases in lipogenesis, fatty acid uptake, fatty acid esterification, and of decreases in lipolysis and fatty acid oxidation contribute to increasing IMF deposition in Korean steers. The multiple regression analysis revealed that the mRNA abundance of the GPAT1 gene in the LM was the first major variable predicting IMF content (54%) among 15 lipid metabolic genes. The second was mRNA abundance of ATGL (11%). In conclusion, these results suggest that GPAT1 and ATGL genes could be used as genetic markers to predict IMF deposition in the LM.     

Abdominal fat weight and thickness as predictors of total body fat in broilers

In two experiments broilers of both sexes from two strains were reared to 16 weeks of age to determine how total body fat could be estimated and predicted from some carcase traits. In the first experiment, age, carcase weight and abdominal fat thickness were found to be significant factors in the prediction of total body fat weight estimated from abdominal fat weight. In the second experiment abdominal fat weight was the best predictor of total body fat weight, obtained by ether extraction of the minced whole carcase. Inclusion of abdominal fat weight in the prediction equation after carcase weight and abdominal fat thickness significantly improved the regression. If the carcase cannot be weighed and abdominal fat weight is not available, because of the more laborious nature of its determination, then the measurement of abdominal fat thickness can be useful in predicting the total body fat content.     

Endogenous fat losses and true and apparent fat digestibility in adult and growing dogs fed diets containing poultry offal fat

The objective of this study was to evaluate the coefficient of total tract apparent digestibility (CTTAD) of dietary nutrients, endogenous fat loss (EFL), dietary metabolizable energy (ME) content, coefficient of true digestibility (CTD) of fat and faecal parameters of dogs. A total of 16 puppies and 8 adult dogs were distributed according to a double Latin square experimental design. A basal diet was formulated, to which increasing levels (60, 120 and 180 g/kg) of poultry offal fat oil were added. EFL was estimated using hyperbolic and linear regression as a function of LW/day and dry matter (DM) intake, respectively, and the CTD of fat was calculated. The CTTAD of acid-hydrolysis ether extract (AHEE) and ME content increased as dietary poultry offal fat level increased both in adult dogs and in puppies (p < .05). The CTTAD of DM and crude protein were higher in adult dogs than in puppies. EFL was estimated by hyperbolic regression as y = 98.1094 − 13.6202/x and y = 99.1280 − 26.1366/x, where y = CTTAD of AHEE (%) and x = AHEE intake/kg BW, for adult dogs and puppies, respectively, which yielded EFL values of 138 and 262 mg AHEE per kg BW per day for adult dogs and puppies respectively. The EFL estimated by linear regression was 7.89 g and 8.97 g/kg DM intake for adult dogs and puppies respectively. The CTD estimated by both methodologies was higher in puppies than in adults (p < .05). Lower faecal DM and score, and higher ammonia production were obtained in puppies than adult dogs (p < .05). The results indicate good fat utilization and that fat digestibility is underestimated, as the CTTAD of AHEE does not take into account EFL, particularly at low-fat inclusion levels and in growing dogs, which have greater EFL than adult dogs.     

Selection against abdominal fat percentage may increase intramuscular fat content in broilers

Excessive abdominal fat content (AFC) has negative impacts on feed efficiency and carcass quality. Unlike AFC, intramuscular fat content (IMFC) could be a favourable trait, which has a positive impact on meat quality. To meet consumers' needs, a long‐term goal of broiler breeders is to decrease AFC and improve the IMFC simultaneously. The current study was designed to investigate the relationship between AFC and IMFC and to compare IMFC, including the pectoral major muscle fat content (PIMFC) and intramuscular fat content of leg muscle (LIMFC), between two broiler lines divergently selected for abdominal fat percentage over 17 generations. The results showed that there was a significant difference in PIMFC and LIMFC between the two lines in all five generation populations used. The birds in the lean line had significantly lower AFC but higher PIMFC and LIMFC than the birds in the fat line. We also detected differences in the liver fat content (LFC) between the two lines and the results showed that birds in the fat line had significant higher LFC than birds in the lean line. Our results indicated that a desirable broiler line with higher IMFC but lower AFC could be obtained by genetic selection.