Unité de Recherches Avicoles, Institut National de la Recherche Agronomique (INRA), 37380 Nouzilly, France.
Animal. 2010 Nov;4(11):1861-72. doi: 10.1017/S1751731110001266.
D+ (high digestion efficiency) and D- (low digestion efficiency) genetic chicken lines selected for divergent digestion efficiency were compared in this experiment. Gizzard functions were tested in terms of digesta mean retention time and reactions to high dilution of a corn diet with 15% coarse sunflower hulls. The corn standard (S) and high fibre (F) experimental diets were given from 9 days of age to chickens from both lines. Besides the measurements of growth efficiencies (9 to 20 days), digestibilities (20 to 23 days) and gut anatomy (0, 9, 29, 42 and 63 days), two digestive transit studies were performed at 9 and 29 days of age. For the transit studies, the S and F diets were labelled with 0.5% TiO2 and 1% Cr-mordanted sunflower hulls. These diets were fed ad libitum during 3 days, and then the birds were euthanized. The digestive contents were analysed for the determination of marker concentrations and mean retention times (MRTs) in digestive compartments (crop + oesophagus, proventriculus + gizzard, duodenum + jejunum, ileum, rectum + cloaca and caeca) were determined. D+ birds were confirmed as better digesters than D- birds during the growth period, in association with larger gizzard and pancreas, and lighter small intestine in D+ than in D-birds. The MRT in the proventriculus-gizzard system, higher in D+ than in D- birds, was a major factor associated with differences between D+ and D- birds regarding digestion efficiencies and gut anatomy. Diet dilution with fibres reduced differences in digestion efficiencies and proventriculus-gizzard MRT between lines. Differences in gut anatomy between lines tended to disappear after 8 weeks of age. In conclusion, this study showed that MRT in the proventriculus-gizzard system was a major factor associated with genotype differences between the D+ and D- genetic chicken lines selected for divergent digestion efficiency, with longer MRT found in D+ than in D- birds.
本实验比较了为不同消化效率而选育的D+（高消化效率）和D-（低消化效率）遗传品系鸡。通过食糜平均滞留时间以及对含15%粗向日葵壳的玉米日粮进行高稀释的反应来测试砂囊功能。从9日龄起，给两个品系的鸡投喂玉米标准（S）日粮和高纤维（F）实验日粮。除了测量生长效率（9至20日龄）、消化率（20至23日龄）和肠道解剖结构（0、9、29、42和63日龄）外，在9日龄和29日龄时进行了两项消化转运研究。对于转运研究，S和F日粮分别用0.5%二氧化钛和1%铬媒染向日葵壳标记。这些日粮自由采食3天，然后对鸡实施安乐死。分析消化内容物以测定标记物浓度，并确定消化腔室（嗉囊+食管、腺胃+砂囊、十二指肠+空肠、回肠、直肠+泄殖腔和盲肠）中的平均滞留时间（MRT）。在生长期间，D+鸡被证实比D-鸡消化能力更强，这与D+鸡的砂囊和胰腺更大、小肠比D-鸡更轻有关。腺胃-砂囊系统中的MRT，D+鸡高于D-鸡，这是D+和D-鸡在消化效率和肠道解剖结构方面存在差异的主要相关因素。用纤维稀释日粮可减少品系间消化效率和腺胃-砂囊MRT的差异。品系间肠道解剖结构的差异在8周龄后趋于消失。总之，本研究表明，腺胃-砂囊系统中的MRT是与为不同消化效率而选育的D+和D-遗传品系鸡之间基因型差异相关的主要因素，D+鸡的MRT比D-鸡更长。
