Buyse Kobe, Noten Noémie Van, Delezie Evelyne, Goethals Luc, Janssens Geert P J, Lourenço Marta
Institute for Agricultural, Fisheries and Food Research, Melle, Belgium.
Department of Veterinary and Biosciences, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
Front Vet Sci. 2022 Sep 16;9:996524. doi: 10.3389/fvets.2022.996524. eCollection 2022.
It is known that high doses of various tannins could impair broiler growth, and this seems to be linked to a lowered protein availability. However, effects on protein digestion under the influence of hydrolysable tannins were minimal in previous research and literature. Other possible proposed reasons to explain reduced growth are scarce. In this experiment we studied the effect of hydrolysable tannins on body allometry by using different feeding schemes throughout the rearing period. In total 112 individually reared male Ross 308 broilers received a 3-phase basal diet with chestnut wood extract (+: 2,000 mg/kg) or not (-: 0 mg/kg) (Tanno-SAN, Sanluc International NV, Belgium). This resulted in 2 groups during the starter period (S+, S-), 4 groups in the grower period (G++, G+-, G-+, G-) and 8 groups in the finisher period (F+++, F++-, F+-+, F+--, F-++, F-+-, F--+, F--). Similar to previous studies, growth reduction was also observed in this study. Effects were the largest in broilers that were given the tannins during the grower phase. At the end of each phase 8 broilers per group were euthanized and sampled. Liver, pancreas, pectoralis muscle, intestinal weights and intestinal length were recorded. The largest effects were seen on the intestine. Broilers that received tannins during the grower phase, had longer intestines at the end of the finisher period. Furthermore, histological differences between treatment groups were observed at the end of the grower period. Addition of tannins in the grower phase (G-+, G++) resulted in longer villi, whereas addition of tannins in the starter (G+-, G++) caused deeper crypts at the end of the grower phase, with the group (G-+) having the highest villi-to-crypt ratio. These results tentatively prove that tannins influence intestinal growth, both macroscopically as well as histologically. We hypothesize that the observed growth reduction with tannins could be the result of a changed energy and nutrient partitioning, i.e., more nutrients are directed to intestinal growth than for muscle growth.
已知高剂量的各种单宁会损害肉鸡生长，这似乎与蛋白质利用率降低有关。然而，以往的研究和文献中，关于可水解单宁影响下蛋白质消化的研究较少。其他可能用来解释生长减缓的原因也很稀缺。在本实验中，我们通过在整个饲养期采用不同的饲喂方案，研究了可水解单宁对身体异速生长的影响。总共112只单独饲养的雄性罗斯308肉鸡接受了一种3阶段基础日粮，添加（+：2000毫克/千克）或不添加（-：0毫克/千克）栗木提取物（Tanno-SAN，比利时Sanluc International NV公司）。这导致在育雏期分为2组（S+，S-），生长期分为4组（G++，G+-，G-+，G-），育肥期分为8组（F+++，F++-，F+-+，F+--，F-++，F-+-，F--+，F--）。与以往研究类似，本研究中也观察到了生长减缓。在生长期给予单宁的肉鸡中，影响最大。在每个阶段结束时，每组8只肉鸡被安乐死并取样。记录肝脏、胰腺、胸肌、肠道重量和肠道长度。对肠道的影响最大。在生长期接受单宁的肉鸡，在育肥期结束时肠道更长。此外，在生长期结束时观察到处理组之间的组织学差异。在生长期添加单宁（G-+，G++）导致绒毛更长，而在育雏期添加单宁（G+-，G++）在生长期结束时导致隐窝更深，其中（G-+）组的绒毛与隐窝比值最高。这些结果初步证明，单宁在宏观和组织学上都会影响肠道生长。我们假设观察到的单宁导致生长减缓可能是能量和营养分配变化的结果，即更多的营养物质被导向肠道生长而非肌肉生长。
