School of Environmental and Rural Science, University of New England, Armidale, 2351 NSW, Australia.
Nutrition and Care, Animal Nutrition, Evonik (SEA) Pte. Ltd., 609927 Singapore.
Poult Sci. 2020 Apr;99(4):2048-2060. doi: 10.1016/j.psj.2019.11.042. Epub 2020 Feb 22.
Necrotic enteritis (NE) is an infection of the gastrointestinal tract and is estimated to cost the global poultry industry billions of dollars annually. A study was conducted to examine whether reducing the crude protein might offset the severity of NE in broilers experimentally challenged with Eimeria spp. on day 9 and Clostridium perfringens on days 14 and 15. Furthermore, increasing the dietary amino acid (AA) density of the diet was also examined owing to identified benefits of improving performance compromised from low protein (LP) diets or NE. A 2 × 2 × 3 factorial arrangement of treatments at 6 replicates per treatment was used with 972 Ross 308 cockerels fed wheat-sorghum-soy-based diets to 35 D. Factors were NE challenge: no or yes; protein: standard (SP) or LP; and AA density: 100% AA, 115% with only essential AA (115% EAA) increased, and 115% AA with both essential and nonessential AA (115% AA) increased. The performance was measured in grower (days 7-21), finisher (days 21-35), and overall (day 7-35) periods. In addition, on day 16, intestinal lesion score and cecal short-chain fatty acids were measured. Only in nonchallenged birds fed LP diets, 115% AA increased grower feed intake (P < 0.01) and body weight gain (P < 0.05) compared to 115% EAA treatments. Challenge increased jejunal lesions (P < 0.001) with no difference between dietary treatments. Finisher body weight gain was greater in nonchallenged birds fed the 115% AA diets than in challenged birds (P < 0.05). Feeding diets with higher nonessential AA encouraged faster recovery from NE challenge. When fed the SP diets, NE challenge increased cecal butyric acid (P < 0.01) and total short-chain fatty acids (P < 0.05). The nutrient matrix used in LP diets does not favor beneficial butyric acid-producing bacteria. Using LP diets to mitigate NE severity does not offset the predisposing effect of E. spp. when attacking the gastrointestinal tract, and NE recovery is favored when feeding SP diets or additional AA.
坏死性肠炎（NE）是一种胃肠道感染，据估计每年给全球家禽业造成数十亿美元的损失。本研究旨在探讨在第 9 天用艾美耳球虫和第 14 天和 15 天用产气荚膜梭菌攻毒的情况下，降低粗蛋白是否可以减轻肉鸡的 NE 严重程度。此外，由于低蛋白（LP）日粮或 NE 引起的性能下降，还研究了提高日粮中氨基酸（AA）密度的效果。在 6 个重复的每个处理中使用 2×2×3 因子处理安排，用含小麦-高粱-大豆的日粮饲养 972 只罗斯 308 公鸡至 35 日龄。因子为 NE 攻毒：有或无；蛋白：标准（SP）或 LP；和 AA 密度：100%AA、仅必需 AA 增加 115%（115%EAA）和必需和非必需 AA 均增加 115%（115%AA）。在生长期（第 7-21 天）、育肥期（第 21-35 天）和总生长期（第 7-35 天）测量性能。此外，在第 16 天测量肠道病变评分和盲肠短链脂肪酸。仅在 LP 日粮饲喂的非攻毒鸡中，115%AA 增加了生长期采食量（P<0.01）和体重增加（P<0.05），而 115%EAA 处理则没有差异。攻毒增加了空肠病变（P<0.001），但日粮处理之间没有差异。在非攻毒鸡中，饲喂 115%AA 日粮的育肥期体重增加大于攻毒鸡（P<0.05）。饲喂高非必需 AA 的日粮促进了 NE 攻毒后的快速恢复。当饲喂 SP 日粮时，NE 攻毒增加了盲肠丁酸（P<0.01）和总短链脂肪酸（P<0.05）。LP 日粮中使用的营养基质不利于产生有益丁酸的细菌。用 LP 日粮减轻 NE 严重程度并不能抵消艾美耳球虫攻毒对胃肠道的易感性，饲喂 SP 日粮或添加 AA 有利于 NE 的恢复。
