Wang Jinquan, Su Shengchen, Pender Chasity, Murugesan Raj, Syed Basharat, Kim Woo Kyun
Department of Poultry Science, University of Georgia, Athens, GA 30602, USA.
BIOMIN America Inc., Overland Park, KS 66210, USA.
Animals (Basel). 2021 Mar 11;11(3):775. doi: 10.3390/ani11030775.
The aim of this experiment was to evaluate the effect of a phytogenic feed additive (PFA) on growth performance and nutrient digestibility of broilers fed corn and soybean meal-based diets containing two different levels of crude protein. A 2 × 2 completely randomized factorial arrangement (eight replicates/treatment, 30 birds/replicate) was conducted with a positive control (PC) and negative control (NC) containing crude protein at standard or reduced by 1.5% (equivalent to a reduction of 15 g/kg), respectively, and supplementation of PFA at 0 or 125 ppm of diet. There were no significant interactions found between PFA and CP levels in the current study. Main effect analysis showed that during 0-42 d of age NC diets decreased body weight gain ( < 0.05), but increased feed intake ( < 0.05) and feed conversion ratio (FCR, < 0.01), whereas supplementation of PFA resulted in a lower FCR ( < 0.01). The ileal nutrient digestibility was reduced ( < 0.05) in the broilers fed a reduced protein diet at 21 d compared to the standard protein level group, but there were no effects for PFA levels. Similarly, supplementing PFAs showed no effects on digestive enzyme (Alkaline phosphatase, amylase, and lipase) activity in jejunal digesta and jejunal brush border enzyme (maltase, sucrase, and aminopeptidase) activity. Supplementation of PFA downregulated ( < 0.05) the mRNA expressions of cytochrome P450 1A and interleukin 6 in the ileum but had no effects on nutrient transporter genes in the jejunum. In conclusion, supplementation of PFA reduced broiler FCR during the whole grow-out period and positively regulated the immune responses in the ileum.
本实验旨在评估一种植物源饲料添加剂（PFA）对饲喂含两种不同粗蛋白水平的玉米和豆粕型日粮的肉鸡生长性能和养分消化率的影响。采用2×2完全随机析因设计（每个处理8个重复，每个重复30只鸡），设置正对照组（PC）和负对照组（NC），分别含有标准粗蛋白或粗蛋白降低1.5%（相当于减少15 g/kg），日粮中PFA添加量为0或125 ppm。在本研究中，未发现PFA和粗蛋白水平之间存在显著交互作用。主效应分析表明，在0至42日龄期间，NC日粮降低了体重增加（<0.05），但增加了采食量（<0.05）和饲料转化率（FCR，<0.01），而添加PFA导致FCR降低（<0.01）。与标准蛋白水平组相比，21日龄时饲喂低蛋白日粮的肉鸡回肠养分消化率降低（<0.05），但PFA水平对此无影响。同样，添加PFA对空肠食糜中的消化酶（碱性磷酸酶、淀粉酶和脂肪酶）活性以及空肠刷状缘酶（麦芽糖酶、蔗糖酶和氨肽酶）活性均无影响。添加PFA下调了（<0.05）回肠中细胞色素P450 1A和白细胞介素6的mRNA表达，但对空肠中的养分转运基因无影响。总之，添加PFA降低了肉鸡整个育肥期的FCR，并对回肠的免疫反应起到了积极的调节作用。
