Kiarie Elijah G, Leung Haley, Akbari Moghaddam Kakhki Reza, Patterson Rob, Barta John R
Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada.
Department of Technical Services and Innovation, Canadian Bio-Systems Inc., Calgary, AL, Canada.
Front Vet Sci. 2019 Dec 20;6:473. doi: 10.3389/fvets.2019.00473. eCollection 2019.
Coccidiosis induced necrotic lesions impair digestive capacity and barrier function in concurrence with increased risks for secondary bacterial infections. The industry has been successful in controlling coccidiosis with anticoccidials and vaccination. However, concerns over species resistant to anticoccidials, gaps in vaccination and restriction on antibiotics is stimulating research and application of alternative and/or complimentary strategies for coccidiosis control. The aim of this paper is to appraise literature on the utility of feed enzymes and yeast derivatives in modulating coccidiosis. Feed enzymes can complement endogenous enzymes (protease, amylase, and lipase) that may become insufficient in coccidiosis afflicted birds. Coccidiosis in the upper small intestine creates conditions that enhances efficacy of phytase and there are reports indicating supplemental phytase can mitigate the negative impact of coccidiosis on bone quality. Increase in intestinal short chain fatty acids due supplemental fiber degrading enzymes has been linked with reduced survivability of . There is evidence whole yeast (live or dead) and derivatives can modulate coccidiosis. Immunomudulation properties of the yeast derivatives have been shown to enhance cellular and humoral immunity in challenge models which is critical for effectiveness of coccidial vaccination. Moreover, yeast nucleotides have been shown to be beneficial in stimulating healing of intestinal mucosal surface. Other novel work has shown that certain yeast cells can produce derivatives with anticoccidial compounds effective in attenuating oocysts shedding. Yeast cell surface has also been shown to be an effective oral vaccine delivery vehicle. Overall, while further refinement research is warranted to address inconsistencies in responses and commercial application, there is evidence feed enzymes and yeast derivatives could complement strategies for maintaining intestinal function to bolster growth performance in broilers compromised with coccidiosis. However, broilers receive diets containing several feed additives with distinct mode of actions and yet there is dearth of empirical data on the expected responses.Future evaluations should consider combinations of additives to document animal responses and potential synergies.
球虫病引发的坏死性病变会损害消化能力和屏障功能，同时增加继发细菌感染的风险。该行业已成功地通过抗球虫药和疫苗接种来控制球虫病。然而，对抗球虫药耐药的物种、疫苗接种的差距以及抗生素的限制等问题，正促使人们研究和应用控制球虫病的替代和/或补充策略。本文旨在评估关于饲料酶和酵母衍生物在调节球虫病方面效用的文献。饲料酶可以补充内源性酶（蛋白酶、淀粉酶和脂肪酶），这些酶在感染球虫病的禽类中可能会不足。小肠上段的球虫病会创造条件提高植酸酶的功效，并且有报告表明补充植酸酶可以减轻球虫病对骨骼质量的负面影响。补充纤维降解酶导致肠道短链脂肪酸增加，这与[未提及的病原体]的生存能力降低有关。有证据表明全酵母（活的或死的）及其衍生物可以调节球虫病。酵母衍生物的免疫调节特性已被证明能在攻毒模型中增强细胞免疫和体液免疫，这对于球虫疫苗接种的有效性至关重要。此外，酵母核苷酸已被证明有助于刺激肠道黏膜表面的愈合。其他新的研究表明，某些酵母细胞可以产生具有抗球虫化合物的衍生物，这些化合物能有效减少卵囊排出量。酵母细胞表面也已被证明是一种有效的口服疫苗递送载体。总体而言，虽然需要进一步完善研究以解决反应和商业应用中的不一致问题，但有证据表明饲料酶和酵母衍生物可以补充维持肠道功能的策略，以提高感染球虫病的肉鸡的生长性能。然而，肉鸡所食用的日粮中含有几种作用方式不同的饲料添加剂，但关于预期反应的实证数据却很匮乏。未来的评估应考虑添加剂的组合，以记录动物的反应和潜在的协同作用。
