Siddique Hafiz Abu Bakar, Khan Ehsaan Ullah, Muneeb Muhammad, Naveed Saima, Soumeh Elham Assadi, Ahmad Sohail, Alhotan Rashed A, Alharthi Abdulrahman S, Abudabos Ala E
Department of Animal Nutrition, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan.
School of Agriculture and Food Sustainability, The University of Queensland, Gatton, QLD 4343, Australia.
Vet Sci. 2025 Jun 27;12(7):622. doi: 10.3390/vetsci12070622.
Decreasing crude protein (CP) in broiler diets can improve sustainability but may compromise growth performance. Feed additives like coated cysteamine hydrochloride (CSH) and exogenous alkaline protease (EAP) can enhance protein utilization and promote gut health. While CSH modulates metabolism, EAP improves digestibility, but their combined effects in low CP diets remain unclear. This study examines the synergistic impact of CSH and EAP on broiler growth, gut histology, carcass traits, immune response, and nutrient digestibility, aiming to optimize performance while reducing environmental impact. Six-hundred, 1-day-old broiler Ross-308 chicks (male) were allotted to four treatments, each consisting of six replicates of twenty-five birds, in a factorial arrangement using a completely randomized design. The treatments comprised two inclusion levels of coated CSH (0.2 and 0.4 g/kg with or without EAP (0 and 0.2 g/kg) in reduced CP diets. A ten percent reduction in CP from the standard requirements of Ross-308 (20.7% vs. 23% in the starter, 19.35% vs. 21.5% in the grower, and 17.55% vs. 19.5% in the finisher phase) was made in all the dietary treatments. A notable interaction ( ≤ 0.05) between CSH and EAP was detected in body weight gain (BWG), feed conversion ratio (FCR), carcass characteristics, and gut morphology during the whole study duration. Similarly, nutrient digestibility and immune response were also influenced by the combined use of CSH and EAP. The synergistic use of coated CSH at 0.2 g/kg or 0.4 g/kg with EAP in reduced CP broiler diets can enhance performance, intestinal health, carcass characteristics, immune response, and nutrient digestibility. Implications of these findings in commercial feeding practices could substantially improve the efficiency and sustainability of broiler production systems.
降低肉鸡日粮中的粗蛋白（CP）含量可提高可持续性，但可能会影响生长性能。诸如包膜盐酸半胱胺（CSH）和外源碱性蛋白酶（EAP）等饲料添加剂可提高蛋白质利用率并促进肠道健康。虽然CSH可调节新陈代谢，EAP可提高消化率，但它们在低蛋白日粮中的联合作用仍不清楚。本研究考察了CSH和EAP对肉鸡生长、肠道组织学、胴体性状、免疫反应和养分消化率的协同影响，旨在在降低环境影响的同时优化生产性能。600只1日龄罗斯308雄性肉鸡被分配到四种处理组，每组采用完全随机设计进行因子排列，包含六个重复，每个重复25只鸡。处理组包括在低蛋白日粮中添加两种水平的包膜CSH（0.2和0.4 g/kg）以及添加或不添加EAP（0和0.2 g/kg）。所有日粮处理均将罗斯308标准需求的CP含量降低10%（育雏期从23%降至20.7%，生长期从21.5%降至19.35%，育肥期从19.5%降至17.55%）。在整个研究期间，CSH和EAP之间在体重增加（BWG）、饲料转化率（FCR）、胴体特征和肠道形态方面存在显著交互作用（≤0.05）。同样，养分消化率和免疫反应也受到CSH和EAP联合使用的影响。在低蛋白肉鸡日粮中协同使用0.2 g/kg或0.4 g/kg的包膜CSH与EAP可提高生产性能、肠道健康、胴体特征、免疫反应和养分消化率。这些研究结果对商业饲养实践的意义可能会大幅提高肉鸡生产系统的效率和可持续性。
