Collins Alison, Bowring Bethany
New South Wales Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW 2568, Australia.
Centre for Infectious Diseases and Microbiology, the Westmead Institute for Medical Research, Sydney, NSW 2145, Australia.
Animals (Basel). 2023 Oct 16;13(20):3229. doi: 10.3390/ani13203229.
Pigs are especially vulnerable to intestinal pathogens and dysbiosis in the first two weeks after weaning. Infection with enterotoxigenic strains of (ETEC) in combination with poor nutrition and hygiene can lead to diarrhea, poor growth and increased mortality. While neomycin and zinc oxide can prevent post-weaning diarrhea (PWD), their broad-spectrum activity also kills commensal microbiota and can lead to the emergence of heavy metal and antimicrobial resistance. Bromelain prevents attachment of F4 ETEC to intestinal enterocytes by cleaving the host receptor. In controlled environmental facilities, weaned pigs treated with either therapeutic levels of neomycin sulfate, zinc oxide, bromelain or non-treated were monitored for diarrhea, weight gain, feed intake, feed efficiency, excretion of F4 ETEC, changes to their intestinal microbiomes and antimicrobial resistance in . The treatment effects were evaluated at weaning, during two weeks of treatment and for three weeks after treatments ceased. Minimal clinical signs of PWD were observed, except in zinc-treated pigs post treatment. Intestinal dysbiosis was observed in response to diarrhea and in pigs treated with both neomycin and zinc. Antimicrobial resistance increased in commensal isolated from neomycin- and zinc-treated pigs. In contrast, bromelain controlled PWD and prevented intestinal dysbiosis without inducing antimicrobial resistance.
仔猪在断奶后的头两周特别容易受到肠道病原体和肠道菌群失调的影响。感染产肠毒素大肠杆菌（ETEC）菌株，再加上营养不良和卫生条件差，会导致腹泻、生长缓慢和死亡率增加。虽然新霉素和氧化锌可以预防断奶后腹泻（PWD），但其广谱活性也会杀死共生微生物群，并可能导致重金属和抗菌药物耐药性的出现。菠萝蛋白酶通过切割宿主受体来阻止F4 ETEC附着于肠道肠上皮细胞。在可控环境设施中，对用治疗剂量的硫酸新霉素、氧化锌、菠萝蛋白酶处理或未处理的断奶仔猪进行腹泻、体重增加、采食量、饲料效率、F4 ETEC排泄、肠道微生物群变化以及抗菌药物耐药性监测。在断奶时、治疗两周期间以及停止治疗后三周评估治疗效果。除了锌处理的仔猪在治疗后出现症状外，观察到PWD的临床症状很轻微。观察到腹泻以及新霉素和锌处理的仔猪出现肠道菌群失调。从新霉素和锌处理的仔猪中分离出的共生菌的抗菌药物耐药性增加。相比之下，菠萝蛋白酶可控制PWD并预防肠道菌群失调，且不会诱导抗菌药物耐药性。
