Cassiano Eduardo Cuellar Orlandi, Junior Flavio Perna, Barros Tarley Araújo, Marino Carolina Tobias, Pacheco Rodrigo Dias Lauritano, Ferreira Fernanda Altieri, Millen Danilo Domingues, Martins Mauricio Furlan, Pugine Silvana Marina Piccoli, de Melo Mariza Pires, Beauchemin Karen Ann, Meyer Paula Marques, Arrigoni Mario de Beni, Rodrigues Paulo Henrique Mazza
Department of Animal Nutrition and Production, University of São Paulo (FMVZ-USP), Pirassununga, São Paulo 13635-900, Brazil.
Embrapa Beef Cattle, Campo Grande, Mato Grosso do Sul 79106-550, Brazil.
Anim Biosci. 2021 Jan;34(1):74-84. doi: 10.5713/ajas.19.0761. Epub 2020 Apr 12.
Feed additives that modify rumen fermentation can be used to prevent metabolic disturbances such as acidosis and optimize beef cattle production. The study evaluated the effects of liquid and powdered forms of polyclonal antibody preparation (PAP) against Streptococcus bovis and Fusobacterium necrophorum on rumen fermentation parameters in ruminally cannulated non-lactating dairy cows that were adapted or unadapted to a high concentrate diet.
A double 3×3 Latin square design was used with three PAP treatments (control, powdered, and liquid PAP) and two adaptation protocols (adapted, unadapted; applied to the square). Adapted animals were transitioned for 2 weeks from an all-forage to an 80% concentrate diet, while unadapted animals were switched abruptly.
Interactions between sampling time and adaptation were observed; 12 h after feeding, the adapted group had lower ruminal pH and greater total short chain fatty acid concentrations than the unadapted group, while the opposite was observed after 24 h. Acetate:propionate ratio, molar proportion of butyrate and ammonia nitrogen concentration were generally greater in adapted than unadapted cattle up to 36 h after feeding. Adaptation promoted 3.5 times the number of Entodinium protozoa but copy numbers of Streptococcus bovis and Fibrobacter succinogens genes in rumen fluid were not affected. However, neither liquid nor powdered forms of PAP altered rumen acidosis variables in adapted or unadapted animals.
Adaptation of cattle to highly fermentable carbohydrate diets promoted a more stable ruminal environment, but PAP was not effective in this study in which no animal experienced acute or sub-acute rumen acidosis.
可改变瘤胃发酵的饲料添加剂可用于预防酸中毒等代谢紊乱，并优化肉牛生产。本研究评估了抗牛链球菌和坏死梭杆菌的多克隆抗体制剂（PAP）的液体和粉末形式对适应或未适应高浓缩日粮的瘤胃插管非泌乳奶牛瘤胃发酵参数的影响。
采用双3×3拉丁方设计，有三种PAP处理（对照、粉末状和液体PAP）和两种适应方案（适应、未适应；应用于拉丁方）。适应的动物从全草料日粮过渡到80%浓缩日粮，为期2周，而未适应的动物则突然转换日粮。
观察到采样时间与适应之间的相互作用；喂食后12小时，适应组的瘤胃pH值较低，总短链脂肪酸浓度高于未适应组，而24小时后观察到相反的情况。在喂食后长达36小时内，适应的牛的乙酸：丙酸比例、丁酸的摩尔比例和氨氮浓度通常高于未适应的牛。适应使内毛虫原生动物数量增加了3.5倍，但瘤胃液中牛链球菌和琥珀酸纤维杆菌基因的拷贝数未受影响。然而，无论是液体还是粉末形式的PAP均未改变适应或未适应动物的瘤胃酸中毒变量。
牛适应高发酵碳水化合物日粮可促进瘤胃环境更稳定，但在本研究中PAP无效，因为没有动物出现急性或亚急性瘤胃酸中毒。
