Visscher Christian, Mischok Jasmin, Sander Saara, Schmicke Marion, Peitzmeier Eva-Ursula, von dem Busche Isabel, Rohn Karl, Kamphues Josef
Institute for Animal Nutrition, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, D-30173, Hannover, Germany.
Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, D-30173, Hannover, Germany.
BMC Vet Res. 2018 Nov 1;14(1):323. doi: 10.1186/s12917-018-1662-2.
Lawsonia intracellularis is one of the world's most important infectious diseases in pork production with regard to economic losses. So far, studies are missing that describe the effects of a natural infection of piglets on the digestibility of nutrients, possible effects on performance and the morphometrics of the intestine depending on whether piglets are vaccinated, clinically healthy or clinically affected with regard to Lawsonia intracellularis induced diarrhoea.
Digestibility studies were performed on a total of 27 eight-week-old piglets with naturally occurring Lawsonia intracellularis infection in a trial with three repetitions. Nine out of 27 animals were vaccinated as suckling pigs with a commercial Lawsonia intracellularis vaccine (vac; Enterisol®Ileitis). Half of the remaining 18 animals were without clinical signs of infection (non-vac/cs-), half showed moderate clinical signs of Lawsonia intracellularis induced diarrhoea (non-vac/cs+). All three groups were fed one identical complete diet ad libitum. Faecal shedding of Lawsonia intracellularis was found in all groups (25 out of 27 animals). Numerically, the mean excretion in the group non-vac/cs + (7.69 ± 1.65 log copies/ g faeces) was higher in comparison to the group non-vac/cs- (5.83 ± 2.35 log copies/ g faeces) and vaccinated animals (vac: 6.00 ± 2.89log copies/ g faeces). The average daily weight gain (ADG; Ø 8.66 day period) differed significantly (vac: 894 ± 73.3, non-vac/cs-: 857 ± 86.3, non-vac/cs+: 785 ± 137 g/day). The apparent total tract digestibility (ATTD) of nitrogen was significantly lower in clinically affected animals (vac: 83.0 ± 1.72, non-vac/cs-: 83.9 ± 2.03, non-vac/cs+: 80.7 ± 2.57).The total length of the small intestine in clinically affected animals increased significantly (vac: 15.9 ± 1.57, non-vac/cs-: 14.6 ± 1.12, non-vac/cs+: 16.2 ± 1.37 m). The relative body weight depending on the length of the small intestine was lower for clinically affected animals (vac: 1.72 ± 0.21, non-vac/cs-: 1.83 ± 0.17, non-vac/cs+: 1.56 ± 0.12 kg/m).
These studies show that clinically moderate L. intracellularis infections lead to significantly lower ADGs in comparison to vaccinated animals. The disease is also found in altered intestinal morphometry and reduced total N digestibility if clinical signs occur.
就经济损失而言，胞内劳森菌病是全球猪肉生产中最重要的传染病之一。到目前为止，尚缺乏关于仔猪自然感染对营养物质消化率的影响、对生长性能的可能影响以及根据仔猪是否接种疫苗、临床健康或受胞内劳森菌引起的腹泻临床影响而产生的肠道形态学变化的研究。
在一项重复三次的试验中，对总共27头自然感染胞内劳森菌的8周龄仔猪进行了消化率研究。27头仔猪中有9头在哺乳期间接种了市售的胞内劳森菌疫苗（vac；肠立克®回肠炎疫苗）。其余18头仔猪中，一半没有感染的临床症状（未接种疫苗/临床症状阴性），另一半表现出胞内劳森菌引起的腹泻的中度临床症状（未接种疫苗/临床症状阳性）。所有三组仔猪均自由采食相同的全价日粮。所有组中均发现了胞内劳森菌的粪便排出（27头仔猪中有25头）。从数值上看，未接种疫苗/临床症状阳性组（7.69±1.65 log拷贝/g粪便）的平均排出量高于未接种疫苗/临床症状阴性组（5.83±2.35 log拷贝/g粪便）和接种疫苗的动物组（vac：6.00±2.89 log拷贝/g粪便）。平均日增重（ADG；8.66天期间的平均值）差异显著（vac：894±73.3，未接种疫苗/临床症状阴性：857±86.3，未接种疫苗/临床症状阳性：785±137 g/天）。临床受影响动物的氮表观全肠道消化率（ATTD）显著降低（vac：83.0±1.72，未接种疫苗/临床症状阴性：83.9±2.03，未接种疫苗/临床症状阳性：80.7±2.57）。临床受影响动物的小肠总长度显著增加（vac：15.9±1.57，未接种疫苗/临床症状阴性：14.6±1.12，未接种疫苗/临床症状阳性：16.2±1.37 m）。临床受影响动物的相对体重（取决于小肠长度）较低（vac：1.72±0.21，未接种疫苗/临床症状阴性：1.83±0.17，未接种疫苗/临床症状阳性：1.56±0.12 kg/m）。
这些研究表明，与接种疫苗的动物相比，临床中度胞内劳森菌感染导致ADG显著降低。如果出现临床症状，该疾病还会导致肠道形态改变和总氮消化率降低。
