ABSTRACT
In Italy, the use of autogenous inactivated vaccines prepared with the bacterial strains isolated from affected animals is authorized by the Ministry of Health in farms where bacterial diseases occur frequently. The autogenous vaccine performed using Pasteurella multocida is frequently used in rabbit farms, but the feedback of its application is not available. Therefore, the aim of this study is to give information about the impact on the clinical signs of a bivalent autogenous vaccine in rabbits of a genetic centre. The vaccine was prepared using two P. multocida strains belonging to serogroups A and F, equipped with virulence genes and responsible for cyclical outbreak of pasteurellosis in the farm. The vaccine was administered with a first injection, followed by another one after 15 days, then another one four months after the first injection, and then continuing with a further injection every six months to all rabbits. Clinical conditions and mortality rates were monitored for two years after the first vaccination. The improvement in clinical condition and the decrease of the mortality rate were significant especially in the first year post-vaccine. In addition, the number of animals removed due to the disease decreased greatly. Based on the finding of P. multocida strains belonging to serogroup D and serogroup A equipped with different virulence-gene patterns from those previously found, we suggest that the vaccine was unable to prevent the introduction and spreading of new strains among the rabbits.
ABSTRACT
The present work aimed to investigate the effects of nucleotide oral administration on oxidative stress biomarkers, immune responses, gut morphology, serum biochemical parameters, and growth performance in calves from birth to 25 d of life. A total of 40 male Holstein Friesian calves were randomly divided in 2 groups. All the calves were born and reared on the same commercial dairy farm. They were fed the same colostrum, milk replacer, and calf starter. Five grams/head of an additive were orally administered with a syringe directly in the mouth to calves of the nucleotide group (NG). The additive contained 74.12 g/100 g of nucleic acids from hydrolyzed yeast, and 75.38% was free nucleotide sodium salt. The other group represented the negative control (CG). At 25 d of life all of the calves were slaughtered. Calves supplemented with nucleotides had a higher final live weight and improved average daily gain, which was associated with better efficiency of nutrient use. Oral nucleotide administration did not affect IgG absorption efficiency; however, NG calves showed greater duodenum villi length and higher crypt depth compared with CG. Oral nucleotide administration increased the activity of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) and the antioxidant capacity [ferric reducing antioxidant power and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) scavenging activity] both in plasma and in liver. An enhanced ability of cells to counter reactive oxygen species- and reactive nitrogen species-mediated damage was also observed in peripheral blood mononuclear cells from NG. The findings highlight the effectiveness of oral nucleotide administration, and potentially dietary supplementation of nucleotides, in boosting oxidative and immune status in newborn calves.
