The innate immune stimulant Amplimune® is safe to administer to young feedlot cattle.

BACKGROUND: Infectious disease has a significant impact on livestock production. Availability of alternatives to antibiotics to prevent and treat disease is required to reduce reliance on antibiotics while not impacting animal welfare. Innate immune stimulants, such as mycobacterium cell wall fractions (MCWF), are used as alternatives to antibiotics for the treatment and prevention of infectious disease in a number of species including cattle, horses and dogs. This study aimed to evaluate the safety of Amplimune®, an MCWF-based immune stimulant, for weaner Angus cattle. METHODS: On day -1 and 0, sixty mixed-sex Angus weaner cattle were transported for 6 h before being inducted and housed in a large single pen, simulating feedlot induction conditions. The cattle were assigned to one of six treatment groups (n = 10 per group): 2 mL Amplimune intramuscularly (2IM); 2 mL Amplimune subcutaneously (2SC); 5 mL Amplimune intramuscularly (5IM); 5 mL Amplimune subcutaneously (5SC); 5 mL saline intramuscularly (SalIM) and 5 mL saline subcutaneously (SalSC) on day 0 following transportation. Body temperature, body weight, concentrations of circulating pro-inflammatory cytokines (TNFα, IL-1ß, IL-6 and IL-12) and haematology parameters were measured at various times up to 96 h post-treatment. RESULTS: No adverse effects from Amplimune treatment were observed. Amplimune induced an increase in circulating cytokine TNFα concentrations, total white blood cell count and lymphocyte counts indicative of activation of the innate immune system without causing an excessive inflammatory response. CONCLUSIONS: Results confirm that Amplimune can be safely administered to beef cattle at the dose rates and via the routes of administration investigated here.

In vivo imaging in the rabbit as a model for the study of ovulation-inducing factors.

The study of factors responsible for eliciting ovulation in rabbits has been hampered by the lack of a suitable method of monitoring the ovaries in vivo. Ovarian imaging by ultrasound biomicroscopy was used in two experiments designed to determine the effects of seminal plasma on the ovulatory response in rabbits. In Experiment 1, female rabbits were group-housed and treated intramuscularly with saline, gonadotropin releasing hormone (GnRH), or seminal plasma of llamas or rabbits (n = 4 to 6 per group). Rabbits were euthanized eight days later to evaluate the ovarian response by ultrasound biomicroscopy ex situ. No differences among groups were detected in the proportion of rabbits that ovulated or in the number and size of corpora lutea. The high incidence of ovulation in the negative control group was unexpected, and confounded determination of an ovulation-inducing effect of seminal plasma. In Experiment 2, female rabbits were caged individually, and treated as in Experiment 1 (n = 5 to 7 per group). The ovarian response was evaluated in vivo by transcutaneous ultrasound biomicroscopy. Ovulation and formation of corpora lutea were detected only in rabbits given GnRH. A preovulatory surge in plasma luteinizing hormone concentration and a post-ovulatory rise in plasma progesterone concentration were detected only in rabbits treated with GnRH. Surgical translocation of the ovaries to a subcutaneous position enabled longitudinal assessment of the ovulatory response by ultrasound biomicroscopy. Results clearly documented the effect of physical/social interaction on ovulation in rabbits, and did not support the hypothesis that seminal plasma elicits ovulation in rabbits.

Relationship between free radicals produced by entamoeba histolytica and its proteases complex activity.

Entamoeba histolytica is a parasite which causes health problems and there has been many approaches to know what is the factor causing its pathogenicity. In the present work, we assayed if the production of free radicals by the amoeba, has a relationship with the proteases activity. When we test the DMSO action (free radicals quenching activity) the specific activity of the proteases complex of the parasite were affected also. At 33.3% (V/V) concentration of DMSO it was present a maximal decrease of the initial activity (about 46% decrease), for to a higher concentrations existing a trend to recuperate the original activity, suggesting that the free radicals are an important factor for the hydrolysis grade of the protein substrate. All the differences except those between 46.7 and 66.6%, were significantly different compared with the control without any addition. The effects of Probucol and Probucol plus DMSO, compared to those caused by Metronidazol (MZ). We can observe that the quenchers caused a decrease on proteases activity similar to that of MZ (which is an antiparasite drug) and it was of c.a. 58% of activity decrease. These data suggest that the action of both, free radicals and proteases complex of Entamoeba histolytica, can account for the pathogenicity of the parasite.