Use of a graft of demineralized bone matrix along with TGF-β1 leads to an early bone repair in dogs

Tibia fractures are common in small animal practice. Over the past decade, improvements to animal internal fracture fixation have been developed. TGF-β1 has been shown to be crucial in the development, induction and repair of bone. In present study, we investigate the effect of local application of a graft demineralized bone matrix (DBM) along with TGF-β1 in a model of open osteotomy induced experimentally in dogs. Tibia fracture was brought about by using an open osteotomy model in young male dogs. Fracture repair was evaluated by a histological and biochemical analysis. Collagen content, proteolytic activity and urokinase-type plasminogen activator (uPA) expression were analyzed at the end of the study. Radiographic analysis, alkaline phosphatase and hematological evaluation were performed weekly. At the fifth week, there was an improvement and restoration of bone architecture in animals treated with a graft containing TGF-β1 (5 ng/ml) compared with the control and graft groups, as was evidenced by the presence of an early formation of wide callus and bone regeneration. In addition, local application of TGF-β1 led to an increase in collagen and proteolytic activity. More immunopositive osteoclast and mesenchymal cells were found in bone tissue from animals treated with TGF-β1 as compared with the control group. No changes in alkaline phosphatase, hematological and clinical parameters were observed. This study shows that the combined use of DBM along with TGF-β1 is able to improve and accelerate the bone repair.     

In vitro inhibition of Citrobacter freundii, a red-leg syndrome associated pathogen in raniculture, by indigenous Lactococcus lactis CRL 1584

Red-leg syndrome (RLS) is one of the main infectious diseases that cause economic losses in Lithobates catesbeianus hatcheries, Citrobacter freundii being an etiological agent. Treatment or prevention with therapeutics or chemicals results in modifications of the indigenous microbiota, development of antibiotic resistance, presence of their residues in food and enhancement of production costs. Thus, probiotics could be used as an alternative therapy. Lactic acid bacteria are part of the indigenous microbiota of healthy frogs and can prevent pathogen colonization by different mechanisms, including the production of antagonistic substances. In this work, the evaluation and characterization of the inhibition of C. freundii CFb by Lactococcus lactis subsp. lactis CRL 1584, a potentially probiotic candidate, were carried out. This strain produced lactic acid, H(2)O(2) and bacteriocin in static and shaken conditions and inhibited pathogen growth in associative cultures, with an earlier inhibition under agitated conditions. The elimination of each of the antimicrobial metabolites partially abolished the inhibition of the pathogen, suggesting that the inhibitory effect could be attributed to a combined action of the three antagonistic molecules. Electron microphotographs revealed the damage caused by L. lactis CRL 1584 supernatants to C. freundii cells. The addition of pure lactic acid, H(2)O(2) and bacteriocin to the culture media showed that each metabolite caused different morphological modifications in C. freundii, in agreement with the effect on viable cell counts. The results support the possibility that L. lactis CRL 1584 might be considered as a probiotic to be used in the prevention of RLS in raniculture.     

Evaluation of transformation growth factor beta1, interleukin-10, and interferon-gamma in male symptomatic and asymptomatic dogs naturally infected by Leishmania (Leishmania) chagasi

The aims of this study were to evaluate the immunomodulatory role of TGF-β₁, IL-10, and INF-γ in spleen and liver extracts and supernatant cultures of white spleen cells from male symptomatic and asymptomatic dogs, naturally infected by Leishmania (Leishmania) chagasi. Thirty dogs from Araçatuba, São Paulo, Brazil, an endemic leishmaniosis area, were selected by positive ELISA serological reaction for Leishmania sp. and divided into two groups: asymptomatic (n = 15) and symptomatic (n = 15) consisting of animals with at least three characteristic signs (fever, dermatitis, lymphoadenopathy, onychogryphosis, weight loss, cachexia, locomotion problems, conjunctivitis, epistaxis, hepatosplenomegaly, edema, and apathy). After euthanasia, spleen and liver fragments were collected for ex vivo quantification of TGF-β₁, IL-10, and INF-γ. Naturally active in vitro produced TGF-β₁ was also evaluated in spleen cell culture supernatant. Spleen and liver extract of asymptomatic dogs had higher mean TGF-β₁ levels than symptomatic dogs. High concentrations of IL-10 were found in spleen, and mainly in liver extract of both groups. Higher INF-γ concentrations were found in spleen extracts of symptomatic dogs, and in liver extracts of asymptomatic dogs. Extract of this cytokine was lower in spleen extract. Although INF-γ is being produced in canine infection, mean levels of TGF-β₁ and IL-10 from spleen and liver extracts were quantitatively much higher; suggesting that immune response in both asymptomatic and symptomatic dogs was predominantly type Th2.     

Vitamin and trace mineral content in feed of breeders and their progeny: effects of growth, feed conversion and severity of malabsorption syndrome of broilers

1. A study was conducted to investigate the effects of several vitamins and trace elements chickens and in chickens experimentally infected with malabsorption syndrome (MAS). 2. Vitamins and trace minerals in feed were varied. Breeders received either a basal amount of vitamins and trace minerals (low mix) or an increased amount (high mix). Their progeny also received either a low mix or a high mix. Effects of different breeder and broiler mix combinations on broiler performance, heamatology, spleen weight and humoral response were examined in control chickens. The effects of the different feeds and breeder, broiler combinations at the severity and recovery of MAS infection were also studied. 3. In general, the immune system can be stimulated by addition of vitamins and trace minerals, without affecting the growth potential of the controls. The number of leukocytes increased on d 1 in the broilers descended from breeders receiving high mix. The response to Newcastle disease virus boost was affected by the different amount of vitamins. 4. When breeders received a high mix the number of infiltrating polymorphonuclear leukocytes in the intestine was higher compared with breeders receiving basal amounts of minerals and vitamins. Also the recovery rate of intestinal lesions, cystic crypts of Lieberkühn and villus atrophy, as observed by histopathology, was faster in the groups where the breeders received high mix.     

In vitro susceptibility of field isolates of Francisella tularensis subsp. holarctica recovered in Spain to several antimicrobial agents

Forty-two recent (1997-1999) Spanish isolates of Francisella tularensis subsp.holarctica were tested in a broth microdilution method for their susceptibilities to 29 antimicrobial agents, including penicillins, cephalosporins, cephamicins, monobactams, penems, aminoglycosides, tetracyclines, macrolides, quinolones, chloramphenicol and fosfomycin. The isolates were resistant to beta-lactam antibiotics and susceptible to chloramphenicol, ciprofloxacin, levofloxacin and norfloxacin.     

Milk utilisation patterns in the low-input production systems in South Africa

Understanding the utilisation patterns of milk assists in designing appropriate dairy development schemes in rural communities. The objective of the study was to determine milk utilisation patterns in different smallholder farming systems in the Eastern Cape Province of South Africa. Data were collected through the administration of recording sheets to 130 randomly selected households in Alice, Fort Beaufort and Queenstown districts. Amounts of milk produced per household ranged from 9 to 21 l per household per day. Milk consumption/household/day was similar among the three districts. Milk consumption in the early lactation doubled the amount consumed in late lactation (P < 0.05). Milk in the communal areas was largely utilised as fresh or sour milk. Fresh milk was mostly used in tea/coffee or to make porridge for children. Sour milk was consumed with thick boiled maize meal. Fort Beaufort (10.2 ± 1.37 l/day) had the highest sour milk sales whilst Queenstown had the highest fresh milk sales (9.7 ± 5.57 l/day). It was concluded that quantities of milk consumed or sold as fresh or sour were generally low and varied across smallholder farming systems.