Diego Grilli

Isolation of Pseudobutyrivibrio ruminis and Pseudobutyrivibrio xylanivorans from rumen of Creole goats fed native forage diet

We isolated and identified functional groups of bacteria in the rumen of Creole goats involved in ruminal fermentation of native forage shrubs. The functional bacterial groups were evaluated by comparing the total viable, total anaerobic, cellulolytic, hemicellulolytic, and amylolytic bacterial counts in the samples taken from fistulated goats fed native forage diet (Atriplex lampa and Prosopis flexuosa). Alfalfa hay and corn were used as control diet. The roll tubes method increased the possibility of isolating and 16S rDNA gene sequencing allowed definitive identification of bacterial species involved in the ruminal fermentation. The starch and fiber contents of the diets influenced the number of total anaerobic bacteria and fibrolytic and amylolytic functional groups. Pseudobutyrivibrio ruminis and Pseudobutyrivibrio xylanivorans were the main species isolated and identified. The identification of bacterial strains involved in the rumen fermentation helps to explain the ability of these animals to digest fiber plant cell wall contained in native forage species.

Brucella alters endocytic pathway in J774 macrophages

Brucella is a facultative intracellular bacterium which causes chronic infections in mammals by surviving and replicating within host cells. The putative role of the endoplasmic reticulum (ER) in the formation of the phagosome in non-professional phagocytes is supported by several research groups, but still leaves open the question of the fate of Brucella inside professional phagocytes and its resistance mechanisms therein. Macrophages are particularly important for the survival and spreading of Brucella during infection. The intracellular transport of Brucella in these cells has not been thoroughly characterized. To study the maturation process of Brucella-containing phagosomes in phagocytes, we comparatively monitored the intracellular transport of a virulent strain (2308) with two vaccine strains (S19 and RB51) in J 774 macrophages. Then, we compared the behavior of all three strains studied through transmission electron microscopy. The results indicate that the virulent strain not only occupies two different kinds of compartments but also alters the endocytic pathway of the cell it parasitizes, unlike what has been reported for non-professional phagocytes, like HeLa cell. Besides, differences are observed in the behavior of both Brucella abortus vaccine strains.

Analysis of the rumen bacterial diversity of goats during shift from forage to concentrate diet.

High-grain feeding used in the animal production is known to affect the host rumen bacterial community, but our understanding of consequent changes in goats is limited. This study was therefore aimed to evaluate bacterial population dynamics during 20 days adaptation of 4 ruminally cannulated goats to the high-grain diet (grain: hay - ratio of 40:60). The dietary transition of goats from the forage to the high-grain-diet resulted in the significant decrease of rumen fluid pH, which was however still higher than value established for acute or subacute ruminal acidosis was not diagnosed in studied animals. DGGE analysis demonstrated distinct ruminal microbial populations in hay-fed and grain-fed animals, but the substantial animal-to-animal variation were detected. Quantitative PCR showed for grain-fed animals significantly higher number of bacteria belonging to Clostridium leptum group at 10 days after the incorporation of corn into the diet and significantly lower concentration of bacteria belonging to Actinobacteria phylum at the day 20 after dietary change. Taxonomic distribution analysed by NGS at day 20 revealed the similar prevalence of the phyla Firmicutes and Bacteroidetes in all goats, significantly higher presence of the unclassified genus of groups of Bacteroidales and Ruminococcaceae in grain-fed animals and significantly higher presence the genus Prevotella and Butyrivibrio in the forage-fed animals. The three different culture-independent methods used in this study show that high proportion of concentrate in goat diet does not induce any serious disturbance of their rumen ecosystem and indicate the good adaptive response of caprine ruminal bacteria to incorporation of corn into the diet.

Effect of the Rearing System on the Establishment of Different Functional Groups of Microorganism in the Rumen of Kid Goats / Uticaj Sistema Uzgoja Na Uspostavljanje Različitih Funkcionalnih Grupa Mikroorganizama U Buragu Jaradi

Abstract This study was aimed to determine the effect of the rearing system on the establishment and development of different functional groups of microorganisms in the rumen of kid goats. Fifty kids were fed on goat milk until weaning at 45 (TR, traditional rearing system, n = 25) and 30 days of age (alternative rearing system, AR, n = 25). In addition, only AR group was offered with rumen starter from birth. Both groups consumed alfalfa hay and ground corn between 30 and 90 days of age. Five kids from each group were slaughtered at 21, 30, 45, 70 and 90 days old. It was determined the total number of protozoa, anaerobic, amylolytic and cellulolytic bacteria present in the rumen. Kids of AR were lighter in weight than TR kids between 42 and 56 days old. In both rearing systems, anaerobic and amylolytic bacteria were found at 21 days of age, while cellulolytic and protozoa were not found until 45 days of age. Kids of AR had higher quantities of anaerobic and amylolytic bacteria until 30 and 45 days of age, respectively. These results demonstrate the rearing system does not affect the sequence and time in which the functional groups of microorganisms are established in the rumen. However, the alternative rearing system with early intake of solid food allowed the establishment of greater amount of bacteria and protozoa. Nevertheless, the effect of weaning on growth rate was more marked in kids from alternative rearing system, despite its greater microbiological rumen development. Ova studija je imala za cilj da utvrdi uticaj sistema uzgoja na uspostavljanje i razvoj različitih funkcionalnih grupa mikroorganizama u buragu jaradi. Pedeset jaradi je hranjeno kozjim mlekom do odbijanja 45-og dana (TR, tradicionalni sistem uzgoja, n= 25) i 30-og dana starosti (alternativni sistem uzgoja, AR n=25). Jarad iz AR grupe je dobijala rumen starter od rođenja.Obe grupe su konzumirale seno lucerke i mleveni kukuruz od 30-og do 90-tog dana starosti. Iz svake grupe je žrtvovano po 5 jaradi 21, 30, 70 i 90-tog dana starosti. Određivan je ukupan broj protozoa, anaerobnih, amilolitičkih i celulolitičkih bakterija prisutnih u buragu. Jarad iz AR grupe imali su manju telesnu težinu u odnosu na jarad iz TR grupe u periodu između 42. i 56. dana starosti. Kod jaradi iz oba sistema uzgoja 21. dana starosti su ustanovljene anaerobne i amilolitičke bakterije, dok celulolitičke bakterije i protozoe nisu ustanovljene sve do 45-tog dana starosti. Jarad iz AR grupe su imala veće količine anaerobnih i amilolitičkih bakterija do 30., odnosno 45. dana starosti. Ovi rezultati pokazuju da sistem uzgoja ne utiče na vreme i redosled uspostavljanja funkcionalnih grupa mikroorganizama u buragu. Međutim, alternativni sistem uzgoja, koji podrazumeva rani unos čvrste hrane, omogućava uspostavljanje većeg broja bakterija i protozoa. Ipak, efekat zalučenja na rast je bio izraženiji kod jaradi u alternativnom sistemu odgoja, uprkos značajnijem mikrobiološkom razvoju buraga.

Frecuencia de dermatofitos en una muestra de felinos del área urbana del Gran Mendoza, Argentina

BACKGROUND The cat, considered the main reservoir of Microsporum canis, lives in urban areas, and also plays an important role in the emergence of dermatomycoses. AIMS To determine and analyse the frequency of zoonotic dermatophytes in a sample of cats in an urban area of the Gran Mendoza region. METHODS The animals selected were household cats and cats less than one year old that came from shelters and kennels from urban areas in the Gran Mendoza region. A total of 45 samples from cats with and without dermatological lesions were analysed. These samples were collected through skin scraping, hair removal and Mackenzie brush, respectively. Direct observation was made with KOH and glycerol after heat exposure. Samples were cultured on Sabouraud and Lactrimel agar slants with chloramphenicol and cycloheximide for 30 days. RESULTS The frequency of dermatophytes isolated in this preliminary study was 13.3%. There were not statistically significant differences by source, age, sex, race or dermatological condition. Zoonotic dermatophytes were found in 2 household cats out of the 21 that had direct contact with children or the elderly. M. canis was isolated in 83.3% cases. CONCLUSIONS The frequency of isolation of zoonotic dermatophytes in the sample of cats in an urban area of the Gran Mendoza region was 13.3%, a value higher than expected. M. canis was the most isolated species.