A comparative study on certain enzymes of the granulocyte from different ruminant species

Occurrence and aetiology of subclinical mastitis in water buffalo in Bangladesh

Subclinical mastitis (SCM) in water buffalo is a production disease associated with decreased milk yield and impaired milk quality and safety. Water buffalo is an important livestock species in Bangladesh, but information about the occurrence and aetiology of SCM in this species is scarce. A cross-sectional study was conducted as part of the Udder Health Bangladesh Programme to (i) determine the occurrence of SCM and bulk milk somatic cell count (SCC) in water buffalo in Bangladesh, (ii) identify pathogens causing SCM and (iii) evaluate penicillin resistance in isolated staphylococci strains. Sixteen buffalo farms in the Bagerhat and Noakhali regions of Bangladesh were selected for study and a bulk milk sample was collected from each farm. In addition, 299 udder quarter milk samples were collected from 76 animals. The bulk milk samples were assessed by direct SCC and the quarter milk samples by California mastitis test (CMT). The occurrence of SCM calculated at quarter and animal level was 42.5 and 81.6%, respectively. Milk samples from 108 CMT-positive quarters in 48 animals and 38 randomly selected CMT-negative quarters in 24 animals were investigated using bacteriological culture. Estimated mean bulk milk SCC was 195 000 cells/ml milk (range 47 000- 587 000 cells/ml milk). On culture, estimated quarter-level intramammary infection (IMI) was 40.4%. The identity of isolated bacteria was confirmed by MALDI-TOF mass spectrometry. Non-aureus staphylococci (NAS) were the most common pathogens (24.7%) and, among 36 NAS tested, 36.1% were resistant to penicillin. Thus there was high occurrence of SCM on the study farms, with relatively high penicillin resistance in NAS. Further studies are needed to identify underlying risk factors and develop an udder health control strategy for water buffalo in Bangladesh.

Aspectos clínicos e laboratoriais da mastite induzida por inoculação intramamária de Staphylococcus aureus em vacas e búfalas

Vários aspectos relacionados à mastite bubalina precisam ser esclarecidos. Muitas condutas são adaptadas a essa espécie pelo conhecimento adquirido com a espécie bovina. Com este experimento, objetivou-se evidenciar particularidades da mastite em búfalas e vacas que tiveram uma glândula inoculada com 1,0 x 103 UFC de S. aureus. Os animais foram monitorados por cultura bacteriana do leite, California Mastitis Test(CMT), e escores para avaliação da severidade da mastite. Foram utilizados os seguintes critérios: temperatura retal, apetite, produção de leite (resposta sistêmica à inflamação), contagem de células somáticas (CCS), aparência/consistência da glândula e aparência da secreção láctea (resposta localizada à inflamação). Todos os animais desenvolveram mastite clínica superaguda. A bactéria foi recuperada de todas as glândulas desafiadas, sem diferença significativa no percentual de isolamento entre as espécies até o 11º dia pós-inoculação, porém com diferença (P<0,001) no 30º dia pós-inoculação. A CCS pelo método eletrônico e o CMT detectaram nas búfalas resposta mais intensa logo após a inoculação e diminuição mais rápida da contagem ao final do experimento, quando se comparou essa espécie com as vacas. Ambos os testes demonstraram correlação com a cultura bacteriana. Na avaliação da severidade da mastite, as médias do escore total, do escore da resposta local e do escore da resposta sistêmica foram mais elevadas na espécie bovina (P<0,05). Ao longo do período de observação, verificou-se uma capacidade superior das búfalas em recuperar o status sanitário adequado, chegando, ao final do experimento, com os parâmetros avaliados mais próximos dos fisiológicos.

The influence of TNFalpha and IL-8 on secretory action of neutrophils isolated from heifers in the course of bovine respiratory disease

The goal of this study was to give insight into the lesser known action of neutrophils in the course of bovine respiratory disease (BRD). Neutrophils are principally involved in resistance to infection but under certain conditions these cells participate in lung injury. TNFalpha and IL-8, primary cytokines which play an essential role in neutrophil activation during the inflammatory process, may lead not only to host defence reaction but also to destructive responses. Neutrophil constituents, such as elastase, myeloperoxidase (MPO), alkaline phosphatase (ALKP) and superoxide among others, contribute to tissue destruction. Also, 5-oxo-eicosatetraenoic acid (5-oxo-ETE), the potent activator of neutrophil chemotaxis and degranulation, can cause lung injury. This study revealed that neutrophils under the influence of TNFalpha exacerbated the release of elastase, MPO, ALKP and superoxide. IL-8, in turn, triggered those neutrophils which were isolated from heifers suffering from BRD, and released elastase, ALKP and 5-oxo-ETE, but not MPO or superoxide (O2(-)). The most pronounced degranulative response was observed in the acute form of BRD and a lesser response was seen in the chronic form. The secretory action of neutrophils varied not only depending on the form and phase of the disease but it also diminished successively during recovery.

Pathways involved in alanyl-glutamine-induced changes in neutrophil amino- and α-keto acid homeostasis or immunocompetence

We examined the effects of DON [glutamine-analogue and inhibitor of glutamine-requiring enzymes], alanyl-glutamine (regarding its role in neutrophil immunonutrition) and alanyl-glutamine combined with L-NAME, SNAP, DON, beta-alanine and DFMO on neutrophil amino and alpha-keto acid concentrations or important neutrophil immune functions in order to establish whether an inhibitor of *NO-synthase [L-NAME], an *NO donor [SNAP], an analogue of taurine and a taurine transport antagonist [beta-alanine], an inhibitor of ornithine-decarboxylase [DFMO] as well as DON could influence any of the alanyl-glutamine-induced effects. In summary, irrespective of which pharmacological, metabolism-inhibiting or receptor-mediated mechanisms were involved, our results showed that impairment of granulocytic glutamine uptake, modulation of intracellular glutamine metabolisation and/or de novo synthesis as well as a blockade of important glutamine-dependent metabolic processes may led to significant modifications of physiological and immunological functions of the affected cells.

Relationships Between Somatic Cell Count and Intramammary Infection in Buffaloes

The objectives of this study were to evaluate the presence of intramammary infections (IMI) in dairy buffaloes and to examine the relationships among IMI, somatic cell counts (SCC), and milk production traits. Two farms in northern Italy were visited monthly for a complete milking season. Quarter-based milk samples were collected at each visit from 46 buffaloes. A total of 1,912 samples were assessed in this experiment. Samples were cultured for bacterial presence and were tested for SCC and percentages of milk protein and fat. In addition, daily milk yield was recorded from each buffalo. Prevalence of IMI was large; 63% of quarters were infected. No buffalo remained free from IMI throughout the course of the study. Coagulase-negative staphylococci were the most common pathogen (66% of positive samples). The SCC was distinctly greater in infected quarters; 100% of quarters with SCC >200,000 cell/mL had IMI, whereas 98% of quarters with SCC below this threshold were uninfected. The somatic cell scores (SCS) in these buffaloes were much lower than those commonly observed in dairy cattle. The mean SCS from quarters with IMI was only 2.93. The highest SCS was observed in quarters infected by streptococci. No drastic decrease in milk yield was observed among infected buffaloes relative to healthy contemporaries. The relatively low SCS and lack of a strong effect on milk yield provide evidence to discourage antibiotic treatment of buffaloes for subclinical IMI during lactation.

An evaluation of the metabolic basis of aflatoxin B1 toxicity by using buffalo granulocytes and agranulocytes in vitro

This study was aimed at monitoring cytotoxic changes in buffalo leukocyte subpopulations exposed to aflatoxin B1 (AFB1), since no such information is available for this species. The effects of AFB1 on glutathione (GSH) S-transferase, Ca2+Mg2+ATPase and protein synthesis in leukocyte subpopulations, namely, mononuclear (MN) cells and polymorphonuclear (PMN) cells isolated from the blood of the domestic buffalo (Bos bubalis), were studied. The cells were separated by using Ficoll-Paque and incubated in the presence of AFB1. GSH S-transferase activity was found to increase in cells exposed to AFB1, but there was no difference in activity between MN and PMN cells. PMN cell ATPase activity increased after AFB1 treatment, whereas no such effect was observed in the MN cells, which showed higher basal levels of ATPase activity. In the presence of AFB1, all the cells showed significant decreases in 14C-leucine incorporation, but the MN cells showed higher 14C-leucine incorporation than the PMN cells. Nevertheless, both cell types were affected by AFB1 and participated in its detoxification. There was also an appreciable decrease in the release of myeloperoxidase by activated PMN cells in the presence of AFB1.

Host defense function in neutrophils from the American bison (Bison bison)

Selected host defense functions of neutrophils isolated from American bison (Bison bison) were characterized and compared with those of cattle (Bos taurus). Bison neutrophils had a robust chemotactic response to both IL-8 and LTB(4), with maximal responses occurring at 10(-7) M (IL-8) and 10(-8) M (LTB(4)). The magnitude of the chemotactic response to IL-8 was similar in bison and bovine neutrophils (except at 10(-7) M IL-8, where bison had a stronger response). In response to LTB(4), bison neutrophils had a much stronger chemotaxis at both 10(-8) and 10(-7) M than did bovine cells. Production of reactive oxygen species (ROS) in response to phorbol myristate acetate (PMA) and opsonized zymosan (OpZ) was similar between bison and bovine neutrophils. However, the production of ROS in bison neutrophils stimulated with OpZ was primarily intracellular, while extracellular release of ROS was evident in bovine neutrophils stimulated with OpZ. Like bovine neutrophils, bison neutrophils did not generate a respiratory burst in response to fMLF. Granules prepared from bison neutrophils had potent direct killing action on the Gram-negative bacteria Escherichia coli but failed to kill the Gram-positive bacteria Staphylococcus aureus and, at intermediate doses, actually had a permissive effect for this bacteria. Thus, bison neutrophils have potent host defense capabilities similar in quality to those of bovine neutrophils; however, unique differences are present, which may allow bison neutrophils to respond to the distinct immunological challenges that bison encounter.