Efficacy of a community-based dietary intervention to enhance micronutrient adequacy of high-phytate maize-based diets of rural Malawian children

OBJECTIVE: To evaluate the efficacy of a community-based dietary intervention to reduce risk of micronutrient inadequacies in high-phytate maize-based Malawian diets. DESIGN: Quasi-experimental post-test design with a non-equivalent control group. SETTING: Four villages in Mangochi District, Southern Malawi. PARTICIPANTS: Households with children aged 3-7 years in two intervention (n = 200) and two control (n = 81) villages participated in a 6-month intervention employing dietary diversification, changes in food selection patterns, and modifications to food processing to reduce the phytate content of maize-based diets. Baseline comparability between the groups was confirmed via assessment of sociodemographic characteristics, anthropometry, knowledge and practices, morbidity, haemoglobin and hair zinc. After 12 months, knowledge and practices and dietary intakes were assessed by interactive 24-hour recalls, one during the food plenty and a second during the food shortage season. Nutrient adequacy for the two groups was compared via dietary quality indicators and predicted prevalence of inadequate intakes using the probability approach. RESULTS: Intervention children had diets that were significantly more diverse and of a higher quality than those of controls. Median daily intakes of protein, calcium, zinc (total and available), haem iron, vitamin B12 and animal foods (grams; % of total energy) were higher (P < 0.05) whereas phytate intakes, phytate/zinc and phytate/iron molar ratios were lower (P < 0.01) in the intervention group; some spread of knowledge and practices to controls occurred. CONCLUSIONS: Our community-based dietary strategies reduced the predicted prevalence of inadequate intakes of protein, calcium, zinc and vitamin B12, but not iron, in children from Malawian households with very limited resources.     

CXCL8 attenuates chemoattractant-induced equine neutrophil migration

The chemokine, CXCL8, is a potent chemoattractant but it has also been shown to attenuate the migratory response of human neutrophils to the bacterial peptide, FMLP; this could lead to retention of cells in infected tissue and, potentially, to enhanced clearance of bacteria. This study has examined the effect of CXCL8 on equine neutrophil migration and adherence in response to PAF and LTB(4), chemoattractants that may play a role in non-infectious inflammatory conditions of the horse associated with neutrophil recruitment to the target tissue. The effects of CXCL8 on PAF- and LTB(4)-induced responses were determined using a ChemoTx plate migration assay and by measuring adhesion to protein-coated plastic. The CXCR1/2 antagonist, SB225002, was used to investigate whether the observed effects were receptor mediated and the role of cAMP was examined by measuring intracellular cAMP following exposure to agonists alone and in combination and by establishing the effect of dibutyryl cAMP on neutrophil migration. CXCL8, LTB(4) and PAF each induced migration and adhesion. Exposure of neutrophils to a combination of CXCL8 and PAF reduced the magnitude of the responses to that of unstimulated cells. In contrast, although the effect was less than additive, the response to co-stimulation with CXCL8 and LTB(4) were not nearly as pronounced. CXCL8 acted in a receptor mediated manner, the attenuation of PAF-induced responses being reversed by SB225002 at a concentration that blocks CXCR2. CXCL8, PAF and LTB(4) alone increased intracellular cAMP. In co-incubation studies, combination of CXCL8 with PAF led to an additive increase in cAMP whereas no increase above that obtained in response to LTB(4) alone was seen. Dibutyryl cAMP significantly reduced neutrophil migration in response to either CXCL8 or PAF alone. These results demonstrate that CXCL8, in addition to being a potent chemoattractant and pro-adhesive molecule for equine neutrophils, is able to attenuate responses to PAF and, to a much lesser extent, LTB(4). This effect, which appears to be CXCR2-mediated and cAMP dependent, could lead in vivo to trapping of cells at sites of inflammation resulting potentially in either enhanced clearance of injurious stimuli or increased local tissue damage by activated cells.     

Interaction of rotavirus and enterotoxigenic Escherichia coli in conventionally-reared dairy calves

A study was made of the effects of rotavirus and/or enterotoxigenic Escherichia coli (ETEC) on dairy calves born and suckled on the farm and subsequently reared in isolation. Calves were orally inoculated at 6 days old with either rotavirus (5), ETEC (7), rotavirus and ETEC (5) or remained uninoculated controls (4), and their reactions were recorded by clinical, microbiological, and pathological observations. Rotavirus infection consistently produced diarrhoea, while ETEC inoculated alone did not colonise the intestine. In dual infections, both rotavirus and ETEC multiplied, although the severity of diarrhoea was not greater than that caused by rotavirus alone. Some ETEC-inoculated calves developed subsequent naturally-acquired rotavirus infections, but in these no ETEC multiplication occurred. The results suggest that prior or simultaneous rotavirus infection is necessary to enable ETEC colonisation of the intestine in convenstional calves of this age.     

Characterisation of the pig acute phase protein response to road transport

The acute phase protein (APP) response was evaluated after prolonged transportation of pigs under commercial conditions. Elevated serum APP concentrations were observed in two groups of boars immediately after their arrival at a destination farm compared with within-animal control samples obtained one month later. The effect was more pronounced in the first group of pigs conveyed under average transport conditions (Transport 1, 24 h), although the second group was transported for a longer time period (Transport 2, 48 h) but in superior transport conditions. In a second trial, pigs were sampled before transport, on arrival at an abattoir (following 12 h transport), and at the slaughter-line (after 6 h lairage). Significant increases in major acute phase protein (Pig-MAP), haptoglobin, serum amyloid A, C-reactive protein, and a decrease in apolipoprotein A-I, were observed at slaughter. The results demonstrate that shipment of pigs by road can result in an APP response that is probably related to the stress of transport.     

Decision making on helminths in cattle: diagnostics,economics and human behaviour

Helminth infections of cattle affect productivity in all classes of stock, and are amongst the most important production-limiting diseases of grazing ruminants. Over the last decade, there has been a shift in focus in the diagnosis of these infections from merely detecting presence/absence of infection towards detecting its impact on production. This has been facilitated by studies observing consistent negative correlations between helminth diagnostic test results and measures of productivity. Veterinarians are increasingly challenged to consider the economic aspects of their work, and the use of these tests should now be integrated in economic evaluation frameworks for improved decision making. In this paper, we review recent insights in the farm-specific economic impact of helminth infections on dairy cattle farms as well as in farmer attitudes and behaviour regarding helminth control. Combining better economic impact assessments of helminth infections together with a deeper understanding of the non-economic factors that drive a farmer’s animal health decisions should result in more effective control strategies and increased farmer satisfaction.