clients that all areas of the farm are covered by this whether or not they are visible to the public. We are encouraging clients to review the appearance of their farm and identify areas that need tidying and then act on this, e.g. by disposing of old machinery. A Livestock Health Plan, written and updated in conjunction
with the vet is a cornerstone of assurance schemes. Most, if not all assurance schemes require the implementation of the National Johne’s Management Plan to manage Johne’s disease. Although it has long been best-practice, from 1/10/19 Red Tractor assurance includes “Colostrum or milk from known Johne’s positive cows must not be fed to dairy or beef breeding stock”. In some cases, milk buyer requirements supersede farm assurance standards – at least one milk buyer now
Scientifically Speaking …
By Matthew Wedzerai
ZnO nanoparticles in piglet diets – environmentally friendly! Zinc oxide improves growth performance and inhibits intestinal inflammation in weaned piglets. However, due to its low digestibility, high doses of ZnO greatly increase zinc excretion and cause environmental pollution. In recent times nanotechnology has been developing fast and provides a new dimension for the exploration of substitutes for dietary conventional concentrations of ZnO in weaned piglets. Owing to the decreased particle size, increased surface area, high chemical stability, and enhanced reactivity, ZnO nanoparticles have great potential.
Early weaning remains a critical phase in pig production, and is associated with considerable challenges, such as digestive disorders, reduced growth, increased diarrhoea, and higher morbidity and mortality, which cause major economic losses to the pig industry.
Zinc oxide Zinc oxide (usually at 2,500 ppm zinc) is usually recommended for inclusion during the first two weeks over the weaning period in pigs. It is crucial for the prevention of postweaning diarrhoea (even mortality) and occasionally oedema disease, both associated with infections with Escherichia coli. However, due to its low absorption, around 80% of the
ZnO is excreted in the faeces (Buff et al., 2005) causing a remarkable deterioration in the environment – contributing to adverse effects on environmental microbial diversity.
On the other hand, where therapeutic zinc oxide is not approved
for use, antibiotics are commonly being used to control E. coli infections post-weaning. However, these antibiotics are being banned for their effects on antimicrobial resistance. Can zinc oxide nanoparticles be a better substitute for zinc oxide
in piglet diets?
requires that milk from cows with two Johne’s positive tests is kept out of the bulk tank. In most cases animal health standards are merely a framework
for ‘best-practice advice’ as high standards go hand in hand with high animal welfare and efficient, profitable farming and food production. As consultants, we work together with farmers, farm staff, vets and other industry professionals to proactively manage and improve health and welfare of livestock. Collating all the required paperwork together in a format that can be readily presented to an inspector takes some of the stress out of an inspection however we know from experience that many farmers find paperwork a chore, easily brushed aside to ‘deal with on a rainy day’.
Zinc oxide nanoparticles ZnO nanoparticles normally used in the chemical and pharmaceutical industries (Rasmussen et al., 2010; Zhao et al., 2014), are considered those particles smaller than 100 nanometers (nm). Compared to conventional ZnO used in pharmacological doses in weanling pig diets, the nanoparticulate ZnO has smaller particle size, larger number of particles per unit mass, and higher specific surface area (Raghupathi et al., 2011; Xie et al., 2011), and is more reactive in chemical and biological systems (Milani et al., 2017). Physico-chemical properties of ZnO products used in animal
nutrition show strong differences, which explain variable bioavailability values and antibacterial strength (Animine, 2017) in animals. In ZnO nanoparticles, physico-chemical properties are modified: specific particle size (10 to 15 times higher than conventional sources) and shape, increases the surface of contact with bacteria. In addition, the high porosity of the powder amplifies the antibacterial activity of the zinc oxide nanoparticles (Animine, 2017). Low doses of nano-ZnO may be a feasible substitute for high doses of conventional ZnO in weaned piglets, contributing to reduction in environmental damage.
Efficacy comparison of ZnO nanoparticles to conventional ZnO
1. Nutrient utilization and growth performance As shown in Table 1, the study of Pei et al. (2019) evaluates the effects of dietary zinc oxide nanoparticles (nano-ZnOs) on growth performance and incidences of diarrhoea in weaned piglets. Compared to the control, dietary supplements of nano-ZnO and ZnO improves the average daily weight gain (ADG), average daily feed intake (ADFI), gain:feed ratio (G:F) and villus height to crypt depth ratio in the duodenum and
Table 1. Effects of different levels of ZnO nanoparticles on growth performance and diarrhoea incidence in weaned pigs
Item
ADG (g) ADFI (g) G:F
Diarrhoea rate (%)
Control ZnO (3000 mg/kg)
286 606
0.469 15.2
354 687
0.517 6.4
Nano-ZnOs (mg/kg) 150
300
358 727
387 708
6.5 450
374 676
0.497 0.550 0.555 10.8
3.2 FEED COMPOUNDER NOVEMBER/DECEMBER 2019 PAGE 21
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