Page 4 - APN July 2017

Pork CRC confronting hot issues with cool science
Kym 0439 066 054 kym@nationalfeedsolutions.com.au
Luke 0439 066 006 luke@nationalfeedsolutions.com.au
Bill 0499 009 293 bill@nationalfeedsolutions.com.au
☛ from P3
the gut microbiome as-
sociated with improved growth performance in E. coli-challenged pigs and more recently, Dr Alison Collins has reported ef- fects of antibiotics and zinc oxide on antimicro- bial resistance and the gut microbiome.
E. coli challenge
Alison investigated the effects of the antibiotic neomycin sulphate and ZnO on the health and an- timicrobial resistance of pigs naturally challenged with E. coli.
I am not an expert in the field, but think the outcomes are fascinating.
The pigs were weaned at 21 days, moved to separ- ate rooms at EMAI and offered a common diet for six days, with the treat- ments starting on day seven.
Neomycin sulphate was added to the experimental diet at 8mg/kg and ZnO at 2500ppm.
The control diet con- tained no antibiotic or ZnO.
The treatments lasted two weeks, after which pigs were offered the same basal diet without
antibiotics or ZnO for a further three weeks.
Control pigs exhibited more diarrhoea than those on all other treatments during the two-week test period and 25 percent of pigs on the antibiotic and ZnO treatments exhibited diarrhoea when the mate- rials were withdrawn.
Dr Collins measured the percentage of E. coli re- sistant to a range of antibi- otics on day six (the start), during the treatment pe- riod and three weeks after treatment.
She also assessed the gut microbiome at the same times.
The effects of treatment on the percentage of E. coli isolates resistant to seven commonly used antibiotics was consistent across antibiotics.
In general, neomycin increased antibiotic re- sistance during treatment but this fell back to very low levels following with- drawal.
ZnO, however, tended to reduce the level of an- tibiotic resistance during treatment but elicited in- creased resistance three weeks after withdrawal, and the increase was sig- nificant for tetracycline.
Using Linco-Spectin as an example – resistance at day six was about 14 per- cent (range 12-17 percent).
Over the two-week treat- ment period, resistance increased from 15-20 percent on the neomycin treatment, stayed relative- ly constant for the control and fell to zero for the ZnO treatment.
Three weeks after treat- ment, resistance on the previous neomycin treat- ment fell to near zero and the control was at 5 per- cent.
For the previous ZnO treatment, resistance had increased from zero to 12.5 percent.
The implications of the apparent increase in anti- microbial resistance fol- lowing the use of ZnO is being further investigated, particularly to see if the resistance was phenotypic or genetic.
The quite large decline in resistance following withdrawal of the neo- mycin is interesting and raises questions of how the change in resistance is driven, its persistence and the relevance of when it is measured.
Results for changes in the gut microbiome fol- lowed a similar pattern to antimicrobial resistance.
Neomycin and ZnO markedly disrupted the gut microbiome during treatment but at a gross level this returned to that of the control levels three
weeks after withdrawal of the antibiotic and ZnO.
The researchers are now looking at changes in the gut bacterial populations in more detail.
As I said, it’s an in- triguing study with may- be more questions than answers – but a sign of where things are heading in the area.
The outcomes also reflect the excellent work being done by researchers across Pork CRC Program 2 ‘Herd Health Management’.
There is much more to come, and we are lucky to have so many good scien- tists in the area – I think we will need them.
Price points
I have summarised the latest global prices in Ta- ble 1.
The US and Canada are enjoying the normal sum- mer increase in demand and prices.
The EU has seen prices increase in the past few months.
In China, price fell again in June and is getting clos- er to COP.
I’m not sure where we’re at in Australia because there is now a marked difference in prices ‘reported’ by buy- ers and sellers.
Prices given are the av- erage of the two.
All seem to have fallen slightly since last month.
To put things in con- text, COP in the US is now about $A1.72/kg car- cass weight, with feed at $A276/tonne.
www.porkcrc.com.au
Country
Price
Comment
Australia*
45-60 kg
3.12
60.1-75 kg
2.90
75.1-85 kg
2.86
85 and above
2.73
US
2.46
Up40c
Canada
2.32
Up40c
Brazil
1.76
Down 20c
China
3.46
Down 43c
Spain
2.85
Up 19c
EU
2.70
Up 16c
www.primegro.com.au
Results are based on typical progeny growth performance achieved using Primegro Genetics grown under a high health environment and fed using the Rivalea Nutritional Program.
Table 1: Latest global pig prices ($A/kg carcass weight) and changes from one month ago. *Eastern seaboard only.
Page 4 – Australian Pork Newspaper, July 2017
www.porknews.com.au
Dr Alison Collins (in red) of Elizabeth Macarthur Agricultural Institute, NSW, has developed, with Pork CRC support, a quantitative PCR to combat ileitis by moni- toring its incidence and treatment effects.
Pork CRC candidate at the University of Sydney, Lechelle van Breda (left) has just completed a very comprehensive study on E coli. She is pictured at Pork CRC’s 2016 stakeholders’ meeting in Melbourne with Pork CRC Chairman Dennis Mutton, Dr Alice Weaver of Myora Farm, Mt Gambier, SA and Tanya Nowland of SARDI.