In High Health Situations Antibiotics may not be Necessary

Posted in: Uncategorized by admin on February 7, 2017

Weaning is a stressful time in a piglet’s life. During this time, they are exposed to three major stressors (nutritional, environmental and social). Combined, these can activate the immune response in the piglet, which in turn can have negative impacts on animal performance immediately post-weaning (low or no feed intake, reduced or negative growth rates). In order to help combat the stress/immune response at the time of weaning, piglets are often fed a diet containing a low level of antibiotics. This helps the piglets cope with any potential secondary infections which may be contracted while their immune system is vulnerable.

 

In April 2015, Health Canada announced that the use of in-feed antibiotics will be phased out over the next three years. Health Canada’s measures are dedicated to strengthening regulation and encourage prudent use of anti-microbial drugs used in food-producing animals, particularly drugs considered medically important.  To date Health Canada has being working with the pharmaceutical industry in phasing out all growth promotion claims related to medically important drugs by December 2016.

 

Finding alternate strategies to help piglets cope at the time of weaning is important, and nutritional modulation for this purpose is a growing area of interest.

Flaxseed is a rich source of omega-3 fatty acids, which are known to have many different health benefits, including anti-inflammatory properties. Omega-3’s can be easily transferred to piglets via the milk when sows are fed diets containing a good quality source. Additionally, changing the fatty acid profile of sow diets by adding omega-3’s can impact the inflammatory responses of their offspring. Perhaps by improving the health of piglets prior to weaning, through nutritional modulation of the sow, it might be possible to remove antibiotics from nursery diets.

 

Trial set up

A total of 103 sows were used for this trial, 52 weaned at four weeks of age and 51 at three weeks of age. Within each weaning group, sows were fed one of two diets (control or with omega-3) throughout lactation. At the time of weaning, ten piglets from each litter were selected, moved to the nursery and housed in two groups of five piglets each (two nursery pens per litter). One half of the litter (1 pen) was fed a starter diet containing antibiotics (LS20, 0.1%), and the other half received the same diet without antibiotics. After one week, all piglets were switched to a common phase 2 diet for the remainder of the study.

 

Due to the high health status of the facility, prior to weaning nurseries skipped a single was cycle in order to create a health challenge;ensuring each weaning cohort was immunologically challenged. Regardless of weaning age, all piglets completed the trial at 56 days of age. Piglet performance was determined in both the farrowing and nursery rooms. Sow milk was collected during mid-lactation to determine the fatty acid profile of the mile being consumed by piglets. Piglet health was monitored by collecting blood for complete blood cell count (CBC) and chemistry blood panels two days post-weaning. A total of 1,181 piglets completed the lactation portion of the trial. Of those, 1,021 piglets were used for the nursery portion.

 

Results and discussion

There were no dietary effects (± omega-3 fatty acids) on sow feed intake, numbers of piglets born, piglet growth or on the number of piglets weaned per litter. As expected, sows fed a diet with added omega-3 fatty acids had significantly more omega-3’s in their milk relative to control sows (5:1 vs. 8:1 n-6:n-3 ratio).

In the nursery, there was no impact of sow diet on average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (G:F) or final body weight for piglets weaned at three or four weeks of age. For piglets weaned at three weeks of age, ADFI was 20 g/d higher during the fourth week in the nursery for piglets who received no antibiotics in their phase 1 diet; however, ADG and feed conversion ratio were not affected. Feed intake was not affected during any of the other weeks on trial for these piglets. For piglets weaned at four weeks of age, ADG tended to be greater in piglets fed diets with antibiotics for week 1 of the trial, which also lead to improved feed conversion ratios during that week.

Growth and feed conversion ratio were unaffected by the inclusion of antibiotics from weeks 2 to 4 in the nursery. Feed intake tended to be higher in antibiotics fed piglets during week 3, and was significantly higher in week 4 relative to piglets who received no antibiotics in the first week post-weaning (930 g/d vs. 900 g/d); however this did not impact grower-finisher. The research team observed no dietary effects (sow diet or nursery diet) on the final body weight of piglets at nursery exit; however, regardless of dietary treatment, piglets weaned at three weeks of age were roughly 1.5 kg heavier than those weaned at four weeks.

No effects were found due to either sow or phase 1 diet on any of the blood measures taken when piglets were weaned at three weeks of age. When piglets were weaned at four weeks of age, piglets weaned from sows fed diets containing omega-3 fatty acids had lower white blood cell counts relative to those weaned from sows fed the control diet. White cell counts were unaffected by phase 1 diet, and neither sow nor phase 1 diet affected any of the other blood parameters measured.

 

Conclusion

The hypothesis of this trial was – feeding omega 3 fatty acids to sows in the form of flaxseed would allow for the removal of antibiotics in starter feeds.  Based on results from this trial, we can neither accept nor reject this hypothesis, as we found that in our high health herd, antibiotics had no post weaning benefit.

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