Indian researchers, writing in the journal PLoS One, found a significant hike in the abundance of beneficial microbes with pigs given feed supplemented with inulin or ginger compared to an unsupplemented control group or pigs given feed comprising the antibiotic tetracycline.
“The results suggest the potential of ginger and prebiotics to replace antibiotics in the diets of grower pigs,” said the scientists, based at the National Institute of Animal Nutrition and Physiology in Bangalore.
Over the last two decades, noted the authors, there has been widespread interest in developing feeding strategies to improve the gut health in food animals while minimizing in-feed antibiotic usage.
The driving factor for such effort is the emerging evidence that antibiotic administration has a negative impact on host microbiota, immunity and health, and may spread the antibiotic resistance gene to pathogens, said the researchers.
They note that prebiotics have the ability to modulate gut health through an array of interactions with the intestinal epithelium, mucus layer, immune system and microbiota and that ginger residue is effective in inhibiting the growth of pathogens.
Nevertheless, the researchers said there are still knowledge gaps around the response of gut microflora in pigs to either herbal residue or prebiotic is incomplete and inadequate.
So they carried out the current study to assess the shift in hindgut microflora composition in grower pigs as a result of adding either tetracycline, ginger or the prebiotic, inulin.
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Sixteen crossbred pigs with an average body weight of 15.8 kg were divided into four equally sized groups. The animals were maintained for three months on basal diet comprising of maize 54 parts, soybean meal 22 parts, de-oiled rice bran 21 parts, mineral mixture 2 parts and salt 1 part.
The animals had free access to feed and water during the experimental period.
The animals in the control group were offered the basal feed without any additives. In contrast, the basal diet was supplemented with 0.25% tetracycline, 2% ginger residue - powder of ginger rhizome after juice extraction - or 2% inulin in the trial groups.
Fresh fecal samples were collected from each animal after three months of feeding to study the microbial community composition in each group.
The scientists said the compositional changes in microflora communities were assessed by terminal restriction fragment length polymorphism ( T-RFLP) analysis due to their belief this technique is highly reproducible and enables a ‘snap shot’ view of the complex bacterial population of the gut at any particular time.
“Using the T-RFLP technique, we demonstrated a significant shift in the gut microbial composition in grower pigs in response to inulin, ginger and tetracycline supplementations as compared to [the] control,” said the scientists.
The results indicated a significant increase in the abundance of the beneficial microbes Bacteroides intestinalis, Selenomonas infelix, Selenomonas sp. and Eubacterium oxidoreducens with inulin or ginger supplementation as compared to control or tetracycline supplementation.
Additionally, inulin supplementation alone significantly increased the abundance of the beneficial microbes Methylobacterium sp. and Eubacterium oxidoreducens as compared to the control or tetracycline groups.
“Interestingly, a significant reduction in the abundance of the pathogenic microorganisms was evident with the supplementation of inulin or ginger as compared to control or tetracycline,” added the authors.
They concluded that supplementing the diets of grower pigs with inulin and ginger was an effective way to establish a favorable gut microbial composition: “Our findings agree with the hypothesis that herbal residue or prebiotic can be used as an effective alternative to replace antibiotic in the feed of grower pigs.”
Source: PLoS One
Published online 2015 Jul 15. doi: 10.1371/journal.pone.0132961
Title: Assessment of Fecal Microflora Changes in Pigs Supplemented with Herbal Residue and Prebiotic
Authors: A.K. Samanta, C. Jayaram, N. Jayapal, N. Sondhi, A.P. Kolte, S. Senani, M. Sridhar, and A. Dhali