The team of Brazil-based researchers explored the use of the feed additive in comparison to supplemental colistin on pig growth, digestion, diarrhea and intestinal development for weanling pigs. They published their work in the journal Animal Feed Science and Technology.
“The purpose of this study was to evaluate the effects of dietary graded levels of hop β-acids or colistin (antimicrobial growth promoter) on growth performance, nutrient and energy digestibility, diarrhea occurrence, frequency of unthrifty pigs, respiratory burst, organ weights, and intestinal histology and microbial diversity of weanling pigs, as well as to study in vitro bacteria sensitivity to hop β-acids,” team members said.
The group found that that the non-antibiotic supplement improved body weight, average daily gain, digestibility of ether extract and the gain to feed ratio for young pigs, members said in the study. Similar growth performance was seen for pigs getting the hop b-acids and colistin.
“Dietary hop β-acids concentrations up to 360mg/kg improved weanling pig growth rate by affecting the efficiency of feed utilization, as well as observed for colistin,” they said. “However, further studies are required to understand the mechanisms of hop β-acids action focusing on anti-inflammatory activity and lipid metabolism.”
Why hop b-acids?
The post-weaning period is linked to several production problems for young pigs including poor nutrient absorption, limited digestion, anorexia, diarrhea and reduced growth rate, the researchers said. Non-therapeutic amounts of antimicrobials have been used to address the issues, but increasing concerns about antibiotic use mean alternatives are needed.
Hop β-acids or humulus lupulus L. Cannabaceae, have been found to improve growth performance in poultry, they said. Previous research also has demonstrated an antimicrobial action against clostridium perfringens in broiler chickens.
“Properties being attributed to hop β-acids also include antiviral (Buckwold et al., 2004), anti-inflammatory ( Bortoluzzi et al., 2016 and Tang et al., 2011), antioxidant (Tagashira et al., 1995), antidepressant (Zanoli et al., 2005), and anticancer (Lamy et al., 2007),” they said. “In addition, hop bitter-acids have shown to affect lipid metabolism by improving hepatic fatty acid β-oxidation (Shimura et al., 2005) and reducing adipose tissue ( Sumiyoshi and Kimura, 2013 and Yajima et al., 2004) in mice.”
But, no research has been done testing the feed additive for use in swine, said the researchers. “Based on these findings, we hypothesize that hop β-acids are able to improve the intestinal health and growth performance of weanling pigs,” they added.
Trial details
In the study, 200 21-day old weaned pigs were given one of five diets for 35 days, said the researchers. The diets included a corn-soybean meal basal diet with 0, 120, 240 or 360mg/kg hop β-acids and the feed with 40mg/kg colistin.
On days 7 and 35 sample pigs were harvested to measure organ weights, small intestine histology and intestinal microbial diversity, they said. Pigs were weighed on days 0, 7, 21 and 35 and average daily gain (ADG), average daily feed intake (ADFI) and the gain to feed ratio (G:F) were determined.
Total track apparent digestibility (TTAD) was established for both nutrients and energy and blood samples were taken, they said. Pigs were watched for signs of diarrhea, anorexia and condition.
Additionally, the antimicrobial activity of hop β-acids against Escherichia coli, Salmonella enteritidis, Salmonella typhimurim, Enterococcus faecalis, and Staphylococcus aureus was analyzed, said the researchers.
Results
Increasing amounts of hop β-acids in the diet boosted BW, ADG, and G:F linearly, the researchers said. It also improved the digestibility of ether extract.
The colistin supplement improved BW, ADG, and the gain to feed ratio, but did not alter digestibility for either nutrients or energy when compared to the negative control, they said. No growth performance difference was found between the two feed additives at any level.
Instances of diarrhea were lower for pigs getting the 360mg/kg hop β-acids diet, the colistin supplement and the negative control feed when compared to the other two diets, they said. And, no influence on ADFI was noted.
“No effect of dietary treatments on blood respiratory burst, organ weights, small intestine histology, and intestinal microbial diversity was observed,” the researchers said.
Staphylococcus aureus was found to be sensitive to the hop β-acids, but E.coli, salmonella enteritidis, salmonella typhimurim and enterococcus faecalis were not, they said.
Source: Animal Feed Science and Technology
Title: Effects of dietary hop β-acids or colistin on the performance, nutrient digestibility, and intestinal health of weanling pigs
DOI: published online before print: 10.1016/j.anifeedsci.2016.04.007
Authors: M. Sbardella, D. Perina, C. Andrade, C. Santos, P. Cairo, E. Marques, R. Rezende, L. Costa, V.S. Miyada