Essential oils, diet may boost piglet growth, gut health

Use of essential oils and nutrient density may improve piglet growth and health absent antibiotics for growth promotion. 

A group of Korean researchers explored the use of nutrient levels and essential oils (EO) in piglet diets to examine digestibility, growth performance and gut health. The group was also interested in tracking the mechanisms that are boosted by essential oil use in a diet lacking antibiotic growth promoters.

“Dietary supplementation with 0.04% EO has beneficial effects on growth performance and apparent ileal digestibility,”​ said the researchers.

Essential oil use​

As regulations increasingly curtail the use of antibiotics in animal production, producers have started to seek alternative options for growth promotion, said the scientists.

“Essential oils (EO), also referred to as volatile or ethereal oils, are a mixture of volatile, lipophilic, largely terpenoid compounds extracted from plant material (flowers, buds, seeds, leaves, twigs, bark, herbs, wood, fruits, and roots), and they have received increased attention as one such potential alternative,” ​they wrote.

Several previous studies have demonstrated the positive results that EO use can establish, including growth promotion and immune function, according to the team.

However, the mechanism underlying the beneficial influence on growth is not yet known, said researchers. And, most work has been done on diets with the same nutrient levels.

“This study was conducted to evaluate the effects of EO supplementation in a normal and decreased nutrient density diet, as well as the main and interactive effects of EO supplementation and dietary nutrient density on growth performance, nutrient digestibility, blood characteristics, and fecal microbial shedding in weaning pigs,”​ they said.

Experiment details​

In the first experiment, 140 weaned pigs were given one of four treatments for 42 days, said the researchers. The diets included a normal and decreased nutrient density and 0 or 0.04% EO. The EO used was a commercial product made by Delacon.

Diets were predominately comprised of corn and soybean meal, they said. Blood was drawn on days 14 and 42 and fecal samples were collected from each pen on days 14 and 42 to establish apparent total tract digestibility (ATTD).

Pigs were weighed on days 0, 7, 21, 35 and 42, and average daily gain (ADG), average daily feed intake (ADFI) and the gain to feed ratio (G:F) were determined.

In the second experiment, four weaning barrows were fitted with T-cannulas at the distal ileum and given one of the experimental diets for a period of 15 days before moving to another diet, they said.

The goal of the project was to evaluate the apparent ileal nutrient digestibility of the experimental diets in weaning pigs, they said. Body weight (BW) was taken at the beginning of each phase.

Fecal and urine samples were collected on days 8 to 13 and digesta was gathered on days 14 and 15, they said

Results​

Pigs getting a diet with normal levels of nutrient density had an increased average daily gain (ADG) and G:F ratio when compared to those on the reduced nutrient density diet, said the researchers.

The ATTD of dry matter (DM)and gross energy (GE) also were higher for pigs getting the diet with more nutrient density, they said. “The ileal digestibility of most amino acids, except threonine, valine, methionine, proline, glycine, alanine, cystine was increased in the normal nutrient density diet,”​ wrote the team.

Pigs getting the EO supplement had an improved ADG and G:F ratio when compared with pigs not getting the feed additive, said the researchers. “EO supplementation diet also showed significant positive effects on the CAID of some amino acids, including isoleucine, leucine, lysine, arginine, aspartic acid, serine, and tyrosine,”​ they added.

The coefficient of apparent ileal digestibility of DM, nitrogen, gross energy and amino acids were improved by both EO and a more nutrient dense diet, noted the team.

“The present findings showed that EO supplementation increased the CAID of DM, nitrogen, GE and amino acids, which suggests that herbal additives improve digestive tract function by increasing the activity of digestive enzymes of gastric mucosa (Chrubasik et al., 2005 and Srinivasan, 2005),” ​said the scientists. “Therefore, we hypothesized that the improvement in ileal amino acid digestibility was related to greater microbial activity in the ileum, which may have led to more bacterial degradation of amino acids after EO treatment.”​

There were no interactive effects seen between EO use and a higher nutrient density in terms of growth performance, digestibility, blood profile or fecal microflora, they said.

“Both dietary EO supplementation and normal nutrient density diets could improve growth performance and ileal digestibility in weaning pigs,” ​concluded the team. “More research is needed to determine the mechanisms of EO in enhancing ileal digestibility in weaning pigs.”​