Featured Research

from universities, journals, and other organizations

Tryptophan-enriched diet reduces pig aggression

Date:
March 21, 2010
Source:
USDA/Agricultural Research Service
Summary:
Feeding the amino acid tryptophan to young female pigs as part of their regular diet makes them less aggressive and easier to manage, according to a new study.

Feeding the amino acid tryptophan to young female pigs makes them less aggressive and easier to manage, according to a study by ARS scientists and cooperators.
Credit: USDA

Feeding the amino acid tryptophan to young female pigs as part of their regular diet makes them less aggressive and easier to manage, according to a study by Agricultural Research Service (ARS) scientists and cooperators.

Related Articles


The tryptophan-enhanced diet reduced aggression and overall behavioral activity among young female pigs during the 8-month study. Tryptophan, which is only acquired through diet, is the precursor for the calming cerebral neurotransmitter serotonin. Keeping swine calm is important, because aggressive behavior can harm them and increase feed and medical costs for producers.

The study was done by ARS doctoral student Rosangela Poletto and animal scientist Jeremy Marchant-Forde at the ARS Livestock Behavior Research Unit in West Lafayette, Ind. Collaborators included biologist Heng-Wei Cheng at the ARS lab in West Lafayette, and Purdue University scientists Robert L. Meisel and Brian T. Richert.

The supplemented diet raised blood concentrations of tryptophan in 3-month-old females by 180 percent, and by 85 percent in 6-month-old females, resulting in calmer animals, mainly at the younger age. Persistent aggression in pigs can cause chronic stress, leading to poorer welfare, increased disease susceptibility and reduced growth and efficiency.

In the study, a diet with 2.5 times the normal amount of tryptophan was fed for one week to grower pigs (3 months old) and finisher pigs (6 months old). Another group of pigs received a normal diet. Behavioral activity and aggressiveness were measured before and after the seven days of diet supplementation.

To test aggression, researchers put an "intruder" pig in the pen until an aggressive interaction was triggered or for a maximum of five minutes. Pigs receiving the high-tryptophan diet showed less aggression -- fewer attacked the intruder, and those that did attack were slower to do so -- compared with the animals that didn't get the supplement.

Pigs form social groups that, over time, form stable hierarchies or "pecking orders." However, when new individuals are introduced, aggression is used to re-establish a new hierarchical order. If repeated changes in group composition occur, persistent aggression may arise, sometimes leading to physical injury and acute stress. A tryptophan-enriched diet may help producers avoid these problems, especially when groups of pigs are mixed together.

The research was published in the journal Applied Animal Behaviour Science.


Story Source:

The above story is based on materials provided by USDA/Agricultural Research Service. Note: Materials may be edited for content and length.


Cite This Page:

USDA/Agricultural Research Service. "Tryptophan-enriched diet reduces pig aggression." ScienceDaily. ScienceDaily, 21 March 2010. <www.sciencedaily.com/releases/2010/03/100318141620.htm>.
USDA/Agricultural Research Service. (2010, March 21). Tryptophan-enriched diet reduces pig aggression. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2010/03/100318141620.htm
USDA/Agricultural Research Service. "Tryptophan-enriched diet reduces pig aggression." ScienceDaily. www.sciencedaily.com/releases/2010/03/100318141620.htm (accessed October 25, 2014).

Share This



More Plants & Animals News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins