Corn preservation method alters growth performance in pigs, finds Chinese study

By Aerin Einstein-Curtis

- Last updated on GMT

Related tags Carboxylic acid Acetic acid Acid

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© iStock.com
Pigs getting a diet with organic-acid preserved corn have higher feed intake and boosted performance, say researchers.

A team of Chinese researchers examined the influence of corn processing techniques on pig growth and development in a series of experiments. They published their results in the journal of Animal Feed Science and Technology​.

“This study was conducted to test the hypothesis that the DE [digestible energy] and ME [metabolizable energy] as well as the apparent ileal (AID) and standardized ileal (SID) digestibility of organic-acid preserved corn is greater than heat-dried corn,” ​said the researchers. “The second hypothesis was that pigs fed diets containing organic-acid treated corn will have improved performance compared with pigs fed diets containing heat-dried corn.”

When used in swine feed, the group found that there was a notable difference between the preservation method used, they said.

“Feeding organic-acid treated corn significantly increased average daily feed intake by 12.5% (604 vs. 539 g/day) compared with heat-dried corn,” ​said the researchers in the study. “In conclusion, the available energy content of organic-acid treated corn was greater than heat-dried corn, and organic-acid treated corn improved weanling pig performance.”

Processing focus

Corn is an often used ingredient in swine diets, said the researchers. However corn quality and corn mold are known to impact pig performance.

Corn preservation methods are being developed to improve corn utilization, they said. Drying is a common method used, but requires higher energy input and alternative methods would be beneficial.

Previous research has established that some organic acids like formic acid and propionic acid can prevent mold development, and improve performance, they said. And, as a feed additive the treatment may support intestinal health.

However, there is little information about how spraying organic acids onto feed during process influences intestinal health, they said. The group sought to establish more information on the ileal digestibility of organic-acid preserved corn.

Experiments conducted

The team conducted three experiments to establish the digestible and metabolizable energy levels and the apparent (AID) and standardized ileal digestibility (SID) of amino acids for corn that had been heat dried or preserved with organic acid.

Additionally, they processed the corn and stored both the heat-treated corn and organic-acid persevered corn in the same location for seven months prior to using it, they said.

In the first experiment, 12 pigs were split into two groups and given a diet including either 970g/kg organic-acid treated corn or heat-dried corn to establish the DE and ME levels in the differently treated corn.

Pigs had a seven-day adaption period and a five-day feeding trial, they said. Feed intake, refusals and spillage were recorded and fecal matter and urine were collected.

In the second experiment, 18 barrows were fitted with t-cannula and given one of three experimental diets, said the researchers. Two of the diets featured the heat-treated or organic-acid treated corn, and the third was nitrogen-free and used to measure losses of crude protein (CP) and amino acids (AA)

Pigs again had a seven-day acclimation period and a five-day feeding test, they said. After the trial period, ileal digesta was collected.

In the final experiment, 60 post-weaning piglets were given one of two diets for a period of four weeks, said the researchers.  

Piglets were weighed at the beginning and end of the experiment and checked daily for diarrhea, they said. Average daily gain, average daily feed intake and the gain to feed ratio were calculated and fecal samples were collected.

Corn, diets, fecal samples and digesta were analyzed for ether extract, Kjeldahl N, dry matter, starch, ash, calcium, phosphorus, amino acids and neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations were established along with gross intake energy (GE), they said. Corn samples also were checked for mycotoxins.  

Results

Chemical analysis of the corn found that the two types had similar compositions, said the researchers. Soluble sugars were higher for treated corn and resistant starch concentrations were larger in the heat-dried corn.

Levels of deoxynivalenol were found in both samples and were higher in the organic-acid treated corn, they said. “There were no differences in the ATTD [apparent total tract digestibility] of GE, DM, or nutrients between the 2 sources of corn,”​ they added.

For the first experiment, the organic-acid treated corn had higher amounts of DE and ME at 16.6 MJ/kg and 16.3 MJ/kg than the heat treated corn, said the researchers. Heat-treated corn had 16.4 MJ/kg for DE and 15.9 MJ/kg for ME.

The second experiment found no major differences in the AID or SID of crude protein and amino acids in the two different corn diets, said the researchers.

For the last experiment, piglets had improved daily gain and higher daily intake if they received corn preserved with organic acid, they said. “The diarrhea index in piglets did not differ between pigs fed heat-dried corn and organic-acid treated corn,”​ they added.

“The performance of weanling piglets fed diets containing organic-acid treated corn was improved compared with piglets fed diets containing heat-dried corn most probably due to the higher feed intake for pigs fed the organic-acid treated corn,” ​they said. “Therefore, treatment of high moisture corn with organic acids may be an attractive alternative to the traditional heat treatment of corn.”

Source: Animal Feed Science and Technology

Title: A comparison of the nutritional value of organic-acid preserved corn and heat-dried corn for pigs

DOI: doi:10.1016/j.anifeedsci.2016.02.016

Authors: X. Xu, H.L. Wang, P. Li, Z.K. Zeng, Q.Y. Tian, X.S. Piao, E.Y.W. Kuang

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