Effect of zinc on weaned pigs to be scrutinized

Effect of zinc on weaned pigs to be scrutinized

THE addition of high amounts of zinc to the diet of newly weaned pigs increases the growth rate and reduces the incidence of diarrhea, and now, a researcher from Aarhus University in Denmark will be examining this effect in a new research project.

Today, newly weaned pigs are given a zinc supplement in their diet. By increasing the level from the recommended 100 mg of zinc per kilogram of the diet to 2,500 mg, however, the piglets' weight gain is increased considerably, and the incidence of diarrhea, which is common among piglets, is reduced by up to 50%.

Aarhus department of animal science postdoctoral research Karoline Blaabjerg will be looking more closely at the reason why zinc has the effect that it has.

"The idea behind the project is that the proteins that transport zinc across the intestine are not fully developed in the newly weaned pigs, and they are, therefore, not able to absorb sufficient zinc to meet the demand when the zinc concentration in the feed is 100 mg/kg feed," she explained.

Little research has been conducted about zinc transporters in pigs, but zinc absorption in humans and rodents has been found to be tightly regulated by different zinc transporters in the intestinal cells, Blaabjerg pointed out. It is also known that the physiological mechanisms controlling the development of these transporters are dependent on the zinc intake, and there are indications that age-dependent development also plays a role.

In her project, Blaabjerg will initially identify the presence of different zinc transporters in the pigs' intestinal cells. She will subsequently look at how the mechanisms that control the development of these transporters depend on zinc intake. The same mechanisms will also be examined in relation to ontogenetic (age-dependent) development.

New insights into the mechanisms controlling zinc uptake in newly weaned pigs can be crucial in determining their needs during the critical 14-day postweaning period, thus ensuring the pigs' health, welfare and growth, the announcement said.


Starfish, mussels

Another research project involving Aarhus and the Danish Shellfish Centre is looking into whether starfish and mussels could be used as alternative sources of protein for laying hens and young pigs.

Mussels and starfish fished from the bottom of Danish fjords were added to the feed of six fistulated pigs kept at Aarhus University's research center in Foulum, Denmark.

The reason is that mussels are able to remove nutrients from the fjords and can, therefore, make an important contribution to reducing the impact of pollution on the fjords from, for example, pig farms, the university explained.

Mussel production in Denmark has been modernized, and production costs have declined. The project will examine whether mussels and starfish can be used as an alternative source of protein — in terms of quality — to soybean meal and fish waste and whether it is economically viable to trawl them up from the sea.

"We work from the concept of so-called compensatory farming, where the nutrients leached into the fjords from households, industry and agriculture can be returned onto land in the form of, for example, pig feed using proteins from mussels and starfish," said Jan Vaerum Norgaard, project member and associate professor in the Aarhus department of animal science.

Work is also ongoing to ensure that compensatory mussel farming may allow farmers to buy mussel farms where the nutrients they remove from the fjords can then be offset in their farm nutrient balance sheet.

The trial is designed as a Latin square in which the six pigs are fed a different diet for each week of the six-week study period. The six supplements are: mussel silage, mussel meal, starfish meal, starfish whey, a fish silage and a nitrogen-free diet. Fish silage is made from salmon that has been included in the study as a control or comparison because fish silage consisting of fish remains from the fish industry is normally included in diets for weanling pigs.

Although the trial runs for six weeks, Norgaard said he has already observed that the pigs do not find all of the diets equally appetizing.

"It would appear that starfish whey is not something they particularly relish. Meal of whole starfish, on the other hand, is a reasonable protein source that the pigs seem happy to eat," he said.

Besides being tested on piglets, the mussels and starfish are also tested as a protein source for laying hens.

"If our results show that mussels and starfish are good sources of protein, this could be particularly interesting for organic egg producers because they lack good protein sources," Norgaard said.

The first results from the project are expected before the end of the year.


Swine influenza project

The Pirbright Institute in the U.K. has been awarded £4.4 million to work with researchers from the universities of Bristol, Cambridge and Oxford as well as the U.K. Animal Health & Veterinary Laboratories Agency, The Genome Analysis Centre and industry partner Merial on a long-term study on the transmission of swine influenza.

The U.K. Biotechnology & Biological Sciences Research Council's Swine Flu Dynamics project is a five-year project that, in addition to researching virus transmission, will also assess the effectiveness of different influenza control strategies to improve animal health.

As part of the project, University of Bristol researchers Mick Bailey, professor of comparative immunology, and Dr. Ross Harley, lecturer in veterinary pathology, will characterize the immune response to influenza virus in the respiratory tract and blood of vaccinated and infected animals.

Their research will be used to help interpret results from studies of transmission and virus evolution in vaccinated and infected animals in order to develop robust epidemiological models.

Project leader Dr. Bryan Charleston from The Pirbright Institute said, "These studies will provide essential evidence to design control programs for influenza in pigs. We will look at the efficiency of current methods of control, the level of immunity required in a population to prevent the spread and whether new, broadly cross-protective vaccines are more effective at enhancing animal health and livestock production."

The collaborative research team aims to better understand the transmission dynamics of the virus and the effectiveness of current vaccines and will assess the benefits of different control strategies.

Volume:85 Issue:52

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