Benefits of minerals in poultry layer rations

Organic mineral sources for layers offer a number of valuable benefits over inorganic trace minerals, according to Aidan Leek, technical manager with layer breeder Hy-Line UK.

They have the potential for improved breeder productivity, egg enrichment and a beneficial synergy with the enzyme phytase.

In addition, there is the opportunity to reduce the environmental impact of mineral excretions and improve food chain safety.

“As nutritionists working in the field we tend to talk about energy and protein levels,” says Dr Leek. “Minerals tend to be in the premix bag, and not changed very often unless there are specific issues within the flock.

“However, they are critically important for ensuring we are efficiently producing quality product from a healthy hen.”

There are about 15 trace minerals considered to be important in diets, of which iron, zinc, copper, maganese, iodine and selenium are always included in premix supplements, (see table).

A further three are sometimes included, while the remaining six are considered to be adequate in the background in general feed ingredients.

Performance gains

“In terms of breeder performance, increasing these minerals within the egg will help embryo development, hatchability and chick quality,” says Dr Keek. “There could also be longer term benefits in the performance of progeny.”

They are also critical to egg shell formation, giving direct benefits in terms of shell strength and elasticity.

As well as the performance benefits, there are also potential marketing benefits, through offering enriched levels of minerals in the eggs.

For example, it is relatively easy to increase levels of selenium and iodine simply by incorporating more in the diet.

But it is more difficult to get a response in egg concentrations with iron, copper and manganese using inorganic sources, because they are regulated according to homeostatic requirements, the bird maintaining a set internal level.

Phytase

Another factor in mineral supplementation is phytase, which is an important nutritional tool for releasing not only bound phosphorous, but also calcium, zinc, sodium, magnesium and amino acids.

“High levels of trace minerals can reduce the efficiency of phytase, by blocking the action on phytate,” says Dr Leek.

In a study using Hy-Line brown layers, phytase fed with inorganic trace minerals at 100% of the NRC recommended level gave a reduced shell percentage. Zinc and iron had the most inhibiting effect.

With organic trace minerals at the 100% level there was no negative effect and, as a result, it was possible to use much lower levels to get the same result. In effect, 7.5ppm of organic zinc was equivalent to using 40ppm of zinc sulphate.

“As nutritionists we are looking at ways we can improve availability and efficiency. Recent work has been done commercially with companies involved in organic trace minerals, which is providing the information on where we need to be on trace mineral supplementation.

“It is important to balance the trace minerals within the diet appropriately and avoid antagonistic effects, such as between zinc and copper. We must use phytase appropriately, and do everything to optimise gut health, to aid efficient digestion.

“We should be looking at supplies that maximise absorption, keeping in mind the economy of doing so.”

Retention rates for inorganic sulphates varies from 20% for copper to 7% for zinc, he says. “Inorganic minerals are supplying a lot of trace minerals to the birds which they are not retaining.”

However, organic trace minerals have different pathways of absorption resulting in increased uptake.

* The above paper is take from a presentation given by Aidan Leek at a recent symposium organised by Novus.

15 COMMON TRACE MINERALS IN RATIONS

Always included: iron, zinc, copper, manganese, iodine, selenium

Sometimes included: molybdenum, cobalt, chromium

Not included: flourine, nickel, vanadium, silicon, tin, arsenic

Better absorption rate for Mintrex

Mintrex organic minerals from Novus offer zinc, copper and manganese chelated with two methionine analogues, explains Novus technical sales manager Sven Keller.

These were only recently registered in the EU, and to date are the only ones currently available offering methionine hydroxyl mineral chelates.

Company trials show that Mintrex Zn, for example, has around four times the absorption rate of zinc sulphate. They have a particular benefit in that methionine inclusion levels in the diet could be reduced due to the methionine content of the supplement.

Commercial benefits are wide ranging, according to Dr Keller, and include a rise in egg production of 4.3% in one trial compared with inorganic minerals at the same inclusion level, using Mintrex 40Zn:10Cu:40Mn.

Other work demonstrates improved response to vaccines for IB and Newcastle disease; a healthier digestive tract (measured as gut wall shearing strength); and higher resistance against oxidative stress.

There are also improvements in egg shell quality, says the company.