Tereos scientists talk up animal protein substitutes for piglet and fish feed

Partial replacement of animal proteins by wheat proteins in the diet of piglets and veal calves can boost the animal's growth performance while wheat gluten could also improve the environmental profile of the aquaculture sector, said Tereos Syral at its event on alternative feed proteins last week.

The French company hosted the one-day event in Paris on 10 April to inform the feed sector, it said, of the cost and sustainability benefits of incorporating wheat proteins into feed for various livestock sectors as well as aquaculture. 

Dr Emmanuelle Apper, an animal nutrition scientist with Tereos Syral, speaking at the event, said that hydrolyzed wheat proteins (HWP) are a high-protein source, devoid of anti-nutritional activities, and are highly digestible for young animals. 

HWP are produced from vital wheat gluten by a specific process based on hydrolysis, purification, and drying. 

Apper said as they are a highly concentrated protein source with around 80 percent crude protein, 6 percent fat, 3 percent starch and 1 percent fiber on a product basis, they show good potential for inclusion in starter feed diets.

Feed efficiency with wheat proteins

Several studies performed on post-weaned piglets and on veal calves, said the animal nutrition scientist, showed that the replacement of 5 to 15 percent animal or milk proteins in diets by HWP does not impair performance and feed efficiency, carcass characteristics, blood hematocrit, or diarrhea incidence. 

Apper said a study showed that substituting 10 percent of high quality LT herring meal with 9.5 percent HWP in diets of weaned piglets – at 28 days of age - significantly increased digestibility of dry matter, organic matter, and crude protein calculated within two weeks after weaning.

The same feed, it was reported, increased the digestibility of crude protein three to five weeks after weaning (Blasco et al., 2005). 

Additionally, no significant differences on apparent digestibility of dry matter, organic matter, and crude protein was observed in another piece of research when 8 percent spray-dried porcine plasma was replaced by 8 percent HWP in diets of 21-day old piglets over a 28-day period (Lai et al., 2004).

Wheat gluten in fish feed

Meanwhile, Aurélien Feneuil, application scientist at Tereos Syral, talked up the nutritional and technological benefits of using vital wheat gluten (VWG) in fish feed.

Pressure is growing on the aquaculture sector to find alternative protein sources with the supply of fish meal diminishing rapidly. 

VWG has an interesting amino acid profile, said the scientist, with a high level of glutamine and sulphur amino-acids. 

Feneuil said that anti-nutritional activities are not observed when wheat gluten is used as a fish meal replacer. 

And he added that growth performance and feed efficiency are not modified when up to 50 percent of fish meal is replaced with VWG in the diet of salmon, trout and sea bream. 

When compared with soybean-meal, VWG does not damage gut structure in Atlantic salmon, said Feneuil. 

Extrusion of wheat gluten pellets

But there are extrusion challenges, said the Tereos Syral scientist, with the company recently having evaluating processing methods, looking at the extrusion behavior of three salmon feed formulations with various percentages of soy protein concentrate being replaced with VWG. 

Feneuil said the company found that increasing wheat gluten content in the fish feed formulation brings benefits for both the extrusion process and pellets characteristics, with increased production capacity, increased pellet hardness and reduced fat leakage the result.

A higher inclusion of wheat gluten content in the formulation leads to a decrease in motor load (Draganovic et al., 2011) due to the lower water holding capacity of wheat gluten compared to soy protein concentrate.  

This reduction in motor load when increasing wheat gluten inclusion is a huge process advantage which directly reduces energy consumption during extrusion,” said the French scientist.