Barnyard Roundup: Potential oilseeds; milk fat; fish feed

Holstein cows shown at the Penn State Dairy Barns. Milk fat is a main contributor to the value of milk, but it is also the most variable component because it is very responsive to diet and management,  Credit: Penn State. Creative Commons

As the name suggests, oilseed crops are grown for their oil content — think soybeans, sunflowers, and canola, and the resulting protein meal products are a bonus that the livestock industries rely on in their nutritional programs.

Now, a University of Nebraska-Lincoln researcher is leading a team working to unlock the full potential of two oilseeds that may help meet the escalating demand for renewable fuels, industrial chemicals and other bioproducts. The team will produce genetically enhanced oilseeds, establish the “rules” of oilseeds’ metabolic circuitry and develop synthetic biology tools for crop improvement that could help scientists across the country.

With a five-year, $12.8 million grant from the U.S. Department of Energy, Nebraska biochemist Edgar Cahoon will lead an interdisciplinary team representing eight institutions in exploring how camelina and pennycress, which contain the fatty acids necessary for producing biofuels and biomaterials, could help replace petroleum-based products and mitigate the effects of climate change. The project will pave the way for wider use of oilseeds in environmentally friendly and sustainable applications.

“Looking to the future, we think that cars will be electrified, but there will still be demand for liquid fuels for jets, tractor-trailers and heavy equipment. We’re looking for renewable sources for these types of liquid fuels,” said Cahoon, the George W. Holmes professor of biochemistry. “And those feedstocks can also be used for chemical applications, like making bioplastics and lubricants with better properties.”

The project focuses on pennycress and camelina, members of the mustard (Brassicaceae) family, because these plants do not compete with food crops. The oilseeds are also resilient, with the ability to grow as winter cover crops or on marginal or underused land, the university said.

Pennycress and camelina oilseeds aren’t ideal precursors for bioproducts yet. Their oil content is suboptimal — roughly 30% of their seed weight is oil, falling short of the 40%-plus target — and they contain a less-than-ideal mixture of fatty acids. Cahoon’s team aims to change both characteristics.

Cahoon said he expects the team’s work to have impacts beyond pennycress and camelina. Findings related to the plastid’s metabolic circuitry, as well as the synthetic biology tools, will be valuable to scientists pursuing next-generation engineering of other plant oil feedstocks.

Separately, other researchers have been studying feeding protein meals derived from camelina and pennycress to livestock, which will be important once these crops become more available.

Milk fat

Penn State animal scientist Kevin Harvatine has received a four-year, $650,000 grant from USDA’s National Institute of Food & Agriculture to study the regulation of fatty acid metabolism in dairy cows with the goal of boosting revenues and efficiency on farms by increasing milk fat and optimizing use of dietary fat in cow rations, the university said in an announcement.

Milk fat is a main contributor to the value of milk, but it is also the most variable component because it is very responsive to diet and management, Harvatine noted.

“Feeds high in fat, such as oilseeds or fat supplements, have increased in price and are expensive to feed to dairy cows,” he said. “Cows need some dietary fat to make milk fat, but optimal feeding levels are not established. We believe there is an optimal feeding level for dietary fat that will maximize milk fat by providing some of the fatty acids needed to make milk fat without decreasing synthesis of fatty acids in the udder from other nutrients.”

The objectives of the research are to quantify adaptations in the transfer of fatty acids in the diet of dairy cows to milk fat; to determine the dynamics of fatty acids synthesized in cows’ mammary tissue to milk fat; and to characterize enzyme activity in cows’ fat tissue and its regulation by the secretion of hormones known to impact lactation.

The research will provide fundamental insight into the supply of fatty acids to the mammary gland for milk fat synthesis and identification of key interacting nutritional and cow physiological factors that impact milk-fat yield, Harvatine explained.

“This information will allow establishment of recommended feeding levels for dietary fat and identification of limitations in fat synthesis due to nutrient levels in the cows’ diet,” he said.

“That knowledge eventually will guide dairy producers in attaining optimal fat yield in milk they produce in the most efficient and cost-effective manner.”

Alternative fish feed

A University of Saskatchewan research team is partnering with an array of industry groups to establish a “globally unique” facility on campus to develop and test plant- and insect-derived proteins to replace fishmeal in aquaculture diets.

“Protein by far is the number-one ingredient that determines fish growth rate,” said Dr. Lynn Weber, professor of veterinary biomedical sciences at USask’s Western College of Veterinary Medicine and co-leader of the project. “It is the number-one cost in feed, and feed is the number-one cost in aquaculture.” 

Declining wild fish stocks are driving up consumer demand for commercially grown fish and seafood, and with it the need for cheaper and environmentally sustainable alternatives to fishmeal, Weber said.

To reduce costs, feed manufacturers have looked to soy protein as an alternative to fishmeal, she said, but the demand for soy as a human food has made it expensive. Soy also contains anti-nutritional factors that damage fish guts unless the beans are processed to remove the harmful elements.

Ingredients such as fava beans and peas provide a better protein alternative, said Weber, who has done research with colleagues such as Dr. Matt Loewen on using novel processing methods such as fermentation with yeast, to remove anti-nutritional factors from legumes. Research by some team members using insect protein derived from sources such as fly larvae also appears promising, she said.

USask, situated in the heart of a province that produces an abundance of peas, fava beans and other potential feed ingredients, is uniquely equipped to host the proposed Aquafeed Testing Facility, Weber said.

The University of Saskatchewan has expertise in feed ingredient development and processing, as well as toxicology, environmental studies, artificial intelligence (AI) and animal physiology, nutrition and behavioral science.

“The (Aquafeed Testing Facility) will have some basic research aspects to do with nutrition, eco-toxicology and AI, but basically it will be a contract facility where we hope to bring in industry partners and charge them to develop new feed ingredients and feeds for aquaculture,” Weber said.

The 10-member multidisciplinary faculty team is seeking $3.7 million from the Canada Foundation for Innovation, which is 40% of the $9.3 million needed to revamp USask’s current Toxicology Centre to house the new facility. Provincial and federal agencies, USask, and vendor in-kind support are expected to contribute $5.6 million.

The flow-through fish tank system in the current toxicology center will be replaced with a recirculating aquaculture system with a large biofilter that will cut water use by as much as 90%, she said. 

Each of the 30 new feed testing tanks will be capable of holding 20 or more market-sized fish such as trout and tilapia and will be equipped with continuous water quality sensors and in-tank cameras to closely track feeding rates, responses to novel feed ingredients, behavior, and growth, using AI technology. As well, the rest of the facility will have other, larger tanks to hold fish not currently on trial.