In previous research, feed intake and egg production parameters were the most common response criteria that researchers used to measure energy responses in poultry.
Professor Michael Persia in Virginia Tech’s College of Agriculture and Life Sciences began research on energy levels in poultry from a different stand point in 2008–09, when corn prices increased in response to expanded ethanol production as part of the renewable fuel standard. In the quest to identify and validate alternatives to corn as the primary energy source in laying hen diets, a more holistic approach to laying hen metabolism was investigated.
It was discovered that at least over the short term, the amount of energy fed to hens does not affect the number of eggs produced. Hens will produce eggs if they have enough fatty tissue and mass in their reserves to supply the energy to produce them.
“Results suggested that dietary energy has a more pronounced effect on body mass and fatty tissue before more direct performance responses are observed, “Persia said.
“Therefore, hen body weight and composition can be used as a more sensitive measurement of hen energy status than egg production or feed efficiency.”
There search was published recently in the Journal of Applied Poultry Research and is supported by the John Lee Pratt Animal Nutrition Senior Research Scholar Program.
More recently, the cost of dietary oil, the second leading energy component of a diet, has increased with additional biodiesel production. As so, Persia and his team conducted an experiment to evaluate the effects of varying dietary energy on the performance and energy storage in laying hens from 36 to 52weeks of age.
A total of 252 hens were fed one of seven experimental diets ranging in dietary energy from 2,750 to 3,050 kcal/kg. Egg production, energy intake, feed intake, egg weight, egg mass, and feed efficiency were calculated. Hens were weighed every four weeks and carcass total, lean, and fat mass were determined at 52weeks of age using a dual-energy X-ray absorptiometry, a type of evaluation.
Results indicated that dietary energy intake impacted the hens’ total carcass mass and carcass fat mass before altering the number of eggs they produced.
“Although egg production was unaffected, total mass, body weight, and fat mass were significantly decreased with decreasing dietary energy and were directly correlated with dietary energy,” Persia said. “This indicated to us that hens will continue to produce eggs at the expense of energy body reserves over short-term production.”
This discovery could have substantial environmental and economic impact. “Everything we can do to more accurately determine the requirements of these birds will reduce the cost of eggs—efficiency from a feeding standpoint leads to efficiency from an economist and point,” he said.
“There is also a large environmental component to that as well. Anytime we can increase the utilization of energy or nutrients from the diet, that is less that comes out on the back end as manure. If we can more efficiently utilize our resources and put them into the bird or into the egg, that will help the environmental footprint.”
Source: Virginia Tech