Effect of Feed Grade Animal Fat on Laying Hen Performance and on Metabolizable Energy of Rations

Abstract

The addition of 2 or 4% fat to laying hen rations based on corn, oats, barley or combinations of these grains significantly (P<0.05) decreased feed consumption and improved feed efficiency. There were no adverse effects of added fat on egg production and on livability of laying hens. When no fat was added, the use of combinations of oats and corn (24.2 and 49.2% of the ration, respectively) or barley and corn (24.2 and 49.2% of the ration, respectively) resulted in an increase in egg production and an improvement in feed efficiency in comparison with rations based on corn, oats or barley alone.Added fat was found to have an "extra metabolic effect" whereby the change in ration M.E. caused by fat as measured experimentally exceeded that anticipated on the basis of calculated M.E. of the ration. This effect was mainly observed in rations with 4% added fat and in rations where corn was one of the ingredients. The apparent M.E. of fat, therefore, would approach its gross energy value if this "extra metabolic effect" was entirely attributed to added fat. , 1966. The energy value of fats for growing turkeys. Proc. Xlllth Worlds Poultry Congress, Kiev, Russia, Pg. 190-195. Treat, C. M., B. L. Reid, R. E. Davies and J. R. Couch, 1960. Effect of animal fat and mixtures of animal and vegetable fats containing varying amounts of free fatty acids on performance of cage layers, Poultry Sci. 39:1550-1555. Waring, J. J., R. F. Addison and W. O. Brown, 1968. A comparative study of energy utilization by the laying hen from diets containing a high proportion of fat and diets made up mainly from carbohydrate sources. Brit. Poultry Sci. 9:79-86.

Influence of Dietary Fat on Energy Utilization by Laying Hens

“…There was no incidence of fatty liver hemmorhagic syndrome. In general, the production responses of hens during the current study agree with those reported by Lillie et al, 1952;Gerry, 1963;Sell et al, 1976;and Horani and Sell, 1977.…”

“…The hens were placed in individual cages equipped for collection of excreta. These were used to determine the ME content of the experimental rations according to the procedures described by Horani and Sell (1977).…”

“…The use of fats in laying hen rations has been relatively limited despite the availability of information demonstrating fat's effectiveness for improving efficiency of feed use (Lillie et al, 1952;Gerry, 1963;Jackson et al, 1969;Daghir, 1973;Sell et al, 1976;Horani and Sell, 1977). Sell et al (1976) and Horani and Sell (1977) also have reported that added fat increased ration metabolizable energy (ME) and efficiency of feed utilization by laying hens more than expected on the basis of the commonly accepted ME value of feed grade fats (7500 to 8100 kcal/kg). These researchers found that fats used at 2 to 6% of laying hen rations had an apparent ME equal to or exceeding fat's gross energy content.…”

Effect of Diet Composition on Feed Intake and Growth of Chicks Under Heat Stress

“…It is logical to assume that the beneficial effect of high fat diets on heat stressed chicks results largely from the associative dynamic effect of such diets. There is now sufficient evidence to show that the associative dynamic effect, originally attributed simply to a decrease in heat increment when dietary mixtures contained fat (Forbes and Swift, 1944), may also include a component of increased metabolizable energy (Leeson and Summers, 1976;Horani and Sell, 1977). This has been demonstrated by an increase in determined metabolizable energy over calculated values when low levels of fat were included in the diet.…”

True and Apparent Metabolizable Energy Value of Fat for Laying Hens: Influence of Level of Use

“…The magnitude of improvements is considered to be a reflection of increased metabolizable energy (ME) concentration of the diet. Recently, data have been presented indicating that the generally recognized ME values for feed-grade fats underestimate fat's true energy contribution to practical rations (Touchburn and Naber, 1966;Jensen et al, 1970;Horani and Sell, 1977a). Indeed, Sell et al (1976) and Horani and Sell (1977a,b) found that animal tallow had a ME value approaching or exceeding its gross energy content when used at low levels in laying hen rations.…”