Effect of Animal Fat and Mixtures of Animal and Vegetable Fats Containing Varying Amounts of Free Fatty Acids on Performance of Cage Layers

Abstract

there was no effect on total egg production of any of the breeds over a 40-week period from September through June. The White Rock and Rhode Island Red strains were more sensitive than the strains of the other two breeds in terms of transitory decreases in egg production, especially when the laying pullets were debeaked in January. A decrease in body weight which persisted throughout the post-operative period was observed immediately after each group was debeaked. The inconsistency of the body weight pat-terns between the two experiments may be partially explained on the basis of the intermingling of debeaked and normal individuals in the second experiment. REFERENCES Guhl, A. M., 1956. Peck-orders established in spite of debeaking. Am. Poultry J. 87(10): 4. Hale, E. B., 1948. Observations on the social behavior of hens following debeaking. Poultry Sci. 27: 591-592. Morgan, W., 1957. Effect of day-old debeaking on the performance of pullets. Poultry Sci. 36: 208-210.C ONSIDERABLE work has been carried out within the past few years on the use of animal and vegetable fats as an energy source for growing chickens. Studies on the use of fats in the diets of laying hens have been somewhat limited, however, although the relationship of energy to egg production has been investigated. Heuser et al. (1945) showed that a ration low in fiber content produced a higher rate of egg production than similar rations high in fiber. Quisenberry et al. (1949) andSkinner et al. (1951) presented evidence that increased egg production and improved feed efficiency could be obtained through the use of high energy (low fiber) type diets. Bird and Whitson (1946) fed laying rations 'Present address: University of Arizona, Tucson, Arizona.of both low and high fiber content and found that the productive efficiency was related inversely to the fiber content. Singsen et al. (1952) andGerry (1954) reported that less feed was required to produce a dozen eggs with laying rations of high energy content (low fiber) than laying rations low in energy (high fiber). Hill et al. (1956) reported that increasing the energy level of the laying ration by the use of fat reduced the feed required for egg production at a rate of 2 % for each 1 % of added fat. Hill et al. (1954a, b) markedly decreased the amount of feed required per dozen eggs produced when the caloric density of the diet was increased from 740 to 930 Calories per pound. Price et al. (1957) found that feed required per dozen of eggs was reduced by increasing the energy content of the diet. McDaniel et al. (1957) observed at NERL on April 11, 2015 http://ps.oxfordjournals.org/ Downloaded from

Regulation of plasma oestrogen by dietary fats in the laying hen: Relationships with egg weight

“…1). Other authors have not observed effects on egg weight of feeding tallow at rates of 25 to 30 g/kg Jensen et al, 1958;Treat et al, 1960) or cod liver oil fed at 20 g/kg (Balnave, 1970). The present results suggest that dietary fats are more generally effective in influencing egg weight than has been thought previously, though to different degrees, and that maximum responses are achieved with supplemental concentrations of about 40 g/kg…”

“…Dietary supplementation with animal fats has been less effective (Shutze et al, 1958;Treat et al, 1960) and the overall effect has usually been attributed to some property of linoleic acid. There have been suggestions that olive oil (rich in oleic acid) can be as effective as other vegetable oils rich in linoleic acid (Shannon and Whitehead, 1974;Whitehead, 1981), although these have not been supported by other observations (Scragg et al, 1987).…”

Influence of Constant Elevated Temperature and Diet on Egg Production and Shell Quality

“…Treat et al (1960) reported that addition of fat to laying rations increased egg weight. More recently, Kondra et al (1968) reported that addition of soybean oil to laying diets significantly increased egg weight.…”

Effect of a High Fat Diet Fed Prior to or at Sexual Maturity on Egg Weight ,

“…Ovary and liver weight and the lipid content of the liver were significantly greater for the CON treatment than for the HF or CHO-HF treatments. Previously, Treat et al (1960) and Marion and Edwards (1962) reported that liver weight and lipid content are decreased with corn oil feeding compared with effects of feeding a low fat (1.0%) basal diet. In the present study, the decreased ovary plus ovum weight of pullets in treatments receiving a high fat diet was unexpected, as these treatments produced signifi-cantly greater egg weights.…”