The objective of the present study was to compare the incorporation of different types of n-3 polyunsaturated fatty acids into thigh muscle lipids of poultry. Nine groups of broiler chicks were fed diets supplemented with three levels (1.0, 2.5, and 5.0%) of either corn, linseed, or menhaden oil. Birds supplemented with linseed oil, rich in linolenic acid (C18:3n-3), had significantly higher levels of n-3 fatty acids and higher n-3:n-6 ratios than those supplemented with the same level of menhaden oil, primarily due to an accumulation of C18:3n-3. Levels of eicosapentaenoic acid (C20:5n-3) were increased (P less than .05), compared with the controls fed the same level of corn oil, in the groups fed the two higher levels of linseed oil, and in all the groups fed menhaden oil. Linolenic acid is less susceptible to auto-oxidation, and is less likely to impart an off-flavor to the muscle. Thus, if it is desirable to increase the n-3:n-6 ratio in poultry, seed meals or oils with a high content of C18:3n-3 could be used in poultry feeds.
Addition of the hypocholesteremic agent Probucol ((4,4'-isopropylidine dithio)-bis(2,6-di-t-butyl-phenol)) to the diet of laying hens at up to 1% significantly reduced egg yolk cholesterol content (mg/g yolk) without impairment of rate of egg production, egg weight, shell strength, albumen quality, or other production related parameters. Dietary concentration of .1% Probucol significantly reduced yolk cholesterol within 2 weeks after feeding. Higher concentrations did not further reduce yolk cholesterol. Probucol at .025% reduced egg yolk cholesterol within 4 weeks after feeding, but after 8 weeks of feeding, eggs from hens fed .025% Probucol did not differ significantly in yolk cholesterol from those fed the basal unsupplemented diet. This suggests possible adaptation in cholesterol synthesis by the laying hen.
Two trials involving 480 Cobb color-sexed broiler chicks were conducted to determine the effect of various constant ambient temperatures on the performance of broilers. Temperatures in Trial 1 were 18 and 29 C and in Trial 2 were 24 and 35 C. The interacting effect of dietary energy (3.142 or 3.252 kcal ME/g of diet) and protein (16, 19, or 22%) on performance criteria was also examined within each trial. There was no indication of selective consumption of any of the ratios at any temperature. Differences in feed consumption observed in either trial were totally contributed by temperature effect. Within a trial, and irrespective of temperature treatment, the rate of growth and feed consumption of the females were less than that of the males. Males and females responded equally to the ambient temperature; there was no significant sex X temperature interaction in Trials 1 or 2.
A series of trials was conducted to determine if adding a Lactobacillus fermentation product (LAC) to the feed of laying hens would improve their production performance. Feeding a liquid, nonviable LAC product to either cage or floor housed laying hens did not improve hen-day egg production, feed efficiency, nor egg size during a 48 week experimental period. Laying hens fed a dried, nonviable LAC product did not show any improvement in hen-day egg production nor feed efficiency compared with laying hens fed no LAC or zinc bacitracin. Addition of a viable LAC product to ratios of differing protein levels did not improve hen-day egg production, livability, or egg size of laying hens.
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