Differences in fatty acid metabolisms in domestic animals: some dilemmas and ideas to address body composition and obesity control

Relatively high amounts of fats or oils (mayor que 40-50 g/kg diet) are frequently used in animal nutrition. Vegetables oils are richer in polyunsaturated fatty acids than animal fats. Most of the works studying the effect of different dietary fat sources are focused either on the existing differences on fat digestibility depending on their fatty acid composition (Wiseman et al., 1991) or on their effect on the carcass fat fatty acid profile (Sanz et al., 1999a). lnformation regarding the effect of dietary fat saturation on fat utilization and deposition it is more limited. lt is generally assumed that, apart from differences in digestion, fatty acids of different composition are equally used for metabolic purposes.

Reproductive long-term effects, endocrine response and fatty acid profile of rabbit does fed diets supplemented with n-3 fatty acids

The effect of a diet enriched with polyunsaturated n -3 fatty acids (PUFA) on endocrine, reproductive, and productive responses of rabbit females and the litters has been studied. Nulliparous does ( n = 125) were fed ad libitum from rearing to second weaning two diets supplemented with different fat sources: 7.5 g/kg lard for the control diet (group C; n = 63) or 15 g/kg of a commercial supplement containing a 50% ether extract and 35% of total fatty acids (FAs) as PUFA n -3 (Group P; n = 62). Dietary treatments did not affect apparent digestibility coefficients of nutrients, or reproductive variables of does including milk pro- duction, mortality and average daily gain of kits over two lactations. However, on Day 5 and 7 post-induction of ovulation, progesterone of Group P tended to increase to a greater extent than in does of Group C. Total PUFAs, n -6 and n -3 and eicosapentanoic (EPA) contents were greater in adipose tissues of does in Group P than in Group C. Docosapentaenoic acid (DPA), EPA, and docosahexaenoic acid (DHA) concentrations were greater in peri-ovarian than in scapular fat with abdominal fat being intermediate in concentration. In PUFA sup- plemented does, kit mortality at the second parturition tended to be less than in control does. Also, kits born to does of the PUFA-supplemented group weighed more and were of greater length than from does of control group. In conclusion, effectiveness of dietary intervention on reproductive and performance response is greater in the second parity, which suggests an accumulative long-term beneficial effect of n -3 FA supplementation in reproductive rabbit does

Palaeoenvironmental reconstruction of Las Conchas Mire (Asturias, N. Spain) from the ketone and fatty acid record= reconstrucción paleoambiental de la Turbera de las Conchas (Asturias, N. España)a partir del registro de cetonas y ácidos grasos

Se han estudiado los biomarcadores, principalmente cetonas y ácidos, preservados en el registro de 3.2 m de la Turbera de Las Conchas. Las cetonas reflejan cierta actividad bacteriana desde 94 cm hasta la base del registro, Los ácidos grasos reflejan una buena preservación de la materia orgánica, salvo en los 20 cm superiores en los que hay indicios de oxidación microbiana de alcanos .The biomarkers, mainly ketones and fally aclds, preserved In 3.2 m deep Las Conchas Mire have been studied, Kelones reflect certain bacterial activity from 94 cm to the bottom of the record. Falty aclds indlcate a good preservation of the organlc matter, wlth the exception of the uppermost 20 cm In whlch mlcroblal oxldation of alkanes are likely to occur

Production of biodiesel from animal fat using supercritical ethanol

Biodiesel is currently produced from a catalytic transesterification reaction of various types of edible and non-edible oil with methanol. The use of waste animal tallow instead of edible oils opens a route to recycle this waste. This material has the advantage of lower costs but the problem of high content of free fatty acids, becoming necessary a pre-esterification reaction that increases the cost of the catalytic process. The production of biodiesel using supercritical alcohols is appropriate for materials with high acidity and water content, therefore the use of this process with animal fat is a promising alternative. Ethanol has been used because it can be produced from biomass via fermentation resulting in a complete renewable biodiesel, instead of methanol that derives from fossil feedstocks. Two different processes have been studied: first, the direct transesterification of animal fat using supercritical ethanol and second a two-step process where the first step is a hydrolysis of the animal fat and the second step is the esterification of the resulting fatty acids. The temperature, the molar ratio ethanol:fat and the time have been modified in the different reactions to study the effect in the final conversion and the degradation of the unsaturated fatty acid esters, main inconvenient of these high temperature and pressure processes.

Blends of babassu, palm kernal and coconut mame with fossil kerosene: low carbon number methyl esters as a possible source for renewable jet fuel

Three different oils: babassu, coconut and palm kernel have been transesterified with methanol. The fatty acid methyl esters (FAME) have been subjected to vacuum fractional distillation, and the low boiling point fractions have been blended with fossil kerosene at three different proportions: 5, 10 and 20% vol.

Oxygen extended sooting index of FAME blends with aviation kerosene

The use of biofuels in the aviation sector has economic and environmental benefits. Among the options for the production of renewable jet fuels, hydroprocessed esters and fatty acids (HEFA) have received predominant attention in comparison with fatty acid methyl esters (FAME), which are not approved as additives for jet fuels. However, the presence of oxygen in methyl esters tends to reduce soot emissions and therefore particulate matter emissions. This sooting tendency is quantified in this work with an oxygen-extended sooting index, based on smoke point measurements. Results have shown considerable reduction in the sooting tendency for all biokerosenes (produced by transesterification and eventually distillation) with respect to fossil kerosenes. Among the tested biokerosenes, that made from palm kernel oil was the most effective one, and nondistilled methyl esters (from camelina and linseed oils) showed lower effectiveness than distilled biokerosenes to reduce the sooting tendency. These results may constitute an additional argument for the use of FAME’s as blend components of jet fuels. Other arguments were pointed out in previous publications, but some controversy has aroused over the use of these components. Some of the criticism was based on the fact that the methods used in our previous work are not approved for jet fuels in the standard methods and concluded that the use of FAME in any amount is, thus, inappropriate. However, some of the standard methods are not updated for considering oxygenated components (like the method for obtaining the lower heating value), and others are not precise enough (like the methods for measuring the freezing point), whereas some alternative methods may provide better reproducibility for oxygenated fuels.