The scope for manipulating the polyunsaturated fatty acid content of beef:a review

Since 1950, links between intake of saturated fatty acids and heart disease have led to recommendations to limit consumption of saturated fatty acid-rich foods, including beef. Over this time, changes in food consumption patterns in several countries including Canada and the USA have not led to improvements in health. Instead, the incidence of obesity, type II diabetes and associated diseases have reached epidemic proportions owing in part to replacement of dietary fat with refined carbohydrates. Despite the content of saturated fatty acids in beef, it is also rich in heart healthy cis-monounsaturated fatty acids, and can be an important source of long-chain omega-3（n-3） fatty acids in populations where little or no oily fish is consumed. Beef also contains polyunsaturated fatty acid biohydrogenation products,including vaccenic and rumenic acids, which have been shown to have anticarcinogenic and hypolipidemic properties in cell culture and animal models. Beef can be enriched with these beneficial fatty acids through manipulation of beef cattle diets, which is now more important than ever because of increasing public understanding of the relationships between diet and health. The present review examines recommendations for beef in human diets, the need to recognize the complex nature of beef fat, how cattle diets and management can alter the fatty acid composition of beef, and to what extent content claims are currently possible for beef fatty acids.

Reproductive performance and gestational effort in relation to dietary fatty acids in guinea pigs

Background： Dietary saturated（SFAs） and polyunsaturated（PUFAs） fatty acids can highly affect reproductive functions by providing additional energy, modulating the biochemical properties of tissues, and hormone secretions. In precocial mammals such as domestic guinea pigs the offspring is born highly developed. Gestation might be the most critical reproductive period in this species and dietary fatty acids may profoundly influence the gestational effort. We therefore determined the hormonal status at conception, the reproductive success, and body mass changes during gestation in guinea pigs maintained on diets high in PUFAs or SFAs, or a control diet.Results： The diets significantly affected the females＇ plasma fatty acid status at conception, while cortisol and estrogen levels did not differ among groups. SFA females exhibited a significantly lower body mass and litter size, while the individual birth mass of pups did not differ among groups and a general higher pup mortality rate in larger litters was diminished by PUFAs and SFAs. The gestational effort, determined by a mother＇s body mass gain during gestation, increased with total litter mass, whereas this increase was lowest in SFA and highest in PUFA individuals. The mother＇s body mass after parturition did not differ among groups and was positively affected by the total litter mass in PUFA females.Conclusions： While SFAs reduce the litter size, but also the gestational effort as a consequence, PUFA supplementation may contribute to an adjustment of energy accumulations to the total litter mass, which may both favor a mother＇s body condition at parturition and perhaps increase the offspring survival at birth.

Influences of operating conditions on biocatalytic activity and reusability of Novozym 435 for esterification of free fatty acids with short-chain alcohols:A case study of palm fatty acid distillate

In the present study, the effects of operating conditions on biocatalytic activity and stability of Novozym 435 for repeated-batch biodiesel production from free fatty acid （FFA） were investigated. Thermal deactivation caused by increased operating temperature from 45 to 50 ℃ could seriously affect the reusability of Novozym 435. The deactivation of Novozym 435 during the esterification of oleic acid with ethanol tended to be stronger than that in the system with methanol. Under the optimal conditions, considering both biocatalytic activity and stability of the enzyme, Novozym 435 could be reused for 13 cycles for biodiesel productions from oleic acid and absolute alcohols （methanol and ethanol） with FFA conversions of at least 90%. The presence of 4%-5% water in ethanol significantly affected the reusability of Novozym 435. Changes in the surface morphology of Novozym 435 during the esterification with various conditions were observed. It was revealed that the reduction in catalytic activity was related to the swelling degree of the catalyst surface, Additionally, biodiesel production from low cost renewable feedstocks, such as palm fatty acid distillate （PFAD） and 95% ethanol was examined, The esterification of PFAD with 95% ethanol catalyzed by Novozym 435 in 10-repeated batch operation showed the similar results in FFA conversion as compared to those using oleic acid. Novozym 435 remained active and could maintain 97.6% of its initial conversion after being used for 10 hatches.

Production of biodiesel from palm fatty acid distillate using sulfonated-glucose solid acid catalyst:Characterization and optimization

A palm fatty acid distillate （PFAD） has been used for biodiesel production. An efficient sulfonated-glucose acid catalyst （SGAC） was prepared by sulfonation to catalyze the esterification reaction. The effect of three variables i.e. methanol-to-PFAD molar ratio, catalyst amount and reaction time, on the yield of PFAD esters was studied by the response surface methodology （RSM）. The optimum reaction conditions were： 12.2：1 methanol-to- PFAD molar ratio, 2.9% catalyst concentration and 134 rain of time as predicted by the RSM. The reaction under the optimum conditions resulted in 94.5% of the free fatty acid （FFA） conversion with 92.4% of the FAME yield. The properties of the PFAD esters were determined according to biodiesel standards.

Role of abnormal lipid metabolism in development,progression,diagnosis and therapy of pancreatic cancer

There is growing evidence that metabolic alterations play an important role in cancer development and progression.The metabolism of cancer cells is reprogrammed in order to support their rapid proliferation.Elevated fatty acid synthesis is one of the most important aberrations of cancer cell metabolism.An enhancement of fatty acids synthesis is required both for carcinogenesis and cancer cell survival,as inhibition of key lipogenic enzymes slows down the growth of tumor cells and impairs their survival.Based on the data that serum fatty acid synthase(FASN),also known as oncoantigen 519,is elevated in patients with certain types of cancer,its serum level was proposed as a marker of neoplasia.This review aims to demonstrate the changes in lipid metabolism and other metabolic processes associated with lipid metabolism in pancreatic ductal adenocarcinoma(PDAC),the most common pancreatic neoplasm,characterized by high mortality.We also addressed the influence of some oncogenic factors and tumor suppressors on pancreatic cancer cell metabolism.Additionally the review discusses the potential role of elevated lipid synthesis in diagnosis and treatment of pancreatic cancer.In particular,FASN is a viable candidate for indicator of pathologic state,marker of neoplasia,as well as,pharmacological treatment target in pancreatic cancer.Recent research showed that,in addition to lipogenesis,certain cancer cells can use fatty acids from circulation,derived from diet(chylomicrons),synthesized in liver,or released from adipose tissue for their growth.Thus,the interactions between de novo lipogenesis and uptake of fatty acids from circulation by PDAC cells require further investigation.

Nutrition and metabolism in poultry: role of lipids in early diet

Modern strains of broiler chickens are selected for fast growth and are marketed anywhere from 36 to 49 days after a21-day incubational period. For a viable healthy chick, all the necessary nutrients required for growth and development must be provided by the hen through the fertilized egg. The current feeding strategies for improved growth, health and productivity are targeted towards chicks after hatching. Considering the fact that developing chick embryo spends over 30 % of its total life span inside the hatching egg relying on nutrients deposited by the breeder hen, investigations on nutritional needs during pre-hatch period will improve embryonic health, hatchability and chick viability. In this context, investigations on hatching egg lipid quality is of utmost importance because, during incubation, egg fat is the major source of energy and sole source of essential omega-6（n-6） and omega-3（n-3） fatty acids to the chick embryo.Due to the unique roles of n-3 and n-6 fatty acids in growth, immune health, and development of central nervous system, this review will focus on the role of early exposure to essential fatty acids through maternal diet and hatching egg and its impact on progeny in meat-type broiler chickens.