Hormonal induction of lactation: estrogen and progesterone in milk

Estrogen and progesterone in milk during the first 21 days of induced and postpartum lactation in Holstein cows and heifers were estimated by assay procedures. Lactation was induced with estradiol-17 beta and progesterone treatment for 7 days. Estrogen and progesterone in induced lactations differed from concentrations in postpartum lactations. In early lactation estrogen was higher in postpartum milk (521 +/- 103 pg/ml on day 1) than in induced milk (336 +/- 46 pg/ml on day 1), but after day 7 the reverse was true (192 +/- 33 pg/ml and 233 +/- 32 pg/ml on day 7). Progesterone remained higher in induced lactation through the first 21 days than in postpartum lactation with the exception of day 19. Progesterone in postpartum milk increased from 4 +/- 1 ng/ml on day 1 to 11 +/- 2 ng/ml on day 21. Progesterone in induced milk showed greater fluctuation (11 +/- 3 ng/ml on day 1 and 22 +/- 9 ng/ml on day 3) but gradually decreased to 12 +/- 2 ng/ml on day 21 (11 +/- 2 ng/ml on day 21 of postpartum lactation).     

Nanobiotechnology perspectives. Role of nanotechnology in the food industry: a review

Nanotechnology is becoming increasingly important for the food sector. Promising results and applications are already being developed in the areas of nutrient delivery systems through bioactive nanoencapsulation, biosensors to detect and quantify pathogens organic compounds, other chemicals and food composition alteration, and even edible film to preserve fruit or vegetables. This article reviews the application and the benefits of nanotechnology in different areas of food industry that include bioactive nanoencapsulation, edible thin film, packages and nanosensors. It is possible to conclude from the review that the nanotechnology advances increase the safety and quality of food and mainly decrease the time for pathogen detection.     

Role of lees in wine production: A review

The sometimes contradictory role attributed by scientists to lees in wine production is discussed in this review. Studies dealing with the importance of lees in the natural removal of undesirable compounds from wine, the effect of lees–wine contact on the volatile fraction of wines, the key influence of lees on biogenic amine contents in wines, the interactions between lees and phenolic compounds, and the importance of mannoproteins and lipids released by lees have been critically reviewed. Finally, the present exploitation of lees is also outlined.     

Artificial induction of lactation in cattle: initiation of lactation and estrogen and progesterone concentrations in milk

Thirty heifers were given 11 subcutaneous injections of 5 mg estradiol benzoate and 200 mg progesterone every 3 d to develop their mammary glands. Three days later groups of animals were treated with 1) 20 mg dexamethasone twice, 2) 500 micrograms cloprostenol thrice, 3) dexamethasone and cloprostenol, 4) oxytocin 4 IU six times, or 5) no further injections. Two further groups of six heifers each (6 and 7) were treated in a manner similar to groups 1 and 3 except the dose of estrogen to develop their mammary glands was doubled to 10 mg/3 d. Six lactating first calf heifers were controls (8). The proportion of animals lactating, combined milk yield for each group (kg), and mean days lactated were 1) 5/6, 3831, 142; 2) 1/6, 912, 195; 3) 6/6, 4898, 194; 4) 3/6, 1066, 128; 5) 1/6, 293, 154; 6) 6/6, 6109, 130; 7) 6/6, 6265, 130; and 8) 6/6, 19, 190, 251. The lactogenic response to dexamethasone and oxytocin is similar to that in sheep, but the response to cloprostenol indicates a species difference. Intensive blood sampling before and after injection of hormones, intended to trigger lactogenesis, showed that plasma prolactin rose to peaks above 210 ng/ml in cows of groups 2, 3, and 4 and were unchanged from the base below 40 ng/ml in groups 1 and 5. Monitoring of steroids after induction treatment showed estradiol-17 beta ranged between 35 and 400 pg/ml and 20 to 80 pg/ml in mammary secretion and plasma and progesterone concentrations were less than at diestrus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of angiotensin in ovarian follicular development and ovulation in mammals: a review of recent advances

Angiotensin (Ang) II is widely known for its role in the control of systemic blood vessels. Moreover, Ang II acts on the vascular control of ovarian function, corpus luteum formation, and luteolysis. Over the past 10 years, our research group has been studying the new concept of the renin-angiotensin system (RAS) as an autocrine/paracrine factor regulating steroidogenesis and promoting different cellular responses in the ovary, beyond vascular function. We have developed and used different in vivo and in vitro experimental models to study the role of RAS in the ovary and a brief overview of our findings is presented here. It is widely accepted that there are marked species differences in RAS function in follicle development. Examples of species-specific functions of the RAS in the ovary include the involvement of Ang II in the regulation of follicle atresia in rats vs the requirement of this peptide for the dominant follicle development and ovulation in rabbits and cattle. More recently, Ang-(1-7), its receptor, and enzymes for its synthesis (ACE2, NEP, and PEP) were identified in bovine follicles, implying that Ang-(1-7) has an ovarian function. Other novel RAS components (e.g. (pro)renin receptor and renin-binding protein) recently identified in the bovine ovary show that ovarian RAS is poorly understood and more complex than previously thought. In the present review, we have highlighted the progress toward understanding the paracrine and autocrine control of ovarian antral follicle development and ovulation by ovarian tissue RAS, focusing on in vivo studies using cattle as a model.     

Screening for estrogen residues in calf urine: comparison of a validated yeast estrogen bioassay and gas chromatography-tandem mass spectrometry.

Within the European Union, the control for residues of illegal hormones in food-producing animals is based on urine analysis for a few target analytes using gas chromatography/mass spectrometry and/or liquid chromatography-tandem mass spectrometry. Recently, we developed a robust yeast bioassay screening tool for estrogens, which was validated as a qualitative screening method in accordance with EC decision 2002/657/EC. In this study, we present long-term performance data and a comparison of urine data obtained with this bioassay, and data from an established gas chromatography-tandem mass spectrometry (GC/MS/MS) confirmatory analysis method. More than 120 calf urine samples from a controlled reference experiment were analysed using both protocols. According to the GC/MS/MS method, only the natural estrogens 17alpha-estradiol and estrone were present in the non-compliant samples. The bioassay was less sensitive than GC/MS/MS for the relatively weak estrogenic compound 17alpha-estradiol, in accordance with expectations. Assuming that application of the mass spectrometric method is considered beyond reasonable doubt, the bioassay performed very well: only 5.6% of the calf urine samples found compliant in GC/MS/MS were screened false suspect in the bioassay screening method. The bioassay results of non-compliant urine samples under routine conditions were as predicted, taking into account the relative estrogenicity of the natural estrogens 17alpha-estradiol and estrone vs. 17beta-estradiol. Only one sample was screened false negative for 17alpha-estradiol and estrone. Application of this fast and simple estrogen bioassay in routine surveillance and control can significantly reduce GC/MS/MS sample workload and allow higher percentages of animals to be screened for potential hormone abuse.     

Zinc in mammalian sperm: a review

The relationship of zinc to morphologic, physiologic, and metabolic functions in the male reproductive system are summarized, and gaps in current understanding are pointed out. Semen and its constituents generally contain high zinc, although concentrations vary among animals and species; the relationships between zinc and fertility of semen is unclear. During zinc deficiency, retarded development of testicular growth involved marked atrophy of tubular epithelium and reduced deoxyribonucleic acid, ribonucleic acid, and protein, as well as reduced zinc contents of testis, epididymis, and dorsolateral prostate. Functions of zinc in hormone interrelationships are little understood, but zinc deficiency decreases output of pituitary gonadotrophins and androgen production, and zinc turnover involves testosterone as well as pituitary hormones. Metabolic regulation of sperm appears to be mediated through zinc as a regulator of enzyme activity in the semen. Within spermatozoa, zinc is closely associated with sulfhydryl groups and disulfide linkages and is concentrated in the tail. Control of motility of sperm by zinc apparently involves control of energy utilization through adenosine triphosphate systems involved in contraction and through regulation of phospholipid energy reserves. The many roles for zinc in the male reproductive system are extremely complex and scarcely understood. The importance of zinc contents of commonly utilized feedstuffs in relation to reproductive capabilities of the mammalian sperm remain unclear, although zinc deficiency in relation to male reproduction may be much more widespread than is recognized commonly.     

Antioxidants in bakery products: a review

Fats impart taste and texture to the product but it is susceptible to oxidation leading to the development of rancidity and off-flavor. Since ancient times it has been in practice to use antioxidants in foods. Discovery of synthetic antioxidants has revolutionized the use of antioxidants in food. The effect of these antioxidants in bakery products were reviewed and found to be effective in enhancing the shelf life. Animal experimental studies have shown that some of the synthetic antioxidants had toxigenic, mutagenic, and carcinogenic effects. Hence there is an increasing demand for the use of natural antioxidants in foods, especially in bakery products. Some of the natural antioxidants such as alpha-tocopherol, beta-carotene, and ascorbic acid were already used in bakery products. These natural antioxidants are found to be effective in enhancing the shelf life of bakery products but not to the extent of synthetic antioxidants. Baking processing steps may lower the antioxidative activity but techniques such as encapsulation of antioxidants can retain their activity. Antioxidative activity of the plant extracts such as garcinia, curcumin, vanillins, and mint were reviewed but studies on their role in bakery products were limited or very few. Hence there is a wide scope for study under this direction in depth.     

巧克力油脂相容性研究进展

通过比较和分析可可脂、类可可脂、月桂酸型代可可脂、非月桂酸型代可可脂、乳脂、坚果油等巧克力用油的二元、三元等固相图,并结合其脂肪酸组成、甘三酯组成、晶体类型、结晶特性等,总结了巧克力用油的相容性,并探讨了可能引起相容性差异的原因,对巧克力用油相容性的评判给出了指导性建议.     

Wood-cement composites: a review

This paper reviews the research reported mostly in the last 10 years in the most common journals on the wood-cement composites field. The focused topics include: the problem of the compatibility (or not) between cement and woods, what causes it, ways of overcoming the problem; methods for manufacture and the properties exhibited by common wood-composites; special techniques to accelerate the curing of cement and to improve the properties of wood-cement composites; manufacture of nonwood vegetable raw materials-cement composites; durability against weathering and fungi; and construction materials. A discussion on the state-of-the-art is also presented.     

Basmati rice: a review

India contributes about one-third of the world acreage under rice. Rice is available in over 5000 varieties, of which Basmati rice occupies a prime position on account of its extra long superfine slender grains, pleasant, exquisite aroma, fine cooking quality, sweet taste, soft texture, length-wise elongation with least breadth-wise swelling on cooking and tenderness of cooked rice. This article reviews the quality and aroma traits of Basmati rice, particularly the varieties grown in different parts of India and Pakistan, the agronomy, breeding and physiology of the grain, the trade scenario, Agmark grade designation for export and the US patent of new hybrid strains of Basmati.     

Invited review: Environmental impacts of dairy processing and products: a review

The objective of this review is to summarize research efforts and case studies to date of the environmental impacts from dairy processing. The pervasiveness of greenhouse gas emission, water use, consumer waste, and other environmental impacts of dairy are described. An outline of the method of choice, the life cycle assessment, for conducting research and deciding appropriate allocation of the impacts is provided. Specific research examples in dairy processing highlight how the representative final product is associated with environmental impacts to air, water, and land. The primary conclusion from the study was the usefulness of life cycle assessment methodology and the need for further research due to limited studies, variable data, and the magnitude of environmental impact.     

Sorption of veterinary pharmaceuticals in soils: a review

Veterinary pharmaceuticals (VPs) are used in large amounts in modern husbandry. Due to their use pattern, they possess a potential for reaching the soil environment. To assess their mobility in soil, the literature on sorption of chemicals used as VPs is reviewed and put into perspective of their physicochemical properties. The compilation of sorption coefficients to soil solids (Kd,solid) demonstrates that these chemicals display a wide range of mobility (0.2 < Kd,solid < 6,000 L/kg). Partition coefficients for association of tetracycline and quinolone carboxylic acid VPs to dissolved organic matter (Kd,DOM) vary between 100 and 50,000 L/kg. The variation in Kd,solid for a given compound in different soils can be significant. For most of the compounds, the variation is not considerably lower for the organic carbon-normalized sorption coefficient Koc. In addition, prediction of log Koc by log Kow leads to significant underestimation of log Koc and log Kd,DOM values. This suggests that mechanisms other than hydrophobic partitioning play a significant role in sorption of VPs. A number of hydrophobicity-independent mechanisms such as cation exchange, cation bridging at clay surfaces, surface complexation, and hydrogen bonding appear to be involved. These processes are not accounted for by organic carbon normalization, suggesting that this data treatment is conceptually inappropriate and fails to describe the sorption behavior. Moreover, prediction of log Koc based on the hydrophobicity parameter log Kow is not successful.     

Volatile flavor compounds in yogurt: a review

Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor.     

Nutraceutical functions of sesame: a review

The results of recent food chemical and nutraceutical studies on the traditionally well-known health value of sesame are described, including some aspects of the utilization of sesame. The highly antioxidative activity of sesame oil was clarified and found to involve newly discovered lignans. The antiaging effect of sesame was elucidated to be due to the strong vitamin E activity caused by a novel synergistic effect of sesame lignans with tocopherols resulting from the inhibition of metabolic decomposition of tocopherols by sesame lignans. The specific inhibitory action of sesame lignans on Delta5 desaturase in polyunsaturated fatty acid synthesis was found in studies on the microbial production of polyunsaturated fatty acids. This effect of sesame lignans was extended to various effects on fatty acid metabolism involving lowering fatty acid concentration in liver and serum due to acceleration of fatty acid oxidation and suppression of fatty acid synthesis, and the controlling influence on the ratio of n-6/n-3 polyunsaturated fatty acids under excess intake of either n-6 or n-3 fatty acids in the diet. Sesame lignans lowered the cholesterol concentration in serum, especially in combination with tocopherol, due to the inhibition of absorption from the intestine and suppression of synthesis in the liver. Sesame lignans also showed other useful functions such as acceleration of alcohol decomposition in the liver, antihypertensive activity, immunoregulatory activities, anticarcinogenic activity, and others.     

木质素分离方法的研究进展

综述现有使用酸、碱、超临界、两水相、缓和氢解、离子液等手段分离木质素的方法,指出现有分离技术的发展方向与趋势.不同分离手段将得到不同结构与性质的木质素,并决定着其后续的使用与开发.组分分离与利用应遵循生态化过程中能量与物质的多级利用与多级循环原则.应开发出以利用木质素为目标的分离手段,并将木质素的结构研究与其应用研究有机结合起来,依据其不同的用途,选择不同的分离方法.