Joel Bitman

DDT induces a decrease in eggshell calcium.

Japanese quail fed o,p′, and p,p′-DDT produced eggs with thinner shells and lower calcium content than usual.

An Improved Copper Reagent for Quantitative Densitometric Thin-Layer Chromatography of Lipids

Abstract Eleven cupric compounds were screened to determine whether a different cupric anion might give greater and more uniform charring responses with lipid classes on TLC plates than cupric acetate. A procedure was developed which used 10% CuSO4 in 8% H3PO4 as a charring reagent. Improved reproducibility of charring was obtained by temperature-programmed heating of the thin layer plates from 30 to 180°C at 10 degrees per minute in the oven of a commercial gas-liquid chromatograph.

Efficiency of transfer of polyunsaturated fats into milk.

Polyunsaturated milk has been produced by feeding cows safflower oil enclosed in a casein coat protected with formaldehyde (SOC-F) or formaldehyde-treated soybean (SB) preparations. The efficiency of transfer of dietary 18∶2 ranged from 17 to 42% for various lots of SOC-F and was only 2–8% for SB (per cent transfer=18.2 in milk fat per dietary 18∶2×100). The 18∶2 content of the milk fat increased from basal levels of 2–3% of total fatty acids to 35% with certain SOC-F levels and 7% with SB. Major compensatory changes were noted in 14∶0 and 16∶0 fatty acids. Blood cholesterol, triglycerides and nonesterified fatty acids all increased markedly as cows were fed increasing amounts of SOC-F. There was no increase in cholesterol in the milk.

Two-Stage, One-Dimensional Thin Layer Chromatographic Method for Separation of Lipid Classes

Abstract A thin-layer chromatographic (TLC) technique was developed for routine analysis of lipid classes of blood, milk, tissue and egg yolk. This procedure provided rapid and reproducible separations suitable for in situ quantitation by densitometry The spotted TLC plate was subjected to two developments in one dimension to separate, in ascending order from the origin: phospholipids, monoglycerides, free fatty acids, cholesterol, 1,2-diglycerides, 1,3-diglycerides, triglycerides, and cholesterol esters. Development 1: chloroform: methanol: acetic acid (98:2:1) to 17.0 cm. Development 2: hexane: ethyl ether: acetic acid (94:6:0.2) to the top of the plate. After air drying, the plate was dipped into a solution of 3% cupric acetate in 8% phosphoric acid for 3 seconds, and heated at 130°C for 30 minutes to char the separated lipid classes. The chromatograms were scanned at 350 nm. Overloading of TLC plates with sample using the spotter resulted in the appearance of distorted kidney-shaped spots. A mathemati...

Circadian and ultradian rhythms of body temperature and peripheral concentrations of insulin and nitrogen in lactating dairy cows

To investigate possible circadian and ultradian periodicities for peripheral insulin and urea in lactating dairy cows, integrated 15-min blood samples were taken sequentially over 48 hr from six cows. In addition, radiotelemetry measurements of body temperature were averaged over the same 15-min periods. Cows were housed in an environmental chamber at 19 degrees C with lights on 0700 to 2300 hr; fed daily at 0900 hr; and milked at 0800 and 2000 hr. For five of the six cows, body temperature showed a circadian rhythm peaking at 2323 hr with an amplitude of 0.34 degree C. For the sixth cow, body temperature was 180 degrees out-of-phase, peaking at 1230 hr with an amplitude of 0.12 degree C. Circadian rhythms for insulin and urea were consistent for all six cows peaking at 1743 hr with an amplitude of 0.74 ng/ml for insulin and at 1034 hr with an amplitude of 3.83 mM for urea. Body temperature and insulin also displayed episodic increases that often exceeded the amplitudes of circadian rhythms. For body temperature, a broad increase in spectral power was seen for periods between 100 and 175 min; time intervals between peaks averaged around 100 min. For insulin, power spectra for individual cows universally indicated rhythms with periods of approximately 45 and 80 min; time intervals between peaks averaged approximately 65 min. For urea, almost all spectral energy was confined to the 24-hr rhythm, although there was evidence of a low-amplitude, 60-min rhythm. In conclusion, when animals are acclimated to a rigidly controlled environment and frequent blood sampling is accomplished with minimal intervention, it is possible to detect rhythms inherent in the regulation of metabolic variables.

Feeding encapsulated oils to increase the polyunsaturation in milk and meat fat

Methods of preparing encapsulated, or protected vegetable oil supplements for feeding ruminant animals to increase the polyunsaturation in milk and meat fat are outlined. The C 18:2 content of milk from cows fed increasing amounts of protected safflower oil during a 6 week dose-response experiment increased from 3 to 30% of total fat. At high levels of C 18:2 in milk fat, whole milks tended to develop an oxidized flavor, which was slight in fresh raw milk but increased markedly after 24 hr. Addition of an antioxidant to fresh milk suppressed this off-flavor. Creams containing high levels of C 18:2 required longer aging times than normal cream for satisfactory churning. Butter containing 16% or more of C 18:2 was soft and somewhat sticky but was much more readily spreadable at refrigerator temperatures than normal butter. Veal fat from supplement fed calves had four times as much C 18:2 as fat from controls.

Embryotoxic and teratogenic effects in unhatched fertile eggs from hens fed polychlorinated biphenyls (PCBs).

SummaryThe PCBs tested with caged White Leghorn hens were ‘Aroclors 1221, 1232, 1242, 1248, 1254, 1268, 5442 and BP-6’, fed at the 20 ppm level. In addition, 1242, 1248 and 1254 were also fed at the 2 ppm level. Feeding 20 ppm ‘Aroclors 1232, 1242, 1248 and 1254’ reduced hatchability and caused teratogenic effects in the embryos. The most common abnormalities found in the unhatched embryos were edema and unabsorbed yolk. Since ‘Aroclors 1221 and 1268’ did not adversely affect embryonic development, adverse effects of the PCBs were not directly related to the degree of chlorination of the biphenyls, or to the amount of total residue.

Quantitative Densitometry in Situ of Lipids Separated by thin Layer Chromatography

Abstract Operating parameters are described for a densitometric method to determine in situ eight lipid classes separated by thin layer chromatography. The separated lipids, visualized on the TLC plate by a cupric acetate-phosphoric acid charring method, were quantitatively determined by spectrodensitometry using the Shimadzu CS-910 Dual Wavelength TLC Scanner. Plates were scanned in either a linear scanning mode or in a zigzag scanning mode (flying spot). Reproducibility of a) sample application (spotting) and b) the lipid separation procedure was determined by scanning. Transmittance measurements yielded response areas that were 2.8 X higher than reflectance measurements. Operating parameters such as scanning direction, wavelength, single and dual-wavelength measurement, scanning speed, and slit geometry were studied. Optimal conditions were established for quantitative densitometry of lipids on thin layer plates.

Lipolysis of triglycerides of human milk during storage at low temperatures: a note of caution.

Summary: Human milk samples were divided at collection and stored at −70°C or −20°C, or extracted immediately with organic solvent, to compare lipid class composition. Storage at −20°C was not satisfactory for maintaining milk lipid composition, for it resulted in hydrolysis of triglycerides and the appearance of free fatty acids.

Lipases and Lipids in Human Milk: Effect of Freeze-Thawing and Storage

ABSTRACT: Frozen storage is often used by milk banks to preserve expressed human milk for later use. Optimal storage and handling conditions which ensure minimum alteration of lipid composition have not been well defined. Therefore we investigated the effect of rapid freeze−thawing and storage conditions (−20 and −70° C) on the free fatty acid (FFA) levels and on the activities of lipoprotein lipase (LPL) and bile salt−stimulated lipase (BSSL) in human milk. Since during mechanical expression leakage of serum components into milk may occur, we also investigated the effect of the presence of serum on human milk LPL during storage. Lipase activity levels were unaffected by rapid freeze−thawing (×3) followed by storage for 1 month at −20 or −70° C. LPL activity (nmol FFA released/ml milk/min) was 414 ± 128, 451 ± 37, and 351 ± 20 and BSSL activity (μmol FFA/ml milk/min) was 5.7 ± 0.7, 5.5 ± 0.8, and 5.7 ± 0.2 in fresh, freeze−thawed, and stored milk, respectively. FFA levels (% of total lipid) were 3.01 ± 1.05 and 10.3 ± 1.6 in fresh−frozen milk stored at −7 0 and −20° C for 5 months, and 3.78 ± 1.08 and 13.60 ± 1.25 in specimens of freeze−thawed (x3) before storage at −70 or −20° C. Addition of serum had no effect on milk LPL at either temperature. We conclude that LPL and BSSL remain fully active during frozen storage of human milk and that milk fat is hydrolyzed at −20° C but not at −70° C. We suggest that banked human milk be stored routinely at −70° C.