Greater Fat Deposition Research Articles

Lipoprotein Lipase of Sheep and Rat Adipose Tissues

Lipoprotein lipase preparations were obtained by aqueous extraction of various tissues from sheep and rats. Preparations having high activity towards serum-activated triolein emulsions were obtained from actively growing sheep, provided that the tissue was maintained at 37 degrees C throughout the extraction procedure. Activity of lipoprotein lipase from sheep adipose tissue, like that from the rat, was dependent upon the presence of serum in the reaction mixture, and was optimal at pH 8-9. Inhibition of sheep adipose tissue preparations by protamine sulfate (1 mg/ml) and 0.6 M NaCl was similar to that found for rat adipose tissue preparations. The affinity of the lipoprotein lipase preparation for the activated substrate from sheep and rat adipose tissue was, however, markedly different; sheep preparations being activated at much lower substrate concentrations (Km 0.43 mM) than rat preparations (Km greater than 5 mM). These findings, confirmed with acetone-ether preparations of lipoprotein lipase, indicate that the enzyme from sheep adipose tissue has a greater potential to remove triacylglycerol from the plasma. This could result in a greater deposition of fat in the tissue.

GENETIC CHANGES IN MEAT-TYPE CHICKENS IN THE LAST TWENTY YEARS

Three experimental strains and two modern commercial stocks of meat-type chickens were compared in 1978. One experimental strain, K, an unselected control, represented broilers of 20 yr ago. A second experimental strain, A, selected for high broiler weight and a third, D, selected for high broiler and low adult weights had been derived from strain K and represented experimental strains genetically improved by artificial selection. All stocks were hatched and reared simultaneously using modern industrial practices. At 47 days, 70 birds of each sex and stock were slaughtered and the carcasses chemically analyzed. Also, 25 hens of each of strains A, D and K were slaughtered when 68 wk old and abdominal fat and carcass weight data were analyzed. The selection for higher broiler weight in strain A increased both broiler and adult body weights more and percent carcass fat less than the selection for high broiler and low adult weight in strain D. Relative to strain A, carcass weight of strain D was 10% lower in broilers and 16% lower in adult hens. Respective means for the modern commercial broilers, strain A broilers, and "broilers of 20 years ago" were 1552, 1001 and 676 g dressed carcass weight; 2.4, 1.6 and 1.4% abdominal fat; 17.2, 15.4 and 12.4% carcass fat (wet basis) and 1.90, 1.92 and 2.01 feed conversion. Thus, the modern broilers have a dramatically increased growth rate accompanied by higher fat content. The greater fat deposition may at least partly account for the lack of significant improvement in feed conversion.

Dietary Energy Affecting Growth, Feed Conversion, and Carcass Composition of Holstein Steers

Holstein steers (six per treatment) were fed rations having three contents of energy. High content of dietary energy produced faster gains, more efficient conversion of dry matter to gain, greater deposition of fat, higher carcass quality grade, and more tender steaks than did low dietary energy. Steaks cooked to lower internal temperatures (60C) were more tender and had less loss of juice than steaks cooked to higher temperatures (64 to 72C).

Hereditary obesity and hormone deficiencies in yellow dwarf mice.

Daily injection of 0.05 USPU of ovine growth hormone had no effect on greater fat deposition in yellow dwarf ( Ayadwdw) mice of either sex as compared with nonyellow dwarf mice ( aadwdw). No differences between the accelerated growth rates of both genotypes during the injection period were noted nor were there any marked differences in the increase in tail length between the genotypes. Yellow dwarf mice continued gaining weight more rapidly than nonyellow dwarf mice after the end of the injection period. Analysis of the fat and water content of the carcasses indicates that the greater rate of weight gain of yellow dwarf mice is due almost entirely to increased fat deposition. The results of this experiment suggest that the obesity of yellow mice is not due to deficiencies of growth hormone or thyrotrophin.

EFFECT OF INTRAVENOUS GLUCOSE ON CONCENTRATION OF INSULIN IN MATERNAL AND UMBILICAL-CORD PLASMA.

It has been suggested that the foetus of a diabetic mother is subjected to intermittent hyperglycaemia and that this is followed by pancreatic islet hyperplasia, increased insulin secretion, and greater deposition of fat (Osier, 1960). Measure ments of plasma-insulin-like activity in the newborn in response to a glucose load have shown that the baby of a diabetic mother has a greater rise of insulin-like activity in the plasma than the baby of a normal mother (Baird and Farquhar, 1962). Similar investigations have not been made on the foetus. In order to investigate what effects varying the concentration of glucose in the maternal blood might have upon the blood sugar and plasma-insulin concentration of the foetus, intra venous glucose was administered to mothers in labour. This paper reports maternal and umbilical-cord blood-sugar and plasma-insulin concentrations (a) in normal mothers and (b) in mothers who received glucose infusions or intravenous glucose injections during labour.

Influence of Different Levels of Fat and Protein in Broiler Rations on Live Weight, Dressing Percentage and Specific Gravity of Carcasses

McNally and Spicknall (1950) reported a linear relationship between the specific gravity and fat content of broiler legs. Dansky and Hill (1952) indicated that birds fed a high energy ration deposited more fat on the carcass than did birds on a ration of moderate amount of energy content.Information on the effect of feeding different levels of fat and protein in broiler rations on dressing percentages and fat deposition of the carcass is lacking. Greater fat deposition which results from feeding high energy rations could prove to be of economic importance to poultry processors and manufacturers of poultry meat products because of lower dressing yields and greater cooking loss of the carcass.To determine the influence of different levels of added fat (bleached tallow2) and protein in broiler diets on these factors, 15 different rations formulated to give C:P ratios ranging from 35.7 to 50.1 were fed to broilers from…

The Effects of Diethylstilbestrol, Testosterone, Thiouracil, and Thyroprotein on the Chemical Composition of Broiler Carcasses

ABSTRACT THE synthetic production of estrogenic compounds, thyroprotein preparations and goitrogenic compounds has stimulated interest in recent years in the possibility of economically using these substances in the production of meat and eggs. Some of these compounds have marked effects on rate of growth and fat deposition in chickens. It has been shown that the subcutaneous implantation of stilbestrol pellets in chickens results in greater fat deposition and an improvement in market quality of the carcasses (Lorenz, 1943, 1945; Schnetzler et al., 1945; Glazener and Jull, 1946; Andrews and Bohren, 1947; and Detwiler et al., 1950). Jaap and Thayer (1944) and Thayer et al. (1945) reported that oral administration of diethylstilbestrol to chickens was relatively ineffective in improving market quality of the carcasses and rate of fattening. It has been demonstrated that the feeding of thiouracil to broilers will increase fat deposition (Kempster and Turner, 1945; Andrews and Schnetzler, 1946; Andrews . . .

Fat colour and fur colour in different varieties of rabbit

1. Alarge sample of many varieties of rabbit, fed on diets containing colouring matter, showed a very much higher proportion of yellow fat in true albino (27·2%) than in other (1–9%) rabbits. 2. Yellow fat occurred more frequently in albino males (30·1%) than in albino females (13·2%), but in coloured rabbits yellow fat occurred in about the same proportion for males (1·9%) and females (1·8%). 3. Indoor feeding resulted in greater fat deposition than outdoor grazing but the fat of grazed animals tended to be more deeply pigmented.