Carcass Lipid Content Research Articles

Estimates of Heritability for Plasma Very Low Density Lipoprotein Concentration and Genetic Correlations with Lipid Content, Body Volume, and Density in Coturnix coturnix japonica

Genetic parameters associated with very low density lipoprotein concentration (VLDL) in a randombred population of Coturnix were estimated. Associated traits were: body density, volume, and weight of the live bird, and lipid content of the whole carcass. A total of 739 progeny by 50 sires and 126 dams was the basis of the data. The VLDL was highly heritable (.52) and highly correlated with lipid content (>.50) but correlated to lesser degrees with body density (.24) and body volume (.20). The genetic correlation estimates between VLDL and body weight were small relative to their standard errors.

Dietary protein requirement of fingerlings of the herbivorous carp tawes, Pontius gonionotus (Bleaker)

. The dietary protein requirement of fingerlings of Pontius gonionotus (Bleaker) was investigated by feeding five isoenergetic semi-purified diets containing varying levels of dietary protein within a range of 15%–557% by weight over a 70-day feeding period. On the basis of percentage weight gain, daily weight gain, specific growth rate and daily tissue protein deposition the dietary protein requirement of fingerlings of P. gonionotus was approximately 35% when fish meal, blood meal and casein were used as the dietary protein source. Feed conversion ratio, protein efficiency ratio and apparent net protein utilization all decreased with increasing dietary protein levels while apparent protein digestibility was not significantly affected. There was a significant increase in carcass moisture and a decrease in carcass lipid content with progressive dietary protein substitution whilst carcass protein and ash were relatively unaffected.

Effects of pre- and early postnatal protein malnutrition on carcass composition and lipoprotein lipase activity in male rats

Little is known about the effects of pre- and early postnatal protein malnutrition on energy storage (e.g., carcass lipid) and expenditure (e.g., brown adipose tissue [BAT] thermogenesis) and their reversibility by nutritional rehabilitation. Therefore, the purpose of these experiments was to examine the permanence of prenatal and early postnatal protein malnutrition on energy balance in rats. Five weeks before mating and through gestation adult female rats were fed either a 25 or 8% casein diet (designated 25 or 8). Diet reversals were performed at birth and/or weaning (designated B or W) and the pups were cross-fostered at birth. Thus, the groups were: (1) 25-25B (controls), (2) 8–25W (gestational and lactational protein malnutrition, (3) 82–5B (gestational protein malnutrition), and (4) 25-8B-25W (lactational protein malnutrition). Animals were weighed and sacrificed 200–250 days postpartum for carcass composition. Retroperitoneal white adipose tissue (RWAT) and interscapular BAT (IBAT) wet weights and lipoprotein lipase (LPL) activity were also measured in the 25-25B and 8–25W groups. Nutritional rehabilitation at birth (8–25B) resulted in normal body weights as adults. Lactational protein malnutrition (25-8B-25W) resulted in intermediate body weights to the controls (25-25W), which had the greatest weights, and the 8–25W group, which had the lowest weights. The 8–25W and 25-8B-25W rats also had significantly decreased carcass wet weight and total body water, fat and fat-free dry mass relative to the 25-25B and 8–25B groups, the latter two of which did not differ in their carcass composition. The 8–25B and 25-8B-25W groups exhibited a selective decrease in the percent of the carcass as lipid. Despite more than 6 months of nutritional rehabilitation beginning at weaning (8–25W), IBAT wet weight, total protein, and specific LPL activity (LPL activity per mg protein) were decreased relative to the 25-25B rats. Total IBAT LPL activity did not differ between the groups. Similarly, the 8–25W rats had decreased RWAT wet weight and total RWAT LPL activity relative to the 25-25B group. The critical time period for protein malnutrition to affect the mechanisms underlying the decreases in body mass and carcass lipid content may be during lactation, since the offspring of prenatally protein malnourished rats cross-fostered at birth to mothers fed a nutritionally adequate protein diet (8–25B) did not exhibit the selective decrease in carcass lipid content, but the offspring of gestational and lactational protein malnourished mothers (8–25W), and, more importantly, the offspring of lactationally protein malnourished mothers (25-8B-25W), both had decreased body weights and carcass lipid content despite the extended nutritional rehabilitation.

Dietary carbohydrate and growth, body composition and heat increment in rainbow trout (Salmo gairdneri)

A study was conducted to determine growth, body composition and heat increment (HI) of rainbow trout reared on isonitrogenous high digestible carbohydrate (HC) and high fat (HL) diets at 15°C. Trout reared on the HC diet had a significantly lower final body weight and carcass lipid content and a significantly higher feed:gain ratio and carcass protein content than trout reared on the HL diet after 12 weeks on the test diets. The lower carcass lipid composition indicates that trout do not readily convert dietary carbohydrates into fat. HI of trout reared on the HC diet was significantly higher than that of fish reared on the HL diet. Considering the poor utilization of dietary carbohydrates as an energy source and the apparently low conversion of dietary glucose into fat, the cause of the higher HI associated with the HC diet is not completely understood. However, it is possible the elimination of excess dietary glucose is an energy dependent process resulting in an increased heat production which would partly account for the increased HI. Furthermore, if the HC diet is a low net energy diet, then the metabolism and utilization of dietary and tissue proteins (amino acids) for energy by the trout may also be partly responsible for the increased HI of the trout reared on the HC diet.

National estimates of the body composition of British cattle, sheep and pigs with special reference to trends in fatness

1The relationship between diet and health is now a major factor in the development of production and marketing strategies for the British meat industry, following Government recommendations that people should be encouraged to eat less fat. It has emphasised the need for accurate information on the body composition of national livestock populations and the fat content of the meat and meat products derived from them. This paper collates the information available for cattle, sheep and pigs, and provides base-line (1984) estimates of national lean and fat production. Changes that have taken place over the past ten years are also examined.2The basic framework for making estimates was the distribution of carcasses between fatness ranges in the national carcass classification schemes operated by the Meat and Livestock Commission (MLC). The distribution for cattle was obtained from a random 1 in 3 sample of beef carcasses classified (0.25 of all clean beef carcasses were classified).3A computer spread-sheet was constructed relating the midpoint means of the fatness ranges to carcass tissue proportions and chemical composition. Regressions for predicting carcass lean and fat content were calculated from accumulated data from surveys of commercial carcasses and breed evaluations for cattle (Kempster, 1986), for sheep (Kempster, Jones and Wolf, 1986a) and for pigs (Diestre and Kempster, 1985). Key regressions are given in Table 1. Carcass lean and fat are defined as in the standard MLC tissue separation procedure. Regressions for estimating carcass lipid content: were obtained using data from several studies. The principal study involved carcasses from breed comparison trials (MAFF/MLC, 1982). Details of the other data sets are given by Kempster, Cook and Grantley-Smith (1986b). Key relationships are given in Table 2.4Estimates of the composition of carcasses in different classification fatness ranges are given in Table 3. These are for 'clean' cattle, sheep and pigs, but estimates were also made for cull cows and cull ewes.5National estimates of carcass composition and the weights of lean and fat produced in 1975/77 and 1984 are given in Table 4. The carcass composition of beef was the same in 1974/76 and 1984 but the average carcass weight has increased by 20kg. The implication of this is that changes in breed and production system have created the potential for leaner carcasses but that the beef industry has preferred to exploit this potential by increasing carcass weights. An increase of 20kg is equivalent to about 15gAg separable fat in carcass on the basis of typical regressions within breed and system.The carcasses of clean sheep in 1984 were estimated to be slightly lighter and leaner than those in 1977. Information on marketing patterns suggests that there has been little change in production methods (as far as they affect composition) and that lambs are now being slaughtered early, possibly stimulated by the pattern of Guide Prices in the EEC Sheep Meat Regime.In marked contrast to cattle and sheep, the separable fat content of the average pig carcass has fallen from 274g/kg in 1975 to 228g/kg in 1985, with a small increase in carcass weight. It is estimated that the increase in the use of entire males has contributed 5g/kg to the overall change.6The estimates in the paper are considered to be the best available with current information but because of the limitations of the data may be subject to error. Possible sources of error are discussed by Kempster et al (1986b). The authors would be pleased to know of data relating physical and chemical composition that could be used to refine the estimates.

The effect of diet on food intake and adiposity in rats made obese by gestational undernutrition

Undernutrition limited to the first two weeks (trimesters) of pregnancy in rats produces a delayed-onset enhancement of body weight and food intake in male but not female offspring. Adiposity measures (fat cell size, fat pad weight and carcass lipid content) however, were enhanced only in male offspring of previously deprived mothers maintained on a high-fat diet. Previous work had shown that although these adiposity differences are enhanced by this diet, hyperphagia was eliminated when animals were switched to the high-fat diet as adults. The current study demonstrates that if offspring of deprived animals are exposed to the high-fat diet early in life, hyperphagia ensues. Adipocyte number, and circulating triglyceride levels were unaffected by our nutritional manipulation.

Recovery of white adipose tissue after lipectomy in female ground squirrels

Female golden-mantled ground squirrels were subjected to surgical removal of adipose tissue (lipectomy) at 4 months of age. Compensation for the 9.6% reduction in body mass effected by lipectomy was observed within 2 weeks and body mass did not differ between lipectomized and sham-lipectomized groups from that time to the conclusion of the experiment. At the time of the second peak in body mass, approximately 11 months postoperatively, lipectomized and sham-lipectomized groups did not differ with respect to total carcass lipid content, water content, or fat-free dry mass. Restoration of body mass after lipectomy did not involve measurable increases in food consumption. There was complete restoration of the retroperitoneal fat depot, but little if any recovery in the parametrial fat depot which was reduced in mass by 75% relative to that of the sham-lipectomized squirrels. Precise regulation of the adipose tissue mass is an important component of the annual cycle in energy balance of female squirrels.

Body weight, food intake and energy regulation in exercising and melatonin-treated siberian hamsters

The coupling among energy intake, storage, and expenditure was examined in male Siberian hamsters (Phodopus sungorus sungorus) given access to running wheels for 14 weeks. Half of the hamsters were injected with melatonin in a schedule that mimics the effects of short photoperiods by decreasing body weight, carcass lipid content, and testis weight. The exercise-induced body weight increases which are seen in Syrian hamsters (Mesocricetus auratus) were not found in Siberian hamsters. Instead, the Siberian hamsters maintained their body weights, compensating for the increased energy demands of exercise by increasing their food intakes. Exercise did not affect carcass composition. Melatonin treatment decreased food intake and carcass lipid stores but did not affect voluntary exercise. The previously reported decrease in testis weight was seen in all melatonin-treated hamsters, but the stimulation of brown adipose tissue growth was not. Thus, exercising Siberian hamsters, unlike exercising Syrian hamsters, appear to exhibit a tight coupling among energy intake, storage, and expenditure.

The nutritional evaluation of dried earthworm meal (Eisenia foetida, Savigny, 1826) included at low levels in production diets for rainbow trout, Salmo gairdneri Richardson

Abstract. Dried earthworm meal derived from the species Eisenia foetida was nutritionally evaluated as a replacement for herring meal in production diets from rainbow trout, Salmo gairdneri Richardson. Increasing levels of dried E. foetidameal, from 5 to 30% by weight, were included in the diet and the response of fish fed these diets was compared to fish fed a control diet without earthworm meal inclusion. There was no evidence of any adverse effect on the growth performance or feed utilization efficiency of fish fed diets containing these low levels of dried E. foetida meal. There was. however, a significant increase in the whole carcass lipid content of fish fed diets containing 5. 10 and 20% dried E. foetida meal. Concent rations of iron, zinc, lead, copper and cadmium within the whole fish carcass were not significantly elevated as a result of including these low levels of the dried E. foetida meal in diets for rainbow trout.

Influence de la température ambiante sur l'utilisation métabolique de l'énergie et de l'azote alimentaires chez le rat en croissance

Sixty-seven male rats of the Wistar CF strain were used in two trials to study the effect of ambient temperature on nitrogen and energy balances (experiment 1) and on the variations of certain biochemical parameters of metabolism (experiment 2). In both cases, the rats, housed individually in metal cages and fed ad libitum, were kept under three different temperatures : 21 degrees C (control), 3 degrees C (cold), 31 degrees C (hot). Compared to the controls, the rats at 3 degrees C showed a significant increase (P less than 0.01) in food intake and a significant decrease (P less than 0.01) in daily growth rate and feed efficiency ratio; body fat content was unchanged. Compared to the controls, the rats at 31 degrees C showed a decrease (P less than 0.01) in food intake and growth rate, a better feed efficiency ratio (P less than 0.01) and a significant increase in carcass lipid content. When compared to rats at 21 degrees C, those at 3 degrees C had a much lower nitrogen retention; at 31 degrees C this retention was only slightly lower. The urinary nitrogen excretion, increased by the cold temperature, reflected higher nitrogen catabolism, while its increase at a high temperature was probably due to a decrease in protein synthesis, and a subsequent degradation of excess ingested nitrogen. Energy retention increased (P less than 0.01) as the ambient temperature increased from 3 to 31 degrees C, and wide variations in the amounts of fixed energy in the form of proteins or lipids were observed. The balance results obtained have been discussed in relation to the variations of some biochemical parameters of metabolism such as free fatty acids, free glycerol, lipoprotein-lipase activity and in vitro utilization of labelled glucose.

Short photoperiods counteract the effects of ovariectomy on energy balance of voles.

Adult female meadow voles maintained from birth in a long photoperiod (14 h light, 10 h darkness; LD 14:10) were ovariectomized or sham-ovariectomized and housed subsequently in long or short (LD 10:14) photoperiods for 10 wk. Absolute and relative daily food intake, body mass, carcass lipid and water content, and lipoprotein lipase activity of white adipose tissue were reduced in voles housed in short photoperiods. Ovariectomy resulted in increases in food intake and body weight and altered carcass composition in long-day voles, but these changes were negated in voles kept in short photoperiods. Responsiveness to short photoperiods promotes winter weight loss and subsequent energy intake savings and counteracts the body weight increases normally associated with gonadal quiescence and diminished hormone secretion.

Colestipol and energy restriction as an approach to hasten removal of PBBs from chickens.

Male White Leghorn chickens were fed either 0.1 or 1.0 ppm fireMaster FF-1 (FF-1) for 21 d. During the withdrawal phase, the chickens were fed 0, 0.5, or 2.5% colestipol hydrochloride, and anion exchange resin. Also, calories were restricted to 80% of control intake within certain groups during the first 14 d in each of 2 consecutive 21-d withdrawal periods. In the caloric-restricted groups, colestipol was fed at 0, 0.625, or 3.125% to yield equal daily intake of colestipol to those fed 0, 0.5, or 2.5% concentrations. During the first 21 d of withdrawal, colestipol at 2.5-3.125%, but not 0.5-0.625%, hastened excretion of polybrominated biphenyls (PBBs) by 50%. During d 22-42 of withdrawal, a background level of PBBs contamination was detected, which tended to confound the results. Despite this, higher levels of colestipol lowered overall body burdens of PBBs by 80% in comparison to the overall level of residues in the other groups of chickens, and by 20% in comparison to their own levels 21 d earlier. Dietary colestipol resulted in chickens with lower carcass lipid content. The combination of energy restriction plus colestipol at 2.5-3.125%, which had the greatest impact in reducing body weight gain and carcass lipid, seemed to be the most favorable treatments for hastening excretion of PBB residues.

Effect of surcose overfeeding on brown adipose tissue lipogenesis and lipoprotein lipase activity in rats

During cold-induced nonshivering thermogenesis, interscapular brown adipose tissue (BAT) lipoprotein lipase (LPL) activity and lipogenesis are elevated. Because of the many similarities between cold- and diet-induced thermogenesis, we examined the effect of ad libitum access to a 32% sucrose solution on caloric intake, adiposity, and BAT enzyme activities in male rats. Daily caloric intakes of sucrose-fed animals were elevated by 20%–25%, and 8 wk of sucrose feeding doubled carcass fat content. This sucrose-feeding induced obesity was associated with increases in circulating triglyceride and insulin levels as well as increased retroperitoneal white adipose tissue LPL activity. However, the increased carcass lipid content accounted for less than half of the excess calories ingested by the sucrose-fed rats. Sucrose feeding stimulated in vivo lipogenesis in BAT and elevated BAT fatty acid synthetase and acetyl-CoA carboxylase activities but not LPL activity. These findings suggest that overeating enhances endogenous lipogenesis but not uptake of circulating triglyceride in BAT. Thus, both cold- and diet-induced thermogenesis increase BAT lipogenesis, while only cold-induced thermogenesis is associated with elevated LPL activity in BAT.

Dietary obesity in golden hamsters: Reversibility and effects of sex and photoperiod

Golden hamsters fed a high-fat diet do not overeat, but they become obese because of decreases in energy expenditure. This decrease in actual energy expenditure is accompanied by increases in thermogenic capacity and brown adipose tissue mass, protein content, and DNA content. Three experiments examined this phenomenon in more detail. Experiment 1 demonstrated that this form of dietary obesity is largely reversible simply by returning the animals to a high-carbohydrate chow diet. However, the obesity which develops solely because of decreased energy expenditure is reversed primarily by decreased energy intake. In this respect fat-fed hamsters resemble tube-fed rats. Experiment 2 revealed that the effects of high-fat diet are at least as robust in female hamsters as in males. Experiment 3 examined the interactions between diet and photoperiod. Short days (10 hr light per 24 hr) had almost no effect on male hamsters fed Purina chow. However, nearly all of the effects of the high-fat diet (i.e., increases in body weight gain, feed efficiency, carcass energy content, percent ingested energy stored in the carcass, carcass lipid content, brown adipose tissue protein, and brown adipose tissue DNA) were exaggerated in hamsters housed in short days. High-fat-diet-induced increases in metabolic efficiency and thermogenic capacity may be of value in readying hamsters for winter. Furthermore, as winter approaches, decreasing day length might synergize with changes in diet quality to promote these beneficial changes in energy metabolism. Finally, fat-fed hamsters could be a useful animal model of some kinds of human obesity.

Diurnal variation in somatotrop activity and correlated changes in plasma free fatty adds and tissue lipid levels in rainbow troutSalmo Gairdneri

Abstract Rainbow trout (Salmo gairdneri) were adapted to long (LD = 12:12) or short (LD = 8:16) daily photoperiods and pituitary, plasma and tissues were collected from fish sampled over a 24 h period to examine possible diurnal variation in pituitary somatotrop activity, plasma free fatty acid (FFA) concentration and liver, muscle and carcass lipid content. Trout acclimated to both long and short daily photoperiods showed a similar significant daily cycle of somatotrop activity with peak activity occurring during the second half of the dark phase. Plasma FFA levels in trout on a long photoperiod similarly showed a significant diurnal variation and there was a significant direct correlation between somatotrop activity and plasma FFA concentration, whereas in trout acclimated to a short daily photoperiod plasma FFA levels did not vary diurnally and there was a significant inverse correlation between somatotrop activity and plasma FFA levels. There were no consistent diurnal changes in liver, muscle or carcas lipid content with the possible exception of an increase in muscle lipid content in the second half of the dark period in trout acclimated to the short daily photoperiod.

Sympathetic activity in thyroid-treated Zucker rats.

Treatment of lean and obese 3- to 4-mo-old male Zucker rats with 0.03% thyroid powder (TP) for up to 41 days produced a decreased weight gain and carcass lipid content in obese but not lean rats, without reduction in food intake. Improved thermogenesis in TP-treated obese rats was evidenced by increased basal rectal temperatures and improved cold tolerance, although TP did not alter the lower stress-evoked levels of plasma norepinephrine (NE) or epinephrine of the obese rats. Levels of NE and/or NE turnover were lower in hearts, aortas, pancreata, interscapular brown adipose, and epididymal white adipose pads of obese compared with lean rats. Both NE levels and turnover were increased in the hearts and aortas of TP-treated obese rats, suggesting increased sympathetic activity in these organs. Basal but not stress-evoked hyperglycemia, hyperinsulinemia, and hyperglycerolemia in the obese rats were partly or totally corrected by TP treatment as was defective in vivo utilization of fatty acids. Therefore 0.03% TP administration had a selective effect on the obese Zucker rat compared with the lean and led to decreased weight gain associated with improved thermogenesis. These effects appeared to be related in part to increased sympathetic function in some organs and improved utilization of fatty acids.

The role of vagally-mediated hyperinsulinemia in hypothalamic obesity

Evidence that the obesity syndrome which follows ventromedial hypothalamic (VMH) lesions is at least partially the result of a primary metabolic dysfunction is reviewed, as are proposals that the altered metabolism is due to enhanced vagally-mediated insulin release. This hypothesis was based largely on experiments demonstrating the complete reversal of hypothalamic obesity by subdiaphragmatic vagotomy, but subsequent studies have revealed that hypothalamic obesity is not always prevented by prior vagal transections. Interpretation of these discrepant results has been made difficult because of the frequent use of gastric secretion, behavioral, or other indirect tests for completeness of vagotomy. A review of more recent studies which have employed either direct assessment of vagotomy effects on insulin levels, pharmacological blockade of vagal efferent activity, or selective vagotomies indicates that vagally-mediated hyperinsulinemia can account for no more than 40% of the weight gain observed in animals with VMH lesions fed ad libitum, and may not be involved in the obesity that results from some parasagittal VMH knife cuts. It is concluded that vagally-mediated hyperinsulinemia does make a substantial, although not exclusive, contribution to the increased carcass lipid content observed in VMH animals that are food-restricted or pair-fed with control animals.

Effects of bovine growth hormone on plasma FFA concentrations and liver, muscle and carcass lipid content in rainbow trout, Salmo gairdneri Richardson

Bovine growth hormone (GH) given daily to rainbow trout, Sulmo gairdneri for 4 or 7 days at either 10.00 or 14.00 hours, significantly increased plasma free fatty acid (FFA) levels but had not effect on plasma cholesterol levels. Liver lipid content of the GH‐injected trout after seven injections was significantly lower than comparable controls in groups injected at both 10.00 and 14.00 hours. There were no apparent effects of GH on carcass or muscle lipid content although in fish injected and sampled at 14.00 hours there was a significant correlation between the number of injections and carcass lipid content.Changes in hepatosomatic index (HSI), liver, muscle and carcass lipid content, plasma FFA and cholesterol concentrations and somatotrop activity during food‐deprivation for up to 60 days are described. Despite significant decreases in liver and muscle lipid content and increases in plasma FFA levels in food‐deprived fish, there was no concomitant change in apparent somatotrop activity.The data are interpreted to indicate that although exogenous GH, in the doses used here, appears to stimulate mobilization of lipid reserves, particularly from the liver, there is no evidence that enforced changes in lipid reserves elicits a response of the endogenous somatotrop cells.

Testicular effects on food intake, body weight, and body composition in male hamsters

Castration significantly increased body weight gain in male hamsters. Treatment with testosterone propionate (TP), 5α-dihydrotestosterone propionate (DHTP), or estradiol benzoate (EB) prevented the castration-induced weight gains. All of these body weight changes were seen in the absence of significant changes in food intake, suggesting an important role for metabolic actions of testicular steriods. Castration increased carcass lipid content and decreased protein content. Both of these effects were prevented by TP treatment. DHTP treatment prevented only the decrease in carcass protein, and EB treatment prevented only the increase in carcass lipid. The adiposity-reducing action of testosterone may be mediated by aromatized (estrogenic) metabolites, and 5α-reduced metabolites could have some anabolic effects. There was a highly-significant negative correlation between carcass lipid content and epididymal fat pad lipoprotein lipase activity, raising the possibility that in male hamsters testicular effects on adiposity may not be mediated via changes in lipoprotein lipase activity. Some other possible metabolic effects of testicular hormones are considered.

Lack of effect on body weight and content of nitrogen and fat after insulin administration to fetal rats.

The effect of fetal insulin injection on body weight and carcass lipid and nitrogen content was studied in four groups of rat fetuses. In each litter, one fetus in each horn was randomly chosen for treatment with either insulin injection, saline injection, insulin solvent injection or sham operation. Injections were given subcutaneously to the fetuses on days 18 1/2, 19 1/2, and 20 1/2 of gestation. The experimental model and the statistical evaluation took into consideration the influence of the fetal position in the uterine horn as well as the variability of fetal size between different litters. Using this experimental model we found that insulin injections to the fetal rat had no effect on body weight and body composition.